Poor embryo development in post-ovulatory in vivo-aged mouse oocytes is associated with mitochondrial dysfunction, but mitochondrial transfer from somatic cells is not sufficient for rejuvenation.

PubMed

Igarashi, Hideki; Takahashi, Toshifumi; Abe, Hiroyuki; Nakano, Hiroshi; Nakajima, Osamu; Nagase, Satoru

2016-10-01

Does in vivo aging of mouse oocytes affect mitochondrial function? Mitochondrial function was impaired in post-ovulatory in vivo-aged mouse oocytes and microinjection of somatic cell mitochondria did not rescue poor fertilization and embryonic development rates. The mechanisms underlying the decline in oocyte quality associated with oocyte aging remain unknown, although studies have suggested that the decline is regulated by mitochondrial dysfunction. However, only a limited number of studies have provided direct evidence implicating mitochondrial dysfunction in oocyte quality during the aging of oocytes. We used post-ovulatory, in vivo-aged mouse oocytes as a model for studying low-quality oocytes in oocyte aging. Superovulated oocytes released from the oviduct at 14 h and 20-24 h post-hCG injection were designated as 'fresh' and 'aged' oocytes, respectively. Membrane potentials and oxygen consumption in single oocytes were evaluated as measures of mitochondrial function in fresh and aged oocytes. Mitochondrial transcriptional factor A (TFAM) expression levels were examined by western blotting, and colocalization of mitochondria and TFAM was analyzed by measuring immunofluorescence in fresh and aged oocytes. IVF and blastocyst formation rates were calculated after oocyte microinjection with mitochondria derived from liver cells. The average mitochondrial membrane potential in fresh oocytes was significantly higher than that in aged oocytes (P < 0.05). The average oxygen consumption rate in aged oocytes was significantly lower than that in fresh oocytes (P < 0.05). Although total TFAM expression was unchanged, its colocalization with mitochondria decreased in aged oocytes. IVF and blastocyst formation rates for mitochondrion-injected aged oocytes were not significantly different from those for buffer-injected aged oocytes. Not applicable. A limitation of this study is that we did not examine the effects of microinjecting mitochondria from other somatic cell types into aged oocytes on their fertilization and embryonic development rates. The results from the present study showed that poor embryonic development was associated with impairment of mitochondrial functions in in vivo-aged oocytes. However, the microinjection of mitochondria from liver cells did not improve the low fertilization and embryonic development rates of aged oocytes. It remains to be demonstrated whether oocyte quality can be rescued by the transfer of cytosolic factors or cellular organelles, such as the endoplasmic reticulum or mitochondria, from specific cell types. This study was supported by Grants-in-Aid for General Science Research to Toshifumi Takahashi (No. 25462550) and Hideki Igarashi (No. 26462474). The funding source played no role in study design in the collection, analysis, and interpretation of data; in the writing of the report; and in the decision to submit the article for publication. The authors have no conflict of interest to disclose. © The Author 2016. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Oocyte cryopreservation: where are we now?

PubMed

Argyle, Catrin E; Harper, Joyce C; Davies, Melanie C

2016-06-01

Since the first live birth from oocyte cryopreservation three decades ago, oocyte cryopreservation has become an important component of ART. Cryopreservation techniques have evolved, leading to higher success rates and the introduction of oocyte cryopreservation into IVF clinics worldwide. Concurrently, there has been an increase in patient demand, especially for so-called 'social egg freezing' that allows women to preserve their fertility in anticipation of age-related fertility decline. This review addresses a need to evaluate the current status of oocyte cryopreservation. It explores current techniques and success rates, clinical applications, the rise of elective oocyte cryopreservation, and future implications. A search was performed using Web of Science and PubMed databases for publications between January 1980 and December 2015. Keywords used included 'egg freezing', 'oocyte freezing', 'oocyte cryopreservation', 'oocyte vitrification', and 'fertility preservation'. The success rate of oocyte cryopreservation has risen, and the increasing use of vitrification offers has improved outcomes, with IVF pregnancy rates now similar to those achieved with fresh oocytes. There are conflicting opinions about the comparative success rates of open and closed vitrification. Patients are accessing and receiving oocyte cryopreservation for a wide range of indications, and there has been a marked increase in patient numbers and oocyte cryopreservation cycles. Oocyte cryopreservation for circumventing age-related infertility is becoming more widely accepted. Oocyte cryopreservation is an established component of ART, with vitrification now being the cryopreservation technique of choice. Increasing numbers of women undergo oocyte cryopreservation for both medical and social reasons. It is important to continue auditing outcomes and reporting long-term follow-up of children born from frozen-thawed oocytes. © The Author 2016. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

No difference in mitochondrial distribution is observed in human oocytes after cryopreservation.

PubMed

Stimpfel, Martin; Vrtacnik-Bokal, Eda; Virant-Klun, Irma

2017-08-01

The primary aim of this study was to determine if any difference in mitochondrial distribution can be observed between fresh and cryopreserved (slow-frozen/thawed and vitrified/warmed) oocytes when oocytes are stained with Mitotracker Red CMXRos and observed under a conventional fluorescent microscope. Additionally, the influence of cryopreservation procedure on the viable rates of oocytes at different maturation stages was evaluated. The germinal vesicle (GV) and MII oocytes were cryopreserved with slow-freezing and vitrification. After thawing/warming, oocytes were stained using Mitotracker Red CMXRos and observed under a conventional fluorescent microscope. Mitotracker staining revealed that in GV oocytes the pattern of mitochondrial distribution appeared as aggregated clusters around the whole oocyte. In mature MII oocytes, three different patterns of mitochondrial distribution were observed; a smooth pattern around the polar body with aggregated clusters at the opposite side of the polar body, a smooth pattern throughout the whole cell, and aggregated clusters as can be seen in GV oocytes. There were no significant differences in the observed patterns between fresh, vitrified/warmed and frozen/thawed oocytes. When comparing the viable rates of oocytes after two different cryopreservation procedures, the results showed no significant differences, although the trend of viable MII oocytes tends to be higher after vitrification/warming and for viable GV oocytes it tends to be higher after slow-freezing/thawing. Mitotracker Red CMXRos staining of mitochondria in oocytes did not reveal differences in mitochondrial distribution between fresh and cryopreserved oocytes at different maturity stages. Additionally, no difference was observed in the viable rates of GV and MII oocytes after slow-freezing/thawing and vitrification/warming.

Comparison of glucose metabolism in in vivo- and in vitro-matured tammar wallaby oocytes and its relationship to developmental potential following intracytoplasmic sperm injection.

PubMed

Magarey, Genevieve M; Mate, Karen E

2004-01-01

Although marsupial oocytes undergo nuclear maturation in vitro, there is, at present, no indication of their developmental potential, largely owing to the lack of in vitro fertilisation and related technologies for marsupials. Glucose metabolism has proven a useful indicator of oocyte cytoplasmic maturation and developmental potential in several eutherian species. Therefore, the aims of the present study were to compare: (1) the rates of glycolysis and glucose oxidation in immature, in vitro-matured and in vivo-matured tammar wallaby oocytes; and (2) the metabolic rate of individual oocytes with their ability to form pronuclei after intracytoplasmic sperm injection. The rates of glycolysis measured in immature (2.18 pmol oocyte(-1) h(-1)), in vitro- matured (0.93 pmol oocyte(-1) h(-1)) and in vivo-matured tammar wallaby oocytes (0.54 pmol oocyte(-1) h(-1)) were within a similar range to values obtained in eutherian species. However, unlike the trend observed in eutherian oocytes, the glycolytic rate was significantly higher in immature oocytes compared with either in vivo- or in vitro-matured oocytes (P < 0.001) and significantly higher in in vitro-matured oocytes compared with in vivo-matured oocytes (P < 0.001). No relationship was identified between glucose metabolism and the developmental capacity of oocytes after intracytoplasmic sperm injection when assessed after 17-19 h. Oocytes that became fertilised (two pronuclei) or activated (one or more pronucleus) were not distinguished from others by their metabolic rates. Longer culture after intracytoplasmic sperm injection (e.g. blastocyst stage) may show oocyte glucose metabolism to be predictive of developmental potential; however, culture to the single-cell stage did not reveal any significant differences in normally developing embryos.

The fertilization ability and developmental competence of bovine oocytes grown in vitro

PubMed Central

MAKITA, Miho; UEDA, Mayuko; MIYANO, Takashi

2016-01-01

In vitro growth culture systems for oocytes are being developed in several mammalian species. In these growth culture systems, in vitro grown oocytes usually have lower blastocyst formation than in vivo grown oocytes after in vitro fertilization. Furthermore, there have been a few reports that investigated the fertilization ability of in vitro grown oocytes in large animals. The purpose of this study was to investigate the fertilization process and developmental competence of bovine oocytes grown in vitro. Oocyte-granulosa cell complexes collected from bovine early antral follicles (0.4−0.7 mm in diameter) were cultured for growth with 17β-estradiol and androstenedione for 14 days and matured in vitro. These oocytes were then inseminated for 6 or 12 h, and further cultured for development up to 8 days in vitro. After growth culture, oocytes grew from 95 µm to around 120 µm and acquired maturation competence (79%). Although fertilization rates of in vitro grown oocytes were low after 6 h of insemination, 34% of in vitro grown oocytes fertilized normally after 12 h of insemination, having two polar bodies and two pronuclei with a sperm tail, and 22% of these oocytes developed into blastocysts after 8 days of culture. The fertilization and blastocyst formation rates were similar to those of in vivo grown oocytes. In addition, blastocyst cell numbers were also similar between in vitro and in vivo grown oocytes. In conclusion, in vitro grown bovine oocytes are similar to in vivo grown oocytes in fertilization ability and can develop into blastocysts. PMID:27151093

The fertilization ability and developmental competence of bovine oocytes grown in vitro.

PubMed

Makita, Miho; Ueda, Mayuko; Miyano, Takashi

2016-08-25

In vitro growth culture systems for oocytes are being developed in several mammalian species. In these growth culture systems, in vitro grown oocytes usually have lower blastocyst formation than in vivo grown oocytes after in vitro fertilization. Furthermore, there have been a few reports that investigated the fertilization ability of in vitro grown oocytes in large animals. The purpose of this study was to investigate the fertilization process and developmental competence of bovine oocytes grown in vitro. Oocyte-granulosa cell complexes collected from bovine early antral follicles (0.4-0.7 mm in diameter) were cultured for growth with 17β-estradiol and androstenedione for 14 days and matured in vitro. These oocytes were then inseminated for 6 or 12 h, and further cultured for development up to 8 days in vitro. After growth culture, oocytes grew from 95 µm to around 120 µm and acquired maturation competence (79%). Although fertilization rates of in vitro grown oocytes were low after 6 h of insemination, 34% of in vitro grown oocytes fertilized normally after 12 h of insemination, having two polar bodies and two pronuclei with a sperm tail, and 22% of these oocytes developed into blastocysts after 8 days of culture. The fertilization and blastocyst formation rates were similar to those of in vivo grown oocytes. In addition, blastocyst cell numbers were also similar between in vitro and in vivo grown oocytes. In conclusion, in vitro grown bovine oocytes are similar to in vivo grown oocytes in fertilization ability and can develop into blastocysts.

What does the cryopreserved oocyte look like? A fresh look at the characteristic oocyte features following cryopreservation.

PubMed

Hosseini, Sayyed Morteza; Nasr-Esfahani, Mohammad Hossein

2016-04-01

In October 2012, the American Society for Reproductive Medicine (ASRM) and, in March 2012, the European Society of Human Reproduction and Embryology (ESHRE), lifted the categorization of oocyte cryopreservation as being "experimental" and endorsed its entrance into the mainstream of assisted reproductive techniques. This change in policy, with the considerable advantages that oocytes offer over embryos for cryopreservation, has increased applications of oocyte cryopreservation in assisted reproduction techniques. A deep understanding of oocyte cryobiology, however, is lagging behind the forces propelling the clinical application of oocyte cryopreservation. We have drawn attention to this shortcoming by initiating a debate on whether a vitrified-warmed oocyte has the same characteristics as its fresh sibling. The answer to this question may explain why the oocyte cryopreservation success rate is as yet far from satisfactory and why cryopreserved oocytes should be treated differently from their fresh siblings. A fresh look at the characteristic features of oocytes after cryopreservation is the main scope of this review as a stimulus to further improvement of oocyte cryopreservation. Copyright © 2016. Published by Elsevier Ltd.

Zona pellucida gene mRNA expression in human oocytes is related to oocyte maturity, zona inner layer retardance and fertilization competence.

PubMed

Canosa, S; Adriaenssens, T; Coucke, W; Dalmasso, P; Revelli, A; Benedetto, C; Smitz, J

2017-05-01

Do the mRNA expression levels of zona pellucida (ZP) genes, ZP1, 2, 3 and 4 in oocyte and cumulus cells (CC) reveal relevant information on the oocyte? The ZP mRNA expression in human oocytes is related to oocyte maturity, zona inner layer (IL) retardance and fertilization capacity. ZP structure and birefringence provide useful information on oocyte cytoplasmic maturation, developmental competence for embryonic growth, blastocyst formation and pregnancy. In order to understand the molecular basis of morphological changes in the ZP, in the current study, the polarized light microscopy (PLM) approach was combined with analysis of the expression of the genes encoding ZP1, 2, 3 and 4, both in the oocytes and in the surrounding CC. This is a retrospective study comprising 98 supernumerary human cumulus oocyte complexes (COC) [80 Metaphase II (MII), 10 Metaphase I (MI) and 8 germinal vesicle (GV)] obtained from 39 patients (median age 33.4 years, range 22-42) after controlled ovarian stimulation. Single oocytes and their corresponding CC were analysed. Oocytes were examined using PLM, and quantitative RT-PCR was performed for ZP1, 2, 3 and 4 in these individual oocytes and their CC. Ephrin-B2 (EFNB2) mRNA was measured in CC as a control. Presence of ZP3 protein in CC and oocytes was investigated using immunocytochemistry. Data were analysed using one-parametric and multivariate analysis and were corrected for the potential impact of patient and cycle characteristics. Oocytes contained ZP1/2/3 and 4 mRNA while in CC only ZP3 was quantifiable. Also ZP3 protein was detected in human CC. When comparing mature (MII) and immature oocytes (MI/GV) or their corresponding CC, ZP1/2 and 4 expression was lower in mature oocytes compared to the expression in immature oocytes (all P < 0.05) and ZP3 expression was lower in the CC of mature oocytes compared to the expression in CC of immature oocytes (P < 0.05). This coincided with a significantly smaller IL-ZP area and thickness in mature oocytes than in immature oocytes (all P < 0.05). In mature oocytes, IL-ZP retardance was significantly correlated with the expression of all four ZP mRNAs (all P < 0.05). The oocyte ZP3 expression was the main predictor of the fertilization capacity, next to IL-retardance and IL-thickness. Using stepwise regression analysis, IL-thickness combined with EFNB2 expression in CC and the patient's ovarian response resulted in a noninvasive oocyte fertilization prediction model. Not applicable. This is a retrospective study and the relation of oocyte mRNA levels to fertilization capacity is indirect as oocyte gene expression analysis required lysis of the oocyte. Overall relations between PLM observations, mRNA expression changes and intrinsic oocyte competence were successfully documented. As such PLM and CC gene expression are confirmed as valuable noninvasive techniques to evaluate oocyte competence. This study was funded by University of Torino, Italy, WFWG UZ-Brussel and Agentschap voor Innovatie door Wetenschap en Technologie IWT 110680, Belgium. All authors declare that their participation in the study did not involve actual or potential conflicts of interests. © The Author 2017. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Oocyte transport: Developmental competence of bovine oocytes arrested at germinal vesicle stage by cycloheximide under air.

PubMed

Hashimoto, Shu; Kimura, Kouji; Iwata, Hisataka; Takakura, Ryo

2003-02-01

The effects of the medium (TCM 199 or SOFaa) and temperature (20 or 39 C) during meiotic arrest by cycloheximide (CHX) under air on the developmental competence of bovine oocytes after in vitro maturation (IVM) and fertilization (IVF) were investigated. Oocytes were maintained in meiotic arrest by 10 microg/ml CHX in a 50-microl droplet of 25-mM HEPES-buffered TCM 199 (H199) at 39 C or synthetic oviduct fluid (HSOFaa) at 20 or 39 C in air for 24 h. After release from the arrest, the oocytes was matured and fertilized in vitro and their developmental competence was examined. The developmental rate of oocytes arrested in HSOFaa at 20 C to the blastocyst stage was similar to that of non-arrested oocytes but was significantly higher (P<0.05) than that of oocytes arrested at 39 C in H199 or in HSOFaa. In consideration of oocyte transport conditions, we also investigated the meiotic arrest of oocytes maintained in a 0.25-ml straw by CHX individually with 10 microl HSOFaa or as a group (40-50 oocytes) with 170-200 microl HSOFaa at 20 C in air for 24 h. After release from meiotic arrest, the developmental competence of these oocytes was assessed similarly. The developmental rate of oocytes treated with CHX individually was similar to that of those treated with CHX in 50-microl droplet of HSOFaa at 20 C. However, the developmental rate of oocytes treated with CHX as a group was lower than that of oocytes treated with CHX in a 50-microl droplet. Five blastocysts developed from oocytes maintained in meiotic arrest in a plastic straw were transferred to five recipient heifers. Consequently, three recipients became pregnant and 2 calves were delivered. The results of the present study indicate that bovine oocytes treated with CHX in HSOFaa at 20 C under air retain the same developmental competence as non-arrested oocytes.

From fresh heterologous oocyte donation to autologous oocyte banking.

PubMed

Stoop, D

2012-01-01

Today, oocyte donation has become well established, giving rise to thousands of children born worldwide annually. The introduction of oocyte cryopreservation through vitrification allows the introduction of egg banking, improving the efficiency and comfort of oocyte donation. Moreover, the vitrification technique can now enable autologous donation of oocytes to prevent future infertility. We evaluated fresh heterologous oocyte donation in terms of obstetrical and perinatal outcome as well as of the reproductive outcome of past donors. We then evaluated the efficiency of a closed vitrification device and its clinical applications within ART. Thirdly, we evaluated the opinion of women with regard to preventive egg freezing and the efficiency of a human oocyte in relation to age. Oocyte donation is associated with an increased risk of first trimester bleeding and pregnancy induced hypertension. Donating oocytes does not seem to increase the likelihood for a later need of fertility treatment. The chance of an oocyte to result in live birth (utilization rate) in women <37 years old remains constant with a mean of 4.47%. A significant proportion of young women would consider safeguarding their reproductive potential through egg freezing or are at least open to the idea. The introduction of efficient oocyte cryopreservation has revolutionized oocyte donation through the establishment of eggbank donation. The technique also enables women to perform autologous donation after preventive oocyte storage in order to circumvent their biological clock.

Total number of oocytes and zygotes are predictive of live birth pregnancy in fresh donor oocyte in vitro fertilization cycles.

PubMed

Hariton, Eduardo; Kim, Keewan; Mumford, Sunni L; Palmor, Marissa; Bortoletto, Pietro; Cardozo, Eden R; Karmon, Anatte E; Sabatini, Mary E; Styer, Aaron K

2017-08-01

To evaluate the association of oocyte donor-recipient characteristics, oocyte donor response, and live birth pregnancy rate following fresh donor oocyte IVF-ET. Retrospective cohort study. Academic reproductive medicine practice. Two hundred thirty-seven consecutive fresh donor oocyte IVF-ET cycles from January 1, 2007 to December 31, 2013 at the Massachusetts General Hospital Fertility Center. None. Live birth rate per cycle initiated. The mean (±SD) age of oocyte donors and recipients was 27.0 ± 3.7 and 41.4 ± 4.6 years, respectively. Oocyte donor demographic/reproductive characteristics, ovarian reserve testing, and peak serum E 2 during ovarian stimulation were similar among cycles which did and did not result in live birth, respectively. Overall implantation, clinical pregnancy, and live birth pregnancy rates per cycle initiated were 40.5%, 60.8%, and 54.9%, respectively. The greatest probability of live birth was observed in cycles with >10 oocytes retrieved, mature oocytes, oocytes with normal fertilization (zygote-two pronuclear stage), and cleaved embryos. The number of oocytes (total and mature), zygotes, and cleaved embryos are associated with live birth following donor oocyte IVF cycles. These findings suggest that specific peri-fertilization factors may be predictive of pregnancy outcomes following donor oocyte IVF cycles. Copyright © 2017 American Society for Reproductive Medicine. All rights reserved.

Ethical Dilemmas for Oocyte Donations: Slippery Slope for Conflicts of Interest.

PubMed

Tulay, Pinar

2016-01-01

Oocyte donations have increased with improvements in oocyte cryopreservation procedures in recent years. Women with medical conditions that require chemotherapy or radiotherapy have begun to opt for oocyte cryo¬preservation prior to their treatment or to enroll in an oocyte donation program. Alternatively, some women apply for "third-party" oocyte donation programs for nonmedical reasons such as delayed childbearing. Although society seems to accept oocyte donations for medical reasons, it appears that there are still some moral issues surrounding nonmedical oocyte donations. In this review, the ethical aspects of oocyte donations and donors' perspectives are discussed. With developing technologies, the genetic screening of donors has expanded to include diseases. This review explores the ethical issues involved in genetic screening of gamete donors.

High-throughput optofluidic system for the laser microsurgery of oocytes

NASA Astrophysics Data System (ADS)

Chandsawangbhuwana, Charlie; Shi, Linda Z.; Zhu, Qingyuan; Alliegro, Mark C.; Berns, Michael W.

2012-01-01

This study combines microfluidics with optical microablation in a microscopy system that allows for high-throughput manipulation of oocytes, automated media exchange, and long-term oocyte observation. The microfluidic component of the system transports oocytes from an inlet port into multiple flow channels. Within each channel, oocytes are confined against a microfluidic barrier using a steady fluid flow provided by an external computer-controlled syringe pump. This allows for easy media replacement without disturbing the oocyte location. The microfluidic and optical-laser microbeam ablation capabilities of the system were validated using surf clam (Spisula solidissima) oocytes that were immobilized in order to permit ablation of the 5 μm diameter nucleolinus within the oocyte nucleolus. Oocytes were the followed and assayed for polar body ejection.

Validation of a heterologous fertilization assay and comparison of fertilization rates of equine oocytes using in vitro fertilization, perivitelline, and intracytoplasmic sperm injections.

PubMed

Sessions-Bresnahan, D R; Graham, J K; Carnevale, E M

2014-07-15

IVF in horses is rarely successful. One reason for this could be the failure of sperm to fully capacitate or exhibit hyperactive motility. We hypothesized that the zona pellucida (ZP) of equine oocytes prevents fertilization in vitro, and bypassing the ZP would increase fertilization rates. Limited availability of equine oocytes for research has necessitated the use of heterologous oocyte binding assays using bovine oocytes. We sought to validate an assay using bovine oocytes and equine sperm and then to demonstrate that bypassing the ZP using perivitelline sperm injections (PVIs) with equine sperm capacitated with dilauroyl phosphatidylcholine would result in higher fertilization rates than standard IVF in bovine and equine oocytes. In experiment 1, bovine oocytes were used for (1) IVF with bovine sperm, (2) IVF with equine sperm, and (3) intracytoplasmic sperm injections (ICSIs) with equine sperm. Presumptive zygotes were either stained with 4',6-diamidino-2-phenylindole from 18 to 26 hours at 2-hour intervals or evaluated for cleavage at 56 hours after addition of sperm. Equine sperm fertilized bovine oocytes; however, pronuclei formation was delayed compared with bovine sperm after IVF. The delayed pronuclear formation was not seen after ICSI. In experiment 2, bovine oocytes were assigned to the following five groups: (1) cumulus oocyte complexes (COCs) coincubated with bovine sperm; (2) COC exposed to sucrose then coincubated with bovine sperm; (3) COC coincubated with equine sperm; (4) COC exposed to sucrose, and coincubated with equine sperm; and (5) oocytes exposed to sucrose, and 10 to 15 equine sperm injected into the perivitelline (PV) space. Equine sperm tended (P = 0.08) to fertilize more bovine oocytes when injected into the PV space than after IVF. In experiment 3, oocytes were assigned to the following four groups: (1) IVF, equine, and bovine COC coincubated with equine sperm; (2) PVI of equine and bovine oocytes; (3) PVI with equine oocytes pretreated with sucrose; and (4) ICSI of equine oocytes. Oocytes were examined at 24 hours for cleavage. No equine oocytes cleaved after IVF or PVI. However, ICSI conducted with equine sperm treated with dilauroyl phosphatidylcholine resulted in 85% of the oocytes cleaving. Sperm injected into the PV space of equine oocytes did not appear to enter the ooplasm. This study validated the use of bovine oocytes for equine sperm studies and indicates that failure of equine IVF is more than an inability of equine sperm to penetrate the ZP. Copyright © 2014 Elsevier Inc. All rights reserved.

Efficiency of metaphase II oocytes following minimal/mild ovarian stimulation in vitro fertilization.

PubMed

Zhang, John J; Yang, Mingxue; Merhi, Zaher

2016-01-01

An inverse relationship between oocyte efficiency and ovarian response was reported in conventional IVF. The purpose of this study was to report metaphase II (MII) oocyte efficiency according to oocyte yield in minimal/mild stimulation IVF (mIVF) and to assess whether oocyte yield affects live birth rate (LBR). Infertile women ( n  = 264) aged < 39 years old with normal ovarian reserve who had mIVF were recruited. All participants received the same protocol for ovarian stimulation. All the embryos were cultured to the blastocyst stage and vitrified using a freeze-all approach. This was followed by a single blastocyst transferred to each participant in subsequent cycles over a 6-month period. Ovarian response was categorized according to the number of MII oocyte yield (low: 1-2, intermediate: 3-6 and high ≥ 7 MII oocytes). MII oocyte utilization rate was calculated as the number of live births divided by the number of MII oocytes produced after only one oocyte retrieval and subsequent transfers of vitrified/warmed blastocysts. The main outcome measure was cumulative LBR over a 6-month period. Among all the participants, 1173 total retrieved oocytes (4.4 ± 0.2 per patient) resulted in 1019 (3.9 ± 0.2 per patient) total MII oocytes, a clinical pregnancy rate of 48.1 % and a LBR of 41.2 %. Oocyte utilization rate was inversely related to ovarian response where it was 30.3 % in the "low" vs. 9.3 % in the "intermediate" vs. 4.3 % in the "high" oocyte yield groups ( p  < 0.05). Implantation rate significantly dropped as the number of MII oocytes increased and was highest in the "low" oocyte yield group ( p  < 0.0001). Cumulative LBR was similar in "low," "intermediate," and "high" oocyte yield groups ( p  > 0.05). The number of MII oocytes had poor sensitivity and specificity for predicting a live birth. These data extend the hypothesis of oocyte efficiency reported in conventional IVF protocols to mIVF protocols. Registration clinicaltrials.gov: NCT00799929.

Effect of milrinone on the developmental competence of growing lamb oocytes identified with brilliant cresyl blue.

PubMed

Wang, Liqin; Jiang, Xiangjiu; Wu, Yangsheng; Lin, Jiapeng; Zhang, Li; Yang, Nan; Huang, Juncheng

2016-11-01

Juvenile in vitro embryo transfer is a novel technique that can be used to increase the rate of genetic gain in a population and presents an alternative to embryo technologies on the basis of adult animals. However, oocytes from prepubertal animals have a lower viability than those obtained from adult ewe oocyte donors. In this research, we aimed to determine the optimum concentration and time of treatment of oocytes from prepubertal lambs with brilliant cresyl blue (BCB) stain and milrinone during IVM. This would improve the developmental rate of lamb oocytes and embryos after IVF. First, lamb cumulus-oocyte complexes were cultured under different concentrations (13 or 26 μM) of BCB staining. Treated lamb oocytes were then divided into BCB- (colorless cytoplasm) and BCB+ (colored cytoplasm) groups on the basis of their glucose-6-phosphate dehydrogenase activity. The blastocyst efficiency rate of BCB+ oocytes treated with 13 μM BCB (37.03%) was significantly higher than that of BCB+ oocytes treated with 26 μM BCB (23.25%) and that of nontreated BCB control oocytes (15.37%), as well as that of BCB- oocytes (6.28%). Both control oocytes and BCB+ oocytes exhibited significantly higher cleavage rates (60.15% and 73.44%, respectively) than that of BCB- oocytes (36.19%). Moreover, the diameter and glutathione content of BCB+ oocytes were found to be significantly greater than those of BCB- oocytes (163.37 vs. 159.25 μm and 6.39 vs. 0.26 pM, respectively). After culturing BCB- oocytes in different concentrations of milrinone (0, 50, 75, and 100 μM) for 3, 6, or 9 hours, results reported that supplementation of IVM medium with 75 μM milrinone for 6 hours yielded a significantly higher proportion of blastocysts than the other treatments. These results show that the staining of lamb cumulus-oocyte complexes with 13 μM BCB before IVM may be used to select developmentally competent lamb oocytes. Furthermore, they suggest that milrinone can be used to promote lamb developmental competence of lamb embryos produced during IVF. Copyright © 2016 Elsevier Inc. All rights reserved.

[Wide support for oocyte donation and banking in the Netherlands].

PubMed

Bos, Annelies M E; Klapwijk, Petra; Fauser, Bart C J M

2012-01-01

To assess the general consensus on the cryopreservation of oocytes and the introduction of oocyte banking facilities in the Netherlands. Poll investigation A poll with the use of an online questionnaire was conducted among nearly 19,000 participants of the Dutch EenVandaag opinion panel in May 2011. The poll results were adjusted to the Dutch population based on data from the Dutch Central Office for Statistics for age, gender, education, marital status, geographical area and political preference (measured according to the lower house elections of 2010). The primary endpoints were the percentages of supporters of oocyte freezing for own future use and of the concept of introducing oocyte banking facilities in The Netherlands. The secondary endpoints were the demographic differences between supporters and opponents. Approximately half of 18.911 participants supported oocyte freezing (47%). Fifty-percent of all participants supported oocyte banking in the Netherlands. Supporters of oocyte freezing were mainly women ≤ 45 years of age, who are highly educated and have no children. Four percent of the participating women aged ≤ 45 years would seriously consider obtaining donor oocytes from an available oocyte banking facility. Twelve percent of the participating women ≤ 45 years of age said they would definitely donate their oocytes or would seriously consider donating. Thirty-seven percent of all participants were against the introduction of oocyte banking facilities. The most important arguments against oocyte freezing were that women should reproduce during normal reproductive years and that it was not medically necessary. Poll results showed much support for oocyte freezing and for the introduction of oocyte banking facilities in the Netherlands. In addition, the poll shows that oocyte banking facilities would fulfil a need in the population.

Vitrification of oocytes from endangered Mexican gray wolves (Canis lupus baileyi).

PubMed

Boutelle, S; Lenahan, K; Krisher, R; Bauman, K L; Asa, C S; Silber, S

2011-03-01

Careful genetic management, including cryopreservation of genetic material, is central to conservation of the endangered Mexican gray wolf. We tested a technique, previously used to vitrify human and domestic animal oocytes, on oocytes from domestic dogs as a model and from the endangered Mexican wolf. This method provided a way to conserve oocytes from genetically valuable older female Mexican wolves as an alternative to embryos for preserving female genes. Oocytes were aspirated from ovaries of 36 female dogs in December and March (0 to 65 oocytes per female) and from six female wolves (4 to 73 per female) during their physiologic breeding season, or following stimulation with the GnRH agonist deslorelin. Oocytes from dogs were pooled; half were immediately tested for viability and the remainder vitrified, then warmed and tested for viability. All oocytes were vitrified by being moved through media of increasing cryoprotectant concentration, placed on Cryotops, and plunged into liquid nitrogen. There was no difference in viability (propidium iodide staining) between fresh and vitrified, warmed dog oocytes (65.7 and 61.0%, respectively, P = 0.27). Oocyte viability after warming was similarly assessed in a subset of wolves (4 to 15 oocytes from each of three females; total 29 oocytes). Of these, 57.1% of the post-thaw intact oocytes were viable, which was 41.4% of all oocytes warmed. These were the first oocytes from a canid or an endangered species demonstrated to have maintained viability after vitrification and warming. Furthermore, our results demonstrated that vitrification of oocytes with the Cryotop technique was an option for preserving female gametes from Mexican wolves for future use in captive breeding programs, although in vitro embryo production techniques must first be developed in canids for this technique to be used. Copyright © 2011 Elsevier Inc. All rights reserved.

Serum human chorionic gonadotropin levels on the day before oocyte retrieval do not correlate with oocyte maturity.

PubMed

Levy, Gary; Hill, Micah J; Ramirez, Christina; Plowden, Torrie; Pilgrim, Justin; Howard, Robin S; Segars, James H; Csokmay, John

2013-05-01

To evaluate the correlation of preretrieval quantitative serum hCG level with oocyte maturity. Retrospective cohort study. Military assisted reproductive technology (ART) program. Fresh autologous ART cycles. Serum hCG level the day before oocyte retrieval. Linear regression was used to correlate serum hCG levels and oocyte maturity rates. Normal oocyte maturity was defined as ≥75% and the Wilcoxon rank sum test was used to compare serum hCG levels in patients with normal and low oocyte maturity. Threshold analysis was performed to determine hCG levels that could predict oocyte maturity. A total of 468 ART cycles were analyzed. Serum hCG level was not correlated with hCG dose; however, it was negatively correlated with body mass index (BMI). Serum hCG levels did not differ between patients with oocyte maturity of <75% and ≥75%. Serum hCG levels did not correlate with oocyte maturity rates. Receiver operator characteristic and less than efficiency curves failed to demonstrate thresholds at which hCG could predict oocyte maturity. Serum hCG levels were not correlated with oocyte maturity. Although a positive hCG was reassuring that mature oocytes would be retrieved for most patients, the specific value was not helpful. Copyright © 2013. Published by Elsevier Inc.

Abnormal chromosome behavior in human oocytes which remained unfertilized during human in vitro fertilization.

PubMed

Spielmann, H; Krüger, C; Stauber, M; Vogel, R

1985-09-01

Chromosomal abnormalities and abnormal embryonic development have previously been observed after human in vitro fertilization (IVF). Chromosomal abnormalities may arise not only after fertilization but even earlier during meiotic maturation of human oocytes in culture. Since chromosomal analysis is simple in oocytes during meiotic maturation, the chromosomal status was analyzed in oocytes which remained unfertilized in a human in vitro fertilization program. In 50 fertilization attempts the chromosomes of 62 unfertilized oocytes could be analyzed; 45 of them were in the process of meiotic maturation. In three oocytes two small polar bodies were observed 16-18 hr after insemination in the absence of fertilization. In one oocyte abnormal chromosome behavior was found during the first meiotic division, and in four oocytes during metaphase of the second meiotic division. These data suggest that chromosomal analysis of unfertilized oocytes in human IVF may improve the understanding human oocyte maturation and fertilization.

[CHALLENGING THE OPTIMAL NUMBER OF RETRIEVED OOCYTES AND ITS IMPACT ON PREGNANCY AND LIVE BIRTH RATES IN IVF/ICSI CYCLES].

PubMed

Blais, Idit; Lahav-Baratz, Shirly; Koifman, Mara; Wiener-Megnazi, Zofnat; Auslender, Ron; Dirnfeld, Martha

2015-06-01

Large numbers of retrieved oocytes are associated with higher chances of having cryopreservation of embryos. However, the process entailed exposes women to increased risk for ovarian hyperstimulation syndrome. Furthermore, mild ovary stimulation protocols are more patient-friendly and with less adverse effects. Only limited reports exist on the significance of the number of retrieved oocytes achieved in a single stimulation cycle. To investigate the optimal number of retrieved oocytes to achieve pregnancy and live birth. This retrospective analysis included 1590 IVF cycles. Oocytes maturation, fertilization, cleavage, as well as pregnancy and live birth rates were analyzed according to the number of retrieved oocytes. Oocyte maturation, fertilization and cleavage rates were lower in cycles with more than 10 retrieved oocytes compared with other groups. Live birth rates were highest when the number of retrieved oocytes was 11-15. Retrieval of more than 15 oocytes was not associated with a significant increase in chances of conception and birth. The better oocyte quality with 10 or less oocytes retrieved could be the result of a possible interference with the natural selection, or the minimized exposure of growing follicles to the potentially negative effects of ovarian stimulation. Although the average number of available embryos was higher when more than 10 oocytes were retrieved, achievement of more than 15 oocytes did not improve IVF outcome in terms of pregnancy and delivery rates. Analysis of 1590 IVF cycles including the frozen-thawed transfers shows that the best outcomes were achieved with an optimal number of 11-15 oocytes.

Quality of common marmoset (Callithrix jacchus) oocytes collected after ovarian stimulation.

PubMed

Kanda, Akifumi; Nobukiyo, Asako; Yoshioka, Miyuki; Hatakeyama, Teruhiko; Sotomaru, Yusuke

2018-01-15

The common marmoset (Callithrix jacchus) is an experimental animal that is considered suitable for the creation of next-generation human disease models. It has recently been used in the reproductive technology field. Oocytes can be effectively collected from female marmosets via ovarian stimulation with injections of follicle-stimulating hormone (FSH) and human chorionic gonadotropin (hCG). The oocytes, collected about 28 h after the hCG injection, include both premature oocytes and postmature (in vivo matured; IVO) oocytes, and the premature oocytes can be matured by in vitro culture (in vitro matured; IVM). Although IVM and IVO oocytes are equivalent in appearance at the MII stage, it remains unclear whether there are differences in their properties. Therefore, we investigated their in vitro fertilization and developmental capacities and cytoskeletal statuses. Our findings revealed that the IVM and IVO oocytes had similar fertilization rates but that no IVO oocytes could develop to the blastocyst stage. Additionally, IVO oocytes showed abnormal cytoskeletal formation. It is concluded that IVM oocytes maintain normal function, whereas IVO oocytes would be affected by aging and other factors when they remain for a long time in the ovary. Copyright © 2017 Elsevier Inc. All rights reserved.

Mammalian oocyte growth and development in vitro.

PubMed

Eppig, J J; O'Brien, M; Wigglesworth, K

1996-06-01

This paper is a review of the current status of technology for mammalian oocyte growth and development in vitro. It compares and contrasts the characteristics of the various culture systems that have been devised for the culture of either isolated preantral follicles or the oocyte-granulosa cell complexes form preantral follicles. The advantages and disadvantages of these various systems are discussed. Endpoints for the evaluation of oocyte development in vitro, including oocyte maturation and embryogenesis, are described. Considerations for the improvement of the culture systems are also presented. These include discussions of the possible effects of apoptosis and inappropriate differentiation of oocyte-associated granulosa cells on oocyte development. Finally, the potential applications of the technology for oocyte growth and development in vitro are discussed. For example, studies of oocyte development in vitro could help to identify specific molecules produced during oocyte development that are essential for normal early embryogenesis and perhaps recognize defects leading to infertility or abnormalities in embryonic development. Moreover, the culture systems may provide the methods necessary to enlarge the populations of valuable agricultural, pharmaceutical product-producing, and endangered animals, and to rescue the oocytes of women about to undergo clinical procedures that place oocytes at risk.

Confocal fluorescence assessment of bioenergy/redox status of dromedary camel (Camelus dromedarius) oocytes before and after in vitro maturation.

PubMed

Russo, Roberto; Monaco, Davide; Rubessa, Marcello; El-Bahrawy, Khalid A; El-Sayed, Ashraf; Martino, Nicola A; Beneult, Benedicte; Ciannarella, Francesca; Dell'Aquila, Maria E; Lacalandra, Giovanni M; Filioli Uranio, Manuel

2014-02-18

Reproductive biotechnologies in dromedary camel (Camelus dromedarius) are less developed than in other livestock species. The in vitro maturation (IVM) technology is a fundamental step for in vitro embryo production (IVP), and its optimization could represent a way to increase the success rate of IVP. The aim of the present study was to investigate the bioenergy/oxidative status of dromedary camel oocytes before and after IVM by confocal microscopy 3D imaging. Oocytes were retrieved by slicing ovaries collected at local slaughterhouses. Recovered oocytes were examined before and after IVM culture for nuclear chromatin configuration and bioenergy/oxidative status, expressed as mitochondria (mt) distribution and activity, intracellular Reactive Oxygen Species (ROS) levels and distribution and mt/ROS colocalization. The mean recovery rate was 6 oocytes/ovary. After IVM, 61% of oocytes resumed meiosis and 36% reached the Metaphase II stage (MII). Oocyte bioenergy/redox confocal characterization revealed changes upon meiosis progression. Immature oocytes at the germinal vesicle (GV) stage were characterised by prevailing homogeneous mt distribution in small aggregates while MI and MII oocytes showed significantly higher rates of pericortical mt distribution organized in tubular networks (P<0.05). Increased mt activity in MI (P<0.001) and MII (P<0.01) oocytes compared to GV stage oocytes was also observed. At any meiotic stage, homogeneous distribution of intracellular ROS was observed. Intracellular ROS levels also increased in MI (P<0.01) and MII (P<0.05) oocytes compared to GV stage oocytes. The mt/ROS colocalization signal increased in MI oocytes (P<0.05). This study provides indications that qualitative and quantitative indicators of bioenergy and oxidative status in dromedary camel oocytes are modified in relation with oocyte meiotic stage. These data may increase the knowledge of camel oocyte physiology, in order to enhance the efficiency of IVP procedures.

Pig oocytes with a large perivitelline space matured in vitro show greater developmental competence after parthenogenesis and somatic cell nuclear transfer.

PubMed

Lee, Joohyeong; You, Jinyoung; Lee, Geun-Shik; Hyun, Sang-Hwan; Lee, Eunsong

2013-09-01

The objective of this study was to examine the developmental competence of pig oocytes in relation to the size of the perivitelline space (PVS) of oocytes matured in vitro. Immature oocytes were matured in medium 199 or porcine zygote medium (PZM)-3 containing 108 or 61.6 mM NaCl. In vitro-matured (IVM) oocytes were examined for intracellular glutathione (GSH) level; cyclin-dependent kinase 1 (CDK1), proliferating cell nuclear antigen (PCNA), and extracellular signal-regulated kinase 2 (ERK2) mRNA levels; and developmental competence after parthenogenesis (PA) and somatic cell nuclear transfer (SCNT). IVM oocytes with a larger PVS had higher (P < 0.05) levels of intracellular GSH (1.00 pixels/oocyte vs. 0.57 pixels/oocyte) and blastocyst formation (54.3% vs. 37.3%) after PA than oocytes with a smaller PVS. Culturing oocytes for maturation in PZM-3 with reduced (61.6 mM) NaCl increased (P < 0.05) the size of the PVS (6.4 µm vs. 2.8 µm) compared to control oocytes that were matured in normal PZM-3 containing 108 mM NaCl. Moreover, oocytes with a larger PVS showed higher CDK1, PCNA, and ERK2 mRNA and intracellular GSH levels (1.6 pixels/oocyte vs. 1.2 pixels/oocyte) and increased blastocyst formation after PA (52.1% vs. 40.6%) and SCNT (31.8% vs. 18.2%) than control oocytes. Our results demonstrate that pig oocytes with a large PVS have greater developmental competence after PA and SCNT, which is attributed to improved cytoplasmic maturation based on the enhanced GSH level and transcription factor expression. Further, enlargement of the PVS by culturing in low-NaCl medium improves the developmental competence of pig oocytes. Copyright © 2013 Wiley Periodicals, Inc.

Confocal fluorescence assessment of bioenergy/redox status of dromedary camel (Camelus dromedarius) oocytes before and after in vitro maturation

PubMed Central

2014-01-01

Background Reproductive biotechnologies in dromedary camel (Camelus dromedarius) are less developed than in other livestock species. The in vitro maturation (IVM) technology is a fundamental step for in vitro embryo production (IVP), and its optimization could represent a way to increase the success rate of IVP. The aim of the present study was to investigate the bioenergy/oxidative status of dromedary camel oocytes before and after IVM by confocal microscopy 3D imaging. Methods Oocytes were retrieved by slicing ovaries collected at local slaughterhouses. Recovered oocytes were examined before and after IVM culture for nuclear chromatin configuration and bioenergy/oxidative status, expressed as mitochondria (mt) distribution and activity, intracellular Reactive Oxygen Species (ROS) levels and distribution and mt/ROS colocalization. Results The mean recovery rate was 6 oocytes/ovary. After IVM, 61% of oocytes resumed meiosis and 36% reached the Metaphase II stage (MII). Oocyte bioenergy/redox confocal characterization revealed changes upon meiosis progression. Immature oocytes at the germinal vesicle (GV) stage were characterised by prevailing homogeneous mt distribution in small aggregates while MI and MII oocytes showed significantly higher rates of pericortical mt distribution organized in tubular networks (P < 0.05). Increased mt activity in MI (P < 0.001) and MII (P < 0.01) oocytes compared to GV stage oocytes was also observed. At any meiotic stage, homogeneous distribution of intracellular ROS was observed. Intracellular ROS levels also increased in MI (P < 0.01) and MII (P < 0.05) oocytes compared to GV stage oocytes. The mt/ROS colocalization signal increased in MI oocytes (P < 0.05). Conclusions This study provides indications that qualitative and quantitative indicators of bioenergy and oxidative status in dromedary camel oocytes are modified in relation with oocyte meiotic stage. These data may increase the knowledge of camel oocyte physiology, in order to enhance the efficiency of IVP procedures. PMID:24548378

Dynamic distribution of spindlin in nucleoli, nucleoplasm and spindle from primary oocytes to mature eggs and its critical function for oocyte-to-embryo transition in gibel carp.

PubMed

Sun, Min; Li, Zhi; Gui, Jian-Fang

2010-10-01

Spindlin (Spin) was thought as a maternal-effect factor associated with meiotic spindle. Its role for the oocyte-to-embryo transition was suggested in mouse, but its direct evidence for the function had been not obtained in other vertebrates. In this study, we used the CagSpin-specific antibody to investigate CagSpin expression pattern and distribution during oogenesis of gibel carp (Carassius auratus gibelio). First, the oocyte-specific expression pattern and dynamic distribution was revealed in nucleoli, nucleoplasm, and spindle from primary oocytes to mature eggs by immunofluorescence localization. In primary oocytes and growth stage oocytes, CagSpin accumulates in nucleoli in increasing numbers along with the oocyte growth, and its disassembly occurs in vitellogenic oocytes, which implicates that CagSpin may be a major component of a large number of nucleoli in fish growth oocytes. Then, co-localization of CagSpin and β-tubulin was revealed in meiotic spindle of mature egg, indicating that CagSpin is one spindle-associated factor. Moreover, microinjection of CagSpin-specific antibody into the fertilized eggs blocked the first cleavage, and found that the CagSpin depletion resulted in spindle assembly disturbance. Thereby, our study provided the first direct evidence for the critical oocyte-to-embryo transition function of Spin in vertebrates, and confirmed that Spin is one important maternal-effect factor that participates in oocyte growth, oocyte maturation, and oocyte-to-embryo transition.

From fresh heterologous oocyte donation to autologous oocyte banking

PubMed Central

Stoop, D.

2012-01-01

Introduction: Today, oocyte donation has become well established, giving rise to thousands of children born worldwide annually. The introduction of oocyte cryopreservation through vitrification allows the introduction of egg banking, improving the efficiency and comfort of oocyte donation. Moreover, the vitrification technique can now enable autologous donation of oocytes to prevent future infertility. Methods: We evaluated fresh heterologous oocyte donation in terms of obstetrical and perinatal outcome as well as of the reproductive outcome of past donors. We then evaluated the efficiency of a closed vitrification device and its clinical applications within ART. Thirdly, we evaluated the opinion of women with regard to preventive egg freezing and the efficiency of a human oocyte in relation to age. Results: Oocyte donation is associated with an increased risk of first trimester bleeding and pregnancy induced hypertension. Donating oocytes does not seem to increase the likelihood for a later need of fertility treatment. The chance of an oocyte to result in live birth (utilization rate) in women <37 years old remains constant with a mean of 4.47%. A significant proportion of young women would consider safeguarding their reproductive potential through egg freezing or are at least open to the idea. Discussion and Conclusion: The introduction of efficient oocyte cryopreservation has revolutionized oocyte donation through the establishment of eggbank donation. The technique also enables women to perform autologous donation after preventive oocyte storage in order to circumvent their biological clock. PMID:24753920

Human oocyte cryopreservation and the fate of cortical granules.

PubMed

Ghetler, Yehudith; Skutelsky, Ehud; Ben Nun, Isaac; Ben Dor, Liah; Amihai, Dina; Shalgi, Ruth

2006-07-01

To examine the effect of the commonly used oocyte cryopreservation protocol on the cortical granules (CGs) of human immature germinal vesicle (GV) and mature metaphase II (MII) oocytes. Laboratory study. IVF unit. Unfertilized, intracytoplasmic sperm injected (ICSI) oocytes, and immature oocytes were cryopreserved using a slow freezing-rapid thawing program with 1,2-propanediol (PROH) as a cryoprotectant. Cortical granule exocytosis (CGE) was assessed by either confocal microscopy or transmission electron microscopy (TEM). The survival rates of frozen-thawed oocytes (mature and immature) were significantly lower compared with zygotes. Both mature and immature oocytes exhibited increased fluorescence after cryopreservation, indicating the occurrence of CGE. Mere exposure of oocytes to cryoprotectants induced CGE of 70% the value of control zygotes. The TEM revealed a drastic reduction in the amount of CGs at the cortex of frozen-thawed GV and MII oocytes, as well as appearance of vesicles in the ooplasm. The commonly used PROH freezing protocol for human oocytes resulted in extensive CGE. This finding explains why ICSI is needed to achieve fertilization of frozen-thawed human oocytes.

Serum human chorionic gonadotropin levels on the day before oocyte retrieval do not correlate with oocyte maturity

PubMed Central

Levy, Gary; Hill, Micah J.; Ramirez, Christina; Plowden, Torrie; Pilgrim, Justin; Howard, Robin S.; Segars, James H.; Csokmay, John

2014-01-01

Objective To evaluate the correlation of preretrieval quantitative serum hCG level with oocyte maturity. Design Retrospective cohort study. Setting Military assisted reproductive technology (ART) program. Patient(s) Fresh autologous ART cycles. Intervention(s) Serum hCG level the day before oocyte retrieval. Main Outcome Measure(s) Linear regression was used to correlate serum hCG levels and oocyte maturity rates. Normal oocyte maturity was defined as ≥ 75% and the Wilcoxon rank sum test was used to compare serum hCG levels in patients with normal and low oocyte maturity. Threshold analysis was performed to determine hCG levels that could predict oocyte maturity. Result(s) A total of 468 ART cycles were analyzed. Serum hCG level was not correlated with hCG dose; however, it was negatively correlated with body mass index (BMI). Serum hCG levels did not differ between patients with oocyte maturity of <75% and ≥ 75%. Serum hCG levels did not correlate with oocyte maturity rates. Receiver operator characteristic and less than efficiency curves failed to demonstrate thresholds at which hCG could predict oocyte maturity. Conclusion(s) Serum hCG levels were not correlated with oocyte maturity. Although a positive hCG was reassuring that mature oocytes would be retrieved for most patients, the specific value was not helpful. PMID:23375205

The signaling pathways by which the Fas/FasL system accelerates oocyte aging.

PubMed

Zhu, Jiang; Lin, Fei-Hu; Zhang, Jie; Lin, Juan; Li, Hong; Li, You-Wei; Tan, Xiu-Wen; Tan, Jing-He

2016-02-01

In spite of great efforts, the mechanisms for postovulatory oocyte aging are not fully understood. Although our previous work showed that the FasL/Fas signaling facilitated oocyte aging, the intra-oocyte signaling pathways are unknown. Furthermore, the mechanisms by which oxidative stress facilitates oocyte aging and the causal relationship between Ca2+ rises and caspase-3 activation and between the cell cycle and apoptosis during oocyte aging need detailed investigations. Our aim was to address these issues by studying the intra-oocyte signaling pathways for Fas/FasL to accelerate oocyte aging. The results indicated that sFasL released by cumulus cells activated Fas on the oocyte by increasing reactive oxygen species via activating NADPH oxidase. The activated Fas triggered Ca2+ release from the endoplasmic reticulum by activating phospholipase C-γ pathway and cytochrome c pathway. The cytoplasmic Ca2+ rises activated calcium/calmodulin-dependent protein kinase II (CaMKII) and caspase-3. While activated CaMKII increased oocyte susceptibility to activation by inactivating maturation-promoting factor (MPF) through cyclin B degradation, the activated caspase-3 facilitated further Ca2+releasing that activates more caspase-3 leading to oocyte fragmentation. Furthermore, caspase-3 activation and fragmentation were prevented in oocytes with a high MPF activity, suggesting that an oocyte must be in interphase to undergo apoptosis.

Prospective randomized comparison of human oocyte cryopreservation with slow-rate freezing or vitrification.

PubMed

Smith, Gary D; Serafini, Paulo C; Fioravanti, Joyce; Yadid, Isaac; Coslovsky, Marcio; Hassun, Pericles; Alegretti, José Roberto; Motta, Eduardo L

2010-11-01

To compare cryopreservation of mature human oocytes with slow-rate freezing and vitrification and determine which is most efficient at establishing a pregnancy. Prospective randomized. Academically affiliated, private fertility center. Consenting patients with concerns about embryo cryopreservation and more than nine mature oocytes at retrieval were randomized to slow-rate freezing or vitrification of supernumerary (more than nine) oocytes. Oocytes were frozen or vitrified, and upon request oocytes were thawed or warmed, respectively. Oocyte survival, fertilization, embryo development, and clinical pregnancy. Patient use has resulted in 30 thaws and 48 warmings. Women's age at time of cryopreservation was similar. Oocyte survival was significantly higher following vitrification/warming (81%) compared with freezing/thawing (67%). Fertilization was more successful in oocytes vitrified/warmed compared with frozen/thawed. Fertilized oocytes from vitrification/warming had significantly better cleavage rates (84%) compared with freezing/thawing (71%) and resulted in embryos with significantly better morphology. Although similar numbers of embryos were transferred, embryos resulting from vitrified oocytes had significantly enhanced clinical (38%) pregnancy rates compared with embryos resulting from frozen oocyte (13%). Miscarriage and/or spontaneous abortion rates were similar. Our results suggest that vitrification/warming is currently the most efficient means of oocyte cryopreservation in relation to subsequent success in establishing pregnancy. Copyright © 2010 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

The effect of immature oocytes quantity on the rates of oocytes maturity and morphology, fertilization, and embryo development in ICSI cycles.

PubMed

Halvaei, Iman; Ali Khalili, Mohammad; Razi, Mohammad Hossein; Nottola, Stefania A

2012-08-01

The goal was to evaluate the role of the number of retrieved immature oocytes on mature oocyte counts and morphology, and also the rates of fertilization and embryo development in ICSI cycles. 101 ICSI cycles were included in this prospective evaluation. Patients were divided into 2 groups of A (≤ 2 immature oocytes) and B (> 2 immature oocytes). In sub-analysis, the impacts of the number of GV and MI oocytes were assessed on the rates of fertilization and embryo development. Also, correlations between the numbers of immature and mature oocytes, as well as maternal age between two groups were analyzed. Assessments of oocyte morphology, fertilization, embryo quality and development were done accordingly. There was no correlation between the immature oocytes quantity with the number of mature ones. There were insignificant differences for embryo development between two groups, but fertilization rate was higher in group A (P = 0.03). In sub-analysis, insignificant differences were observed between two groups of ≤ and >2 GV and MI oocytes for rates of fertilization and embryo development. Also, the rates of clinical pregnancy and delivery were insignificant between groups. The rate of morphologically abnormal oocytes had no significant difference between two groups, except for wide perivitelline space (PVS) which was higher in group A (P = 0.03). There was no significant difference for maternal age between two groups. In cases with few retrieved immature oocytes, rates of fertilization and incidence of wide PVS may increase, although immature oocytes may not have any negative impacts on early embryo development, or the rates on number of mature oocytes.

Oocyte holding in the Iberian red deer (Cervus elaphus hispanicus): Effect of initial oocyte quality and epidermal growth factor addition on in vitro maturation.

PubMed

Macías-García, B; González-Fernández, L; Matilla, E; Hernández, N; Mijares, J; Sánchez-Margallo, F M

2018-02-01

Current in vitro embryo production protocols in the Iberian red deer (Cervus elaphus hispanicus) need to be optimized; oocyte harvesting in situ followed by overnight holding could reduce the human effort and shipping costs. In our work, post-mortem ovaries were retrieved, and the oocytes were harvested and allocated to G1 group (good quality) or G2 + G3 group (low quality). The oocytes were separately subjected to immediate in vitro maturation (IVM) or held overnight in a holding medium composed of 40% of TCM 199 with Earle's salts, 40% TCM 199 with Hanks' salts and 20% fetal bovine serum (FBS), at room temperature (16 hr). In vitro maturation was carried out in a basal medium supplemented or not with 50 ng/ml of epidermal growth factor (EGF). Our data showed that addition of EGF to the maturation medium increases the percentage of G1 oocytes reaching metaphase II (3.9% vs. 50%, basal vs. EGF; p < .001) and decreased their degeneration rate (69.9% vs. 22.2%, basal vs. EGF; p < .01) when oocytes were immediately matured. Overnight holding increased the meiotic competence of G1 oocytes (37.5% matured in basal medium) and EGF increased prophase arrest in G2 + G3 oocytes (16.1% vs. 38.8% in germinal vesicle [GV] stage in basal medium vs. EGF added medium; p < .05). Our data demonstrate that oocyte holding can be used in Iberian red deer oocytes. Interestingly, EGF addition increases the oocytes' meiotic competence in immediately matured oocytes but not after oocyte holding depending upon initial oocyte quality. © 2017 Blackwell Verlag GmbH.

Efficiency and kinetics of the in vitro fertilization process in bovine oocytes with different meiotic competence.

PubMed

Horakova, J; Hanzalova, K; Reckova, Z; Hulinska, P; Machatkova, M

2007-08-01

The aim of the study was to investigate the efficiency and kinetics of fertilization in oocytes with different meiotic competence, as defined by the phase of the follicular wave and follicle size. Oocytes were recovered from cows with synchronized estrus cycles, slaughtered in either the growth (day 3) or the dominant (day 7) phase, separately from large, medium and small follicles. The oocytes were matured and fertilized by a standard protocol. Twenty-four hours after fertilization, the oocytes were denuded from cumulus cells, fixed and stained with bisbensimid Hoechst-PBS. Fertilization was more efficient and the first cleavage was accelerated in growth phase-derived oocytes, as shown by significantly higher (p < or = 0.01) proportions of both normally fertilized and cleaved oocytes (68.8 and 25.1%), in comparison with dominant phase-derived oocytes (44.2 and 10.3%). In the growth-phase derived oocytes, proportions of normally fertilized and cleaved oocytes were significantly higher (p < or = 0.01) in oocytes from large (100.0 and 36.4%) and medium (83.3 and 36.5%) follicles than in those from small (54.8 and 14.6%) follicles. The dominant phase-derived oocytes showed higher proportions of normally fertilized and cleaved oocytes in the populations recovered from small (51.5 and 10.0%) and medium (43.1 and 12.0%) follicles than in those from large (25.0 and 0%) follicles; however, the differences were not significant. It can be concluded that: (i) efficiency and kinetics of fertilization differ in relation to oocyte's meiotic competence; (ii) improved development of embryos from oocytes with greater meiotic competence is associated with a more effective fertilization process.

Morphometric assessment of in vitro matured dromedary camel oocytes determines the developmental competence after parthenogenetic activation.

PubMed

Saadeldin, Islam M; Swelum, Ayman Abdel-Aziz; Yaqoob, Syed Hilal; Alowaimer, Abdullah Nasser

2017-06-01

The aim of the current study was to improve the selection method of camel oocytes after in vitro maturation by reducing exclusion criteria that were based only on the presence of the first polar body. A combined nuclear and morphometric assessment of camel oocytes after in vitro maturation was included to perform a judgment. The nuclear status of the oocytes, including the presence of the first polar body, meiosis I stage, and lack of nuclear materials, was investigated. The morphometric criteria that comprised the dimensions of each oocyte were as follows: diameter of the whole oocyte, including the zona pellucida (ZPO), zona pellucida thickness (ZPT), ooplasm diameter (OD), the perivitelline space (PVS) area, and PVS diameter. Among the oocytes with different nuclear status, there were no differences in ZPO and ZPT. However, oocytes with no nuclear material showed a significant reduction in OD (110.19 ± 1.4 μm) and a significant increase in PVS area (2139 ± 324.6 μm 2 ) and PVS diameter (13.9 ± 1.96 μm) when compared with oocytes in the meiosis I stage (117.41 ± 2.85 μm, 1287.4 ± 123.4 μm 2 , and 8.56 ± 0.65 μm, respectively). To simplify the selection, the major difference between meiosis I and degenerated oocytes was the diameter of the PVS, which was greater than the ZPT in degenerated oocytes. Therefore, three groups were morphologically differentiated into oocytes with polar bodies (PB1), meiosis I (MI) oocytes, and degenerated oocytes. MI oocytes were able to extrude the polar body after activation but were not able to develop into blastocysts. In contrast, MI oocytes were able to develop into blastocysts after a biphasic activation protocol in which the oocytes were electrically activated and treated with ionomycin after 2 h. In conclusion, the results obtained by the morphometric assessment allowed us to develop a simple and objective classification system for in vitro matured dromedary camel oocytes, which will lead to accurate oocyte selection for the support of subsequent embryonic development. Copyright © 2017 Elsevier Inc. All rights reserved.

The developmental potential of parthenogenetic and somatic cell nuclear-transferred rat oocytes in vitro.

PubMed

Mizumoto, Shigetoshi; Kato, Yoko; Tsunoda, Yukio

2008-12-01

We examined the optimal conditions for somatic cell nuclear transfer (SCNT) in rat oocytes. First, we compared the effects of two types of inhibitors of spontaneous activation, MG132 and demecolcine, on the developmental potential of parthenogenetic oocytes. The potential of activated oocytes to develop into blastocysts significantly decreased 2 h after oocyte recovery (77% vs. 7%). The developmental potential of oocytes preserved in MG132-supplemented medium for 1 to 4 h was high (62% to 77%), but the potential of those preserved in demecolcine-supplemented medium for 3 and 4 h was low (77% vs. 41% and 37%, respectively). Second, the effect of the duration of parthenogenetic activation on the developmental potential was examined. When oocytes preserved in MG132 for 4 h were treated with 10 mM strontium for 5 or 6 h, the potential of activated oocytes to develop into blastocysts was high (78% and 70%, respectively). Using the optimal conditions for parthenogenetic activation, we examined the potential of rat enucleated oocytes receiving cumulus cells to develop into blastocysts. In contrast to parthenogenotes, the potential of SCNT rat oocytes to develop into blastocysts was low (2%) even if then oocytes were treated with the histone deacetylation inhibitor trichostatin A. The reason for the low developmental potential of rat SCNT oocytes is discussed.

Oxygen consumption is a quality marker for human oocyte competence conditioned by ovarian stimulation regimens.

PubMed

Tejera, Aberto; Herrero, Javier; de Los Santos, M J; Garrido, Nicolás; Ramsing, Niels; Meseguer, Marcos

2011-09-01

To evaluate the effect of different ovarian stimulation protocols on oocyte respiration and to investigate the relationship between oocyte oxygen consumption and reproductive outcome. Prospective observational cohort study. Infertility clinic in a university hospital. A total of 349 oocytes from 56 IVF treatment cycles in our oocyte donation program. None. Average oocyte oxygen consumption rate in fmol/s. We correlated oxygen consumption values with ovarian stimulation features, fertilization, embryo quality on days 2 and 3, and implantation. Differences in the measured oxygen consumption rates were found depending on which type of gonadotropins were used in the stimulation protocol. Higher consumption rates were found for oocytes that underwent normal fertilization compared with rates from nonfertilized or abnormal oocytes (odds ratio = 1.340; 95% confidence intervals = 1.037-1.732). Furthermore, higher oxygen consumption was observed for those oocytes which generated embryos that implanted compared with those that did not implant (6.21 ± 0.849 fmol/s vs. 5.23 ± 0.345 fmol/s. Measurement of oxygen consumption rates for individual oocytes before fertilization provides a noninvasive marker of oocyte quality and hence a quantitative assessment of the reproductive potential for the oocyte. Copyright © 2011 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Liver condition of Holstein cows affects mitochondrial function and fertilization ability of oocytes

PubMed Central

TANAKA, Hiroshi; TAKEO, Shun; ABE, Takahito; KIN, Airi; SHIRASUNA, Koumei; KUWAYAMA, Takehito; IWATA, Hisataka

2016-01-01

The aim of the present study was to examine the fertilization ability and mitochondrial function of oocytes derived from cows with or without liver damage. Oocytes were collected from the ovaries of cows with damaged livers (DL) and those of cows with healthy livers (HL), subjected to in vitro maturation, and fertilized in vitro. A significantly high abnormal fertilization rate was observed for oocytes from DL cows compared to oocytes from HL cows. The time to dissolve the zona pellucida by protease before fertilization was similar between the two liver conditions, whereas after fertilization treatment this time was shorter for DL cows than for HL cows. The percentage of oocytes with equivalent cortical granule distributions underneath the membrane was greater for in vitro matured oocytes from HL cows, whereas an immature distribution pattern was observed for oocytes from DL cows. In addition, a greater percentage of oocytes derived from HL cows released cortical granules following fertilization compared with oocytes from DL cows. Mitochondrial function determined by ATP content and membrane potential were similar at the germinal vesicle stage, but post-in vitro maturation, the oocytes derived from HL cows showed higher values than DL cows. The mitochondrial DNA copy number in oocytes was similar between the two liver conditions for both the germinal vesicle and post-in vitro maturation oocytes. In conclusion, liver damage induces low fertilization, likely because of incomplete cortical granule distribution and release, and the maturation of oocytes from DL cows contain low-functioning mitochondria compared to their HL counterparts. PMID:26832309

Liver condition of Holstein cows affects mitochondrial function and fertilization ability of oocytes.

PubMed

Tanaka, Hiroshi; Takeo, Shun; Abe, Takahito; Kin, Airi; Shirasuna, Koumei; Kuwayama, Takehito; Iwata, Hisataka

2016-06-17

The aim of the present study was to examine the fertilization ability and mitochondrial function of oocytes derived from cows with or without liver damage. Oocytes were collected from the ovaries of cows with damaged livers (DL) and those of cows with healthy livers (HL), subjected to in vitro maturation, and fertilized in vitro. A significantly high abnormal fertilization rate was observed for oocytes from DL cows compared to oocytes from HL cows. The time to dissolve the zona pellucida by protease before fertilization was similar between the two liver conditions, whereas after fertilization treatment this time was shorter for DL cows than for HL cows. The percentage of oocytes with equivalent cortical granule distributions underneath the membrane was greater for in vitro matured oocytes from HL cows, whereas an immature distribution pattern was observed for oocytes from DL cows. In addition, a greater percentage of oocytes derived from HL cows released cortical granules following fertilization compared with oocytes from DL cows. Mitochondrial function determined by ATP content and membrane potential were similar at the germinal vesicle stage, but post-in vitro maturation, the oocytes derived from HL cows showed higher values than DL cows. The mitochondrial DNA copy number in oocytes was similar between the two liver conditions for both the germinal vesicle and post-in vitro maturation oocytes. In conclusion, liver damage induces low fertilization, likely because of incomplete cortical granule distribution and release, and the maturation of oocytes from DL cows contain low-functioning mitochondria compared to their HL counterparts.

GGPP-Mediated Protein Geranylgeranylation in Oocyte Is Essential for the Establishment of Oocyte-Granulosa Cell Communication and Primary-Secondary Follicle Transition in Mouse Ovary.

PubMed

Jiang, Chen; Diao, Fan; Sang, Yong-Juan; Xu, Na; Zhu, Rui-Lou; Wang, Xiu-Xing; Chen, Zhong; Tao, Wei-Wei; Yao, Bing; Sun, Hai-Xiang; Huang, Xing-Xu; Xue, Bin; Li, Chao-Jun

2017-01-01

Folliculogenesis is a progressive and highly regulated process, which is essential to provide ova for later reproductive life, requires the bidirectional communication between the oocyte and granulosa cells. This physical connection-mediated communication conveys not only the signals from the oocyte to granulosa cells that regulate their proliferation but also metabolites from the granulosa cells to the oocyte for biosynthesis. However, the underlying mechanism of establishing this communication is largely unknown. Here, we report that oocyte geranylgeranyl diphosphate (GGPP), a metabolic intermediate involved in protein geranylgeranylation, is required to establish the oocyte-granulosa cell communication. GGPP and geranylgeranyl diphosphate synthase (Ggpps) levels in oocytes increased during early follicular development. The selective depletion of GGPP in mouse oocytes impaired the proliferation of granulosa cells, primary-secondary follicle transition and female fertility. Mechanistically, GGPP depletion inhibited Rho GTPase geranylgeranylation and its GTPase activity, which was responsible for the accumulation of cell junction proteins in the oocyte cytoplasm and the failure to maintain physical connection between oocyte and granulosa cells. GGPP ablation also blocked Rab27a geranylgeranylation, which might account for the impaired secretion of oocyte materials such as Gdf9. Moreover, GGPP administration restored the defects in oocyte-granulosa cell contact, granulosa cell proliferation and primary-secondary follicle transition in Ggpps depletion mice. Our study provides the evidence that GGPP-mediated protein geranylgeranylation contributes to the establishment of oocyte-granulosa cell communication and then regulates the primary-secondary follicle transition, a key phase of folliculogenesis essential for female reproductive function.

Effect of potential oocyte transport protocols on blastocyst rates after intracytoplasmic sperm injection in the horse.

PubMed

Foss, R; Ortis, H; Hinrichs, K

2013-12-01

Intracytoplasmic sperm injection (ICSI) is used to produce foals from otherwise infertile mares and from stallions with limited sperm stores, but requires expensive equipment and is technically demanding. Methods to transport oocytes to ICSI laboratories would allow collection of oocytes by the referring veterinarian and enable greater application of this technique. This study was conducted to evaluate protocols that could be used to transport immature and maturing oocytes for ICSI. In vitro experiment. Oocytes were recovered by transvaginal ultrasound-guided follicular aspiration either from dominant follicles 24 h after deslorelin administration (dominant stimulated follicle [DSF]), or from subordinate (immature) follicles at the same time. To mimic transport, DSF oocytes were incubated overnight under differing conditions before ICSI; immature oocytes were placed in varying conditions overnight before in vitro maturation, followed by ICSI. The rate of blastocyst production was compared among treatments. Blastocysts were produced in all groups. Dominant stimulated follicle oocytes held in sealed tubes in pre-equilibrated control maturation medium maintained at 37°C yielded blastocyst development equal to that obtained for control incubated oocytes (70%). Dominant stimulated follicle oocytes held similarly in a warm passive device yielded poor blastocyst development (10%). Immature oocytes held for one or 2 nights in modified M199 medium, or for one night in commercial embryo holding solution, in air at room temperature, yielded 35-37% blastocyst development per injected oocyte. A commercially available medium can be used for shipping immature oocytes at room temperature with good resulting blastocyst rates. Better blastocyst rates per oocyte are obtained from DSF oocytes; however, these require maintenance at 37°C and as they are already maturing at the time of collection, are more sensitive to delays. This new, practical information supporting transport of both immature and DSF oocytes for ICSI may allow wider use of this procedure. © 2013 EVJ Ltd.

IMPORTANCE OF GLUTATHIONE IN THE ACQUISITION AND MAINTENANCE OF SPERM NUCLEAR DECONDENSING ACTIVITY IN MATURING HAMSTER OOCYTES

EPA Science Inventory

Sperm nuclear decondensing activity in mammalian oocytes is dependent upon the maturational state of the oocyte. It is maximal in mature, metaphase II oocytes and minimal or absent in immature germinal vesicle (GV) and fertilized pronuclear oocytes. Previous studies suggested tha...

Full-grown oocytes from Xenopus laevis resume growth when placed in culture

PubMed Central

Wallace, Robin A.; Misulovin, Ziva; Etkin, Laurence D.

1981-01-01

When most full-grown, follicle cell-invested oocytes from Xenopus laevis are placed in an appropriate culture medium, they resume growth and remain physiologically healthy for at least 2-3 weeks. Rates of growth by full-grown oocytes in vitro generally approximate and can even exceed the most rapid growth rate achieved by vitellogenic oocytes in vivo. Resumption of oocyte growth can be correlated with the loss of investing follicle cells, which under normal conditions appear to interfere with vitellogenin and nutrient access to the oocyte. The final size reached by the oocyte within the ovary is thus not an intrinsic property of the oocyte but is extrinsically imposed by the somatic environment. Images PMID:16593019

Morphological records of oocyte maturation in the parthenogenetic tick Amblyomma rotundatum Koch, 1844 (Acari: Ixodidae).

PubMed

Sanches, Gustavo S; Araujo, Andrea M; Martins, Thiago F; Bechara, Gervásio H; Labruna, Marcelo B; Camargo-Mathias, Maria I

2012-02-01

Oocyte maturation in the thelytokous parthenogenetic tick Amblyomma rotundatum was examined for the first time using light and scanning electron microscopy. The panoistic ovary lacks nurse and follicular cells and is a single continuous tubular structure forming a lumen delimited by the ovarian wall. Oocytes of tick species are usually classified according to cytoplasm appearance, the presence of germinal vesicle, the presence of yolk granules, and the chorion. However, for this species, we also use oocyte size as an auxiliary tool since most oocytes were in stages I-III and were histologically very similar. Oocytes were classified into five development stages, and specific characteristics were observed: mature oocytes with thin chorion, pedicel cells arranged forming an epithelium with two or more oocytes attached by the same structure, and a large number of oocytes in the process of reabsorption. Copyright © 2011 Elsevier GmbH. All rights reserved.

Motility contrast imaging of live porcine cumulus-oocyte complexes

NASA Astrophysics Data System (ADS)

An, Ran; Turek, John; Machaty, Zoltan; Nolte, David

2013-02-01

Freshly-harvested porcine oocytes are invested with cumulus granulosa cells in cumulus-oocyte complexes (COCs). The cumulus cell layer is usually too thick to image the living oocyte under a conventional microscope. Therefore, it is difficult to assess the oocyte viability. The low success rate of implantation is the main problem for in vitro fertilization. In this paper, we demonstrate our dynamic imaging technique called motility contrast imaging (MCI) that provides a non-invasive way to monitor the COCs before and after maturation. MCI shows a change of intracellular activity during oocyte maturation, and a measures dynamic contrast between the cumulus granulosa shell and the oocytes. MCI also shows difference in the spectral response between oocytes that were graded into quality classes. MCI is based on shortcoherence digital holography. It uses intracellular motility as the endogenous imaging contrast of living tissue. MCI presents a new approach for cumulus-oocyte complex assessment.

Ethical issues in transnational "mail order" oocyte donation.

PubMed

Heng, B C

2006-12-01

The rising demand for donor oocytes in developed countries has led to what is referred to as transnational or international oocyte donation, or the outsourcing of oocyte donation to poorer countries. In a further twist, frozen sperm from a recipient's partner can also be mailed to a foreign clinic to fertilize donor oocytes, and the resulting embryos are mailed back, cryopreserved, for transfer to the recipient. Among the numerous ethical concerns raised by this practice of mail order oocyte donation, the most obvious are that underprivileged women from poorer countries are often exploited; fertility physicians from richer counties abdicate responsibility for the welfare of donors; and responsibility could become an issue of contention if transmission of disease to the oocyte recipient or congenital defects in offspring born from such oocyte donation were to occur. Moreover, savings from utilizing donors from poorer countries ought to be shared with oocyte recipients.

Effect of open pulled straw (OPS) vitrification on the fertilisation rate and developmental competence of porcine oocytes.

PubMed

Varga, Erika; Gardón, J C; Papp, Agnes Bali

2006-03-01

Freezing technologies are very important to preserve gametes and embryos of animals with a good pedigree or those having high genetic value. The aim of this work was to compare immature and in vitro matured porcine oocytes regarding their morphology and ability to be fertilised after vitrification by the open pulled straw (OPS) method. In four experiments 830 oocytes were examined. To investigate the effect of cumulus cells on oocyte survival after OPS vitrification, both denuded and cumulus-enclosed oocytes were vitrified at the germinal vesicle (GV) stage, then after vitrification they were matured in vitro. Besides, in vitro matured oocytes surrounded with a cumulus and those without a cumulus were also vitrified. The survival of oocytes was evaluated by their morphology. After in vitro fertilisation the rates of oocytes penetrated by spermatozoa were compared. Our results suggest that the vitrification/warming procedure is the most effective in cumulus-enclosed oocytes (22.35 +/- 1.75%). There was no difference between the order of maturation and vitrification in cumulus-enclosed oocytes, which suggests the importance of cumulus cells in protecting the viability of oocytes during cryopreservation.

The current challenges to efficient immature oocyte cryopreservation.

PubMed

Brambillasca, Fausta; Guglielmo, Maria Cristina; Coticchio, Giovanni; Mignini Renzini, Mario; Dal Canto, Mariabeatrice; Fadini, Rubens

2013-12-01

Oocyte cryopreservation represents an important tool for assisted reproductive technology. It offers the opportunity to preserve fertility in women at risk of loss of the ovarian function for various pathologies. It also represents a treatment alternative for couples that cannot benefit from embryo cryopreservation because of moral, religious, or legal constrains. On the other hand, in vitro oocyte maturation has a range of applications. It can be applied in patients with a contraindication to ovarian stimulation to prevent ovarian hyperstimulation syndrome or to eliminate the risk of stimulation of hormone-sensitive tumours in cancer patients. However, while mature oocyte cryopreservation has found wide-spread application and oocyte in vitro maturation has a place for the treatment of specific clinical conditions, data on the efficiency of freezing of immature or in vitro matured oocytes are poorer. In this review we will focus on the combination of oocyte in vitro maturation with oocyte cryopreservation with particular emphasis on the biological implications of the cryopreservation of immature or in vitro matured oocytes. The two cryopreservation approaches, slow freezing and vitrification, will be discussed in relation to possible cryodamage occurring to subcellular structures of the oocyte and the functional interaction between oocyte and cumulus cells.

In vitro embryo production in goats: Slaughterhouse and laparoscopic ovum pick up-derived oocytes have different kinetics and requirements regarding maturation media.

PubMed

Souza-Fabjan, Joanna Maria G; Locatelli, Yann; Duffard, Nicolas; Corbin, Emilie; Touzé, Jean-Luc; Perreau, Christine; Beckers, Jean François; Freitas, Vicente José F; Mermillod, Pascal

2014-05-01

A total of 3427 goat oocytes were used in this study to identify possible differences during in vitro embryo production from slaughterhouse or laparoscopic ovum pick up (LOPU) oocytes. In experiment 1, one complex, one semi-defined, and one simplified IVM media were compared using slaughterhouse oocytes. In experiment 2, we checked the effect of oocyte origin (slaughterhouse or LOPU) on the kinetics of maturation (18 vs. 22 vs. 26 hours) when submitted to semi-defined or simplified media. In experiment 3, we determined the differences in embryo development between slaughterhouse and LOPU oocytes when submitted to both media and then to IVF or parthenogenetic activation (PA). Embryos from all groups were vitrified, and their viability evaluated in vitro after thawing. In experiment 1, no difference (P > 0.05) was detected among treatments for maturation rate (metaphase II [MII]; 88% on average), cleavage (72%), blastocyst from the initial number of cumulus oocyte complexes (46%) or from the cleaved ones (63%), hatching rate (69%), and the total number of blastomeres (187). In experiment 2, there was no difference of MII rate between slaughterhouse oocytes cultured for 18 or 22 hours, whereas the MII rate increased significantly (P < 0.05) between 18 and 22 hours for LOPU oocytes in the simplified medium. Moreover, slaughterhouse oocytes cultured in simplified medium matured significantly faster than LOPU oocytes at 18 and 22 hours (P < 0.05). In experiment 3, cleavage rate was significantly greater (P < 0.001) in all four groups of embryos produced by PA than IVF. Interestingly, PA reached similar rates for slaughterhouse oocytes cultured in both media, but improved (P < 0.05) the cleavage rate of LOPU oocytes. Slaughterhouse oocytes had acceptable cleavage rate after IVF (∼67%), whereas LOPU oocytes displayed a lower one (∼38%), in contrast to cleavage after PA. The percentage of blastocysts in relation to cleaved embryos was not affected by the origin of the oocytes (P > 0.05). Therefore, slaughterhouse oocytes developed a greater proportion of blastocysts than LOPU ones, expressed as the percentage of total cumulus oocyte complexes entering to IVM. Vitrified-thawed blastocysts presented similar survival and hatching rates between the oocyte origin, media, or method of activation. In conclusion, slaughterhouse and LOPU derived oocytes may have different IVM kinetics and require different IVM and IVF conditions. Although the IVM and IVF systems still need improvements to enhance embryo yield, the in vitro development step is able to generate good quality embryos from LOPU-derived oocytes. Copyright © 2014 Elsevier Inc. All rights reserved.

Storage time does not modify the gene expression profile of cryopreserved human metaphase II oocytes.

PubMed

Stigliani, Sara; Moretti, Stefano; Anserini, Paola; Casciano, Ida; Venturini, Pier Luigi; Scaruffi, Paola

2015-11-01

Does storage time have any impact on the transcriptome of slowly frozen cryopreserved human metaphase II (MII) oocytes? The length of cryostorage has no effect on the gene expression profile of human MII oocytes. Oocyte cryopreservation is a widely used technique in IVF for storage of surplus oocytes, as well as for fertility preservation (i.e. women undergoing gonadotoxic therapies) and oocyte donation programs. Although cryopreservation has negative impacts on oocyte physiology and it is associated with decrease of transcripts, no experimental data about the effect of storage time on the oocyte molecular profile are available to date. This study included 27 women, ≤38 years aged, without any ovarian pathology, undergoing IVF treatment. Surplus MII oocytes were donated after written informed consent. A total of 31 non-cryopreserved oocytes and 68 surviving slow-frozen/rapid-thawed oocytes (32 oocytes cryostored for 3 years and 36 cryostored for 6 years) were analyzed. Pools of ≈10 oocytes for each group were prepared. Total RNA was extracted from each pool, amplified, labeled and hybridized on oligonucleotide microarrays. Analyses were performed by R software using the limma package. Comparison of gene expression profiles between surviving thawed oocytes after 3 and 6 years of storage in liquid nitrogen found no differently expressed genes. The expression profiles of cryopreserved MII oocytes significantly differed from those of non-cryopreserved oocytes in 107 probe sets corresponding to 73 down-regulated and 29 up-regulated unique transcripts. Gene Ontology analysis by DAVID bioinformatics resource disclosed that cryopreservation deregulates genes involved in oocyte function and early embryo development, such as chromosome organization, RNA splicing and processing, cell cycle, cellular response to DNA damage and to stress, DNA repair, calcium ion binding, malate dehydrogenase activity and mitochondrial activity. Among the probes significantly up-regulated in cryopreserved oocytes, two corresponded to ovary-specific expressed large intergenic noncoding (linc)RNAs. Data validation in a larger cohort of samples would be beneficial, although we applied stringent criteria for gene selection (fold-change >3 or <1/3 and FDR < 0.1). Further research should be undertaken to verify experimentally that the length of cryostorage has no effect on gene expression profile of vitrified/warmed MII oocytes, as well as to include in analyses 'older' frozen oocytes. Confirmation that the length of storage does not alter the gene expression profile of frozen oocytes is noteworthy for the safety issue of long-term oocyte banking, i.e. fertility preservation, gamete donation. This study was supported by a grant of the Italian Ministry of Health (CCM 2012) and by Ferring Pharmaceutical company. The authors have no conflicts of interest to declare. © The Author 2015. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Effect of holding equine oocytes in meiosis inhibitor-free medium before in vitro maturation and of holding temperature on meiotic suppression and mitochondrial energy/redox potential.

PubMed

Martino, Nicola A; Dell'Aquila, Maria E; Filioli Uranio, Manuel; Rutigliano, Lucia; Nicassio, Michele; Lacalandra, Giovanni M; Hinrichs, Katrin

2014-10-11

Evaluation of mitochondrial function offers an alternative to evaluate embryo development for assessment of oocyte viability, but little information is available on the relationship between mitochondrial and chromatin status in equine oocytes. We evaluated these parameters in immature equine oocytes either fixed immediately (IMM) or held overnight in an Earle's/Hank's' M199-based medium in the absence of meiotic inhibitors (EH treatment), and in mature oocytes. We hypothesized that EH holding may affect mitochondrial function and that holding temperature may affect the efficiency of meiotic suppression. Experiment 1 - Equine oocytes processed immediately or held in EH at uncontrolled temperature (22 to 27°C) were evaluated for initial chromatin configuration, in vitro maturation (IVM) rates and mitochondrial energy/redox potential. Experiment 2 - We then investigated the effect of holding temperature (25°C, 30°C, 38°C) on initial chromatin status of held oocytes, and subsequently repeated mitochondrial energy/redox assessment of oocytes held at 25°C vs. immediately-evaluated controls. EH holding at uncontrolled temperature was associated with advancement of germinal vesicle (GV) chromatin condensation and with meiotic resumption, as well as a lower maturation rate after IVM. Holding did not have a significant effect on mitochondrial distribution within chromatin configurations. Independent of treatment, oocytes having condensed chromatin had a significantly higher proportion of perinuclear/pericortical mitochondrial distribution than did other GV configurations. Holding did not detrimentally affect oocyte energy/redox parameters in viable GV-stage oocytes. There were no significant differences in chromatin configuration between oocytes held at 25°C and controls, whereas holding at higher temperature was associated with meiosis resumption and loss of oocytes having the condensed chromatin GV configuration. Holding at 25°C was not associated with progression of mitochondrial distribution pattern and there were no significant differences in oocyte energy/redox parameters between these oocytes and controls. Mitochondrial distribution in equine GV-stage oocytes is correlated with chromatin configuration within the GV. Progression of chromatin configuration and mitochondrial status during holding are dependent on temperature. EH holding at 25°C maintains meiotic arrest, viability and mitochondrial potential of equine oocytes. This is the first report on the effects of EH treatment on oocyte mitochondrial energy/redox potential.

Identification of Maturation-Specific Proteins by Single-Cell Proteomics of Human Oocytes

PubMed Central

Virant-Klun, Irma; Leicht, Stefan; Hughes, Christopher; Krijgsveld, Jeroen

2016-01-01

Oocytes undergo a range of complex processes via oogenesis, maturation, fertilization, and early embryonic development, eventually giving rise to a fully functioning organism. To understand proteome composition and diversity during maturation of human oocytes, here we have addressed crucial aspects of oocyte collection and proteome analysis, resulting in the first proteome and secretome maps of human oocytes. Starting from 100 oocytes collected via a novel serum-free hanging drop culture system, we identified 2,154 proteins, whose function indicate that oocytes are largely resting cells with a proteome that is tailored for homeostasis, cellular attachment, and interaction with its environment via secretory factors. In addition, we have identified 158 oocyte-enriched proteins (such as ECAT1, PIWIL3, NLRP7)1 not observed in high-coverage proteomics studies of other human cell lines or tissues. Exploiting SP3, a novel technology for proteomic sample preparation using magnetic beads, we scaled down proteome analysis to single cells. Despite the low protein content of only ∼100 ng per cell, we consistently identified ∼450 proteins from individual oocytes. When comparing individual oocytes at the germinal vesicle (GV) and metaphase II (MII) stage, we found that the Tudor and KH domain-containing protein (TDRKH) is preferentially expressed in immature oocytes, while Wee2, PCNA, and DNMT1 were enriched in mature cells, collectively indicating that maintenance of genome integrity is crucial during oocyte maturation. This study demonstrates that an innovative proteomics workflow facilitates analysis of single human oocytes to investigate human oocyte biology and preimplantation development. The approach presented here paves the way for quantitative proteomics in other quantity-limited tissues and cell types. Data associated with this study are available via ProteomeXchange with identifier PXD004142. PMID:27215607

Mouse oocytes fertilised by ICSI during in vitro maturation retain the ability to be activated after refertilisation in metaphase II and can generate Ca2+ oscillations

PubMed Central

Jędrusik, Agnieszka; Ajduk, Anna; Pomorski, Paweł; Maleszewski, Marek

2007-01-01

Background At fertilisation, mammalian oocytes are activated by oscillations of intracellular Ca2+ ([Ca2+]i). Phospholipase Cζ, which is introduced by fertilising spermatozoon, triggers [Ca2+]i oscillations through the generation of inositol 1,4,5-triphosphate (IP3), which causes Ca2+ release by binding to IP3 receptors located on the endoplasmic reticulum (ER) of the oocyte. Ability to respond to this activating stimulus develops during meiotic maturation of the oocyte. Here we examine how the development of this ability is perturbed when a single spermatozoon is introduced into the oocyte prematurely, i.e. during oocyte maturation. Results Mouse oocytes during maturation in vitro were fertilised by ICSI (intracytoplasmic sperm injection) 1 – 4 h after germinal vesicle break-down (GVBD) and were subsequently cultured until they reached metaphase II (MII) stage. At MII stage they were fertilised in vitro for the second time (refertilisation). We observed that refertilised oocytes underwent activation with similar frequency as control oocytes, which also went through maturation in vitro, but were fertilised only once at MII stage (87% and 93%, respectively). Refertilised MII oocytes were able to develop [Ca2+]i oscillations in response to penetration by spermatozoa. We found however, that they generated a lower number of transients than control oocytes. We also showed that the oocytes, which were fertilised during maturation had a similar level of MPF activity as control oocytes, which were not subjected to ICSI during maturation, but had reduced level of IP3 receptors. Conclusion Mouse oocytes, which were experimentally fertilised during maturation retain the ability to generate repetitive [Ca2+]i transients, and to be activated after completion of maturation. PMID:17584490

Meiotic competence of equine oocytes and pronucleus formation after intracytoplasmic sperm injection (ICSI) as related to granulosa cell apoptosis.

PubMed

Dell'Aquila, Maria Elena; Albrizio, Maria; Maritato, Filippo; Minoia, Paolo; Hinrichs, Katrin

2003-06-01

Follicle atresia and granulosa cell apoptosis may be related to oocyte meiotic and developmental competence. We analyzed the relationships among granulosa cell apoptosis, initial cumulus morphology, oocyte nuclear maturation in vitro, and pronucleus formation after intracytoplasmic sperm injection (ICSI) in the horse. For each follicle, the size was measured and granulosa cells were used for DNA laddering analysis. Oocytes were evaluated for cumulus morphology, cultured for in vitro maturation, and submitted to ICSI. Apoptosis was categorized as absent, intermediate, or advanced according to the relative concentrations of two DNA fragments at 900 and 360 base pairs (bp). In 98 oocyte-follicle pairs, 52 oocytes were classified as expanded (Exp), 39 as compact (Cp), and 7 as having a partial (P) cumulus. Advanced apoptosis was detected in 55% (54/98) of follicles; 37% (36/98) of follicles showed an intermediate level of apoptosis; and 8 follicles (8%) were nonapoptotic. Follicle size was not significantly correlated with granulosa cell apoptosis (P > 0.05). Significantly more Exp than Cp oocytes originated from follicles with advanced apoptosis (P < 0.001). The proportion of oocytes maturing in vitro was significantly higher in oocytes issuing from apoptotic follicles than in oocytes issuing from healthy follicles (P < 0.05). The proportion of normally (two pronuclei) or abnormally fertilized oocytes (one or greater than two pronuclei, or partially decondensed sperm) did not differ in relation to granulosa cell apoptosis. We conclude that, in the mare, granulosa cell apoptosis is related to cumulus expansion and an increase in oocyte meiotic competence but has no effect on the proportion of meiotically competent oocytes that activate after ICSI. These results provide selection criteria for horse oocytes used in assisted reproductive techniques so that embryo production may be maximized.

Holding immature equine oocytes in the absence of meiotic inhibitors: effect on germinal vesicle chromatin and blastocyst development after intracytoplasmic sperm injection.

PubMed

Choi, Y H; Love, L B; Varner, D D; Hinrichs, K

2006-09-01

Holding immature oocytes before the onset of maturation simplifies oocyte transport and aids in scheduling later manipulations. We report here a method for holding equine oocytes in the absence of meiotic inhibitors. In Experiment 1, immature oocytes with expanded cumuli were cultured at 38.2 degrees C in medium containing cycloheximide, or were held at room-temperature in M199 with Hanks' salts, for 16-18 h before maturation. Control oocytes were matured immediately after recovery. Oocytes were fertilized by intracytoplasmic sperm injection and cultured for 4d. Embryo development was not different among treatments. In Experiment 2, oocytes were treated as in Experiment 1, but embryos were cultured for 7.5d. Blastocyst development was significantly lower in the cycloheximide-treated group than in controls (7% versus 30%) with the room-temperature group intermediate (16%). In Experiment 3, oocytes were cultured at 38.2 degrees C in medium containing roscovitine, or were held at room temperature in sealed glass vials in a mixture of 40% M199 with Earle's salts, 40% M199 with Hanks' salts, and 20% FBS (EH treatment) for 16-18 h, before maturation, sperm injection, and embryo culture for 7.5d. Blastocyst development of oocytes in the EH treatment was significantly higher than that for roscovitine-treated oocytes (34% versus 12%), but not significantly different from that for controls (25%). Oocytes in the EH treatment did not mature during holding (70% germinal vesicle stage after 18 h holding). Whereas culture with cycloheximide or roscovitine of equine oocytes with expanded cumuli reduced subsequent blastocyst formation, these oocytes could be held in a modified M199 at room temperature overnight without adverse affecting meiotic or developmental competence.

Role of arachidonic acid cascade in Rhinella arenarum oocyte maturation.

PubMed

Ortiz, Maria Eugenia; Arias-Torres, Ana Josefina; Zelarayán, Liliana Isabel

2015-08-01

There are no studies that document the production of prostaglandins (PGs) or their role in Rhinella arenarum oocyte maturation. In this study, we analysed the effect of arachidonic acid (AA) and prostaglandins (PGs) on maturation, activation and pronuclear formation in R. arenarum oocytes. Our results demonstrated that AA was capable of inducing maturation in time-dependent and dose-dependent manner. Arachidonic acid-induced maturation was inhibited by indomethacin. PGs from AA hydrolysis, such as prostaglandin F2α (PGF2α) and, to a lesser extent, PGE2, induced meiosis resumption. Oocyte maturation in response to PGF2α was similar to that produced by progesterone (P4). Oocyte response to PGE1 was scarce. Rhinella arenarum oocyte PGF2α-induced maturation showed seasonal variation. From February to June, oocytes presented low sensitivity to PGF2α. In following periods, this response increased until a maximum was reached during October to January, a close temporal correlation with oocyte response to P4 being observed. The effect of PGF2α on maturation was verified by analysing the capacity of oocytes to activate and form pronuclei after being injected with homologous sperm. The cytological analysis of activated oocytes demonstrated the absence of cortical granules in oocytes, suggesting that PGF2α induces germinal vesicle breakdown (GVBD) and meiosis resumption up to metaphase II. In turn, oocytes matured by the action of PGF2α were able to form pronuclei after fertilization in a similar way to oocyte maturated by P4. In microinjection of mature cytoplasm experiments, the transformation of pre-maturation promoting factor (pre-MPF) to MPF was observed when oocytes were treated with PGF2α. In summary, our results illustrated the participation of the AA cascade and its metabolites in maturation, activation and pronuclei formation in R. arenarum.

An oocyte-specific ELAVL2 isoform is a translational repressor ablated from meiotically competent antral oocytes

PubMed Central

Chalupnikova, Katerina; Solc, Petr; Sulimenko, Vadym; Sedlacek, Radislav; Svoboda, Petr

2014-01-01

At the end of the growth phase, mouse antral follicle oocytes acquire full developmental competence. In the mouse, this event is marked by the transition from the so-called non-surrounded nucleolus (NSN) chromatin configuration into the transcriptionally quiescent surrounded nucleolus (SN) configuration, which is named after a prominent perinucleolar condensed chromatin ring. However, the SN chromatin configuration alone is not sufficient for determining the developmental competence of the SN oocyte. There are additional nuclear and cytoplamic factors involved, while a little is known about the changes occurring in the cytoplasm during the NSN/SN transition. Here, we report functional analysis of maternal ELAVL2 an AU-rich element binding protein. Elavl2 gene encodes an oocyte-specific protein isoform (denoted ELAVL2°), which acts as a translational repressor. ELAVL2° is abundant in fully grown NSN oocytes, is ablated during the NSN/SN transition and remains low during the oocyte-to-embryo transition (OET). ELAVL2° overexpression during meiotic maturation causes errors in chromosome segregation, indicating the significance of naturally reduced ELAVL2° levels in SN oocytes. On the other hand, during oocyte growth, prematurely reduced Elavl2 expression results in lower yields of fully grown and meiotically matured oocytes, suggesting that Elavl2 is necessary for proper oocyte maturation. Moreover, Elavl2 knockdown showed stimulating effects on translation in fully grown oocytes. We propose that ELAVL2 has an ambivalent role in oocytes: it functions as a pleiotropic translational repressor in efficient production of fully grown oocytes, while its disposal during the NSN/SN transition contributes to the acquisition of full developmental competence. PMID:24553115

Maturation capacity, morphology and morphometric assessment of human immature oocytes after vitrification and in-vitro maturation

PubMed Central

Nazari, Saeedeh; Khalili, Mohammad Ali; Esmaielzadeh, Forouzan; Mohsenzadeh, Mehdi

2011-01-01

Background: In general, 15% of oocytes collected in ART cycles are immature. These oocytes may be cryopreserved further for use in in-vitro maturation (IVM) program. Objective: The aim of this study was to determine maturation capacity, morphometric parameters and morphology of human immature oocytes in both fresh IVM (fIVM) and vitrified-IVM (vIVM) oocytes. Materials and Methods: 93 women who underwent controlled ovarian stimulation for ART were included. The immature oocytes (n=203) were divided into two groups: the first group (n=101) directly matured in vitro; and the second group (n=102) first vitrified, then matured in vitro. All oocytes underwent IVM in Ham’s F10 supplemented with LH+FSH and human follicular fluid. After 48h of incubation, the oocyte maturation rates, as well as morphometric and morphologic characteristics were assessed using cornus imaging and were compared. Results: Oocyte maturation rates were reduced in vIVM, (40.4%), in comparison with fIVM (59.4%, p<0.001). Following morphometric assessment, there was no difference in the mean oocyte diameters (µm) between fIVM and vIVM, 156.3±6.8 and 154.07±9.9, respectively. Other parameters of perimeters, egg areas, as well as oocyte and ooplasm volumes were similar in two groups. In addition, more morphologic abnormalities, such as, vacuole, and dark oocyte were observed in vIVM oocytes. Conclusion: fIVM was more successful than vIVM groups. No statistical differences were noticed in morphometry assessment in two groups. This suggests that morphometric parameters can not be applied as prognosis factor in oocyte maturation outcome in IVM program. PMID:26396566

Identification of Maturation-Specific Proteins by Single-Cell Proteomics of Human Oocytes.

PubMed

Virant-Klun, Irma; Leicht, Stefan; Hughes, Christopher; Krijgsveld, Jeroen

2016-08-01

Oocytes undergo a range of complex processes via oogenesis, maturation, fertilization, and early embryonic development, eventually giving rise to a fully functioning organism. To understand proteome composition and diversity during maturation of human oocytes, here we have addressed crucial aspects of oocyte collection and proteome analysis, resulting in the first proteome and secretome maps of human oocytes. Starting from 100 oocytes collected via a novel serum-free hanging drop culture system, we identified 2,154 proteins, whose function indicate that oocytes are largely resting cells with a proteome that is tailored for homeostasis, cellular attachment, and interaction with its environment via secretory factors. In addition, we have identified 158 oocyte-enriched proteins (such as ECAT1, PIWIL3, NLRP7)(1) not observed in high-coverage proteomics studies of other human cell lines or tissues. Exploiting SP3, a novel technology for proteomic sample preparation using magnetic beads, we scaled down proteome analysis to single cells. Despite the low protein content of only ∼100 ng per cell, we consistently identified ∼450 proteins from individual oocytes. When comparing individual oocytes at the germinal vesicle (GV) and metaphase II (MII) stage, we found that the Tudor and KH domain-containing protein (TDRKH) is preferentially expressed in immature oocytes, while Wee2, PCNA, and DNMT1 were enriched in mature cells, collectively indicating that maintenance of genome integrity is crucial during oocyte maturation. This study demonstrates that an innovative proteomics workflow facilitates analysis of single human oocytes to investigate human oocyte biology and preimplantation development. The approach presented here paves the way for quantitative proteomics in other quantity-limited tissues and cell types. Data associated with this study are available via ProteomeXchange with identifier PXD004142. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Fibroblast growth factor 10 enhances bovine oocyte maturation and developmental competence in vitro.

PubMed

Zhang, Kun; Hansen, Peter J; Ealy, Alan D

2010-12-01

The ability of oocytes to resume meiosis, become fertilized, and generate viable pregnancies is controlled during folliculogenesis by several endocrine and paracrine factors. The aim of this work is to determine whether fibroblast growth factor 10 (FGF10) is an oocyte competent factor. Transcripts for each of the four FGF receptor types (FGFR) were present in cumulus and oocytes after their extraction from the follicles. FGFR1 transcripts predominated in cumulus cells whereas FGFR2 was most abundant in oocytes. Exposing the cumulus-oocyte complexes to FGF10 during in vitro maturation did not affect cleavage rates, but increases (P<0.05) in the percentage of embryos at the 8-16-cell stage on day 3 and at the blastocyst stage on day 7, which were evident in FGF10-supplemented oocytes. The progression of oocytes through meiosis and cumulus expansion was increased (P<0.05) by FGF10. The importance of the endogenous sources of FGFs was examined by adding anti-FGF10 IgG during oocyte maturation. Blocking endogenous FGF10 activity decreased (P<0.05) the percentage of oocytes developing into blastocysts and limited (P<0.05) cumulus expansion. Expression profiles of putative cumulus and oocyte competency markers were examined for their involvement in FGF10-mediated responses. FGF10 influenced the expression of CTSB and SPRY2 in cumulus cells and BMP15 in oocytes. In summary, this work provides new insight into the importance of FGFRs and locally derived FGF10 during oocyte maturation in cattle. Its subsequent impact on in vitro embryo development implicates it as a noteworthy oocyte competent factor.

Ultrastructural Studies on Oocyte Development and Vitellogenesis associated with Follicle Cells in Female Scapharca subcrenata (Pelecypoda: Arcidae) in Western Korea

PubMed Central

Kim, Sung Han

2016-01-01

Ultrastructural studies on oocyte development and vitellogenesis in oocytes, and the functions of follicle cells during oogenesis and oocyte degeneration were investigated to clarifyb the reproductive mechanism on vitellogenesis of Scapharca subcrenata using electron microscope observations. In this study, vitellogenesis during oogenesis in the oocytes occured by way of autosynthesis and heterosynthesis. Of two processes of vitellogenesis during oogenesis, the process of endogenous autosynthesis involved the combined activity of the Golgi complex, mitochondria and rough endoplasmic reticulum. However, the process of exogenous heterosynthesis involved endocytotic incorporation of extraovarian precursors at the basal region of the oolema of the early vitellogenic oocytes before the formation of the vitelline coat. In this study, follicle cells, which attached to the previtellogenic and vitellogenic oocytes, were easily found. In particular, the follicle cells were involved in the development of previtellogenic oocytes by the supply of nutrients, and vitellogenesis in the early and late vitellogenic oocytes by endocytosis of yolk precursors. Based on observations of follicle cells attached to degenerating oocytes after spawning, follicles of this species are involved in lysosomal induction of oocyte degeneration for the resorption phagosomes (phagolysosomes) in the cytoplasm for nutrient storage, as seen in other bivalves. In this study, the functions of follicle cells can accumulate reserves of lipid granules and glycogen particles for vitellogenesis from degenerating oocytes after spawning. PMID:27796004

Influence of co-culture with denuded oocytes during in vitro maturation on fertilization and developmental competence of cumulus-enclosed porcine oocytes in a defined system.

PubMed

Appeltant, Ruth; Somfai, Tamás; Kikuchi, Kazuhiro; Maes, Dominiek; Van Soom, Ann

2016-04-01

Co-culture of cumulus-oocyte complexes (COCs) with denuded oocytes (DOs) during in vitro maturation (IVM) was reported to improve the developmental competence of oocytes via oocyte-secreted factors in cattle. The aim of the present study was to investigate if addition of DOs during IVM can improve in vitro fertilization (IVF) and in vitro culture (IVC) results for oocytes in a defined in vitro production system in pigs. The maturation medium was porcine oocyte medium supplemented with gonadotropins, dbcAMP and β-mercaptoethanol. Cumulus-oocyte complexes were matured without DOs or with DOs in different ratios (9 COC, 9 COC+16 DO and 9 COC+36 DO). Consequently; oocytes were subjected to IVF as intact COCs or after denudation to examine if DO addition during IVM would affect cumulus or oocyte properties. After fertilization, penetration and normal fertilization rates of zygotes were not different between all tested groups irrespective of denudation before IVF. When zygotes were cultured for 6 days, no difference could be observed between all treatment groups in cleavage rate, blastocyst rate and cell number per blastocyst. In conclusion, irrespective of the ratio, co-culture with DOs during IVM did not improve fertilization parameters and embryo development of cumulus-enclosed porcine oocytes in a defined system. © 2015 Japanese Society of Animal Science.

Controlled loading of cryoprotectants (CPAs) to oocyte with linear and complex CPA profiles on a microfluidic platform.

PubMed

Heo, Yun Seok; Lee, Ho-Joon; Hassell, Bryan A; Irimia, Daniel; Toth, Thomas L; Elmoazzen, Heidi; Toner, Mehmet

2011-10-21

Oocyte cryopreservation has become an essential tool in the treatment of infertility by preserving oocytes for women undergoing chemotherapy. However, despite recent advances, pregnancy rates from all cryopreserved oocytes remain low. The inevitable use of the cryoprotectants (CPAs) during preservation affects the viability of the preserved oocytes and pregnancy rates either through CPA toxicity or osmotic injury. Current protocols attempt to reduce CPA toxicity by minimizing CPA concentrations, or by minimizing the volume changes via the step-wise addition of CPAs to the cells. Although the step-wise addition decreases osmotic shock to oocytes, it unfortunately increases toxic injuries due to the long exposure times to CPAs. To address limitations of current protocols and to rationally design protocols that minimize the exposure to CPAs, we developed a microfluidic device for the quantitative measurements of oocyte volume during various CPA loading protocols. We spatially secured a single oocyte on the microfluidic device, created precisely controlled continuous CPA profiles (step-wise, linear and complex) for the addition of CPAs to the oocyte and measured the oocyte volumetric response to each profile. With both linear and complex profiles, we were able to load 1.5 M propanediol to oocytes in less than 15 min and with a volumetric change of less than 10%. Thus, we believe this single oocyte analysis technology will eventually help future advances in assisted reproductive technologies and fertility preservation.

Effects of cilostamide and/or forskolin on the meiotic resumption and development competence of growing ovine oocytes selected by brilliant cresyl blue staining.

PubMed

Azari-Dolatabad, Nima; Rahmani, H R; Hajian, M; Ostadhosseini, S; Hosseini, S M; Nasr-Esfahani, M H

2016-05-01

The relevance of low developmental competence of in vitro-matured oocyte to the incomplete/delayed cytoplasmic maturation, and the heterogeneity of retrieved oocytes is well established in several species. A short phase of prematuration culture was used to allow better oocyte cytoplasmic maturation. The preselection of growing and fully grown oocytes has been proposed to improve developmental competency. This study investigated the effects of phosphodiesterase type 3-specific inhibitor, cilostamide, and adenylate cyclase activator, forskolin, on the resumption of meiosis and developmental competence of growing ovine oocytes selected by brilliant cresyl blue (BCB) staining. Results indicate that cilostamide, forskolin, and their combination significantly (P < 0.05) increased the percentage of growing (BCB-) oocytes maintained at the germinal vesicle stage. However, only forskolin significantly (P < 0.05) increased the yield and quality of blastocysts derived from BCB- oocytes compared with non-BCB-treated oocytes. We conclude that a short prematuration culture with forskolin may improve the in vitro developmental competency of growing oocytes in ovine. Copyright © 2016 Elsevier Inc. All rights reserved.

Incapacity of Response to Disulfide-Reducing Agent in Triton X-100-Treated Oocytes of Starfish, Asterina pectinifera

NASA Astrophysics Data System (ADS)

Mita, Masatoshi

2005-04-01

Resumption of meiosis in starfish oocytes is induced by the natural maturation-inducing hormone, 1-methyladenine (1-MeAde). Oocyte maturation is also induced by the disulfide-reducing agent, dithiothreitol (DTT). Previous studies have shown that 1-MeAde controls meiosis by interacting with its receptors, which are located exclusively on oocyte plasma membrane. However, little is known about the mechanism of oocyte maturation induced by DTT. Thus, this study examined whether DTT interacts with 1-MeAde receptors to induce oocyte maturation. When oocytes were treated with Triton X-100, they failed to respond to 1-MeAde and DTT. Although the Triton X-100-treated oocytes recovered the capacity to respond to 1-MeAde during incubation in seawater, they remained unresponsive to DTT during seawater incubations. These results suggest that DTT does not interact with 1-MeAde receptors to induce oocyte maturation in starfish. It is possible that a protein essential for mediating DTT-induced maturation is eliminated from the oocytes surface following Triton X-100 treatment.

Treatment with acetyl-l-carnitine during in vitro maturation of buffalo oocytes improves oocyte quality and subsequent embryonic development.

PubMed

Xu, Hui-Yan; Yang, Xiao-Gan; Lu, Sheng-Sheng; Liang, Xing-Wei; Lu, Yang-Qing; Zhang, Ming; Lu, Ke-Huan

2018-06-01

Oocyte quality is one of the important factors in female fertility, in vitro maturation (IVM), and subsequent embryonic development. In the present study, we assessed whether acetyl-l-carnitine (ALC) supplementation during in vitro maturation of buffalo oocytes could improve oocyte quality and subsequent embryonic development. To determine the optimal level of ALC supplementation, we matured cumulus-oocyte complexes in maturation medium supplemented with 0, 2.5, and 5 mM ALC. The oocytes with a polar body were selected for parthenogenetic activation (PA) and in vitro fertilization (IVF). We found that oocytes matured in 2.5 mM ALC had significantly higher PA blastocyst rate (P < 0.05) and blastocyst cell number than those of unsupplemented oocytes (P < 0.05) and a significantly higher IVF blastocyst rate than that of oocytes matured in 5 mM ALC (P < 0.05). In all further experiments, we supplemented the maturation medium with 2.5 mM ALC. We then tested whether ALC supplementation could improve various markers of oocytes and cumulus cells. We compared cell proliferation; concentrations of reactive oxygen species (ROS), intracellular ATP, estradiol, and progesterone; mitochondrial distribution; mitochondrial DNA copy number (mtDNA); and expression levels of four genes encoding oocyte-derived factors (GDF9, BMP15) and steroid hormones (StAR, P450scc) between the supplemented and unsupplemented oocytes and cumulus cells. Cumulus cells matured with ALC supplementation were more prolific than those matured without ALC supplementation (P < 0.05). Oocytes treated with ALC had lower concentrations of intracellular ROS (P < 0.05) and a higher rate of diffuse mitochondrial distributions (P < 0.05) than those of untreated oocytes. Additionally, the mtDNA was higher in the ALC-treated oocytes (P < 0.05) and cumulus cells (P < 0.05) than that in the untreated cells. The ALC-treated maturation medium had a higher postmaturation concentration of estradiol than that of the untreated medium (P < 0.05). Finally, the gene expression levels of P450scc and GDF9 were greater in ALC-treated oocytes and cumulus cells than those in untreated cells (P < 0.05). Therefore, in buffalo, our results suggest that ALC affects mitochondrial function, regulates oocyte-derived paracrine factors, and increases the production of steroid hormones, leading to increased quality of matured oocytes and improved embryonic development in vitro. Copyright © 2018 Elsevier Inc. All rights reserved.

Cortical granule exocytosis in Bufo arenarum oocytes matured in vitro.

PubMed

Oterino, J; Sanchez Toranzo, G; Zelarayán, L; Valz-Gianinet, J N; Bühler, M I

2001-08-01

Denuded Bufo arenarum oocytes matured in vitro by progesterone treatment exhibited abnormal segmentation due to the penetration of more than one sperm. These oocytes were able to respond to activation stimuli and exhibited the external signs characteristic of activation. However, the prevention of polyspermy was not effective in these oocytes, which exhibited numerous sperm in their cytoplasm. The aim of this work was to analyse the cortical reaction in polyspermic Bufo arenarum oocytes matured in vitro. The result indicate that the cortical reaction of these oocytes seems to occur with a chronological sequence similar to that described for ovoposited oocytes of this species. In addition, when, 1 min after pricking, cortical granule exocytosis occurred, the oocytes became refractory to sperm entry, suggesting that they are able to establish a slow block to polyspermy.

Role of animal pole protuberance and microtubules during meiosis in sea cucumber Apostichopus japonicus oocytes

NASA Astrophysics Data System (ADS)

Pang, Zhenguo; Chang, Yaqing; Sun, Huiling; Yu, Jiaping

2010-05-01

Fully grown oocytes of Apostichopus japonicus have a cytoplasmic protuberance where the oocyte attaches to the follicle. The protuberance and the oolamina located on the opposite side of the oocyte indicate the animal-vegetal axis. Two pre-meiotic centrosomes are anchored to the protuberance by microtubules between centrosomes and protuberance. After meiosis reinitiation induced by DTT solution, the germinal vesicle (GV) migrates towards the protuberance. The GV breaks down after it migrates to the oocyte membrane on the protuberance side. The protuberance then contracts back into the oocyte and the first polar body extrudes from the site of the former protuberance. The second polar body forms beneath the first. Thus the oocyte protuberance indicates the presumptive animal pole well before maturation of the oocyte.

Regulation of Fatty Acid Oxidation in Mouse Cumulus-Oocyte Complexes during Maturation and Modulation by PPAR Agonists

PubMed Central

Dunning, Kylie R.; Anastasi, Marie R.; Zhang, Voueleng J.; Russell, Darryl L.; Robker, Rebecca L.

2014-01-01

Fatty acid oxidation is an important energy source for the oocyte; however, little is known about how this metabolic pathway is regulated in cumulus-oocyte complexes. Analysis of genes involved in fatty acid oxidation showed that many are regulated by the luteinizing hormone surge during in vivo maturation, including acyl-CoA synthetases, carnitine transporters, acyl-CoA dehydrogenases and acetyl-CoA transferase, but that many are dysregulated when cumulus-oocyte complexes are matured under in vitro maturation conditions using follicle stimulating hormone and epidermal growth factor. Fatty acid oxidation, measured as production of 3H2O from [3H]palmitic acid, occurs in mouse cumulus-oocyte complexes in response to the luteinizing hormone surge but is significantly reduced in cumulus-oocyte complexes matured in vitro. Thus we sought to determine whether fatty acid oxidation in cumulus-oocyte complexes could be modulated during in vitro maturation by lipid metabolism regulators, namely peroxisome proliferator activated receptor (PPAR) agonists bezafibrate and rosiglitazone. Bezafibrate showed no effect with increasing dose, while rosiglitazone dose dependently inhibited fatty acid oxidation in cumulus-oocyte complexes during in vitro maturation. To determine the impact of rosiglitazone on oocyte developmental competence, cumulus-oocyte complexes were treated with rosiglitazone during in vitro maturation and gene expression, oocyte mitochondrial activity and embryo development following in vitro fertilization were assessed. Rosiglitazone restored Acsl1, Cpt1b and Acaa2 levels in cumulus-oocyte complexes and increased oocyte mitochondrial membrane potential yet resulted in significantly fewer embryos reaching the morula and hatching blastocyst stages. Thus fatty acid oxidation is increased in cumulus-oocyte complexes matured in vivo and deficient during in vitro maturation, a known model of poor oocyte quality. That rosiglitazone further decreased fatty acid oxidation during in vitro maturation and resulted in poor embryo development points to the developmental importance of fatty acid oxidation and the need for it to be optimized during in vitro maturation to improve this reproductive technology. PMID:24505284

REACTIVE OXYGEN SPECIES AND OOCYTE AGING: ROLE OF SUPEROXIDE, HYDROGEN PEROXIDE AND HYPOCHLOROUS ACID

PubMed Central

GOUD, ANURADHA P.; GOUD, PRAVIN T.; DIAMOND, MICHAEL P.; GONIK, BERNARD; ABU-SOUD, HUSAM M.

2009-01-01

Aging of the unfertilized oocyte inevitably occurs following ovulation, limiting its fertilizable life-span. However, the mechanisms that regulate oocyte aging are still unclear. We hypothesize that reactive oxygen species such as superoxide (O2•−), hydrogen peroxide (H2O2), and hypochlorous acid (HOCl) are likely candidates that may initiate these changes in the oocyte. In order to test this hypothesis, we investigated direct effects of O2•− [hypoxanthine/xanthine oxidase system generating 0.12 (n=42) and 0.25 μM O2•−/min (n=45)], H2O2 (20 or 100 μM, n=60) and HOCl, (1, 10 and 100 μM, n=50) on freshly ovulated or relatively old mouse oocytes, while their sibling oocytes were fixed immediately or cultured under physiological conditions (n=96). The aging process was assessed by the zona pellucida dissolution time (ZPDT), ooplasm microtubule dynamics (OMD), and cortical granule (CG) status. The ZPDT increased 2-fold in relatively old, compared to young, untreated oocytes (P<0.0001). Exposure to O2•− increased it even further (P<0.0001). Similarly, more O2•− exposed oocytes exhibited increased OMD and major CG loss, with fewer having normal OMD and intact CG compared to untreated controls. Interestingly, young oocytes resisted “aging”, when exposed to 20 μM H2O2, while the same enhanced the aging phenomena in relatively old oocytes (P<0.05). Exposure to even very low levels of HOCl induced aging phenomena in young and relatively old oocytes, and higher concentrations of HOCl compromised oocyte viability. Overall, O2•−, H2O2 and HOCl each augment oocyte “aging”, more so in relatively old oocytes, suggesting compromised antioxidant capacity in aging oocytes. PMID:18177745

Effect of follicular flushing on reproductive outcomes in patients with poor ovarian response undergoing assisted reproductive technology.

PubMed

Souza, Anna L M; Sampaio, Marcos; Noronha, Graciele B; Coster, Ludiana G R; de Oliveira, Roberta S G; Geber, Selmo

2017-10-01

The purpose of this study is to investigate the impact of follicular flushing on the number of oocytes retrieved, oocyte maturity, fertilization rate, embryo development, and pregnancy rate of poor ovarian responders (POR). Retrospective study of 524 cycles of 384 patients with POR submitted to assisted reproductive technology (ART) and who had follicular flushing during oocyte retrieval was used in the study. We included patients with <5 oocytes at oocyte retrieval (POR group) and matching the Bologna criteria. POR patients had a mean age of 38.2 ± 4.2 years. A total of 1355 follicles (mean = 3.5 ± 1.6) were aspirated and 1040 oocytes recovered, with 709 (68.2%) obtained by direct aspiration and 331 (31.8%) by follicular flushing. We found a difference between the total number of oocytes and the number of aspirated oocytes. Overall pregnancy rate was 22%. Association was observed between pregnancy rate and the number of oocytes retrieved, the number of MII oocytes, and the number of embryos transferred. The patients matching the Bologna criteria had a mean age of 38.9 ± 3.9 years. A total of 309 follicles were aspirated (mean = 3.1 ± 1.5) and 242 oocytes recovered, with 156 (64.5%) obtained by direct aspiration and 86 (35.5%) by follicular flushing. There was a significant difference between the total number of oocytes and the number of aspirated oocytes. Overall pregnancy rate was 12.1%. There was no association between the pregnancy rate and the number of oocytes retrieved, the number of MII, and the number of embryos. Follicular flushing might be a suitable alternative to increase the number of oocytes and pregnancy rates in patients with POR.

Live birth following IVF/ICSI using oocytes from donor who was conceived via IVF: a case report.

PubMed

Kavoussi, Shahryar K; Odenwald, Kate C; Summers-Colquitt, Roxanne B; Kavoussi, Parviz K; Kavoussi, K M; Shelinbarger, Caitlin L; Pool, Thomas B

2015-11-01

The purpose of the study was to report a case of live birth following donor oocyte in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) in which the oocyte donor herself was conceived via IVF. To our knowledge, such a case has not been previously reported. Retrospective chart review; this case is reported after chart review of a successful outcome. A 42 year-old woman, with diminished ovarian reserve, and her husband desired to conceive. She underwent a fresh IVF/ICSI cycle with her own oocytes, which unfortunately was not fruitful in terms of pregnancy or cryopreserved embryos. The couple was counseled regarding the option of donor oocytes, and they elected to proceed with a fresh cycle of donor oocyte IVF/ICSI. The couple selected an anonymous oocyte donor from a donor agency who was a first-time oocyte donor and, interestingly, was conceived via IVF herself. The fresh donor oocyte/IVF/ICSI cycle did not result in pregnancy; however, two supernumerary blastocysts were cryopreserved for future cycles. The recipient's subsequent frozen-thawed embryo transfer (FET) resulted in a singleton gestation and live birth. An oocyte donor who was conceived via IVF had good ovarian response to stimulation, a good number of oocytes retrieved, and the formation and cryopreservation of blastocysts which, in a subsequent FET cycle, resulted in pregnancy and live birth for a recipient couple. To our knowledge, this is the first case reported of live birth with the use of donor oocytes from an oocyte donor who herself was conceived via IVF.

Cytoplasmic movement profiles of mouse surrounding nucleolus and not-surrounding nucleolus antral oocytes during meiotic resumption.

PubMed

Bui, Thi Thu Hien; Belli, Martina; Fassina, Lorenzo; Vigone, Giulia; Merico, Valeria; Garagna, Silvia; Zuccotti, Maurizio

2017-05-01

Full-grown mouse antral oocytes are classified as surrounding nucleolus (SN) or not-surrounding nucleolus (NSN), depending on the respective presence or absence of a ring of Hoechst-positive chromatin surrounding the nucleolus. In culture, both types of oocytes resume meiosis and reach the metaphase II (MII) stage, but following insemination, NSN oocytes arrest at the two-cell stage whereas SN oocytes may develop to term. By coupling time-lapse bright-field microscopy with image analysis based on particle image velocimetry, we provide the first systematic measure of the changes to the cytoplasmic movement velocity (CMV) occurring during the germinal vesicle-to-MII (GV-to-MII) transition of these two types of oocytes. Compared to SN oocytes, NSN oocytes display a delayed GV-to-MII transition, which can be mostly explained by retarded germinal vesicle break down and first polar body extrusion. SN and NSN oocytes also exhibit significantly different CMV profiles at four main time-lapse intervals, although this difference was not predictive of SN or NSN oocyte origin because of the high variability in CMV. When CMV profile was analyzed through a trained artificial neural network, however, each single SN or NSN oocyte was blindly identified with a probability of 92.2% and 88.7%, respectively. Thus, the CMV profile recorded during meiotic resumption may be exploited as a cytological signature for the non-invasive assessment of the oocyte developmental potential, and could be informative for the analysis of the GV-to-MII transition of oocytes of other species. © 2017 Wiley Periodicals, Inc.

Obox4 critically regulates cAMP-dependent meiotic arrest and MI-MII transition in oocytes.

PubMed

Lee, Hyun-Seo; Kim, Eun-Young; Kim, Kyeoung-Hwa; Moon, Jisook; Park, Kyung-Soon; Kim, Kwang-Soo; Lee, Kyung-Ah

2010-07-01

Extra follicular oocytes spontaneously resume meiosis in vitro, but the intact germinal vesicle (GV) is retained if the oocytes are cultured in medium containing phosphodiesterase (PDE) inhibitors or cAMP analogues. On the basis of our finding that Obox4 is prominently expressed in oocytes, the present study was conducted to determine the functional role of the homeodomain-containing factor Obox4 during in vitro oocyte maturation. After microinjection of Obox4 dsRNA into the cytoplasm of GV oocytes cultured in M16 medium, oocytes were arrested at metaphase I (MI, 77.7%) and metaphase II (MII, 22.3%). Surprisingly, however, 89% of Obox4 RNAi-treated oocytes resumed meiosis and developed to MI and MII when cultured in medium containing 0.2 mM 3-isobutyl-1-methyl-xanthine (IBMX), in which untreated oocytes maintain intact GVs. Spindles were aberrant, and chromosomes were severely aggregated with decreased MPF and MAP kinase activities in arrested MI oocytes after exposure to Obox4 RNAi. Oocytes overexpressing Obox4 retained intact GVs when cultured in M16 medium. Taken together, for the first time to our knowledge, these findings indicate that Obox4 plays a key role in the cAMP-dependent signaling cascades that maintain GV arrest. Oocytes not expressing Obox4 failed to maintain intact GVs in IBMX-supplemented medium, while GVs remained intact when oocytes were kept in plain medium and overexpressing Obox4, suggesting that Obox4 plays a critical role in cAMP-dependent cascade for maintaining intact GVs.

Betaine is accumulated via transient choline dehydrogenase activation during mouse oocyte meiotic maturation.

PubMed

McClatchie, Taylor; Meredith, Megan; Ouédraogo, Mariame O; Slow, Sandy; Lever, Michael; Mann, Mellissa R W; Zeisel, Steven H; Trasler, Jacquetta M; Baltz, Jay M

2017-08-18

Betaine ( N,N,N -trimethylglycine) plays key roles in mouse eggs and preimplantation embryos first in a novel mechanism of cell volume regulation and second as a major methyl donor in blastocysts, but its origin is unknown. Here, we determined that endogenous betaine was present at low levels in germinal vesicle (GV) stage mouse oocytes before ovulation and reached high levels in the mature, ovulated egg. However, no betaine transport into oocytes was detected during meiotic maturation. Because betaine can be synthesized in mammalian cells via choline dehydrogenase (CHDH; EC 1.1.99.1), we assessed whether this enzyme was expressed and active. Chdh transcripts and CHDH protein were expressed in oocytes. No CHDH enzyme activity was detected in GV oocyte lysate, but CHDH became highly active during oocyte meiotic maturation. It was again inactive after fertilization. We then determined whether oocytes synthesized betaine and whether CHDH was required. Isolated maturing oocytes autonomously synthesized betaine in vitro in the presence of choline, whereas this failed to occur in Chdh -/- oocytes, directly demonstrating a requirement for CHDH for betaine accumulation in oocytes. Overall, betaine accumulation is a previously unsuspected physiological process during mouse oocyte meiotic maturation whose underlying mechanism is the transient activation of CHDH. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Metabolic control of oocyte development: linking maternal nutrition and reproductive outcomes

PubMed Central

Liu, Honglin; Gu, Xi; Boots, Christina; Moley, Kelle H.

2015-01-01

Obesity, diabetes, and related metabolic disorders are major health issues worldwide. As the epidemic of metabolic disorders continues, the associated medical comorbidities, including the detrimental impact on reproduction, increase as well. Emerging evidence suggests that the effects of maternal nutrition on reproductive outcomes are likely to be mediated, at least in part, by oocyte metabolism. Well-balanced and timed energy metabolism is critical for optimal development of oocytes. To date, much of our understanding of oocyte metabolism comes from the effects of extrinsic nutrients on oocyte maturation. In contrast, intrinsic regulation of oocyte development by metabolic enzymes, intracellular mediators, and transport systems is less characterized. Specifically, decreased acid transport proteins levels, increased glucose/lipid content and elevated reactive oxygen species in oocytes have been implicated in meiotic defects, organelle dysfunction and epigenetic alteration. Therefore, metabolic disturbances in oocytes may contribute to the diminished reproductive potential experienced by women with metabolic disorders. In-depth research is needed to further explore the underlying mechanisms. This review also discusses several approaches for metabolic analysis. Metabolomic profiling of oocytes, the surrounding granulosa cells, and follicular fluid will uncover the metabolic networks regulating oocyte development, potentially leading to the identification of oocyte quality markers and prevention of reproductive disease and poor outcomes in offspring. PMID:25280482

Sex aneuploidy of unfertilized human oocytes after intracytoplasmic sperm injection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, G.; Ward, D.C.; Jones, E.E.

1994-09-01

Intracytoplasmic sperm injection (ICSI) has recently achieved successful fertilization and pregnancy in human in vitro fertilization, particularly in cases of severe male factor infertility. One criticism of this novel clinical technique is that it bypasses the natural selection process of fertilization. We use fluorescence in situ hybridization (FISH) to analyze oocytes which fail to fertilize after ICSI in the Yale IVF Program. The purpose of this study is to determine whether failed fertilization after ICSI can be attributed to sex chromosome aneuploidy in the oocyte. Fertilization of oocytes is determined by the presence of two pronuclei on light microscopic examinationmore » (400X). Multi-probe FISH with DAPI (4,6,-diamino-2-phenyl-indole) counterstain is then performed to determine oocyte ploidy and the presence of decondensed sperm. Centromeric probes for X, Y and 17 are used simultaneously in each oocyte for in situ hybridization to oocyte chromatin. In all oocytes examined after ICSI to date, unfertilized oocytes have decondensed sperm DNA present confirming appropriate intracytoplasmic placement of the sperm. Preliminary results obtained from 31 oocytes have not identified any sex chromosome aneuploidies. The FISH technique used in post-ICSI oocytes is a model system for delineating genetic causes of failed fertilization in the human.« less

Fatty Acid β-Oxidation Is Essential in Leptin-Mediated Oocytes Maturation of Yellow Catfish Pelteobagrus fulvidraco.

PubMed

Song, Yu-Feng; Tan, Xiao-Ying; Pan, Ya-Xiong; Zhang, Li-Han; Chen, Qi-Liang

2018-05-14

Although several studies have been conducted to study leptin function, information is very scarce on the molecular mechanism of leptin in fatty acid β-oxidation and oocytes maturation in fish. In this study, we investigated the potential role of fatty acid β-oxidation in leptin-mediated oocytes maturation in Pelteobagrus fulvidraco . Exp. 1 investigated the transcriptomic profiles of ovary and the differential expression of genes involved in β-oxidation and oocytes maturation following rt-hLEP injection; rt-hLEP injection was associated with significant changes in the expression of genes, including twenty-five up-regulated genes ( CPT1 , Acsl , Acadl , Acadm , Hadhb , Echsl , Hsd17b4 , Acca , PPARα , CYP8B1 , ACOX1 , ACBP , MAPK , RINGO , Cdc2 , MEK1 , IGF-1R , APC/C, Cdk2 , GnRHR, STAG3 , SMC1 , FSHβ and C-Myc ) and ten down-regulated gene ( PPARγ , FATCD36 , UBC , PDK1 , Acads , Raf , Fizzy , C3H-4 , Raf and PKC ), involved in fatty acid β-oxidation and oocytes maturation. In Exp. 2, rt-hLEP and specific inhibitors AG490 (JAK-STAT inhibitor) were used to explore whether leptin induced oocytes maturation, and found that leptin incubation increased the diameters of oocytes and percentage of germinal vesicle breakdown (GVBD)-MII oocytes, up-regulated mRNA levels of genes involved in oocytes maturation and that leptin-induced oocyte maturation was related to activation of JAK-STAT pathway. In Exp. 3, primary oocytes of P. fulvidraco were treated with (R)-(+)-etomoxir (an inhibitor of β-oxidation) or l-carnitine (an enhancer of β-oxidation) for 48 h under rt-hLEP incubation. Exp. 3 indicated that the inhibition of fatty acid β-oxidation resulted in the down-regulation of gene expression involved in oocytes maturation, and repressed the leptin-induced up-regulation of these gene expression. Activation of fatty acid β-oxidation improved the maturation rate and mean diameter of oocytes, and up-regulated gene expression involved in oocytes maturation. Leptin is one of the main factors that links fatty acid β-oxidation with oocyte maturation; β-oxidation is essential for leptin-mediated oocyte maturation in fish.

Insufficient amount of Cdc2 and continuous activation of Wee1 B are the cause of meiotic failure in porcine growing oocytes.

PubMed

Nishimura, Takanori; Shimaoka, Takuma; Kano, Kiyoshi; Naito, Kunihiko

2009-10-01

In mammals, growing oocytes with a diameter less than 80% of that of full-grown oocytes cannot start meiotic maturation, and their maturation promoting factor (MPF) cannot be activated by hormonal stimulation or isolation from follicles. The aim of the present study was to identify the key molecules responsible for meiotic failure of these growing oocytes (referred to as "small oocytes" in the present study). To this end, we altered the expression of the molecules involved in MPF activation in the small oocytes of pigs by injecting them with mRNA or antisense RNA (asRNA) and examined the effects on the meiotic ability of the small oocytes. Immunoblotting analyses revealed three defects in small oocytes compared with full-grown oocytes, an inactive mitogen activated protein kinase (MAPK) cascade, a failure of cyclin B synthesis and an insufficient amount of Cdc2. Injection with mRNAs of Mos, the uppermost molecule of the MAPK cascade, cyclin B1, cyclin B2 or Cdc2 into small porcine oocytes indicated directly and for the first time that the cause of meiotic failure of porcine small oocytes is an insufficient amount of Cdc2 rather than MAPK inactivation or failure of cyclin B synthesis. Next, in order to suppress Myt1 and Wee1B, which phosphorylates at inhibitory phosphorylation sites of Cdc2 and inactive MPF, we injected their asRNAs into the porcine small oocytes and found that the Wee1B asRNA significantly increased meiotic ability, whereas the Myt1 asRNA had no effect. When Cdc2 overexpression and suppression of Wee1B expression were simultaneously induced in the small oocytes of pigs, about 70% of the small oocytes resumed meiosis, and this rate was nearly comparable with that of the full-grown oocytes. These results strongly suggest that an insufficient amount of Cdc2 and continuous activation of Wee1 B are the cause of meiotic failure of small oocytes in pigs.

Amino acid turnover by human oocytes is influenced by gamete developmental competence, patient characteristics and gonadotrophin treatment

PubMed Central

Hemmings, K.E.; Maruthini, D.; Vyjayanthi, S.; Hogg, J.E.; Balen, A.H.; Campbell, B.K.; Leese, H.J.; Picton, H.M.

2013-01-01

STUDY QUESTION Can amino acid profiling differentiate between human oocytes with differing competence to mature to metaphase II (MII) in vitro? SUMMARY ANSWER Oocytes which remained arrested at the germinal vesicle (GV) stage after 24 h of in vitro maturation (IVM) displayed differences in the depletion/appearance of amino acids compared with oocytes which progressed to MII and patient age, infertile diagnosis and ovarian stimulation regime significantly affected oocyte amino acid turnover during IVM. WHAT IS KNOWN ALREADY Amino acid profiling has been proposed as a technique which can distinguish between human pronucleate zygotes and cleavage stage embryos with the potential to develop to the blastocyst stage and implant to produce a pregnancy and those that arrest. Most recently, the amino acid turnover by individual bovine oocytes has been shown to be predictive of oocyte developmental competence as indicated by the gamete's capacity to undergo fertilization and early cleavage divisions in vitro. STUDY DESIGN, SIZE, DURATION The study was conducted between March 2005 and March 2010. A total of 216 oocytes which were at the GV or metaphase I (MI) stages at the time of ICSI were donated by 67 patients. PARTICIPANTS/MATERIALS, SETTINGS, METHODS The research was conducted in university research laboratories affiliated to a hospital-based infertility clinic. Oocytes were cultured for 24 h and the depletion/appearance of amino acids was measured during the final 6 h of IVM. Amino acid turnover was analysed in relation to oocyte meiotic progression, patient age, disease aetiology and controlled ovarian stimulation regime. MAIN RESULTS AND THE ROLE OF CHANCE The depletion/appearance of key amino acids was linked to the maturation potential of human oocytes in vitro. Oocytes which arrested at the GV stage (n = 9) depleted significantly more valine and isoleucine than those which progressed to MI (n = 32) or MII (n = 107) (P < 0.05). Glutamate, glutamine, arginine and valine depletion or appearance differed in MII versus degenerating oocytes (n = 20) (P < 0.05). Glutamine, arginine, methionine, phenylalanine, total depletion and total turnover all differed in oocytes from patients aged < 35 years versus patients ≥35 years (P < 0.05). MII oocytes obtained following ovarian stimulation with recombinant FSH depleted more isoleucine (P < 0.05) and more alanine and lysine (P < 0.05) appeared than oocytes from hMG-stimulated cycles. MII oocytes from patients with a polycystic ovary (PCO) morphology (n = 33) depleted more serine (P < 0.05) than oocytes from women with normal ovaries (n = 61). LIMITATIONS, REASONS FOR CAUTION Immature oocytes collected at the time of ICSI were used as the model for human oocyte maturation. These oocytes have therefore failed to respond to the ovulatory hCG trigger in vivo (they are meiotically incompetent), and have limited capacity to support embryo development in vitro. The lack of cumulus cells and stress of the conditions in vitro may have influenced turnover of amino acids, and owing to the small sample sizes further studies are required to confirm these findings. WIDER IMPLICATIONS OF THE FINDINGS The findings provide support for the hypothesis that oocyte metabolism reflects oocyte quality. Longitudinal studies are required to link these functional metabolic indices of human oocyte quality with embryo developmental competence. Oocyte amino acid profiling may be a useful tool to quantify the impact of new assisted reproduction technologies (ART) on oocyte quality. STUDY FUNDING/COMPETING INTERESTS This project was funded by the UK Biology and Biotechnology Research Council (BB/C007395/1) and the Medical Research Council (G 0800250). K.E.H was in receipt of a British Fertility Society/Merck Serono studentship. H.J.L. is a shareholder in Novocellus Ltd, a company which seeks to devise a non-invasive biochemical test of embryo health. PMID:23335609

HIGH INCIDENCE OF POLYSPERMIC FERTILIZATION IN BOVINE OOCYTES MATURED IN VITRO AFTER CRYOTOP VITRIFICATION.

PubMed

Hwang, In-Sul; Kwon, Dae-Jin; Im, Gi-Sun; Tashima, Kazuya; Hochi, Shinichi; Hwang, Seongsoo

2016-01-01

Vitrification with the Cryotop device is the most promising technique for oocyte cryopreservation, but the high post-warming morphological survival of bovine oocytes does not guarantee high developmental competence after in vitro fertilization (IVF). This study was designed to examine achievement of normal fertilization in bovine oocytes vitrified-warmed with the Cryotop device. Oocytes were matured in vitro and vitrified-warmed after complete removal of the cumulus layers. Distribution of cortical granules (CGs) was assessed by Lens culinaris agglutinin (LCA) lectin staining. Ten hours after IVF, presumptive zygotes were analyzed for pronuclear formation. Day-8 blastocysts were harvested and stained with Hoechst-33342 for total cell counting. Both yield and mean cell number of the blastocysts were impaired by Cryotop vitrification. Incidence of polyspermic fertilization was three-times higher in vitrified oocytes compared to fresh oocytes. No difference in CG distribution was found between vitrified and fresh oocytes. Polyspermic fertilization induced in vitrified-warmed bovine oocytes may be one of the possible causes responsible for their low developmental potential.

Expression of mammalian beta-adrenergic receptors in Xenopus laevis oocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bahouth, S.W.; Malbon, C.C.

1987-05-01

Xenopus laevis oocytes are a useful transcription and expression system for DNA and RNA, respectively. Total cellular RNA was extracted from mouse lymphoma S49 cells and poly(A)/sup +/mRNA prepared by affinity chromatography of RNA on oligo(dT) cellulose. The membranes of S49 cells contain beta-adrenergic receptors that display pharmacological characteristics of beta/sub 2/-subtype. Xenopus laevis oocytes were injected with 50 ng of mRNA/oocyte. Expression of beta-adrenergic receptors in oocytes incubated for 30 hr after microinjection was assessed in membranes by radioligand binding using (/sup 3/H) dihydroalprenolol. The injected oocytes displayed 0.34 fmol receptor/oocyte as compared to 0.02 fmol receptor/oocyte in themore » control oocytes. The affinity of beta-adrenergic receptors in injected oocytes for this radioligand was 2 nM, a value similar to the affinity of beta-adrenergic receptors for DHA in S49 cell membranes. The potency of beta-adrenergic agonists in competing for DHA binding to oocytes membranes was isoproterenol > epinephrine > norepineprine, indicating that the expressed beta-adrenergic receptors were of the beta/sub 2/-subtype. The K/sub I/ of these agonists for the beta-adrenergic receptor in oocyte membranes was 0.03, 0.15 and 1.2 ..mu..M, respectively. The role of post-translational modification in dictating receptor subtype is analyzed using mRNA of beta/sub 1/- as well as beta/sub 2/-adrenergic receptors.« less

Optimum culture duration for growing oocytes to attain meiotic and fertilization competence.

PubMed

Yamochi, Takayuki; Hashimoto, Shu; Yamanaka, Masaya; Nakaoka, Yoshiharu; Morimoto, Yoshiharu

2017-12-15

To determine the optimum culture duration for porcine growing oocytes (GOs) to attain maturation competence, we examined the meiotic competence, chromatin configuration, and fertilization ability of porcine oocytes obtained from early antral follicles and cultured for 10-16 days. The survival rate of oocytes after 10 days of culture (62.8%) was similar to that of oocytes after 12 days of culture (55%) and significantly higher than that of oocytes cultured for 14 and 16 days (52.9 and 24.3%, respectively). No significant difference was observed in the diameter of ooplasm from oocytes cultured for different durations (117.4-118.3 μm). The maturation rates of surviving oocytes after 10 and 16 days of culture (38.3 and 22.7%, respectively) were significantly lower than those of oocytes cultured for 12 and 14 days, and their in vivo counterparts (52.8-62.4%). The number of oocytes with surrounded-nucleolus chromatin was significantly lower in the 10-day culture group (78.4%) as compared with 14-day culture and in vivo counterpart groups (93.6 and 95.1%, respectively). After in vitro maturation and intracytoplasmic sperm injection, no significant difference was observed in the rate of fertilization among oocytes cultured for 12 and 14 days, and their in vivo counterparts (40.5-47.2%). Thus, porcine GOs required at least 12 days to acquire meiotic and fertilization competence, and the culture duration to maximize the number of mature oocytes ranged from 12 to 14 days.

Association between oocyte number retrieved with live birth rate and birth weight: an analysis of 231,815 cycles of in vitro fertilization

PubMed Central

Baker, Valerie L.; Brown, Morton B.; Luke, Barbara; Conrad, Kirk P.

2015-01-01

Objective To determine if number of oocytes correlates with live birth rate and incidence of low birthweight (LBW). Design Retrospective cohort. Setting N/A. Patients Women undergoing fresh embryo transfer utilizing either autologous (n=194,627) or donor (n=37,188) oocytes whose cycles were reported to the Society for Assisted Reproductive Technology 2004–2010. Main outcome measures Live birth rate, birthweight, birth weight z-score, LBW. Interventions None. Results For both autologous and donor oocyte cycles, increasing number of oocytes retrieved paralleled live birth rate and embryos available for cryopreservation in most analyses performed with all models adjusted for age and prior births. For cycles achieving singleton pregnancy using autologous oocytes via transfer of 2 embryos, a higher number of oocytes retrieved was associated with lower mean birth weight, lower birthweight z-score, and greater incidence of LBW. In contrast, for cycles using donor oocytes, there was no association of oocyte number retrieved with measures of birthweight. Conclusions A higher number of oocytes retrieved was associated with an increased incidence of LBW in autologous singleton pregnancies resulting from transfer of 2 embryos but not in donor oocyte cycles. Although the effect of high oocyte number on the incidence of LBW in autologous cycles was of modest magnitude, further study is warranted to determine if a subgroup of women may be particularly vulnerable. PMID:25638421

Mitochondrial distribution and activity in human mature oocytes: gonadotropin-releasing hormone agonist versus antagonist for pituitary down-regulation.

PubMed

Dell'Aquila, Maria Elena; Ambruosi, Barbara; De Santis, Teresa; Cho, Yoon Sung

2009-01-01

To analyze the effects of GnRH agonists versus antagonists on mitochondrial distribution and activity in human mature oocytes. Randomized research experimental study. Academic basic research laboratory and hospital-based fertility center. Two hundred twenty-five supernumerary mature oocytes from 44 patients. Fluorescent staining and confocal laser scanning microscopy on oocytes after the use of either GnRH agonist (group A) or GnRH antagonist (group B). Oocyte mitochondrial distribution pattern and activity using MitoTracker Orange CMTM Ros. More oocytes showing polarized mitochondrial distribution pattern were found in group A than in group B (35% vs. 14%). In group B, hCG rather than GnRH agonist, for ovulation induction, resulted in more oocytes showing heterogeneous (57% vs. 14%), in particular polarized (24% vs. 0) mitochondrial distribution. In groups A and B, fluorescence intensity did not vary according to mitochondrial distribution pattern. However, fluorescence intensity was higher in oocytes with polarized and large granules configurations in group B compared to group A. The GnRH agonist and antagonist may have different effects on oocyte mitochondrial distribution pattern and activity. The GnRH antagonist may induce mitochondrial hyperactivity, which may be detrimental to the oocyte.

Patterns of oocyte development in natural habitat and captive Salminus hilarii Valenciennes, 1850 (Teleostei: Characidae).

PubMed

Honji, R M; Narcizo, A M; Borella, M I; Romagosa, E; Moreira, R G

2009-03-01

Fecundity and oocyte development in Salminus hilarii female brood stock were analyzed with the aim of investigating the impact of migration impediment on oogenesis. Histological analyses of the ovaries were performed in adult females caught in two different environments--the Tietê River (natural) and captivity--and the gonadossomatic index, oocyte diameter and fecundity determined. Five germ cell development stages (oogonium, perinucleolar, cortical alveoli, vitellogenic, ripe) and two other structures (postovulatory follicles and atretic oocytes) were observed in females caught in the river. Captive animals lacked the ripe oocytes and postovulatory follicles and had a relatively higher number of atretic oocytes. Females in captivity are known to produce larger oocytes, and they release fewer eggs in each spawn (absolute fecundity) when compared with animals that are able to migrate. Our results suggest that the Tietê River is undergoing alterations which are being reflected in the reproductive performance of S. hilarii, mainly due to the presence of atretic oocytes in females caught in the river. The lack of postovulatory follicles and ripe oocytes in captive animals reveals that migratory impediment negatively impacts final oocyte maturation. However, the stage of maturation reached is adequate for ovulation induction with hormone manipulation.

Merotelic kinetochore attachment in oocyte meiosis II causes sister chromatids segregation errors in aged mice.

PubMed

Cheng, Jin-Mei; Li, Jian; Tang, Ji-Xin; Hao, Xiao-Xia; Wang, Zhi-Peng; Sun, Tie-Cheng; Wang, Xiu-Xia; Zhang, Yan; Chen, Su-Ren; Liu, Yi-Xun

2017-08-03

Mammalian oocyte chromosomes undergo 2 meiotic divisions to generate haploid gametes. The frequency of chromosome segregation errors during meiosis I increase with age. However, little attention has been paid to the question of how aging affects sister chromatid segregation during oocyte meiosis II. More importantly, how aneuploid metaphase II (MII) oocytes from aged mice evade the spindle assembly checkpoint (SAC) mechanism to complete later meiosis II to form aneuploid embryos remains unknown. Here, we report that MII oocytes from naturally aged mice exhibited substantial errors in chromosome arrangement and configuration compared with young MII oocytes. Interestingly, these errors in aged oocytes had no impact on anaphase II onset and completion as well as 2-cell formation after parthenogenetic activation. Further study found that merotelic kinetochore attachment occurred more frequently and could stabilize the kinetochore-microtubule interaction to ensure SAC inactivation and anaphase II onset in aged MII oocytes. This orientation could persist largely during anaphase II in aged oocytes, leading to severe chromosome lagging and trailing as well as delay of anaphase II completion. Therefore, merotelic kinetochore attachment in oocyte meiosis II exacerbates age-related genetic instability and is a key source of age-dependent embryo aneuploidy and dysplasia.

Expression of functional neurotransmitter receptors in Xenopus oocytes after injection of human brain membranes

NASA Astrophysics Data System (ADS)

Miledi, Ricardo; Eusebi, Fabrizio; Martínez-Torres, Ataúlfo; Palma, Eleonora; Trettel, Flavia

2002-10-01

The Xenopus oocyte is a very powerful tool for studies of the structure and function of membrane proteins, e.g., messenger RNA extracted from the brain and injected into oocytes leads to the synthesis and membrane incorporation of many types of functional receptors and ion channels, and membrane vesicles from Torpedo electroplaques injected into oocytes fuse with the oocyte membrane and cause the appearance of functional Torpedo acetylcholine receptors and Cl channels. This approach was developed further to transplant already assembled neurotransmitter receptors from human brain cells to the plasma membrane of Xenopus oocytes. Membranes isolated from the temporal neocortex of a patient, operated for intractable epilepsy, were injected into oocytes and, within a few hours, the oocyte membrane acquired functional neurotransmitter receptors to -aminobutyric acid, -amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, kainate, and glycine. These receptors were also expressed in the plasma membrane of oocytes injected with mRNA extracted from the temporal neocortex of the same patient. All of this makes the Xenopus oocyte a more useful model than it already is for studies of the structure and function of many human membrane proteins and opens the way to novel pathophysiological investigations of some human brain disorders.

Influence of Meiotic Stages on Developmental Competence of Goat’ Oocyte After Vitrification

NASA Astrophysics Data System (ADS)

Wahyuningsih, S.; Ihsan, M. N.

2018-02-01

This objective of this research was to investigate effect of goat oocyte meiotic stages on developmental competence after cryopreservation. Ovaries were collected from slaugterhouse and oocytes was aspirated from2-6 mm of follicles. Oocyte with compacted cumulus cells and evenly granulated ooplasm were selected for this experiment. The lenght of in vitro maturation before vitrification was 8 or 22 h in IVM media TCM 199 + FCS 10 % + PMSG 10 IU + hCG 10 IU at 38.5 °C in a humidified atmosphere of 5 % CO2 in air and were vitrified. After vitrification process, GVBD and MII oocyte were matured for 18 or 4 h to fullfill 26 h maturation requirement and then oocytes were subjected to IVF and culture. Cleavage and blastocyst formation rate were to asses their developmental competence. Cleavage rates were obtained for both GVBD ( 56.78 %) and MII (69.64 % ) oocytes (P<0.05). Proportion of cleaved embryos from vitrified MII oocytes develop into blastocysts higher (P<0.05) than those from vitrified GVBD oocytes (10.25% vs 3.54%) repectively. Goat oocytes in different maturation stages response to vitrification differently and MII stages have better developmental competence than GVBD.

Relationship between time post-ovulation and progesterone on oocyte maturation and pregnancy in canine cloning.

PubMed

Kim, Joung Joo; Park, Kang Bae; Choi, Eun Ji; Hyun, Sang Hwan; Kim, Nam-Hyung; Jeong, Yeon Woo; Hwang, Woo Suk

2017-10-01

Canine oocytes ovulated at prophase complete meiosis and continue to develop in presence of a high progesterone concentration in the oviduct. Considering that meiotic competence of canine oocyte is accomplished in the oviductal environment, we postulate that hormonal milieu resulting from the circulating progesterone concentration may affect oocyte maturation and early development of embryos. From 237 oocyte donors, 2620 oocytes were collected and their meiotic status and morphology were determined. To determine optimal characteristics of the mature oocytes subjected to nuclear transfer, a proportion of the meiotic status of the oocytes were classified in reference to time post-ovulation as well as progesterone (P4) level. A high proportion of matured oocytes were collected from >126h (55.5%) post-ovulation or 40-50ngmL -1 (46.4%) group compared to the other groups. Of the oocyte donors that provided mature oocytes in vivo, there was no correlation between serum progesterone of donors and time post ovulation, however, time post-ovulation were significantly shorter for <30ng/mL group (P<0.05). Using mature oocytes, 1161 cloned embryos were reconstructed and transferred into 77 surrogates. In order to determine the relationship between pregnancy performance and serum progesterone level, embryos were transferred into surrogates showing various P4 serum levels. The highest pregnancy (31.8%) and live birth cloning efficacy (2.2%) rates were observed when the embryos were transferred into surrogates with circulating P4 levels were from 40 to 50ngmL -1 . In conclusion, measurement of circulating progesterone of female dog could be a suitable an indicator of the optimal time to collect quality oocyte and to select surrogates for cloning. Copyright © 2017 Elsevier B.V. All rights reserved.

Ultrastructural markers of quality are impaired in human metaphase II aged oocytes: a comparison between reproductive and in vitro aging.

PubMed

Bianchi, S; Macchiarelli, G; Micara, G; Linari, A; Boninsegna, C; Aragona, C; Rossi, G; Cecconi, S; Nottola, S A

2015-09-01

Childbearing delay contributes to the increase of subfertile couples that require assisted reproductive technology (ART). Subfertility relates with reproductive aging (RA). In vitro aging (IvA) (due to extended culture) may also impair oocyte competence. Aims of this study were to evaluate and compare the oocyte ultrastructure after RA and IvA. Cumulus-oocyte complexes (COCs) (n = 68), with metaphase II oocyte and expanded cumulus, from consenting patients (<35 years old and ≥35 years old, n = 36), were selected by phase contrast microscopy and fixed at pick up, or after 24 h culture. COCs (n = 44) were studied by light and qualitative/morphometric transmission electron microscopy. Two-way ANOVA, with age and culture as grouping factors, was applied for statistical analysis (p < 0.05). Metaphase II cumulus-free oocytes (n = 24) were selected for confocal microscopy observations. Significant decrease of mitochondria-smooth endoplasmic reticulum aggregates, increase of mitochondria-vesicle complexes size and amount, decrease of cortical granules and microvilli, and alterations of the spindle structure characterized both RA and IvA oocytes. These changes were significantly more evident in the RA oocytes submitted to IvA. RA oocytes also showed changes of the zona pellucida and occurrence of vacuoles after culture. Cumuli appeared re-compacted after culture, irrespective of the age of the patients. These data demonstrated that aging is related to decay of oocyte ultrastructural quality, and that oocytes from elder women are more sensitive to prolonged culture (IvA) than the oocytes from younger women. These morphological results should be considered when applying ART in aged patients, rescue ICSI, or artificial oocyte activation.

The influence of N-acetyl-L-cysteine on damage of porcine oocyte exposed to zearalenone in vitro

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lai, Fang-Nong; Institute of Reproductive Sciences, Qingdao Agricultural University, Qingdao 266109; Ma, Jun-Yu

Zearalenone (ZEA), one of the mycotoxins produced by Fusarium fungi, impacts porcine reproduction by interfering with the estrogen signaling pathway. Previous studies have shown that ZEA inhibits porcine oocyte maturation through the formation of aberrant spindle. To explore the effect of ZEA on porcine oocyte meiotic maturation, the extent of both nuclear and cytoplasmic maturation was examined in this study. Compared with control group, presence of ZEA (3 μM) during oocyte maturation, significantly inhibited the polar body extrusions from 71% to 51%, and significantly increased intracellular reactive oxygen species (ROS) level (12.01 vs. 5.89). Intracellular glutathione (GSH) content in ZEAmore » treatment group was lower than in the control group (1.08 pmol/oocyte vs. 0.18 pmol/oocyte), and cortical granules of cortical area distributed oocytes were reduced (88% vs. 62%). ZEA decreases cumulus expansion in both morphology and mRNA level (HAS2, PTX3, TNFAIP6 and CX43). Addition of N-acetyl-L-cysteine (NAC) to the oocyte maturation media reversed the ZEA-induced inhibition of polar body extrusion (from 69% to 81%), up-regulated ROS (from 7.9 to 6.5), down-regulated GSH content (from 0.16 to 0.82 pmol/oocyte) and recovered cumulus cells expansion in morphology and mRNA level. It is concluded that ZEA affects both oocyte nucleus and cytoplasmic maturation during in vitro maturation, and NAC can reverse these damages to some extent. - Highlights: • ZEA significantly inhibited the polar body extrusions during oocyte maturation. • ZEA significantly increased intracellular ROS level and reduced GSH content. • ZEA disturbed cortical granules of cortical area distributed oocytes. • NAC reversed the ZEA-induced inhibition of oocyte maturation.« less

Parthenogenic Blastocysts Derived from Cumulus-Free In Vitro Matured Human Oocytes

PubMed Central

McElroy, Sohyun L.; Byrne, James A.; Chavez, Shawn L.; Behr, Barry; Hsueh, Aaron J.; Westphal, Lynn M.; Reijo Pera, Renee A.

2010-01-01

Background Approximately 20% of oocytes are classified as immature and discarded following intracytoplasmic sperm injection (ICSI) procedures. These oocytes are obtained from gonadotropin-stimulated patients, and are routinely removed from the cumulus cells which normally would mature the oocytes. Given the ready access to these human oocytes, they represent a potential resource for both clinical and basic science application. However culture conditions for the maturation of cumulus-free oocytes have not been optimized. We aimed to improve maturation conditions for cumulus-free oocytes via culture with ovarian paracrine/autocrine factors identified by single cell analysis. Methodology/Principal Finding Immature human oocytes were matured in vitro via supplementation with ovarian paracrine/autocrine factors that were selected based on expression of ligands in the cumulus cells and their corresponding receptors in oocytes. Matured oocytes were artificially activated to assess developmental competence. Gene expression profiles of parthenotes were compared to IVF/ICSI embryos at morula and blastocyst stages. Following incubation in medium supplemented with ovarian factors (BDNF, IGF-I, estradiol, GDNF, FGF2 and leptin), a greater percentage of oocytes demonstrated nuclear maturation and subsequently, underwent parthenogenesis relative to control. Similarly, cytoplasmic maturation was also improved as indicated by development to blastocyst stage. Parthenogenic blastocysts exhibited mRNA expression profiles similar to those of blastocysts obtained after IVF/ICSI with the exception for MKLP2 and PEG1. Conclusions/Significance Human cumulus-free oocytes from hormone-stimulated cycles are capable of developing to blastocysts when cultured with ovarian factor supplementation. Our improved IVM culture conditions may be used for obtaining mature oocytes for clinical purposes and/or for derivation of embryonic stem cells following parthenogenesis or nuclear transfer. PMID:20539753

Effect of Long-Term Exposure of Donor Nuclei to the Oocyte Cytoplasm on Production of Cloned Mice Using Serial Nuclear Transfer.

PubMed

Wakayama, Sayaka; Tanabe, Yoshiaki; Nagatomo, Hiroaki; Mizutani, Eiji; Kishigami, Satoshi; Wakayama, Teruhiko

2016-11-01

Although animal cloning is becoming increasingly practicable, cloned embryos possess many abnormalities and so there has been a low success rate for producing live animals. This is most likely due to incomplete reprogramming of somatic cell nuclei before they start to develop as the donor nuclei are usually only exposed to the oocyte cytoplasm for 1-2 hours before reconstructed oocytes are activated to avoid oocyte aging. Therefore, in this study, we attempted to extend the exposure period of somatic cell nuclei to the oocyte cytoplasm to determine whether this could enhance reprogramming of donor nuclei. Donor nuclei were transferred into oocytes, following which pseudo-MII spindles (pMIIs) derived from these were extracted and injected into newly collected enucleated oocytes 24 hours after the first nuclear transfer (NT). These serial NT oocytes were then activated and their developmental potential was examined to full term. There was no obvious difference in the pMIIs of reconstructed oocytes at 6 and 24 hours after donor nucleus injection; however, in both of these, the chromosomes were more widely spread inside the spindle than in fresh intact oocytes. Furthermore, a few chromosomes remained in 25% and 47% of these enucleated oocytes at 6 and 24 hours after donor nucleus injection, respectively. When these pMIIs were injected into fresh enucleated oocytes, the developmental rate to blastocyst was significantly lower, but we could still obtain several healthy cloned offspring. Thus, serial NT at intervals of 24 hours using fresh oocytes is possible, but the success rate could not be improved due to loss of chromosomes during the second NT.

[Intracellular free calcium changes of mouse oocytes during activation induced by ethanol or electrical stimulations and parthenogenetic development].

PubMed

Deng, M Q; Fan, B Q

1994-09-01

Oocytes collected 18-19 h after HCG injection were stimulated with 7-8% ethanol or electrical pulses (1.7 KV/cm field strength, 80-100 microseconds duration, 3-4 times, 5-6 min interval). The parthenogenetic embryos derived from the above-mentioned methods developed to blastocyst stage just like those developed from fertilized eggs. Mouse oocytes were rather sensitive to ethanol stimulation. More than 95% of the treated oocytes were activated after stimulation of 7-8% ethanol for 5 min. Multiple electrical stimulations induced higher activation percentages of oocytes than only single electrical stimulation (71.5% vs. 63.6%). Intact oocytes were loaded with fluorescent Ca2+ indicator fura-2 and intracellular free calcium changes during artificial activation were measured by fluorescence detector. The results showed that ethanol could induce repetitive transient Ca2+ concentration increase in activated oocytes. Single electrical stimulation only induced single free calcium concentration elevation in oocyte while multiple electrical pulses could induce repetitive Ca2+ increase (each electrical pulse elicited the corresponding Ca2+ concentration peak). The pronuclei were not observed in the oocytes which had not exhibited calcium concentration rise during activation. Apart from electrical stimulation parameter, sufficient amount of Ca2+ in electric medium was crucial to mouse oocyte activation when stimulated with electrical pulses. The oocytes were hardly activated by electrical stimulations in a medium without Ca2+ even with longer pulse duration and the intracellular free calcium concentration in the oocytes showed no elevation. This indicates that the inflow of extracellular Ca2+ from tiny pores across the oocyte membrane caused by electrical stimulation is the main source of intracellular free calcium increase.(ABSTRACT TRUNCATED AT 250 WORDS)

Pronuclear synchronization and nuclear morphology of mature and in vitro matured oocytes in the rat: an ultrastructural study.

PubMed

Cincik, M; Baykal, B; Zeteroglu, S; Onalan, G; Ceyhan, S T; Ergur, R

2005-01-01

The objective of this study was to evaluate synchronous and asynchronous pronucleus (PN) formation and the related patterns of juxtapositional nucleolus (n) formation in immature (prophase I [PI] and metaphase I [MI]) and mature (metaphase II [MII]) oocytes after fertilization, both ultrastructurally and at the level of light microscope. A single dose of 15 IU gonadotrophin was injected subcutaneously to twenty four 26-wk-old, female Wistar rats to induce ovulation. Human chorionic gonadotrophin (4 IU) was administered 40 h later, and after 4-6 h the ovaries were dissected, and the oocytes were aspirated. A total of 214 rat oocytes were classified according to a maturation index as follows: group I, 80 PI oocytes; group II, 50 MI oocytes; and group III, 84 MII oocytes. Immature oocytes were in vitro matured for 18-36 h. Spermatozoa were acquired by microepididymal sperm aspiration and processed using swim-up technique. Intracytoplasmic sperm injection was performed on mature oocytes after 2 h of incubation and on in vitro matured (IVM) oocytes 4 h after maturation. Pronuclear synchronization [both pronucleases (PNs) centrally located, equal sized, with equal numbers and sizes of juxtapositional nucleoli (Nn)] was observed in fertilized oocytes. Asynchronous PN formation (diversity between male and female PNs, related to dimensions, localization, and the number of Nn) in groups I, II, and III was found in 75, 86, and 47% of preembryos, respectively. There was a significant difference of synchronous pronuclear formation between mature and IVM oocytes (P < 0.05). In IVM oocytes, asynchronous PN formation is high, and juxtapositional pronucleolar patterns are observed to be low by transmission electron microscope (TEM).

Molecular and cellular mechanisms of sperm-oocyte interactions opinions relative to in vitro fertilization (IVF).

PubMed

Anifandis, George; Messini, Christina; Dafopoulos, Konstantinos; Sotiriou, Sotiris; Messinis, Ioannis

2014-07-22

One of the biggest prerequisites for pregnancy is the fertilization step, where a human haploid spermatozoon interacts and penetrates one haploid oocyte in order to produce the diploid zygote. Although fertilization is defined by the presence of two pronuclei and the extraction of the second polar body the process itself requires preparation of both gametes for fertilization to take place at a specific time. These preparations include a number of consecutive biochemical and molecular events with the help of specific molecules and with the consequential interaction between the two gametes. These events take place at three different levels and in a precise order, where the moving spermatozoon penetrates (a) the outer vestments of the oocyte, known as the cumulus cell layer; (b) the zona pellucida (ZP); where exocytosis of the acrosome contents take place and (c) direct interaction of the spermatozoon with the plasma membrane of the oocyte, which involves a firm adhesion of the head of the spermatozoon with the oocyte plasma membrane that culminates with the fusion of both sperm and oocyte membranes (Part I). After the above interactions, a cascade of molecular signal transductions is initiated which results in oocyte activation. Soon after the entry of the first spermatozoon into the oocyte and oocyte activation, the oocyte's coat (the ZP) and the oocyte's plasma membrane seem to change quickly in order to initiate a fast block to a second spermatozoon (Part II). Sometimes, two spermatozoa fuse with one oocyte, an incidence of 1%-2%, resulting in polyploid fetuses that account for up to 10%-20% of spontaneously aborted human conceptuses. The present review aims to focus on the first part of the human sperm and oocyte interactions, emphasizing the latest molecular and cellular mechanisms controlling this process.

Functional signaling and gene regulatory networks between the oocyte and the surrounding cumulus cells.

PubMed

Biase, Fernando H; Kimble, Katelyn M

2018-05-10

The maturation and successful acquisition of developmental competence by an oocyte, the female gamete, during folliculogenesis is highly dependent on molecular interactions with somatic cells. Most of the cellular interactions identified, thus far, are modulated by growth factors, ions or metabolites. We hypothesized that this interaction is also modulated at the transcriptional level, which leads to the formation of gene regulatory networks between the oocyte and cumulus cells. We tested this hypothesis by analyzing transcriptome data from single oocytes and the surrounding cumulus cells collected from antral follicles employing an analytical framework to determine interdependencies at the transcript level. We overlapped our transcriptome data with putative protein-protein interactions and identified hundreds of ligand-receptor pairs that can transduce paracrine signaling between an oocyte and cumulus cells. We determined that 499 ligand-encoding genes expressed in oocytes and cumulus cells are functionally associated with transcription regulation (FDR < 0.05). Ligand-encoding genes with specific expression in oocytes or cumulus cells were enriched for biological functions that are likely associated with the coordinated formation of transzonal projections from cumulus cells that reach the oocyte's membrane. Thousands of gene pairs exhibit significant linear co-expression (absolute correlation > 0.85, FDR < 1.8 × 10 - 5 ) patterns between oocytes and cumulus cells. Hundreds of co-expressing genes showed clustering patterns associated with biological functions (FDR < 0.5) necessary for a coordinated function between the oocyte and cumulus cells during folliculogenesis (i.e. regulation of transcription, translation, apoptosis, cell differentiation and transport). Our analyses revealed a complex and functional gene regulatory circuit between the oocyte and surrounding cumulus cells. The regulatory profile of each cumulus-oocyte complex is likely associated with the oocytes' developmental potential to derive an embryo.

What do reproductive-age women who undergo oocyte cryopreservation think about the process as a means to preserve fertility?

PubMed

Hodes-Wertz, Brooke; Druckenmiller, Sarah; Smith, Meghan; Noyes, Nicole

2013-11-01

To better understand women's beliefs, priorities, and attitudes toward oocyte cryopreservation, to appreciate the extent of their reproductive education, and to track the reproductive paths of women who chose to undergo oocyte cryopreservation treatment. An anonymous 30-question survey. Not applicable. From 2005-2011, 478 women completed ≥1 oocyte cryopreservation treatment cycle at our center to defer reproduction. None. Demographics, motivations, desires, fertility knowledge, and outcomes related to oocyte cryopreservation. A total of 183 patients (38%) completed the survey with >80% being aged ≥35 years; white; having no partner at time of oocyte cryopreservation; undergoing oocyte cryopreservation after an optimal reproductive age; feeling they had improved their reproductive future after oocyte cryopreservation and being empowered by the process; aware of age-related infertility; sensing popular media falsely portrayed the upper age limit for natural conception; and recorded lack of partner as the primary rationale for not yet starting a family. Nineteen percent of respondents added that workplace inflexibility contributed to their reproductive dilemma. Half stated they learned about oocyte cryopreservation from a friend; others became aware through a medical provider, the media, and the internet. Most patients (93%) have not yet returned to use their frozen oocytes; 11 stated they had. Overall, 20% reported a successful conception after oocyte cryopreservation. Surveying oocyte cryopreservation patients provides a glimpse into the knowledge base and motivations surrounding current female reproductive practices. Oocyte cryopreservation technology may prove to bridge the gap between reproductive prime and when a woman is realistically "ready" to have children. Copyright © 2013 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Oocyte quality and estradiol supplementation affect in vitro maturation success in the white-tailed deer (Odocoileus virginianus).

PubMed

Siriaroonrat, B; Comizzoli, P; Songsasen, N; Monfort, S L; Wildt, D E; Pukazhenthi, B S

2010-01-01

White-tailed deer oocyte biology is not well documented. The objective of this study was to determine (1) the influence of estradiol (E(2)) supplementation on meiotic resumption and the ability to "rescue" poorer quality (lower grade) oocytes and (2) the kinetics of oocyte nuclear maturation in vitro in the white-tailed deer. In Experiment 1, immature oocytes harvested during hunting-culling operations were cultured for 24h in the presence or absence of E(2). Incubation in 1mug/mL E(2) promoted nuclear maturation (to telophase I, TI; or to metaphase II, MII) in a higher proportion of Grade 1 oocytes ( approximately 77%; P<0.05) compared with that in Grade 2 or Grade 3 counterparts ( approximately 51%). For Grades 2 and 3 oocytes, there was no advantage (P>0.05) for E(2) supplementation in reaching TI/MII. In Experiment 2, Grade 1 oocytes were cultured in the presence of E(2) and nuclear status evaluated at 0, 3, 6, 12, and 24h of in vitro incubation. At 0h,>70% of oocytes already had undergone germinal vesicle breakdown. After 12h, approximately 70% of oocytes had reached metaphase I of nuclear maturation, with approximately 75% achieving TI/MII by 24h in vitro. In summary, adding E(2) to an in vitro maturation (IVM) culture system for white-tailed deer was advantageous, but only for the highest quality oocytes, with approximately 75% achieving nuclear maturation. In contrast, E(2) supplement did not benefit lower-grade oocytes, half of which will reach MII, with the other half failing. Under the described culture conditions, good-quality white-tailed deer oocytes achieve nuclear maturation over a time duration comparable with that reported in other ungulates.

Comparison of sucrose and trehalose media modification as an update of oocyte vitrification: A study of apoptotic level

NASA Astrophysics Data System (ADS)

Lestari, Silvia W.; Fitriyah, Nurin N.; Pangestu, Mulyoto; Pratama, Gita; Margiana, Ria

2018-02-01

Number of women who are not being able to have offspring in their reproductive life is increasing which might be influenced by several factors. As a consequence, oocyte cryopreservation could be an ensuring solution for women fertility preservation. A good vitrification could be conducted by combining an appropriate of type and concentration of cryoprotectants. One of the marks of successful vitrification is the vitrified oocytes could avoid apoptosis. This study aimed to evaluate the modification of cryoprotectant media as un update of oocyte vitrification as follow: the combination and the concentration of cryoprotectant media of oocytes vitrification, based on their effects on the apoptosis or DNA damage of oocytes. A total of 84 MII stage oocytes from adult female Deutschland, Denken and Yoken (DDY) mice (7-8 weeks old) were used in this study. Vitrification procedure was performed by using VS1 contained 15% EG, 15% DMSO, 0.5 mol/l sucrose (Merck, Darmstadt, Germany) and VS2 contained 15% EG, 15% DMSO, 0.5 mol/l trehalose (Merck, Darmstadt, Germany) in HM. Furthermore, warming solution (WS) was divided into four groups. There were: WS1a contained 0.3 mol/l sucrose, WS1b contained 0.15 mol/l sucrose, WS2a contained 0.3 mol/l trehalose, and WS2b contained 0.15 mol/l trehalose. Apoptotic level was performed by staining the oocytes with TUNEL and propidium iodide (PI) based on Brison and Schultz method then examined under confocal microscope. The rate of apoptosis in oocytes after vitrification and warming was higher compared to the fresh control oocytes. Furthermore, the rate of apoptosis in the vitrified oocytes by sucrose media (28%) was higher compared to the vitrified oocytes by trehalose media (16%). The results of this study indicated that vitrification increased apoptosis in the vitrified oocytes related to the oocyte injury after vitrification. Moreover, the vitrification increased apoptosis more in the vitrified oocytes by sucrose media than the vitrified oocytes by trehalose media. The exposure to the 16.5% EG, 16.5% DMSO and 0.5 mol/l trehalose as cryoprotectant media decreased their viability and increased the number of DNA-fragmented nuclei in the oocytes, lesser than sucrose. Trehalose was proved to be the more suitable extracellular cryoprotectant media in oocyte vitrification based on the apoptotic level, compared to that of sucrose. A modification of cryoprotectant media as an update of oocyte vitrification consisted 0.5 mol/l trehalose concentration as extracellular cryoprotectant and combined with 16.5% EG and 16.5% DMSO as intracellular cryoprotectant has produced.

[Comparison of the frequency of chromosomal disorders in populations of in vitro-matured and ovulating rat oocytes].

PubMed

Kitaev, E M; Pimenova, M N

1980-12-01

The rat oocytes extracted from the rat ovaries and cultivated for 42-46 hours were compared with ovulated oocytes by the chromosomal aberration rate. The chromosomal aberration rate in the population of "follicular" oocytes was 8.2% on the average whereas in ovulated oocytes, it did not exceed 1.8%. Analysis of the chromosomal aberrations depending on the phase of the estral cycle suggests that the main portion of chromosomal aberrations in cultivated oocytes occurs during the physiological process of follicular atresia.

Chlorogenic acid supplementation during in vitro maturation improves maturation, fertilization and developmental competence of porcine oocytes.

PubMed

Nguyen, T-V; Tanihara, F; Do, Ltk; Sato, Y; Taniguchi, M; Takagi, M; Van Nguyen, T; Otoi, T

2017-12-01

Chlorogenic acid (CGA) is a quinic acid conjugate of caffeic acid, and a phytochemical found in many fruits and beverages that acts as an antioxidant. The present study investigated the effects of CGA supplementation during in vitro maturation (IVM), on in vitro development of porcine oocytes, to improve the porcine in vitro production (IVP) system. Oocytes were matured either without (control) or with CGA (10, 50, 100 and 200 μM). Subsequently, the matured oocytes were fertilized and cultured in vitro for 7 day. The rates of maturation, fertilization and blastocyst formation of oocytes matured with 50 μM CGA were significantly (p < .05) higher than those of the control oocytes. Hydrogen peroxide (H 2 O 2 ) is one of the reactive oxygen species and induces DNA damage in porcine oocytes. When oocytes were matured with 1 mM H 2 O 2 to assess the protective effect of CGA, 50 μM CGA supplementation improved the maturation rate and the proportion of DNA-fragmented nuclei in oocytes compared with control oocytes matured without CGA. Moreover, when oocytes were matured with either 50 μM CGA (control) or caffeic acid (10, 50 and 100 μM), the rates of maturation, fertilization and the blastocyst formation of oocytes matured with 50 μM CGA were similar to those of oocytes matured with 10 and 50 μM caffeic acid. Our results suggest that CGA has comparable effects to caffeic acid, and IVM with 50 μM CGA is particularly beneficial to IVP of porcine embryos and protects oocytes from DNA damage induced by oxidative stress. Supplementation of CGA to the maturation medium has a potential to improve porcine IVP system. © 2017 Blackwell Verlag GmbH.

G-protein coupled estrogen receptor (GPER) inhibits final oocyte maturation in common carp, Cyprinus carpio.

PubMed

Majumder, Suravi; Das, Sumana; Moulik, Sujata Roy; Mallick, Buddhadev; Pal, Puja; Mukherjee, Dilip

2015-01-15

GPR-30, now named as GPER (G protein-coupled estrogen receptor) was first identified as an orphan receptor and subsequently shown to be required for estrogen-mediated signaling in certain cancer cells. Later studies demonstrated that GPER has the characteristics of a high affinity estrogen membrane receptor on Atlantic croaker and zebra fish oocytes and mediates estrogen inhibition of oocyte maturation in these two distantly related teleost. To determine the broad application of these findings to other teleost, expression of GPER mRNA and its involvement in 17β-estradiol mediated inhibition of oocyte maturation in other cyprinid, Cyprinus carpio was investigated. Carp oocytes at pre-vitellogenic, late-vitellogenic and post-vitellogenic stages of development contained GPER mRNA and its transcribed protein with a maximum at late-vitellogenic oocytes. Ovarian follicular cells did not express GPER mRNA. Carp oocytes GPER mRNA was essentially identical to that found in other perciformes and cyprinid fish oocytes. Both spontaneous and 17,20β-dihydroxy-4-pregnen-3-one (17,20β-P)-induced oocyte maturation in carp was significantly decreased when they were incubated with either E2, or GPER agonist G-1. On the other hand spontaneous oocyte maturation was significantly increased when carp ovarian follicles were incubated with an aromatase inhibitor, fadrozole, GPER antagonist, G-15 and enzymatic removal of the ovarian follicle cell layers. This increase in oocyte maturation was partially reversed by co-treatment with E2. Consistent with previous findings with human and fish GPR30, E2 treatment in carp oocytes caused increase in cAMP production and simultaneously decrease in oocyte maturation, which was inhibited by the addition of 17,20β-P. The results suggest that E2 and GPER play a critical role in regulating re-entry in to meiotic cell cycle in carp oocytes. Copyright © 2014 Elsevier Inc. All rights reserved.

Generation of rats from vitrified oocytes with surrounding cumulus cells via in vitro fertilization with cryopreserved sperm.

PubMed

Fujiwara, Katsuyoshi; Kamoshita, Maki; Kato, Tsubasa; Ito, Junya; Kashiwazaki, Naomi

2017-01-01

The objective of this study was to evaluate fertility and full-term development of rat vitrified oocytes after in vitro fertilization (IVF) with cryopreserved sperm. Oocytes with or without surrounding cumulus cells were vitrified with 30% ethylene glycol + 0.5 mol/L sucrose + 20% fetal calf serum by using the Cryotop method. The warmed oocytes were co-cultured with sperm. Although the denuded/vitrified oocytes were not fertilized, some of the oocytes vitrified with cumulus cells were fertilized (32.7%) after IVF with fresh sperm. When IVF was performed with cryopreserved sperm, vitrified or fresh oocytes with cumulus cells were fertilized (62.9% or 41.1%, respectively). In addition, to confirm the full-term development of the vitrified oocytes with surrounding cumulus cells after IVF with cryopreserved sperm, 108 vitrified oocytes with two pronuclei (2PN) were transferred into eight pseudopregnant females, and eight pups were obtained from three recipients. The present work demonstrates that vitrified rat oocytes surrounded by cumulus cells can be fertilized in vitro with cryopreserved sperm, and that 2PN embryos derived from cryopreserved gametes can develop to term. To our knowledge, this is the first report of successful generation of rat offspring derived from vitrified oocytes that were fertilized in vitro with cryopreserved sperm. © 2016 Japanese Society of Animal Science.

The human cumulus--oocyte complex gene-expression profile

PubMed Central

Assou, Said; Anahory, Tal; Pantesco, Véronique; Le Carrour, Tanguy; Pellestor, Franck; Klein, Bernard; Reyftmann, Lionel; Dechaud, Hervé; De Vos, John; Hamamah, Samir

2006-01-01

BACKGROUND The understanding of the mechanisms regulating human oocyte maturation is still rudimentary. We have identified transcripts differentially expressed between immature and mature oocytes, and cumulus cells. METHODS Using oligonucleotides microarrays, genome wide gene expression was studied in pooled immature and mature oocytes or cumulus cells from patients who underwent IVF. RESULTS In addition to known genes such as DAZL, BMP15 or GDF9, oocytes upregulated 1514 genes. We show that PTTG3 and AURKC are respectively the securin and the Aurora kinase preferentially expressed during oocyte meiosis. Strikingly, oocytes overexpressed previously unreported growth factors such as TNFSF13/APRIL, FGF9, FGF14, and IL4, and transcription factors including OTX2, SOX15 and SOX30. Conversely, cumulus cells, in addition to known genes such as LHCGR or BMPR2, overexpressed cell-tocell signaling genes including TNFSF11/RANKL, numerous complement components, semaphorins (SEMA3A, SEMA6A, SEMA6D) and CD genes such as CD200. We also identified 52 genes progressively increasing during oocyte maturation, comprising CDC25A and SOCS7. CONCLUSION The identification of genes up and down regulated during oocyte maturation greatly improves our understanding of oocyte biology and will provide new markers that signal viable and competent oocytes. Furthermore, genes found expressed in cumulus cells are potential markers of granulosa cell tumors. PMID:16571642

Expression and localization of aquaporin 1b during oocyte development in the Japanese eel (Anguilla japonica)

PubMed Central

2011-01-01

To elucidate the molecular mechanisms underling hydration during oocyte maturation, we characterized the structure of Japanese eel (Anguilla japonica) novel-water selective aquaporin 1 (AQP1b) that thought to be involved in oocyte hydration. The aqp1b cDNA encodes a 263 amino acid protein that includes the six potential transmembrane domains and two Asn-Pro-Ala motifs. Reverse transcription-polymerase chain reaction showed transcription of Japanese eel aqp1b in ovary and testis but not in the other tissues. In situ hybridization studies with the eel aqp1b cRNA probe revealed intense eel aqp1b signal in the oocytes at the perinucleolus stage and the signals became faint during the process of oocyte development. Light microscopic immunocytochemical analysis of ovary revealed that the Japanese eel AQP1b was expressed in the cytoplasm around the yolk globules which were located in the peripheral region of oocytes during the primary yolk globule stage; thereafter, the immunoreactivity was observed throughout the cytoplasm of oocyte as vitellogenesis progressed. The immunoreactivity became localized around the large membrane-limited yolk masses which were formed by the fusion of yolk globules during the oocyte maturation phase. These results together indicate that AQP1b, which is synthesized in the oocyte during the process of oocyte growth, is essential for mediating water uptake into eel oocytes. PMID:21615964

Comparison of normal and abnormal fertilization of in vitro-matured human oocyte according to insemination method.

PubMed

Park, Ju Hee; Jee, Byung Chul; Kim, Seok Hyun

2016-04-01

Our purpose was to compare the normal fertilization rate, multi-pronuclei (PN) formation rate, and embryonic development of in vitro-matured oocytes between conventional insemination and intracytoplasmic sperm injection (ICSI). A total of 213 stimulated in vitro fertilization (IVF) cycles were selected, in which at least one immature oocyte was obtained (from 2010 to 2014). Immature oocytes were assigned to germinal vesicle (GV)-stage or metaphase I (MI)-stage oocyte groups. Cycles with obligatory ICSI due to male-factor infertility were excluded. Cycles were divided into two groups according to fertilization method: there were 97 cycles with conventional insemination and 116 cycles with ICSI. After in vitro maturation of 324 GV-stage oocytes and 341 MI-stage oocytes, the fertilization rate, multi-PN formation rate, and embryonic development were compared according to the fertilization method. The normal fertilization rate was similar in the conventional insemination and the ICSI both in GV-derived and MI-derived oocytes. Both fertilization methods resulted in a similar multi-PN formation rate in GV-derived oocytes; however, in MI-derived oocytes, the multi-PN formation rate was zero with ICSI and this was significantly lower than that with conventional insemination (9.6%, P = 0.001). In non-male-factor infertility, ICSI should be considered when MI oocytes are matured. © 2016 Japan Society of Obstetrics and Gynecology.

Developmental potential of murine germinal vesicle stage cumulus-oocyte complexes following exposure to dimethylsulphoxide or cryopreservation: loss of membrane integrity of cumulus cells after thawing.

PubMed

Ruppert-Lingham, C J; Paynter, S J; Godfrey, J; Fuller, B J; Shaw, R W

2003-02-01

Cumulus cells of the cumulus-oocyte complex (COC) are important in oocyte maturation. Thus, in preserving immature oocytes it is prudent to also preserve their associated cumulus cells. The survival and function of oocytes and their associated cumulus cells was assessed following cryopreservation or exposure to cryoprotectant without freezing. Immature COCs were collected from mice primed with pregnant mare's serum. COCs were either slow-cooled or exposed to 1.5 mol/l dimethylsulphoxide without freezing. Treated and fresh COCs were stained for membrane integrity or, after in-vitro maturation and IVF, were assessed for developmental capability. Development of cumulus-denuded fresh oocytes, as well as denuded and frozen-thawed oocytes co-cultured with fresh cumulus cells, was assessed. Slow-cooled oocytes had significantly reduced coverage by intact cumulus cells compared with fresh COCs. Cumulus cell association and developmental capability were not substantially affected by exposure to cryoprotectant without freezing. Denuded fresh oocytes and cryopreserved COCs had decreased developmental potential that was not overcome by co-culture with fresh cumulus cells. Loss of association between oocyte and cumulus cells was induced by cryopreservation, but not by treatment with cryoprotectant alone. The data indicate that direct physical contact between cumulus cells and the oocyte, throughout maturation, improves subsequent embryo development.

Metabolic regulation of oocyte cell death through the CaMKII-mediated phosphorylation of caspase-2.

PubMed

Nutt, Leta K; Margolis, Seth S; Jensen, Mette; Herman, Catherine E; Dunphy, William G; Rathmell, Jeffrey C; Kornbluth, Sally

2005-10-07

Vertebrate female reproduction is limited by the oocyte stockpiles acquired during embryonic development. These are gradually depleted over the organism's lifetime through the process of apoptosis. The timer that triggers this cell death is yet to be identified. We used the Xenopus egg/oocyte system to examine the hypothesis that nutrient stores can regulate oocyte viability. We show that pentose-phosphate-pathway generation of NADPH is critical for oocyte survival and that the target of this regulation is caspase-2, previously shown to be required for oocyte death in mice. Pentose-phosphate-pathway-mediated inhibition of cell death was due to the inhibitory phosphorylation of caspase-2 by calcium/calmodulin-dependent protein kinase II (CaMKII). These data suggest that exhaustion of oocyte nutrients, resulting in an inability to generate NADPH, may contribute to ooctye apoptosis. These data also provide unexpected links between oocyte metabolism, CaMKII, and caspase-2.

Histoarchitecture of the Ovary of Rhipicephalus (Boophilus) annulatus during Pre- and Postengorgement Period

PubMed Central

Kanapadinchareveetil, Sreelekha; Chandrasekhar, Leena; Gopi, Jyothimol; Ranjan Lenka, Dibya; Vasu, Aswathi; KGopalan, Ajith Kumar; Nair, Suresh N.; Juliet, Sanis; Ghosh, Srikanta

2015-01-01

The present communication describes the detailed day wise study of histological changes of the ovary of Rhipicephalus (Boophilus) annulatus in the postengorgement period together with the systematic classification of their oocytes. The ovary of R. (B.) annulatus is panoistic type with an asynchronous development of oocytes. All the stages (II, III, IV, and V) of oocytes except stage I were similar to R. (B.) microplus. The stage I oocytes showed basophilia, which was not reported earlier in other species of ticks. Day wise changes were in the form of presence of oogonia in partially fed and day one engorged adults, considerable degeneration of oocytes on day two, emergence of new wave of oocytes on day three, presence of mature oocytes up to day eight, and complete degeneration of ovarian tissue from day eight onwards. The degenerative changes in the ovary appeared initially in the oocytes followed by germinal epithelium. PMID:25664337

Histoarchitecture of the ovary of Rhipicephalus (Boophilus) annulatus during pre- and postengorgement period.

PubMed

Kanapadinchareveetil, Sreelekha; Chandrasekhar, Leena; Gopi, Jyothimol; Lenka, Dibya Ranjan; Vasu, Aswathi; KGopalan, Ajith Kumar; Nair, Suresh N; Ravindran, Reghu; Juliet, Sanis; Ghosh, Srikanta

2015-01-01

The present communication describes the detailed day wise study of histological changes of the ovary of Rhipicephalus (Boophilus) annulatus in the postengorgement period together with the systematic classification of their oocytes. The ovary of R. (B.) annulatus is panoistic type with an asynchronous development of oocytes. All the stages (II, III, IV, and V) of oocytes except stage I were similar to R. (B.) microplus. The stage I oocytes showed basophilia, which was not reported earlier in other species of ticks. Day wise changes were in the form of presence of oogonia in partially fed and day one engorged adults, considerable degeneration of oocytes on day two, emergence of new wave of oocytes on day three, presence of mature oocytes up to day eight, and complete degeneration of ovarian tissue from day eight onwards. The degenerative changes in the ovary appeared initially in the oocytes followed by germinal epithelium.

SIRT1, 2, 3 protect mouse oocytes from postovulatory aging.

PubMed

Zhang, Teng; Zhou, Yang; Li, Li; Wang, Hong-Hui; Ma, Xue-Shan; Qian, Wei-Ping; Shen, Wei; Schatten, Heide; Sun, Qing-Yuan

2016-04-01

The quality of metaphase II oocytes will undergo a time-dependent deterioration following ovulation as the result of the oocyte aging process. In this study, we determined that the expression of sirtuin family members (SIRT1, 2, 3) was dramatically reduced in mouse oocytes aged in vivo or in vitro. Increased intracellular ROS was observed when SIRT1, 2, 3 activity was inhibited. Increased frequency of spindle defects and disturbed distribution of mitochondria were also observed in MII oocytes aged in vitro after treatment with Nicotinamide (NAM), indicating that inhibition of SIRT1, 2, 3 may accelerate postovulatory oocyte aging. Interestingly, when MII oocytes were exposed to caffeine, the decline of SIRT1, 2, 3 mRNA levels was delayed and the aging-associated defective phenotypes could be improved. The results suggest that the SIRT1, 2, 3 pathway may play a potential protective role against postovulatory oocyte aging by controlling ROS generation.

Oocyte vitrification for elective fertility preservation: the past, present, and future.

PubMed

Gunnala, Vinay; Schattman, Glenn

2017-02-01

Oocyte cryopreservation is no longer experimental and one of its rapidly growing indications is elective fertility preservation. Currently there is no sufficient evidence to support its practice and therefore its place in IVF remains uncertain. Vitrification has superior post-thaw survival and fertilization outcomes compared with oocytes that were frozen with the slow-freeze technique. Oocyte vitrification produces similar IVF outcomes compared with fresh oocytes and is not associated with further obstetrical or perinatal morbidity. Undergoing elective oocyte cryopreservation between ages 35 and 37 will optimize live birth rates as well as cost effectiveness from mathematical models. In women who delay child bearing, elective oocyte cryopreservation in the mid 30s may be beneficial in terms of live birth rates and cost effectiveness. Prospective studies of women who have undergone oocyte cryopreservation and are now attempting conception are needed before official recommendations can be made regarding elective egg freezing.

Stereological comparison of oocyte recruitment and batch fecundity estimates from paraffin and resin sections using spawning albacore (Thunnus alalunga) ovaries as a case study

NASA Astrophysics Data System (ADS)

Saber, Sámar; Macías, David; Ortiz de Urbina, Josetxu; Kjesbu, Olav Sigurd

2015-01-01

Traditional histological protocols in marine fish reproductive laboratories using paraffin as the embedding medium are now increasingly being replaced with protocols using resin instead. These procedures entail different degrees of tissue shrinkage complicating direct comparisons of measurement results across laboratories or articles. In this work we selected ovaries of spawning Mediterranean albacore (Thunnus alalunga) as the subject of our study to address the issue of structural changes, by contrasting values on oocyte recruitment and final batch fecundity given from the same tissue samples in both paraffin and resin. A modern stereological method, the oocyte packing density (OPD) theory, was used supported by initial studies on ovarian tissue sampling and measurement design. Examples of differences in the volume fraction of oocyte stages, free space and connective tissue were found between the embedding media. Mean oocyte diameters were smaller in paraffin than in resin with differences ranging between 0.5% in primary growth and 24.3% in hydration (HYD) stage oocytes. Fresh oocyte measurements showed that oocytes shrank as a consequence of the embedding process, reaching the maximal degree of shrinkage for oocytes in the HYD stage (45.8% in paraffin and 26.5% in resin). In order to assess the effect of oocyte shrinkage on the OPD result, and thereby on relative batch fecundity (Fr), oocyte diameters corrected and uncorrected for shrinkage, were used for estimations. Statistical significant differences were found (P < 0.05) between these two approaches in both embedding media. The average Fr was numerically smaller in paraffin compared to resin (86 ± 61 vs. 106 ± 54 oocytes per gram of body mass (mean ± SD)). For both embedding media statistical significant differences (P < 0.05) were seen between Fr results based on either oocytes in the germinal vesicle migration stage or HYD stage. As a valuable adjunct, the present use of the OPD theory made it possible to document that the oocyte recruitment of spawning ovaries of Mediterranean albacore followed the typical pattern of an asynchronous oocyte development and indeterminate fecundity.

IGF-I slightly improves nuclear maturation and cleavage rate of bovine oocytes exposed to acute heat shock in vitro.

PubMed

Meiyu, Qi; Liu, Di; Roth, Zvi

2015-08-01

An in vitro model of embryo production was used to examine the effects of insulin-like growth factor (IGF)-I on maturation and developmental competence of oocytes exposed to heat shock. Cumulus-oocyte complexes were matured at 38.5°C or exposed to acute heat shock (HS; 41.5°C), with or without 100 ng/ml IGF-I, for 22 h through in vitro maturation. The experimental groups were control (C), C + IGF-I, HS, and HS + IGF-I. Oocytes were fertilized at the end of maturation, and the proportion of cleaved embryos was recorded 44 h later. HS during maturation increased the proportion of TUNEL-positive oocytes (P < 0.05). HS did not have any effect on cortical granule translocation but impaired resumption of meiosis, expressed as a decreased proportion of oocytes with nuclei in metaphase I (P < 0.05) and metaphase II (MII; P < 0.05). HS decreased the proportion of oocytes that cleaved (P < 0.05), in particular those oocytes that further developed to 4-cell-stage embryos (P < 0.05). IGF-I alleviated, to some extent, the deleterious effects of HS on the oocytes as reflected by a reduced proportion of TUNEL-positive oocytes (P < 0.03). While not significant, IGF-I tended to increase the proportion of MII-stage oocytes (P < 0.08) and 4-cell-stage cleaved embryos (P < 0.06). Further examination is required to explore whether IGF-I also affects the developmental competence of oocytes exposed to HS.

Comparison of the effects of BPA and BPAF on oocyte spindle assembly and polar body release in mice.

PubMed

Nakano, Kei; Nishio, Manami; Kobayashi, Norio; Hiradate, Yuuki; Hoshino, Yumi; Sato, Eimei; Tanemura, Kentaro

2016-04-01

Bisphenol AF (BPAF), a homolog of bisphenol A (BPA), is a widely used environmental chemical that has adverse effects on reproduction. The aim of this study was to analyse the effects of BPA and BPAF exposure on oocyte maturation in vitro. Oocytes were cultured in the presence of BPA or BPAF (2, 20, 50 or 100 μg/ml) for 18 h. At concentrations of 50 and 100 μg/ml, BPA and BPAF inhibited oocyte maturation, with BPAF treatment causing a sharp decrease in the number of oocytes reaching maturity. Oocytes were exposed to BPA or BPAF at 2 μg/ml and cultured for different durations (6, 9, 12, 15 or 18 h). Both BPAF and BPA caused a cell cycle delay under these conditions. Oocytes cultured in the presence of BPA or BPAF (50 μg/ml) for 21 h were tested for the localization of α-tubulin and MAD2 using immunofluorescence. High concentrations of BPAF induced cell cycle arrest through the activation of the spindle assembly checkpoint. After 12 h of culture in BPAF (50 μg/ml), oocytes were transferred to control medium for 9 h. Only 63.3% oocytes treated in this manner progressed to metaphase II (MII). Oocytes exposed to high doses of BPA experienced a cell cycle delay, but managed to progress to MII when the culture period was prolonged. In addition, MAD2 was localized in the cytoplasm of these oocytes. In conclusion, both BPAF and BPA exposure affected oocyte maturation, however BPAF and BPA have differential effects on SAC activity.

Oocytes with a dark zona pellucida demonstrate lower fertilization, implantation and clinical pregnancy rates in IVF/ICSI cycles.

PubMed

Shi, Wei; Xu, Bo; Wu, Li-Min; Jin, Ren-Tao; Luan, Hong-Bing; Luo, Li-Hua; Zhu, Qing; Johansson, Lars; Liu, Yu-Sheng; Tong, Xian-Hong

2014-01-01

The morphological assessment of oocytes is important for embryologists to identify and select MII oocytes in IVF/ICSI cycles. Dysmorphism of oocytes decreases viability and the developmental potential of oocytes as well as the clinical pregnancy rate. Several reports have suggested that oocytes with a dark zona pellucida (DZP) correlate with the outcome of IVF treatment. However, the effect of DZP on oocyte quality, fertilization, implantation, and pregnancy outcome were not investigated in detail. In this study, a retrospective analysis was performed in 268 infertile patients with fallopian tube obstruction and/or male factor infertility. In 204 of these patients, all oocytes were surrounded by a normal zona pellucida (NZP, control group), whereas 46 patients were found to have part of their retrieved oocytes enclosed by NZP and the other by DZP (Group A). In addition, all oocytes enclosed by DZP were retrieved from 18 patients (Group B). No differences were detected between the control and group A. Compared to the control group, the rates of fertilization, good quality embryos, implantation and clinical pregnancy were significantly decreased in group B. Furthermore, mitochondria in oocytes with a DZP in both of the two study groups (A and B) were severely damaged with several ultrastructural alterations, which were associated with an increased density of the zona pellucida and vacuolization. Briefly, oocytes with a DZP affected the clinical outcome in IVF/ICSI cycles and appeared to contain more ultrastructural alterations. Thus, DZP could be used as a potential selective marker for embryologists during daily laboratory work.

Develop to Term Rat Oocytes Injected with Heat-Dried Sperm Heads

PubMed Central

Lee, Kyung-Bon; Park, Ki-Eun; Kwon, In-Kiu; Tripurani, Swamy K.; Kim, Keun Jung; Lee, Ji Hye; Niwa, Koji; Kim, Min Kyu

2013-01-01

This study investigated the development of rat oocytes in vitro and in vivo following intracytoplasmic injection of heads from spermatozoa heat-dried at 50°C for 8 h and stored at 4°C in different gas phases. Sperm membrane and chromosome are damaged by the process of heat-drying. Oocyte activation and cleavage of oocytes were worse in oocytes injected with spermatozoa heat-dried and stored for 1 week than unheated, fresh spermatozoa, but in heat-dried spermatozoa, there were no differences in these abilities of oocytes between the samples stored in nitrogen gas and in air. The oocytes injected with heat-dried spermatozoa stored for 1 week could develop to the morula and blastocyst stages without difference between the samples stored in nitrogen gas and in air after artificial stimulation. Cleavage of oocytes and development of cleaved embryos were higher when heat-dried spermatozoa were stored for 3 and 6 months in nitrogen gas than in air. However, the ability of injected oocytes to develop to the morula and blastocyst stages was not inhibited even when heat-dried spermatozoa stored in both atmosphere conditions for as long as 6 months were used. When 2-cell embryos derived from oocytes injected with heads from spermatozoa heat-dried and stored for 1 week and 1 month were transferred, each 1 of 4 recipients was conceived, and the conceived recipients delivered 1 live young each. These results demonstrate that rat oocytes can be fertilized with heat-dried spermatozoa and that the fertilized oocytes can develop to term. PMID:24223784

The dynamic pattern of PLIN3 in pig oocytes and cumulus cells during in vitro maturation.

PubMed

Xu, Mingzhu; Zeng, Yaqiong; Chi, Daming; Si, Linan; Qu, Xiao; Li, Juan

2018-02-01

Lipid droplets (LDs) are the main energy resource for porcine preimplantation embryonic development. PLIN3 has been implicated in LD formation and regulation. Therefore, this study aimed to detect the dynamic pattern of PLIN3 in pig oocytes and cumulus cells (CC) during in vitro maturation (IVM), and to determine the relationship between PLIN3 and LD content. IVM with cumulus-enclosed oocytes (CEO), cumulus-denuded oocytes (DO) and the CCs denuded from the corresponding oocytes (DCC) was performed in porcine follicular fluid (PFF) or PFF-free optimized medium. DO and the DCC were cultured together under the same conditions as described above, while the DO was named DTO and the DCC was named DTCC in this group. Firstly, our results revealed LDs distributed widely in oocytes and CC, while the PLIN3 protein coated these LDs and spread out ubiquitously in the cytoplasm. Secondly, not only the mRNA level but also at protein level of PLIN3 in immature naked oocytes (IO) was higher than that in matured CEO, DO and DTO. Although PLIN3 was expressed at lower levels in CC from immature oocytes (ICC), the protein level of PLIN3 was comparably higher in the ECC and DCC groups. The triglyceride (TG) content in CEO and DO was significantly less abundant compared with that in IO. Therefore, our results indicated that co-culturing of oocytes and CC might affect PLIN3 expression levels in CC but not in oocytes. Lipid accumulation in pig oocytes during maturation might be affected by PLIN3 cross-talk between oocytes and CC.

Application of EU tissue and cell directive screening protocols to anonymous oocyte donors in western Ukraine: data from an Irish IVF programme.

PubMed

Walsh, A P H; Omar, A B; Collins, G S; Murray, G U; Walsh, D J; Salma, U; Sills, E Scott

2010-01-01

Anonymous oocyte donation in the EU proceeds only after rigorous screening designed to ensure gamete safety. If anonymous donor gametes originating from outside EU territory are used by EU patients, donor testing must conform to the same standards as if gamete procurement had occurred in the EU. In Ireland, IVF recipients can be matched to anonymous donors in the Ukraine (a non-EU country). This investigation describes the evolution of anonymous oocyte donor screening methods during this period and associated results. Data were reviewed for all participants in an anonymous donor oocyte IVF programme from 2006 to 2009, when testing consistent with contemporary EU screening requirements was performed on all Ukrainian oocyte donors. HIV and hepatitis tests were aggregated from 314 anonymous oocyte donors and 265 recipients. The results included 5,524 Ukrainian women who were interviewed and 314 of these entered the programme (5.7% accession rate). Mean age of anonymous oocyte donors was 27.9 years; all had achieved at least one delivery. No case of hepatitis or HIV was detected at initial screening or at oocyte procurement. This is the first study of HIV and hepatitis incidence specifically among Ukrainian oocyte donors. We find anonymous oocyte donors to be a low-risk group, despite a high background HIV rate. Following full disclosure of the donation process, most Ukrainian women wishing to volunteer as anonymous oocyte donors do not participate. Current EU screening requirements appear adequate to maintain patient safety in the context of anonymous donor oocyte IVF.

Multiple Mechanisms Cooperate to Constitutively Exclude the Transcriptional Co-Activator YAP from the Nucleus During Murine Oogenesis1

PubMed Central

Abbassi, Laleh; Malki, Safia; Cockburn, Katie; Macaulay, Angus; Robert, Claude; Rossant, Janet; Clarke, Hugh J.

2016-01-01

Reproduction depends on the generation of healthy oocytes. Improving therapeutic strategies to prolong or rescue fertility depends on identifying the inter- and intracellular mechanisms that direct oocyte development under physiological conditions. Growth and proliferation of multiple cell types is regulated by the Hippo signaling pathway, whose chief effectors are the transcriptional co-activator YAP and its paralogue WWTR1. To resolve conflicting results concerning the potential role of Hippo in mammalian oocyte development, we systematically investigated the expression and localization of YAP in mouse oocytes. We report that that YAP is expressed in the germ cells beginning as early as Embryonic Day 15.5 and subsequently throughout pre- and postnatal oocyte development. However, YAP is restricted to the cytoplasm at all stages. YAP is phosphorylated at serine-112 in growing and fully grown oocytes, identifying a likely mechanistic basis for its nuclear exclusion, and becomes dephosphorylated at this site during meiotic maturation. Phosphorylation at serine-112 is regulated by a mechanism dependent on cyclic AMP and protein kinase A, which is known to be active in oocytes prior to maturation. Growing oocytes also contain a subpopulation of YAP, likely dephosphorylated, that is able enter the oocyte nucleus, but it is not retained there, implying that oocytes lack the cofactors required to retain YAP in the nucleus. Thus, although YAP is expressed throughout oocyte development, phosphorylation-dependent and -independent mechanisms cooperate to ensure that it does not accumulate in the nucleus. We conclude that nuclear YAP does not play a significant physiological role during oocyte development in mammals. PMID:26985001

Contributions of UBE2C and UBE2S to meiotic progression of porcine oocytes.

PubMed

Fujioka, Yoshie A; Onuma, Asuka; Fujii, Wataru; Sugiura, Koji; Naito, Kunihiko

2018-06-22

Vertebrate oocytes arrested at the first meiotic prophase must proceed to the second meiotic metaphase (MII) before fertilization. This meiotic process requires the precise control of protein degradation. Part of the protein degradation in oocytes is controlled by members of the ubiquitin-conjugating enzyme family, UBE2C and UBE2S, which are known to participate in mono-ubiquitination and poly-ubiquitination, respectively. Although UBE2 enzymes have been well studied in mitosis, their contribution to mammalian oocyte meiosis is relatively unknown and has been studied only in mice. Here, we investigated the contribution of UBE2C and UBE2S to porcine oocyte maturation using an RNA injection method. Overexpression of UBE2S prevented MII arrest of oocytes and led to the formation of a pronucleus (PN) at 48 h of culture. This effect was also observed for prolonged cultures of UBE2C-overexpressing oocytes, suggesting the effectiveness of poly-ubiquitination in the rapid escape from M-phase in porcine oocytes. Although the inhibition of either UBE2C or UBE2S by antisense RNA (asRNA) injection had no effect on oocyte maturation, asRNA-injected oocytes showed inhibited PN formation after parthenogenetic activation. These results indicated that ubiquitination of certain factors by UBE2S and UBE2C plays a role in the escape from MII arrest in porcine oocytes. Further investigations to identify the factors and how mono- and/or poly-ubiquitination contributes to protein degradation could provide a better understanding of UBE2 roles in oocyte maturation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoneda, Akihiro, E-mail: ayoneda@sci.hokudai.ac.jp; Division of Molecular Therapeutics, Center for Food & Medical Innovation, Hokkaido University; Watanabe, Tomomasa

In mammals, phospholipase Cζ (PLCζ) has the ability to trigger calcium (Ca{sup 2+}) oscillations in oocytes, leading to oocyte activation. Although there is a species-specific difference in the PLCζ-induced Ca{sup 2+} oscillatory pattern, whether PLCζ-induced Ca{sup 2+} oscillations affect preimplantation embryonic development remains unclear. Here, we show that Ca{sup 2+} oscillations in mouse PLCζ cRNA-injected oocytes stopped just before pronuclear formation, while that in porcine PLCζ cRNA-injected oocytes continued for several hours after pronuclei had been formed. This difference of Ca{sup 2+} oscillations in oocytes after pronuclear formation was dependent on the difference in the nuclear localization signal (NLS) sequencemore » of PLCζ between the mouse and pig. However, mouse and porcine PLCζ cRNA-injected oocytes parthenogenetically developed to blastocysts regardless of the absence or presence of Ca{sup 2+} oscillations after pronuclear formation. Furthermore, the developmental rate of mouse or porcine PLCζ-activated oocytes injected with round spermatids to the blastocyst stage was not significantly different from that of strontium-activated oocytes injected with round spermatids. These results suggest that the PLCζ-induced Ca{sup 2+} oscillatory pattern in mouse oocytes is dependent on the NLS sequence of PLCζ and injection of PLCζ may be a useful method for activation of round spermatid-injected and somatic nuclear transferred oocytes. - Highlights: • Porcine PLCζ-induced Ca{sup 2+} oscillations continued after pronuclear formation. • The Ca{sup 2+} oscillatory pattern was dependent on the difference in the NLS sequence of PLCζ. • PLCζ-activated oocytes parthenogenetically developed to blastocysts. • PLCζ-activated oocytes injected with round spermatids developed to blastocysts.« less

Laser-assisted in vitro fertilization facilitates fertilization of vitrified-warmed C57BL/6 mouse oocytes with fresh and frozen-thawed spermatozoa, producing live pups.

PubMed

Woods, Stephanie E; Qi, Peimin; Rosalia, Elizabeth; Chavarria, Tony; Discua, Allan; Mkandawire, John; Fox, James G; García, Alexis

2014-01-01

The utility of cryopreserved mouse gametes for reproduction of transgenic mice depends on development of assisted reproductive technologies, including vitrification of unfertilized mouse oocytes. Due to hardening of the zona pellucida, spermatozoa are often unable to penetrate vitrified-warmed (V-W) oocytes. Laser-assisted in vitro fertilization (LAIVF) facilitates fertilization by allowing easier penetration of spermatozoa through a perforation in the zona. We investigated the efficiency of V-W C57BL/6NTac oocytes drilled by the XYClone laser, compared to fresh oocytes. By using DAP213 for cryoprotection, 83% (1,470/1,762) of vitrified oocytes were recovered after warming and 78% were viable. Four groups were evaluated for two-cell embryo and live offspring efficiency: 1) LAIVF using V-W oocytes, 2) LAIVF using fresh oocytes, 3) conventional IVF using V-W oocytes and 4) conventional IVF using fresh oocytes. First, the groups were tested using fresh C57BL/6NTac spermatozoa (74% motile, 15 million/ml). LAIVF markedly improved the two-cell embryo efficiency using both V-W (76%, 229/298) and fresh oocytes (69%, 135/197), compared to conventional IVF (7%, 12/182; 6%, 14/235, respectively). Then, frozen-thawed C57BL/6NTac spermatozoa (35% motile, 15 million/ml) were used and LAIVF was again found to enhance fertilization efficiency, with two-cell embryo rates of 87% (298/343) using V-W oocytes (P<0.05, compared to fresh spermatozoa), and 73% (195/266) using fresh oocytes. Conventional IVF with frozen-thawed spermatozoa using V-W (6%, 10/168) and fresh (5%, 15/323) oocytes produced few two-cell embryos. Although live offspring efficiency following embryo transfer was greater with conventional IVF (35%, 18/51; LAIVF: 6%, 50/784), advantage was seen with LAIVF in live offspring obtained from total oocytes (5%, 50/1,010; conventional IVF: 2%, 18/908). Our results demonstrated that zona-drilled V-W mouse oocytes can be used for IVF procedures using both fresh and frozen-thawed spermatozoa, producing live pups. The ability to cryopreserve mouse gametes for LAIVF may facilitate management of large-scale transgenic mouse production facilities.

Assessment of Mouse Germinal Vesicle Stage Oocyte Quality by Evaluating the Cumulus Layer, Zona Pellucida, and Perivitelline Space

PubMed Central

Liu, Ying-Lei; Chen, Ying; Zhou, Cheng-Jie; Wu, Sha-Na; Shen, Jiang-Peng; Liang, Cheng-Guang

2014-01-01

To improve the outcome of assisted reproductive technology (ART) for patients with ovulation problems, it is necessary to retrieve and select germinal vesicle (GV) stage oocytes with high developmental potential. Oocytes with high developmental potential are characterized by their ability to undergo proper maturation, fertilization, and embryo development. In this study, we analyzed morphological traits of GV stage mouse oocytes, including cumulus cell layer thickness, zona pellucida thickness, and perivitelline space width. Then, we assessed the corresponding developmental potential of each of these oocytes and found that it varies across the range measured for each morphological trait. Furthermore, by manipulating these morphological traits in vitro, we were able to determine the influence of morphological variation on oocyte developmental potential. Manually altering the thickness of the cumulus layer showed strong effects on the fertilization and embryo development potentials of oocytes, whereas manipulation of zona pellucida thickness effected the oocyte maturation potential. Our results provide a systematic detailed method for selecting GV stage oocytes based on a morphological assessment approach that would benefit for several downstream ART applications. PMID:25144310

Developmental Arrest and Mouse Antral Not-Surrounded Nucleolus Oocytes1

PubMed Central

Monti, Manuela; Zanoni, Mario; Calligaro, Alberto; Ko, Minoru S.H.; Mauri, Pierluigi; Redi, Carlo Alberto

2013-01-01

ABSTRACT The antral compartment in the ovary consists of two populations of oocytes that differ by their ability to resume meiosis and to develop to the blastocyst stage. For reasons still not entirely clear, antral oocytes termed surrounded nucleolus (SN; 70% of the population of antral oocytes) develop to the blastocyst stage, whereas those called not-surrounded nucleolus (NSN) arrest at two cells. We profiled transcriptomic, proteomic, and morphological characteristics of antral oocytes and observed that NSN oocyte arrest is associated with lack of cytoplasmic lattices coincident with reduced expression of MATER and ribosomal proteins. Cytoplasmic lattices have been shown to store maternally derived mRNA and ribosomes in mammalian oocytes and embryos, and MATER has been shown to be required for cytoplasmic lattice formation. Thus, we isolated antral oocytes from a Matertm/tm mouse and we observed that 84% of oocytes are of the NSN type. Our results provide the first molecular evidence to account for inability of NSN-derived embryos to progress beyond the two-cell stage; these results may be relevant to naturally occurring preimplantation embryo demise in mammals. PMID:23136301

A Flexure-Guided Piezo Drill for Penetrating the Zona Pellucida of Mammalian Oocytes.

PubMed

Johnson, Wesley; Dai, Changsheng; Liu, Jun; Wang, Xian; Luu, Devin K; Zhang, Zhuoran; Ru, Changhai; Zhou, Chao; Tan, Min; Pu, Huayan; Xie, Shaorong; Peng, Yan; Luo, Jun; Sun, Yu

2018-03-01

Mammalian oocytes such as mouse oocytes have a highly elastic outer membrane, zona pellucida (ZP) that cannot be penetrated without significantly deforming the oocyte, even with a sharp micropipette. Piezo drill devices leverage lateral and axial vibration of the micropipette to accomplish ZP penetration with greatly reduced oocyte deformation. However, existing piezo drills all rely on a large lateral micropipette vibration amplitude ( 20 ) and a small axial vibration amplitude (0.1 ). The very large lateral vibration amplitude has been deemed to be necessary for ZP penetration although it also induces larger oocyte deformation and more oocyte damage. This paper reports on a new piezo drill device that uses a flexure guidance mechanism and a systematically designed pulse train with an appropriate base frequency. Both simulation and experimental results demonstrate that a small lateral vibration amplitude (e.g., 2 ) and an axial vibration amplitude as large as 1.2 were achieved. Besides achieving 100% effectiveness in the penetration of mouse oocytes (n = 45), the new piezo device during ZP penetration induced a small oocyte deformation of 3.4 versus larger than 10 using existing piezo drill devices.

A successful healthy live birth from a female patient with hypogonadotropic hypogonadism and oocytes with unusually large cytoplasmic inclusions.

PubMed

Duvan, Candan İltemir; Pekel, Aslıhan; Ercan, Ummu Gulsum; Arıkan, Yuksel Onaran

2016-03-01

This study aimed to report the case of a successful live birth from a woman having oocytes with abnormally large cytoplasmic inclusions. The patient described in this case is a 28 year-old woman with hypogonadotropic hypogonadism (HH) with a history of two previous unsuccessful in vitro fertilization (IVF) attempts offered an antagonist protocol. Stimulation was performed with human menopausal gonadotropin 300 IU/day. The intracytoplasmic sperm injection (ICSI) procedure was performed 4-6 hours after oocyte aspiration for all mature oocytes. Six oocytes were retrieved, five of which mature (MII). All oocytes had abnormal cytoplasmic structures. Two were fertilized after ICSI and two top quality embryos were transferred on Day 2. Our case report suggests that HH patients with refractile bodies/lipofuscin in their oocytes may not have their pregnancies negatively affected. While there have been several reports of successful births from dysmorphic oocytes, no cases of successful pregnancies followed by live births from young women with HH and oocytes with large cytoplasmic inclusions had been reported to date.

Src-family Tyrosine Kinases in Oogenesis, Oocyte Maturation, and Fertilization: An Evolutionary Perspective

PubMed Central

Kinsey, William H.

2015-01-01

The oocyte is a highly specialized cell poised to respond to fertilization with a unique set of actions needed to recognize and incorporate a single sperm, complete meiosis, reprogram maternal and paternal genomes and assemble them into a unique zygotic genome, and finally initiate the mitotic cell cycle. Oocytes accomplish this diverse series of events through an array of signal transduction pathway components that include a characteristic collection of protein tyrosine kinases. The src-family protein kinases figure importantly in this signaling array and oocytes characteristically express certain SFKs at high levels to provide for the unique actions that the oocyte must perform. The SFKs typically exhibit a distinct pattern of subcellular localization in oocytes and perform critical functions in different subcellular compartments at different steps during oocyte maturation and fertilization. While many aspects of SFK signaling are conserved among oocytes from different species, significant differences exist in the extent to which src-family -mediated pathways are used by oocytes from species that fertilize externally vs those which are fertilized internally. The observation that several oocyte functions which require SFK signaling appear to represent common points of failure during assisted reproductive techniques in humans, highlights the importance of these signaling pathways for human reproductive health. PMID:25030759

Characterization of urea transport in Bufo arenarum oocytes.

PubMed

Silberstein, Claudia; Zotta, Elsa; Ripoche, Pierre; Ibarra, Cristina

2003-07-01

Xenopus laevis oocytes have been extensively used for expression cloning, structure/function relationships, and regulation analysis of transporter proteins. Urea transporters have been expressed in Xenopus oocytes and their properties have been described. In order to establish an alternative system in which urea transporters could be efficiently expressed and studied, we determined the urea transport properties of ovarian oocytes from Bufo arenarum, a toad species common in Argentina. Bufo oocytes presented a high urea permeability of 22.3 x 10(-6) cm/s, which was significantly inhibited by the incubation with phloretin. The urea uptake in these oocytes was also inhibited by mercurial reagents, and high-affinity urea analogues. The urea uptake was not sodium dependent. The activation energy was 3.2 Kcal/mol, suggesting that urea movement across membrane oocytes may be through a facilitated urea transporter. In contrast, Bufo oocytes showed a low permeability for mannitol and glycerol. From these results, we propose that one or several specific urea transporters are present in ovarian oocytes from Bufo arenarum. Therefore, these oocytes cannot be used in expression studies of foreign urea transporters. The importance of Bufo urea transporter is not known but could be implicated in osmotic regulation during the laying of eggs in water. Copyright 2003 Wiley-Liss, Inc.

Quercetin supplemented diet improves follicular development, oocyte quality, and reduces ovarian apoptosis in rabbits during summer heat stress.

PubMed

Naseer, Zahid; Ahmad, Ejaz; Epikmen, Erkmen Tuğrul; Uçan, Uğur; Boyacioğlu, Murat; İpek, Emrah; Akosy, Melih

2017-07-01

The present study was designed to test the modulatory effect of dietary quercetin on follicle population, apoptosis, in vitro maturation rate and quality of oocytes in heat stressed female rabbits. A total of thirty-four New Zealand White heat stress (HS) exposed female rabbits were either fed with quercetin supplemented diet (QU-HS) or non-supplemented (HS) diet. Firstly, laparotomy was performed for oocyte retrieval and then, oocyte grading and COCs dimensional assessments were conducted. The A and B-grade oocytes were submitted for in vitro maturation. Thereafter, the ovaries were collected from rabbits and were processed for follicular population estimation and granulosa cells apoptosis. The results showed that follicle number, retrieved oocytes and A-grade oocytes were higher in QU-HS, comparatively. A significant difference was observed in A-grade oocytes dimensions between QU-HS and HS treatment groups. The oocyte maturation rate was same across the groups. The quercetin supplementation significantly improved primordial and antral stage follicles. A greater number of apoptotic cells were observed in primary and antral follicles in the HS group. In conclusion, the quercetin provision improves the follicular development, minimize granulosa cells apoptosis, and maintain the oocyte competence in HS rabbits. Copyright © 2017. Published by Elsevier Inc.

Reproductive choices and outcomes after freezing oocytes for medical reasons: a follow-up study.

PubMed

Dahhan, T; Dancet, E A F; Miedema, D V; van der Veen, F; Goddijn, M

2014-09-01

What reproductive choices do women make after they have cryopreserved oocytes for medical reasons? Women who had cryopreserved oocytes for medical reasons and tried to become pregnant, either attempted natural conception or resorted to assisted reproduction with fresh oocytes. Women confronted with a risk of premature ovarian insufficiency, due to gonadotoxic therapy, ovarian surgery or genetic predisposition, have an indication to cryopreserve oocytes. Many of these women will retain ovarian function, thus will retain the possibility of natural conception. The added value of cryopreserved oocytes to reproductive outcomes is unknown as there is a lack of follow-up of women who have cryopreserved oocytes for medical reasons. This follow-up study included a cohort of 85 women who cryopreserved their oocytes for medical reasons between 2009 and 2012. Medical data from women who cryopreserved their oocytes at the Centre for Reproductive Medicine in the Academic Medical Centre in Amsterdam were extracted and self-report questionnaires were disseminated. The collected data considered demographics, outcomes of ovarian stimulation, fertility-threatening treatments, menstrual cycle changes, pregnancy attempts and outcomes and intended plans for the cryopreserved oocytes. A total of 68 women, followed up for an average 25.3 months, returned the questionnaire (response rate: 80%). None of the women had used her cryopreserved oocytes although 16 women had tried to conceive. Of these women, eight were trying to conceive naturally, five had conceived naturally within 2 months and three had conceived with assisted reproduction not requiring cryopreserved oocytes (two women with conventional IVF because of tubal pathology and endometriosis and one woman with IUI because of polycystic ovary syndrome). Three out of the eight pregnancies had resulted in live births, two resulted in miscarriages and three were ongoing. Most women (71%) intended to conceive with their cryopreserved oocytes as a last resource option. Transferability of our findings is challenged by the small sample but positively affected by our high response rate. As the time span between cryopreservation of oocytes and follow-up was short, follow-up of the cohort should be repeated in 2 years. After a mean follow-up of 2 years, none of the women with a medical reason to cryopreserve oocytes had used her oocytes. Women who were trying to conceive during follow-up were doing so without using their stored oocytes. It is unclear whether starting assisted reproduction while having cryopreserved oocytes is the most appropriate clinical decision. Our findings emphasize the relevance of taking the chances of natural conception into account in counselling women about cryopreservation of oocytes. This study was not externally funded. There are no conflicts of interest to declare. © The Author 2014. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Bovine non-competent oocytes (BCB-) negatively impact the capacity of competent (BCB+) oocytes to undergo in vitro maturation, fertilisation and embryonic development.

PubMed

Salviano, M B; Collares, F J F; Becker, B S; Rodrigues, B A; Rodrigues, J L

2016-04-01

Competent oocyte selection remains a bottleneck in the in vitro production (IVP) of mammalian embryos. Among the vital assays described for selecting competent oocytes for IVP, the brilliant cresyl blue (BCB) test has shown consistent results. The aim of the first experiment was to observe if oocytes directly submitted to IVM show similar cleavage and blastocyst rates as those obtained with oocytes maintained under the same in vitro conditions as the oocytes that undergo the BCB test. Bovine cumulus-oocyte complexes (COCs) were recovered from slaughterhouse-derived ovaries and, after morphological evaluation, were randomised grouped into three groups: (1) directly submitted to IVM; (2) oocytes submitted to the BCB test without the addition of BCB stain (BCB control group); and (3) submitted to the BCB test. The results showed that oocytes directly submitted to IVM reached similar cleavage (48/80 - 60%) and embryonic development rates to the blastocyst stage (10/48 - 21%) as the results obtained with the BCB control group oocytes (45/77 - 58% and 08/45 - 18%, respectively). The aim of the second experiment was to determine the cleavage and blastocyst rates obtained from BCB+ oocytes undergoing IVM in the presence of BCB- oocytes at a ratio of 10:1. COCs were recovered from slaughterhouse-derived ovaries and, after morphological evaluation, were randomised into two groups that were submitted to IVM either directly (1: control group) or submitted to the BCB test prior to IVM. After the BCB test, the COCs were classified as either BCB+ (blue cytoplasm) or BCB- (colourless cytoplasm) and then divided into four experimental groups: (2) BCB+; (3) BCB-; and (4) BCB+ matured in same IVM medium drop as (5) BCB- at a ratio of 10:1. After IVM (24 h), oocytes from the different experimental groups were submitted to in vitro fertilisation (IVF) and in vitro culture (IVC) under the same culture conditions until they reached the blastocyst stage (D7). With regards to the cleavage rate (48 h after IVF), only group 3 (102/229 - 44%) differed (P < 0.05) from the other groups [1 (145/241 - 60%); 2 (150/225 - 67%); 4 (201/318 - 63%) and 5 (21/33 - 63%)]. On day 7, the embryos from group 2 (BCB+) achieved the highest blastocyst rate (46/150 - 31%) (P < 0.05) when compared with the embryo development capacity of the other experimental groups (1: 31/145 - 21%; group 3: 17/102 - 17%; group 4: 46/201 - 23%; and group 5: 2/21 - 10%). In conclusion, submitting BCB+ oocytes that were separated from BCB- oocytes to IVM increases the rate of embryonic development to the blastocyst stage when compared to the control group, BCB- oocyte group, BCB+ paracrine group and BCB- paracrine group. The presence of non-competent oocytes during IVM, even in low proportion (1:10), reduces the capacity of competent oocytes to undergo embryo development and achieve blastocyst stage during IVC.

Dynamics of intracellular phospholipid membrane organization during oocyte maturation and successful vitrification of immature oocytes retrieved by ovum pick-up in cattle.

PubMed

Aono, Akira; Nagatomo, Hiroaki; Takuma, Tetsuya; Nonaka, Rika; Ono, Yoshitaka; Wada, Yasuhiko; Abe, Yasuyuki; Takahashi, Masashi; Watanabe, Tomomasa; Kawahara, Manabu

2013-05-01

The objective was to determine if immature bovine oocytes with cumulus cells at the germinal vesicle (GV) stage could be vitrified by aluminum sheets (AS; pieces of sheet-like aluminum foil). Cleavage rates in fertilized oocytes previously vitrified by the AS procedure were higher than those vitrified by a nylon-mesh holder (NM) procedure (89.3 ± 2.1% vs. 65.0 ± 3.7%). Cleaved embryos derived from the AS but not from the NM procedures developed to blastocysts. Furthermore, to investigate the effects of vitrifying GV oocytes on cytoplasmic structure and on the ability to undergo cytoplasmic changes, the intracellular phospholipid membrane (IM) was stained with the lipophilic fluorescent dye, 3,3'-dioctadecyloxa-carbocyanine perchlorate. After vitrification by AS, the IM remained intact relative to that of oocytes vitrified by NM. During in vitro maturation, reorganization of the IM was also undamaged in oocytes vitrified by AS before oocyte maturation, and the IM within oocytes vitrified by the NM procedure was evidently impaired. Finally, vitrification (AS) was used for GV oocytes collected using the ovum pick-up method. A bull calf was born after in vitro production and subsequent embryo transfer. The vitrification techniques described herein should facilitate generation of viable in vitro production bovine blastocysts using oocytes recovered using the ovum pick-up method. Copyright © 2013 Elsevier Inc. All rights reserved.

Holding equine oocytes in a commercial embryo-holding medium: New perspective on holding temperature and maturation time.

PubMed

Dini, Pouya; Bogado Pascottini, Osvaldo; Ducheyne, Kaatje; Hostens, Miel; Daels, Peter

2016-09-15

In the present study, we examined the effect of holding equine oocytes in Syngro embryo holding medium (EHM) overnight at either 4 °C, 17 °C, or 22 °C to 25 °C, on the time to maturation and developmental competence. We also examined the effect of placing denuded oocyte without extruded polar body back in maturation condition on subsequent maturation rate. In experiment 1, cumulus-oocyte complexes (COCs) were recovered postmortem and placed in EHM at 22 °C to 25 °C for 18 to 20 hours (OH) or placed directly in maturation (DM). The maturation rate was assessed after 22, 24, or 28 hours of culture. After denuding cumulus cells at 22 or 24 hours, oocytes without obvious polar body were placed back into culture and reassessed at subsequent time points. At 22 hours, a higher proportion of oocytes placed in OH achieved nuclear maturation than those placed in DM (63% and 37%, respectively, P = 0.008). At 24 and 28 hours, no significant differences in the % MII stage oocytes were observed between OH and DM. The nuclear maturation rate for OH oocytes was similar at 22, 24, and 28 hours, indicating that the maximum maturation rate was reached at an earlier time than that in DM. Oocytes fertilized by intracytoplasmic sperm injection resulted in a 7.1% and 6.3% blastocyst rate for OH and DM, respectively. Denuding oocytes after 22 hours or more of culture did not have an adverse effect on the final nuclear maturation rate. After 28 hours of culture, the same nuclear maturation rate (MII) was reached for nondenuded oocytes and oocytes denuded after 22 hours of 24 hours of culture. In experiment 2, COCs were held overnight at room temperature in EHM, then placed in maturation for 20, 22, and 28 hours. Nuclear maturation rate was significantly lower at 20 hours than 22 and 28 hours of culture and was similar at 22 and 28 hours, suggesting that at least 22 hours of culture is required to reach maximal maturation rate for stored oocytes (43%, 62%, and 65% at 20, 22, and 28 hours, respectively. P < 0.001). In experiment 3, COCs were either placed directly in culture or held at 22 °C to 25 °C, 17 °C, or 4 °C overnight. After 24 hours of culture, maturation rate was similar for all groups, suggesting that COCs can be stored in conventional 4 °C transport condition or 17 °C. In preliminary studies, COCs were held at 4 °C followed by 24 hours of culture, and mature oocytes were fertilized using intracytoplasmic sperm injection. Twenty-three injected oocytes yielded four blastocysts. In conclusion, we reported that oocytes can be placed in a commercial EHM and stored overnight without a detrimental effect on maturation rates or blastocyst development. Oocytes held in holding medium require less time to reach the MII stage than oocytes placed in culture directly. Removing the cumulus cells from oocytes that have been cultured for at least 22 hours does not seem to alter the final nuclear maturation rate. Finally, we observed no detrimental effect of storing oocytes at 4 °C for up to 18 hours, and oocytes appeared to maintain developmental competence and blastocyst potential. Copyright © 2016 Elsevier Inc. All rights reserved.

Short-term preservation of porcine oocytes in ambient temperature: novel approaches.

PubMed

Yang, Cai-Rong; Miao, De-Qiang; Zhang, Qing-Hua; Guo, Lei; Tong, Jing-Shan; Wei, Yanchang; Huang, Xin; Hou, Yi; Schatten, Heide; Liu, ZhongHua; Sun, Qing-Yuan

2010-12-07

The objective of this study was to evaluate the feasibility of preserving porcine oocytes without freezing. To optimize preservation conditions, porcine cumulus-oocyte complexes (COCs) were preserved in TCM-199, porcine follicular fluid (pFF) and FCS at different temperatures (4°C, 20°C, 25°C, 27.5°C, 30°C and 38.5°C) for 1 day, 2 days or 3 days. After preservation, oocyte morphology, germinal vesicle (GV) rate, actin cytoskeleton organization, cortical granule distribution, mitochondrial translocation and intracellular glutathione level were evaluated. Oocyte maturation was indicated by first polar body emission and spindle morphology after in vitro culture. Strikingly, when COCs were stored at 27.5°C for 3 days in pFF or FCS, more than 60% oocytes were still arrested at the GV stage and more than 50% oocytes matured into MII stages after culture. Almost 80% oocytes showed normal actin organization and cortical granule relocation to the cortex, and approximately 50% oocytes showed diffused mitochondria distribution patterns and normal spindle configurations. While stored in TCM-199, all these criteria decreased significantly. Glutathione (GSH) level in the pFF or FCS group was higher than in the TCM-199 group, but lower than in the non-preserved control group. The preserved oocytes could be fertilized and developed to blastocysts (about 10%) with normal cell number, which is clear evidence for their retaining the developmental potentiality after 3d preservation. Thus, we have developed a simple method for preserving immature pig oocytes at an ambient temperature for several days without evident damage of cytoplasm and keeping oocyte developmental competence.

A feasibility study of prepubertal and over mature aged local goat in relation to results of In Vitro growth culture to obtain additional M-II oocyte resources

NASA Astrophysics Data System (ADS)

Ciptadi, Gatot; Ihsan, M. Nur; Rahayu, Sri; Widjaja, D. H. K.; Mudawamah, Mudawamah

2017-11-01

The aims of this research are to study the potential source of mature (M-II) oocytes of domestic animals using follicles isolated from prepubertal and over mature aged Indonesian local goats, resulting from an in vitro growth (IVG) method. This method of IVG could provide a new source of M-II oocytes for embryo production. In Indonesia, a very limited number of a good quality oocytes are available for research purposes, as there is a limited number of reproductive females slaughtered, which is dominated by prepubertal and old mature aged animals. IVG culture systems could be improved as an alternative method to provide a new source of a good quality oocytes for in vitro maturation of M-II oocytes. From a number of prepubertal and mature aged goats slaughtered in a local abattoir, the small oocytes in the preantral follicles were cultured in vitro to normal oocyte growth. The methods used in this research are experimental. Follicles were isolated, cultured in vitro for 14 days individually using a sticky medium containing 4% (w/v) polyvinylpyrrolidone in TCM 199 10% Fetal Bovine Serum supplemented with Follicle Stimulating Hormone, which was then evaluated for their follicle development and oocyte quality. The research results showed that a minimum follicle size and oocyte diameter is needed (>100 um) for early evaluation of maturation to be achieved, meanwhile oocytes recovered from IVG after being cultured in vitro for maturation resulted in a very low rate of maturation. However, in the future, IVG of the preantral follicles of Indonesian local goat could be considered as an alternative source of oocytes for both research purposes and embryo production in vitro.

Cytoplasmic asters are required for progression past the first cell cycle in cloned mouse embryos.

PubMed

Miki, Hiromi; Inoue, Kimiko; Ogonuki, Narumi; Mochida, Keiji; Nagashima, Hiroshi; Baba, Tadashi; Ogura, Atsuo

2004-12-01

Unlike the oocytes of most other animal species, unfertilized murine oocytes contain cytoplasmic asters, which act as microtubule-organizing centers following fertilization. This study examined the role of asters during the first cell cycle of mouse nuclear transfer (NT) embryos. NT was performed by intracytoplasmic injection of cumulus cells. Cytoplasmic asters were localized by staining with an anti-alpha-tubulin antibody. Enucleation of MII oocytes caused no significant change in the number of cytoplasmic asters. The number of asters decreased after transfer of the donor nuclei into these enucleated oocytes, probably because some of the asters participated in the formation of the spindle that anchors the donor chromosomes. The cytoplasmic asters became undetectable within 2 h of oocyte activation, irrespective of the presence or absence of the donor chromosomes. After the standard NT protocol, a spindle-like structure persisted between the pseudopronuclei of these oocytes throughout the pronuclear stage. The asters reappeared shortly before the first mitosis and formed the mitotic spindle. When the donor nucleus was transferred into preactivated oocytes (delayed NT) that were devoid of free asters, the microtubules and microfilaments were distributed irregularly in the ooplasm and formed dense bundles within the cytoplasm. Thereafter, all of the delayed NT oocytes underwent fragmentation and arrested development. Treatment of these delayed NT oocytes with Taxol, which is a microtubule-assembling agent, resulted in the formation of several aster-like structures and reduced fragmentation. Some Taxol-treated oocytes completed the first cell cycle and developed further. This study demonstrates that cytoplasmic asters play a crucial role during the first cell cycle of murine NT embryos. Therefore, in mouse NT, the use of MII oocytes as recipients is essential, not only for chromatin reprogramming as previously reported, but also for normal cytoskeletal organization in reconstructed oocytes.

Regulation of germ cell development by intercellular signaling in the mammalian ovarian follicle.

PubMed

Clarke, Hugh J

2018-01-01

Prior to ovulation, the mammalian oocyte undergoes a process of differentiation within the ovarian follicle that confers on it the ability to give rise to an embryo. Differentiation comprises two phases-growth, during which the oocyte increases more than 100-fold in volume as it accumulates macromolecules and organelles that will sustain early embryogenesis; and meiotic maturation, during which the oocyte executes the first meiotic division and prepares for the second division. Entry of an oocyte into the growth phase appears to be triggered when the adjacent granulosa cells produce specific growth factors. As the oocyte grows, it elaborates a thick extracellular coat termed the zona pellucida. Nonetheless, cytoplasmic extensions of the adjacent granulosa cells, termed transzonal projections (TZPs), enable them to maintain contact-dependent communication with the oocyte. Through gap junctions located where the TZP tips meet the oocyte membrane, they provide the oocyte with products that sustain its metabolic activity and signals that regulate its differentiation. Conversely, the oocyte secretes diffusible growth factors that regulate proliferation and differentiation of the granulosa cells. Gap junction-permeable products of the granulosa cells prevent precocious initiation of meiotic maturation, and the gap junctions also enable oocyte maturation to begin in response to hormonal signals received by the granulosa cells. Development of the oocyte or the somatic compartment may also be regulated by extracellular vesicles newly identified in follicular fluid and at TZP tips, which could mediate intercellular transfer of macromolecules. Oocyte differentiation thus depends on continuous signaling interactions with the somatic cells of the follicle. WIREs Dev Biol 2018, 7:e294. doi: 10.1002/wdev.294 This article is categorized under: Gene Expression and Transcriptional Hierarchies > Cellular Differentiation Signaling Pathways > Cell Fate Signaling Early Embryonic Development > Gametogenesis. © 2017 Wiley Periodicals, Inc.

Effects of trehalose vitrification and artificial oocyte activation on the development competence of human immature oocytes.

PubMed

Zhang, Zhiguo; Wang, Tianjuan; Hao, Yan; Panhwar, Fazil; Chen, Zhongrong; Zou, Weiwei; Ji, Dongmei; Chen, Beili; Zhou, Ping; Zhao, Gang; Cao, Yunxia

2017-02-01

Sucrose and trehalose are conventional cryoprotectant additives for oocytes and embryos. Ethanol can artificially enhance activation of inseminated mature oocytes. This study aims to investigate whether artificial oocyte activation (AOA) with ethanol can promote the development competence of in vitro matured oocytes. A total of 810 human immature oocytes, obtained from 325 patients undergoing normal stimulated oocyte retrieval cycles, were in vitro maturated (IVM) either immediately after collection (Fresh group n = 291)) or after being vitrified as immature oocytes (Vitrified group n = 519). These groups were arbitrarily assigned. All fresh and vitrified oocytes which matured after a period of IVM then underwent intra-cytoplasmic sperm injection (ICSI). Half an hour following ICSI, they were either activated by 7% ethanol (AOA group) or left untreated (Non-AOA group). Fertilization, cleavage rate, blastocyst quality and aneuploidy rate were then evaluated. High-quality blastocysts were only obtained in both the fresh and vitrified groups which had undergone AOA after ICSI. Trehalose vitrification slightly, but not significantly, increased the formation rates of high-quality embryos (21.7% VS 15.4%, P > 0.05) and blastocysts (15.7% VS 7.69%, P > 0.05)) when compared with sucrose vitrification. Aneuploidy was observed in 12 of 24 (50%) of the AOA derived high quality blastocysts. High-quality blastocysts only developed from fresh or vitrified immature oocytes if the ICSI was followed by AOA. This information may be important for human immature oocytes commonly retrieved in normal stimulation cycles and may be particularly important for certain patient groups, such as cancer patients. AOA with an appropriate concentration of ethanol can enhance the developmental competence of embryos. Copyright © 2016 Elsevier Inc. All rights reserved.

Obesity-exposed oocytes accumulate and transmit damaged mitochondria due to an inability to activate mitophagy.

PubMed

Boudoures, Anna L; Saben, Jessica; Drury, Andrea; Scheaffer, Suzanne; Modi, Zeel; Zhang, Wendy; Moley, Kelle H

2017-06-01

Mitochondria are the most prominent organelle in the oocyte. Somatic cells maintain a healthy population of mitochondria by degrading damaged mitochondria via mitophagy, a specialized autophagy pathway. However, evidence from previous work investigating the more general macroautophagy pathway in oocytes suggests that mitophagy may not be active in the oocyte. This would leave the vast numbers of mitochondria - poised to be inherited by the offspring - vulnerable to damage. Here we test the hypothesis that inactive mitophagy in the oocyte underlies maternal transmission of dysfunctional mitochondria. To determine whether oocytes can complete mitophagy, we used either CCCP or AntimycinA to depolarize mitochondria and trigger mitophagy. After depolarization, we did not detect co-localization of mitochondria with autophagosomes and mitochondrial DNA copy number remained unchanged, indicating the non-functional mitochondrial population was not removed. To investigate the impact of an absence of mitophagy in oocytes with damaged mitochondria on offspring mitochondrial function, we utilized in vitro fertilization of high fat high sugar (HF/HS)-exposed oocytes, which have lower mitochondrial membrane potential and damaged mitochondria. Here, we demonstrate that blastocysts generated from HF/HS oocytes have decreased mitochondrial membrane potential, lower metabolites involved in ATP generation, and accumulation of PINK1, a mitophagy marker protein. This mitochondrial phenotype in the blastocyst mirrors the phenotype we show in HF/HS exposed oocytes. Taken together, these data suggest that the mechanisms governing oocyte mitophagy are fundamentally distinct from those governing somatic cell mitophagy and that the absence of mitophagy in the setting of HF/HS exposure contributes to the oocyte-to-blastocyst transmission of dysfunctional mitochondria. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Oocyte cryopreservation and in vitro culture affect calcium signalling during human fertilization.

PubMed

Nikiforaki, D; Vanden Meerschaut, F; Qian, C; De Croo, I; Lu, Y; Deroo, T; Van den Abbeel, E; Heindryckx, B; De Sutter, P

2014-01-01

What are the precise patterns of calcium oscillations during the fertilization of human oocytes matured either in vivo or in vitro or aged in vitro and what is the effect of cryopreservation? Human oocytes matured in vivo exhibit a specific pattern of calcium oscillations, which is affected by in vitro maturation, in vitro ageing and cryopreservation. Oscillations in cytoplasmic calcium concentration are crucial for oocyte activation and further embryonic development. While several studies have described in detail the calcium oscillation pattern during fertilization in animal models, studies with human oocytes are scarce. This was a laboratory-based study using human MII oocytes matured in vivo or in vitro either fresh or after cryopreservation with slow freezing or vitrification. Altogether, 205 human oocytes were included in the analysis. In vivo and in vitro matured human oocytes were used for this research either fresh or following vitrification/warming (V/W) and slow freezing/thawing (F/T). Human oocytes were obtained following written informed consent from patients undergoing ovarian hyperstimulation. For the calcium pattern analysis, oocytes were loaded with the ratiometric calcium indicator fluorescent dye Fura-2. Following ICSI using sperm from a single donor, intracellular calcium was measured for 16 h at 37°C under 6% CO(2). The calcium oscillation parameters were calculated for all intact oocytes that showed calcium oscillations and were analyzed using the Mann-Whitney U-test. Human in vivo MII oocytes display a specific pattern of calcium oscillations following ICSI. This pattern is significantly affected by in vitro ageing, with the calcium oscillations occurring over a longer period of time and with a lower frequency, shorter duration and higher amplitude (P < 0.05). In vitro matured oocytes from the GV and MI stage exhibit a different pattern of calcium oscillations with calcium transients being of lower frequency and shorter duration compared with in vivo matured MII. In MI oocytes that reached the MII stage within 3 h the calcium oscillations additionally appear over a longer period of time (P < 0.05). In vivo MII oocytes show a different calcium oscillation pattern following V/W with calcium oscillations occurring over a longer period of time, with a higher amplitude and a lower frequency (P < 0.05). In vitro matured oocytes, either from the GV or the MI stage, also display an altered pattern of calcium oscillations after V/W and the parameters that were similarly affected in all these oocyte groups are the frequency and the amplitude of the calcium transients. Slow freezing/thawing differentially affects the calcium oscillation pattern of in vitro matured and in vitro aged oocytes. The relationship between a specific pattern of calcium oscillations and subsequent human embryonic development could not be evaluated since the calcium indicator used and the high-intensity excitation light impair development. Furthermore, all oocytes were derived from stimulated cycles and immature oocytes were denuded prior to in vitro maturation. Our data show for the first time how calcium signalling during human fertilization is affected by oocyte in vitro maturation, in vitro ageing as well as V/W and slow freezing/thawing. The analysis of calcium oscillations could be used as an oocyte quality indicator to evaluate in vitro culture and cryopreservation techniques of human oocytes. This work was supported by a clinical research mandate from the Flemish Foundation of Scientific Research (FWO-Vlaanderen, FWO09/ASP/063) to F.V.M, a fundamental clinical research mandate from the FWO-Vlaanderen (FWO05/FKM/001) to P.D.S and a Ghent University grant (KAN-BOF E/01321/01) to B.H. The authors have no conflict of interest to declare.

Oocyte size, egg index, and body lipid content in relation to body size in the solitary bee Megachile rotundata.

PubMed

O'Neill, Kevin M; Delphia, Casey M; O'Neill, Ruth P

2014-01-01

Females of solitary, nest-provisioning bees have relatively low fecundity, but produce large eggs as part of their overall strategy of investing substantially in each offspring. In intraspecific comparisons of several species of solitary, nest-provisioning bees and wasps, the size of the mature eggs produced increases with female body size. We further examined oocyte size-body size correlations in the solitary bee Megachile rotundata (F.), an important crop pollinator. We hypothesized that larger females carry larger basal oocytes (i.e., those next in line to be oviposited) but that body size-oocyte size correlations would be absent soon after emergence, before their first eggs fully matured. Because egg production is likely affected by the quantity of stored lipids carried over from the bees' immature stages, we also tested the hypothesis that female body size is correlated with the body lipid content at adult emergence, the time during which oocyte growth accelerates. We found significant correlations of body size with oocyte size variables chosen to reflect: (1) the magnitude of the investment in the next egg to be laid (i.e., the length and volume of the basal oocyte) and (2) the longer term potential to produce mature oocytes (i.e., the summed lengths and volumes of the three largest oocytes in each female). Positive correlations existed throughout the nesting season, even during the first week following adult emergence. The ability to produce and carry larger oocytes may be linked to larger females starting the nesting season with greater lipid stores (which we document here) or to greater space within the abdomen of larger females. Compared to other species of solitary bees, M. rotundata appears to have (1) smaller oocytes than solitary nest-provisioning bees in general, (2) comparable oocyte sizes relative to congeners, and (3) larger oocytes than related brood parasitic megachilids.

Free cholesterol and cholesterol esters in bovine oocytes: Implications in survival and membrane raft organization after cryopreservation

PubMed Central

Ríos, Glenda L.; Canizo, Jesica R.; Antollini, Silvia S.; Alberio, Ricardo H.

2017-01-01

Part of the damage caused by cryopreservation of mammalian oocytes occurs at the plasma membrane. The addition of cholesterol to cell membranes as a strategy to make it more tolerant to cryopreservation has been little addressed in oocytes. In order to increase the survival of bovine oocytes after cryopreservation, we proposed not only to increase cholesterol level of oocyte membranes before vitrification but also to remove the added cholesterol after warming, thus recovering its original level. Results from our study showed that modulation of membrane cholesterol by methyl-β-cyclodextrin (MβCD) did not affect the apoptotic status of oocytes and improved viability after vitrification yielding levels of apoptosis closer to those of fresh oocytes. Fluorometric measurements based on an enzyme-coupled reaction that detects both free cholesterol (membrane) and cholesteryl esters (stored in lipid droplets), revealed that oocytes and cumulus cells present different levels of cholesterol depending on the seasonal period. Variations at membrane cholesterol level of oocytes were enough to account for the differences found in total cholesterol. Differences found in total cholesterol of cumulus cells were explained by the differences found in both the content of membrane cholesterol and of cholesterol esters. Cholesterol was incorporated into the oocyte plasma membrane as evidenced by comparative labeling of a fluorescent cholesterol. Oocytes and cumulus cells increased membrane cholesterol after incubation with MβCD/cholesterol and recovered their original level after cholesterol removal, regardless of the season. Finally, we evaluated the effect of vitrification on the putative raft molecule GM1. Cholesterol modulation also preserved membrane organization by maintaining ganglioside level at the plasma membrane. Results suggest a distinctive cholesterol metabolic status of cumulus-oocyte complexes (COCs) among seasons and a dynamic organizational structure of cholesterol homeostasis within the COC. Modulation of membrane cholesterol by MβCD improved survival of bovine oocytes and preserved integrity of GM1-related rafts after vitrification. PMID:28686720

Resveratrol reverses the adverse effects of a diet-induced obese murine model on oocyte quality and zona pellucida softening.

PubMed

Jia, Zhenzhen; Feng, Zeyang; Wang, Lining; Li, Hao; Wang, Hongyu; Xu, Dingqi; Zhao, Xin; Feng, Daofu; Feng, Xizeng

2018-05-23

Reproductive dysfunction associated with obesity is increasing among women of reproductive age, including infertility and increasing risk of miscarriage. In females, reproductive disorders are linked to declining quality of oocytes. Using a model of diet-induced obesity, we have investigated the possible effects of obesity on oocyte quality, including metabolism, lipid accumulation, ROS levels, meiosis and changes in spindle structure in Metaphase II. Our study showed that obesity induced by a high fat diet can impair oocyte meiosis, destroy spindle assembly, and promote oxidative stress and abnormal mitochondrial distribution. With the addition of resveratrol, the negative impact of diet-induced obesity on the quality of oocytes was alleviated to some extent. In addition, we found that obesity causes mouse oocytes to soften, and resveratrol can restore the zona pellucida of oocytes to the same state as the control group. In conclusion, resveratrol can reverse the adverse effects of obesity on oocytes, which is beneficial for subsequent embryonic development.

Femtosecond laser based enucleation of porcine oocytes for somatic cell nuclear transfer

NASA Astrophysics Data System (ADS)

Kütemeyer, K.; Lucas-Hahn, A.; Petersen, B.; Hassel, P.; Lemme, E.; Niemann, H.; Heisterkamp, A.

2009-07-01

Cloning of several mammalian species has been achieved by somatic cell nuclear transfer (SCNT) in recent years. However, this method still results in very low efficiencies around 1% which originate from suboptimal culture conditions and highly invasive techniques for oocyte enucleation and injection of the donor cell using micromanipulators. In this paper, we present a new minimal invasive method for oocyte imaging and enucleation based on the application of femtosecond (fs) laser pulses. After imaging of the oocyte with multiphoton microscopy, ultrashort pulses are focused onto the metaphase plate of MII-oocytes in order to ablate the DNA molecules. We show that fs laser based enucleation of porcine oocytes completely inhibits the first mitotic cleavage after parthenogenetic activation while maintaining intact oocyte morphology in most cases. In contrast, control groups without previous irradiation of the metaphase plate are able to develop to the blastocyst stage. Further experiments have to clarify the suitability of fs laser based enucleated oocytes for SCNT.

Zona-free oocyte fertilized with intracytoplasmic sperm injection and underwent further division: case report and literature review.

PubMed

Hsieh, Y Y; Chang, C C; Tsai, H D

2001-09-01

The zona pellucida (ZP) plays a protective role during fertilization and early embryonic development. It is related to sperm binding, the acrosome reaction, prevention of polyspermic fertilization, and holding blastomeres together before the morular stage. Zona-free oocytes are accidentally encountered. If these oocytes are healthy, they can be fertilized normally by intracytoplasmic sperm injection (ICSI). We reported on a couple with male infertility undergoing oocyte retrieval after ovarian hyperstimulation. Before the ICSI procedure, cumulus cells surrounding the oocytes were removed, which resulted in one oocyte escaping from its ZP. The zona-free oocyte was fertilized normally with ICSI and developed to the 8-cell stage. We observed that the zona-free zygote had the ability to further divide, despite its loose contact. The zona-free embryo was transferred with other zona-intact embryos, but the implantation failed. We conclude that zona-free oocytes can be rescued, fertilized with ICSI, and cultured for further transfer or cryopreservation.

Evolution of human oocyte cryopreservation: slow freezing versus vitrification.

PubMed

Levi-Setti, Paolo Emanuele; Patrizio, Pasquale; Scaravelli, Giulia

2016-12-01

The purpose is to determine the efficiency and efficacy of oocyte cryopreservation by slow freezing versus vitrification, recent data collected from the Italian National Assisted Reproductive Technology Register during the period 2009-2014 will be presented and reviewed. The data on oocyte cryopreservation were also compared with the results obtained with embryo cryopreservation and relative IVF with fresh oocytes. During the period 2009-2014 preservation of oocytes by vitrification had a significantly higher survival rate, implantation, and pregnancy rate than slow freezing; however, there are still large variations in success rates among centers in relation to the number of procedures performed. Vitrification has now become the method of choice for oocyte cryopreservation because of better results than slow freezing, but still requires a more standardized utilization. The transfer of fresh or cryopreserved embryo still shows a statistically significant better performance than transfers with embryos obtained with cryopreserved oocytes. Only in a few centers with much experience in cryopreservation are the results between transfers of frozen embryos or embryos obtained from oocyte cryopreservation comparable.

RNA SYNTHESIS IN THE MOUSE OOCYTE

PubMed Central

Moore, G. P. M.; Lintern-Moore, Sue; Peters, Hannah; Faber, M.

1974-01-01

RNA synthesis in the oocyte and granulosa cell nuclei of growing follicles has been studied in the mouse ovary. The RNA precursor [3H]uridine was administered intraperitoneally to adult mice and the amount of label incorporated into ovarian RNA was quantitated autoradiographically using grain-counting procedures. Uridine incorporation into the nucleus is low in oocytes of small, resting follicles but increases during follicle growth and reaches a peak prior to the beginning of antrum formation. Thereafter uptake rapidly declines and is very low in the oocytes of maturing follicles. Uridine incorporation into granulosa cell nuclei, in contrast to that found in the oocyte, increases gradually during most of the period of follicle growth. Qualitative studies of the activity of endogenous, DNA-dependent RNA polymerases have also been made in fixed oocytes isolated from follicles at different stages of growth. Polymerase activity is demonstrable in the nucleolus and nucleoplasm of oocytes from growing follicles, but is absent from maturing oocytes of large follicles. PMID:4813213

The Infertility of Repeat-Breeder Cows During Summer Is Associated with Decreased Mitochondrial DNA and Increased Expression of Mitochondrial and Apoptotic Genes in Oocytes.

PubMed

Ferreira, Roberta Machado; Chiaratti, Marcos Roberto; Macabelli, Carolina Habermann; Rodrigues, Carlos Alberto; Ferraz, Márcio Leão; Watanabe, Yeda Fumie; Smith, Lawrence Charles; Meirelles, Flávio Vieira; Baruselli, Pietro Sampaio

2016-03-01

Oocyte quality is known to be a major cause of infertility in repeat-breeder (RB) and heat-stressed dairy cows. However, the mechanisms by which RB oocytes become less capable of supporting embryo development remain largely unknown. Thus, the aim of this study was to investigate whether the decreased oocyte competence of RB cows (RBs) during summer is associated with an altered gene expression profile and a decrease in mitochondrial DNA (mtDNA) copy number. Therefore, oocytes collected from heifers, non-RBs in peak lactation (PLs), and RBs were used to evaluate mtDNA amounts as well as the expression levels of genes associated with the mitochondria (MT-CO1, NRF1, POLG, POLG2, PPARGC1A, and TFAM), apoptosis (BAX, BCL2, and ITM2B), and oocyte maturation (BMP15, FGF8, FGF10, FGF16, FGF17, and GDF9). The oocytes retrieved from RBs during winter contained over eight times more mtDNA than those retrieved from RBs during summer. They also contained significantly less mtDNA than oocytes retrieved from heifers and PLs during summer. Moreover, the expression of mitochondria- (NRF1, POLG, POLG2, PPARGC1A, and TFAM) and apoptosis-related (BAX and ITM2B) genes, as well as of GDF9, in RB oocytes collected during summer was significantly greater than that in oocytes collected from heifers and PLs during the same season. In oocytes from heifers and PLs, the expression levels of these genes were lower in those collected during summer compared with winter, but this difference was not observed in oocytes collected from RBs. Altogether, these data provide evidence of altered gene expression and reduced mtDNA copy number in the oocytes collected from RBs during summer. This indicates a loss of fertility in RBs during summer, which might be caused by a possible mitochondrial dysfunction associated with a greater chance of oocytes to undergo apoptosis. © 2016 by the Society for the Study of Reproduction, Inc.

Evaluation of zona pellucida birefringence intensity during in vitro maturation of oocytes from stimulated cycles.

PubMed

Petersen, Claudia G; Vagnini, Laura D; Mauri, Ana L; Massaro, Fabiana C; Silva, Liliane F I; Cavagna, Mario; Baruffi, Ricardo L R; Oliveira, Joao B A; Franco, José G

2011-04-23

This study evaluated whether there is a relationship between the zona pellucida birefringence (ZP-BF) intensity and the nuclear (NM) and cytoplasmic (CM) in vitro maturation of human oocytes from stimulated cycles. The ZP-BF was evaluated under an inverted microscope with a polarizing optical system and was scored as high/positive (when the ZP image presented a uniform and intense birefringence) or low/negative (when the image presented moderate and heterogeneous birefringence). CM was analyzed by evaluating the distribution of cortical granules (CGs) throughout the ooplasm by immunofluorescence staining. CM was classified as: complete, when CG was localized in the periphery; incomplete, when oocytes presented a cluster of CGs in the center; or in transition, when oocytes had both in clusters throughout cytoplasm and distributed in a layer in the cytoplasm periphery Nuclear maturation: From a total of 83 germinal vesicle (GV) stage oocytes, 58 of oocytes (69.9%) reached NM at the metaphase II stage. From these 58 oocytes matured in vitro, the high/positively scoring ZP-BF was presented in 82.7% of oocytes at the GV stage, in 75.8% of oocytes when at the metaphase I, and in 82.7% when oocytes reached MII. No relationship was observed between NM and ZP-BF positive/negative scores (P = 0.55). These variables had a low Pearson's correlation coefficient (r = 0.081). Cytoplasmic maturation: A total of 85 in vitro-matured MII oocytes were fixed for CM evaluation. Forty-nine oocytes of them (57.6%) showed the complete CM, 30 (61.2%) presented a high/positively scoring ZP-BF and 19 (38.8%) had a low/negatively scoring ZP-BF. From 36 oocytes (42.3%) with incomplete CM, 18 (50%) presented a high/positively scoring ZPBF and 18 (50%) had a low/negatively scoring ZP-BF. No relationship was observed between CM and ZP-BF positive/negative scores (P = 0.42). These variables had a low Pearson's correlation coefficient (r = 0.11). The current study demonstrated an absence of relationship between ZP-BF high/positive or low/negative score and nuclear and cytoplasmic in vitro maturation of oocytes from stimulation cycles.

Identification of oocyte progenitor cells in the zebrafish ovary.

PubMed

Draper, Bruce W

2012-01-01

Zebrafish breed year round and females are capable of producing thousands of eggs during their lifetime. This amazing fecundity is due to the fact that the adult ovary, contains premeiotic oocyte progenitor cells, called oogonia, which produce a continuous supply of new oocytes throughout adult life. Oocyte progenitor cells can be easily identified based on their expression of Vasa, and their characteristic nuclear morphology. Thus, the zebrafish ovary provides a unique and powerful system to study the genetic regulation of oocyte production in a vertebrate animal. A method is presented here for identifying oocyte progenitor cells in the zebrafish ovary using whole-mount confocal immunofluorescence that is simple and accurate.

Cytoskeleton and Cytoskeleton-Bound RNA Visualization in Frog and Insect Oocytes.

PubMed

Kloc, Malgorzata; Bilinski, Szczepan; Kubiak, Jacek Z

2016-01-01

The majority of oocyte functions involves and depends on the cytoskeletal elements, which include microtubules and actin and cytokeratin filaments. Various structures and molecules are temporarily or permanently bound to the cytoskeletal elements and their functions rely on cytoskeleton integrity and its timely assembly. Thus the accurate visualization of cytoskeleton is often crucial for studies and analyses of oocyte structure and functions. Here we describe several reliable methods for microtubule and/or microfilaments preservation and visualization in Xenopus oocyte extracts, and in situ in live and fixed insect and frog (Xenopus) oocytes. In addition, we describe visualization of cytoskeleton-bound RNAs using molecular beacons in live Xenopus oocytes.

Birth after 12 hours of oocyte refrigeration.

PubMed

Coban, Onder; Hacifazlioglu, Oguzhan; Ciray, H Nadir; Ulug, Ulun; Tekin, H Ibrahim; Bahceci, Mustafa

2010-12-01

To assess cycle outcome after oocyte refrigeration. Case report. Private IVF center. One couple in a donor oocyte program. Intracytoplasmic sperm injection and blastocyst culture after refrigeration of oocytes for 12 hours. Birth. Fourteen two-pronuclei zygotes from 17 metaphase II refrigerated oocytes resulted in transfer of two blastocysts at day 5 and cryopreservation of six excess embryos at day 6. The patient delivered one healthy male baby after 38 weeks' gestation. The successful outcome of oocyte refrigeration indicates that this protocol could be useful in circumstances in which a delay in obtaining spermatozoa arises. Copyright © 2010 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Ethical issues in paying for long-distance travel and accommodation expenses of oocyte donors.

PubMed

Heng, Boon Chin

2005-11-01

In many countries where the sale and purchase of donor oocytes is banned, a legal loophole often exploited is the use of free air tickets and hotel stay to entice prospective oocyte donors, in lieu of monetary payment. Such a means of procuring much-needed donor oocytes is ethically unsound. There is a lack of transparency and the personal motivation of the oocyte donor may be clouded by the desire for a 'free' holiday. Moreover, such a system is open to abuse by medical professionals. Private fertility clinics may source for oocyte donors to attract patients. The oocyte donor is paid nothing (except free travel and hotel stay), while the medical professional makes a handsome profit from treating infertile patients, which is not equitable. Medical professionals can also easily make a profit by marking up the price of air tickets and hotel stay to the patient (oocyte recipient). This would be thoroughly unprofessional, since the money earned is not directly related to the medical skills and expertise of the fertility specialist. Hence, it is imperative that various regulatory authorities should critically re-examine the giving of free travel and accommodation to oocyte donors, instead of monetary compensation.

On-chip enucleation of an oocyte by untethered microrobots

NASA Astrophysics Data System (ADS)

Ichikawa, Akihiko; Sakuma, Shinya; Sugita, Masakuni; Shoda, Tatsuro; Tamakoshi, Takahiro; Akagi, Satoshi; Arai, Fumihito

2014-09-01

We propose a novel on-chip enucleation of an oocyte with zona pellucida by using a combination of untethered microrobots. To achieve enucleation within the closed space of a microfluidic chip, two microrobots, a microknife and a microgripper were integrated into the microfluidic chip. These microrobots were actuated by an external magnetic force produced by permanent magnets placed on the robotic stage. The tip of the microknife was designed by considering the biological geometric feature of an oocyte, i.e. the oocyte has a polar body in maturation stage II. Moreover, the microknife was fabricated by using grayscale lithography, which allows fabrication of three-dimensional microstructures. The microgripper has a gripping function that is independent of the driving mechanism. On-chip enucleation was demonstrated, and the enucleated oocytes are spherical, indicating that the cell membrane of the oocytes remained intact. To confirm successful enucleation using this method, we investigated the viability of oocytes after enucleation. The results show that the production rate, i.e. the ratio between the number of oocytes that reach the blastocyst stage and the number of bovine oocytes after nucleus transfer, is 100%. The technique will contribute to complex cell manipulation such as cell surgery in lab-on-a-chip devices.

Effect of the timing of first cleavage on in vitro developmental potential of nuclear-transferred bovine oocytes receiving cumulus and fibroblast cells.

PubMed

Amarnath, Dasari; Kato, Yoko; Tsunoda, Yukio

2007-06-01

The aim of the present study was to examine whether cumulus and fibroblast cell nuclear-transferred oocytes, which have high and low potential to develop into normal calves, respectively, are different in terms of in their patterns of timing of first cleavage and in their relationships between timing of first cleavage and in vitro developmental potential. The timing of first cleavage was similar in both types of nuclear-transferred and in vitro fertilized oocytes. More than 86% of the oocytes cleaved within 24 h after activation or in vitro fertilization; these oocytes contributed to more than 98% of the total number of blastocysts in all three groups. The potential of oocytes that cleaved at different intervals to develop into blastocysts differed among the groups. The developmental potential of the cumulus cell nuclear-transferred oocytes and in vitro fertilized oocytes decreased with the increase in time required for cleavage. Fibroblast cell nuclear-transferred oocytes that cleaved at 20 h, an intermediate cleaving time, had higher potential to develop into blastocysts. The results of the present study suggest that the type of donor nucleus used for nuclear transfer affects the timing of first cleavage.

Loss of TIGAR induces oxidative stress and meiotic defects in oocytes from obese mice.

PubMed

Wang, Haichao; Cheng, Qing; Li, Xiaoyan; Hu, Feifei; Han, Longsen; Zhang, Hao; Li, Ling; Ge, Juan; Ying, Xiaoyan; Guo, Xuejiang; Wang, Qiang

2018-05-18

Maternal obesity has been reported to impair oocyte quality in mice, however, the underlying mechanisms remain unclear. In the present study, by conducting a comparative proteomic analysis, we identified a reduced expression of TIGAR protein in ovulated oocytes from high-fat diet (HFD)-fed mice. Specific depletion of TIGAR in mouse oocytes results in the marked elevation of reactive oxygen species (ROS) levels and the failure of meiotic apparatus assembly. Importantly, forced expression of TIGAR in HFD oocytes not only attenuates ROS production, but also partly prevents spindle disorganization and chromosome misalignment during meiosis. Meantime, we noted that TIGAR knockdown in oocytes induces a strong activation of autophagy, while overexpression of TIGAR significantly reduces the LC3 accumulation in HFD oocytes. By anti-oxidant treatment, we further demonstrated that such an autophagic response is dependent on the TIGAR-controlled ROS production. In summary, our data indicate a role for TIGAR in modulating redox homeostasis during oocyte maturation, and uncover that loss of TIGAR is a critical pathway mediating the effects of maternal obesity on oocyte quality. Published under license by The American Society for Biochemistry and Molecular Biology, Inc.

Effect of in-utero diethylstilboestrol exposure on human oocyte quality and fertilization in a programme of in-vitro fertilization.

PubMed

Kerjean, A; Poirot, C; Epelboin, S; Jouannet, P

1999-06-01

Genital tract abnormalities and adverse pregnancy outcome are well known in women exposed in utero to diethylstilboestrol (DES). Data about adverse reproductive performance in women exposed to DES have been published, including controversial reports of menstrual dysfunction, poor responses after ovarian stimulation, oocyte maturation and fertilization abnormalities. We compared oocyte quality, in-vitro fertilization results and embryo quality for women exposed in utero to DES with a control group. Between 1989 and 1996, 56 DES-exposed women who had 125 in-vitro fertilization (IVF) attempts were retrospectively compared to a control group of 45 women with tubal disease, who underwent 73 IVF attempts. Couples suffering from male infertility were excluded. The parameters compared were oocyte quality (maturation abnormalities, immature oocyte, mature oocyte), fertilization and cleavage rate (per treated and metaphase II oocytes), and embryo quality (number and grade). We found no significant difference in oocyte maturational status, fertilization rates, cleavage rates, embryo quality and development between DES-exposed subjects and control subjects. These results suggest that in-utero exposure to DES has no significant influence on oocyte quality and fertilization ability as judged during IVF attempts.

Evaluating methods of mouse euthanasia on the oocyte quality: cervical dislocation versus isoflurane inhalation.

PubMed

Roustan, Audrey; Perrin, Jeanne; Berthelot-Ricou, Anaïs; Lopez, Erica; Botta, Alain; Courbiere, Blandine

2012-04-01

Cervical dislocation is a commonly used method of mouse euthanasia. Euthanasia by isoflurane inhalation is an alternative method which allows the sacrifice of several mice at the same time with an anaesthesia, in the aim to decrease pain and animal distress. The objective of our study was to assess the impact of these two methods of euthanasia on the quality of mouse oocytes. By administering gonadotropins, we induced a superovulation in CD1 female mice. Mice were randomly assigned to euthanasia with cervical dislocation and isoflurane inhalation. Oviducts were collected and excised to retrieve metaphase II oocytes. After microscopic examination, oocytes were classified into three groups: intact, fragmented/cleaved and atretic. Intact metaphase II oocytes were employed for biomedical research. A total of 1442 oocytes in the cervical dislocation group were compared with 1230 oocytes in the isoflurane group. In the cervical dislocation group, 93.1% of the oocytes were intact, versus 65.8% in the isoflurane group (P ≤ 0.001). In light of these results, we conclude that cervical dislocation is the best method of mouse euthanasia for obtaining intact oocytes for biomedical research.

RNA-Seq transcriptome profiling of mouse oocytes after in vitro maturation and/or vitrification.

PubMed

Gao, Lei; Jia, Gongxue; Li, Ai; Ma, Haojia; Huang, Zhengyuan; Zhu, Shien; Hou, Yunpeng; Fu, Xiangwei

2017-10-16

In vitro maturation (IVM) and vitrification have been widely used to prepare oocytes before fertilization; however, potential effects of these procedures, such as expression profile changes, are poorly understood. In this study, mouse oocytes were divided into four groups and subjected to combinations of in vitro maturation and/or vitrification treatments. RNA-seq and in silico pathway analysis were used to identify differentially expressed genes (DEGs) that may be involved in oocyte viability after in vitro maturation and/or vitrification. Our results showed that 1) 69 genes were differentially expressed after IVM, 66 of which were up-regulated. Atp5e and Atp5o were enriched in the most significant gene ontology term "mitochondrial membrane part"; thus, these genes may be promising candidate biomarkers for oocyte viability after IVM. 2) The influence of vitrification on the transcriptome of oocytes was negligible, as no DEGs were found between vitrified and fresh oocytes. 3) The MII stage is more suitable for oocyte vitrification with respect to the transcriptome. This study provides a valuable new theoretical basis to further improve the efficiency of in vitro maturation and/or oocyte vitrification.

Quercetin improves the in vitro development of porcine oocytes by decreasing reactive oxygen species levels

PubMed Central

Kang, Jung-Taek; Kwon, Dae-Kee; Park, Sol-Ji; Kim, Su-Jin; Moon, Joon-Ho; Koo, Ok-Jae; Jang, Goo

2013-01-01

Quercetin is a plant-derived flavonoid found in fruits or vegetables that has antioxidant properties and acts as a free radical scavenger. We investigated the effects of quercetin on porcine oocyte nuclear maturation and embryonic development after parthenogenetic activation. We then evaluated the antioxidant activities of quercetin by measuring reactive oxygen species (ROS) levels in matured oocytes. Immature oocytes were untreated or treated with 1, 10, and 50 µg/mL quercetin during in vitro maturation (IVM). Quercetin treatment did not improve oocyte nuclear maturation, but significantly higher blastocyst rates (p < 0.05) of parthenogenetically activated oocytes were achieved when the IVM medium was supplemented with an adequate concentration of quercetin (1 µg/mL). However, cleavage rates and blastocyst cell numbers were not affected. Oocytes treated with 1 or 10 µg/mL quercetin had significantly lower (p < 0.05) levels of ROS than the control and group treated with the highest concentration of quercetin (50 µg/mL). Moreover, this highest concentration was detrimental to oocyte nuclear maturation and blastocyst formation. Based on our findings, we concluded that exogenous quercetin reduces ROS levels during oocyte maturation and is beneficial for subsequent embryo development. PMID:23388446

Successful ongoing pregnancies after vitrification of oocytes.

PubMed

Lucena, Elkin; Bernal, Diana Patricia; Lucena, Carolina; Rojas, Alejandro; Moran, Abby; Lucena, Andrés

2006-01-01

To demonstrate the efficiency of vitrifying mature human oocytes for different clinical indications. Descriptive case series. Cryobiology laboratory, Centro Colombiano de Fertilidad y Esterilidad-CECOLFES LTDA. (Bogotá, Colombia). Oocyte vitrification was offered as an alternative management for patients undergoing infertility treatment because of ovarian hyperstimulation syndrome, premature ovarian failure, natural ovarian failure, male factor, poor response, or oocyte donation. Mature oocytes were obtained from 33 donor women and 40 patients undergoing infertility treatment. Oocytes were retrieved by ultrasound-guided transvaginal aspiration and vitrified with the Cryotops method, with 30% ethylene glycol, 30% dimethyl sulfoxide, and 0.5 mol/L sucrose. Viability was assessed 3 hours after thawing. The surviving oocytes were inseminated by intracytoplasmic sperm injection. Fertilization was evaluated after 24 hours. The zygotes were further cultured in vitro for up to 72 hours until time of embryo transfer. Recovery, viability, fertilization, and pregnancy rates. Oocyte vitrification with the Cryotop method resulted in high rates of recovery, viability, fertilization, cleavage, and ongoing pregnancy. Vitrification with the Cryotop method is an efficient, fast, and economical method for oocyte cryopreservation that offers high rates of survival, fertilization, embryo development, and ongoing normal pregnancies, providing a new alternative for the management of female infertility.

Tetraspanins and Mouse Oocyte Microvilli Related to Fertilizing Ability.

PubMed

Benammar, Achraf; Ziyyat, Ahmed; Lefèvre, Brigitte; Wolf, Jean-Philippe

2017-07-01

Our electron microscopy observations demonstrate for the first time that the number of microvilli on the mice oocyte membrane decreases when meiosis progresses from prophase I to metaphase II (MII) stage, and the morphology of the microvilli also changes. Microvilli are significantly shorter and larger on the ovulated oocyte membrane than at the previous stages. Although clathrin vesicles clearly disappear during oocyte maturation, exosome-like vesicles begin to be secreted at the metaphase I stage, more strongly at the MII stage. Multivesicular bodies are visible only at the MII stage. Since several oocyte tetraspanins are involved in the gamete interaction, Cd9 being congregated on the MII oocyte microvilli, we analyzed the effect of tetraspanin deletion on oocyte membrane morphology. The Cd9 -/- and Cd9 -/- Cd81 -/- deletions are associated with a decreased microvilli density on the MII oocyte surface. Microvilli thickness is significantly increased whatever the deleted tetraspanin gene be. Only Cd9 deletion clearly disturbs the vesicular traffic, increasing the number of clathrin and exosome vesicles. Additional investigations are necessary to elucidate how tetraspanins modulate the microvilli morphology, likely in relation with cytoskeleton. The role of oocyte exosomes in gamete adhesion/fusion remains to be further studied.

Ultrastructure changes in buffalo (Bubalus bubalis) oocytes before and after maturation in vitro with sericin.

PubMed

Gustina, Sri; Hasbi, Hasbi; Karja, Ni Wayan Kurniani; Setiadi, Mohamad Agus; Supriatna, Iman

2017-12-01

The aim of this research was to identify the changes in the cytoplasmic ultrastructure of immature and matured oocytes in buffalo (Bubalus bubalis). Oocytes were matured in vitro in tissue culture medium-199 with and without sericin, and then analyzed by light and transmission electron microscopy. The experiment result showed that the nuclear maturation rate of buffalo oocytes was significantly higher in the presence of sericin (80.6%) than without sericin (68.1%) (P < 0.05). The immature oocytes were characterized by cortical granule clusters in the ooplasm and the absence of perivitelline space (PVS). In contrast, the oocytes matured either with or without sericin showed the formation of PVS, erected microvilli, the migration of cortical granules to the cytoplasmic periphery, and the clear appearance of the mitochondria and vesicle in the oolemma. Interestingly, matured oocytes with sericin have smaller cortical granules than do immature oocytes (P < 0.05). In conclusion, supplementation of 0.05% sericin in the maturation medium can enhance the maturation rate of buffalo oocytes. Several cytoplasmic ultrastructures were relocated and modulated during the in vitro maturation process of buffalo oocytes: PVS development, cortical granules migration to periphery, and mitochondria and vesicles in the cortical region. The ultrastructure was similar between the groups with and without sericin. © 2017 Japanese Society of Animal Science.

Increased incidence of preeclampsia in mothers of advanced age conceiving by oocyte donation.

PubMed

Dior, Uri P; Laufer, Neri; Chill, Henry H; Granovsky-Grisaru, Sorina; Yagel, Simcha; Yaffe, Haim; Gielchinsky, Yuval

2018-05-01

The aim of this study was to evaluate the risk of preeclampsia in women of advanced age who conceived through donated oocytes as compared with natural conceptions. A historical prospective study of singleton live births of parturients ≥ 45 years of age at four university hospitals was conducted. For the purpose of the study, the population was divided by the mode of conception into two groups: oocyte donation and natural conception. The main outcome variable in this study was preeclampsia. Secondary outcomes included pregnancy-induced hypertension and Small for Gestational Age. Two hundred and seventy pregnancies were achieved naturally and 135 women conceived by oocyte donation. Mean age at delivery for the natural conception and oocyte donation groups was 45.7 and 47.8, respectively. Preeclampsia complicated 3 out of 270 (1.1%) natural conception pregnancies and 17 out of 135 (12.6%) oocyte donation conceptions. After adjusting for confounders, oocyte donation pregnancies were found to be associated with a 12-fold increased risk for preeclampsia (P = 0.001). Among oocyte donation pregnancies, the risk of preeclampsia was not affected by parity or age. A substantially increased risk for preeclampsia was found in oocyte donation pregnancies, suggesting that the foreign oocyte may play a specific biologic role in the development of preeclampsia after the age of 45.

Live Birth from Slow-Frozen Rabbit Oocytes after In Vivo Fertilisation

PubMed Central

Jiménez-Trigos, Estrella; Vicente, José S.; Marco-Jiménez, Francisco

2013-01-01

In vivo fertilisation techniques such as intraoviductal oocyte transfer have been considered as alternatives to bypass the inadequacy of conventional in vitro fertilisation in rabbit. There is only one study in the literature, published in 1989, that reports live offspring from cryopreserved rabbit oocytes. The aim of the present study was to establish the in vivo fertilisation procedure to generate live offspring with frozen oocytes. First, the effect of two recipient models (i) ovariectomised or (ii) oviduct ligated immediately after transfer on the ability of fresh oocytes to fertilise were compared. Second, generation of live offspring from slow-frozen oocytes was carried out using the ligated oviduct recipient model. Throughout the experiment, recipients were artificially inseminated 9 hours prior to oocyte transfer. In the first experiment, two days after unilateral transfer of fresh oocytes, oviducts and uterine horns were flushed to assess embryo recovery rates. The embryo recovery rates were low compared to control in both ovariectomised and ligated oviduct groups. However, ligated oviduct recipient showed significantly (P<0.05) higher embryo recovery rates compared to ovariectomised and control-transferred. In the second experiment, using bilateral oviduct ligation model, all females that received slow-frozen oocytes became pregnant and delivered a total of 4 live young naturally. Thus, in vivo fertilisation is an effective technique to generate live offspring using slow-frozen oocytes in rabbits. PMID:24358281

The role of the PI3K-Akt signaling pathway in the developmental competence of bovine oocytes.

PubMed

Andrade, Gabriella Mamede; da Silveira, Juliano Coelho; Perrini, Claudia; Del Collado, Maite; Gebremedhn, Samuel; Tesfaye, Dawit; Meirelles, Flávio Vieira; Perecin, Felipe

2017-01-01

The ovarian follicle encloses oocytes in a microenvironment throughout their growth and acquisition of competence. Evidence suggests a dynamic interplay among follicular cells and oocytes, since they are constantly exchanging "messages". We dissected bovine ovarian follicles and recovered follicular cells (FCs-granulosa and cumulus cells) and cumulus-oocyte complexes (COCs) to investigate whether the PI3K-Akt signaling pathway impacted oocyte quality. Following follicle rupture, COCs were individually selected for in vitro cultures to track the follicular cells based on oocyte competence to reach the blastocyst stage after parthenogenetic activation. Levels of PI3K-Akt signaling pathway components in FCs correlated with oocyte competence. This pathway is upregulated in FCs from follicles with high-quality oocytes that are able to reach the blastocyst stage, as indicated by decreased levels of PTEN and increased levels of the PTEN regulators bta-miR-494 and bta-miR-20a. Using PI3K-Akt responsive genes, we showed decreased FOXO3a levels and BAX levels in lower quality groups, indicating changes in cell cycle progression, oxidative response and apoptosis. Based on these results, the measurement of levels of PI3K-Akt pathway components in FCs from ovarian follicles carrying oocytes with distinct developmental competences is a useful tool to identify putative molecular pathways involved in the acquisition of oocyte competence.

Effects of dimethyl sulfoxide on asymmetric division and cytokinesis in mouse oocytes.

PubMed

Zhou, Dongjie; Shen, Xinghui; Gu, Yanli; Zhang, Na; Li, Tong; Wu, Xi; Lei, Lei

2014-06-21

Dimethyl sulfoxide (DMSO) is used extensively as a permeable cryoprotectant and is a common solvent utilized for several water-insoluble substances. DMSO has various biological and pharmacological activities; however, the effect of DMSO on mouse oocyte meiotic maturation remains unknown. In DMSO-treated oocytes, we observed abnormal MII oocytes that contained large polar bodies, including 2-cell-like MII oocytes, during in vitro maturation. Oocyte polarization did not occur, due to the absence of actin cap formation and spindle migration. These features are among the primary causes of abnormal symmetric division; however, analysis of the mRNA expression levels of genes related to asymmetric division revealed no significant difference in the expression of these factors between the 3% DMSO-treated group and the control group. After each "blastomere" of the 2-cell-like MII stage oocytes was injected by one sperm head respectively, the oocytes still possessed the ability to extrude the second polar body from each "blastomere" and to begin cleavage. However, MII oocytes with large polar bodies developed to the blastocyst stage after intracytoplasmic sperm injection (ICSI). Furthermore, other permeable cryoprotectants, such as ethylene glycol and glycerol, also caused asymmetric division failure. Permeable cryoprotectants, such as DMSO, ethylene glycol, and glycerol, affect asymmetric division. DMSO disrupts cytokinesis completion by inhibiting cortical reorganization and polarization. Oocytes that undergo symmetric division maintain the ability to begin cleavage after ICSI.

AGE-SPECIFIC PROBABILITY OF LIVE-BIRTH WITH OOCYTE CRYOPRESERVATION: AN INDIVIDUAL PATIENT DATA META-ANALYSIS

PubMed Central

CIL, AYLIN PELIN; BANG, HEEJUNG; OKTAY, KUTLUK

2013-01-01

Objective To estimate age-specific probabilities of live-birth with oocyte cryopreservation in non-donor (ND) egg cycles. Design Individual patient data (IPD) meta-analysis. Setting Assisted reproduction centers. Patients Infertile patients undergoing ND mature oocyte cryopreservation. Interventions PubMed was searched for the clinical studies on oocyte cryopreservation from January 1996 through July 2011. Randomized and non-randomized studies that used ND frozen-thawed mature oocytes with pregnancy outcomes were included. Authors of eligible studies were contacted to obtain IPD. Main outcome measures Live-birth probabilities based on age, cryopreservation method, and the number of oocytes thawed, injected, or embryos transferred. Results Original data from 10 studies including 2265 cycles from 1805 patients were obtained. Live-birth success rates declined with age regardless of the freezing technique. Despite this age-induced compromise, live-births continued to occur as late as to the ages of 42 and 44 with slowly-frozen (SF) and vitrified (VF) oocytes, respectively. Estimated probabilities of live-birth for VF oocytes were higher than those for SF. Conclusions The live-birth probabilities we calculated would enable more accurate counseling and informed decision of infertile women who consider oocyte cryopreservation. Given the success probabilities, we suggest that policy-makers should consider oocyte freezing as an integral part of prevention and treatment of infertility. PMID:23706339

Embryological outcomes in cycles with human oocytes containing large tubular smooth endoplasmic reticulum clusters after conventional in vitro fertilization.

PubMed

Itoi, Fumiaki; Asano, Yukiko; Shimizu, Masashi; Honnma, Hiroyuki; Murata, Yasutaka

2016-01-01

There have been no studies analyzing the effect of large aggregates of tubular smooth endoplasmic reticulum (aSERT) after conventional in vitro fertilization (cIVF). The aim of this study was to investigate whether aSERT can be identified after cIVF and the association between the embryological outcomes of oocytes in cycles with aSERT. This is a retrospective study examining embryological data from cIVF cycles showing the presence of aSERT in oocytes 5-6 h after cIVF. To evaluate embryo quality, cIVF cycles with at least one aSERT-metaphase II (MII) oocyte observed (cycles with aSERT) were compared to cycles with normal-MII oocytes (control cycles). Among the 4098 MII oocytes observed in 579 cycles, aSERT was detected in 100 MII oocytes in 51 cycles (8.8%). The fertilization rate, the rate of embryo development on day 3 and day 5-6 did not significantly differ between cycles with aSERT and control group. However, aSERT-MII oocytes had lower rates for both blastocysts and good quality blastocysts (p < 0.05). aSERT can be detected in the cytoplasm by removing the cumulus cell 5 h after cIVF. However, aSERT-MII oocytes do not affect other normal-MII oocytes in cycles with aSERT.

Effect of Nanoparticles on the Survival and Development of Vitrified Porcine GV Oocytes.

PubMed

Li, W J; Zhou, X L; Liu, B L; Dai, J J; Song, P; Teng, Y

BACKGROUND: Some mammalian oocytes have been successfully cryopreserved by vitrification. However, the survival and developmental rate of vitrified oocytes is still low. The incorporation of nanoparticles into cryoprotectant (CPA) may improve the efficiency of vitrification by changing the properties of solutions. The toxicity of different concentrations of hydroxy apatite (HA), silica dioxide (SO 2 ), aluminum oxide (Al 2 O 3 ) and titanium dioxide (TiO 2 ) nanoparticles (20 nm in diameter) to oocytes was tested and the toxicity threshold value of each nanoparticle was determined. Porcine GV oocytes were vitrified in optimized nano-CPA, and effects of diameter and concentration of nanoparticles on the survival rate and developmental rate of porcine GV oocytes were compared. HA nanoparticles have demonstrated the least toxicity among four nanoparticles and the developmental rate of GV-stage porcine oocytes was 100% when its concentration was lower than 0.5%. By adding 0.1% HA into VS, the developmental rate of GV-stage porcine oocytes (22%) was significantly higher than other groups. The effect of vitrification in nano-CPA on oocytes was related to the concentration of HA nanoparticles rather than their size. By adding 0.05% HA nanoparticles (60nm in diameter), the developmental rate increased dramatically from 14.7% to 30.4%. Nano-cryopreservation offers a new way to improve the effect of survival and development of oocytes, but the limitation of this technology shall not be ignored.

N-hexane alters the maturation of oocytes and induces apoptosis in mice.

PubMed

Liu, Jin; Huang, Lei; Sun, Yan; Li, Yu Chen; Zhu, Jian Lin; Wang, Wen Xiang; Zhang, Wen Chang

2013-09-01

This study was aimed to determine the effects of n-hexane on the maturation of mouse oocytes. Cell culture was used to observe the maturation of mouse oocytes and CLSM was employed to determine their apoptosis. Germinal vesicle breakdown (GVBD) and extrusion of the first polar body in mouse oocytes were significantly inhibited by n-hexane. After fertilization, the number of eggs in the mouse was significantly reduced by n-hexane. Mitochondrial membrane potentials (ΔΨm) were altered in mouse oocytes that were leading to apoptosis of the oocytes. N-hexane might have affected the maturation of oocytes, causing alteration of ΔΨm and leading to apoptosis which maybe one of the most important mechanisms. Copyright © 2013 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

Transcriptome dynamics and molecular cross-talk between bovine oocyte and its companion cumulus cells

PubMed Central

2011-01-01

Background The bi-directional communication between the oocyte and its companion cumulus cells (CCs) is crucial for development and functions of both cell types. Transcripts that are exclusively expressed either in oocytes or CCs and molecular mechanisms affected due to removal of the communication axis between the two cell types is not investigated at a larger scale. The main objectives of this study were: 1. To identify transcripts exclusively expressed either in oocyte or CCs and 2. To identify those which are differentially expressed when the oocyte is cultured with or without its companion CCs and vice versa. Results We analyzed transcriptome profile of different oocyte and CC samples using Affymetrix GeneChip Bovine Genome array containing 23000 transcripts. Out of 13162 genes detected in germinal vesicle (GV) oocytes and their companion CCs, 1516 and 2727 are exclusively expressed in oocytes and CCs, respectively, while 8919 are expressed in both. Similarly, of 13602 genes detected in metaphase II (MII) oocytes and CCs, 1423 and 3100 are exclusively expressed in oocytes and CCs, respectively, while 9079 are expressed in both. A total of 265 transcripts are differentially expressed between oocytes cultured with (OO + CCs) and without (OO - CCs) CCs, of which 217 and 48 are over expressed in the former and the later groups, respectively. Similarly, 566 transcripts are differentially expressed when CCs mature with (CCs + OO) or without (CCs - OO) their enclosed oocytes. Of these, 320 and 246 are over expressed in CCs + OO and CCs - OO, respectively. While oocyte specific transcripts include those involved in transcription (IRF6, POU5F1, MYF5, MED18), translation (EIF2AK1, EIF4ENIF1) and CCs specific ones include those involved in carbohydrate metabolism (HYAL1, PFKL, PYGL, MPI), protein metabolic processes (IHH, APOA1, PLOD1), steroid biosynthetic process (APOA1, CYP11A1, HSD3B1, HSD3B7). Similarly, while transcripts over expressed in OO + CCs are involved in carbohydrate metabolism (ACO1, 2), molecular transport (GAPDH, GFPT1) and nucleic acid metabolism (CBS, NOS2), those over expressed in CCs + OO are involved in cellular growth and proliferation (FOS, GADD45A), cell cycle (HAS2, VEGFA), cellular development (AMD1, AURKA, DPP4) and gene expression (FOSB, TGFB2). Conclusion In conclusion, this study has generated large scale gene expression data from different oocyte and CCs samples that would provide insights into gene functions and interactions within and across different pathways that are involved in the maturation of bovine oocytes. Moreover, the presence or absence of oocyte and CC factors during bovine oocyte maturation can have a profound effect on transcript abundance of each cell types, thereby showing the prevailing molecular cross-talk between oocytes and their corresponding CCs. PMID:21261964

Oocyte developmental failure in response to elevated nonesterified fatty acid concentrations: mechanistic insights.

PubMed

Van Hoeck, V; Leroy, J L M R; Arias Alvarez, M; Rizos, D; Gutierrez-Adan, A; Schnorbusch, K; Bols, P E J; Leese, H J; Sturmey, R G

2013-01-01

Elevated plasma nonesterified fatty acid (NEFA) concentrations are associated with negative energy balance and metabolic disorders such as obesity and type II diabetes. Such increased plasma NEFA concentrations induce changes in the microenvironment of the ovarian follicle, which can compromise oocyte competence. Exposing oocytes to elevated NEFA concentrations during maturation affects the gene expression and phenotype of the subsequent embryo, notably prompting a disrupted oxidative metabolism. We hypothesized that these changes in the embryo are a consequence of modified energy metabolism in the oocyte. To investigate this, bovine cumulus oocyte complexes were matured under elevated NEFA conditions, and energy metabolism-related gene expression, mitochondrial function, and ultrastructure evaluated. It was found that expression of genes related to REDOX maintenance was modified in NEFA-exposed oocytes, cumulus cells, and resultant blastocysts. Moreover, the expression of genes related to fatty acid synthesis in embryos that developed from NEFA-exposed oocytes was upregulated. From a functional perspective, inhibition of fatty acid β-oxidation in maturing oocytes exposed to elevated NEFA concentrations restored developmental competence. There were no clear differences in mitochondrial morphology or oxygen consumption between treatments, although there was a trend for a higher mitochondrial membrane potential in zygotes derived from NEFA-exposed oocytes. These data show that the degree of mitochondrial fatty acid β-oxidation has a decisive impact on the development of NEFA-exposed oocytes. Furthermore, the gene expression data suggest that the resulting embryos adapt through altered metabolic strategies, which might explain the aberrant energy metabolism previously observed in these embryos originating from NEFA-exposed maturing oocytes.

Sericin Accelerates the Production of Hyaluronan and Decreases the Incidence of Polyspermy Fertilization in Bovine Oocytes During In Vitro Maturation

PubMed Central

HOSOE, Misa; YOSHIDA, Nao; HASHIYADA, Yutaka; TERAMOTO, Hidetoshi; TAKAHASHI, Toru; NIIMURA, Sueo

2014-01-01

Fetal bovine serum (FBS) has been widely used as a supplement in the maturation medium of bovine oocytes in vitro. However, serum contains many undefined factors and is potentially infectious to humans and animals. As a serum replacement, we evaluated the feasibility of using the silk protein, sericin, derived from the cocoons of silkworm. To examine the rates of oocyte maturation and fertilization, cumulus-oocyte complexes were cultured in TCM-199 supplemented with 0.01%, 0.05%, 0.1% or 0.15% sericin or 5% FBS. The sizes of the perivitelline space that might relate to polyspermy, the expressions of Has2 and CD44 mRNA, the amount of hyaluronan (hyaluronic acid: HA) contained in the oocytes and the rates of blastocyst formation following insemination were then compared between the oocytes cultured with 0.05% sericin and 5% FBS, because the polyspermy rates in oocytes cultured with 0.05% sericin were significantly lower than in those cultured with 5% FBS. After in vitro maturation (IVM), the mean size of the perivitelline space was significantly greater in oocytes cultured with sericin than in those cultured with FBS, although the rates of nuclear maturation, fertilization and blastocyst formation of oocytes under both IVM conditions were not significantly different. The expression of HAS2 and CD44 mRNA and the amount of HA in the denuded oocytes cultured with 0.05% sericin were significantly greater than in those cultured with FBS. These results indicate the feasibility of sericin as an alternative protein supplement for IVM in bovine oocytes. PMID:24748396

Sericin accelerates the production of hyaluronan and decreases the incidence of polyspermy fertilization in bovine oocytes during in vitro maturation.

PubMed

Hosoe, Misa; Yoshida, Nao; Hashiyada, Yutaka; Teramoto, Hidetoshi; Takahashi, Toru; Niimura, Sueo

2014-01-01

Fetal bovine serum (FBS) has been widely used as a supplement in the maturation medium of bovine oocytes in vitro. However, serum contains many undefined factors and is potentially infectious to humans and animals. As a serum replacement, we evaluated the feasibility of using the silk protein, sericin, derived from the cocoons of silkworm. To examine the rates of oocyte maturation and fertilization, cumulus-oocyte complexes were cultured in TCM-199 supplemented with 0.01%, 0.05%, 0.1% or 0.15% sericin or 5% FBS. The sizes of the perivitelline space that might relate to polyspermy, the expressions of Has2 and CD44 mRNA, the amount of hyaluronan (hyaluronic acid: HA) contained in the oocytes and the rates of blastocyst formation following insemination were then compared between the oocytes cultured with 0.05% sericin and 5% FBS, because the polyspermy rates in oocytes cultured with 0.05% sericin were significantly lower than in those cultured with 5% FBS. After in vitro maturation (IVM), the mean size of the perivitelline space was significantly greater in oocytes cultured with sericin than in those cultured with FBS, although the rates of nuclear maturation, fertilization and blastocyst formation of oocytes under both IVM conditions were not significantly different. The expression of HAS2 and CD44 mRNA and the amount of HA in the denuded oocytes cultured with 0.05% sericin were significantly greater than in those cultured with FBS. These results indicate the feasibility of sericin as an alternative protein supplement for IVM in bovine oocytes.

Fatty Acid Synthesis and Oxidation in Cumulus Cells Support Oocyte Maturation in Bovine

PubMed Central

Sanchez-Lazo, Laura; Brisard, Daphné; Elis, Sébastien; Maillard, Virginie; Uzbekov, Rustem; Labas, Valérie; Desmarchais, Alice; Papillier, Pascal; Monget, Philippe

2014-01-01

Oocyte meiotic maturation requires energy from various substrates including glucose, amino acids, and lipids. Mitochondrial fatty acid (FA) β-oxidation (FAO) in the oocyte is required for meiotic maturation, which is accompanied by differential expression of numerous genes involved in FAs metabolism in surrounding cumulus cells (CCs) in vivo. The objective was to elucidate components involved in FAs metabolism in CCs during oocyte maturation. Twenty-seven genes related to lipogenesis, lipolysis, FA transport, and FAO were chosen from comparative transcriptome analysis of bovine CCs before and after maturation in vivo. Using real-time PCR, 22 were significantly upregulated at different times of in vitro maturation (IVM) in relation to oocyte meiosis progression from germinal vesicle breakdown to metaphase-II. Proteins FA synthase, acetyl-coenzyme-A carboxylase, carnitine palmitoyltransferase, perilipin 2, and FA binding protein 3 were detected by Western blot and immunolocalized to CCs and oocyte cytoplasm, with FA binding protein 3 concentrated around oocyte chromatin. By mass spectrometry, CCs lipid profiling was shown to be different before and after IVM. FAO inhibitors etomoxir and mildronate dose-dependently decreased the oocyte maturation rate in vitro. In terms of viability, cumulus enclosed oocytes were more sensitive to etomoxir than denuded oocytes. In CCs, etomoxir (150μM) led to downregulation of lipogenesis genes and upregulated lipolysis and FAO genes. Moreover, the number of lipid droplets decreased, whereas several lipid species were more abundant compared with nontreated CCs after IVM. In conclusion, FAs metabolism in CCs is important to maintain metabolic homeostasis and may influence meiosis progression and survival of enclosed oocytes. PMID:25058602

Cows are not mice: the role of cyclic AMP, phosphodiesterases, and adenosine monophosphate-activated protein kinase in the maintenance of meiotic arrest in bovine oocytes.

PubMed

Bilodeau-Goeseels, Sylvie

2011-01-01

Meiotic maturation in mammalian oocytes is initiated during fetal development, and is then arrested at the dictyate stage - possibly for several years. Oocyte meiosis resumes in preovulatory follicles in response to the lutenizing hormone (LH) surge or spontaneously when competent oocytes are removed from follicles and cultured. The mechanisms involved in meiotic arrest and resumption in bovine oocytes are not fully understood, and several studies point to important differences between oocytes from rodent and livestock species. This paper reviews earlier and contemporary studies on the effects of cAMP-elevating agents and phosphodiesterase (PDE) enzyme inhibitors on the maintenance of meiotic arrest in bovine oocytes in vitro. Contrary to results obtained with mouse oocytes, bovine oocyte meiosis is inhibited by activators of the energy sensor adenosine monophosphate-activated protein kinase (AMPK, mammalian gene PRKA), which is activated by AMP, the degradation product of cAMP. It is not clear whether or not the effects were due to AMPK activation, and they may depend on culture conditions. Evidence suggests that other signaling pathways (for example, the cGMP/nitric oxide pathway) are involved in bovine oocyte meiotic arrest, but further studies are needed to understand the interactions between the signaling pathways that lead to maturation promoting factor (MPF) being inactive or active. An improved understanding of the mechanisms involved in the control of bovine oocyte meiosis will facilitate better control of the process in vitro, resulting in increased developmental competence and increased efficiency of in vitro embryo production procedures. Copyright © 2011 Wiley Periodicals, Inc.

In vitro fertilization of in vitro-matured equine oocytes: effect of maturation medium, duration of maturation, and sperm calcium ionophore treatment, and comparison with rates of fertilization in vivo after oviductal transfer.

PubMed

Hinrichs, K; Love, C C; Brinsko, S P; Choi, Y H; Varner, D D

2002-07-01

Three experiments were conducted to evaluate the effect of oocyte and sperm treatments on rates of in vitro fertilization (IVF) in the horse and to determine the capacity of in vitro-matured horse oocytes to be fertilized in vivo. There was no effect of duration of oocyte maturation (24 vs. 42 h) or calcium ionophore concentration during sperm capacitation (3 microM vs. 7.14 microM) on in vitro fertilization rates. Oocytes matured in 100% follicular fluid had significantly higher fertilization (13% to 24%) than did oocytes matured in maturation medium or in 20% follicular fluid (0% to 12%; P < 0.05). There was no significant difference in fertilization rate among 3 sperm treatments utilizing 7.14 microM calcium ionophore (12% to 21%). Of in vitro-matured oocytes recovered 40-44 h after transfer to the oviducts of inseminated mares, 77% showed normal fertilization (2 pronuclei to normal cleavage). Cleavage to 2 or more cells was seen in 22% of oocytes matured in follicular fluid and 63% of oocytes matured in maturation medium; this difference was significant (P < 0.05). We conclude that in vitro-matured horse oocytes are capable of being fertilized at high rates in the appropriate environment and that in vitro maturation of oocytes in follicular fluid increases fertilization rate in vitro but reduces embryo development after fertilization in vivo. Further work is needed to determine the optimum environment for sperm capacitation and IVF in the horse.

The development of oocytes in the ovary of a parthenogenetic tick, Haemaphysalis longicornis.

PubMed

Mihara, Ryo; Umemiya-Shirafuji, Rika; Abe, Yasuyuki; Matsuo, Tomohide; Horiuchi, Noriyuki; Kawano, Suguru; Fujisaki, Kozo; Suzuki, Hiroshi

2018-04-17

Haemaphysalis longicornis is an important vector of various pathogens in domestic animals and humans. The tick is a unique species with bisexual and parthenogenetic races. Although mating induces oocyte development, it is possible in the parthenogenetic race to complete oogenesis without copulation. Here we examined the developmental process of oocytes from unfed to the oviposition period in parthenogenetic H. longicornis. We classified the developmental stages of oocytes into five stages: stage I, germinal vesicle occupies more than half of the cytoplasm; stage II, germinal vesicle occupies less than half of the cytoplasm; stage III, germinal vesicle migrates from the center in the oocyte to the vicinity of the pedicel cells; stage IV, the cytoplasm is filled with yolk granules of various sizes; stage V, the cytoplasm is occupied by large yolk granules. Oocytes at the unfed period were undeveloped and classified as stage I. Stage I and II oocytes were observed at the rapid feeding period, indicating that oocyte development began after the initiation of blood feeding. All developmental stages of oocytes were observed at the pre-oviposition period. At 10 days after the beginning of the oviposition period, the ratios of stage I and II oocytes were higher than those of the previous period, suggesting that the ovarian development and activity may be continuing. Based on these findings, we propose classification criteria for the oocyte development in the parthenogenetic H. longicornis. The criteria will be useful for understanding the mechanisms of tick reproduction and transovarial transmission of pathogens. Copyright © 2018 Elsevier B.V. All rights reserved.

Obesity adversely impacts the number and maturity of oocytes in conventional IVF not in minimal stimulation IVF.

PubMed

Zhang, John J; Feret, Maciej; Chang, Lyndon; Yang, Mingxue; Merhi, Zaher

2015-05-01

The objective of this study was to assess the relationship between BMI and oocyte number and maturity in participants who underwent minimal stimulation (mini-) or conventional IVF. Participants who underwent their first autologous cycle of either conventional (n = 219) or mini-IVF (n = 220) were divided according to their BMI to analyze IVF outcome parameters. The main outcome measure was the number of oocytes in metaphase II (MII). Secondary outcomes included the number of total oocytes retrieved, fertilized (2PN) oocytes, cleavage and blastocyst stage embryos, clinical pregnancy (CP), and live birth (LB) rates. In conventional IVF, but not in mini-IVF, the number of total oocytes retrieved (14.5  ±  0.8 versus 8.8  ±  1.3) and MII oocytes (11.2 ± 0.7 versus 7.1 ± 1.1) were significantly lower in obese compared with normal BMI women. Multivariable linear regression adjusting for age, day 3 FSH, days of stimulation, and total gonadotropin dose demonstrated that BMI was an independent predictor of the number of MII oocytes in conventional IVF (p = 0.0004). Additionally, only in conventional IVF, BMI was negatively correlated with the total number of 2PN oocytes, as well as the number of cleavage stage embryos. Female adiposity might impair oocyte number and maturity in conventional IVF but not in mini-IVF. These data suggest that mild ovarian stimulation might yield healthier oocytes in obese women.

Lipids during Bufo arenarum oogenesis.

PubMed

Bruzzone, Ariana; Buschiazzo, Jorgelina; Alonso, Telma S

2003-05-01

The content and composition of phospholipids and triacylglycerols (TAGs) in Bufo arenarum oocytes in stages III and IV of their oogenesis were studied. The total amount of phospholipids in stage IV oocytes is 0.5-fold higher than in stage III oocytes. In both cases, the main phospholipids are phosphatidylcholine (PC) and phosphatidylethanolamine (PE). A striking observation concerns the high level of diphosphatidylglycerol (DPG) in stage III oocytes, which could be indicative of a relatively larger mitochondrial population with respect to other oogenetic stages. A net increase in sphingomyelin content was found during oogenesis. This fact could be related to the role of this phospholipid in the signal transductional pathways. In PC, palmitic (16:0), linoleic (18:2) and oleic (18:1) are the major fatty acids for both types of oocytes, while in PE the main acyl groups are 18:1, 16:0, arachidonic acid (20:4n6) and 18:2. PE is more unsaturated than PC and both phospholipids are more unsaturated in stage III oocytes than in stage IV oocytes. The amount of triacylglycerols is 0.3-fold higher in stage IV oocytes than in stage III oocytes. In both stages, the main fatty acids are 18:2, 18:1 and 16:0. During oogenesis, a significant increase in 18:1 and 18:3n3, and a decrease in 18:2 of TAG were found. The unsaturation index of TAGs from stage IV oocytes is higher than that from stage III oocytes. The TAG increase during oogenesis is consistent with the putative use of these lipids as a source of energy in embryo development.

Milrinone treatment of bovine oocytes during in vitro maturation benefits production of nuclear transfer embryos by improving enucleation rate and developmental competence.

PubMed

Naruse, Kenji; Iga, Kosuke; Shimizu, Manabu; Takenouchi, Naoki; Akagi, Satoshi; Somfai, Tamas; Hirao, Yuji

2012-01-01

In the production of cattle nuclear transfer embryos, the production efficiency is affected by the oocyte developmental competence and successful enucleation rate. This study investigated the effect of treating oocytes with milrinone, a phosphodiesterase inhibitor, on these two characteristics. When cumulus-oocyte complexes (COCs) were cultured for 19 h with 0, 50 or 100 μM of milrinone, the enucleation rate was significantly improved by 100 μM milrinone. However, milrinone treatment during in vitro maturation (IVM) also delayed meiotic progression by at least 2 h, which would affect the examination of enucleation rate and developmental competence of oocytes. Thus, in the second experiment, meiotic resumption was temporarily inhibited with butyrolactone I (BL-I; 100 μM, 18 h) to decrease the delayed maturation caused by milrinone; this enabled a more accurate comparison of the effects of milrinone after oocyte maturation. In nuclear transfer embryo production, oocytes treated with milrinone (100 μM, 20 h) showed a significantly higher rate of enucleation compared with that of control oocytes. This improved enucleation rate was associated with a closer location of the metaphase plate to the first polar body in the treated oocytes compared with that in control oocytes. Furthermore, milrinone improved the frequency of development to the blastocyst stage in the resulting embryos. In conclusion, milrinone supplementation during IVM improved enucleation rates by rendering the metaphase plate in close proximity to the first polar body, and this treatment also improved oocyte developmental competence. These benefits additively improved the yield of cloned embryos that developed to the blastocyst stage.

Ultrastructural characteristics of the follicle cell-oocyte interface in the oogenesis of Ceratophrys cranwelli.

PubMed

Villecco, Evelina I; Genta, Susana B; Sánchez Riera, Alicia N; Sánchez, Sara S

2002-05-01

In this work we carried out an ultrastructural analysis of the cell interface between oocyte and follicle cells during the oogenesis of the amphibian Ceratophrys cranwelli, which revealed a complex cell-cell interaction. In the early previtellogenic follicles, the plasma membrane of the follicle cells lies in close contact with the plasma membrane of the oocyte, with no interface between them. In the mid-previtellogenic follicles the follicle cells became more active and their cytoplasm has vesicles containing granular material. Their apical surface projects cytoplasmic processes (macrovilli) that contact the oocyte, forming gap junctions. The oocyte surface begins to develop microvilli. At the interface both processes delimit lacunae containing granular material. The oocyte surface has endocytic vesicles that incorporate this material, forming cortical vesicles that are peripherally arranged. In the late previtellogenic follicle the interface contains fibrillar material from which the vitelline envelope will originate. During the vitellogenic period, there is an increase in the number and length of the micro- and macrovilli, which become regularly arranged inside fibrillar tunnels. At this time the oocyte surface exhibits deep crypts where the macrovilli enter, thus increasing the follicle cell-oocyte junctions. In addition, the oocyte displays coated pits and vesicles evidencing an intense endocytic activity. At the interface of the fully grown oocyte the fibrillar network of the vitelline envelope can be seen. The compact zone contains a fibrillar electron-dense material that fills the spaces previously occupied by the now-retracted microvilli. The macrovilli are still in contact with the surface of the oocyte, forming gap junctions.

Spontaneous and LH-induced maturation in Bufo arenarum oocytes: importance of gap junctions.

PubMed

Toranzo, G Sánchez; Oterino, J; Zelarayán, L; Bonilla, F; Bühler, M I

2007-02-01

It has been demonstrated in Bufo arenarum that fully grown oocytes are capable of meiotic resumption in the absence of a hormonal stimulus if they are deprived of their follicular envelopes. This event, called spontaneous maturation, only takes place in oocytes collected during the reproductive period, which have a metabolically mature cytoplasm. In Bufo arenarum, progesterone acts on the oocyte surface and causes modifications in the activities of important enzymes, such as a decrease in the activity of adenylate cyclase (AC) and the activation of phospholipase C (PLC). PLC activation leads to the formation of diacylglycerol (DAG) and inositol triphosphate (IP(3)), second messengers that activate protein kinase C (PKC) and cause an increase in intracellular Ca(2+). Recent data obtained from Bufo arenarum show that progesterone-induced maturation causes significant modifications in the level and composition of neutral lipids and phospholipids of whole fully grown ovarian oocytes and of enriched fractions in the plasma membrane. In amphibians, the luteinizing hormone (LH) is responsible for meiosis resumption through the induction of progesterone production by follicular cells. The aim of this work was to study the importance of gap junctions in the spontaneous and LH-induced maturation in Bufo arenarum oocytes. During the reproductive period, Bufo arenarum oocytes are capable of undergoing spontaneous maturation in a similar way to mammalian oocytes while, during the non-reproductive period, they exhibit the behaviour that is characteristic of amphibian oocytes, requiring progesterone stimulation for meiotic resumption (incapable oocytes). This different ability to mature spontaneously is coincident with differences in the amount and composition of the phospholipids in the oocyte membranes. Capable oocytes exhibit in their membranes higher quantities of phospholipids than incapable oocytes, especially of PC and PI, which are precursors of second messengers such as DAG and IP(3). The uncoupling of the gap junctions with 1-octanol or halothane fails to induce maturation in follicles from the non-reproductive period, whose oocytes are incapable of maturing spontaneously. However, if the treatment is performed during the reproductive period, with oocytes capable of undergoing spontaneous maturation, meiosis resumption occurs in high percentages, similar to those obtained by manual defolliculation. Interestingly, results show that LH is capable of inducing GVBD in both incapable oocytes and in oocytes capable of maturing spontaneously as long as follicle cells are present, which would imply the need for a communication pathway between the oocyte and the follicle cells. This possibility was analysed by combining LH treatment with uncoupling agents such as 1-octanol or halothane. Results show that maturation induction with LH requires a cell-cell coupling, as the uncoupling of the gap junctions decreases GVBD percentages. Experiments with LH in the presence of heparin, BAPTA/AM and theophylline suggest that the hormone could induce GVBD by means of the passage of IP(3) or Ca(2+) through the gap junctions, which would increase the Ca(2+) level in the oocyte cytoplasm and activate phosphodiesterase (PDE), thus contributing to the decrease in cAMP levels and allowing meiosis resumption.

Oocyte mitochondrial deletions and heteroplasmy in a bovine model of ageing and ovarian stimulation.

PubMed

Hammond, Elizabeth R; Green, Mark P; Shelling, Andrew N; Berg, Martin C; Peek, John C; Cree, Lynsey M

2016-04-01

Maternal ageing and ovarian stimulation result in the accumulation of mitochondrial DNA (mtDNA) deletions and heteroplasmy in individual oocytes from a novel bovine model for human assisted reproductive technology (ART). The levels of mtDNA deletions detected in oocytes increased with ovarian ageing. Low levels of mtDNA heteroplasmy were apparent across oocytes and no relationship was identified with respect to ovarian ageing or ovarian stimulation. Oocyte quality decreases with ovarian ageing and it is postulated that the mtDNA may have a role in this decline. The impact of ovarian stimulation on oocyte quality is poorly understood. Human studies investigating these effects are often limited by the use of low quality oocytes and embryos, variation in age and ovarian stimulation regimens within the patients studied, as well as genetic and environmental variability. Further, no study has investigated mtDNA heteroplasmy in individual oocytes using next-generation sequencing (NGS), and little is known about whether the oocyte accumulates heteroplasmic mtDNA mutations following ageing or ovarian stimulation. A novel bovine model for the effect of stimulation and age in human ART was undertaken using cows generated by somatic cell nuclear transfer (SCNT) from one founder, to produce a homogeneous population with reduced genetic and environmental variability. Oocytes and somatic tissues were collected from young (3 years of age; n = 4 females) and old (10 years of age; n = 5 females) cow clones following multiple natural ovarian cycles, as well as oocytes following multiple mild (FSH only) and standard (based on human a long GnRH agonist protocol) ovarian stimulation cycles. In addition, oocytes were recovered in a natural cycle from naturally conceived cows aged 4-13.5 years (n = 10) to provide a heterogeneous cohort for mtDNA deletion studies. The presence or absence of mtDNA deletions were investigated using long-range PCR in individual oocytes (n = 62). To determine the detection threshold for mtDNA heteroplasmy levels in individual oocytes, a novel NGS methodology was validated; artificial mixtures of the Bos taurus and Bos indicus mitochondrial genome were generated at 1, 2, 5, 15 and 50% ratios to experimentally mimic different levels of heteroplasmy. This NGS methodology was then employed to determine mtDNA heteroplasmy levels in single oocytes (n = 24). Oocyte mtDNA deletion and heteroplasmy data were analysed by binary logistic regression with respect to the effects of ovarian ageing and ovarian stimulation regimens. Ovarian ageing, but not ovarian stimulation, increased the number of oocytes exhibiting mtDNA deletions (P = 0.04). A minimum mtDNA heteroplasmy level of 2% was validated as a sensitive (97-100%) threshold for variant detection in individual oocytes using NGS. Few mtDNA heteroplasmies were detected across the individual oocytes, with only 15 oocyte-specific variants confined to two of the 24 oocytes studied. There was no relationship (P > 0.05) evident between ovarian ageing or ovarian stimulation and the presence of mtDNA heteroplasmies. The low number of oocytes collected from the natural ovarian cycles limited the analysis. Fertilization and developmental potential of the oocytes was not assessed as the oocytes were destroyed for mtDNA deletion and heteroplasmy analysis. If the findings of this model apply to the human, this study suggests that the incidence of mtDNA deletions increases with age, but not with degree of ovarian stimulation, while the frequency of mtDNA heteroplasmies may be low regardless of ovarian ageing or level of ovarian stimulation. Funding was provided by Fertility Associates, the Nurture Foundation for Reproductive Research, the Fertility Society of Australia, and the Auckland Medical Research Foundation. J.C.P. is a shareholder of Fertility Associates and M.P.G. received a fellowship from Fertility Associates. The other authors of this manuscript declare no conflict of interest that could be perceived as prejudicing the impartiality of the reported research. © The Author 2016. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Distribution of alpha3, alpha5 and alpha(v) integrin subunits in mature and immature human oocytes.

PubMed

Capmany, G; Mart, M; Santaló, J; Bolton, V N

1998-10-01

The distribution of three integrin subunits, alpha3, alpha5 and alpha(v), in immature and mature human oocytes has been examined using immunofluorescence and confocal microscopy. The results demonstrate that both alpha5 and alpha(v) are present at the germinal vesicle stage, while alpha3 was only detected in oocytes after germinal vesicle breakdown, in metaphase I and II stage oocytes. The cortical concentration of integrin subunits alpha3 and alpha5 is consistent with their localization in the oolemma. In contrast, the homogeneous distribution of alpha(v) throughout the oocyte suggests the existence of cytoplasmic reservoirs of this protein in the oocyte.

[New possibilities resulting from oocyte banking].

PubMed

Revel, Ariel; Revel, Michel; Laufer, Neri; Kasher, Asa

2011-06-01

Oocyte cryopreservation solves the legal and ethical problems associated with the cryopreservation of embryos in patients undergoing in vitro fertilization procedures. Furthermore, it may also offer the possibility of extending the reproductive capability of young women with malignant diseases in cases where the treatment may compromise the ovarian reserve. Moreover, it may also offer alternatives for infertile patients who are subject to ovarian hyper-stimulation syndrome or premature ovarian faiLure or who require oocyte donation. The creation of banks for cryopreserved oocytes avoids the need for cycle synchronization or the formation of an over-supply of embryos destined for cryopreservation. If a Large number of oocytes is obtained it could possibly enable women and couples the opportunity to postpone childbirth according to their wishes. This paper reviews the revolution obtained by oocyte vitrification, reports on ethical issues and discusses the pros and cons of oocyte banking and its potential effects on society.

A PAR-1–dependent orientation gradient of dynamic microtubules directs posterior cargo transport in the Drosophila oocyte

PubMed Central

Parton, Richard M.; Hamilton, Russell S.; Ball, Graeme; Yang, Lei; Cullen, C. Fiona; Lu, Weiping; Ohkura, Hiroyuki

2011-01-01

Cytoskeletal organization is central to establishing cell polarity in various cellular contexts, including during messenger ribonucleic acid sorting in Drosophila melanogaster oocytes by microtubule (MT)-dependent molecular motors. However, MT organization and dynamics remain controversial in the oocyte. In this paper, we use rapid multichannel live-cell imaging with novel image analysis, tracking, and visualization tools to characterize MT polarity and dynamics while imaging posterior cargo transport. We found that all MTs in the oocyte were highly dynamic and were organized with a biased random polarity that increased toward the posterior. This organization originated through MT nucleation at the oocyte nucleus and cortex, except at the posterior end of the oocyte, where PAR-1 suppressed nucleation. Our findings explain the biased random posterior cargo movements in the oocyte that establish the germline and posterior. PMID:21746854

Ethics of medical and nonmedical oocyte cryopreservation.

PubMed

Patrizio, Pasquale; Molinari, Emanuela; Caplan, Arthur

2016-12-01

To assess the effectiveness and ethical dimensions of oocyte cryopreservation for both medical and social indications. As more women are postponing motherhood for a variety of reasons, including lack of partner, for completing career plans and reaching financial stability, they are resorting to oocyte cryopreservation. To make informed choices, women rely on their primary care physicians (PCPs) for initial advice, but PCPs are not always fully prepared to discuss oocyte cryopreservation. Interestingly, there are mixed feelings among obstetricians/gynecologists on whether oocyte cryopreservation should be used for elective reasons, whereas it is fully supported for medical indications. Oocyte vitrification has become an established procedure for safeguarding future reproductive chances for medical reasons, and its use is progressively expanding. There is an urgent need in preparing future PCPs and obstetricians/gynecologists as to how to initiate discussions with their patients about elective oocyte banking consistent with fully respecting patient autonomy so as to facilitate informed decisions.

Membrane currents in the oocyte of the toad Bufo arenarum.

PubMed

Kotsias, Basilio A; Damiano, Alicia E; Godoy, Sebastian; Assef, Yanina; Ibarra, Cristina; Cantiello, Horacio F

2002-03-01

The amphibian oocyte cell model is widely used for heterologous expression of ionic channels and receptors. Little is known, however, about the physiology of oocyte cell models other than Xenopus laevis. In this study, the two-electrode voltage clamp technique was used to assess the most common electrical patterns of oocytes of the South American toad Bufo arenarum. Basal membrane resistance, resting potential, and ionic currents were determined in this cell model. The oocyte transmembrane resistance was 0.35 M(Omega), and the resting potential in normal saline was about -33 mV with a range between -20 mV and -50 mV. This is, to our knowledge, the first attempt to begin an understanding of the ion transport mechanisms of Bufo arenarum oocytes. This cell model may provide a viable alternative to the expression of ion channels, in particular those endogenously observed in Xenopus laevis oocytes. Copyright 2002 Wiley-Liss, Inc.

A morphologic study of unfertilized oocytes and abnormal embryos in human in vitro fertilization.

PubMed

Bałakier, H; Casper, R F

1991-04-01

The morphology of human, unfertilized oocytes and abnormal embryos cultured in vitro for 48-72 hr was examined in an attempt to learn more about oocyte maturation and reproductive failure in in vitro fertilization (IVF). About 21% of the unfertilized oocytes were totally degenerated. The majority (56%) of the remaining oocytes was arrested at the metaphase II stage. They contained coherent chromosomal plates and had extruded the first polar body with nuclear material. About 13% of oocytes underwent spontaneous activation. In most of these cases the second polar body was retained and many subnuclei or one big nucleus was formed. Five percent of metaphase II oocytes penetrated by sperm were not activated, likely as a result of oocyte immaturity. The developmental ability of abnormal embryos was poor. Several one-cell-stage zygotes were arrested at the pronuclear stage or at mitosis of the first mitotic division. Polyspermic embryos, especially those which contained four or more pronuclei, did not divide or formed uneven, multinucleated blastomeres. However, some triploid and tetraploid embryos often appeared normal morphologically despite their lethal chromosomal abnormalities.

Cloning Mice.

PubMed

Ogura, Atsuo

2017-08-01

Viable and fertile mice can be generated by somatic nuclear transfer into enucleated oocytes, presumably because the transplanted somatic cell genome becomes reprogrammed by factors in the oocyte. The first somatic cloned offspring of mice were obtained by directly injecting donor nuclei into recipient enucleated oocytes. When this method is used (the so-called Honolulu method of somatic cell nuclear transfer [SCNT]), the donor nuclei readily and completely condense within the enucleated metaphase II-arrested oocytes, which contain high levels of M-phase-promoting factor (MPF). It is believed that the condensation of the donor chromosomes promotes complete reprogramming of the donor genome within the mouse oocytes. Another key to the success of mouse cloning is the use of blunt micropipettes attached to a piezo impact-driving micromanipulation device. This system saves a significant amount of time during the micromanipulation of oocytes and thus minimizes the loss of oocyte viability in vitro. For example, a group of 20 oocytes can be enucleated within 10 min by an experienced operator. This protocol is composed of seven parts: (1) preparing micropipettes, (2) setting up the enucleation and injection micropipettes, (3) collecting and enucleating oocytes, (4) preparing nucleus donor cells, (5) injecting donor nuclei, (6) activating embryos and culturing, and (7) transferring cloned embryos. © 2017 Cold Spring Harbor Laboratory Press.

Developmental consequences of cryopreservation of mammalian oocytes and embryos.

PubMed

Smith, Gary D; Silva E Silva, Cristine Ane

2004-08-01

During the last three decades, significant advances have been made in successful cryopreservation of mammalian preimplantation embryos, and more recently oocytes. The ability to cryopreserve, thaw, and establish pregnancies with supernumerary preimplantation embryos has become an important tool in fertility treatment. Human oocyte cryopreservation has practical application in preserving fertility for individuals at risk of compromised egg quality due to cancer treatments or advanced maternal age. While oocyte/embryo cryopreservation success has increased over time, there is still room for improvement. Oocytes and embryos are susceptible to cryo-damage, which collectively entails cellular damage caused by mechanical, chemical, or thermal forces during the freeze-thaw process. Basic studies focused on understanding cellular structures, their composition, and more importantly their functions, in normal cell developments will continue to be critical in assessing, understanding, and correcting oocyte/embryo cryo-damage. This review will delineate many of the oocyte/embryo intracellular and extracellular structures that are or may be compromised during cryopreservation. A global theme presented throughout this review is that many structural components of the oocyte/embryo also have essential functional roles in development. Compromising these cellular structures, and thus their cellular homeostatic functions, can deleteriously influence initial cryo-survival or compromise subsequent normal development through effects on the oocyte and/or early embryo.

Elective oocyte cryopreservation for deferred childbearing.

PubMed

Goldman, Kara N; Grifo, Jamie A

2016-12-01

Elective oocyte cryopreservation for deferred childbearing has gained popularity worldwide, commensurate with increased knowledge regarding age-related fertility decline. The purpose of this review is to summarize recent data regarding trends in delayed childbearing, review recent findings surrounding age-related fertility decline, acknowledge significant gaps in knowledge among patients and providers regarding fertility decline and review outcomes following elective oocyte cryopreservation. Despite an inevitable decline in fertility and increase in miscarriage with increasing female age, there is a growing worldwide trend to delay childbearing. Patients and providers alike demonstrate large gaps in knowledge surrounding age-related fertility decline. Oocyte cryopreservation is clinically approved for medically indicated fertility preservation, but a growing number of women are using oocyte cryopreservation to defer childbearing and maintain reproductive autonomy. Mounting data support the efficacy and safety of oocyte cryopreservation when used to electively defer childbearing, with recent studies demonstrating rates of euploidy, implantation and live birth rates equivalent to in-vitro fertilization (IVF) with fresh oocytes. Oocyte cryopreservation provides women with an option to defer childbearing and maintain reproductive autonomy, with IVF success rates on par with fresh IVF. However, it is critical that patients understand the limitations of oocyte cryopreservation. Greater education regarding age-related fertility decline should be geared toward patients and providers to prevent unintended childlessness.

Hanging drop monoculture for selection of optimal antioxidants during in vitro maturation of porcine oocytes.

PubMed

Ishikawa, S; Machida, R; Hiraga, K; Hiradate, Y; Suda, Y; Tanemura, K

2014-04-01

We analysed the effect of three antioxidants that have different functional mechanisms on the in vitro maturation (IVM) of porcine oocytes. Single oocyte monoculture using the hanging drop (HD) system has some advantages such as improving analysis efficiency brought by the smaller number of samples than the number of oocytes cultured in one drop. Direct effects of ligands on single oocytes could also be detected without considering the effects of paracrine factors from other oocytes. After 22 h of pre-culture, denuded oocytes were cultured for 22 h with 0.01 and 0.1 μg/ml of L-carnitine (LC), lactoferrin (LF) or sulforaphane (SF) in the presence/non-presence of oxidant stress induced by H2O2 supplementation to evaluate the reducing effects against oxidative stress on nuclear maturation. As a result, compared with LC and SF, LF showed effective reduction in oxidative stress at a lower concentration (0.01 μg/ml), suggesting that LF is a more effective antioxidant in porcine oocyte IVM. Additionally, LF also increased maturation rate even in culture without H2O2. Our results clearly suggest that the HD monoculture system is useful for screening the substances that affect porcine oocyte culture. © 2014 Blackwell Verlag GmbH.

Effects of tributyltin chloride on developing mouse oocytes and preimplantation embryos.

PubMed

Huang, Xian-Ju; Shen, Ming; Wang, Lizhong; Yu, Fengxiang; Wu, Wangjun; Liu, Hong-Lin

2015-04-01

Tributyltin, an organotin, is ubiquitous in estuaries and freshwater systems. Previous reports suggest that tributyltin is an endocrine disruptor in many wildlife species and it inhibits aromatase in mammalian placental and granulosa-like tumor cell lines. However, no evidence showing the effects of tributyltin on oocytes or preimplantation embryonic developmental competence exists. Therefore, we investigated the role of tributyltin chloride (TBTCl) in the development of female oocytes and preimplantation embryos. Briefly, female ICR mice were gavaged with 0 (vehicle), 4, and 8 mg/kg of TBTCl each day for 18 days. The fluorescence intensity analysis showed that the 5-methylcytosine level decreased after TBTCl treatment, indicating that the general DNA methylation level decreased in the treated oocytes. Our results demonstrate that TBTCl treatment results in decreased mRNA levels of imprinted genes H19, Igf2r, and Peg3 during oocyte growth. The TBTCl-treated oocytes showed a significant increase in reactive oxygen species levels in germinal vesicle oocytes. In TBTCl-treated oocytes, there was no difference in GPx and Sod1 expression, but a decreased mRNA level of Cat occurred when compared with control. Moreover, the blastocysts with TBTCl exposure displayed higher apoptotic signals. These results suggest that TBTCl induces developmental defects in oocytes and preimplantation embryos.

SKAP2 regulates Arp2/3 complex for actin-mediated asymmetric cytokinesis by interacting with WAVE2 in mouse oocytes.

PubMed

He, Shu-Wen; Xu, Bai-Hui; Liu, Yu; Wang, Ya-Long; Chen, Ming-Huang; Xu, Lin; Liao, Bao-Qiong; Lui, Rui; Li, Fei-Ping; Lin, Yan-Hong; Fu, Xian-Pei; Fu, Bin-Bin; Hong, Zi-Wei; Liu, Yu-Xin; Qi, Zhong-Quan; Wang, Hai-Long

2017-01-01

SKAP2 (Src kinase-associated phosphoprotein 2), a substrate of Src family kinases, has been suggested to be involved in actin-mediated cellular processes. However, little is known about its role in mouse oocyte maturation. In this study, we thus investigated the expression, localization, and functions of SKAP2 during mouse oocyte asymmetric division. SKAP2 protein expression was detected at all developmental stages in mouse oocytes. Immunofluorescent staining showed that SKAP2 was mainly distributed at the cortex of the oocytes during maturation. Treatment with cytochalasin B in oocytes confirmed that SKAP2 was co-localized with actin. Depletion of SKAP2 by injection with specific short interfering RNA caused failure of spindle migration, polar body extrusion, and cytokinesis defects. Meanwhile, the staining of actin filaments at the oocyte membrane and in the cytoplasm was significantly reduced after these treatments. SKAP2 depletion also disrupted actin cap and cortical granule-free domain formation, and arrested a large proportion of oocytes at the telophase stage. Moreover, Arp2/3 complex and WAVE2 expression was decreased after the depletion of SKAP2 activity. Our results indicate that SKAP2 regulates the Arp2/3 complex and is essential for actin-mediated asymmetric cytokinesis by interacting with WAVE2 in mouse oocytes.

Partial Recovery of Mitochondrial Function of Vitrified Porcine MII Stage Oocytes During Post-Thaw Incubation.

PubMed

Dai, J J; Yang, J H; Zhang, S S; Niu, Y F; Chen, Y N; Wu, C F; Zhang, D F

　　The survival of porcine oocytes is still very low after cryopreservation. To investigate whether and when the mitochondrial function of vitrified porcine oocytes could be recovered post-thaw. Mitochondrial potential, ROS level, ATP content, apoptotic rate, caspase activity, and parthenogenetics developmental ability of thawed porcine oocytes were measured after culture in vitro for 0, 1, 2 or 4 h. Mitochondrial potential after 2 h and 4 h post-thaw culture were 1.19 and 1.26, significantly lower than that of fresh oocytes but much higher than the groups cultured for 0 h and 1 h (P<0.05). Cryopreservation increased the ROS level in oocytes considerably, which decreased only after 2 to 4 h incubation following thaw. ATP content increased gradually over time and recovered to the level comparable to that of fresh oocytes after 4 h. Pan caspase levels increased after cryopreservation and reached the highest level at 1 h incubation. Thereafter it decreased to a low value, but still higher than fresh oocytes. Oocytes showing an early apoptotic event decreased upon 2 to 4 h incubation. The parthenogenetic cleavage and blastocyst rates were the highest (19.8% and 5.6%) after 2 h incubation. The recovery of mitochondrial function could complete after 2 to 4 h post-thaw incubation. Post-thaw incubation for 2 to 4 h reduced apoptotic events and improved parthenogenetic developmental ability of vitrified porcine MII stage oocytes.

Direct real-time measurement of intra-oocyte nitric oxide concentration in vivo.

PubMed

Goud, Pravin T; Goud, Anuradha P; Najafi, Tohid; Gonik, Bernard; Diamond, Michael P; Saed, Ghassan M; Zhang, Xueji; Abu-Soud, Husam M

2014-01-01

Nitric oxide (NO) is reported to play significant a role in oocyte activation and maturation, implantation, and early embryonic development. Previously we have shown that NO forms an important component of the oocyte microenvironment, and functions effectively to delay oocyte aging. Thus, precise information about intra-oocyte NO concentrations [NO] will result in designing more accurate treatment plans in assisted reproduction. In this work, the direct, real-time and quantitative intra-oocyte [NO] was measured utilizing an L-shaped amperometric integrated NO-selective electrode. This method not only provides an elegant and convenient approach to real-time the measurement of NO in physiological environments, but also mimics the loss of NO caused by rapid NO diffusion combined with its reactivity in the biological milieu. This experiment suggests that the NO levels of oocytes obtained from young animals are significantly higher than those of oocytes obtained from old animals. Additionally the NO levels stay constant during the measurements; however, the intra-oocyte [NO] is reduced significantly (70-75% reduction) in response to L-NAME incubation, suggesting that NO measurements are truly NOS based rather than caused by an unknown interfering substance in our system. We believe this first demonstration of the direct quantitative measurement of [NO] in situ in an intact cellular complex should be useful in tracking real-time and rapid changes at nanomolar levels. Moreover, this finding confirms and extends our previous work showing that supplementation with NO delays the oocyte aging process.

Direct Real-Time Measurement of Intra-Oocyte Nitric Oxide Concentration In Vivo

PubMed Central

Goud, Pravin T.; Goud, Anuradha P.; Najafi, Tohid; Gonik, Bernard; Diamond, Michael P.; Saed, Ghassan M.; Zhang, Xueji; Abu-Soud, Husam M.

2014-01-01

Nitric oxide (NO) is reported to play significant a role in oocyte activation and maturation, implantation, and early embryonic development. Previously we have shown that NO forms an important component of the oocyte microenvironment, and functions effectively to delay oocyte aging. Thus, precise information about intra-oocyte NO concentrations [NO] will result in designing more accurate treatment plans in assisted reproduction. In this work, the direct, real-time and quantitative intra-oocyte [NO] was measured utilizing an L-shaped amperometric integrated NO-selective electrode. This method not only provides an elegant and convenient approach to real-time the measurement of NO in physiological environments, but also mimics the loss of NO caused by rapid NO diffusion combined with its reactivity in the biological milieu. This experiment suggests that the NO levels of oocytes obtained from young animals are significantly higher than those of oocytes obtained from old animals. Additionally the NO levels stay constant during the measurements; however, the intra-oocyte [NO] is reduced significantly (70–75% reduction) in response to L-NAME incubation, suggesting that NO measurements are truly NOS based rather than caused by an unknown interfering substance in our system. We believe this first demonstration of the direct quantitative measurement of [NO] in situ in an intact cellular complex should be useful in tracking real-time and rapid changes at nanomolar levels. Moreover, this finding confirms and extends our previous work showing that supplementation with NO delays the oocyte aging process. PMID:24887331

Comparison of two different dosage of GnRH agonist as ovulation trigger in oocyte donors: a randomized controled trial.

PubMed

Zarcos, Sonia Morales; Mejía, Pamela Valdivieso; Stefani, Carla Donado; Martin, Pascual Sánchez; Martin, Fernando Sánchez

2017-09-01

To compare the results obtained with two different GnRH agonist dosages: 0.3mg versus 0.4mg to trigger ovulation in oocyte donor cycles. Experimental controlled randomized trial including 40 patients from a private practice center. The patients were randomized into two groups. Group A received a single dose of Triptorelin 0.3mg (Decapeptyl®) 36hours before pick-up. Group B patients received Triptorelin 0.4mg (Decapeptyl®) before pick-up to final oocyte maturation. We evaluated the total number of oocytes collected, the number of mature oocytes and total days of ovarian stimulation. The average of total collected oocytes were 16 (Group A) versus 15 (Group B), and the mean number of mature oocytes were 13 versus 12 respectively. The only variable showing a difference was the percentage of mature oocytes, which was greater in Group A, resulting in 84.6%, in contrast with those treated with 0.4mg of Triptorelin (78.6%), although these differences were not statistical significant (p=0.35). Days of stimulation did not differ between groups. No cases of empty follicle syndrome were reported. We found that an increase from 0.3 to 0.4mg of triptorelin in an oocyte donation program might not improve outcomes. Nevertheless, more studies might be necessary, not only in oocyte donors but in sterile women as well, to evaluate how GnRH agonist dosage could affect the results among other factors.

Dimethyl Sulfoxide Perturbs Cell Cycle Progression and Spindle Organization in Porcine Meiotic Oocytes

PubMed Central

Li, Xuan; Wang, Yan-Kui; Song, Zhi-Qiang; Du, Zhi-Qiang; Yang, Cai-Xia

2016-01-01

Meiotic maturation of mammalian oocytes is a precisely orchestrated and complex process. Dimethyl sulfoxide (DMSO), a widely used solvent, drug, and cryoprotectant, is capable of disturbing asymmetric cytokinesis of oocyte meiosis in mice. However, in pigs, DMSO’s effect on oocyte meiosis still remains unknown. We aimed to evaluate if DMSO treatment will affect porcine oocyte meiosis and the underlying molecular changes as well. Interestingly, we did not observe the formation of the large first polar body and symmetric division for porcine oocytes treated with DMSO, contrary to findings reported in mice. 3% DMSO treatment could inhibit cumulus expansion, increase nuclear abnormality, disturb spindle organization, decrease reactive oxygen species level, and elevate mitochondrial membrane potential of porcine oocytes. There was no effect on germinal vesicle breakdown rate regardless of DMSO concentration. 3% DMSO treatment did not affect expression of genes involved in spindle organization (Bub1 and Mad2) and apoptosis (NF-κB, Pten, Bcl2, Caspase3 and Caspase9), however, it significantly decreased expression levels of pluripotency genes (Oct4, Sox2 and Lin28) in mature oocytes. Therefore, we demonstrated that disturbed cumulus expansion, chromosome alignment, spindle organization and pluripotency gene expression could be responsible for DMSO-induced porcine oocyte meiotic arrest and the lower capacity of subsequent embryo development. Our results provide new insights on DMSO’s effect on porcine oocyte meiosis and raise safety concerns over DMSO’s usage on female reproduction in both farm animals and humans. PMID:27348312

Dimethyl Sulfoxide Perturbs Cell Cycle Progression and Spindle Organization in Porcine Meiotic Oocytes.

PubMed

Li, Xuan; Wang, Yan-Kui; Song, Zhi-Qiang; Du, Zhi-Qiang; Yang, Cai-Xia

2016-01-01

Meiotic maturation of mammalian oocytes is a precisely orchestrated and complex process. Dimethyl sulfoxide (DMSO), a widely used solvent, drug, and cryoprotectant, is capable of disturbing asymmetric cytokinesis of oocyte meiosis in mice. However, in pigs, DMSO's effect on oocyte meiosis still remains unknown. We aimed to evaluate if DMSO treatment will affect porcine oocyte meiosis and the underlying molecular changes as well. Interestingly, we did not observe the formation of the large first polar body and symmetric division for porcine oocytes treated with DMSO, contrary to findings reported in mice. 3% DMSO treatment could inhibit cumulus expansion, increase nuclear abnormality, disturb spindle organization, decrease reactive oxygen species level, and elevate mitochondrial membrane potential of porcine oocytes. There was no effect on germinal vesicle breakdown rate regardless of DMSO concentration. 3% DMSO treatment did not affect expression of genes involved in spindle organization (Bub1 and Mad2) and apoptosis (NF-κB, Pten, Bcl2, Caspase3 and Caspase9), however, it significantly decreased expression levels of pluripotency genes (Oct4, Sox2 and Lin28) in mature oocytes. Therefore, we demonstrated that disturbed cumulus expansion, chromosome alignment, spindle organization and pluripotency gene expression could be responsible for DMSO-induced porcine oocyte meiotic arrest and the lower capacity of subsequent embryo development. Our results provide new insights on DMSO's effect on porcine oocyte meiosis and raise safety concerns over DMSO's usage on female reproduction in both farm animals and humans.

Effects of dimethyl sulfoxide on asymmetric division and cytokinesis in mouse oocytes

PubMed Central

2014-01-01

Background Dimethyl sulfoxide (DMSO) is used extensively as a permeable cryoprotectant and is a common solvent utilized for several water-insoluble substances. DMSO has various biological and pharmacological activities; however, the effect of DMSO on mouse oocyte meiotic maturation remains unknown. Results In DMSO-treated oocytes, we observed abnormal MII oocytes that contained large polar bodies, including 2-cell–like MII oocytes, during in vitro maturation. Oocyte polarization did not occur, due to the absence of actin cap formation and spindle migration. These features are among the primary causes of abnormal symmetric division; however, analysis of the mRNA expression levels of genes related to asymmetric division revealed no significant difference in the expression of these factors between the 3% DMSO-treated group and the control group. After each “blastomere” of the 2-cell–like MII stage oocytes was injected by one sperm head respectively, the oocytes still possessed the ability to extrude the second polar body from each “blastomere” and to begin cleavage. However, MII oocytes with large polar bodies developed to the blastocyst stage after intracytoplasmic sperm injection (ICSI). Furthermore, other permeable cryoprotectants, such as ethylene glycol and glycerol, also caused asymmetric division failure. Conclusion Permeable cryoprotectants, such as DMSO, ethylene glycol, and glycerol, affect asymmetric division. DMSO disrupts cytokinesis completion by inhibiting cortical reorganization and polarization. Oocytes that undergo symmetric division maintain the ability to begin cleavage after ICSI. PMID:24953160

Goat oocyte quality and competence to undergo IVM and embryo development after parthenogenetic activation from goats fed with different levels of cashew nut bran as source of dietary lipids.

PubMed

Fernandes, C C L; Feltrin, C; Martins, L T; Gaudêncio Neto, S; Aguiar, L H; Silva, A M; Oliveira, C H A; Silva, L M; Silva, C M G; Bertolini, M; Rondina, D

2014-07-15

Lipid-rich and energy-dense diets can have significant effects on the reproductive physiology, including the ovarian function and fertility. The aim of this study was to assess the effect of cashew nut bran supplementation as a lipid source on follicle development, plasma and intrafollicular concentrations of cholesterol, and developmental competence of in vitro-matured goat oocytes. The inclusion of cashew nut bran as 24% of the goats' diet for 28 days increased the percentage and number of degenerated oocytes compared with the control (P < 0.05), and also the plasma cholesterol levels and the proportion of grade IV oocytes compared with all other treatments (P < 0.05). Moreover, a significant reduction was observed in the proportion of viable oocytes compared with the control and in the percentage of grade II oocytes compared with all other treatments (P < 0.05). Oocyte maturation, cleavage, and blastocyst rates after parthenogenetic activation of viable oocytes were not affected by the type of diet. In conclusion, the inclusion of cashew nut bran as 24% of the diet of adult goats for 28 days changed plasma cholesterol levels and reduced the proportion of viable immature oocytes; however, the 12% and 24% diet supplementations with cashew nut bran did not interfere with competence of resulting viable oocytes to reach the metaphase II stage after IVM, and to develop after parthenogenetic activation. Copyright © 2014 Elsevier Inc. All rights reserved.

Bisphenol A alters oocyte maturation by prematurely closing gap junctions in the cumulus cell-oocyte complex.

PubMed

Acuña-Hernández, Deyanira Guadalupe; Arreola-Mendoza, Laura; Santacruz-Márquez, Ramsés; García-Zepeda, Sihomara Patricia; Parra-Forero, Lyda Yuliana; Olivares-Reyes, Jesús Alberto; Hernández-Ochoa, Isabel

2018-04-01

In ovarian follicles, cumulus cells communicate with the oocyte through gap junction intercellular communication (GJIC), to nurture the oocyte and control its meiosis arrest and division. Bisphenol A (BPA) is a monomer found in polycarbonate-made containers that can induce functional alterations, including impaired oocyte meiotic division and reduced molecule transfer in GJIC. However, how BPA alters oocyte meiotic division is unclear. We investigated whether BPA effects on oocyte meiotic division were correlated with reduced transfer in GJIC. Cumulus cell-oocyte complexes (COCs) isolated from mouse preovulatory follicles were cultured with 0, 0.22, 2.2, 22, 220, and 2200 nM BPA for 2 h. An additional 16-h incubation with epidermal growth factor (EGF) was performed to promote the occurrence of meiotic resumption and progression to metaphase II. Without EGF stimulus, BPA treatment increased the percentage of oocytes undergoing meiotic resumption, decreased GJIC in the COCs, and did not modify GJIC gene (Cx43 and Cx37) and protein (CX43) expression. Following EGF stimulus, BPA increased the percentage of oocytes that remained at the anaphase and telophase stages, and decreased the percentage of oocytes reaching the metaphase II stage. Concomitantly, BPA reduced the expansion of cumulus cells. Carbenoxolone (a GJIC inhibitor) and 6-diazo-5-oxo-l-norleucine (a cumulus cell-expansion inhibitor) exerted effects on meiotic division similar to those exerted by BPA. These data suggest that BPA accelerates meiotic progression, leading to impaired prophase I-to-metaphase II transition, and that this adverse effect is correlated with reduced bidirectional communication in the COC. Copyright © 2018 Elsevier Inc. All rights reserved.

Impact of prolonged oocyte incubation time before vitrification on oocyte survival, embryo formation, and embryo quality in mice.

PubMed

Karami, Azade; Bakhtiari, Mitra; Azadbakht, Mehri; Ghorbani, Rostam; Khazaei, Mozafar; Rezaei, Mansour

2017-06-01

Oocyte incubation time before freezing is one of the factors affecting oocyte vitrification. In the assisted reproductive technology (ART) clinics, it is sometimes decided to perform oocyte vitrification after a long period of incubation time due to various conditions, such as inability to collect semen samples, unsuccessful urological interventions (PESA, TESE, etc.), or unexpected conditions. A time factor of up to 6 h has been studied in the available reports. Therefore, this study was designed to evaluate oocyte incubation time before freezing at 0, 6, 12, 18, and 24 h after retrieval. Metaphase II (MII) oocytes were obtained from NMRI female mice after being randomly divided into the five groups of 0, 6, 12, 18, and 24 h of freezing via hormonal stimulation following retrieval and entered into the vitrification-warming process. The thawed oocytes were evaluated according to the survival criteria and then inseminated with the sperms of male mice for in vitro fertilization. The next day, the embryo formation rate and embryo quality were assessed. Our results demonstrated that even after 24 h of incubation, the survival rate of oocytes was 51.35% with the embryo formation rate of 73.21%. However, the survival and embryo formation rates significantly decreased within 12, 18, and 24 h after retrieval compared to the groups vitrified at 0 h. The embryo quality was significantly reduced by vitrification at 0 to 24 h after retrieval. According to our data, although a prolonged incubation time before freezing reduced the survival rate, there was still a chance for oocytes to stay alive with acceptable embryo formation and quality rates after vitrification warming of oocytes.

Patterns of intracellular calcium oscillations in horse oocytes fertilized by intracytoplasmic sperm injection: possible explanations for the low success of this assisted reproduction technique in the horse.

PubMed

Bedford, Sylvia J; Kurokawa, Manabu; Hinrichs, Katrin; Fissore, Rafael A

2004-04-01

In all species studied, fertilization induces intracellular Ca2+ ([Ca2+]i) oscillations required for oocyte activation and embryonic development. This species-specific pattern has not been studied in the equine, partly due to the difficulties linked to in vitro fertilization in this species. Therefore, the objective of this study was to use intracytoplasmic sperm injection (ICSI) to investigate fertilization-induced [Ca2+]i signaling and, possibly, ascertain problems linked to the success of this technology in the horse. In vivo- and in vitro-matured mare oocytes were injected with a single motile stallion sperm. Few oocytes displayed [Ca2+]i responses regardless of oocyte source and we hypothesized that this may result from insufficient release of the sperm-borne active molecule (sperm factor) into the oocyte. However, permeabilization of sperm membranes with Triton-X or by sonication did not alleviate the deficient [Ca2+]i responses in mare oocytes. Thus, we hypothesized that a step downstream of release, possibly required for sperm factor function, is not appropriately accomplished in horse oocytes. To test this, ICSI-fertilized horse oocytes were fused to unfertilized mouse oocytes, which are known to respond with [Ca2+]i oscillations to injection of stallion sperm, and [Ca2+]i monitoring was performed. Such pairs consistently displayed [Ca2+]i responses demonstrating that the sperm factor is appropriately released into the ooplasm of horse oocytes, but that these are unable to activate and/or provide the appropriate substrate that is required for the sperm factor delivered by ICSI to initiate oscillations. These findings may have implications to improve the success of ICSI in the equine and other livestock species.

Equine sperm-oocyte interaction: results after intraoviductal and intrauterine inseminations of recipients for oocyte transfer.

PubMed

Carnevale, E M; Maclellan, L J; Coutinho da Silva, M A; Checura, C M; Scoggin, C F; Squires, E L

2001-12-03

Insemination of recipients for oocyte transfer and gamete intrafallopian transfer (GIFT) in five experiments were reviewed, and factors that affected pregnancy rates were ascertained. Oocytes were transferred into recipients that were (1) cyclic and ovulated at the approximate time of oocyte transfer, (2) cyclic with aspiration of the preovulatory follicle, and (3) noncyclic and treated with hormones. Recipients were inseminated before, after, or before and after transfer. Intrauterine and intraoviductal inseminations were done. Pregnancy rates were not different between cyclic and noncyclic recipients (8/15, 53% and 37/93, 39%). The highest numerical pregnancy rates resulted when recipients were inseminated with fresh semen from fertile stallions before oocyte transfer or inseminated with cooled transported semen before and after oocyte transfer. Oxytocin was administered to recipients before oocyte transfer when fluid was imaged within the uterus. Administration of oxytocin to recipients at the time of oocyte transfer resulted in significantly higher pregnancy rates than when oxytocin was not administered (17/26, 65% and 28/86, 33%). Intraoviductal and intrauterine inseminations of recipients during oocyte transfer resulted in similar embryo development rates when fresh semen was used (12/22, 55% and 14/26, 55%). However, embryo development rates significantly reduced when frozen (1/21, 5%) versus fresh sperm were inseminated into the oviduct. Results suggest that insemination of a recipient before and after transfer could be beneficial when semen quality is not optimal; however, a single insemination before transfer was adequate when fresh semen from fertile stallions was used. Absence of a preovulatory follicle did not appear to affect pregnancy rates in the present experiments. The transfer of sperm and oocytes (GIFT) into the oviduct was successful and repeatable as an assisted reproductive technique in the equine.

Vitrification: an effective new approach to oocyte banking and preserving fertility in cancer patients.

PubMed

Cobo, A; Domingo, J; Pérez, S; Crespo, J; Remohí, J; Pellicer, A

2008-05-01

Oocyte cryopreservation is a useful tool for preserving the fertility of cancer patients at risk of losing ovarian function due to undergoing potentially sterilising therapies. Results obtained with different cryopreservation protocols have been disappointing, particularly those obtained with slow cooling procedures. The efficacy of vitrification as an application in clinical practice has recently been demonstrated. The aim of this study is to report results obtained with the Cryotop method of oocyte vitrification in a population of healthy women and to point out its potential usefulness for fertility preservation in oncological patients. The study population consisting of non-oncological patients included 47 oocyte donors and 57 recipients undergoing an oocyte donation cycle of assisted reproductive technology (ART). A total of 693 mature metaphase II oocytes were collected following ovarian stimulation using long protocol down-regulation plus gonadotropin administration. Vitrification was carried out by means of the Cryotop method. Oocytes were donated to a compatible recipient after endometrial preparation. Of the 693 oocytes, 666 (96.1%) survived. A total of 487 (73.1%) were fertilised successfully. One hundred and seventeen embryos were transferred to 57 recipients. Pregnancy rate per transfer and implantation rates were 63.2% and 38.5% respectively. Twenty-eight healthy babies were later born. Oocyte cryo-banking by means of the Cryotop vitrification method represents a viable option for healthy women, producing excellent survival rates and a clinical outcome similar to that obtained with fresh oocytes. This approach could potentially be used in cancer patients who want to safeguard their fertility. Cancer patients could potentially benefit from this approach by storing their oocytes before the onset of the oncological therapy.

Developmental capacity of in vitro-matured human oocytes retrieved from polycystic ovary syndrome ovaries containing no follicles larger than 6 mm.

PubMed

Guzman, Luis; Ortega-Hrepich, Carolina; Albuz, Firas K; Verheyen, Greta; Devroey, Paul; Smitz, Johan; De Vos, Michel

2012-08-01

To test the developmental competence of oocytes in a nonhCG-triggered in vitro maturation (IVM) system when oocyte-cumulus complexes (OCC) are retrieved from antral follicles with a diameter of <6 mm. Prospective cohort study. Tertiary university-based referral center. From January 2010 to September 2011, 121 patients with polycystic ovaries/polycystic ovary syndrome underwent 239 IVM cycles in total. In 58 of these cycles (44 patients), all antral follicles had a diameter of <6 mm on the day of oocyte retrieval. NonhCG-triggered IVM of oocytes, fresh or vitrified/warmed embryo transfer (ET). Oocyte diameter, maturation rate, fertilization rate, embryo development and morphology, implantation rate, clinical pregnancy rate, ongoing pregnancy rate. Oocyte retrieval yielded 16.7 OCC/cycle, and 50.8% of oocytes completed IVM. The mean oocyte diameter increased from 108.8 ± 4.3 μm to 111.9 ± 4.1 μm after IVM. Mean fertilization rate was 63.7%, and 45.4% of 2-pronuclei oocytes developed into a morphologically good-quality embryo on day 3 after intracytoplasmic sperm injection. Fresh ET resulted in two ongoing pregnancies (2/37; 5.4%). Deferred vitrified-warmed ET led to an ongoing pregnancy rate of 34.6% (9/24). Three healthy babies were born and eight pregnancies were still ongoing. Oocytes retrieved from follicles with a diameter of <6 mm grow during a 40-hour IVM culture can acquire full competence in vitro, as illustrated by their development into healthy offspring. Endometrial quality appears to be a crucial determinant of pregnancy after nonhCG-triggered IVM. Copyright © 2012 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

The integrin-binding motif RGDS induces protein tyrosine phosphorylation without activation in Bufo arenarum (Amphibia) oocytes.

PubMed

Mouguelar, Valeria S; Cabada, Marcelo O; Coux, Gabriela

2011-05-01

Integrins are cell adhesion molecules that are thought to be involved in sperm-oocyte interaction. Nevertheless, their function in mammalian fertilization is still controversial, as different species behave differently. In amphibians, their role is mainly supported by Xenopus laevis studies, where RGDS peptide induces oocyte activation. We recently provided evidence suggesting the presence and involvement of integrins in the interaction of the oocyte plasma membrane (PM) with sperm in the amphibian Bufo arenarum. In order to understand the role of integrin homologs in oocytes and their possible contribution to egg activation mechanisms, we examined the presence of integrin subunits and the effect of RGDS peptide on oocytes and during fertilization. Western blot studies detected integrin subunits α5, αV and β1 in oocytes. In sperm, we could detect only the αV integrin subunit. We found that RGDS peptide was unable to elicit egg activation or MAPK dephosphorylation, but can induce reversible inhibition of fertilization. A similar partial inhibition was produced by an anti-β1 integrin antibody. Using an anti-phosphotyrosine antibody we found major changes in phosphotyrosine-containing proteins in egg extracts minutes after fertilization. Cytosol and PMs isolated from oocytes and fertilized eggs showed additional fertilization-induced phosphorylated proteins. Some of these were also present in cytosol and PMs from RGDS-treated oocytes (partially mimicking fertilization). These findings suggest that B. arenarum fertilization involves integrins (e.g. β1 subunit) as adhesion proteins. Our data support the view that RGDS-binding receptors may function as signaling receptors in B. arenarum oocytes, but integrin engagement by RGDS is not sufficient for oocyte activation.

Molecular and Cellular Mechanisms of Sperm-Oocyte Interactions Opinions Relative to in Vitro Fertilization (IVF)

PubMed Central

Anifandis, George; Messini, Christina; Dafopoulos, Konstantinos; Sotiriou, Sotiris; Messinis, Ioannis

2014-01-01

One of the biggest prerequisites for pregnancy is the fertilization step, where a human haploid spermatozoon interacts and penetrates one haploid oocyte in order to produce the diploid zygote. Although fertilization is defined by the presence of two pronuclei and the extraction of the second polar body the process itself requires preparation of both gametes for fertilization to take place at a specific time. These preparations include a number of consecutive biochemical and molecular events with the help of specific molecules and with the consequential interaction between the two gametes. These events take place at three different levels and in a precise order, where the moving spermatozoon penetrates (a) the outer vestments of the oocyte, known as the cumulus cell layer; (b) the zona pellucida (ZP); where exocytosis of the acrosome contents take place and (c) direct interaction of the spermatozoon with the plasma membrane of the oocyte, which involves a firm adhesion of the head of the spermatozoon with the oocyte plasma membrane that culminates with the fusion of both sperm and oocyte membranes (Part I). After the above interactions, a cascade of molecular signal transductions is initiated which results in oocyte activation. Soon after the entry of the first spermatozoon into the oocyte and oocyte activation, the oocyte’s coat (the ZP) and the oocyte’s plasma membrane seem to change quickly in order to initiate a fast block to a second spermatozoon (Part II). Sometimes, two spermatozoa fuse with one oocyte, an incidence of 1%–2%, resulting in polyploid fetuses that account for up to 10%–20% of spontaneously aborted human conceptuses. The present review aims to focus on the first part of the human sperm and oocyte interactions, emphasizing the latest molecular and cellular mechanisms controlling this process. PMID:25054321

N-octanoylated ghrelin peptide inhibits bovine oocyte meiotic resumption.

PubMed

Xu, X L; Bai, J H; Feng, T; Xiao, L L; Song, Y Q; Xiao, Y X; Liu, Y

2018-07-01

Studies have shown that ghrelin plays an important role in the mammalian reproductive system, including the central, gonadal levels, and also during in vitro maturation of oocytes; however, the functions of ghrelin in bovine oocyte meiosis require further investigation. We aimed to evaluate the effects of an n-octanoylated ghrelin peptide on oocyte meiotic resumption and the developmental competence of mature oocytes in vitro. design: The expression of GHRL (encoding ghrelin) mRNA and its receptor (the growth hormone secretagogue receptor, GHSR) in the cumulus-oocyte complex (COCs), denuded oocytes (DOs), and cumulus cells (CCs) was assessed using quantitative real-time reverse transcription PCR (qRT-PCR), and the effects of the n-octanoylated ghrelin peptide on meiotic resumption were studied at four different doses (0, 10, 50, and 100 ng/mL) in a 6 h culture system. qRT-PCR analysis showed that GHRL and GHSR mRNAs were expressed in all tested samples; however, GHRL was predominantly expressed in DOs, and GHSR was predominantly expressed in CCs. Germinal vesicle breakdown was inhibited significantly by 50 ng/mL ghrelin compared with that in the negative control (P < 0.05). Further studies showed that n-octanoylated ghrelin increased the levels of cAMP and cGMP in the CCs and DOs, which inhibited the meiotic resumption of bovine oocytes. And the inhibitory role in the developmental competence of mature oocytes were also included, ghrelin could significantly improve the cleavage rate (P < 0.05) and blastocyst rate (P < 0.05). N-octanoylated ghrelin maintained bovine oocytes meiotic arrest and further improved their developmental competence; therefore, n-octanoylated ghrelin could be considered as a potential pharmaceutical inhibitor of meiosis for the in vitro maturation of bovine oocytes. Copyright © 2018 Elsevier Inc. All rights reserved.

Effects of mineral supplements on ovulation and maturation of dog oocytes.

PubMed

Kim, Min Jung; Oh, Hyun Ju; Park, Jung Eun; Kim, Geon A; Park, Eun Jung; Jang, Goo; Lee, Byeong Chun

2012-07-01

The aim of this study was to assess the effects of trace mineral supplements near the time of ovulation on the number of ovulated oocytes, in vivo oocyte maturation and pregnancy for dog cloning. Sixteen oocyte donor dogs were used in each control and mineral supplement group, and 136 and 166 corpora lutea were counted from each group. No significant difference was observed between oocyte recovery rates in the control (91.2 ± 2.7%) and mineral (89.9 ± 2.7) groups. Proportions of mature (86.2 ± 7.2 and 88.4 ± 6.8%) and aged (13.8 ± 7.2 and 11.6 ± 6.8%) oocytes were not different in the control and mineral groups, respectively. Oocytes with fair (91.5 ± 3.6 and 93.6 ± 2.1%) and poor (8.5 ± 3.6 and 6.4 ± 2.1%) quality also showed no difference between the control and mineral groups. The concentrations of manganese and ferrous iron were higher and lower on the day of ovulation, respectively, in both groups, but trace element concentrations in peripheral blood were not affected by mineral treatment. Oocytes were used to make cloned embryos; after embryo transfer, four and two pups were delivered from the control and mineral group, respectively, but there was no difference in the delivery rate (4.6 and 2.7%). In conclusion, intravenous mineral supplements administered once close to the LH surge in oocyte donor dogs and recipients had no effect on the number of ovulated oocytes, in vivo oocyte maturation or pregnancy in dog cloning in this study. Copyright © 2012 Elsevier Inc. All rights reserved.

Somatic cells initiate primordial follicle activation and govern the development of dormant oocytes in mice.

PubMed

Zhang, Hua; Risal, Sanjiv; Gorre, Nagaraju; Busayavalasa, Kiran; Li, Xin; Shen, Yan; Bosbach, Benedikt; Brännström, Mats; Liu, Kui

2014-11-03

The majority of oocytes in the mammalian ovary are dormant oocytes that are enclosed in primordial follicles by several somatic cells, which we refer to as primordial follicle granulosa cells (pfGCs). Very little is known, however, about how the pfGCs control the activation of primordial follicles and the developmental fates of dormant oocytes. By targeting molecules in pfGCs with several mutant mouse models, we demonstrate that the somatic pfGCs initiate the activation of primordial follicles and govern the quiescence or awakening of dormant oocytes. Inhibition of mTORC1 signaling in pfGCs prevents the differentiation of pfGCs into granulosa cells, and this arrests the dormant oocytes in their quiescent states, leading to oocyte death. Overactivation of mTORC1 signaling in pfGCs accelerates the differentiation of pfGCs into granulosa cells and causes premature activation of all dormant oocytes and primordial follicles. We further show that pfGCs trigger the awakening of dormant oocytes through KIT ligand (KITL), and we present an essential communication network between the somatic cells and germ cells that is based on signaling between the mTORC1-KITL cascade in pfGCs and KIT-PI3K signaling in oocytes. Our findings provide a relatively complete picture of how mammalian primordial follicles are activated. The microenvironment surrounding primordial follicles can activate mTORC1-KITL signaling in pfGCs, and these cells trigger the awakening of dormant oocytes and complete the process of follicular activation. Such communication between the microenvironment, somatic cells, and germ cells is essential to maintaining the proper reproductive lifespan in mammals. Copyright © 2014 Elsevier Ltd. All rights reserved.

Accumulation of electrophilic aldehydes during postovulatory aging of mouse oocytes causes reduced fertility, oxidative stress, and apoptosis.

PubMed

Lord, Tessa; Martin, Jacinta H; Aitken, R John

2015-02-01

With increasing periods of time following ovulation, the metaphase II (MII)-stage oocyte experiences overproduction of reactive oxygen species and elevated levels of lipid peroxidation that are implicitly linked with functional deficiencies acquired during postovulatory oocyte aging. We have demonstrated that the electrophilic aldehydes 4-hydroxynonenal (4HNE), malondialdehyde, and acrolein are by-products of nonenzymatic lipid peroxidation in the murine MII-stage oocyte, adducting to multiple proteins within the cell. The covalent modification of oocyte proteins by these aldehydes increased with extended periods of time postovulation; the mitochondrial protein succinate dehydrogenase (SDHA) was identified as a primary target for 4HNE adduction. Time- and dose-dependent studies revealed that exposure to elevated levels of electrophilic aldehydes causes mitochondrial reactive oxygen species production, lipid peroxidation, loss of mitochondrial membrane potential, and eventual apoptosis within the MII oocyte, presumably as a consequence of electron transport chain collapse following SDHA adduction. Additionally, we have determined that short-term exposure to low doses of 4HNE dramatically impairs the oocyte's ability to participate in fertilization and support embryonic development; however, this loss of functionality can be prevented by supplementation with the antioxidant penicillamine. In conclusion, this study has revealed that the accumulation of electrophilic aldehydes is linked to postovulatory oocyte aging, causing reduced fertility, oxidative stress, and apoptosis of this highly specialized cell. These data highlight the importance of timely fertilization of the mammalian oocyte postovulation and emphasize the potential advantages associated with antioxidant supplementation of oocyte culture medium in circumstances where reinsemination of oocytes may be desirable (i.e., rescue intracytoplasmic sperm injection), or where in vitro fertilization may be delayed. © 2015 by the Society for the Study of Reproduction, Inc.

Impact of vitrification on human oocytes before and after in vitro maturation: A systematic review and meta-analysis.

PubMed

Mohsenzadeh, Mehdi; Salehi-Abargouei, Amin; Tabibnejad, Nasim; Karimi-Zarchi, Mojgan; Khalili, Mohammad Ali

2018-05-21

There are controversies regarding in vitro maturation (IVM) procedure, the time of storing frozen oocytes and maturation stage of vitrified oocytes and its impact on oocytes fertilization capability. The aim of this systematic review and meta-analysis was to evaluate the impact of vitrification on human oocytes during IVM procedure. A systematic review with meta-analysis was undertaken. Main search terms were those related key words. We searched Medline, Embase, Scopus and ISI web of science to detect English-language studies. The final search was performed on 27 January 2018. The original articles which studied laboratory outcomes after vitrification of MII or GV oocytes before or after IVM were included. Exclusion criteria were animal trials and the studies that performed cryopreservation using slow-freeze method. Oocyte maturation, survival, fertilization and cleavage rates were assessed. Bias and quality assessments were applied. 2476 articles were screened and after duplicates removing together with application of inclusion and exclusion criteria, 14 studies assessed for eligibility. Finally 5 studies included for analysis. All studies compared laboratory outcomes between oocytes that vitrified at the GV stage and those which firstly matured in vitro, and then vitrified. Meta-analysis showed that vitrification of oocytes at GV stage had a negative impact on maturation rate (RR = 1.28, 95% CI: 0.96-1.70); but not on cleavage rate (RR = 1.07, 95% CI: 0.70-1.64); fertilization rate (RR = 0.99, 95% CI: 0.85-1.14) and survival rate(RR = 1.01, 95% CI: 0.96-1.06). In general, Based on our results, oocyte vitrification decreases the maturation rate. In addition, survival, fertilization as well as cleavage rates did not significantly differ between the oocytes vitrified before IVM versus oocytes vitrified after IVM. Copyright © 2018. Published by Elsevier B.V.

Outcomes of pregnancies achieved by double gamete donation: A comparison with pregnancies obtained by oocyte donation alone.

PubMed

Preaubert, Lise; Vincent-Rohfritsch, Aurélie; Santulli, Pietro; Gayet, Vanessa; Goffinet, François; Le Ray, Camille

2018-03-01

Women increasingly resort to oocyte donation to become pregnant. The high risk of preeclampsia found in oocyte donation pregnancies and the separate risk of preeclampsia associated with sperm donation may be cumulative in double donation pregnancies. We aimed to study the obstetrical and perinatal outcomes of pregnancies obtained by double donation (both oocyte and sperm) in comparison with those obtained by oocyte donation alone (oocyte donation and partner's sperm). This cohort study included all women aged 43 and older who became pregnant after oocyte donation and gave birth between 2010 and 2016 in a tertiary maternity center. Primary outcomes were preeclampsia and hypertensive gestational disorders. Secondary outcomes were gestational diabetes, placental abnormalities, postpartum hemorrhage, perinatal death, and preterm delivery. We used univariate and multivariate analysis to compare IVF with double donation and IVF with oocyte donation alone for obstetric and perinatal outcomes. 247 women, 53 with double donations and 194 with oocyte donations alone, gave birth to 339 children. We observed no significant differences between groups for any obstetric or perinatal complications, except for the risk of gestational diabetes, which was more frequent in women with double donations compared with oocyte donation alone (26.4% vs. 12.9%, P = 0.02) and remained significant after adjustment (aOR = 2.80 95%CI[1.26-6.17]). Rates of gestational hypertension and preeclampsia were high, but similar between groups (20.7% vs. 26.3%, P = 0.41, and 18.9% vs. 17.5%, P = 0.82). Women undergoing oocyte donation should be fully informed of its high rates of obstetric and perinatal risks. However, except for a higher observed risk of gestational diabetes, double donation does not appear to be associated with a higher risk of complications than oocyte donation alone. Copyright © 2017 Elsevier B.V. All rights reserved.

Chromatin remodeling in somatic cells injected into mature pig oocytes.

PubMed

Bui, Hong-Thuy; Van Thuan, Nguyen; Wakayama, Teruhiko; Miyano, Takashi

2006-06-01

We examined the involvement of histone H3 modifications in the chromosome condensation and decondensation of somatic cell nuclei injected into mature pig oocytes. Nuclei of pig granulosa cells were transferred into in vitro matured intact pig oocytes, and histone H3 phosphorylation, acetylation, and methylation were examined by immunostaining with specific antibodies in relation to changes in chromosome morphology. In the condensed chromosomes of pig oocytes at metaphase II, histone H3 was phosphorylated at serine 10 (H3-S10) and serine 28 (H3-S28), and methylated at lysine 9 (H3-K9), but was not acetylated at lysine 9, 14 and 18 (H3-K9, H3-K14 and H3-K18). During the first 2 h after nuclear transfer, a series of events were observed in the somatic nuclei: nuclear membrane disassembly; chromosome condensation to form a metaphase-like configuration; an increase in histone H3 phosphorylation levels (H3-S10 and H3-S28). Next, pig oocytes injected with nuclei of somatic cells were electroactivated and the chromosome morphology of oocytes and somatic cells was examined along with histone modifications. Generally, chromosomes of the somatic cells showed a similar progression of cell cycle stage to that of oocytes, through anaphase II- and telophase II-like stages then formed pronucleus-like structures, although the morphology of the spindles differed from that of oocyte spindles. The chromosomes of somatic cells also showed changes in histone H3 dephosphorylation and reacetylation, similar to oocytes. In contrast, histone H3 methylation (H3-K9) of somatic cell nuclei did not show any significant change after injection and electroactivation of the oocytes. These results suggest that nuclear remodeling including histone H3 phosphorylation and acetylation of injected somatic nuclei took place in the oocytes under regulation by the oocyte cytoplasm.

Expanding reproductive lifespan: a cost-effectiveness study on oocyte freezing.

PubMed

van Loendersloot, L L; Moolenaar, L M; Mol, B W J; Repping, S; van der Veen, F; Goddijn, M

2011-11-01

The average age of women bearing their first child has increased strongly. This is an important reproductive health problem as fertility declines with increasing female age. Unfortunately, IVF using fresh oocytes cannot compensate for this age-related fertility decline. Oocyte freezing could be a solution. We used the Markov model to estimate the cost-effectiveness of three strategies for 35-year-old women who want to postpone pregnancy till the age of 40: Strategy 1: women undergo three cycles of ovarian hyperstimulation at age 35 for oocyte freezing, then at age 40, use these frozen oocytes for IVF; Strategy 2: women at age 40 attempt to conceive without treatment; and the reference strategy: women at age 40 attempt to conceive and, if not pregnant after 1 year, undergo IVF. Sensitivity analyses were carried out to investigate assumptions of the model and to identify which model inputs had most impact on the results. Oocyte freezing (Strategy 1) resulted in a live birth rate of 84.5% at an average cost of €10,419. Natural conception (Strategy 2) resulted in a live birth rate of 52.3% at an average cost of €310 per birth. IVF (the reference strategy) resulted in a cumulative live birth rate of 64.6% at an average cost of €7798. The cost per additional live birth for the oocyte freezing strategy was €13,156 compared to the IVF strategy. If at least 61% of the women return to collect their oocytes, and if there is a willingness to pay €19,560 extra per additional live birth, the oocyte freezing strategy is the most cost-effective strategy. Oocyte freezing is more cost effective compared to IVF, if at least 61% of the women return to collect their oocytes and if one is willing to pay €19,560 extra per additional live birth. Our Markov model shows that, considering all the used assumptions, oocyte freezing provides more value for money than IVF.

Differences in the Kinetic of the First Meiotic Division and in Active Mitochondrial Distribution between Prepubertal and Adult Oocytes Mirror Differences in their Developmental Competence in a Sheep Model

PubMed Central

Leoni, Giovanni Giuseppe; Palmerini, Maria Grazia; Satta, Valentina; Succu, Sara; Pasciu, Valeria; Zinellu, Angelo; Carru, Ciriaco; Macchiarelli, Guido; Nottola, Stefania Annarita; Naitana, Salvatore; Berlinguer, Fiammetta

2015-01-01

Our aim is to verify if oocyte developmental potential is related to the timing of meiotic progression and to mitochondrial distribution and activity using prepubertal and adult oocytes as models of low and high developmental capacity respectively. Prepubertal and adult oocytes were incorporated in an in vitro maturation system to determine meiotic and developmental competence and to assess at different time points kinetic of meiotic maturation, 2D protein electrophoresis patterns, ATP content and mitochondria distribution. Maturation and fertilization rates did not differ between prepubertal and adult oocytes (95.1% vs 96.7% and 66.73% vs 70.62% respectively for prepubertal and adult oocytes). Compared to adults, prepubertal oocytes showed higher parthenogenesis (17.38% vs 2.08% respectively in prepubertals and adults; P<0.01) and polispermy (14.30% vs 2.21% respectively in prepubertals and adults; P<0.01), lower cleavage rates (60.00% vs 67.08% respectively in prepubertals and adults; P<0.05) and blastocyst output (11.94% vs 34.% respectively in prepubertals and adults; P<0.01). Prepubertal oocytes reached MI stage 1 hr later than adults and this delay grows as the first meiotic division proceeds. Simultaneously, the protein pattern was altered since in prepubertal oocytes it fluctuates, dropping and rising to levels similar to adults only at 24 hrs. In prepubertal oocytes ATP rise is delayed and did not reach levels comparable to adult ones. CLSM observations revealed that at MII, in the majority of prepubertal oocytes, the active mitochondria are homogenously distributed, while in adults they are aggregated in big clusters. Our work demonstrates that mitochondria and their functional aggregation during maturation play an active role to provide energy in terms of ATP. The oocyte ATP content determines the timing of the meiotic cycle and the acquisition of developmental competence. Taken together our data suggest that oocytes with low developmental competence have a slowed down energetic metabolism which delays later development. PMID:25893245

High Peak Estradiol/Mature Oocyte Ratio Predicts Lower Clinical Pregnancy, Ongoing Pregnancy, and Live Birth Rates in GnRH Antagonist Intracytoplasmic Sperm Injection Cycles.

PubMed

Sandoval, Juan S; Steward, Ryan G; Chen, Chen; Li, Yi-Ju; Price, Thomas M; Muasher, Suheil J

2016-01-01

To define the relationship between peak estradiol (E2)/mature oocyte ratio and pregnancy outcomes in gonadotropin-releasing hormone (GnRH) antagonist intracytoplasmic sperm injection (ICSI) cycles. Retrospective cohort study in the setting of an academic reproductive medicine practice. Records from 162 fresh, autologous, GnRH antagonist ICSI cycles performed between 2009 and 2012 .were analyzed. The main outcome measures were rates of clinical pregnancy (CPR), ongoing pregnancy (OPR), and live birth (LBR). For the primary analysis, 4 groups were created based on peak E2/mature oocyte ratio (group 1: <200, group 2: 200-300, group 3: 300-400, and group 4: >400 pg/mL/oocyte). After adjusting for age, basal FSH, and the number of mature oocytes, a significantly lower OPR was seen in group 4 as compared to group I (OR 0.15, 95% CI 0.03-0.86; p=0.032) and group 3 (OR 0.17, 95% CI 0.03-0.98; p=0.048), respectively. The adjusted LBR was also significantly lower in group 4 as compared to group 1 (OR 0.15, 95% CI 0.03-0.83; p=0.030). In a secondary analysis, 3 ranges of peak E2/ mature oocyte ratio (<200, 200-400, and >400 pg/ mL/oocyte) were compared between low, normal, and high responders (<6, 6-15, and >15 mature oocytes, respectively). Clinical pregnancy rate, OPR, and LBR were all lower in normal responders when the E2/oocyte ratio exceeded 400 pg/mL/oocyte as compared to <200 pg/mL/oocyte and 200-300 pg/mL/oocyte (CPR 1% vs. 16% and 32%, respectively, p=0.017; OPR 0 vs. 15% and 27%, respectively, p=0.011; and LBR 0 vs. 13% and 26%, respectively, p=0.018). Very elevated peak E2/mature oocyte ratio is associated with a lower CPR, OPR, and LBR in fresh, autologous, GnRH antagonist ICSI cycles.

Pronuclear formation by ICSI using chemically activated ovine oocytes and zona pellucida bound sperm.

PubMed

Hernández-Pichardo, J E; Ducolomb, Y; Romo, S; Kjelland, M E; Fierro, R; Casillas, F; Betancourt, M

2016-01-01

In order to improve ICSI, appropiate sperm selection and oocyte activation is necessary. The objective of the present study was to determine the efficiency of fertilization using ICSI with chemically activated ovine oocytes and sperm selected by swim up (SU) or swim up + zona pellucida (SU + ZP) binding. Experiment 1, 4-20 replicates with total 821 in vitro matured oocytes were chemically activated with ethanol, calcium ionophore or ionomycin, to determine oocyte activation (precense of one PN). Treatments showed similar results (54, 47, 42 %, respectively) but statistically differents ( P  < 0.05) than mechanical activated oocytes in sham, ICSI and sham injection (13, 25, 32 %, respectively) (10-17 replicates; n  = 429). Experiment 2: Twelve ejaculates and 28 straws of semen were used (11-19 replicates). Sperm were selected by SU in BSA-TCM 199-H medium. A total of 2,294 fresh sperm and 2,760 from frozen-thawed semen were analyzed after SU or SU + ZP binding. Fresh sperm selected by SU showed acrosome reaction (AR) of 59 %, the sperm selected by SU + ZP binding increased AR to 91 %. In comparison, the AR of frozen-thawed sperm using SU or SU + ZP binding was 77 and 86 %, respectively ( P  < 0.05). Experiment 3: fertilization in 200 mechanical activativated oocytes (17 replicates) was 4 %, but fertilization increased in ethanol activated oocytes after ICSI (12-28 %) (5-6 replicates). When fresh sperm only selected by SU were injected to 123 oocytes, a fertilization rate (28 %) was achieved; in sperm selected by SU + ZP was 25 % (73 oocytes). In comparison, in frozen-thawed sperm selected by SU, fertilization was 13 % (70 oocytes), whereas sperm from SU + ZP binding displayed 12 % (51 oocytes) ( P  > 0.05). Chemical activation induces higher ovine oocyte activation than mechanical activation. Ethanol slightly displays higher oocyte activation than calcium ionophore and ionomicine. Sperm selection with SU + ZP increased AR/A and AR/D rates in comparison with SU in fresh and frozen-thawed sperm. According to this, in terms of fertilization rates, chemical activation after ICSI increased oocyte PN formation compared to mechanical activation. Also, fresh sperm treated with SU and SU + ZP were significantly different than frozen-thawed sperm, but between sperm treatments no significant differences were obtained.

Kinetics of nuclear maturation and effect of holding ovaries at room temperature on in vitro maturation of camel (Camelus dromedarius) oocytes.

PubMed

Wani, N A; Nowshari, M A

2005-07-01

Experiments were conducted to investigate kinetics of in vitro nuclear maturation and the effect of storing ovaries at room temperature on initial chromatin configuration and in vitro maturation of dromedary camel oocytes. Cumulus oocyte complexes (COCs) were collected from slaughterhouse ovaries and matured in vitro for 4-48h. At every 4h interval (starting from 0 to 48 h), groups of oocytes were fixed, stained and evaluated for the status of nuclear chromatin. Oocytes were categorized as germinal vesicle (GV), diakinesis (DK), metaphase-I (M-I), anaphase-I (A-I), metaphase-II (M-II) stage and those with degenerated, fragmented, activated or without a visible chromatin as others. At the start of culture, 74% (66/89) oocytes were at GV stage, 13% (12/89) at DK and 12% (11/89) were classified as others. Germinal vesicle breakdown started spontaneously in culture and at 20 h of culture 97% oocytes had already completed this process. After 8 and 16 h of maturation the highest proportion of oocytes (42%, 48/114 and 41%, 51/123) were at DK and M-I stage, respectively. The proportions of oocytes reaching M-II stage at 32 (42%, 50/118), 36 (45%, 47/104), 40 (49%, 57/117), 44 (52%, 103/198) and 48 h (46%, 55/120) of culture were not different from each other (P>0.05). The proportion of oocytes categorized as others, however, increased after 40 h of culture and was higher (P<0.05) at 48 h compared with other maturation periods. There was no difference (P>0.05) in the proportion of oocytes reaching M-II stage from the ovaries collected and stored in normal saline solution (NSS) at room temperature for 12h (43%, 64/148) and those collected in warm NSS (37 degrees C) and processed immediately after arrival in laboratory (49%, 57/117). However, low number of oocytes reached M-II stage from ovaries collected in warm NSS but stored at room temperature (29%, 37/128) compared with other two groups (P<0.05). It may be concluded that dromedary oocytes require 32-44h of in vitro culture to have an optimum number of oocytes in M-II stage. However, further studies are required to find out the most appropriate maturation period, which will result in the further development of these oocytes after IVF, ICSI, parthenogenetic activation or nuclear transfer. Ovaries can be collected and stored in normal saline solution at room temperature for 12h without any appreciable effect on the nuclear maturation of the oocytes.

Improved cryotolerance and developmental potential of in vitro and in vivo matured mouse oocytes by supplementing with a glutathione donor prior to vitrification.

PubMed

Trapphoff, Tom; Heiligentag, Martyna; Simon, Jenny; Staubach, Nora; Seidel, Thorsten; Otte, Kathrin; Fröhlich, Thomas; Arnold, Georg J; Eichenlaub-Ritter, Ursula

2016-12-01

Can supplementation of media with a glutathione (GSH) donor, glutathione ethyl ester (GEE), prior to vitrification protect the mouse oocyte from oxidative damage and critical changes in redox homeostasis, and thereby improve cryotolerance? GEE supplementation supported redox regulation, rapid recovery of spindle and chromosome alignment after vitrification/warming and improved preimplantation development of mouse metaphase II (MII) oocytes. Cryopreservation may affect mitochondrial functionality, induce oxidative stress, and thereby affect spindle integrity, chromosome segregation and the quality of mammalian oocytes. GEE is a membrane permeable GSH donor that promoted fertilization and early embryonic development of macaque and bovine oocytes after IVM. Two experimental groups consisted of (i) denuded mouse germinal vesicle (GV) oocytes that were matured in vitro in the presence or absence of 1 mM GEE (IVM group 1) and (ii) in vivo ovulated (IVO) MII oocytes that were isolated from the ampullae and exposed to 1 mM GEE for 1 h prior to vitrification (IVO group 2). Recovery of oocytes from both groups was followed after CryoTop vitrification/warming for up to 2 h and parthenogenetic activation. Reactive oxygen species (ROS), spindle morphology and chromosome alignment were analyzed by confocal laser scanning microscopy (CLSM) and polarization microscopy in control and GEE-supplemented MII oocytes. The relative overall intra-oocyte GSH content was assessed by analysis of monochlorobimane (MBC)-GSH adduct fluorescence in IVM MII oocytes. The GSH-dependent intra-mitochondrial redox potential (E m GSH ) of IVM MII oocytes was determined after microinjection with specific mRNA at the GV stage to express a redox-sensitive probe within mitochondria (mito-Grx1-roGFP2). The absolute negative redox capacity (in millivolts) was determined by analysis of fluorescence of the oxidized versus the reduced form of sensor by CLSM and quantification according to Nernst equation. Proteome analysis was performed by quantitative 2D saturation gel electrophoresis (2D DIGE). Since microinjection and expression of redox sensor mRNA required removal of cumulus cells, and IVM of denuded mouse oocytes in group 1 induces zona hardening, the development to blastocysts was not assessed after IVF but instead after parthenogenetic activation of vitrified/warmed MII oocytes from both experimental groups. IVM of denuded mouse oocytes in the presence of 1 mM GEE significantly increased intra-oocyte GSH content. ROS was not increased by CryoTop vitrification but was significantly lower in the IVM GEE group compared to IVM without GEE before vitrification and after recovery from vitrification/warming (P < 0.001). Vitrification alone significantly increased the GSH-dependent intra-mitochondrial redox capacity after warming (E m GSH , P < 0.001) in IVM oocytes, presumably by diffusion/uptake of cytoplasmic GSH into mitochondria. The presence of 1 mM GEE during IVM increased the redox capacity before vitrification and there was no further increase after vitrification/warming. None of the reproducibly detected 1492 spots of 2D DIGE separated proteins were significantly altered by vitrification or GEE supplementation. However, IVM of denuded oocytes significantly affected spindle integrity and chromosome alignment right after warming from vitrification (0 h) in group 1 and spindle integrity in group 2 (P < 0.05). GEE improved recovery in IVM group as numbers of oocytes with unaligned chromosomes and aberrant spindles was not significantly increased compared to unvitrified controls. The supplementation with GEE for 1 h before vitrification also supported more rapid recovery of spindle birefringence. GEE improved significantly development to the 2-cell stage for MII oocytes that were activated directly after vitrification/warming in both experimental groups, and also the blastocyst rate in the IVO GEE-supplemented group compared to the controls (P < 0.05). None LIMITATIONS, REASONS FOR CAUTION: The studies were carried out in a mouse model, in IVM denuded rather than cumulus-enclosed oocytes, and in activated rather than IVF MII oocytes. Whether the increased GSH-dependent intra-mitochondrial redox capacity also improves male pronuclear formation needs to be studied further experimentally. The influence of GEE supplementation requires also further examination and optimization in human oocytes before it can be considered for clinical ART. Although GEE supplementation did not alter the proteome at MII, the GSH donor may support cellular homeostasis and redox regulation and, thus, increase developmental competence. While human MII oocyte vitrification is an established procedure, GEE might be particularly beneficial for oocytes that suffer from oxidative stress and reduced redox capacity (e.g. aged oocytes) or possess low GSH due to a reduced supply of GSH from cumulus. It might also be of relevance for immature human oocytes that develop without cumulus to MII in vitro (e.g. in ICSI cycles) for ART. The study has been supported by the German Research Foundation (DFG FOR 1041; EI 199/3-2). There are no conflict of interests. © The Author 2016. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Cloning and characterization of a novel oocyte-specific gene encoding an F-Box protein in rainbow trout (Oncorhynchus mykiss)

USDA-ARS?s Scientific Manuscript database

Oocyte-specific genes play critical roles in oogenesis, folliculogenesis and early embryonic development. Through analysis of expressed sequence tags (ESTs) from a rainbow trout oocyte cDNA library, we identified a novel transcript which is represented by multiple ESTs derived only from the oocyte c...

Cloning and characterization of a novel oocyte-specific gene encoding an F-Box protein in rainbow trout (Oncorhynchus mykiss)

USDA-ARS?s Scientific Manuscript database

Oocyte-specific genes play critical roles in oogenesis, folliculogenesis and early embryonic development. Through analysis of expressed sequence tags (ESTs) from a rainbow trout oocyte cDNA library, we identified a novel transcript which is represented by ESTs only from the oocyte library. The novel...

A comparison of the Cook single lumen immature ovum IVM needle to the Steiner-Tan pseudo double lumen flushing needle for oocyte retrieval for IVM.

PubMed

Rose, B I; Laky, D

2013-06-01

This study compared the impact of using the Steiner-Tan pseudo double lumen needle for antral follicle oocyte retrieval to using a conventional non-flushing needle. The Steiner-Tan needle has a much smaller dead space than the needles commonly used for IVM oocyte retrievals. This was a retrospective cohort study. The patient population was determined by the time period in which a patient underwent IVM in a single physician's IVF practice. The following data was abstracted from clinical and embryology records: oocytes retrieved, oocytes matured, early maturing oocytes, oocytes fertilized, embryo quality measures, retrieval time, needle punctures, clot formation, and clinical pregnancy rate. The Steiner-Tan needle did not increase the number of oocytes retrieved. It also did not increase the time required for retrieval. However, flushing of antral follicles significantly decreased clot formation in fluid aspirates. Use of the Steiner-Tan needle also significantly decreased the number of vaginal needle punctures during each case. There was a trend toward improved embryo quality, but statistical power was inadequate to show a difference. The primary benefit of the Steiner-Tan needle was on the embryological aspects of IVM. Decreased blood and blood clots in the aspirates made an IVM retrieval more like conventional IVF for the embryologist. The patient also experienced less tissue trauma without increasing anesthesia or surgical time. There was no improvement in the number of oocytes retrieved, but based on the results, we hypothesized that oocytes were more commonly retrieved from slightly large follicles than when using a routine needle.

Predictive value of bovine follicular components as markers of oocyte developmental potential.

PubMed

Matoba, Satoko; Bender, Katrin; Fahey, Alan G; Mamo, Solomon; Brennan, Lorraine; Lonergan, Patrick; Fair, Trudee

2014-01-01

The follicle is a unique micro-environment within which the oocyte can develop and mature to a fertilisable gamete. The aim of this study was to investigate the ability of a panel of follicular parameters, including intrafollicular steroid and metabolomic profiles and theca, granulosa and cumulus cell candidate gene mRNA abundance, to predict the potential of bovine oocytes to develop to the blastocyst stage in vitro. Individual follicles were dissected from abattoir ovaries, carefully ruptured under a stereomicroscope and the oocyte was recovered and individually processed through in vitro maturation, fertilisation and culture. The mean (±s.e.m.) follicular concentrations of testosterone (62.8±4.8 ngmL(-1)), progesterone (616.8±31.9 ngmL(-1)) and oestradiol (14.4±2.4 ngmL(-1)) were not different (P>0.05) between oocytes that formed (competent) or failed to form (incompetent) blastocysts. Principal-component analysis of the quantified aqueous metabolites in follicular fluid showed differences between oocytes that formed blastocysts and oocytes that degenerated; l-alanine, glycine and l-glutamate were positively correlated and urea was negatively correlated with blastocyst formation. Follicular fluid associated with competent oocytes was significantly lower in palmitic acid (P=0.023) and total fatty acids (P=0.031) and significantly higher in linolenic acid (P=0.036) than follicular fluid from incompetent oocytes. Significantly higher (P<0.05) transcript abundance of LHCGR in granulosa cells, ESR1 and VCAN in thecal cells and TNFAIP6 in cumulus cells was associated with competent compared with incompetent oocytes.

Prophase I Mouse Oocytes Are Deficient in the Ability to Respond to Fertilization by Decreasing Membrane Receptivity to Sperm and Establishing a Membrane Block to Polyspermy1

PubMed Central

Kryzak, Cassie A.; Moraine, Maia M.; Kyle, Diane D.; Lee, Hyo J.; Cubeñas-Potts, Caelin; Robinson, Douglas N.; Evans, Janice P.

2013-01-01

ABSTRACT Changes occurring as the prophase I oocyte matures to metaphase II are critical for the acquisition of competence for normal egg activation and early embryogenesis. A prophase I oocyte cannot respond to a fertilizing sperm as a metaphase II egg does, including the ability to prevent polyspermic fertilization. Studies here demonstrate that the competence for the membrane block to polyspermy is deficient in prophase I mouse oocytes. In vitro fertilization experiments using identical insemination conditions result in monospermy in 87% of zona pellucida (ZP)-free metaphase II eggs, while 92% of ZP-free prophase I oocytes have four or more fused sperm. The membrane block is associated with a postfertilization reduction in the capacity to support sperm binding, but this reduction in sperm-binding capacity is both less robust and slower to develop in fertilized prophase I oocytes. Fertilization of oocytes is dependent on the tetraspanin CD9, but little to no release of CD9 from the oocyte membrane is detected, suggesting that release of CD9-containing vesicles is not essential for fertilization. The deficiency in membrane block establishment in prophase I oocytes correlates with abnormalities in two postfertilization cytoskeletal changes: sperm-induced cortical remodeling that results in fertilization cone formation and a postfertilization increase in effective cortical tension. These data indicate that cortical maturation is a component of cytoplasmic maturation during the oocyte-to-egg transition and that the egg cortex has to be appropriately primed and tuned to be responsive to a fertilizing sperm. PMID:23863404

DNase I and II present in avian oocytes: a possible involvement in sperm degradation at polyspermic fertilisation.

PubMed

Stepińska, Urszula; Olszańska, Bozenna

2003-02-01

During polyspermic fertilisation in birds numerous spermatozoa enter the eggs, in contrast to the situation in mammals where fertilisation is monospermic. However, in birds only one of the spermatozoa which have entered an egg participates in zygote nucleus formation, while the supernumerary spermatozoa degenerate at early embryogenesis. Our previous work has demonstrated the presence in preovulatory quail oocytes of DNase I and II activities able to digest naked lambdaDNA/HindIII substrate in vitro. In the present studies, the activities of both DNases in quail oocytes at different stages of oogenesis and in ovulated mouse oocytes were assayed in vitro using the same substrate. Degradation of quail spermatozoa by quail oocyte extracts was also checked. Digestion of the DNA substrate was evaluated by electrophoresis on agarose gels. The activities of DNase I and II in quail oocytes increased during oogenesis and were the highest in mature oocytes. The activities were present not only in germinal discs but also in a thin layer of cytoplasm adhering to the perivitelline layer surrounding the yolk. At all stages of oogenesis the activity of DNase II was much higher than that of DNase I. DNA contained in spermatozoa was also degraded by the quail oocyte extracts under conditions optimal for both DNases. In contrast to what is observed in quail oocytes, no DNase activities were detected in ovulated mouse eggs; this is logical as they would be useless or even harmful in monospermic fertilisation. The possible role of DNase activities in avian oocytes, in degradation of accessory spermatozoa during polyspermic fertilisation, is discussed.

The effect of minimal concentration of ethylene glycol (EG) combined with polyvinylpyrrolidone (PVP) on mouse oocyte survival and subsequent embryonic development following vitrification.

PubMed

Wang, Yao; Okitsu, Osamu; Zhao, Xiao-Ming; Sun, Yun; Di, Wen; Chian, Ri-Cheng

2014-01-01

Vitrification techniques employ a relatively high concentration of cryoprotectant in vitrification solutions. Exposure of oocytes to high concentrations of cryoprotectant is known to damage the oocytes via both cytotoxic and osmotic effects. Therefore, the key to successful vitrification of oocytes is to strike a balance between the usage of minimal concentration of cryoprotectant without compromising their cryoprotective actions. The minimal concentration of ethylene glycol (EG) on mouse oocyte survival and subsequent embryonic development was evaluated following vitrification-warming and parthenogenetic activation. Polyvinylpyrrolidone (PVP) combined with EG on mouse oocyte survival and subsequent embryonic development as well as morphology of the spindle and chromosome alignment were also evaluated. Vitrification system was adapted with JY Straw and the cooling rate was approximately 442-500 °C/min. In contrast, the warming rate was approximately 2,210-2,652 °C/min. Survival rate of oocytes increased significantly when 15 % EG was combined with 2 % PVP in vitrification solution (VS). The effect of combination of EG and PVP was not significant when the concentration of EG was 20 % and higher. Although there were no significant differences in embryonic development, the percentage of abnormal spindle and chromosome alignment was significantly higher in the oocytes without 2 % PVP in VS. Our data provide a proof of principle for oocyte vitrification that may not require a high concentration of cryoprotectant. There are synergic effects of EG combined with PVP for oocyte vitrification, which may provide important information to the field in developing less cytotoxic VS.

Developmental competence of Dromedary camel (Camelus dromedarius) oocytes selected using brilliant cresyl blue staining.

PubMed

Fathi, Mohamed; Ashry, Mohamed; Salama, Ali; Badr, Magdy R

2017-08-01

The objectives of the present studies were to investigate the developmental capacity of dromedary camel oocytes selected by brilliant cresyl blue (BCB) staining and to investigate the expression of select transcripts in germinal vesicle (GV) stage oocytes. These transcripts included BMP15 and GDF9 as important transcripts for folliculogenesis and oocyte development, Zar1 and Mater as maternal transcripts required for embryonic development, Cyclin B1 and CDK1 as cell cycle regulators and Oct4 and STAT3 as transcription factors. Dromedary camel oocytes were retrieved from ovaries collected at a local slaughterhouse. After exposure to BCB staining, cumulus-oocyte complexes (COCs) from BCB+, BCB- and control (selected based on morphological criteria) groups were subjected to in vitro maturation, in vitro fertilization and in vitro culture. For gene expression studies, after BCB staining cumulus cells were stripped off and the completely denuded GV stage oocytes were used for RT-PCR analysis of selected transcripts. BCB+ oocytes showed higher maturation, and fertilization rates compared with BCB- and control groups. Indices of early embryonic development, namely, cleavage at 48 hours post insemination (hpi), and development to morula at day 5 and day 7 blastocyst rates were also significantly higher in the BCB+ group. RT-PCR revealed a higher expression of BMP15, GDF9, Zar1, Mater, Cyclin B1, CDK1, OCT4 and STAT3 in good quality oocytes that stained positively for BCB (BCB+). Collectively, results provide novel information about the use of BCB screening for selecting good quality oocytes to improve in vitro embryo production in the dromedary camel.

Effect of Fetal Mouse Lung Tissue Co-Culture on In Vitro Maturation of Mouse Immature Oocytes.

PubMed

Belbasi, Masomeh; Jorsaraei, Seyed Gholam Ali; Gholamitabar Tabari, Maryam; Khanbabaei, Ramzan

2017-10-01

The aim of this study was to evaluate the fetal mouse lung tissue co-culture on in vitro maturation (IVM) of mouse immature oocytes. In this experimental study, germinal vesicle (GV) oocytes from ovaries of a group of 25 female mice, 6-8 weeks of age, were dissected after being stimulated by 7.5 IU pregnant mare serum gonadotropin (PMSG) through an intraperitoneal (IP) injection. The fetal lung tissues were then prepared and cultured individually. A total number of 300 oocytes were cultured in the following three groups for 24 hours: control group (n=100) containing only base medium, group I (n=100) containing base medium co-cultured with 11.5- to 12.5-day old fetal mouse lung tissues, and group II (n=100) containing base medium co-cultured with 12.5- to 13.5-day old fetal mouse lung tissues. The proportion of GV and metaphase І (MI) oocytes matured into MІІ oocytes were compared among the three groups using analysis of variance (ANOVA). Correlation test were also used to evaluate the successful rate of IVM oocytes. The proportions of GV oocytes reaching MІІ stage were 46, 65, and 56%, in control, I and II groups, respectively (P<0.05). The percentage of the oocytes remaining at the GV stage were higher in control group as compared with two treatment groups (P<0.05). This study indicated that fetal mouse lung tissue co-culture method increased the percentage of GV oocytes reaching MII stage. Copyright© by Royan Institute. All rights reserved.

PTK2b function during fertilization of the mouse oocyte

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luo, Jinping; McGinnis, Lynda K.; Carlton, Carol

Highlights: • PTK2b is expressed in oocytes and is activated following fertilization. • PTK2b suppression in oocytes prevents fertilization, but not parthenogenetic activation. • PTK2b suppression prevents the oocyte from fusing with or incorporating bound sperm. • PTK2b suppressed oocytes that fail to fertilize do not exhibit calcium oscillations. - Abstract: Fertilization triggers rapid changes in intracellular free calcium that serve to activate multiple signaling events critical to the initiation of successful development. Among the pathways downstream of the fertilization-induced calcium transient is the calcium-calmodulin dependent protein tyrosine kinase PTK2b or PYK2 kinase. PTK2b plays an important role in fertilizationmore » of the zebrafish oocyte and the objective of the present study was to establish whether PTK2b also functions in mammalian fertilization. PTK2b was activated during the first few hours after fertilization of the mouse oocyte during the period when anaphase resumption was underway and prior to the pronuclear stage. Suppression of PTK2b kinase activity in oocytes blocked sperm incorporation and egg activation although sperm-oocyte binding was not affected. Oocytes that failed to incorporate sperm after inhibitor treatment showed no evidence of a calcium transient and no evidence of anaphase resumption suggesting that egg activation did not occur. The results indicate that PTK2b functions during the sperm-egg fusion process or during the physical incorporation of sperm into the egg cytoplasm and is therefore critical for successful development.« less

Comparison of two different dosage of GnRH agonist as ovulation trigger in oocyte donors: a randomized controled trial

PubMed Central

Zarcos, Sonia Morales; Mejía, Pamela Valdivieso; Stefani, Carla Donado; Martin, Pascual Sánchez; Martin, Fernando Sánchez

2017-01-01

Objective To compare the results obtained with two different GnRH agonist dosages: 0.3mg versus 0.4mg to trigger ovulation in oocyte donor cycles. Methods Experimental controlled randomized trial including 40 patients from a private practice center. The patients were randomized into two groups. Group A received a single dose of Triptorelin 0.3mg (Decapeptyl®) 36hours before pick-up. Group B patients received Triptorelin 0.4mg (Decapeptyl®) before pick-up to final oocyte maturation. We evaluated the total number of oocytes collected, the number of mature oocytes and total days of ovarian stimulation. Results The average of total collected oocytes were 16 (Group A) versus 15 (Group B), and the mean number of mature oocytes were 13 versus 12 respectively. The only variable showing a difference was the percentage of mature oocytes, which was greater in Group A, resulting in 84.6%, in contrast with those treated with 0.4mg of Triptorelin (78.6%), although these differences were not statistical significant (p=0.35). Days of stimulation did not differ between groups. No cases of empty follicle syndrome were reported. Conclusions We found that an increase from 0.3 to 0.4mg of triptorelin in an oocyte donation program might not improve outcomes. Nevertheless, more studies might be necessary, not only in oocyte donors but in sterile women as well, to evaluate how GnRH agonist dosage could affect the results among other factors. PMID:28837025

Establishment of an oocyte donor program. Donor screening and selection.

PubMed

Quigley, M M; Collins, R L; Schover, L R

1991-01-01

IVF with donated oocytes, followed by embryo placement in the uterus of a recipient who has been primed with exogenous steroids, is a successful treatment for special cases of infertility. Preliminary results indicate that the success rate in this situation is even greater than that usually seen with normal IVF (with placement of the embryos back into the uteri of the women from whom the oocytes were recovered). Although different sources for donated oocytes have been identified, the use of "excess" oocytes from IVF cycles and the attempted collection of oocytes at the time of otherwise indicated pelvic surgery have ethical and practical problems associated with their use. We have herein described the establishment of a successful program relying on anonymous volunteers who go through ovarian stimulation, monitoring, and oocyte recovery procedures solely to donate oocytes. The potential donors go through an exhaustive screening and education process before they are accepted in the program. Psychological evaluation of our potential donors indicated a great degree of turmoil in their backgrounds and a wide variety of motivations for actually participating. Despite the extensive educational and screening process, a substantial percentage of the donors did not complete a donation cycle, having either voluntarily withdrawn or been dropped because of lack of compliance. Further investigation of the psychological aspects of participating in such a program is certainly warranted. The use of donated oocytes to alleviate specific types of infertility is quite successful, but the application of this treatment is likely to be limited by the relative unavailability of suitable oocyte donors.

Ion currents involved in oocyte maturation, fertilization and early developmental stages of the ascidian Ciona intestinalis.

PubMed

Tosti, Elisabetta; Gallo, Alessandra; Silvestre, Francesco

2011-01-01

Electrophysiological techniques were used to study the role of ion currents in the ascidian Ciona intestinalis oocyte plasma membrane during different stages of growth, meiosis, fertilization and early development. Three stages of immature oocytes were discriminated in the ovary, with the germinal vesicle showing specific different features of growth and maturation. Stage-A (pre-vitellogenic) oocytes exhibited the highest L-type calcium current activity and were incompetent for meiosis resumption. Stage-B (vitellogenic) oocytes showed a progressive disappearance of calcium currents and the first appearance of sodium currents that remained high during the maturation process, up to the post-vitellogenic stage-C oocytes. The latter had acquired meiotic competence, undergoing spontaneous in vitro maturation and interacting with the spermatozoon. However, fertilized oocytes did not produce normal larvae, suggesting that cytoplasmic maturation may affect embryo development. In mature oocytes at the metaphase I stage, sodium currents were present and remained high up to the zygote stage. Oocytes fertilized in the absence of sodium showed significant reduction of the fertilization current amplitude and high development of anomalous "rosette" embryos. Current amplitudes became negligible in embryos at the 2- and 4-cell stage, whereas resumption of all the current activities occurred at the 8-cell embryo. Taken together, these results suggest: (i) an involvement of L-type calcium currents in initial oocyte meiotic progression and growth; (ii) a role of sodium currents at fertilization; (iii) a role of the fertilization current in ensuring normal embryo development. Copyright © 2011 Wiley Periodicals, Inc.

Histochemical and morphological features of biopsied and stripped oocytes from the Brazilian endangered teleost pirapitinga, Brycon nattereri (Characiformes).

PubMed

Maria, Alexandre N; Orfão, Laura H; Rizzo, Elizete; Ninhaus-Silveira, Alexandre; Viveiros, Ana T M

2015-06-01

The aim of the present study was to characterize biopsied and stripped oocytes from the Brazilian endangered teleost pirapitinga (Brycon nattereri) using histochemical and morphological analyses. Biopsied oocytes had a mean diameter of 2.225 mm (modal diameter: 2.312 mm), complete vitellogenesis and a central or slightly eccentric nucleus. Neutral polysaccharides were detected in the follicular cells, zona radiata and yolk globules, while acidic polysaccharides were detected in the follicular cells and cortical alveoli. Ten out of the 19 females treated with two doses of carp pituitary extract (cPE) released oocytes, which were also analysed. Stripping occurred 292 ± 39 degree-hours after the second dose of cPE and led to a mean spawning weight of 36.2 g, 10% spawning index, 241 oocytes/g of ova, 8222 oocytes/female and 23 oocytes/g of body weight. Stripped oocytes had a mean diameter of 2.33 mm and a mode at 2.375 mm, were weakly adhesive and coloration ranged from wine to brown. Under scanning electron microscopy, stripped oocytes exhibited a single funnel-shaped micropyle located at the animal pole and a zona radiata that measured 7.7 μm in thickness with eight pore canals/μm2. Oocyte morphology in Brycon nattereri is similar to that found in other species of the genus, except for the larger size and weaker adhesiveness. These findings provide essential information for a better understanding of the reproductive biology of B. nattereri and the establishment of conservation measures for this threatened species.

Nucleoli from two-cell embryos support the development of enucleolated germinal vesicle oocytes in the pig.

PubMed

Kyogoku, Hirohisa; Ogushi, Sugako; Miyano, Takashi

2012-11-01

Recent research has shown that nucleoli of oocytes at the germinal vesicle (GV) stage (GV nucleoli) are not necessary for oocyte maturation but are essential for early embryonic development. Nucleoli of 2-cell embryos (2-cell nucleoli) have morphology similar to that of nucleoli in oocytes at the GV stage. In this study, we examined the ability of 2-cell nucleoli to substitute for GV nucleoli in terms of supporting early embryonic development by nucleolus aspiration (enucleolation) and transfer into metaphase II (MII) oocytes or 2-cell embryos that were derived from enucleolated oocytes at the GV stage in the pig. When 2-cell embryos were centrifuged to move the lipid droplets to one side of the blastomere, multiple nucleoli in the nucleus fused into a single nucleolus. The nucleoli were then aspirated from the 2-cell embryos by micromanipulation. The injection of 2-cell nucleoli to GV enucleolated oocytes at the MII stage rescued the embryos from the early embryonic arrest, and the resulting oocytes developed to blastocysts. However, the injection of 2-cell and GV nucleoli to 2-cell embryos derived from GV enucleolated oocytes rarely restored the development to blastocysts. These results indicate that 2-cell nucleoli support early embryonic development as GV nucleoli and that the presence of nucleoli is essential for pig embryos before the 2-cell stage.

Elevated intracellular pH appears in aged oocytes and causes oocyte aneuploidy associated with the loss of cohesion in mice

PubMed Central

Cheng, Jin-Mei; Li, Jian; Tang, Ji-Xin; Chen, Su-Ren; Deng, Shou-Long; Jin, Cheng; Zhang, Yan; Wang, Xiu-Xia; Zhou, Chen-Xi; Liu, Yi-Xun

2016-01-01

ABSTRACT Increases in the aneuploidy rate caused by the deterioration of cohesion with increasing maternal age have been well documented. However, the molecular mechanism for the loss of cohesion in aged oocytes remains unknown. In this study, we found that intracellular pH (pHi) was elevated in aged oocytes, which might disturb the structure of the cohesin ring to induce aneuploidy. We observed for the first time that full-grown germinal vesicle (GV) oocytes displayed an increase in pHi with advancing age in CD1 mice. Furthermore, during the in vitro oocyte maturation process, the pHi was maintained at a high level, up to ∼7.6, in 12-month-old mice. Normal pHi is necessary to maintain protein localization and function. Thus, we put forward a hypothesis that the elevated oocyte pHi might be related to the loss of cohesion and the increased aneuploidy in aged mice. Through the in vitro alkalinization treatment of young oocytes, we observed that the increased pHi caused an increase in the aneuploidy rate and the sister inter-kinetochore (iKT) distance associated with the strength of cohesion and caused a decline in the cohesin subunit SMC3 protein level. Young oocytes with elevated pHi exhibited substantially the increase in chromosome misalignment. PMID:27472084

In-vitro maturation of germinal vesicle and metaphase I eggs prior to cryopreservation optimizes reproductive potential in patients undergoing fertility preservation.

PubMed

Lee, Joseph A; Sekhon, Lucky; Grunfeld, Lawrence; Copperman, Alan B

2014-06-01

To evaluate current and previous findings related to a timely implementation of in-vitro maturation (IVM) of germinal vesicle, metaphase I and metaphase II oocytes with an optimal cryopreservation to determine whether IVM should be attempted prior to (fresh IVM) or IVM after cryopreservation (postthaw IVM). Mitochondrion, chromatin and spindle formation in both groups were interpreted from referenced studies to establish best management of all oocytes. The postthaw survival of germinal vesicle, metaphase I, fresh IVM-metaphase II and control metaphase II oocytes did not differ significantly [83.3% (n=9), 86.7% (n=12), 83% (n=57) and 86% (n=68), respectively]. Overall, combined survival and maturation were significantly higher (P<0.05) in the fresh IVM group at 63.8% (44 of 69) compared with the postthaw IVM group at 33.3% (nine of 27). Conservation of retrieved immature oocytes after vaginal oocyte retrieval has become a major concern for patients, as they strive to maximize the reproductive viability of all oocytes obtained during treatment. Oocyte cryopreservation is important for patients at risk of ovarian cancer, elective fertility preservation and potentially for ovum donation. The superior maturation rate of germinal vesicle and metaphase I oocytes in the fresh IVM vs. postthaw groups provides strong impetus to mature oocytes to the metaphase II stage prior to cryopreservation.

Apoptosis in mammalian oocytes: a review.

PubMed

Tiwari, Meenakshi; Prasad, Shilpa; Tripathi, Anima; Pandey, Ashutosh N; Ali, Irfan; Singh, Arvind K; Shrivastav, Tulsidas G; Chaube, Shail K

2015-08-01

Apoptosis causes elimination of more than 99% of germ cells from cohort of ovary through follicular atresia. Less than 1% of germ cells, which are culminated in oocytes further undergo apoptosis during last phases of oogenesis and depletes ovarian reserve in most of the mammalian species including human. There are several players that induce apoptosis directly or indirectly in oocytes at various stages of meiotic cell cycle. Premature removal of encircling granulosa cells from immature oocytes, reduced levels of adenosine 3',5'-cyclic monophosphate and guanosine 3',5'-cyclic monophosphate, increased levels of calcium (Ca(2+)) and oxidants, sustained reduced level of maturation promoting factor, depletion of survival factors, nutrients and cell cycle proteins, reduced meiotic competency, increased levels of proapoptotic as well as apoptotic factors lead to oocyte apoptosis. The BH3-only proteins also act as key regulators of apoptosis in oocyte within the ovary. Both intrinsic (mitochondria-mediated) as well as extrinsic (cell surface death receptor-mediated) pathways are involved in oocyte apoptosis. BID, a BH3-only protein act as a bridge between both apoptotic pathways and its cleavage activates cell death machinery of both the pathways inside the follicular microenvironment. Oocyte apoptosis leads to the depletion of ovarian reserve that directly affects reproductive outcome of various mammals including human. In this review article, we highlight some of the important players and describe the pathways involved during oocyte apoptosis in mammals.

Xenopus laevis oocyte maturation is affected by metal chlorides.

PubMed

Marin, Matthieu; Slaby, Sylvain; Marchand, Guillaume; Demuynck, Sylvain; Friscourt, Noémie; Gelaude, Armance; Lemière, Sébastien; Bodart, Jean-François

2015-08-01

Few studies have been conducted using Xenopus laevis germ cells as oocytes, though these cells offer many advantages allowing both electrophysiological studies and morphological examination. Our aim was to investigate the effects of metal (cadmium, lead, cobalt and zinc) exposures using cell biology approaches. First, cell survival was evaluated with both phenotypical and electrophysiological approaches. Secondly, the effect of metals on oocyte maturation was assessed with morphological observations and electrophysiological recordings. From survival experiments, our results showed that metal chlorides did not affect cell morphology but strongly depolarized X. laevis oocyte resting potential. In addition, cadmium chloride was able to inhibit progesterone-induced oocyte maturation. By contrast, zinc, but also to a lesser extent cadmium, cobalt and lead, were able to enhance spontaneous oocyte maturation in the absence of progesterone stimulation. Finally, electrophysiological recordings revealed that some metal chlorides (lead, cadmium) exposures could disturb calcium signaling in X. laevis oocyte by modifying calcium-activated chloride currents. Our results demonstrated the high sensitivity of X. laevis oocytes toward exogenous metals such as lead and cadmium. In addition, the cellular events recorded might have a predictive value of effects occurring later on the ability of oocytes to be fertilized. Together, these results suggest a potential use of this cellular lab model as a tool for ecotoxicological assessment of contaminated fresh waters. Copyright © 2015 Elsevier Ltd. All rights reserved.

Supplementation with CTGF, SDF1, NGF, and HGF promotes ovine in vitro oocyte maturation and early embryo development.

PubMed

Wang, D H; Ren, J; Zhou, C J; Han, Z; Wang, L; Liang, C G

2018-05-17

The strategies for improving the in vitro maturation (IVM) of domestic animal oocytes focus on promoting nuclear and cytoplasmic maturation. The identification of paracrine factors and their supplementation in the culture medium represent effective approaches for oocyte maturation and embryo development. This study investigated the effects of paracrine factor supplementation including connective tissue growth factor (CTGF), nerve growth factor (NGF), hepatocyte growth factor (HGF), and stromal derived factor 1 (SDF1) on ovine oocytes and early parthenogenetic embryos using an in vitro culture system. First, we identified the optimal concentrations of CTGF (30 ng/mL), SDF1 (10 ng/mL), NGF (3 ng/mL), and HGF (100 ng/mL) for promoting oocyte maturation, which combined, induced nuclear maturation in 94.19% of oocytes. This combination also promoted cumulus cell expansion and inhibited oocyte/cumulus apoptosis, while enabling a larger proportion (33.04%) of embryos to develop into blastocysts than in the controls and prevented embryo apoptosis. These novel findings demonstrate that the paracrine factors CTGF, SDF1, NGF, and HGF facilitate ovine oocyte and early parthenogenetic embryo development in vitro. Thus, supplementation with these factors may help optimize the IVM of ovine oocytes and early parthenogenetic embryo development strategies. Copyright © 2018 Elsevier Inc. All rights reserved.

Protective effects of ethanol extracts of Artemisia asiatica Nakai ex Pamp. on ageing-induced deterioration in mouse oocyte quality.

PubMed

Jeon, Hyuk-Joon; You, Seung Yeop; Kim, Dong Hyun; Jeon, Hong Bae; Oh, Jeong Su

2017-08-01

Following ovulation, oocytes undergo a time-dependent deterioration in quality referred to as post-ovulatory ageing. Although various factors influence the post-ovulatory ageing of oocytes, oxidative stress is a key factor involved in deterioration of oocyte quality. Artemisia asiatica Nakai ex Pamp. has been widely used in East Asia as a food ingredient and traditional medicine for the treatment of inflammation, cancer, and microbial infections. Recent studies have shown that A. asiatica exhibits antioxidative effects. In this study, we investigated whether A. asiatica has the potential to attenuate deterioration in oocyte quality during post-ovulatory ageing. Freshly ovulated mouse oocytes were cultured with 0, 50, 100 or 200 μg/ml ethanol extracts of A. asiatica Nakai ex Pamp. After culture for up to 24 h, various ageing-induced oocyte abnormalities, including morphological changes, reactive oxygen species (ROS) accumulation, apoptosis, chromosome and spindle defects, and mitochondrial aggregation were determined. Treatment of oocytes with A. asiatica extracts reduced ageing-induced morphological changes. Moreover, A. asiatica extracts decreased ROS generation and the onset of apoptosis by preventing elevation of the Bax/Bcl-2 expression ratio during post-ovulatory ageing. Furthermore, A. asiatica extracts attenuated the ageing-induced abnormalities including spindle defects, chromosome misalignment and mitochondrial aggregation. Our results demonstrate that A. asiatica can relieve deterioration in oocyte quality and delay the onset of apoptosis during post-ovulatory ageing.

Prooxidant Effects of Verbascoside, a Bioactive Compound from Olive Oil Mill Wastewater, on In Vitro Developmental Potential of Ovine Prepubertal Oocytes and Bioenergetic/Oxidative Stress Parameters of Fresh and Vitrified Oocytes

PubMed Central

Dell'Aquila, M. E.; Bogliolo, L.; Russo, R.; Martino, N. A.; Filioli Uranio, M.; Ariu, F.; Amati, F.; Sardanelli, A. M.; Linsalata, V.; Ferruzzi, M. G.; Cardinali, A.; Minervini, F.

2014-01-01

Verbascoside (VB) is a bioactive polyphenol from olive oil mill wastewater with known antioxidant activity. Oxidative stress is an emerging problem in assisted reproductive technology (ART). Juvenile ART is a promising topic because, in farm animals, it reduces the generation gap and, in human reproductive medicine, it helps to overcome premature ovarian failure. The aim of this study was to test the effects of VB on the developmental competence of ovine prepubertal oocytes and the bioenergetic/oxidative stress status of fresh and vitrified oocytes. In fresh oocytes, VB exerted prooxidant short-term effects, that is, catalase activity increase and uncoupled increases of mitochondria and reactive oxygen species (ROS) fluorescence signals, and long-term effects, that is, reduced blastocyst formation rate. In vitrified oocytes, VB increased ROS levels. Prooxidant VB effects in ovine prepubertal oocytes could be related to higher VB accumulation, which was found as almost one thousand times higher than that reported in other cell systems in previous studies. Also, long exposure times of oocytes to VB, throughout the duration of in vitro maturation culture, may have contributed to significant increase of oocyte oxidation. Further studies are needed to identify lower concentrations and/or shorter exposure times to figure out VB antioxidant effects in juvenile ARTs. PMID:24719893

SKAP2 regulates Arp2/3 complex for actin-mediated asymmetric cytokinesis by interacting with WAVE2 in mouse oocytes

PubMed Central

Xu, Bai-Hui; Liu, Yu; Wang, Ya-Long; Chen, Ming-Huang; Xu, Lin; Liao, Bao-Qiong; Lui, Rui; Li, Fei-Ping; Lin, Yan-Hong; Fu, Xian-Pei; Fu, Bin-Bin; Hong, Zi-Wei; Qi, Zhong-Quan

2017-01-01

ABSTRACT SKAP2 (Src kinase-associated phosphoprotein 2), a substrate of Src family kinases, has been suggested to be involved in actin-mediated cellular processes. However, little is known about its role in mouse oocyte maturation. In this study, we thus investigated the expression, localization, and functions of SKAP2 during mouse oocyte asymmetric division. SKAP2 protein expression was detected at all developmental stages in mouse oocytes. Immunofluorescent staining showed that SKAP2 was mainly distributed at the cortex of the oocytes during maturation. Treatment with cytochalasin B in oocytes confirmed that SKAP2 was co-localized with actin. Depletion of SKAP2 by injection with specific short interfering RNA caused failure of spindle migration, polar body extrusion, and cytokinesis defects. Meanwhile, the staining of actin filaments at the oocyte membrane and in the cytoplasm was significantly reduced after these treatments. SKAP2 depletion also disrupted actin cap and cortical granule-free domain formation, and arrested a large proportion of oocytes at the telophase stage. Moreover, Arp2/3 complex and WAVE2 expression was decreased after the depletion of SKAP2 activity. Our results indicate that SKAP2 regulates the Arp2/3 complex and is essential for actin-mediated asymmetric cytokinesis by interacting with WAVE2 in mouse oocytes. PMID:28933599

Extending prematuration with cAMP modulators enhances the cumulus contribution to oocyte antioxidant defence and oocyte quality via gap junctions.

PubMed

Li, H J; Sutton-McDowall, M L; Wang, X; Sugimura, S; Thompson, J G; Gilchrist, R B

2016-04-01

Can bovine oocyte antioxidant defence and oocyte quality be improved by extending the duration of pre-in vitro maturation (IVM) with cyclic adenosine mono-phosphate (cAMP) modulators? Lengthening the duration of cAMP-modulated pre-IVM elevates intra-oocyte reduced glutathione (GSH) content and reduces hydrogen peroxide (H2O2) via increased cumulus cell-oocyte gap-junctional communication (GJC), associated with an improvement in subsequent embryo development and quality. Oocytes are susceptible to oxidative stress and the oocyte's most important antioxidant glutathione is supplied, at least in part, by cumulus cells. A temporary inhibition of spontaneous meiotic resumption in oocytes can be achieved by preventing a fall in cAMP, and cyclic AMP-modulated pre-IVM maintains cumulus-oocyte GJC and improves subsequent embryo development. This study consisted of a series of 10 experiments using bovine oocytes in vitro, each with multiple replicates. A range of pre-IVM durations were examined as the key study treatments which were compared with a control. The study was designed to examine if one of the oocyte's major antioxidant defences can be enhanced by pre-IVM with cAMP modulators, and to examine the contribution of cumulus-oocyte GJC on these processes. Immature bovine cumulus-oocyte complexes were treated in vitro without (control) or with the cAMP modulators; 100 µM forskolin (FSK) and 500 µM 3-isobutyl-1-methyxanthine (IBMX), for 0, 2, 4 or 6 h (pre-IVM phase) prior to IVM. Oocyte developmental competence was assessed by embryo development and quality post-IVM/IVF. Cumulus-oocyte GJC, intra-oocyte GSH and H2O2 were quantified at various time points during pre-IVM and IVM, in the presence and the absence of functional inhibitors: carbenoxolone (CBX) to block GJC and buthionine sulfoximide (BSO) to inhibit glutathione synthesis. Pre-IVM with FSK + IBMX increased subsequent blastocyst formation rate and quality compared with standard IVM (P < 0.05), regardless of pre-IVM duration. The final blastocyst yields (proportion of blastocysts/immature oocyte) were 26.3% for the control, compared with 39.2, 35.2 and 34.2%, for the 2, 4 and 6 h pre-IVM FSK + IBMX treatments, respectively. In contrast to standard IVM (control), pre-IVM with cAMP modulators maintained open gap junctions between cumulus cells and oocytes for the duration (6 h) of pre-IVM examined, and persisted for a further 8 h in the IVM phase. Cyclic AMP-modulated pre-IVM increased intra-oocyte GSH levels at the completion of both pre-IVM and IVM, in a pre-IVM duration-dependent manner (P < 0.05), which was ablated when GJC was blocked using CBX (P < 0.05). By 4 h of pre-IVM treatment with cAMP modulators, oocyte H2O2 levels were reduced compared the control (P < 0.05), although this beneficial effect was lost when oocytes were co-treated with BSO. Inhibiting glutathione synthesis with BSO during pre-IVM ablated any positive benefits of cAMP-mediated pre-IVM on oocyte developmental competence (P < 0.01). It is unclear if the improvement in oocyte antioxidant defence and developmental competence reported here is due to direct transfer of total and/or reduced glutathione from cumulus cells to the oocyte via gap junctions, or whether a GSH synthesis signal and/or amino acid substrates are supplied to the oocyte via gap junctions. Embryo transfer experiments are required to determine if the cAMP-mediated improvement in blastocyst rates leads to improved live birth rates. IVM offers significant benefits to infertile and cancer patients and has the potential to significantly alter ART practice, if IVM efficiency in embryo production could be improved closer to that of conventional IVF (using ovarian hyperstimulation). Pre-IVM with cAMP modulators is a simple and reliable means to improve IVM outcomes. This work was supported by grants and fellowships from the National Health and Medical Research Council of Australia (1007551, 627007, 1008137, 1023210) and by scholarships from the Chinese Scholarship Council (CSC) awarded to H.J.L. and the Japanese Society for the Promotion of Science Postdoctoral Fellowship for Research Abroad awarded to S.S. The Fluoview FV10i confocal microscope was purchased as part of the Sensing Technologies for Advanced Reproductive Research (STARR) facility, funded by the South Australian Premier's Science and Research Fund. We acknowledge partial support from the Australian Research Council Centre of Excellence for Nanoscale BioPhotonics (CE140100003). We declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported. © The Author 2016. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Functional enucleation of porcine oocytes for somatic cell nuclear transfer using femtosecond laser pulses

NASA Astrophysics Data System (ADS)

Kuetemeyer, K.; Lucas-Hahn, A.; Petersen, B.; Hassel, P.; Lemme, E.; Niemann, H.; Heisterkamp, A.

2010-02-01

Cloning of several mammalian species has been achieved by somatic cell nuclear transfer over the last decade. However, this method still results in very low efficiencies originating from biological and technical aspects. The highly-invasive mechanical enucleation belongs to the technical aspects and requires considerable micromanipulation skill. In this paper, we present a novel non-invasive method for combined oocyte imaging and automated functional enucleation using femtosecond (fs) laser pulses. After three-dimensional imaging of Hoechst-labeled porcine oocytes by multiphoton microscopy, our self-developed software automatically determined the metaphase plate position and shape. Subsequent irradiation of this volume with the very same laser at higher pulse energies in the low-density-plasma regime was used for metaphase plate ablation. We show that functional fs laser-based enucleation of porcine oocytes completely inhibited further embryonic development while maintaining intact oocyte morphology. In contrast, non-irradiated oocytes were able to develop to the blastocyst stage without significant differences to control oocytes. Our results indicate that fs laser systems offer great potential for oocyte imaging and enucleation as a fast, easy to use and reliable tool which may improve the efficiency of somatic cell clone production.

The effect of glucocorticoids on ERK-1/2 phosphorylation during maturation of lamb oocytes and their subsequent fertilization and cleavage ability in vitro.

PubMed

González, Raquel; Ruiz-León, Yolanda; Gomendio, Montserrat; Roldan, Eduardo R S

2010-04-01

High levels of glucocorticoids may alter reproduction, but little is known about their direct actions on oocyte maturation, fertilization and subsequent development. Earlier work suggested negative effects of cortisol or dexamethasone on oocyte maturation but differences were noted between animal models. Both glucocorticoids reduce the p34(cdc2)-cyclin B1 complex but it is unknown if other signaling pathways important for meiosis progression are affected. In this study, using sheep oocytes as a model system, we assessed in vitro the effects of increasing concentration of glucocorticoids (0-250 microM) on oocyte maturation and underlying changes in the MAP kinase pathway, and the ability of oocytes to undergo fertilization and embryo development. Cortisol decreased oocyte maturation but only at the highest concentration, whereas dexamethasone had no effect. Fertilization and cleavage were not affected. On the other hand, both cortisol and dexamethasone inhibited ERK-1/2 activation in a concentration-dependent manner. It thus seems that oocytes can overcome deleterious effects of glucocorticoids during maturation despite the decrease in ERK-1/2 activity, but repercussions in vivo should be further explored. Copyright 2009 Elsevier Inc. All rights reserved.

New technique for mouse oocyte injection via a modified holding pipette.

PubMed

Lyu, Q F; Deng, L; Xue, S G; Cao, S F; Liu, X Y; Jin, W; Wu, L Q; Kuang, Y P

2010-11-01

To improve mouse oocyte survival from intracytoplasmic sperm injection, the sharp tip of the injection pipette has been modified to have a flat end. Here, for the same goal but for a more convenient manipulation, a sharp injection pipette was kept whereas the holding pipette was modified to have a trumpet-shaped opening, which allows deeper injection into the oocyte as it is held. Mouse oocyte injection with mouse and human spermatozoa was performed at 37°C. For the injection of mouse oocyte with mouse sperm head, a significantly higher survival rate (83%) was achieved by utilizing the modified holding pipette than the conventional one (21%; P<0.001) and the fertilization rates were normal and comparable for both methods (82% versus 81%). A superior survival rate (82%) and acceptable normal fertilization rate (71%) were also achieved by utilizing the modified holding pipette for interspecies ICSI (injecting mouse oocyte with human spermatozoon). Taken together, by utilizing a holding pipette with a trumpet-shaped opening, acceptable rates of mouse oocyte survival and fertilization can be achieved using a sharp injection pipette under conditions usual for human oocyte injection. Copyright © 2010 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

PP2A regulates kinetochore-microtubule attachment during meiosis I in oocyte.

PubMed

Tang, An; Shi, Peiliang; Song, Anying; Zou, Dayuan; Zhou, Yue; Gu, Pengyu; Huang, Zan; Wang, Qinghua; Lin, Zhaoyu; Gao, Xiang

2016-06-02

Studies using in vitro cultured oocytes have indicated that the protein phosphatase 2A (PP2A), a major serine/threonine protein phosphatase, participates in multiple steps of meiosis. Details of oocyte maturation regulation by PP2A remain unclear and an in vivo model can provide more convincing information. Here, we inactivated PP2A by mutating genes encoding for its catalytic subunits (PP2Acs) in mouse oocytes. We found that eliminating both PP2Acs caused female infertility. Oocytes lacking PP2Acs failed to complete 1(st) meiotic division due to chromosome misalignment and abnormal spindle assembly. In mitosis, PP2A counteracts Aurora kinase B/C (AurkB/C) to facilitate correct kinetochore-microtubule (KT-MT) attachment. In meiosis I in oocyte, we found that PP2Ac deficiency destabilized KT-MT attachments. Chemical inhibition of AurkB/C in PP2Ac-null oocytes partly restored the formation of lateral/merotelic KT-MT attachments but not correct KT-MT attachments. Taken together, our findings demonstrate that PP2Acs are essential for chromosome alignments and regulate the formation of correct KT-MT attachments in meiosis I in oocytes.

Confirmation of ovarian homogeneity in post-vitellogenic cultured white sturgeon, Acipenser transmontanus.

PubMed

Talbott, Mariah J; Servid, Sarah A; Cavinato, Anna G; Van Eenennaam, Joel P; Doroshov, Serge I; Struffenegger, Peter; Webb, Molly A H

2014-02-01

Assessing stage of oocyte maturity in female sturgeon by calculating oocyte polarization index (PI) is a necessary tool for both conservation propagation managers and caviar producers to know when to hormonally induce spawning. We tested the assumption that sampling ovarian follicles from one section of one ovary is sufficient for calculating an oocyte PI representative of oocyte maturity for an individual animal. Short-wavelength near-infrared spectroscopy (SW-NIR) scans were performed on three positions per ovary for five fish prior to caviar harvest. Samples of ovarian follicles were subsequently taken from the exact location of the SW-NIR scans for calculation of oocyte PI and follicle diameter. Oocyte PI was statistically different though not biologically relevant within an ovary and between ovaries in four of five fish. Follicle diameter was statistically different but not biologically relevant within an ovary in three of five fish. There were no differences in follicle diameter between ovaries. No statistical differences were observed between SW-NIR spectra collected at different locations within an ovary or between ovaries. These results emphasize the importance of utilizing both oocyte PI measurement and progesterone-induced oocyte maturation assays while deciding when to hormonally induce spawning in sturgeon females.

Wolbachia Infect Ovaries in the Course of Their Maturation: Last Minute Passengers and Priority Travellers?

PubMed Central

Genty, Lise-Marie; Bouchon, Didier; Raimond, Maryline; Bertaux, Joanne

2014-01-01

Wolbachia are widespread endosymbiotic bacteria of arthropods and nematodes. Studies on such models suggest that Wolbachia's remarkable aptitude to infect offspring may rely on a re-infection of ovaries from somatic tissues instead of direct cellular segregation between oogonia and oocytes. In the terrestrial isopod Armadillidium vulgare, Wolbachia are vertically transmitted to the host offspring, even though ovary cells are cyclically renewed. Using Fluorescence in situ hybridization (FISH), we showed that the proportion of infected oocytes increased in the course of ovary and oocyte maturation, starting with 31.5% of infected oocytes only. At the end of ovary maturation, this proportion reached 87.6% for the most mature oocytes, which is close to the known transmission rate to offspring. This enrichment can be explained by a secondary acquisition of the bacteria by oocytes (Wolbachia can be seen as last minute passengers) and/or by a preferential selection of oocytes infected with Wolbachia (as priority travellers). PMID:24722673

Biotin-deficient diet induces chromosome misalignment and spindle defects in mouse oocytes.

PubMed

Tsuji, Ai; Nakamura, Toshinobu; Shibata, Katsumi

2015-01-01

Increased abnormal oocytes due to meiotic chromosome misalignment and spindle defects lead to elevated rates of infertility, miscarriage, and trisomic conceptions. Here, we investigated the effect of biotin deficiency on oocyte quality. Three-week-old female ICR mice were fed a biotin-deficient or control diet (0, 0.004 g biotin/kg diet) for 21 days. On day 22, these mouse oocytes were analyzed by immunofluorescence. Due to biotin, undernutrition increased the frequency of abnormal oocytes (the biotin deficient vs. control: 40 vs. 16%). Next, the remaining mice in the biotin-deficient group were fed a control or biotin-deficient diet from day 22 to 42. Although biotin nutritional status in the recovery group was restored, the frequency of abnormal oocytes in the recovery group was still higher than that in the control group (48 vs. 18%). Our results indicate that steady, sufficient biotin intake is required for the production of high-quality oocytes in mice.

Effect of Heat Stress on Reproduction in Dairy Cows: Insights into the Cellular and Molecular Responses of the Oocyte.

PubMed

Roth, Zvi

2017-02-08

Among the components of the female reproductive tract, the ovarian pool of follicles and their enclosed oocytes are highly sensitive to hyperthermia. Heat-induced alterations in small antral follicles can be expressed later as compromised maturation and developmental capacity of the ovulating oocyte. This review summarizes the most up-to-date information on the effects of heat stress on the oocyte with an emphasis on unclear points and open questions, some of which might involve new research directions, for instance, whether preantral follicles are heat resistant. The review focuses on the follicle-enclosed oocytes, provides new insights into the cellular and molecular responses of the oocyte to elevated temperature, points out the role of the follicle microenvironment, and discusses some mechanisms that might underlie oocyte impairment. Mechanisms include nuclear and cytoplasmic maturation, mitochondrial function, apoptotic pathways, and oxidative stress. Understanding the mechanism by which heat stress compromises fertility might enable development of new strategies to mitigate its effects.

Oocyte cryopreservation: a feasible fertility preservation option for reproductive age cancer survivors

PubMed Central

Labella, Patty Ann; Grifo, James; Knopman, Jaime M.

2010-01-01

Purpose To compare oocyte cryopreservation cycles performed in cancer patients to those of infertile women. Methods Cancer patients referred for fertility preservation underwent counseling in compliance with the ASRM; those electing oocyte cryopreservation were included. Ovarian stimulation was achieved with injectable gonadotropins and freezing was performed using slow-cooling and vitrification methods. Results Fifty cancer patients (mean age 31 y) underwent oocyte cryopreservation; adequate ovarian stimulation was achieved in 10 ± 0.3 days. The outcome from these cycles included a mean peak estradiol of 2,376 pg/ml and an average of 19 oocytes retrieved (15 mature oocytes were cryopreserved/cycle). All patients tolerated ovarian hyperstimulation. There were no significant differences noted between cryopreservation cycles performed in cancer patients and in women without malignancy. Conclusions Oocyte cryopreservation appears to be a feasible fertility preservation method for reproductive-age women diagnosed with cancer. This modality is not only effective but also, providing a multidiscipline effort, can be completed in timely fashion. PMID:20480389

Skewed segregation of the mtDNA nt 8993 (T-->G) mutation in human oocytes.

PubMed Central

Blok, R B; Gook, D A; Thorburn, D R; Dahl, H H

1997-01-01

Rapid changes in mtDNA variants between generations have led to the bottleneck theory, which proposes a dramatic reduction in mtDNA numbers during early oogenesis. We studied oocytes from a woman with heteroplasmic expression of the mtDNA nt 8993 (T-->G) mutation. Of seven oocytes analyzed, one showed no evidence of the mutation, and the remaining six had a mutant load > 95%. This skewed expression of the mutation in oocytes is not compatible with the conventional bottleneck theory. A possible explanation is that, during amplification of mtDNA in the developing oocyte, mtDNA from one mitochondrion is preferentially amplified. Thus, subsequent mature oocytes may contain predominantly wild-type or mutant mitochondrial genomes. Images Figure 2 Figure 3 PMID:9199572

In vitro Maturation of Oocytes in High Altitude Women with Polycystic Ovaries.

PubMed

Tominaga, Luis A Vargas; Cáceres, Ricardo E Pella; Lechuga, Jose A Vargas; Durán, Livia S Bartolo; Vargas, Mariela Serrano

2015-05-01

Determine the effectiveness of in vitro maturation of oocytes in the infertility treatment in high altitude women with polycystic ovaries. descriptive and retrospective study. Women with polycystic ovaries and infertility. there were 11 women from locations above 7,546 feet above sea level with polycystic ovaries and infertility in which were performed in vitro maturation of oocytes, followed by intracytoplasmic sperm injection, culture and embryo vitrification. After that, the endometrium was prepared and the embryos were thawed and transferred. Main results mesurements: oocytes maturation, fertilization, clinical pregnancy and implantation rates. Oocytes maturation rate was 86.1%; fertilization rate 90.3%; clinical pregnancy rate 36.4% and implantation rate 17.4%. In vitro maturation of oocytes is an effective technique in the infertility treatment of high altitude women with polycystic ovaries.

What threshold values of antral follicle count and serum AMH levels should be considered for oocyte cryopreservation after in vitro maturation?

PubMed

Sonigo, C; Simon, C; Boubaya, M; Benoit, A; Sifer, C; Sermondade, N; Grynberg, M

2016-07-01

What threshold values of ultrasonographic antral follicle count (AFC) and serum anti-Müllerian hormone (AMH) levels should be considered for ensuring the cryopreservation of sufficient number of in vitro matured (IVM) oocytes, in cancer patients seeking fertility preservation (FP)? AFC and serum AMH values >20 follicles and 3.7 ng/ml, respectively, are required for obtaining at least 10 IVM oocytes for cryopreservation. IVM of cumulus oocyte complexes (COCs) followed by oocyte cryopreservation has emerged recently as an option for urgent FP. Recent data have reported that, in healthy patients, 8-20 cryopreserved oocytes after ovarian stimulation would maximize the chance of obtaining a live birth. Although both AFC and AMH have been reported as predictive factors of IVM success in infertile patients with polycystic ovary syndrome (PCOS), there is a dramatic lack of data regarding the values of these parameters in oncological patients as candidates for FP. From January 2009 to April 2015, we prospectively studied 340 cancer patients, aged 18-41 years, as candidates for oocyte cryopreservation following IVM. All patients had AFC and AMH measurements, 48-72 h before oocyte retrieval, regardless of the phase of the cycle. COCs were recovered under ultrasound guidance 36 h after hCG priming. Logistic regression allowed the determination of threshold values of AFC and AMH, for obtaining at least 8, 10 or 15 matures oocytes frozen after the IVM procedure. Similar analyses were performed for a final number of mature oocytes ≤2. Among the 340 cancer patients included, 300 were diagnosed with breast cancers, 14 had hematological malignancies and 26 underwent the procedure for others indications. Overall, the mean age of the population was 31.8 ± 4.5 years. Mean AFC and serum AMH levels were 21.7 ± 13.3 follicles and 4.4 ± 3.8 ng/ml, respectively. IVM was performed in equal proportions during the follicular or luteal phase of the cycle (49 and 51%, respectively). Statistical analysis showed that AFC and AMH values above 28 follicles and 3.9 ng/ml, 20 follicles and 3.7 ng/ml and 19 follicles and 3.5 ng/ml are required, respectively, for obtaining at least 15, 10 or 8 frozen IVM oocytes with a sensitivity ranging from 0.82 to 0.90. On the contrary, ≤2 IVM oocytes were cryopreserved when AFC and AMH were <19 follicles and 3.0 ng/ml, respectively. Although the potential of cryopreserved IVM oocytes from cancer patients remains unknown, data obtained from infertile PCOS women have shown a dramatically reduced competence of these oocytes when compared with that of oocytes recovered after ovarian stimulation. As a consequence, the optimal number of IVM oocytes frozen in candidates for FP is currently unpredictable. Cryopreservation of oocytes after IVM should be considered in the FP strategy when ovarian stimulation is unfeasible, in particular when markers of the follicular ovarian status are at a relatively high range. Further investigation is needed to objectively assess the real potential of these IVM oocytes after cryopreservation. Therefore, even when a good COCs yield is expected, we should systematically encourage IVM in combination with ovarian tissue cryopreservation. No external funding was obtained for the present study. The authors have no conflict of interest to declare. Not applicable. © The Author 2016. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Ultrasonographic-guided retrieval of cumulus oocyte complexes after super-stimulation in dromedary camel (Camelus dromedarius).

PubMed

Wani, N A; Skidmore, J A

2010-08-01

In Experiment 1, studies were conducted to apply the transvaginal ultrasound guided ovum pick-up (OPU) technique in dromedary camels after their ovarian super-stimulation and in vivo oocyte maturation. In Experiment 2, the developmental potential of two commonly used oocyte types, i.e., in vivo matured oocytes collected by OPU and abattoir derived in vitro-matured oocytes was compared after their chemical activation. In Experiment 3, developmental competence of oocytes collected from super-stimulated camels by OPU, matured either in vivo or in vitro, was compared after their chemical activation. Mature female dromedary camels super-stimulated with a combination of eCG and pFSH were given an injection of 20 microg of the GnRH analogue, buserelin 24, 26, or 28 h before the scheduled OPU. For collection of cumulus oocyte complexes (COCs) the transducer was guided through the vulva into the cranial most portion of the vagina and 17-gauge, 55 cm single-lumen needle was placed in the needle guide of the ultrasound probe and advanced through the vaginal fornix and into the follicle. Follicular fluid was aspirated using a regulated vacuum pump into tubes containing embryo-flushing media. Aspirates were searched for COCs using a stereomicroscope, and they were then denuded of cumulus cells by hyaluronidase and repeated pipetting. The oocytes were classified as mature (with a visible polar body), immature (with no visible polar body), activated (with divided or fragmented ooplasm) and others (degenerated and abnormal). Overall an average of 12.12 +/- 7.9 COCs were aspirated per animal with an oocyte recovery rate from the aspirated follicles of about 77%. The majority (> 90%) of the collected COCs by OPU were with loose and expanded cumulus cells. The proportion of matured oocytes obtained at 28-29 h (91.2 +/- 4.1) and 26-27 h (82.1 +/- 3.4) were higher (P < 0.005) when compared with those obtained at 24-25 h (40.4 +/- 16.3) after GnRH administration. In Experiment 2, a higher proportion (P < 0.05) of in vivo matured oocytes cleaved (84.6 +/- 2.1 vs. 60.9 +/- 6.6) and developed to blastocyst stages (52.4 +/- 4.1 vs. 30.5 +/- 3.3) when compared with in vitro matured oocytes collected from slaughterhouse ovaries. In Experiment 3, no difference was observed between the developmental competences of oocytes, collected from super stimulated camels, matured in vitro with those collected after their in vivo maturation. In conclusion, about 80-90% mature oocytes can be collected by ultrasound guided transvaginal ovum pick-up from super-stimulated dromedary camels 26-28 h after GnRH administration. The developmental response, to chemical activation, of in vivo matured oocytes collected by ultrasound guided transvaginal OPU is better than in vitro matured oocytes obtained from slaughterhouse ovaries. However, no difference was observed in the developmental competence of oocytes collected by OPU whether they were matured in vivo or in vitro. Copyright 2010 Elsevier Inc. All rights reserved.

Fourier analysis of mitochondrial distribution in oocytes

NASA Astrophysics Data System (ADS)

Hollmann, Joseph L.; Brooks, Dana H.; Newmark, Judith A.; Warner, Carol M.; DiMarzio, Charles A.

2011-03-01

This paper describes a novel approach to quantifying mitochondrial patterns which are typically described using the qualitative terms "diffuse" "aggregated" and are potentially key indicators for an oocyte's health and survival potential post-implantation. An oocyte was isolated in a confocal image and a coarse grid was superimposed upon it. The spatial spectrum was calculated and an aggregation factor was generated. A classifier for healthy cells was developed and verified. The aggregation factor showed a clear distinction between the healthy and unhealthy oocytes. The ultimate goal is to screen oocytes for viability preimplantation, thus improving the outcome of in vitro fertilization (IVF) treatments.

Melatonin accelerates maturation inducing hormone (MIH): induced oocyte maturation in carps.

PubMed

Chattoraj, Asamanja; Bhattacharyya, Sharmistha; Basu, Dipanjan; Bhattacharya, Shelley; Bhattacharya, Samir; Maitra, Saumen Kumar

2005-02-01

The present communication is an attempt to demonstrate the influence of melatonin on the action of maturation inducing hormone (MIH) on the maturation of oocytes in carps. The oocytes from gravid female major carp Labeo rohita were isolated and incubated separately in Medium 199 containing (a) only MIH (1 microg/ml), (b) only melatonin (at concentrations of 50, 100 or 500 pg/ml), and (c) both melatonin and MIH, but at different time intervals. In the latter group, melatonin was added to the incubating medium either (i) 4 h before addition of MIH, (ii) 2 h before addition of MIH, (iii) co-administered with MIH (0 h interval) or (iv) 2 h after addition of MIH. In each case, oocytes were further incubated for 4, 8, 12 or 16 h post- administration of MIH, and the effects of treatment on oocyte maturation were evaluated by considering the rate (%) of germinal vesicle breakdown (GVBD). Incubation of oocytes in a medium containing only melatonin did not result in GVBD of any oocyte. Nearly all the oocytes underwent GVBD when incubated with MIH for 16 h. Administration of melatonin along with MIH (at 0 h interval) or 2 h after addition of MIH did not result in any significant change in the rate of GVBD compared to that in a medium containing only MIH. However, it was quite interesting to observe that incubation of oocytes with melatonin especially 4 h prior to addition of MIH in the medium, led to an accelerated rate of GVBD in the oocytes. Experiments with the oocytes of another major carp Cyprinus carpio following an identical schedule depicted similar results except a difference in the optimum melatonin dose. In L. rohita, 50 pg/ml melatonin had maximum acceleratory effect on MIH-induced GVBD of oocytes, while it was 100 pg/ml in C. carpio. Further study revealed that pre-incubation with melatonin accelerates the action of MIH on the formation of a complex of two proteins (MPF), a regulatory component called cyclin B and the catalytic component protein kinase known as cyclin-dependent kinase, Cdk1. Densitometric analysis of the immunoblot data collected from the melatonin pre-treated MIH incubated oocytes showed that cyclin B level continued to increase even after 4 h of incubation, and reached the peak after 12 h. Moreover, determination of H1 kinase activity as an indicator of MPF activity in oocytes revealed that melatonin pre-incubation considerably increased MIH stimulation of histone H1 phosphorylation as compared to MIH alone. Thus, the present study demonstrates for the first time that prior incubation with melatonin accelerates the action of MIH on carp oocyte maturation.

Cilostamide and forskolin treatment during pre-IVM improves preimplantation development of cloned embryos by influencing meiotic progression and gap junction communication in pigs.

PubMed

Park, Bola; Lee, Hanna; Lee, Yongjin; Elahi, Fazle; Lee, Joohyeong; Lee, Seung Tae; Park, Choon-Keun; Hyun, Sang-Hwan; Lee, Eunsong

2016-08-01

This study was conducted to evaluate the effects of treatment with the cAMP modulators cilostamide and/or forskolin during pre-IVM culture on meiotic progression, gap junction communication, intraoocyte cAMP level and glutathione content, embryonic development after parthenogenesis, and somatic cell nuclear transfer in pigs. Cumulus-oocyte complexes were cultured for 24 hours in unsupplemented medium or media containing 20 μM cilostamide and/or 50 μM forskolin. After pre-IVM, oocytes were cultured for 41 to 44 hours in a standard IVM medium to induce oocyte maturation. When the nuclear status of oocytes was examined after pre-IVM for 24 hours, a higher (P < 0.01) proportion of oocytes treated with forskolin (85.5%) and cilostamide + forskolin (92.6%) remained at the germinal vesicle stage compared with untreated (20.6%) and cilostamide-treated oocytes (54.7%). cAMP level in pre-IVM oocytes was significantly increased by combined treatment with cilostamide + forskolin (21.38 fmol/oocyte) relative to the no pre-IVM control, no treatment, cilostamide, and forskolin groups (2.85, 1.88, 1.74, and 8.95 fmol/oocyte, respectively). Forskolin with or without cilostamide significantly maintained open-gap junction communication relative to no treatment. Blastocyst formation in parthenogenesis was significantly (P < 0.01) improved by forskolin (65.3%) relative to other treatments (28.3% to 48.1%). Supplementation of pre-IVM with dibutyryl cAMP showed similar blastocyst formation as forskolin treatment (61.1% and 61.0%, respectively). In somatic cell nuclear transfer, simultaneous treatment with cilostamide + forskolin significantly (P < 0.05) increased embryonic development to the blastocyst stage (42.9%) relative to the no pre-IVM, control, and cilostamide groups (32.3, 28.6, and 32.8%, respectively). The glutathione contents in pre-IVM oocytes were increased by no treatment, forskolin, and cilostamide + forskolin (1.38, 1.39, and 1.27 pixels/oocyte, respectively) compared with no pre-IVM and cilostamide (1.00 and 0.99 pixels/oocyte, respectively; P < 0.05). Our results reported that the meiotic progression of immature pig oocytes could be reversibly attenuated by cAMP, whereas treatment with cilostamide and forskolin during pre-IVM had positive effects on developmental competence of oocytes in pigs, probably by improving cytoplasmic maturation. Copyright © 2016 Elsevier Inc. All rights reserved.

Effects of Different Maturation Systems on Bovine Oocyte Quality, Plasma Membrane Phospholipid Composition and Resistance to Vitrification and Warming.

PubMed

Sprícigo, José F W; Diógenes, Mateus N; Leme, Ligiane O; Guimarães, Ana L; Muterlle, Carolle V; Silva, Bianca Damiani Marques; Solà-Oriol, David; Pivato, Ivo; Silva, Luciano Paulino; Dode, Margot A N

2015-01-01

The objective of this study was to evaluate the effects of different maturation systems on oocyte resistance after vitrification and on the phospholipid profile of the oocyte plasma membrane (PM). Four different maturation systems were tested: 1) in vitro maturation using immature oocytes aspirated from slaughterhouse ovaries (CONT; n = 136); 2) in vitro maturation using immature oocytes obtained by ovum pick-up (OPU) from unstimulated heifers (IMA; n = 433); 3) in vitro maturation using immature oocytes obtained by OPU from stimulated heifers (FSH; n = 444); and 4) in vivo maturation using oocytes obtained from heifers stimulated 24 hours prior by an injection of GnRH (MII; n = 658). A sample of matured oocytes from each fresh group was analyzed by matrix associated laser desorption-ionization (MALDI-TOF) to determine their PM composition. Then, half of the matured oocytes from each group were vitrified/warmed (CONT VIT, IMA VIT, FSH VIT and MII VIT), while the other half were used as fresh controls. Afterwards, the eight groups underwent IVF and IVC, and blastocyst development was assessed at D2, D7 and D8. A chi-square test was used to compare embryo development between the groups. Corresponding phospholipid ion intensity was expressed in arbitrary units, and following principal components analyses (PCA) the data were distributed on a 3D graph. Oocytes obtained from superstimulated animals showed a greater rate of developmental (P<0.05) at D7 (MII = 62.4±17.5% and FSH = 58.8±16.1%) compared to those obtained from unstimulated animals (CONT = 37.9±8.5% and IMA = 50.6±14.4%). However, the maturation system did not affect the resistance of oocytes to vitrification because the blastocyst rate at D7 was similar (P>0.05) for all groups (CONT VIT = 2.8±3.5%, IMA VIT = 2.9±4.0%, FSH VIT = 4.3±7.2% and MII VIT = 3.6±7.2%). MALDI-TOF revealed that oocytes from all maturation groups had similar phospholipid contents, except for 760.6 ([PC (34:1) + H]+), which was more highly expressed in MII compared to FSH (P<0.05). The results suggest that although maturation systems improve embryonic development, they do not change the PM composition nor the resistance of bovine oocytes to vitrification.

Effects of Different Maturation Systems on Bovine Oocyte Quality, Plasma Membrane Phospholipid Composition and Resistance to Vitrification and Warming

PubMed Central

Sprícigo, José F. W.; Diógenes, Mateus N.; Leme, Ligiane O.; Guimarães, Ana L.; Muterlle, Carolle V.; Silva, Bianca Damiani Marques; Solà-Oriol, David; Pivato, Ivo; Silva, Luciano Paulino; Dode, Margot A. N.

2015-01-01

The objective of this study was to evaluate the effects of different maturation systems on oocyte resistance after vitrification and on the phospholipid profile of the oocyte plasma membrane (PM). Four different maturation systems were tested: 1) in vitro maturation using immature oocytes aspirated from slaughterhouse ovaries (CONT; n = 136); 2) in vitro maturation using immature oocytes obtained by ovum pick-up (OPU) from unstimulated heifers (IMA; n = 433); 3) in vitro maturation using immature oocytes obtained by OPU from stimulated heifers (FSH; n = 444); and 4) in vivo maturation using oocytes obtained from heifers stimulated 24 hours prior by an injection of GnRH (MII; n = 658). A sample of matured oocytes from each fresh group was analyzed by matrix associated laser desorption-ionization (MALDI-TOF) to determine their PM composition. Then, half of the matured oocytes from each group were vitrified/warmed (CONT VIT, IMA VIT, FSH VIT and MII VIT), while the other half were used as fresh controls. Afterwards, the eight groups underwent IVF and IVC, and blastocyst development was assessed at D2, D7 and D8. A chi-square test was used to compare embryo development between the groups. Corresponding phospholipid ion intensity was expressed in arbitrary units, and following principal components analyses (PCA) the data were distributed on a 3D graph. Oocytes obtained from superstimulated animals showed a greater rate of developmental (P<0.05) at D7 (MII = 62.4±17.5% and FSH = 58.8±16.1%) compared to those obtained from unstimulated animals (CONT = 37.9±8.5% and IMA = 50.6±14.4%). However, the maturation system did not affect the resistance of oocytes to vitrification because the blastocyst rate at D7 was similar (P>0.05) for all groups (CONT VIT = 2.8±3.5%, IMA VIT = 2.9±4.0%, FSH VIT = 4.3±7.2% and MII VIT = 3.6±7.2%). MALDI-TOF revealed that oocytes from all maturation groups had similar phospholipid contents, except for 760.6 ([PC (34:1) + H]+), which was more highly expressed in MII compared to FSH (P<0.05). The results suggest that although maturation systems improve embryonic development, they do not change the PM composition nor the resistance of bovine oocytes to vitrification. PMID:26107169

Behaviour of the vitelline envelope in Bufo arenarum oocytes matured in vitro in blockade to polyspermy.

PubMed

Oterino, J; Sánchez Toranzo, G; Zelarayán, L; Ajmat, M T; Bonilla, F; Bühler, M I

2006-05-01

During activation of amphibian eggs, cortical granule exocytosis causes elaborate ultrastructural changes in the vitelline envelope. These changes involve modifications in the structure of the vitelline envelope and formation of a fertilization envelope (FE) that can no longer be penetrated by sperm. In Bufo arenarum, as the egg traverses the oviduct, the vitelline envelope is altered by a trypsin-like protease secreted by the oviduct, which induces an increased susceptibility of the vitelline envelope to sperm lysins. Full-grown oocytes of B. arenarum, matured in vitro by progesterone, are polyspermic, although cortical granule exocytosis seems to occur within a normal chronological sequence. These oocytes can be fertilized with or without trypsin treatment, suggesting that the vitelline envelope is totally sperm-permeable. Vitelline envelopes without trypsin treatment cannot retain either gp90 or gp96. This suggests that these glycoproteins are involved in the block to polyspermy and that trypsin treatment of matured in vitro oocytes before insemination is necessary to enable vitelline envelopes to block polyspermy. The loss of the binding capacity in vitelline envelopes isolated from B. arenarum oocytes matured in vitro with trypsin treatment and activated by electric shock suggests that previous trypsin treatment is a necessary step for sperm block to occur. When in vitro matured oocytes were incubated with the product of cortical granules obtained from in vitro matured oocytes (vCGP), vitelline envelopes with trypsin treatment were able to block sperm entry. These oocytes exhibited the characteristic signs of activation. These results support the idea that B. arenarum oocytes can be activated by external stimuli and suggest the presence of unknown oocyte surface receptors linked to the activation machinery in response to fertilization. Electrophoretic profiles obtained by SDS-PAGE of solubilized vitelline envelopes from oocytes matured in vitro revealed the conversion of gp40 (in vitro matured oocytes, without trypsin treatment) to gp38 (ascribable to trypsin activity or cortical granule product activity, CGP) and the conversion of gp70 to gp68 (ascribable to trypsin activity plus CGP activity). Taking into account that only the vitelline envelopes of in vitro matured oocytes with trypsin treatment and activated can block sperm entry, we may suggest that the conversion of gp70 to gp68 is related to the changes associated with sperm binding.

Melatonin improves the fertilization ability of post-ovulatory aged mouse oocytes by stabilizing ovastacin and Juno to promote sperm binding and fusion.

PubMed

Dai, Xiaoxin; Lu, Yajuan; Zhang, Mianqun; Miao, Yilong; Zhou, Changyin; Cui, Zhaokang; Xiong, Bo

2017-03-01

What are the underlying mechanisms of the decline in the fertilization ability of post-ovulatory aged oocytes? Melatonin improves the fertilization ability of post-ovulatory aged oocytes by reducing aging-induced reactive oxygen species (ROS) levels and inhibiting apoptosis and by maintaining the levels and localization of the fertilization proteins, ovastacin and Juno. Following ovulation, the quality of mammalian metaphase II oocytes irreversibly deteriorates over time with a concomitant loss of fertilization ability. Melatonin has been found to prevent post-ovulatory oocyte aging and extend the window for optimal fertilization in mice. Mouse oocytes were randomly assigned to three groups and aged in vitro for 0, 6, 12 and 24 h, respectively. Increasing concentrations of melatonin (10-9 M, 10-7 M, 10-5 M and 10-3 M) were added to the 24 h aging group. Sperm binding assays, in-vitro fertilization, immunofluorescent staining and western blotting were performed to investigate key regulators and events during fertilization of post-ovulatory aged mouse oocytes. We found that the actin cap which promotes a cortical granule (CG) free domain is disrupted with a re-distribution of CGs in the subcortex of aged oocytes. Ovastacin, a CG metalloendoprotease, is mis-located and prematurely exocytosed in aged oocytes with subsequent cleavage of the zona pellucida protein ZP2. This disrupts the sperm recognition domain and dramatically reduces the number of sperm binding to the zona pellucida. The abundance of Juno, the sperm receptor on the oocyte membrane, also is reduced in aged oocytes. Exposure of aged oocytes to melatonin significantly elevates in-vitro fertilization rates potentially by rescuing the above age-associated defects of fertilization, and reducing ROS and inhibiting apoptosis. N/A. We explored the mechanisms of the decline in fertilization ability decline in aged mouse oocytes, in vitro but not in vivo. Our findings may contribute to the development a more efficient method, involving melatonin, for improving IVF success rates. This study was supported by the National Natural Science Foundation (31571545) and the Natural Science Foundation of Jiangsu Province (BK20150677). The authors have no conflict of interest to disclose. © The Author 2017. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Ultrastructural analysis of oocytes of Rhipicephalus (Boophilus) annulatus during postengorgement period as a tool to evaluate the cytotoxic effects of amitraz and deltamethrin on the germinative cells.

PubMed

Sreelekha, Kanapadinchareveetil; Chandrasekhar, Leena; Kartha, Harikumar S; Ravindran, Reghu; Juliet, Sanis; Ajithkumar, Karapparambu G; Nair, Suresh N; Ghosh, Srikanta

2017-11-30

The present study utilizes the ultrastructural analysis of the fully engorged female Rhipicephalus (Boophilus) annulatus ticks, as a tool to evaluate the cytotoxic potential of deltamethrin and amitraz on the germinative cells. The ultrastructural analysis of the ovary of the normal (untreated) R (B.) annulatus revealed, oocytes in different stages of development, attached to the ovary wall by pedicel cells. The attachment site of oocyte to the pedicel cell was characterized by indentations of the plasma membrane. The oocyte was bound by three cell membranes viz., plasma membrane, chorion and basal lamina. The stages of oocytes were differentiated ultrastructurally based on the features of their outer membrane and the number and size of lipid and yolk droplets. Detailed day wise analysis of ultrastructural changes in the ovary during the post-engorgement period revealed the occurrence of the degenerative changes from day five onwards. These appeared first in the oocytes followed by the germinal epithelium. The ovary of ticks treated with methanol (control), revealed similar topographies as that of a normal ovary except for the presence of very few oocytes with ring shaped nucleoli. Ultrastructurally, treatment with deltamethrin produced more prominent and extensive morphological alterations when compared to amitraz. In the case of ticks treated with amitraz, the oocytes of stage IV and V showed wavy and disrupted outer boundaries along with the loss of integrity of the yolk droplets. Uneven nuclear membranes of stage II oocytes and cristolysis of mitochondria of mature oocytes were the other changes noticed. Ticks treated with deltamethrin revealed prominent modifications such as, detachment of the basal lamina, wrinkled boundary, inconsistent nuclear membrane, ring shaped nucleoli and chromatin clumping in the case of the early stage oocytes (I and II), whereas swelling and cristolysis of mitochondria were seen in mature oocytes. The study further indicated that, in addition to the previous proven neurotoxic effects, these compounds act directly on the ovary of tick. Copyright © 2017 Elsevier B.V. All rights reserved.

Identification of candidate miRNAs and expression profile of yak oocytes before and after in vitro maturation by high-throughput sequencing.

PubMed

Xiong, X R; Lan, D L; Li, J; Zi, X D; Li, M Y

2016-12-01

Small RNA represents several unique non-coding RNA classes that have important function in a wide range of biological processes including development of germ cells and early embryonic, cell differentiation, cell proliferation and apoptosis in diverse organisms. However, little is known about their expression profiles and effects in yak oocytes maturation and early development. To investigate the function of small RNAs in the maturation process of yak oocyte and early development, two small RNA libraries of oocytes were constructed from germinal vesicle stage (GV) and maturation in vitro to metaphase II-arrested stage (M II) and then sequenced using small RNA high-throughput sequencing technology. A total of 9,742,592 and 12,168,523 clean reads were obtained from GV and M II oocytes, respectively. In total, 801 and 1,018 known miRNAs were acquired from GV and M II oocytes, and 75 miRNAs were found to be significantly differentially expressed: 47 miRNAs were upregulated and 28 miRNAs were downregulated in the M II oocytes compared to the GV stage. Among the upregulated miRNAs, miR-342 has the largest fold change (9.25-fold). Six highly expressed miRNAs (let-7i, miR-10b, miR-10c, miR-143, miR-146b and miR-148) were validated by real-time quantitative PCR (RT-qPCR) and consistent with the sequencing results. Furthermore, the expression patterns of two miRNAs and their potential targets were analysed in different developmental stages of oocytes and early embryos. This study provides the first miRNA profile in the mature process of yak oocyte. Seventy-five miRNAs are expressed differentially in GV and M II oocytes as well as among different development stages of early embryos, suggesting miRNAs involved in regulating oocyte maturation and early development of yak. These results showed specific miRNAs in yak oocytes had dynamic changes during meiosis. Further functional and mechanistic studies on the miRNAs during meiosis may beneficial to understanding the role of miRNAs on meiotic division. © 2016 Blackwell Verlag GmbH.

[Analysis of the Localization of Fibrillarin and Sites of Pre-rRNA Synthesis in the Nucleolus-Like Bodies of Mouse GV Oocytes after Mild Treatment with Proteinase K].

PubMed

Shishova, K V; Khodarovich, Yu M; Lavrentyeva, E A; Zatsepina, O V

2015-01-01

Postnatal development of mammalian oocytes is accompanied by functional and structural remodeling of the nucleolar apparatus: the final stage of this process is the formation of large objects (up to 10 μm in diameter) termed nucleolus-like bodies (NLBs) in preovulatory GV oocytes. N LB material was shown to be essential for early embryonic development, but its composition is still uncharacterized. In the present study, the protein-binding dye fluorescein-5-isothiocyanate (FITC) was used to show that proteins characterized by a high local concentration are essential NLB components in mouse GV oocytes. One of these proteins was able to be identified for the first time using a mild treatment of oocytes with proteinase K; the protein identified was fibrillarin, a factor of early pre-rRNA processing. Fibrillarin is present in the inner NLB mass of all oocytes capable of synthesizing rRNA; however, it is not colocalized with BrUTP microinjected into oocytes in order to identify transcribed ribosomal genes, in contrast to the "surface" fibrillarin. These observations imply the accumulation of nucleolar proteins not involved in ribosome biogenesis inside the NLB. All NLBs present in an individual nucleus of an NSN-type GV oocyte contain fibrillarin and are associated with active ribosomal genes. The results obtained in the present work demonstrate that proteinase K treatment of GV mouse oocytes allows for: (1) identification of "cryptic" proteins inside the densely packed NLB material and (2) the enhancement of oocyte image quality during BrUTP-based identification of rRNA synthesis sites but (3) not for the detection of active ribosomal genes in the inner mass of the NLB. The fluorescent dye FITC can be recommended for assessment of intracellular protein localization in the oocytes of all mammalian species.

Progressive obesity alters the steroidogenic response to ovulatory stimulation and increases the abundance of mRNAs stored in the ovulated oocyte.

PubMed

Pohlmeier, William E; Xie, Fang; Kurz, Scott G; Lu, Ningxia; Wood, Jennifer R

2014-08-01

Obese women who are able to attain pregnancy are at increased risk for early-pregnancy loss due, in part, to reduced oocyte quality. We and others have demonstrated that female Lethal Yellow (LY) mice and female C57BL/6 mice fed a high fat diet (B6-HFD) exhibit phenotypes consistent with human obesity. These studies also showed that zygotes collected from LY and B6-HFD females have reduced developmental competence. The current hypothesis is that LY and B6-HFD females exhibit an abnormal response to gonadotropin stimulation compared to C57BL/6 controls fed normal rodent chow (B6-ND), resulting in the ovulation of oocytes with an altered molecular phenotype which may contribute to its reduced developmental competence. To test this hypothesis, age-matched B6-ND, B6-HFD, and LY females were stimulated with exogenous gonadotropins, then circulating hormone levels and the phenotypes of ovulated oocytes were analyzed. There was no difference in ovulation rate or in the percentage of morphologically abnormal oocytes collected from the oviduct of any females. Progesterone and progesterone/estradiol ratios, however, were increased in B6-HFD and LY compared to B6-ND females 16 hr post-human chorionic gonadotropin treatment. The transcript abundance of several candidate oocyte genes was also increased in B6-HFD- and LY-derived oocytes compared to B6-ND-derived oocytes. These data suggest that increased insulin and leptin levels of obese females elevated circulating progesterone concentrations, altered transcriptional activity during oocyte growth, and/or impaired mechanisms of RNA translation and degradation during oocyte maturation. These changes in mRNA abundance likely contribute to reduced oocyte quality and the subsequent poor embryogenesis associated with obesity. © 2014 Wiley Periodicals, Inc.

Arachidonic and linoleic acid derivatives impact oocyte ICSI fertilization--a prospective analysis of follicular fluid and a matched oocyte in a 'one follicle--one retrieved oocyte--one resulting embryo' investigational setting.

PubMed

Ciepiela, Przemysław; Bączkowski, Tomasz; Drozd, Arleta; Kazienko, Anna; Stachowska, Ewa; Kurzawa, Rafał

2015-01-01

To evaluate human oocyte ability to undergo fertilization and subsequent preimplantation embryonic development in relation to a wide panel of follicular fluid (FF) arachidonic acid derivatives (AAD) and linoleic acid derivatives (LAD) of prospectively selected patients undergoing intracytoplasmic sperm injection (ICSI). Study was designed as a two center (a university clinic and a private clinic) prospective study. 54 women of 181 consecutive couples undergoing ICSI were prospectively found to be eligible for analysis. 'One follicle - one retrieved oocyte - one resulting embryo' approach was used. Each individual follicle was aspirated independently and matched to an oocyte growing in this particular follicular milieu. FF samples were assessed for AAD and LAD by high-performance liquid chromatography; additionally, activity of secretory phospholipase A (sPLA2) was determined by enzyme-linked immunosorbent assay. Increased activity of sPLA2 and significantly higher AAD and LAD levels were found in FF of oocytes that did not show two pronuclei or underwent degeneration after ICSI in comparison to oocytes with the appearance of two pronuclei. Receiver operating characteristics curve analysis identified acids with the highest sensitivity and specificity: 5oxo-hydroxyeicosatetraenoic, 16-hydroxyeicosatetraenoic, 9-hydroxyoctadecadieneoic and 12-hydroxyeicosatetraenoic. No significant differences between AAD and LAD related to embryo quality were found. Our study demonstrates for the first time that elevated concentrations of AAD and LAD in FF at the time of oocyte retrieval significantly decrease the ability of oocytes to form pronuclei after ICSI. This may serve as a new tool for non-invasive assessment of oocyte developmental capacity. However, levels of AAD and LAD are not associated with subsequent embryo quality or pregnancy rate, and therefore more studies are needed to determine their usefulness in human IVF procedure.

Fat area and lipid droplet morphology of porcine oocytes during in vitro maturation with trans-10, cis-12 conjugated linoleic acid and forskolin.

PubMed

Prates, E G; Marques, C C; Baptista, M C; Vasques, M I; Carolino, N; Horta, A E M; Charneca, R; Nunes, J T; Pereira, R M

2013-04-01

Lipid droplets (LD) in porcine oocytes form a dark mass reaching almost all cytoplasm. Herein we investigated changes in fat areas, cytoplasmic tone and LD morphology during in vitro maturation (IVM) of porcine oocytes cultured with 100 μM trans-10, cis-12 conjugated linoleic acid (t10,c12 CLA) or 10 μM forskolin at different time periods. Four groups were constituted: control, excipient, t10,c12 CLA and forskolin, with drugs being supplemented during 44 to 48 h and the initial 22 to 24 h in Experiments 1 and 2, respectively. In Experiment 3, forskolin was supplemented for the first 2 h. Matured oocytes were inseminated with frozen-thawed boar semen and cleavage rate recorded. Before and during IVM, samples of oocytes were evaluated for LD, total and fat areas and fat gray value or for meiotic progression. Results showed that forskolin supplementation during 44 to 48 h or 22 to 24 h inhibits oocyte maturation (exp. 1: forskolin = 5.1 ± 8.0%, control = 72.6 ± 5.0%; exp. 2: forskolin = 24.3 ± 7.4%, control = 71.6 ± 5.6%) and cleavage (exp. 1: forskolin = 0.0 ± 0.0%, control = 55.4 ± 4.1%; exp. 2: forskolin = 8.3 ± 3.3%, control = 54.5 ± 3.0%). Forskolin also reduced oocyte and fat areas. In Experiment 3, forskolin negative effect on oocyte maturation and cleavage disappeared, although minor (P ⩽ 0.03) LD and oocyte fat areas were identified at 22 to 24 h of IVM. Oocytes supplemented with t10,c12 CLA during 44 to 48 h presented a lighter (P ⩽ 0.04) colour tone cytoplasm than those of control and forskolin. In conclusion, t10,c12 CLA and forskolin were capable of modifying the distribution and morphology of cytoplasmic LD during porcine oocyte maturation, thus reducing its lipid content in a time-dependent manner.

Lithobates catesbeianus (American Bullfrog) oocytes: a novel heterologous expression system for aquaporins

PubMed Central

2018-01-01

ABSTRACT Xenopus laevis oocytes are a valuable tool for investigating the function of membrane proteins. However, regulations around the world, specifically in Brazil, render the import of Xenopus laevis frogs impractical, and, in some cases, impossible. Here, as an alternative, we evaluate the usefulness of the North American aquatic bullfrog Lithobates catesebeianus, which is commercially available in Brazil, for the heterologous expression of aquaporin (AQP) proteins. We have developed a method that combines a brief collagenase treatment and mechanical defolliculation for isolating individual oocytes from Lithobates ovaries. We find that they have a similar size, shape, and appearance to Xenopus oocytes and can tolerate and survive following injections with cRNA or water. Furthermore, surface biotinylation, western blot analysis, and measurements of osmotic water permeability (Pf) show that Lithobates oocytes can express AQPs to the plasma membrane and significantly increase the Pf of the oocytes. In fact, the Pf values are similar to historical values gathered from Xenopus oocytes. Due to the presence of a mercury sensitive cysteine (Cys or C) in the throat of the water channel, the Pf of oocytes expressing human (h) AQP1, hAQP1FLAG [FLAG, short protein tag (DYKDDDDK) added to the N-terminus of AQP1], hAQP8, and rat (r) AQP9 was inhibited with the mercurial compound p-chloromercuribenzene sulfonate (pCMBS), whereas AQPs lacking this Cys – hAQP1C189S mutant [residue Cys 189 was replaced by a serine (Ser or S)] and hAQP7 – were mercury insensitive. Contrary to previous studies with Xenopus oocytes, rAQP3 was also found to be insensitive to mercury, which is consistent with the mercury-sensitive Cys (Cys 11) being located intracellularly. Thus, we consider Lithobates oocytes to be a readily accessible system for the functional expression and study of membrane proteins for international researchers who do not currently have access to Xenopus oocytes. PMID:29530931

Bovine oocyte meiotic inhibition before in vitro maturation and its value to in vitro embryo production: does it improve developmental competence?

PubMed

Bilodeau-Goeseels, S

2012-08-01

The efficiency of bovine in vitro embryo production has remained low despite extensive effort to understand the effects of culture conditions, media composition and supplementation. As bovine oocytes resume meiosis spontaneously when cultured, it was hypothesized that preventing meiosis in vitro before in vitro maturation (IVM) and in vitro fertilization (IVF) would allow more oocytes to acquire developmental competence. This article reviews some of the factors involved in meiotic arrest as well as the effects of meiotic inhibition before IVM on bovine oocytes developmental competence following IVF. Follicular components and cAMP-elevating agents can delay or inhibit meiosis in various proportions of oocytes; however, few studies have examined their effects on development following IVM and IVF because they are not practical (follicular components) or have a transient effect on meiosis (cAMP-elevating agents). Protein synthesis or phosphorylation inhibition prevented meiosis in high percentages of oocytes; however, these non-specific inhibitions led to lower developmental competence compared with non-arrested oocytes. Maturation promoting factor (MPF) inhibition with specific inhibitors has been examined in several studies. Despite faster maturation following removal from inhibition and some structural damage to the oocytes, MPF inhibition generally led to blastocyst rates similar to control, non-arrested oocytes. Future work will involve evaluating the effects on arrested oocytes of molecules that can improve developmental competence in non-arrested oocytes. It is also anticipated that new IVM systems that take into consideration new knowledge of the mechanisms involved in the control of meiosis will be developed. Moreover, global gene expression analysis studies will also provide clues to the culture conditions required for optimal expression of developmental competence. © Her Majesty the Queen in Right of Canada 2011. Reproduced with the permission of the Minister of Agriculture and Agri-Food Canada.

Arachidonic and Linoleic Acid Derivatives Impact Oocyte ICSI Fertilization – A Prospective Analysis of Follicular Fluid and a Matched Oocyte in a ‘One Follicle – One Retrieved Oocyte – One Resulting Embryo’ Investigational Setting

PubMed Central

Bączkowski, Tomasz; Drozd, Arleta; Kazienko, Anna

2015-01-01

Objective To evaluate human oocyte ability to undergo fertilization and subsequent preimplantation embryonic development in relation to a wide panel of follicular fluid (FF) arachidonic acid derivatives (AAD) and linoleic acid derivatives (LAD) of prospectively selected patients undergoing intracytoplasmic sperm injection (ICSI). Methodology Study was designed as a two center (a university clinic and a private clinic) prospective study. 54 women of 181 consecutive couples undergoing ICSI were prospectively found to be eligible for analysis. 'One follicle – one retrieved oocyte – one resulting embryo' approach was used. Each individual follicle was aspirated independently and matched to an oocyte growing in this particular follicular milieu. FF samples were assessed for AAD and LAD by high-performance liquid chromatography; additionally, activity of secretory phospholipase A (sPLA2) was determined by enzyme-linked immunosorbent assay. Principal Findings Increased activity of sPLA2 and significantly higher AAD and LAD levels were found in FF of oocytes that did not show two pronuclei or underwent degeneration after ICSI in comparison to oocytes with the appearance of two pronuclei. Receiver operating characteristics curve analysis identified acids with the highest sensitivity and specificity: 5oxo-hydroxyeicosatetraenoic, 16-hydroxyeicosatetraenoic, 9-hydroxyoctadecadieneoic and 12-hydroxyeicosatetraenoic. No significant differences between AAD and LAD related to embryo quality were found. Conclusions/Significance Our study demonstrates for the first time that elevated concentrations of AAD and LAD in FF at the time of oocyte retrieval significantly decrease the ability of oocytes to form pronuclei after ICSI. This may serve as a new tool for non-invasive assessment of oocyte developmental capacity. However, levels of AAD and LAD are not associated with subsequent embryo quality or pregnancy rate, and therefore more studies are needed to determine their usefulness in human IVF procedure. PMID:25763593

Effect of Antioxidants (β-mercaptoethanol and Cysteamine) on Assisted Reproductive Technology In vitro.

PubMed

Nikseresht, Mohsen; Toori, Mehdi Akbartabar; Rahimi, Hamid Reza; Fallahzadeh, Ali Reza; Kahshani, Iraj Ragerdi; Hashemi, Seyedeh Fatemeh; Bahrami, Solmaz; Mahmoudi, Reza

2017-02-01

Oocyte Culture of Germinal Vesicle (GV) and its growth improves Assisted Reproductive Technology (ART) invitro and infertility. Inappropriate culture medium environment, low quality of oocytes, increase in Oxidative Stress (OS) events, Reactive Oxygen Species (ROS) and free radicals production are the main factors that result in unsuccessful Invitro Maturation (IVM) and decrease in reproduction. The present study was conducted with the aim to evaluate the effect of β-mercaptoethanol (BME) and Cysteamine (CYS) on IVM improvement, embryo fertilization and development of blastocyst of mouse immature oocyte. Oocytes were obtained from 4-6 weeks old Naval Medical Research Institute (NMRI) female mice, 48 hours after stimulation with Intraperitoneal (IP) injection of 10 IU Pregnant Mare Serum Gonadotropin (PMSG). GV oocyte with and without cumulus cells were isolated from ovaries and cultured in Tissue Culture Medium (TCM) 199 with availability of 100 μM of antioxidants (BME and CYS). After 24 hours, mature oocyte in metaphase II (MII) were fertilized with sperm in In vitro Fertilization (IVF) medium (T6) and evaluated for fetal development into blastocyst. BME and CYS could significantly (p<0.05) increase the rate of IVM and oocyte evolution, and embryo formation in medium culture. Furthermore, it is demonstrated that existence of Cumulus Oocyte Complexes (COC) significantly showed better IVM, fertilization and evolution trend as compared to oocytes without cumulus cover or Denuded Oocytes (DO), especially in TCM199 plus BME and CYS. So that the change in GV stage oocytes to MII (maturation rate), fertilization rates or 2PN formation, and two cell embryos formation or blastocyst development rate in the treatment group with addition of BME & CYS and COC was statistically significant as compared to the DO group (p-value < 0.0001). Both cellular and environmental factors could be important and involved in ART improvement.

Follicle Size on Day of Trigger Most Likely to Yield a Mature Oocyte.

PubMed

Abbara, Ali; Vuong, Lan N; Ho, Vu N A; Clarke, Sophie A; Jeffers, Lisa; Comninos, Alexander N; Salim, Rehan; Ho, Tuong M; Kelsey, Tom W; Trew, Geoffrey H; Humaidan, Peter; Dhillo, Waljit S

2018-01-01

To identify follicle sizes on the day of trigger most likely to yield a mature oocyte following hCG, GnRH agonist (GnRHa), or kisspeptin during IVF treatment. Retrospective analysis to determine the size of follicles on day of trigger contributing most to the number of mature oocytes retrieved using generalized linear regression and random forest models applied to data from IVF cycles (2014-2017) in which either hCG, GnRHa, or kisspeptin trigger was used. HCG and GnRHa data were collected at My Duc Hospital, Ho Chi Minh City, Vietnam, and kisspeptin data were collected at Hammersmith Hospital, London, UK. Four hundred and forty nine women aged 18-38 years with antral follicle counts 4-87 were triggered with hCG ( n  = 161), GnRHa ( n  = 165), or kisspeptin ( n  = 173). Follicle sizes on the day of trigger most likely to yield a mature oocyte. Follicles 12-19 mm on the day of trigger contributed the most to the number of oocytes and mature oocytes retrieved. Comparing the tertile of patients with the highest proportion of follicles on the day of trigger 12-19 mm, with the tertile of patients with the lowest proportion within this size range, revealed increases of 4.7 mature oocytes for hCG ( P  < 0.0001) and 4.9 mature oocytes for GnRHa triggering ( P  < 0.01). Using simulated follicle size profiles of patients with 20 follicles on the day of trigger, our model predicts that the number of oocytes retrieved would increase from a mean 9.8 (95% prediction limit 9.3-10.3) to 14.8 (95% prediction limit 13.3-16.3) oocytes due to the difference in follicle size profile alone. Follicles 12-19 mm on the morning of trigger administration were most likely to yield a mature oocyte following hCG, GnRHa, or kisspeptin.

Cryopreserved oocyte versus fresh oocyte assisted reproductive technology cycles, United States, 2013

PubMed Central

Crawford, Sara; Boulet, Sheree L.; Kawwass, Jennifer F.; Jamieson, Denise J.; Kissin, Dmitry M.

2017-01-01

Objective To compare characteristics, explore predictors, and compare assisted reproductive technology (ART) cycle, transfer, and pregnancy outcomes of autologous and donor cryopreserved oocyte cycles with fresh oocyte cycles. Design Retrospective cohort study from the National ART Surveillance System. Setting Fertility treatment centers. Patient(s) Fresh embryo cycles initiated in 2013 utilizing embryos created with fresh and cryopreserved, autologous and donor oocytes. Intervention(s) Cryopreservation of oocytes versus fresh. Main Outcomes Measure(s) Cancellation, implantation, pregnancy, miscarriage, and live birth rates per cycle, transfer, and/or pregnancy. Result(s) There was no evidence of differences in cancellation, implantation, pregnancy, miscarriage, or live birth rates between autologous fresh and cryopreserved oocyte cycles. Donor cryopreserved oocyte cycles had a decreased risk of cancellation before transfer (adjusted risk ratio [aRR] 0.74, 95% confidence interval [CI] 0.57–0.96) as well as decreased likelihood of pregnancy (aRR 0.88, 95% CI 0.81–0.95) and live birth (aRR 0.87, 95% CI 0.80–0.95); however, there was no evidence of differences in implantation, pregnancy, or live birth rates when cycles were restricted to those proceeding to transfer. Donor cryopreserved oocyte cycles proceeding to pregnancy had a decreased risk of miscarriage (aRR 0.75, 95% CI 0.58–0.97) and higher live birth rate (aRR 1.05, 95% CI 1.01–1.09) with the transfer of one embryo, but higher miscarriage rate (aRR 1.28, 95% CI 1.07–1.54) and lower live birth rate (aRR 0.95, 95% CI 0.92–0.99) with the transfer of two or more. Conclusion(s) There was no evidence of differences in ART outcomes between autologous fresh and cryopreserved oocyte cycles. There was evidence of differences in per-cycle and per-pregnancy outcomes between donor cryopreserved and fresh oocyte cycles, but not in per-transfer outcomes. PMID:27842997

Cryopreserved oocyte versus fresh oocyte assisted reproductive technology cycles, United States, 2013.

PubMed

Crawford, Sara; Boulet, Sheree L; Kawwass, Jennifer F; Jamieson, Denise J; Kissin, Dmitry M

2017-01-01

To compare characteristics, explore predictors, and compare assisted reproductive technology (ART) cycle, transfer, and pregnancy outcomes of autologous and donor cryopreserved oocyte cycles with fresh oocyte cycles. Retrospective cohort study from the National ART Surveillance System. Fertility treatment centers. Fresh embryo cycles initiated in 2013 utilizing embryos created with fresh and cryopreserved, autologous and donor oocytes. Cryopreservation of oocytes versus fresh. Cancellation, implantation, pregnancy, miscarriage, and live birth rates per cycle, transfer, and/or pregnancy. There was no evidence of differences in cancellation, implantation, pregnancy, miscarriage, or live birth rates between autologous fresh and cryopreserved oocyte cycles. Donor cryopreserved oocyte cycles had a decreased risk of cancellation before transfer (adjusted risk ratio [aRR] 0.74, 95% confidence interval [CI] 0.57-0.96) as well as decreased likelihood of pregnancy (aRR 0.88, 95% CI 0.81-0.95) and live birth (aRR 0.87, 95% CI 0.80-0.95); however, there was no evidence of differences in implantation, pregnancy, or live birth rates when cycles were restricted to those proceeding to transfer. Donor cryopreserved oocyte cycles proceeding to pregnancy had a decreased risk of miscarriage (aRR 0.75, 95% CI 0.58-0.97) and higher live birth rate (aRR 1.05, 95% CI 1.01-1.09) with the transfer of one embryo, but higher miscarriage rate (aRR 1.28, 95% CI 1.07-1.54) and lower live birth rate (aRR 0.95, 95% CI 0.92-0.99) with the transfer of two or more. There was no evidence of differences in ART outcomes between autologous fresh and cryopreserved oocyte cycles. There was evidence of differences in per-cycle and per-pregnancy outcomes between donor cryopreserved and fresh oocyte cycles, but not in per-transfer outcomes. Published by Elsevier Inc.

In vitro acute exposure to DEHP affects oocyte meiotic maturation, energy and oxidative stress parameters in a large animal model.

PubMed

Ambruosi, Barbara; Uranio, Manuel Filioli; Sardanelli, Anna Maria; Pocar, Paola; Martino, Nicola Antonio; Paternoster, Maria Stefania; Amati, Francesca; Dell'Aquila, Maria Elena

2011-01-01

Phthalates are ubiquitous environmental contaminants because of their use in plastics and other common consumer products. Di-(2-ethylhexyl) phthalate (DEHP) is the most abundant phthalate and it impairs fertility by acting as an endocrine disruptor. The aim of the present study was to analyze the effects of in vitro acute exposure to DEHP on oocyte maturation, energy and oxidative status in the horse, a large animal model. Cumulus cell (CC) apoptosis and oxidative status were also investigated. Cumulus-oocyte complexes from the ovaries of slaughtered mares were cultured in vitro in presence of 0.12, 12 and 1200 µM DEHP. After in vitro maturation (IVM), CCs were removed and evaluated for apoptosis (cytological assessment and TUNEL) and intracellular reactive oxygen species (ROS) levels. Oocytes were evaluated for nuclear chromatin configuration. Matured (Metaphase II stage; MII) oocytes were further evaluated for cytoplasmic energy and oxidative parameters. DEHP significantly inhibited oocyte maturation when added at low doses (0.12 µM; P<0.05). This effect was related to increased CC apoptosis (P<0.001) and reduced ROS levels (P<0.0001). At higher doses (12 and 1200 µM), DEHP induced apoptosis (P<0.0001) and ROS increase (P<0.0001) in CCs without affecting oocyte maturation. In DEHP-exposed MII oocytes, mitochondrial distribution patterns, apparent energy status (MitoTracker fluorescence intensity), intracellular ROS localization and levels, mt/ROS colocalization and total SOD activity did not vary, whereas increased ATP content (P<0.05), possibly of glycolytic origin, was found. Co-treatment with N-Acetyl-Cysteine reversed apoptosis and efficiently scavenged excessive ROS in DEHP-treated CCs without enhancing oocyte maturation. In conclusion, acute in vitro exposure to DEHP inhibits equine oocyte maturation without altering ooplasmic energy and oxidative stress parameters in matured oocytes which retain the potential to be fertilized and develop into embryos even though further studies are necessary to confirm this possibility.

In Vitro Acute Exposure to DEHP Affects Oocyte Meiotic Maturation, Energy and Oxidative Stress Parameters in a Large Animal Model

PubMed Central

Sardanelli, Anna Maria; Pocar, Paola; Martino, Nicola Antonio; Paternoster, Maria Stefania; Amati, Francesca; Dell'Aquila, Maria Elena

2011-01-01

Phthalates are ubiquitous environmental contaminants because of their use in plastics and other common consumer products. Di-(2-ethylhexyl) phthalate (DEHP) is the most abundant phthalate and it impairs fertility by acting as an endocrine disruptor. The aim of the present study was to analyze the effects of in vitro acute exposure to DEHP on oocyte maturation, energy and oxidative status in the horse, a large animal model. Cumulus cell (CC) apoptosis and oxidative status were also investigated. Cumulus-oocyte complexes from the ovaries of slaughtered mares were cultured in vitro in presence of 0.12, 12 and 1200 µM DEHP. After in vitro maturation (IVM), CCs were removed and evaluated for apoptosis (cytological assessment and TUNEL) and intracellular reactive oxygen species (ROS) levels. Oocytes were evaluated for nuclear chromatin configuration. Matured (Metaphase II stage; MII) oocytes were further evaluated for cytoplasmic energy and oxidative parameters. DEHP significantly inhibited oocyte maturation when added at low doses (0.12 µM; P<0.05). This effect was related to increased CC apoptosis (P<0.001) and reduced ROS levels (P<0.0001). At higher doses (12 and 1200 µM), DEHP induced apoptosis (P<0.0001) and ROS increase (P<0.0001) in CCs without affecting oocyte maturation. In DEHP-exposed MII oocytes, mitochondrial distribution patterns, apparent energy status (MitoTracker fluorescence intensity), intracellular ROS localization and levels, mt/ROS colocalization and total SOD activity did not vary, whereas increased ATP content (P<0.05), possibly of glycolytic origin, was found. Co-treatment with N-Acetyl-Cysteine reversed apoptosis and efficiently scavenged excessive ROS in DEHP-treated CCs without enhancing oocyte maturation. In conclusion, acute in vitro exposure to DEHP inhibits equine oocyte maturation without altering ooplasmic energy and oxidative stress parameters in matured oocytes which retain the potential to be fertilized and develop into embryos even though further studies are necessary to confirm this possibility. PMID:22076161

Analysis of the roles of cyclin B1 and cyclin B2 in porcine oocyte maturation by inhibiting synthesis with antisense RNA injection.

PubMed

Kuroda, Takao; Naito, Kunihiko; Sugiura, Koji; Yamashita, Masakane; Takakura, Ikuko; Tojo, Hideaki

2004-01-01

The function of cyclin B1 (CB1) and cyclin B2 (CB2) during porcine oocyte maturation was investigated by injecting oocytes with their antisense RNAs (asRNAs). At first, protein levels of both cyclin Bs were examined by immunoblotting, revealing that immature oocytes had only CB2, at a level comparable to 1/20 to 1/40 of that detected in first metaphase oocytes. Both cyclin B syntheses were started around germinal vesicle breakdown (GVBD); CB1 and CB2 peaked at the second metaphase and first metaphase, respectively. We obtained a porcine CB2 cDNA fragment, which was 88% homologous with human CB2, by reverse-transcriptase polymerase chain reaction (RT-PCR) using total RNAs of immature porcine oocytes and a primer set of human CB2. Specific asRNAs of CB1 and CB2 were prepared in vitro. Then one, the other, or both were injected into the cytoplasm of immature oocytes. CB1 asRNA inhibited CB1 synthesis specifically; the injected oocytes underwent first meiosis normally but could not arrest at the second meiotic metaphase. CB2 asRNA inhibited CB2 synthesis specifically, but had almost no effect on the maturation of injected oocytes. When both CB1 and CB2 asRNAs were injected, synthesis of both cyclin Bs was inhibited, and GVBD was significantly suppressed but occurred slowly. These results suggest that CB1 is the principal molecule for regulation in mammalian oocyte maturation, whereas CB2 has only an accessory role. They also show that in porcine oocytes, cyclin B synthesis is not necessary for GVBD induction itself, but synthesis of at least one cyclin B, CB1 or CB2, is necessary for GVBD induction in a normal time course.

Some quantitative indicators of postovulatory aging and its effect on larval and juvenile development of Atlantic salmon (Salmo salar).

PubMed

Mommens, Maren; Storset, Arne; Babiak, Igor

2015-07-01

Modern out-of-season egg production in Atlantic salmon (Salmo salar) increases the risk of postovulatory aging (POA) of oocytes. Postovulatory aging is known to influence oocyte quality in salmonids, but reliable tests for POA are lacking in Atlantic salmon egg production. To address this problem, we have collected oocytes from the same 20 Atlantic salmon females sequentially in approximately 1-week intervals, from the start of ovulation until 28 days postovulation (dpo), to determine the effect of natural retention of matured oocytes in body coelomic cavity on further performance of embryos and juveniles produced from those oocytes. Also, we investigated oocyte water hardening and several coelomic fluid parameters as potential quantitative indicators of POA. Oocyte quality decreased significantly from 22 dpo onward, as inferred from decrease in fertilization success and survival of embryos, alevins, and juveniles and increase in alevin and juvenile deformity rates. The occurrence of head deformities was significantly related to postovulatory age of oocytes. Coelomic fluid pH decreased significantly at 28 dpo and correlated positively with fertilization rates (r = 0.45), normal eyed embryo rates (r = 0.67), and alevin relative survival rates (r = 0.63) and negatively correlated with total alevin deformity rates (r = -0.59). Oocyte weight gain at 60 minutes decreased significantly at 28 dpo and correlated negatively with total alevin deformities and the occurrence of cranial nodules (r = -0.99). Generally, quality of ovulated oocytes remained stable for the first 2 weeks after ovulation. Later on, POA negatively influenced Atlantic salmon embryo, alevin, and juvenile performance. For the first time, we show a long-term effect of POA on salmonid juvenile performance. Standardized pH measurements of coelomic fluid could potentially improve embryo and juvenile production by identifying low-quality oocytes at an early stage during the production. Copyright © 2015 Elsevier Inc. All rights reserved.

Immunophotoaffinity labeling of binders of 1-methyladenine, the oocyte maturation-inducing hormone of starfish

DOE Office of Scientific and Technical Information (OSTI.GOV)

Toraya, Tetsuo; Kida, Tetsuo; Kuyama, Atsushi

Starfish oocytes are arrested at the prophase stage of the first meiotic division in the ovary and resume meiosis by the stimulus of 1-methyladenine (1-MeAde), the oocyte maturation-inducing hormone of starfish. Putative 1-MeAde receptors on the oocyte surface have been suggested, but not yet been biochemically characterized. Immunophotoaffinity labeling, i.e., photoaffinity labeling combined with immunochemical detection, was attempted to detect unknown 1-MeAde binders including putative maturation-inducing hormone receptors in starfish oocytes. When the oocyte crude membrane fraction or its Triton X-100/EDTA extract was incubated with N{sup 6}-[6-(5-azido-2-nitrobenzoyl)aminohexyl]carboxamidomethyl-1-methyladenine and then photo-irradiated, followed by western blotting with antibody that was raised againstmore » a 1-MeAde hapten, a single band with M{sub r} of 47.5 K was detected. The band was lost when extract was heated at 100 °C. A similar 47.5 K band was detected in the crude membrane fraction of testis as well. Upon labeling with whole cells, this band was detected in immature and maturing oocytes, but only faintly in mature oocytes. As judged from these results, this 1-MeAde binder might be a possible candidate of the starfish maturation-inducing hormone receptors. - Highlights: • Synthesis of photoaffinity labeling reagents for 1-methyladenine binders of starfish. • Immunochemical detection of photoaffinity-labeled 1-methyladenine binders. • Immunophotoaffinity labeling of a 47.5 K 1-methyladenine binder in oocytes and testis. • A possible candidate of oocyte maturation-inducing hormone receptors of starfish.« less

The effect of the ovarian varicose vein on the DNA methylation in the rat’s oocyte

PubMed Central

Mohammadi, Amirhossein; Zangi, Bagher Minaei; Azari, Mahshid Delfan; Alizadeh, Rafieh; Salehi, Mohammad; Daneshi, Erfan; Rezaei, Mohammad Jafar; Abbasi, Mehdi

2017-01-01

Objective(s): We intended to determine whether the ovarian varicose which is one of the common etiologies of the pelvic congestion syndrome, has the ability to interfere with the DNA methylation reprogramming in the oocyte and thereby affect the oocyte quality or not. Materials and Methods: Varicose model was induced according to the Turner’s method in the rats. Briefly, a 20-gauge needle was placed on the left renal vein and a thread was tied over both the needle and the renal vein medial to the insertion of the ovarian vein, and then the needle was removed. Evaluation of prooxidant-antioxidant balance (PAB) was assessed using specific kits and the expression level of the DNA methyltransferase genes Dnmt1, Dnmt3a and Dnmt3L was assessed by Real-time PCR. Immunofluorescent staining for 5-methylcytosine in the oocytes evaluated the global DNA methylation. Results: A significant PAB increase in the ovaries from varicose group was seen. Real-time PCR demonstrated a remarkable decrease in the expression of the Dnmt3a and Dnmt3L which are responsible for de novo DNA methylation in the oocytes. Immunofluorescent staining for 5-mC showed a reduction in the fluorescence intensity in the oocytes collected from the varicose group. Conclusion: Our findings from Real-time PCR and immunocytochemistry suggest that the epigenetic parameters in the oocyte could be affected by varicose induction and these epigenetic alteration has the potential to affect the oocyte quality. We suggest that the epigenetic changes could happen in the oocytes after the induction of ovarian varicose and lead to the oocyte quality reduction or even infertility. PMID:29147493

Resveratrol Improves the Mitochondrial Function and Fertilization Outcome of Bovine Oocytes

PubMed Central

TAKEO, Shun; SATO, Daichi; KIMURA, Koji; MONJI, Yasunori; KUWAYAMA, Takehito; KAWAHARA-MIKI, Ryoka; IWATA, Hisataka

2013-01-01

The aim of the present study was to address the effect of resveratrol-mediated upregulation of sirtuin 1 (SIRT1) during oocyte maturation on mitochondrial function, the developmental ability of oocytes and on mechanisms responsible for blockage of polyspermic fertilization. Oocytes collected from slaughterhouse-derived ovaries were cultured in TCM-199 medium supplemented with 10% FCS and 0 or 20 µM resveratrol (Res). We examined the effect of Res on SIRT1 expression in in vitro-matured oocytes (Exp 1); fertilization and developmental ability (Exp 2); mitochondrial DNA copy number (Mt number), ATP content and mitochondrial membrane potential in matured oocytes (Exp 3); and the time required for proteinase to dissolve the zona pellucida following in vitro fertilization (as a marker of zona pellucida hardening), as well as on the distribution of cortical granules before and after fertilization (Exp 4). In Exp 1, the 20 µM Res treatment upregulated protein expression of SIRT1 in oocytes. In Exp 2, Res treatment improved the ratio of normal fertilization and the total cell number of blastocysts. In Exp 3, Res treatment significantly increased the ATP content in matured oocytes. Additionally, Res increased the overall Mt number and mitochondrial membrane potential, but the effect was donor-dependent. In Exp 4, Res-induced zona hardening improved the distribution and exocytosis of cortical granules after in vitro fertilization. In conclusion, Res improved the quality of oocytes by improving mitochondrial quantity and quality. In addition, Res added to the maturation medium enhanced SIRT1 protein expression in oocytes and improved fertilization via reinforcement of the mechanisms responsible for blockage of polyspermic fertilization. PMID:24390595

Ovum pick up, in vitro embryo production, and pregnancy rates from a large-scale commercial program using Nelore cattle (Bos indicus) donors.

PubMed

Pontes, J H F; Melo Sterza, F A; Basso, A C; Ferreira, C R; Sanches, B V; Rubin, K C P; Seneda, M M

2011-06-01

The objective was to clarify in vitro production of bovine embryos in Brazil. Data from 656 ovum pick-up/in vitro production (OPU/IVP) procedures, performed on 317 Nelore (Bos indicus) donors, without hormone stimulation or control of ovarian follicular waves, were analysed. Donors were subjected to OPU from one to nine times (no specific schedule), with < 15 d between consecutive procedures. There were 20,848 oocytes, of which 15,747 (75.53%) were considered viable, 5,446 embryos were obtained, 5,398 embryos were immediately transferred, resulting in 1,974 pregnancies (36.57%) at Day 30 and 1,788 (33.12%) pregnancies at Day 60. The average number of total and viable oocytes produced per OPU session was (mean ± SEM) 30.84 ± 0.88 and 23.35 ± 0.7 (average of 8.1 ± 0.3 embryos and 3.0 ± 0.1 pregnancies per OPU-IVP procedure). Since oocyte production varied widely among donor, they were designated as very high, high, intermediate, and low, with 58.94 ± 2.04, 32.61 ± 0.50, 22.13 ± 0.50, and 10.26 ± 0.57 oocytes, respectively, produced by 78, 80, 79, and 80 donors. The number of viable oocytes recovered ranged from 0 to 128; since donors with numerous viable oocytes produced many viable embryos and pregnancies, oocyte production was useful for donor selection. However, there was no significant effect of the number of OPU sessions per donor on mean numbers of oocytes produced. In conclusion, we confirmed field reports of high oocyte production by some Nelore donors and demonstrated individual variation in oocyte yield, which was associated with embryo production and pregnancy rates. Copyright © 2011 Elsevier Inc. All rights reserved.

Effect of treating induced mitochondrial damage on embryonic development and epigenesis.

PubMed

Takeuchi, Takumi; Neri, Queenie V; Katagiri, Yukiko; Rosenwaks, Zev; Palermo, Gianpiero D

2005-03-01

Germinal vesicle transplantation (GVT) has been proposed as a possible treatment to correct age-related oocyte aneuploidy caused by dysfunctional ooplasm. How healthy ooplasm regulates normal meiosis and subsequent development has yet to be elucidated, but impaired mitochondrial metabolism may be attributable to incomplete segregation of the oocyte chromosomes. In the present study, after ooplasmic mitochondrial damage by photoirradiating chloromethyl-X-rosamine, examination of the oocyte nuclei's ability to survive after transfer into healthy ooplasts was performed. To assess their fertilizability and potential for development, GVT oocytes were fertilized by intracytoplasmic sperm injection (ICSI) and transferred to foster mice. Condition of the offspring at birth was assessed, and epigenetic analysis was performed. Photosensitization consistently inhibited oocyte maturation. However, after GVT of photosensitized nuclei into healthy ooplasts, 67.2% were reconstituted, and 76.2% of these matured normally, with an overall rate of 51.2%, much higher than that (6.0%) in the mitochondrially injured oocytes. After ICSI, 65.8% (52/79) of GVT oocytes were fertilized normally, and 21.1% (11/52) eventually reached the blastocyst stage. The transfer of 132 two-cell GVT embryos into the oviducts of pseudopregnant females resulted in 17 apparently healthy live offspring. For some key developmental genes, a high level of expression was identified in the GVT and "rescue"-derived fetal adnexa. Thus, one can induce in oocyte mitochondria a photosensitization-based type of damage, which consistently inhibits GV breakdown, meiotic spindle formation, chromosomal segregation, and polar body extrusion. Germinal vesicle transplanted and rescued oocytes were able to undergo maturation, fertilization, and embryonic cleavage and, ultimately, to develop to term. This approach may provide a model with which to study the age-related ooplasmic dysfunction seen in human oocytes.

Effect of the timing of the first cleavage on the developmental potential of nuclear-transferred mouse oocytes receiving embryonic stem cells.

PubMed

Kobayashi, T; Kato, Y; Tsunoda, Y

2004-09-01

The present study examined whether the timing of the first cleavage has an effect on the in vitro and in vivo developmental potential of nuclear-transferred mouse oocytes receiving embryonic stem cells. First, the timing of the first cleavage and the developmental potential of nuclear-transferred oocytes were examined every hour from 12 to 24 h after the start of culture and compared with in vitro-fertilized oocytes. The developmental potential of in vitro-fertilized oocytes decreased gradually according to the time required for cleavage (84% (32/38) for 15 h to 50% (1/2) for 20 h), but intermediate-cleaved (15-16 h) nuclear-transferred oocytes had a higher potential to develop into blastocysts (55% (17/31) to 67% (45/67) versus 0-43% (6/14)]. Second the nuclear-transferred oocytes were divided into three groups according to the timing of the first cleavage; each group was cultured to blastocysts in vitro, and then transferred to recipients. The potential of intermediate-cleaved oocytes (15-16 h) to develop into blastocysts was significantly higher than fast-cleaved (before 15 h) and slow-cleaved (after 16 h) oocytes (65, 46, and 37%). The proportion of fetuses on Day 10.5 of pregnancy was highest in the intermediate-cleaved group (4 versus 2 and 1%, respectively) and a full-term fetus was obtained from this group. The present study demonstrated that the timing of the first cleavage could be used to determine the potential of nuclear-transferred oocytes with embryonic stem cells to develop to the blastocyst stage in vitro, but not to determine post-implantation viability after transfer to recipients.

Effect of holding technique and culture drop size in individual or group culture on blastocyst development after ICSI of equine oocytes with low meiotic competence.

PubMed

Choi, Y H; Love, L B; Varner, D D; Hinrichs, K

2007-11-01

The effect of medium-to-embryo ratio on blastocyst development of equine embryos from oocytes with compact cumuli was evaluated in the present experiment. In addition, two methods for holding oocytes before in vitro maturation were compared. In Experiment 1, oocytes cultured with roscovitine for 16-18h before maturation were fertilized by intracytoplasmic sperm injection and cultured individually in 2.5, 5, 10 or 50microl droplets. In Experiment 2, oocytes were either cultured with roscovitine or held in a modified M199 with 20% serum at room temperature (EH treatment) for 16-18h, then matured, fertilized and cultured in groups at 5microl medium per embryo. In Experiment 3, oocytes were held in the EH treatment, then were matured and fertilized. In Study 3.1, injected oocytes were cultured individually in drop sizes as for Experiment 1; in Study 3.2, groups of 2-7 oocytes were cultured in fixed drop sizes of 5 or 50microl. Blastocyst development rates of individually-cultured embryos were not significantly different among drop sizes in either Experiment 1 or 3 (15-29%). In Experiment 2, blastocyst rates were not significantly different between holding treatments (17-23%). In Experiment 3, for group-cultured oocytes, blastocyst development was not significantly different between 5 and 50microl drops (39 and 27%, respectively). In conclusion, compact-cumulus oocytes may be effectively held in the EH treatment before maturation, and single culture of equine embryos yields acceptable blastocyst development. The greatest blastocyst rate (39%) was obtained with group culture in a 5microl droplet.

Mutations in TUBB8 and Human Oocyte Meiotic Arrest

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feng, Ruizhi; Sang, Qing; Kuang, Yanping

BACKGROUND: We present that human reproduction depends on the fusion of a mature oocyte with a sperm cell to form a fertilized egg. The genetic events that lead to the arrest of human oocyte maturation are unknown. METHODS: We sequenced the exomes of five members of a four-generation family, three of whom had infertility due to oocyte meiosis I arrest. We performed Sanger sequencing of a candidate gene, TUBB8, in DNA samples from these members, additional family members, and members of 23 other affected families. The expression of TUBB8 and all other β-tubulin isotypes was assessed in human oocytes, earlymore » embryos, sperm cells, and several somatic tissues by means of a quantitative reverse- transcriptase-polymerase-chain-reaction assay. We evaluated the effect of the TUBB8 mutations on the assembly of the heterodimer consisting of one α-tubulin polypeptide and one β-tubulin polypeptide (α/β-tubulin heterodimer) in vitro, on microtubule architecture in HeLa cells, on microtubule dynamics in yeast cells, and on spindle assembly in mouse and human oocytes. RESULTSL: We identified seven mutations in the primate-specific gene TUBB8 that were responsible for oocyte meiosis I arrest in 7 of the 24 families. TUBB8 expression is unique to oocytes and the early embryo, in which this gene accounts for almost all the expressed β-tubulin. The mutations affect chaperone-dependent folding and assembly of the α/β-tubulin heterodimer, disrupt microtubule behavior on expression in cultured cells, alter microtubule dynamics in vivo, and cause catastrophic spindle-assembly defects and maturation arrest on expression in mouse and human oocytes. CONCLUSIONS: Lastly, TUBB8 mutations have dominant-negative effects that disrupt microtubule behavior and oocyte meiotic spindle assembly and maturation, causing female infertility.« less

Intact cell MALDI-TOF mass spectrometry on single bovine oocyte and follicular cells combined with top-down proteomics: A novel approach to characterise markers of oocyte maturation.

PubMed

Labas, Valérie; Teixeira-Gomes, Ana-Paula; Bouguereau, Laura; Gargaros, Audrey; Spina, Lucie; Marestaing, Aurélie; Uzbekova, Svetlana

2018-03-20

Intact cell MALDI-TOF mass spectrometry (ICM-MS) was adapted to bovine follicular cells from individual ovarian follicles to obtain the protein/peptide signatures (<17kDa) of single oocytes, cumulus cells (CC) and granulosa cells (GC), which shared a total of 439 peaks. By comparing the ICM-MS profiles of single oocytes and CC before and after in vitro maturation (IVM), 71 different peaks were characterised, and their relative abundance was found to vary depending on the stage of oocyte meiotic maturation. To identify these endogenous biomolecules, top-down workflow using high resolution MS/MS (TD HR-MS) was performed on the protein extracts from oocytes, CC and GC. The TD HR-MS proteomic approach allowed for: (1) identification of 386 peptide/proteoforms encoded by 194 genes; and (2) characterisation of proteolysis products likely resulting from the action of kallikreins and caspases. In total, 136 peaks observed by ICM-MS were annotated by TD HR-MS (ProteomeXchange PXD004892). Among these, 16 markers of maturation were identified, including IGF2 binding protein 3 and hemoglobin B in the oocyte, thymosins beta-4 and beta-10, histone H2B and ubiquitin in CC. The combination of ICM-MS and TD HR-MS proved to be a suitable strategy to identify non-invasive markers of oocyte quality using limited biological samples. Intact cell MALDI-TOF mass spectrometry on single oocytes and their surrounding cumulus cells, coupled to an optimised top-down HR-MS proteomic approach on ovarian follicular cells, was used to identify specific markers of oocyte meiotic maturation represented by whole low molecular weight proteins or products of degradation by specific proteases. Copyright © 2017 Elsevier B.V. All rights reserved.

Appraisal of clinical complications after 23,827 oocyte retrievals in a large assisted reproductive technology program.

PubMed

Levi-Setti, Paolo Emanuele; Cirillo, Federico; Scolaro, Valeria; Morenghi, Emanuela; Heilbron, Francesca; Girardello, Donatella; Zannoni, Elena; Patrizio, Pasquale

2018-06-01

To assess complications encountered after transvaginal oocyte retrieval procedures. Retrospective analysis. University hospital, fertility center. A total of 23,827 consecutive transvaginal oocyte retrieval procedures in 12,615 patients. Oocyte retrieval procedures performed between June 1996 and October 2016. All oocyte retrieval complications. Those requiring hospital admission for at least 24 hours were considered severe. A total of 96 patients (0.76 %) suffered complications, with hospital admission necessary for 71 patients (0.56 %). When calculated per retrieval, the overall complication rate was 0.4%, whereas 0.29% was the admission rate, with an average duration of hospital stay of 2.77 ± 2.5 days. A surgical procedure was necessary for 24 patients (0.1% per retrieval and 0.19% per patient). Multivariate analysis showed a significant correlation between complications and women age, body mass index (BMI), the number oocyte retrieved, and the mean time to complete oocyte retrieval. The incidence of complications was significantly higher for physicians who had performed <250 retrievals compared with those who had completed >250 retrievals (odds ratio 0.63, 95% confidence interval 0.40-0.99). Oocyte retrieval can be considered a safe procedure but is not without risks. The most important, identifiable, risk factors for the occurrence of complications are: [1] high number of oocytes retrieved, [2] a long duration of the procedure and mean time per oocyte retrieved, [3] inexperience of the surgeon, [4] younger patients with a lesser BMI, and [5] history of prior abdominal or pelvic surgery or pelvic inflammatory disease. NCT03282279. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Effects of vitrification on nuclear maturation, ultrastructural changes and gene expression of canine oocytes

PubMed Central

2010-01-01

Background Cryopreservation of oocytes, which is an interesting procedure to conserve female gametes, is an essential part of reproductive biotechnology. The objective of the present study was to investigate the effects of vitrification on nuclear maturation, ultrastructural changes and gene expression of canine oocytes. Methods Immature oocytes (germinal vesicles) isolated from ovaries of normal bitches (> 6 months of age) were either vitrified in open pulled straw (OPS) using 20% ethylene glycol (EG) and 20% dimethyl sulfoxide (DMSO) as vitrification solution or exposed to vitrification solution without subjected to liquid nitrogen. After warming, oocytes were investigated for nuclear maturation following in vitro maturation (IVM), ultrastructural changes using transmission electron microscopy (TEM) and gene expression using RT-PCR. Fresh immature oocytes were used as the control group. Results The rate of resumption of meiosis in vitrified-warmed oocytes (53.4%) was significantly (P < 0.05) lower than those of control (93.8%) and exposure (91.4%) groups. However, there were no statistically significant differences among groups in the rates of GV oocytes reaching the maturation stage (metaphase II, MII). The ultrastructural alterations revealed by TEM showed that cortical granules, mitochondria, lipid droplets and smooth endoplasmic reticulum (SER) were affected by vitrification procedures. RT-PCR analysis for gene expression revealed no differences in HSP70, Dnmt1, SOD1 and BAX genes among groups, whereas Bcl2 was strongly expressed in vitrified-warmed group when compared to the control. Conclusion Immature canine oocytes were successfully cryopreserved, resumed meiosis and developed to the MII stage. The information obtained in this study is crucial for the development of an effective method to cryopreserve canine oocytes for establishment of genetic banks of endangered canid species. PMID:20565987

Combined positive effect of oocyte extracts and brilliant cresyl blue stained recipient cytoplasts on epigenetic reprogramming and gene expression in buffalo nuclear transfer embryos.

PubMed

Sadeesh, E M; Fozia, Shah; Meena, Kataria

2017-04-01

This study examined the effects of buffalo oocyte extracts (BOE) on donor cells reprogramming and molecular characterisation of oocytes screened via brilliant cresyl blue (BCB) staining and comparison of gene expression profiles of developmentally important genes in blastocysts from IVF and cloned derived from BOE treated donor cells with BCB selected recipient cytoplasts. Relative abundance (RA) of OCT4 and NANOG was increased (P < 0.05) and HDAC-1, DNMT-1, and DNMT-3A decreased (P < 0.05) in extract treated cells (ETCs). This ETCs dedifferentiated into neuron-like lineage under appropriate induction condition. The RA of NASP, EEF1A1, DNMT1, ODC1 and RPS27A was increased (P < 0.05) in BCB+ oocytes, whereas ATP5A1 and S100A10 increased (P < 0.05) in BCB- oocytes. Total cell number and RA of OCT4, NANOG, SOX2, DNMT1, IGF2, IGF2R, MNSOD, GLUT1, BAX and BCL2 in cloned blastocysts derived from BCB+ oocytes with ETC more closely followed that of IVF counterparts compared to BCB+ oocytes with extract untreated cell and BCB- oocytes with ETC derived blastocysts. In conclusion, BOE influenced epigenetic reprogramming of buffalo fibroblasts making them suitable donors for nuclear transfer (NT). BCB staining can be effectively used for selection of developmentally competent oocytes for NT. The combined effects of epigenetic reprogramming of donor nuclei by BOE and higher nuclear reprogramming capacity of BCB+ oocytes improve developmentally important gene expression in cloned blastocysts. Whether these improvements have long-term effects on buffalo calves born following embryo transfer remains unknown.

Identification of novel and known oocyte-specific genes using complementary DNA subtraction and microarray analysis in three different species.

PubMed

Vallée, Maud; Gravel, Catherine; Palin, Marie-France; Reghenas, Hélène; Stothard, Paul; Wishart, David S; Sirard, Marc-André

2005-07-01

The main objective of the present study was to identify novel oocyte-specific genes in three different species: bovine, mouse, and Xenopus laevis. To achieve this goal, two powerful technologies were combined: a polymerase chain reaction (PCR)-based cDNA subtraction, and cDNA microarrays. Three subtractive libraries consisting of 3456 clones were established and enriched for oocyte-specific transcripts. Sequencing analysis of the positive insert-containing clones resulted in the following classification: 53% of the clones corresponded to known cDNAs, 26% were classified as uncharacterized cDNAs, and a final 9% were classified as novel sequences. All these clones were used for cDNA microarray preparation. Results from these microarray analyses revealed that in addition to already known oocyte-specific genes, such as GDF9, BMP15, and ZP, known genes with unknown function in the oocyte were identified, such as a MLF1-interacting protein (MLF1IP), B-cell translocation gene 4 (BTG4), and phosphotyrosine-binding protein (xPTB). Furthermore, 15 novel oocyte-specific genes were validated by reverse transcription-PCR to confirm their preferential expression in the oocyte compared to somatic tissues. The results obtained in the present study confirmed that microarray analysis is a robust technique to identify true positives from the suppressive subtractive hybridization experiment. Furthermore, obtaining oocyte-specific genes from three species simultaneously allowed us to look at important genes that are conserved across species. Further characterization of these novel oocyte-specific genes will lead to a better understanding of the molecular mechanisms related to the unique functions found in the oocyte.

Mutations in TUBB8 and Human Oocyte Meiotic Arrest

DOE PAGES

Feng, Ruizhi; Sang, Qing; Kuang, Yanping; ...

2016-01-21

BACKGROUND: We present that human reproduction depends on the fusion of a mature oocyte with a sperm cell to form a fertilized egg. The genetic events that lead to the arrest of human oocyte maturation are unknown. METHODS: We sequenced the exomes of five members of a four-generation family, three of whom had infertility due to oocyte meiosis I arrest. We performed Sanger sequencing of a candidate gene, TUBB8, in DNA samples from these members, additional family members, and members of 23 other affected families. The expression of TUBB8 and all other β-tubulin isotypes was assessed in human oocytes, earlymore » embryos, sperm cells, and several somatic tissues by means of a quantitative reverse- transcriptase-polymerase-chain-reaction assay. We evaluated the effect of the TUBB8 mutations on the assembly of the heterodimer consisting of one α-tubulin polypeptide and one β-tubulin polypeptide (α/β-tubulin heterodimer) in vitro, on microtubule architecture in HeLa cells, on microtubule dynamics in yeast cells, and on spindle assembly in mouse and human oocytes. RESULTSL: We identified seven mutations in the primate-specific gene TUBB8 that were responsible for oocyte meiosis I arrest in 7 of the 24 families. TUBB8 expression is unique to oocytes and the early embryo, in which this gene accounts for almost all the expressed β-tubulin. The mutations affect chaperone-dependent folding and assembly of the α/β-tubulin heterodimer, disrupt microtubule behavior on expression in cultured cells, alter microtubule dynamics in vivo, and cause catastrophic spindle-assembly defects and maturation arrest on expression in mouse and human oocytes. CONCLUSIONS: Lastly, TUBB8 mutations have dominant-negative effects that disrupt microtubule behavior and oocyte meiotic spindle assembly and maturation, causing female infertility.« less

Effects of ghrelin on activation of Akt1 and ERK1/2 pathways during in vitro maturation of bovine oocytes.

PubMed

Chouzouris, Thomas-Markos; Dovolou, Eleni; Krania, Fotini; Pappas, Ioannis S; Dafopoulos, Konstantinos; Messinis, Ioannis E; Anifandis, George; Amiridis, Georgios S

2017-04-01

The purpose of this study was to investigate the possible molecular pathways through which ghrelin accelerates in vitro oocyte maturation. Bovine cumulus-oocyte complexes (COCs), after 18 or 24 h maturation in the absence or the presence of 800 pg ml-1 of acylated ghrelin were either assessed for nuclear maturation or underwent in vitro fertilization in standard media and putative zygotes were cultured in vitro for 8 days. In a subset of COCs the levels of phosphorylated Akt1 and ERK1/2 (MAPK1/3) were assessed at the 0th, 6th, 10th, 18th and 24th hours of in vitro maturation (IVM). At 18 and 24 h no difference existed in the proportion of matured oocytes in the ghrelin-treated group, while in the control group more (P < 0.05) matured oocyte were found at 24 h. Oocyte maturation for 24 h in the presence of ghrelin resulted in substantially reduced (P < 0.05) blastocyst yield(16.3%) in comparison with that obtained after 18 h (30.0%) or to both control groups (29.3% and 26.9%, for 18 and 24 h in maturation, respectively). Ghrelin-treated oocytes expressed lower Akt1 phosphorylation rate at the 10th hour of IVM, and higher ERK1/2 at the 6th and 10th hours of IVM compared with controls. In cumulus cells, at the 18th and 24th hours of IVM Akt1 phosphorylation rate was higher in ghrelin-treated oocytes. Our results imply that ghrelin acts in a different time-dependent manner on bovine oocytes and cumulus cells modulating Akt1 and ERK1/2 phosphorylation, which brings about acceleration of the oocyte maturation process.

Deoxynivalenol exposure induces autophagy/apoptosis and epigenetic modification changes during porcine oocyte maturation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, Jun; Wang, Qiao-Chu; Zhu, Cheng-Cheng

Deoxynivalenol (DON) is a widespread trichothecene mycotoxin which contaminates agricultural staples and elicits a complex spectrum of toxic effects on humans and animals. It has been shown that DON impairs oocyte maturation, reproductive function and causes abnormal fetal development in mammals; however, the mechanisms remain unclear. In the present study, we investigate the possible reasons of the toxic effects of DON on porcine oocytes. Our results showed that DON significantly inhibited porcine oocyte maturation and disrupted meiotic spindle by reducing p-MAPK protein level, which caused retardation of cell cycle progression. In addition, up-regulated LC3 protein expression and aberrant Lamp2, LC3more » and mTOR mRNA levels were observed with DON exposure, together with Annexin V-FITC staining assay analysis, these results indicated that DON treatment induced autophagy/apoptosis in porcine oocytes. We also showed that DON exposure increased DNA methylation level in porcine oocytes through altering DNMT3A mRNA levels. Histone methylation levels were also changed showing with increased H3K27me3 and H3K4me2 protein levels, and mRNA levels of their relative methyltransferase genes, indicating that epigenetic modifications were affected. Taken together, our results suggested that DON exposure reduced porcine oocytes maturation capability through affecting cytoskeletal dynamics, cell cycle, autophagy/apoptosis and epigenetic modifications. - Highlights: • DON exposure disrupted meiotic spindle by reducing p-MAPK expression. • DON exposure caused retardation of cell cycle progression in porcine oocytes. • DON triggered autophagy and early-apoptosis in porcine oocytes. • DON exposure led to aberrant epigenetic modifications in porcine oocytes.« less

[Recovery and light microscopic evaluation of follicular oocytes of swine and relationship between the degeneration rate of oocytes and the estrus phase].

PubMed

Schnurrbusch, U; Schmette, C; Elze, K

1990-10-01

Cumulus-oocyte complexes were recovered from 25 gilts by aspiration of follicular fluid or cutting of follicles from all Graafian follicles of greater than or equal to 3 mm in diameter during diestrus, proestrus or estrus. In 5 gilts the oocytes were collected post ovulation by flushing of oviducts. The recovery rate of follicular oocytes differed between 75.5% during the late diestrus (days 13-17) and 43.5% during the proestrus (days 18-21). During the proestrus and on day 1 of the estrus the recovery of oocytes was more difficult as a result of the higher viscosity of follicular fluid and the mucification of cumulus-oocyte complexes. The degeneration rate of oocytes was high during the diestrus with a peak at the time of regression of corpora lutea. From diestrus to the estrus the degeneration rate decreased. Following degeneration rates were found in the oocytes during the cycle: days 7-12: 38.8%, days 13-17: 50.0%, days 18-21: 29.6%, day 1 of the estrus: 10.8%, day 2 of the estrus ante ovulation: 11.8%, day 2 of the estrus post ovulation: 6.2%. Signs of degeneration were: Loss of cumulus cells (during diestrus and proestrus), damaged zona pellucida, enlargement of perivitelline space, deformation of oocyte, alteration of structure of the ooplasm, diameter of vitellus less than 100 microns. It was concluded that the selection of dominant follicles takes place in pigs during a long time of the cycle, especially during the diestrus. There were not any indications of a 2-wave hypothesis of follicular growth during the cycle in pig.

Activin Decoy Receptor ActRIIB:Fc Lowers FSH and Therapeutically Restores Oocyte Yield, Prevents Oocyte Chromosome Misalignments and Spindle Aberrations, and Increases Fertility in Midlife Female SAMP8 Mice.

PubMed

Bernstein, Lori R; Mackenzie, Amelia C L; Lee, Se-Jin; Chaffin, Charles L; Merchenthaler, István

2016-03-01

Women of advanced maternal age (AMA) (age ≥ 35) have increased rates of infertility, miscarriages, and trisomic pregnancies. Collectively these conditions are called "egg infertility." A root cause of egg infertility is increased rates of oocyte aneuploidy with age. AMA women often have elevated endogenous FSH. Female senescence-accelerated mouse-prone-8 (SAMP8) has increased rates of oocyte spindle aberrations, diminished fertility, and rising endogenous FSH with age. We hypothesize that elevated FSH during the oocyte's FSH-responsive growth period is a cause of abnormalities in the meiotic spindle. We report that eggs from SAMP8 mice treated with equine chorionic gonadotropin (eCG) for the period of oocyte growth have increased chromosome and spindle misalignments. Activin is a molecule that raises FSH, and ActRIIB:Fc is an activin decoy receptor that binds and sequesters activin. We report that ActRIIB:Fc treatment of midlife SAMP8 mice for the duration of oocyte growth lowers FSH, prevents egg chromosome and spindle misalignments, and increases litter sizes. AMA patients can also have poor responsiveness to FSH stimulation. We report that although eCG lowers yields of viable oocytes, ActRIIB:Fc increases yields of viable oocytes. ActRIIB:Fc and eCG cotreatment markedly reduces yields of viable oocytes. These data are consistent with the hypothesis that elevated FSH contributes to egg aneuploidy, declining fertility, and poor ovarian response and that ActRIIB:Fc can prevent egg aneuploidy, increase fertility, and improve ovarian response. Future studies will continue to examine whether ActRIIB:Fc works via FSH and/or other pathways and whether ActRIIB:Fc can prevent aneuploidy, increase fertility, and improve stimulation responsiveness in AMA women.

Effects of various combinations of cryoprotectants and cooling speed on the survival and further development of mouse oocytes after vitrification

PubMed Central

Cha, Soo Kyung; Kim, Bo Yeun; Kim, Mi Kyung; Kim, You Shin; Lee, Woo Sik

2011-01-01

Objective The objectives of this study were to analyze efficacy of immature and mature mouse oocytes after vitrification and warming by applying various combinations of cryoprotectants (CPAs) and/or super-rapid cooling using slush nitrogen (SN2). Methods Four-week old ICR female mice were superovulated for GV- and MII-stage oocytes. Experimental groups were divided into two groups. Ethylene glycol (EG) only group: pre-equilibrated with 1.5 M EG for 2.5 minutes and then equilibrated with 5.5 M EG and 1.0 M sucrose for 20 seconds. EG+dimethylsulfoxide (DMSO) group: pre-equilibrated with 1.3 M EG+1.1 M DMSO for 2.5 minutes and equilibrated with 2.7 M EG+2.1 M DMSO+0.5 M sucrose for 20 seconds. The oocytes were loaded onto grids and plunged into SN2 or liquid nitrogen (LN2). Stored oocytes were warmed by a five-step method, and then their survival, maturation, cleavage, and developmental rates were observed. Results The EG only and EG+DMSO groups showed no significant difference in survival of immature oocytes vitrified after warming. However, maturation and cleavage rates after conventional insemination were greater in the EG only group than in the EG+DMSO group. In mature oocytes, survival, cleavage, and blastocyst formation rates after warming showed no significant difference when EG only or EG+DMSO was applied. Furthermore, cleavage and blastocyst formation rates of MII oocytes vitrified using SN2 were increased in both the EG only and EG+DMSO groups. Conclusion A combination of CPAs in oocyte cryopreservation could be formulated according to the oocyte stage. In addition, SN2 may improve the efficiency of vitrification by reducing cryoinjury. PMID:22384414

Enhanced polarizing microscopy as a new tool in aneuploidy research in oocytes.

PubMed

Shen, Ying; Betzendahl, Ilse; Tinneberg, Hans-Rudolf; Eichenlaub-Ritter, Ursula

2008-03-12

Chromosomal non-disjunction in female meiosis gives rise to reduced fertility and trisomy in humans. Human oocytes, especially from aged women, appear especially susceptible to non-disjunction. The oocyte spindle is crucial for high fidelity of chromosome segregation at meiotic divisions, and alterations in spindle morphology are therefore indicators of adverse conditions during oocyte development that may result in meiotic aneuploidy. In the past, oocytes had to be fixed for spindle analysis, precluding direct non-invasive identification of aneugens and adverse maturation conditions that affect spindle integrity and chromosome behaviour. Aneuploidy research for detection of spindle aberrations was therefore mainly focused on in vivo or in vitro exposed, fixed animal oocytes or cytogenetic analysis of spread oocytes. Orientation independent enhanced polarizing microscopy with nearly circularly polarized light and electronically controlled liquid crystal compensator optics is a new tool to study spindle morphology non-invasively in vivo for qualitative as well as quantitative analysis. Image generation by polarization microscopy depends on the intrinsic optical properties of the spindle with its paracrystalline microtubule lattice. When polarized light passes through such a lattice it induces a splitting of the beam and shift in the plane of vibration and retardation of light (termed birefringence and retardance). Studies of animal oocytes and follicle-cell denuded human oocytes fertilized by intracytoplasmic sperm injection for assisted conception have demonstrated the safety and efficacy of enhanced polarization microscopy. The method can be employed in aneuploidy research for non-invasive dose-response studies to detect spindle aberrations, for instance, in combination with cytogenetic analysis. Due to the non-invasive nature of the technique it may be employed in routine analysis of human oocytes to assess risks by lifestyle factors, and occupational and adverse environmental exposures.

Estimation of second polar body retention rate after conventional insemination and intracytoplasmic sperm injection: in vitro observations from more than 5000 human oocytes.

PubMed

Porter, Richard; Han, Taer; Tucker, Michael J; Graham, James; Liebermann, Juergen; Sills, E Scott

2003-09-01

Tripronucleate (3pn) development after conventional insemination (CONV) or ICSI was analyzed to estimate the rate of second polar body retention giving rise to 3pn formation. Data from 453 consecutive IVF cycles were reviewed during a 6-month period. Mature oocytes were monitored in ICSI (n = 3195) and CONV (n = 2274) groups by fertilization assessment 16-18 h post-insemination. Ovulation induction protocols and in vitro culture conditions remained constant during the study interval. Normal (2pn) fertilization occurred in 74.2% and 70.5% for CONV and ICSI groups, respectively (p < 0.003). 1pn formation was observed in 4.5% of CONV oocytes, and 2.5% of ICSI oocytes (p < 0.001); 3pn formation was 8.1% in the CONV group, and 2.5% in the ICSI group (p < 0.0001). We observed 4pn formation in 0.4% of oocytes in the CONV group, but in only 0.04% of oocytes fertilized with ICSI (p < 0.007). Cellular degeneration occurred in 2.4% of oocytes inseminated conventionally, and in 3.5% of oocytes fertilized by ICSI (p = 0.02). Maternal age did not impact pronuclear status. We found the 3pn formation rate after ICSI to be approximately one-third that observed in the CONV group. Extrapolating the ICSI data to the CONV data, it may be inferred that 2.5% of 3pn development after CONV was due to second polar body retention. This suggests that 5.6% of CONV oocytes showed dispermic fertilization. Decreasing oocyte quality with increasing maternal age had no apparent influence on any of the fertilization outcomes.

Genetic influences on ovulation of primary oocytes in LT/Sv strain mice.

PubMed

Everett, Clare A; Auchincloss, Catherine A; Kaufman, Matthew H; Abbott, Catherine M; West, John D

2004-11-01

A high proportion of LT/Sv strain oocytes arrest in meiotic metaphase I (MI) and are ovulated as diploid primary oocytes rather than haploid secondary oocytes. (Mus musculus castaneus x LT/SvKau)F1 x LT/SvKau backcross females were analysed for the proportion of oocytes that arrested in MI and typed by PCR for a panel of microsatellite DNA sequences (simple sequence repeat polymorphisms) that differed between strain LT/SvKau and M. m. castaneus. This provided a whole genome scan of 86 genetic markers distributed over all 19 autosomes and the X chromosome, and revealed genetic linkage of the MI arrest phenotype to markers on chromosomes 1 and 9. Identification of these two chromosomal regions should facilitate the identification of genes involved in mammalian oocyte maturation and the control of meiosis.

Influence of follicular fluid and cumulus cells on oocyte quality: clinical implications.

PubMed

Da Broi, M G; Giorgi, V S I; Wang, F; Keefe, D L; Albertini, D; Navarro, P A

2018-03-02

An equilibrium needs to be established by the cellular and acellular components of the ovarian follicle if developmental competence is to be acquired by the oocyte. Both cumulus cells (CCs) and follicular fluid (FF) are critical determinants for oocyte quality. Understanding how CCs and FF influence oocyte quality in the presence of deleterious systemic or pelvic conditions may impact clinical decisions in the course of managing infertility. Given that the functional integrities of FF and CCs are susceptible to concurrent pathological conditions, it is important to understand how pathophysiological factors influence natural fertility and the outcomes of pregnancy arising from the use of assisted reproduction technologies (ARTs). Accordingly, this review discusses the roles of CCs and FF in ensuring oocyte competence and present new insights on pathological conditions that may interfere with oocyte quality by altering the intrafollicular environment.

In vitro embryos production after oocytes treatment with forskolin.

PubMed

Paschoal, Daniela Martins; Maziero, Rosiára Rosária Dias; Sudano, Mateus José; Guastali, Midyan Daroz; Vergara, Luis Eduardo; Crocomo, Letícia Ferrari; Lima-Neto, João Ferreira de; Magalhães, Luis Carlos Oña; Monteiro, Bianca Andriolo; Rascado, Tatiana da Silva; Martins, Alício; Leal, Claudia Lima Verde; Landim-Alvarenga, Fernanda da Cruz

2016-04-01

The inhibition of nuclear maturation allows time for the oocyte to accumulate molecules that are important for embryonic development. Thus, the objective of this work was to evaluate the effect of blocking oocyte meiosis with the addition of forskolin, an efficient inhibitor of nuclear maturation, in in vitro maturation (IVM) medium. Forskolin was added to the IVM medium for 6 h at concentrations of 0.1 mM, 0.05 mM or 0.025 mM, then the oocytes were allowed to mature in drug-free medium for 18 h. The oocytes were assessed for the stage of nuclear maturation, the activity and distribution of mitochondria, oocyte ultrastructure, the number of viable cells and the apoptosis rate. After forskolin treatment, the oocytes were fertilized in vitro and cultured for 7 days. On day 7, the blastocyst rate, the ultrastructure, the number of intact cells and the apoptosis rate of the blastocysts were measured. No differences were observed for the stage of nuclear maturation of the oocyte, the mitochondrial activity and distribution, the blastocyst rate or total number of intact cells. However, a higher rate of apoptosis was observed in the blastocysts produced from oocytes blocked for 6 h with the higher concentration of forskolin (P < 0.05). We conclude that all the experimental groups reached the MII stage after the addition of forskolin and that the highest concentration of forskolin caused cellular degeneration without harming embryo production on the 7th day.

Superovulation induction in the house musk shrew (Suncus murinus).

PubMed

Matsuzaki, T; Matsuzaki, K; Yokoyama, M; Yamada, S; Saito, M

1997-07-01

The number of ovulated oocytes in the adult house musk shrews was examined by natural mating. The positive rate of ovulation was 83.3%, and the mean number of ovulated oocytes was 4.4 +/- 1.9 (Mean +/- SD). The induction of superovulation was examined by administering either pregnant mare's serum gonadotropin (PMSG) or human chorionic gonadotropin (hCG), exogenous gonadotropin, to house musk shrews. As a result, the number of ovulated oocytes were within the number of oocytes ovulated spontaneously. The method of superovulation induction by administering both PMSG and hCG to house musk shrews was investigated. In the group intraperitoneally with 7.5 i.u. of PMSG followed by 7.5 i.u. of hCG 48 hr later, the positive rate of ovulation was as high as 94.6% and the mean number of ovulated oocytes was 11.7 +/- 13.4. Moreover, in 15 out of these 35 animals positive for ovulation, 10 oocytes or more were observed and the mean number of ovulated oocytes was 21.0 +/- 16.5, showing the superovulatory response. In the group of 5.0 i.u. PMSG and 5.0 i.u. hCG injected at an interval of 72 hr, every animal was induced to ovulate and the mean number of ovulated oocytes was 41.3 +/- 19.9. Thus, the injection of PMSG and hCG at a longer interval increased the number of superovulated oocytes. Furthermore, 97.5% of eggs recovered from superovulating animals contained cumulus cells.

Toxic effects and possible mechanisms of hydrogen sulfide and/or ammonia on porcine oocyte maturation in vitro.

PubMed

Yang, Lei-Lei; Zhao, Yong; Luo, Shi-Ming; Ma, Jun-Yu; Ge, Zhao-Jia; Shen, Wei; Yin, Shen

2018-03-15

Previous studies suggest that hydrogen sulfide (H 2 S) and ammonia (NH 3 ) are two major air pollutants which can cause damage to porcine health. However, the mechanisms underlying toxic effects of these compounds on porcine oocyte maturation are not clear. To clarify the mechanism, we evaluated the oocyte quality by detecting some events during oocytes maturation. In our study, porcine oocytes were cultured with different concentrations of Na 2 S and/or NH 4 Cl in vitro and the rate of the first polar body extrusion decreased significantly. Also, actin filament was seriously disrupted to damage the cytoskeleton which resulted in reduced rate of oocyte maturation. We explored the reactive oxygen species (ROS) generation and found that the ROS level was increased significantly after Na 2 S treatment but not after NH 4 Cl treatment. Moreover, early stage apoptosis rate was significantly increased and autophagy protein LC3 B expression level was higher in oocytes treated with Na 2 S and/or NH 4 Cl, which might be caused by ROS elevation. Additionally, exposure to Na 2 S and/or NH 4 Cl also caused ROS generation and early apoptosis in cumulus cells, which might further affect oocyte maturation in vitro. In summary, our data suggested that exposure to H 2 S and/or NH 3 decreased porcine oocyte maturation in vitro, which might be caused by actin disruption, ROS generation, early apoptosis and autophagy. Copyright © 2017 Elsevier B.V. All rights reserved.

Stereological estimation of ovarian oocyte volume, surface area and number: application on mice treated with nandrolone decanoate.

PubMed

Karbalay-Doust, Saied; Noorafshan, Ali

2012-07-05

Changes in the number and size of oocytes can lead to fertilization problems. The present study aimed to evaluate the number, volume, and surface area of oocytes in healthy as well as nandrolone decanoate-treated (ND) mice using stereological methods. Five control mice received vehicle, and five ND-treated mice received ND. Using the 'isotropic Cavalieri' design', the ovary was sectioned. The volume of the ovary (cortex and medulla) was estimated. The oocytes' volume and surface area were estimated using the invariator. The number of the oocytes was estimated using an optical disector. The volumes of the ovary, cortex, and medulla decreased ~50% in the ND-treated mice. The mean number (coefficient of variation) of preantral, antral, and atretic oocytes in the control ovary were 1,690 (0.29), 2,100 (0.52), and 3,900 (0.2), respectively, which decreased ~54%, ~87%, and ~91%, respectively in the ND-treated animals. The mean volume (coefficient of variation) of the preantral, antral, and atretic oocytes were 86,000 (0.27), 110,000 (0.48), and 27,000 (0.33) μm³, respectively. The mean surface area (coefficient of variation) of the three types of oocytes were 9,000 (0.24), 9,900 (0.28), and 4,700 (0.21) μm², respectively. These parameters remained unchanged in the ND-treated mice. ND induces reduction in the number of oocytes, but not in the volume or the surface area.

WAVE2 regulates meiotic spindle stability, peripheral positioning and polar body emission in mouse oocytes.

PubMed

Sun, Shao-Chen; Xu, Yong-Nan; Li, Ying-Hua; Lee, Seung-Eun; Jin, Yong-Xun; Cui, Xiang-Shun; Kim, Nam-Hyung

2011-06-01

During oocyte meiotic maturation, meiotic spindles form in the central cytoplasm and then migrate to the cortex to extrude a small polar body, forming a highly polarized cell through a process involving actin and actin-related molecules. The mechanisms underlying oocyte polarization are still unclear. The Arp2/3 complex regulates oocyte polarization but it is not known whether the WASP family of proteins, a known regulator of the Arp2/3 complex, is involved in this context. In the present study, the role of WASP family member WAVE2 in mouse oocyte asymmetric division was investigated. (1) WAVE2 mRNA and protein were detected during mouse oocyte meiosis. (2) siRNA-mediated and antibody-mediated disruption of WAVE2 resulted in the failure of chromosome congression, spindle formation, spindle positioning and polar body extrusion. (3) WAVE2 regulated actin-driven chromosome migration since chromosomes were arrested in the central cytoplasm by WAVE2 RNAi in the absence of microtubules. (4) Localization of γ-tubulin and MAPK was disrupted after RNAi, confirming the effect of WAVE2 on spindle formation. (5) Actin cap and cortical granule-free domain (CGFD) formation was also disrupted, further confirming the failure of oocyte polarization. Our data suggest that WAVE2 regulates oocyte polarization by regulating meiotic spindle, peripheral positioning, probably via an actin-mediated pathway, and is involved in polar body emission during mouse oocyte meiotic maturation.

Gamete rescue in the African black rhinoceros (Diceros bicornis).

PubMed

Stoops, M A; O'Brien, J K; Roth, T L

2011-10-15

Mortality rates are high among captive African black rhinoceroses (Diceros bicornis), due to increased susceptibility to disease. The ability to rescue genetic material from individuals that die unexpectedly represents a practical approach to assist ex situ conservation efforts. The objectives of the present study were to attempt postmortem oocyte recovery from ovaries of African black rhinoceroses (N = 6) and to test the efficacy of equine protocols for rhinoceros oocyte IVM and IVF using cryopreserved rhinoceros sperm. The interval from ovary removal to oocyte recovery was 25.3 ± 13.9 h (mean ± SD). Ovaries were transported at 4 °C or 22 °C and effects of temperature on postmortem oocyte competence was evaluated. Numbers of oocytes collected per female averaged 15.8 ± 6.9. In total, 95 oocytes were recovered. Of these, 85 were inseminated using homologous sperm and 10 were inseminated using heterologous sperm. Overall, substantial numbers of viable oocytes were retrieved from African black rhinoceros ovaries 1 to 2 days postmortem from ovaries stored at ambient temperature. A proportion of these oocytes matured and underwent penetration and fertilization by heterologous or homologous frozen-thawed rhinoceros sperm. The reproductive competence of postmortem oocytes was further demonstrated by development of a single two-cell embryo. Despite the need for further refinements, gamete rescue in the rhinoceros has promise for producing rhinoceros embryos, as well as testing sperm functions in vitro. Copyright © 2011 Elsevier Inc. All rights reserved.

SIRT1 signalling protects mouse oocytes against oxidative stress and is deregulated during aging.

PubMed

Di Emidio, Giovanna; Falone, Stefano; Vitti, Maurizio; D'Alessandro, Anna Maria; Vento, Marilena; Di Pietro, Cinzia; Amicarelli, Fernanda; Tatone, Carla

2014-09-01

Is SIRT1 involved in the oxidative stress (OS) response in mouse oocytes? SIRT1 plays a pivotal role in the adaptive response of mouse germinal vesicle (GV) oocytes to OS and promotes a signalling cascade leading to up-regulation of the MnSod gene. OS is known to continuously threaten acquisition and maintenance of oocyte developmental potential during in vivo processes and in vitro manipulations. Previous studies in somatic cells have provided strong evidence for the role of SIRT1 as a sensor of the cell redox state and a protector against OS and aging. GV oocytes obtained from young (4-8 weeks) and reproductively old (48-52 weeks) CD1 mice were blocked in the prophase stage by 0.5 µM cilostamide. Groups of 30 oocytes were exposed to 25 µM H2O2 and processed following different times for the analysis of intracellular localization of SIRT1 and FOXO3A, and evaluation of Sirt1, miRNA-132, FoxO3a and MnSod gene expression. Another set of oocytes was cultured in the presence or absence of the SIRT1-specific inhibitor Ex527, and exposed to H2O2 in order to assess the involvement of SIRT1 in the activation of a FoxO3a-MnSod axis and ROS detoxification. In the last part of this study, GV oocytes were maturated in vitro in the presence of different Ex527 concentrations (0, 2.5, 5, 10, 20 µM) and assessed for maturation rates following 16 h. Effects of Ex527 on spindle morphology and ROS levels were also evaluated. SIRT1 and FOXO3A intracellular distribution in response to OS was investigated by immunocytochemistry. Real-time RT-PCR was employed to analyse Sirt1, miR-132, FoxO3a and MnSod gene expression. Reactive oxygen species (ROS) production was evaluated by in vivo measurement of carboxy-H2DCF diacetate labelling. Spindle and chromosomal distribution in in vitro matured oocytes were analysed by immunocytochemistry and DNA fluorescent labelling, respectively. Specific changes in the intracellular localization of SIRT1 and up-regulation of Sirt1 gene were detected in mouse oocytes in response to OS. Moreover, increased intracellular ROS were observed when SIRT1 activity was inhibited by Ex527. In aged oocytes Sirt1 was expressed more than in young oocytes but SIRT1 protein was undetectable. Upon OS, significant changes in miR-132 micro-RNA, a validated Sirt1 modulator, were observed. A negative correlation between Sirt1 mRNA and miR-132 levels was observed when young oocytes exposed to OS were compared with young control oocytes, and when aged oocytes were compared with young control oocytes. FoxO3a and MnSod transcripts were increased upon OS with the same kinetics as Sirt1 transcripts, and up-regulation of MnSod gene was prevented by oocyte treatment with Ex527, indicating that SIRT1 acts upstream to the FoxO3a-MnSod axis. Finally, the results of the in vitro maturation assay suggested that SIRT1 might be involved in oocyte maturation by regulating the redox state and ensuring normal spindle assembly. The main limitation of this study was the absence of direct quantification of SIRT1 enzymatic activity due to the lack of an appropriately sensitive method. The present findings may provide a valuable background for studying the regulation of SIRT1 during oogenesis and its relevance as a sensor of oocyte redox state and energy status. The antioxidant response orchestrated by SIRT1 in oocytes seems to decrease with aging. This suggests that SIRT1 could be an excellent pharmacological target for improving oocyte quality and IVF outcome in aging or aging-like diseases. The work was supported by the Ministero dell'Università e della Ricerca Scientifica (MIUR) to C.T., F.A., C.D., A.M.D. The authors declare no conflict of interest. © The Author 2014. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

The effects of platelet lysate on maturation, fertilization and embryo development of NMRI mouse oocytes at germinal vesicle stage.

PubMed

Pazoki, Hassan; Eimani, Hussein; Farokhi, Farah; Shahverdi, Abdol-Hossein; Tahaei, Leila Sadat

2016-04-01

Improving in vitro maturation could increase the rate of pregnancy from oocytes matured in vitro. Consequently, patients will be prevented from using gonadotropin with its related side effects. In this study, the maturation medium was enriched by platelet lysate (PL), then maturation and subsequent developments were monitored. Oocytes at germinal vesicle stage with cumulus cells (cumulus-oocyte complex) and without cumulus cells (denuded oocytes) were obtained from mature female mice. The maturation medium was enriched by 5 and 10 % PL and 5 % PL + 5 % fetal bovine serum (FBS) as experimental groups; the control groups' media consisted of 5 and 10 % FBS. After 18 h, the matured oocytes were collected and, after fertilization, subsequent development was monitored. The rates of maturation, fertilization and 2-cell embryo development for the denuded oocyte groups in experimental media 5 % PL and 5 % PL + 5 % FBS were significantly higher than those of the control groups ( P < 0.05), while the results for the cumulus-oocyte complex groups were similar between the experimental groups and control groups. The results of this study indicated that platelet lysate could improve the maturation rate in the absence of granulosa cells compared to media with FBS. This extract also had positive effects on fertilization and embryo development.

The Adverse Effects of Triptolide on the Reproductive System of Caenorhabditis elegans: Oogenesis Impairment and Decreased Oocyte Quality

PubMed Central

Ruan, Qinli; Xu, Yun; Xu, Rui; Wang, Jiaying; Hua, Yongqing; Wang, Meng; Duan, Jinao

2017-01-01

Previous studies have revealed that Triptolide damages female reproductive capacity, but the mechanism is unclear. In this study, we used Caenorhabditis elegans to investigate the effects of Triptolide on the germline and explore its possible mechanisms. Our data show that exposure for 4 h to 50 and 100 mg/L Triptolide reduced C. elegans fertility, led to depletion and inactivation of spermatids with the changes in the expression levels of related genes, and increased the number of unfertilized oocytes through damaging chromosomes and DNA damage repair mechanisms. After 24 and 48 h of the 4 h exposure to 50 and 100 mg/L Triptolide, we observed shrink in distal tip cells, an increase in the number of apoptotic cells, a decrease in the number of mitotic germ cells and oocytes in diakinesis stage, and chromatin aggregates in −1 oocytes. Moreover, expression patterns of the genes associated with mitotic germ cell proliferation, apoptosis, and oocyte quality were altered after Triptolide exposure. Therefore, Triptolide may damage fertility of nematodes by hampering the development of oocytes at different developmental stages. Alterations in the expression patterns of genes involved in oocyte development may explain the corresponding changes in oocyte development in nematodes exposed to Triptolide. PMID:28230788

Blood clots in the cumulus-oocyte complex predict poor oocyte quality and post-fertilization development.

PubMed

Ebner, T; Moser, M; Shebl, O; Sommergruber, M; Yaman, C; Tews, G

2008-06-01

Assessment of oocyte maturity and quality (morphological appearance) at the time of retrieval is difficult as the egg is obscured by a large cumulus mass that hinders adequate scoring. Since no data are available on the possible relationship between the cumulus-oocyte complex (COC) and oocyte morphology, this prospective intracytoplasmic sperm injection study was set up in 87 consecutive patients. COC were grouped according to expansion of both corona radiata and cumulus matrix. Special emphasis was placed on recording morphological anomalies of COC (inclusion of blood clots and amorphous clumps). For all mature ovae, quality was assessed and preimplantation development followed up to blastocyst stage if fertilized. The risk of not harvesting an oocyte was higher in COC with blood clots compared with normal cumulus matrices (P = 0.004). COC expansion did not allow for prediction of either nuclear status or quality of the egg. The presence of blood clots within the cumulus matrix was associated with reduced oocyte quality (dense central granulation), fertilization rate and blastocyst formation, compared with unaffected COC (P < 0.05). It may be postulated that COC showing blood inclusions derive from poor quality follicles, which has a detrimental effect on oocyte quality and further cleavage to blastocyst stage. Consequently, mechanical removal of blood clots cannot rescue the corresponding embryo.

The evolution of oocyte donation in China.

PubMed

Wang, Fang; Sun, Yingpu; Kong, Huijuan; Li, Jing; Su, Yingchun; Guo, Yihong

2010-07-01

To review the experience with and clinical outcomes for recipients of embryos from oocytes donated under different regulatory standards in China. Initially, the oocytes were provided by one of the patient's consanguineous sisters. Then, the oocytes were obtained from another patient treated with assisted reproduction techniques (ART). Presently, oocytes thus produced are cryopreserved for at least 6months before transfer. The records from all women treated with ART at First Affiliated Hospital of Zhengzhou University since 2001 were reviewed and the pregnancy rates and clinical outcomes were determined for each of the 3 periods. In the second period, the mean implantation and clinical pregnancy rates were significantly higher for the 22 oocyte recipients than for their donors. In the third period, the rates for the 56 recipients were compared with the 78 other regular ART patients fertilized with their own oocytes. There were 40 live births for 32 of the recipients over 28 cycles, and the rates of implantation and clinical pregnancy were much higher for the recipients than for the other ART patients (P<0.001). Using freshly donated eggs yields a higher pregnancy rate but there is a risk of infectious disease. Using frozen oocytes can significantly decrease this risk but implantation rates are lower. Copyright (c) 2010 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

Melatonin protects against maternal obesity-associated oxidative stress and meiotic defects in oocytes via the SIRT3-SOD2-dependent pathway.

PubMed

Han, Longsen; Wang, Haichao; Li, Ling; Li, Xiaoyan; Ge, Juan; Reiter, Russel J; Wang, Qiang

2017-10-01

Maternal obesity in humans is associated with poor outcomes across the reproductive spectrum. Emerging evidence indicates that these defects are likely attributed to factors within the oocyte. Although various molecules and pathways may contribute to impaired oocyte quality, prevention of fertility issues associated with maternal obesity is a challenge. Using mice fed a high-fat diet (HFD) as an obesity model, we document spindle disorganization, chromosome misalignment, and elevated reactive oxygen species (ROS) levels in oocytes from obese mice. Oral administration of melatonin to HFD mice not only reduces ROS generation, but also prevents spindle/chromosome anomalies in oocytes, consequently promoting the developmental potential of early embryos. Consistent with this finding, we find that melatonin supplement during in vitro maturation also markedly attenuates oxidative stress and meiotic defects in HFD oocytes. Finally, by performing morpholino knockdown and acetylation-mimetic mutant overexpression assays, we reveal that melatonin ameliorates maternal obesity-induced defective phenotypes in oocytes through the SIRT3-SOD2-dependent mechanism. In sum, our data uncover the marked beneficial effects of melatonin on oocyte quality from obese females; this opens a new area for optimizing culture system as well as fertility management. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Ultrastructural Interactions and Genotoxicity Assay of Cerium Dioxide Nanoparticles on Mouse Oocytes

PubMed Central

Courbiere, Blandine; Auffan, Mélanie; Rollais, Raphaël; Tassistro, Virginie; Bonnefoy, Aurélie; Botta, Alain; Rose, Jérôme; Orsière, Thierry; Perrin, Jeanne

2013-01-01

Cerium dioxide nanoparticles (CeO2 ENPs) are on the priority list of nanomaterials requiring evaluation. We performed in vitro assays on mature mouse oocytes incubated with CeO2 ENPs to study (1) physicochemical biotransformation of ENPs in culture medium; (2) ultrastructural interactions with follicular cells and oocytes using Transmission Electron Microscopy (TEM); (3) genotoxicity of CeO2 ENPs on follicular cells and oocytes using a comet assay. DNA damage was quantified as Olive Tail Moment. We show that ENPs aggregated, but their crystal structure remained stable in culture medium. TEM showed endocytosis of CeO2 ENP aggregates in follicular cells. In oocytes, CeO2 ENP aggregates were only observed around the zona pellucida (ZP). The comet assay revealed significant DNA damage in follicular cells. In oocytes, the comet assay showed a dose-related increase in DNA damage and a significant increase only at the highest concentrations. DNA damage decreased significantly both in follicular cells and in oocytes when an anti-oxidant agent was added in the culture medium. We hypothesise that at low concentrations of CeO2 ENPs oocytes could be protected against indirect oxidative stress due to a double defence system composed of follicular cells and ZP. PMID:24185910

Reproductive experiences of women who cryopreserved oocytes for non-medical reasons.

PubMed

Hammarberg, Karin; Kirkman, Maggie; Pritchard, Natasha; Hickey, Martha; Peate, Michelle; McBain, John; Agresta, Franca; Bayly, Chris; Fisher, Jane

2017-03-01

What are the reproductive experiences of women who cryopreserve oocytes for non-medical reasons? One in three women had been pregnant at some stage in their lives and while most still wanted to have a child or another child, very few had used their stored oocytes, predominantly because they did not want to be single parents. The number of healthy women who freeze oocytes to avoid age-related infertility is increasing. Evidence about reproductive outcomes after oocyte cryopreservation for non-medical reasons is needed to help women make informed decisions. A cross-sectional survey was carried out. Study packs which included a self-administered questionnaire were mailed by clinic staff to 193 eligible women. Women who had stored oocytes for non-medical reasons at Melbourne IVF, a private ART clinic, between 1999 and 2014 were identified from medical records and invited to complete an anonymous questionnaire about their reproductive histories and experience of oocyte cryopreservation. A total of 10 survey packs were returned to the clinic marked 'address unknown'. Of the 183 potential respondents, 96 (53%) returned the questionnaire. One respondent provided only free-text comments, thus data from 95 respondents were compiled. The mean age at the time of freezing oocytes was 37.1 years (SD ± 2.6, range: 27-42) and the average number of oocytes stored was 14.2 (SD ± 7.9, range: 0-42); 2% had attempted to store oocytes but had none suitable for freezing, 24% had stored <8 oocytes, 35% had 8-15, 25% had 16-23 and 14% had stored >23 oocytes. About one-third of respondents (34%) had been pregnant at some point in their lives. Six women (6%) had used their stored oocytes and three of them had given birth as a result. The main reason for not using stored oocytes was not wanting to be a single parent. Of the 87 (91%) women who still had oocytes stored, 21% intended to use them while 69% indicated that their circumstances would determine usage. The mean number of children respondents would ideally have liked to have was significantly higher than the number of children they expected to have (2.11 versus 1.38, P < 0.001). The limitations are inherent to any anonymously completed questionnaire: participation bias, missing data and the possibility that some questions or response alternatives may have been ambiguous. The findings add to the very limited evidence about the reproductive outcomes experienced by women who freeze oocytes for non-medical reasons and can be used to help women make informed decisions about whether to store oocytes. The study was funded by Melbourne IVF. K.H. has received honoraria from Merck-Serono, J.M. is a clinician at Melbourne IVF, F.A. is a Melbourne IVF employee, J.F. is supported by a Monash Professorial Fellowship and the Jean Hailes Professorial Fellowship which receives funding from the L and H Hecht Trust, managed by Perpetual Trustees Pty Ltd. M.K., N.P., M.H., M.P. and C.B. have no competing interests. Not applicable. © The Author 2017. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

Combined multiphoton imaging and automated functional enucleation of porcine oocytes using femtosecond laser pulses

NASA Astrophysics Data System (ADS)

Kuetemeyer, Kai; Lucas-Hahn, Andrea; Petersen, Bjoern; Lemme, Erika; Hassel, Petra; Niemann, Heiner; Heisterkamp, Alexander

2010-07-01

Since the birth of ``Dolly'' as the first mammal cloned from a differentiated cell, somatic cell cloning has been successful in several mammalian species, albeit at low success rates. The highly invasive mechanical enucleation step of a cloning protocol requires sophisticated, expensive equipment and considerable micromanipulation skill. We present a novel noninvasive method for combined oocyte imaging and automated functional enucleation using femtosecond (fs) laser pulses. After three-dimensional imaging of Hoechst-labeled porcine oocytes by multiphoton microscopy, our self-developed software automatically identified the metaphase plate. Subsequent irradiation of the metaphase chromosomes with the very same laser at higher pulse energies in the low-density-plasma regime was used for metaphase plate ablation (functional enucleation). We show that fs laser-based functional enucleation of porcine oocytes completely inhibited the parthenogenetic development without affecting the oocyte morphology. In contrast, nonirradiated oocytes were able to develop parthenogenetically to the blastocyst stage without significant differences to controls. Our results indicate that fs laser systems have great potential for oocyte imaging and functional enucleation and may improve the efficiency of somatic cell cloning.

Pregnancy and delivery after in vitro maturation of naked ICSI-GV oocytes with GH and transfer of a frozen thawed blastocyst: case report.

PubMed

Menezo, Yves J R; Nicollet, Bernard; Rollet, Jacques; Hazout, André

2006-01-01

To determine if GV oocytes, collected at the time of ICSI, can be matured in vitro and rescued for therapeutic treatment. A patient for whom all the collected oocytes at the GV stage after a classical COH protocol were matured in vitro with GH. All the naked oocytes were matured in a culture medium (ISM2) containing 15% patient serum +1.6 units of GH (Saizen) per millilitre. Oocytes were incubated overnight at 37 degrees C. The MII oocytes obtained were micro-injected. A fresh transfer was performed and a supernumerary blastocyst was frozen. The patient was pregnant and delivered a healthy girl after transfer of the frozen/thawed blastocyst. The baby girl is now 2 years old. In vitro maturation with GH allows rescuing naked GV oocytes collected at the time of ICSI. GH action does not pass through the cumulus cells. According to the possible lack of synchrony between the embryo and the uterus, we recommend to freeze the embryos obtained and to replace them in a controlled cycle.

Repair and recombination of X-irradiated plasmids in Xenopus laevis oocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sweigert, S.E.; Carroll, D.

1990-11-01

Plasmid DNA substrates were X-irradiated and injected into the nuclei of Xenopus laevis oocytes. After incubation for 20 h, DNA was recovered from the oocytes and analyzed simultaneously for repair and for intermolecular homologous recombination by electrophoresis and bacterial transformation. Oocyte-mediated repair of DNA strand breaks was observed with both methods. Using a repair-deficient mutant Escherichia coli strain and its repair-proficient parent as hosts for the transformation assay, we also demonstrated that oocytes repaired oxidative-type DNA base damage induced by X-rays. X-irradiation of a circular DNA stimulated its potential to recombine with a homologous linear partner. Recombination products were detectedmore » directly by Southern blot hybridization and as bacterial transformant clones expressing two antibiotic resistance markers originally carried separately on the two substrates. The increase in recombination was dependent on X-ray dose. There is some suggestion that lesions other than double-strand breaks contribute to the stimulation of oocyte-mediated homologous recombination. In summary, oocytes have considerable capacity to repair X-ray-induced damage, and some X-ray lesions stimulate homologous recombination in these cells.« less

Cytoskeletal changes in oocytes and early embryos during in vitro fertilization process in mice.

PubMed

Gumus, E; Bulut, H E; Kaloglu, C

2010-02-01

The cytoskeleton plays crucial roles in the development and fertilization of germ cells and in the early embryo development. The growth, maturation and fertilization of oocytes require an active movement and a correct localization of cellular organelles. This is performed by the re-organization of microtubules and actin filaments. Therefore, the aim of the present study was to determine the changes in cytoskeleton during in vitro fertilization process using appropriate immunofluorescence techniques. While the chromatin content was found to be scattered throughout the nucleus during the oocyte maturation period, it was seen only around nucleolus following the completion of the maturation. Microtubules, during oocyte maturation, were regularly distributed throughout the ooplasm which was then localized in the subcortical region of oocytes. Similarly microfilaments were scattered throughout the ooplasm during the oocyte maturation period whereas they were seen in the subcortical region around the polar body and above the meiotic spindle throughout the late developmental stages. In conclusion, those changes occurred in microtubules and microfilaments might be closely related to the re-organization of the genetic material during the oocyte maturation and early embryo development.

A possible role of progesterone receptor in mouse oocyte in vitro fertilization regulated by norethisterone and its reduced metabolite.

PubMed

Flores-Herrera, Héctor; Díaz-Cervantes, Paola; De la Mora, Gustavo; Zaga-Clavellina, Verónica; Uribe-Salas, Felipe; Castro, Ivone

2008-12-01

The contraceptive effect of the progestogen norethisterone (NET) and its main metabolites 5alpha-NET and 3beta,5alpha-NET has been demonstrated in several species, and most studies have focused on the effects of these compounds in the uterus. We previously reported that 5alpha-NET inhibits the progesterone (P(4))-induced acrosome reaction in pig and mouse spermatozoa and induces severe morphological damage in two-cell fertilized mouse oocytes. The main goal of this study was to analyze the possible role of P(4) receptor (PR) in the effects of NET and 5alpha-NET on the oocyte fertilization process. Different steroid treatments were used with or without cumulus-enclosed oocytes. It was demonstrated that NET increases the percentage of fertilized oocytes in the same manner as P(4) does, while 5alpha-NET reduces the percentage of fertilized oocytes. This effect was not reversed by P(4) in the same concentrations. A possible molecular mechanism for the effects of 5alpha-NET may be through a PR localized in the oocyte plasma membrane.

Cloned foal derived from in vivo matured horse oocytes aspirated by the short disposable needle system.

PubMed

Lee, Wonyou; Song, Kilyoung; Lee, Inhyung; Shin, Hyungdo; Lee, Byeong Chun; Yeon, Seongchan; Jang, Goo

2015-01-01

Transvaginal ultrasound-guided follicle aspiration is one method of obtaining recipient oocytes for equine somatic cell nuclear transfer (SCNT). This study was conducted: (1) to evaluate the possibility of oocyte aspiration from pre-ovulatory follicles using a short disposable needle system (14-G) by comparing the oocyte recovery rate with that of a long double lumen needle (12-G); (2) to investigate the developmental competence of recovered oocytes after SCNT and embryo transfer. The recovery rates with the short disposable needle vs. the long needle were not significantly different (47.5% and 35.0%, respectively). Twenty-six SCNT embryos were transferred to 13 mares, and one mare delivered a live offspring at Day 342. There was a perfect identity match between the cloned foal and the cell donor after analysis of microsatellite DNA, and the mitochondrial DNA of the cloned foal was identical with that of the oocyte donor. These results demonstrated that the short disposable needle system can be used to recover oocytes to use as cytoplasts for SCNT, in the production of cloned foals and for other applications in equine embryology.

Nuclear m6A reader YTHDC1 regulates alternative polyadenylation and splicing during mouse oocyte development.

PubMed

Kasowitz, Seth D; Ma, Jun; Anderson, Stephen J; Leu, N Adrian; Xu, Yang; Gregory, Brian D; Schultz, Richard M; Wang, P Jeremy

2018-05-25

The N6-methyladenosine (m6A) modification is the most prevalent internal RNA modification in eukaryotes. The majority of m6A sites are found in the last exon and 3' UTRs. Here we show that the nuclear m6A reader YTHDC1 is essential for embryo viability and germline development in mouse. Specifically, YTHDC1 is required for spermatogonial development in males and for oocyte growth and maturation in females; Ythdc1-deficient oocytes are blocked at the primary follicle stage. Strikingly, loss of YTHDC1 leads to extensive alternative polyadenylation in oocytes, altering 3' UTR length. Furthermore, YTHDC1 deficiency causes massive alternative splicing defects in oocytes. The majority of splicing defects in mutant oocytes are rescued by introducing wild-type, but not m6A-binding-deficient, YTHDC1. YTHDC1 is associated with the pre-mRNA 3' end processing factors CPSF6, SRSF3, and SRSF7. Thus, YTHDC1 plays a critical role in processing of pre-mRNA transcripts in the oocyte nucleus and may have similar non-redundant roles throughout fetal development.

Cryopreservation of in vitro matured oocytes in addition to ovarian tissue freezing for fertility preservation in paediatric female cancer patients before and after cancer therapy.

PubMed

Abir, R; Ben-Aharon, I; Garor, R; Yaniv, I; Ash, S; Stemmer, S M; Ben-Haroush, A; Freud, E; Kravarusic, D; Sapir, O; Fisch, B

2016-04-01

Is a protocol that combines in vitro maturation of germinal vesicle-stage oocytes and their vitrification with freezing of cortical ovarian tissue feasible for use in fertility preservation for both chemotherapy-naive paediatric patients as well as patients after initiation of cancer therapy? Follicle-containing ovarian tissue as well as oocytes that can undergo maturation in vitro can be obtained from paediatric patients (including prepubertal girls) both before and after cancer therapy. Anticancer therapy reduces the number of follicles/oocytes but this effect is less severe in young patients, particularly the paediatric age group. Autotransplantation of ovarian tissue has yielded to date 60 live births, including one from tissue that was cryostored in adolescence. However, it is assumed that autografting cryopreserved-thawed ovarian cortical tissue poses a risk of reseeding the malignancy. Immature oocytes can be collected from very young girls without hormonal stimulation and then matured in vitro and vitrified. We have previously shown that there is no difference in the number of ovarian cortical follicles between paediatric patients before and after chemotherapy. A prospective study was conducted in a cohort of 42 paediatric females with cancer (before and after therapy initiation) who underwent fertility preservation procedures in 2007-2014 at a single tertiary medical centre. The study group included girls and adolescent females with cancer: 22 before and 20 after chemotherapy. Following partial or complete oophorectomy, immature oocytes were either aspirated manually ex vivo from visible small antral follicles or filtered from spent media. Oocytes were incubated in oocyte maturation medium, and those that matured at 24 or 48 h were vitrified. Ovarian cortical tissue was cut and prepared for slow-gradual cryopreservation. Anti-Mullerian hormone (AMH) levels were measured in serum before and after oophorectomy. Ovarian tissue was successfully collected from 78.7% of the 42 patients. Oocytes were obtained from 20 patients before chemotherapy and 13 after chemotherapy. The youngest patients from whom oocytes were retrieved were aged 2 years (two atretic follicles) and 3 years. Of the 395 oocytes collected, ∼30% were atretic (29.6% in the pre-chemotherapy group, 37% in the post-chemotherapy group). One hundred twenty-one oocytes (31%) were matured in vitro and vitrified: 67.8% from patients before chemotherapy, the rest after chemotherapy. Mature oocytes suitable for vitrification were obtained from 16/20 patients before chemotherapy and from 12/13 patients after chemotherapy (maturation rate, 32 and 26.4%, respectively). There were significant correlations of the number of vitrified oocytes with patient age (more matured oocytes with older age) (P = 0.001) and with pre-oophorectomy AMH levels (P = 0.038 pre-chemotherapy group, P = 0.029 post-chemotherapy group). Oocytes suitable for vitrification were obtained both by manual aspiration of antral follicles (45%) and from rinse solutions after dissection. There were significantly more matured oocytes in the pre-chemotherapy group from aspiration than in the post-chemotherapy group after both aspiration (P < 0.033) and retrieval from rinsing fluids (P < 0.044). The number of pre-antral follicles per histological section did not differ in the pre- versus post-chemotherapy. AMH levels dropped by approximately 50% after ovarian removal in both groups, with a significant correlation between pre- and post-oophorectomy levels (P = 0.002 pre-chemotherapy group, P = 0.001 post-chemotherapy group). There were no patients between 5 years and 10 years old in the post-chemotherapy group, which might have affected some results and correlations. Oocytes from patients soon after chemotherapy might be damaged, and caution is advised when using them for fertility-restoration purposes. The viability, development capability and fertilization potential of oocytes from paediatric patients, especially prepubertal and after chemotherapy, are unknown, in particular oocytes recovered from the media after the tissue dissection step. Although more oocytes were collected and matured from chemotherapy-naïve paediatric patients, ovarian tissue and immature oocytes were also retrieved from young girls in whom cancer therapy has already been initiated. Our centre has established a protocol for potential maximal fertility preservation in paediatric female patients with cancer. Vitrified-in vitro-matured oocytes may serve as an important gamete source in paediatric female patients with cancer because the risk of reseeding the disease is avoided. Further studies are needed on the fertility-restoring potential of oocytes from paediatric and prepubertal patients, especially after exposure to chemotherapy. The study was conducted as part of the routine procedures for fertility preservation at our IVF unit. No funding outside of the IVF laboratory was received. Funding for the AMH measurements was obtained by a research grant from the Israel Science Foundation (to B.-A.I., ISF 13-1873). None of the authors have competing interests. N/A. © The Author 2016. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Detection of biotin in individual sea urchin oocytes using a bioluminescence binding assay.

PubMed

Feltus, A; Grosvenor, A L; Conover, R C; Anderson, K W; Daunert, S

2001-04-01

The ability to detect biomolecules in single cells is important in order to fully understand the processes by which many biochemical events occur. To that end, we have developed a bioluminescence binding assay capable of measuring the intracellular biotin content of individual cells. The assay depends on competition between an aequorin-biotin conjugate (AEQ-biotin) and free biotin within the oocytes for binding sites on the protein avidin. The assay is performed by microinjecting each component into the oocytes and following the resulting bioluminescence within the oocyte upon triggering of aequorin. Results obtained using sea urchin oocytes show that the assay performed within the cells behaves in a manner consistent with assay theory. Using the assay, the individual biotin content of the oocytes is an average of approximately 20 amol. To our knowledge, this is the first reported multicomponent binding assay to be performed inside an intact single cell.

Hydroxypropyl cellulose supplementation in vitrification solutions: a prospective study with donor oocytes.

PubMed

Gallardo, Miguel; Hebles, María; Migueles, Beatriz; Dorado, Mónica; Aguilera, Laura; González, Mercedes; Piqueras, Paloma; Lucas, Alejandro; Montero, Lorena; Sánchez-Martín, Pascual; Sánchez-Martín, Fernando; Risco, Ramón

2017-03-01

Hydroxypropyl cellulose (HPC), a polysaccharide that forms a viscous gel under low temperatures, is a promising substitute of the blood-derived macromolecules traditionally used in cryopreservation solutions. The performance of a protein-free, fully synthetic set of vitrification and warming solutions was assessed in a matched pair analysis with donor oocytes. A prospective study including 219 donor MII oocytes was carried out, comparing the laboratory outcomes of oocytes vitrified with HPC-based solutions and their fresh counterparts. The primary performance endpoint was the fertilization rate. Secondary parameters assessed were embryo quality on days 2 and 3. 70/73 (95.9%) vitrified MII oocytes exhibited morphologic survival 2 h post-warming, with 49 (70.0%) presented normal fertilization, compared to 105 of 146 (71.9%) MII fresh oocytes. Similar embryo quality was observed in both groups. A total of 18 embryos implanted, out of 38 embryos transferred (47.3%), resulting in 13 newborns.

Production of giant mouse oocyte nucleoli and assessment of their protein content.

PubMed

Fulka, Helena; Martinkova, Stanislava; Kyogoku, Hirohisa; Langerova, Alena; Fulka, Josef

2012-01-01

Compared with advanced developmental stage embryos and somatic cells, fully grown mammalian oocytes contain specific nucleolus-like structures (NPB - nucleolus precursor bodies). It is commonly accepted that they serve as a store of material(s) from which typical nucleoli are gradually formed. Whilst nucleoli from somatic cells can be collected relatively easily for further biochemical analyses, a sufficient number of oocyte nucleoli is very difficult to obtain. We have found that isolated oocytes nucleoli fuse very efficiently when contact is established between them. Thus, well visible giant nucleoli can be obtained, relatively easily handled and then used for further biochemical analyses. With the use of colloidal gold staining, we estimated that a single fully grown mouse oocyte nucleolus contains approximately 1.6 ng of protein. We do believe that this approach will accelerate further research aiming at analyzing the composition of oocyte nucleoli in more detail.

Current results with slow freezing and vitrification of the human oocyte.

PubMed

Boldt, Jeffrey

2011-09-01

The past decade has witnessed renewed interest in human oocyte cryopreservation (OCP). This article reviews the two general methods used for OCP, slow freezing and vitrification, compares the outcomes associated with each technique and discusses the factors that might influence success with OCP (such as oocyte selection or day of transfer). Based on available data, OCP offers a reliable, reproducible method for preservation of the female gamete and will find increasing application in assisted reproductive technology. Oocyte cryopreservation can provide a number of advantages to couples undergoing assisted reproduction or to women interested in fertility preservation. Two methods, slow freezing and vitrification, have been used successfully for oocyte cryopreservation. This article reviews and compares these methods, and discusses various factors that can impact upon success of oocyte cryopreservation. Copyright © 2011 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

Triplet pregnancy after intracytoplasmic sperm injection of cryopreserved oocytes: case report.

PubMed

Young, E; Kenny, A; Puigdomenech, E; Van Thillo, G; Tiverón, M; Piazza, A

1998-08-01

To report a triplet pregnancy that occurred after intracytoplasmic injection of sperm into cryopreserved oocytes. Case report. Instituto de Ginecología y Fertilidad (IFER), Buenos Aires, Argentina. A 36-year-old infertile patient with premature ovarian failure and a previous term pregnancy with fresh donated oocytes. We administered leuprolide acetate for pituitary down-regulation followed by E2 valerianate in incremental doses until an endometrial lining of >8 mm was observed by ultrasound. Thawing of frozen donated oocytes, intracytoplasmic sperm injection (ICSI), and translaparoscopic fallopian tube ET also were performed. Natural micronized progesterone was administered intravaginally (600 mg/d) before ET. Ultrasound at the 8th week of gestation revealed a triplet pregnancy with active fetal heartbeats. A triple intrauterine gestation was achieved with the use of microinjection into cryopreserved oocytes. This case illustrates the feasibility of oocyte cryopreservation for clinical use in the era of ICSI.

[Smoothing Gan Reinforcing Shen Method Adjuvantly Treated Poor Response of Diminished Ovari- an Reserve Patients in in vitro Fertilization and Embryo Transfer: a Clinical Study].

PubMed

Zhang, Zheng; Zhang, Xue-hong; He, Tian-you

2015-10-01

To study clinical efficacy of smoothing Gan reinforcing Shen (SGRS) method in treating poor response of diminished ovarian reserve (DOR) patients in in vitro fertilization and embryo, transfer (IVF-ET). Totally 84 DOR patients undergoing IVF-ET were assigned to the experimental group (SGRS Chinese herbs as adjuvant therapy) and the control group according to random digit table, 42 in each group. Patients in the control group received controlled ovarian hyperstimulation (COH) and IVF-ET. Those in the experimental group additionally received basic formula of SGRS method, one dose per day. The dose and use time of recombinant follicle-stimulating hormone (r-FSH) were recorded during ovarian stimulation process. On the injection day of human chorionic gonadotropin (HCG) and serum levels of estradiol (E2) on the oocyte retrieval day were determined using chemiluminescent method. E2 contents in the follicular fluid on the oocyte retrieval day were detected using ELISA. The total number of retrieved oocytes, the number of mature oocytes in metaphase II (M II), the number of normal fertilization [with two pronucleus (2PN)], the number of portable embryos, and the number of good quality embryos were recorded. The correlation between Chinese medical adjuvant therapy and the aforesaid indices were observed. The clinical pregnancy rate and the abortion rate were finally compared between the two groups. The total dose of r-FSH, the E2 level on HCG injection day, the serum E2 level on the oocyte retrieval day, the number of retrieved oocyte, the number of oocytes in M II the number of oocytes with 2PN, the number of portable embryos, and the number of good quality embryos were all positively correlated with Chinese medical adjuvant therapy (P < 0.05, P < 0.01). Compared with the control group, serum E2 levels on the HCG injection day and the oocyte retrieval day obviously increased, the number of retrieved oocytes, the number of oocytes in M II, and the number of portable embryos were increased more in the experimental group with statistical difference (P < 0.05, P < 0.01). There was no statistical significance in the clinical pregnancy rate or the abortion rate between the two groups (P > 0.05). SGRS Chinese herbs as adjuvant therapy could improve ovarian responsiveness of DOR patients undergoing IVF-ET, increase the number of retrieved oocytes, elevate the quality of oocytes and the number of embryos.

Neither Aurora B activity nor histone H3 phosphorylation is essential for chromosome condensation during meiotic maturation of porcine oocytes.

PubMed

Jelínková, Lucie; Kubelka, Michal

2006-05-01

Aurora kinase B (AURKB) is a chromosomal passenger protein that is essential for a number of processes during mitosis. Its activity is regulated by association with two other passenger proteins, INCENP and Survivin, and by phosphorylation on Thr 232. In this study, we examine expression and phosphorylation on Thr-232 of AURKB during meiotic maturation of pig oocytes in correlation with histone H3 phosphorylation and chromosome condensation. We show that histone H3 phosphorylation on Ser-10, but not on Ser-28, correlates with progressive chromosome condensation during oocyte maturation; Ser-10 phosphorylation starts around the time of the breakdown of the nuclear envelope, with the maximal activity in metaphase I, whereas Ser-28 phosphorylation does not significantly change in maturing oocytes. Treatment of oocytes with 50 microM butyrolactone I (BL-I), an inhibitor of cyclin-dependent kinases, or cycloheximide (10 microg/ml), inhibitor of proteosynthesis, results in a block of oocytes in the germinal vesicle stage, when nuclear membrane remains intact; however, condensed chromosome fibers or highly condensed chromosome bivalents can be seen in the nucleoplasm of BL-I- or cycloheximide-treated oocytes, respectively. In these treated oocytes, no or only very weak AURKB activity and phosphorylation of histone H3 on Ser-10 can be detected after 27 h of treatment, whereas phosphorylation on Ser-28 is not influenced. These results suggest that AURKB activity and Ser-10 phosphorylation of histone H3 are not required for chromosome condensation in pig oocytes, but might be required for further processing of chromosomes during meiosis.

In vitro oocyte maturation, fertilization and culture after ovum pick-up in an endangered gazelle (Gazella dama mhorr).

PubMed

Berlinguer, F; González, R; Succu, S; del Olmo, A; Garde, J J; Espeso, G; Gomendio, M; Ledda, S; Roldan, E R S

2008-02-01

The recovery of immature oocytes followed by in vitro maturation, fertilization and culture (IVMFC) allows the rescue of biological material of great genetic value for the establishment of genetic resource banks of endangered species. Studies exist on sperm cryopreservation of endangered Mohor gazelle (Gazella dama mhorr), but no work has been carried out yet on oocyte collection, fertilization and culture in this or related species. The purpose of this study was to develop a protocol for ovarian stimulation for the recovery of oocytes and subsequent IVMFC in the Mohor gazelle using frozen-thawed spermatozoa. Ovum pick-up was performed after ovarian stimulation with a total dose of 5.28 mg of ovine FSH. A total of 35 oocytes were recovered from 56 punctured follicles (62%) (N=6 females). Out of 29 cumulus-oocyte complexes matured in vitro, 3% were found at germinal vesicle stage, 7% at metaphase I, 21% were degenerated, and 69% advanced to metaphase II. Fertilization and cleavage rates of matured oocytes were 40 and 30%, respectively. Embryos cleaved in vitro up to the 6-8 cell stage but none progressed to the blastocyst stage, suggesting the existence of a developmental block and the need to improve culture conditions. Although more studies are needed to improve hormonal stimulation and oocyte harvesting, as well as IVMFC conditions, this study demonstrates for the first time the feasibility of in vitro fertilization with frozen-thawed semen of in vitro matured oocytes collected by ovum pick-up from FSH-stimulated endangered gazelles.

Evidence for an absence of deleterious effects of ultrasound on human oocytes.

PubMed

Mahadevan, M; Chalder, K; Wiseman, D; Leader, A; Taylor, P J

1987-10-01

Animal and human data would suggest that ultrasound causes deleterious effects to oocytes during meiosis. We directly compared the fertilization rate and embryonic development following in vitro fertilization and embryo transfer of those oocytes exposed to ultrasound and those not exposed in the same patient. In 39 unscreened patients a combination of laparoscopy and ultrasound was used for oocyte recovery. Laparoscopy was performed first on the most accessible ovary (usually the right) and at least one oocyte was obtained. Ultrasound-guided oocyte recovery was successful in the other inaccessible ovary. To assess how oocytes obtained by ultrasound or laparoscopy related to the pregnancy rate, two groups of patients were evaluated in whom the embryos transferred either had been exposed to ultrasound or had not been. The fertilization and the embryo cleavage rates were not significantly different between the ultrasound-exposed and the unexposed groups. The pregnancy rate was also not significantly different [9 of 49 (18.4%) for ultrasound exposed versus 14 of 74 (18.9%) for unexposed]. There was one early spontaneous abortion in each group. Further analysis of a group of 40 patients, in whom the oocytes were exposed to ultrasound in situ, after the endogenous luteinizing hormone (LH) surge had begun 1-27 hr earlier, revealed that 6 became pregnant (15%). This preliminary study suggests that exposure of human oocytes to ultrasonic waves, either during the different phases of meiosis or after the completion of meiosis, did not significantly influence the developmental potential of the in vitro fertilized embryos.

Phospholipase C-zeta deficiency as a cause for repetitive oocyte fertilization failure during ovarian stimulation for in vitro fertilization with ICSI: a case report.

PubMed

Chithiwala, Zahabiya H; Lee, Hoi Chang; Hill, David L; Jellerette-Nolan, Teru; Fissore, Rafael; Grow, Daniel; Dumesic, Daniel A

2015-09-01

The purpose of this study is to describe impaired oocyte fertilization from phospholipase C-zeta (PLC-ζ) deficiency in normal-appearing sperm that was successfully treated using calcium (Ca(2+)) ionophore with intracytoplasmic sperm injection (ICSI) of oocytes matured in vitro. An infertile couple undergoing in vitro fertilization (IVF) experienced failed oocyte fertilization following ICSI with normal-appearing sperm. A semen sample collected from the patient was used to assess the expression of sperm PLC- ζ protein by Western blot analysis and immunofluorescence and PLC-ζ bioactivity by an in vitro model of Ca(2+) release. A second IVF cycle was performed using Ca(2+) ionophore with ICSI to enhance Ca(2+)-induced oocyte activation of oocytes matured in vitro. Sperm PLC-ζ protein deficiency was demonstrated by Western blot analysis and immunofluorescence and confirmed by reduced PLC-ζ bioactivity using an in vitro model of Ca(2+) release. Nevertheless, with this sperm and supplementation of Ca(2+) ionophore following ICSI, fertilization of four of six oocytes matured in vitro was obtained. In addition, four embryos underwent cleavage and two of them reached the blastocyst stage. Transfer of these blastocysts into the uterus led to a single pregnancy and live birth. Deficiency of PLC-ζ in normal-appearing human sperm is associated with impaired Ca(2+)-dependent oocyte activation during ICSI. Under this condition, use of Ca(2+) ionophore following ICSI of oocytes matured in vitro improves embryo developmental competence, possibly through the activation of Ca(2+)-dependent mechanisms governing fertilization and preimplantation embryogenesis.

Consequences of metaphase II oocyte cryopreservation on mRNA content.

PubMed

Chamayou, S; Bonaventura, G; Alecci, C; Tibullo, D; Di Raimondo, F; Guglielmino, A; Barcellona, M L

2011-04-01

We studied the consequences of freezing/thawing processes on mRNA contents in MII oocytes after slow-freezing/rapid thawing (SF/RT) and vitrification/warming (V/W) protocols, and compared the results to fresh MII oocytes. We quantified the nuclear transcript mRNA responsible for the translation of proteins belonging either to trans-regulatory protein family or to functional structural proteins such as proteins involved in DNA structural organization (NAP1L1, TOP1, H1F0H1), chromosomal structure maintenance (SMC, SCC3, RAD21, SMC1A, SMC1B, STAG3, REC8), mitochondrial energetic pathways (ATP5GJ, SDHC), cell cycle regulation and processes (CLTA, MAPK6, CKS2) and staminal cell potency-development competence stage (DPPA3, OCT4, FOXJ2). Surplus MII oocytes were donated from patients in IVF cycles and divided in three groups of 15 oocytes. Group 1 was comprised of non-cryopreserved oocytes and Groups 2 and 3 underwent SF/RT and V/W procedures, respectively. There was an overall decrease of mRNA extracted from cryopreserved oocytes compared to control group. Only 39.4% of mRNA content were preserved after SF/RT while 63.3% of mRNA content were maintained after V/W. Oocyte cryopreservation is associated with molecular injury associated with the decrease of stored mRNA. However the V/W protocol is more conservative than SF/RT resulting in a level of mRNA sufficient to maintain biologic functions in the subsequent fertilized oocyte. Copyright © 2011 Elsevier Inc. All rights reserved.

Oocyte cryopreservation for fertility preservation in postpubertal female children at risk for premature ovarian failure due to accelerated follicle loss in Turner syndrome or cancer treatments.

PubMed

Oktay, K; Bedoschi, G

2014-12-01

To preliminarily study the feasibility of oocyte cryopreservation in postpubertal girls aged between 13 and 15 years who were at risk for premature ovarian failure due to the accelerated follicle loss associated with Turner syndrome or cancer treatments. Retrospective cohort and review of literature. Academic fertility preservation unit. Three girls diagnosed with Turner syndrome, 1 girl diagnosed with germ-cell tumor. and 1 girl diagnosed with lymphoblastic leukemia. Assessment of ovarian reserve, ovarian stimulation, oocyte retrieval, in vitro maturation, and mature oocyte cryopreservation. Response to ovarian stimulation, number of mature oocytes cryopreserved and complications, if any. Mean anti-müllerian hormone, baseline follical stimulating hormone, estradiol, and antral follicle counts were 1.30 ± 0.39, 6.08 ± 2.63, 41.39 ± 24.68, 8.0 ± 3.2; respectively. In Turner girls the ovarian reserve assessment indicated already diminished ovarian reserve. Ovarian stimulation and oocyte cryopreservation was successfully performed in all female children referred for fertility preservation. A range of 4-11 mature oocytes (mean 8.1 ± 3.4) was cryopreserved without any complications. All girls tolerated the procedure well. Oocyte cryopreservation is a feasible technique in selected female children at risk for premature ovarian failure. Further studies would be beneficial to test the success of oocyte cryopreservation in young girls. Copyright © 2014 North American Society for Pediatric and Adolescent Gynecology. Published by Elsevier Inc. All rights reserved.

Chromatin configurations in the ferret germinal vesicle that reflect developmental competence for in vitro maturation.

PubMed

Sun, X; Li, Z; Yi, Y; Ding, W; Chen, J; Engelhardt, J F; Leno, G H

2009-04-01

In several mammalian species, the configuration of germinal vesicle (GV) chromatin correlates with the developmental competence of oocytes. Yet, no study has been published on the configuration of GV chromatin in ferret, nor is it known whether a specific configuration predicts meiotic competence in this species, in spite of the potential importance of ferret cloning to the study of human disease and to species conservation efforts. Here, we report on an analysis of the chromatin configuration in ferret GV oocytes and on how they correlate with meiotic development. Three distinct configurations were identified based on the degree of chromatin condensation: (1) fibrillar chromatin (FC), featuring strands of intertwined chromatin occupying most of the visible GV region; (2) intermediate condensed chromatin (ICC), characterized by dense, irregular chromatin masses throughout the GV; and (3) condensed chromatin (CC), which is highly compact and centered around the nucleolus. We also found that chromatin configuration was related to the extent of association with cumulus cells in cumulus-oocyte complexes; CC-configured oocytes were most often surrounded by a compact cumulus layer and also a compact corona but FC-configured oocytes were associated with neither. In addition, increasing chromatin condensation corresponded to an increase in oocyte diameter. Finally, following in vitro culture, significantly more CC-configured oocytes underwent maturation to meiotic metaphase II than did FC- or ICC-configured oocytes. We conclude that, in ferret, chromatin condensation is related to the sequential achievement of meiotic competencies during oocyte growth and differentiation, and thus can be used as a predictor of competence.

Reconstruction of mammalian oocytes by germinal vesicle transfer: A systematic review

PubMed Central

Darbandi, Sara; Darbandi, Mahsa; Khorram Khorshid, Hamid Reza; Shirazi, Abolfazl; Sadeghi, Mohammad Reza; Agarwal, Ashok; Al-Hasani, Safaa; Naderi, Mohammad Mehdi; Ayaz, Ahmet; Akhondi, Mohammad Mehdi

2017-01-01

Nuclear transfer procedures have been recently applied for clinical and research targets as a novel assisted reproductive technique and were used for increasing the oocyte activity during its growth and maturation. In this review, we summarized the nuclear transfer technique for germinal vesicle stage oocytes to reconstruct the maturation of them. Our study covered publications between 1966 and August 2017. In result utilized germinal vesicle transfer techniques, fusion, and fertilization survival rate on five different mammalian species are discussed, regarding their potential clinical application. It seems that with a study on this method, there is real hope for effective treatments of old oocytes or oocytes containing mitochondrial problems in the near future. PMID:29387825

The ovary structure, previtellogenic and vitellogenic stages in parthenogenetic species Dactylobiotus dispar (Murray, 1907) (Tardigrada: Eutardigrada).

PubMed

Poprawa, Izabela

2005-10-01

The reproductive system of Dactylobiotus dispar consists of the ovary and the oviduct that opens into the rectum. The sack-like ovary is filled with the developing oocytes, which are assisted by the trophocytes. In D. dispar, the mixed vitellogenesis takes place. One part of the yolk material is produced inside the oocyte (autosynthesis), the second part is absorbed by micropinocytosis while the third part is synthesized in the trophocytes and is transported to the oocytes through the cytoplasmatic bridges. Moreover, rRNA, lipids and mitochondria are transfered from the trophocytes to the oocytes. The histochemical researches show that the reserve material accumulated in the oocytes contains proteins, polysaccharides and lipids.

Microfluidic Method of Pig Oocyte Quality Assessment in relation to Different Follicular Size Based on Lab-on-Chip Technology

PubMed Central

Walczak, Rafał; Antosik, Paweł; Sniadek, Patrycja; Piotrowska, Hanna; Bukowska, Dorota; Dziuban, Jan; Nowicki, Michał; Jaśkowski, Jędrzej M.; Brüssow, Klaus-Peter

2014-01-01

Since microfollicular environment and the size of the follicle are important markers influencing oocyte quality, the aim of this study is to present the spectral characterization of oocytes isolated from follicles of various sizes using lab-on-chip (LOC) technology and to demonstrate how follicle size may affect oocyte quality. Porcine oocytes (each, n = 100) recovered from follicles of different sizes, for example, from large (>5 mm), medium (3–5 mm), and small (<3 mm), were analyzed after preceding in vitro maturation (IVM). The LOC analysis was performed using a silicon-glass sandwich with two glass optical fibers positioned “face-to-face.” Oocytes collected from follicles of different size classes revealed specific and distinguishable spectral characteristics. The absorbance spectra (microspectrometric specificity) for oocytes isolated from large, medium, and small follicles differ significantly (P < 0.05) and the absorbance wavelengths were between 626 and 628 nm, between 618 and 620 nm, and less than 618 nm, respectively. The present study offers a parametric and objective method of porcine oocyte assessment. However, up to now this study has been used to evidence spectral markers associated with follicular size in pigs, only. Further investigations with functional-biological assays and comparing LOC analyses with fertilization and pregnancy success and the outcome of healthy offspring must be performed. PMID:25548771

Molecular Mechanisms Responsible for Increased Vulnerability of the Ageing Oocyte to Oxidative Damage

PubMed Central

Redgrove, Kate A.; McLaughlin, Eileen A.

2017-01-01

In their midthirties, women experience a decline in fertility, coupled to a pronounced increase in the risk of aneuploidy, miscarriage, and birth defects. Although the aetiology of such pathologies are complex, a causative relationship between the age-related decline in oocyte quality and oxidative stress (OS) is now well established. What remains less certain are the molecular mechanisms governing the increased vulnerability of the aged oocyte to oxidative damage. In this review, we explore the reduced capacity of the ageing oocyte to mitigate macromolecular damage arising from oxidative insults and highlight the dramatic consequences for oocyte quality and female fertility. Indeed, while oocytes are typically endowed with a comprehensive suite of molecular mechanisms to moderate oxidative damage and thus ensure the fidelity of the germline, there is increasing recognition that the efficacy of such protective mechanisms undergoes an age-related decline. For instance, impaired reactive oxygen species metabolism, decreased DNA repair, reduced sensitivity of the spindle assembly checkpoint, and decreased capacity for protein repair and degradation collectively render the aged oocyte acutely vulnerable to OS and limits their capacity to recover from exposure to such insults. We also highlight the inadequacies of our current armoury of assisted reproductive technologies to combat age-related female infertility, emphasising the need for further research into mechanisms underpinning the functional deterioration of the ageing oocyte. PMID:29312475

Inhibition of Bufo arenarum oocyte maturation induced by cholesterol depletion by methyl-beta-cyclodextrin. Role of low-density caveolae-like membranes.

PubMed

Buschiazzo, Jorgelina; Bonini, Ida C; Alonso, Telma S

2008-06-01

The invaginated structure of caveolae seems to provide an optimal environment for hormone binding leading to oocyte meiotic maturation. We conducted a quantitative analysis of lipids and proteins of detergent-free low-density membranes isolated from Bufo arenarum oocytes and we modulated cellular cholesterol to further understand how these domains perform their regulatory functions in the amphibian system. Light membranes derive from the plasma membrane as suggested by the enrichment in the activity of 5'nucleotidase. Lipid analysis by chromatography techniques revealed that this fraction is enriched in phosphatidylserine and cholesterol and that it evidences an important level of sphingomyelin. The finding of a single 21 kDa caveolin in light membranes indicates the presence of caveolae-like structures in B. arenarum oocytes. In support of this finding, c-Src is significantly associated to this fraction. Cholesterol content of oocytes treated with methyl-beta-cyclodextrin (MbetaCD) decreased when compared to control oocytes. Drug treatment inhibited meiotic maturation in a dose-dependent manner and affected the localization of caveolin and c-Src among membrane fractions. Repletion of cholesterol showed a recovery of the ability of MbetaCD-treated oocytes to mature, particularly at the 25 mM concentration in which reversibility was close to the control level. Results highlight the importance of caveolae-like microdomains for maturation signaling in Bufo oocytes.

Possible mechanism of polyspermy block in human oocytes observed by time-lapse cinematography.

PubMed

Mio, Yasuyuki; Iwata, Kyoko; Yumoto, Keitaro; Kai, Yoshiteru; Sargant, Haruka C; Mizoguchi, Chizuru; Ueda, Minako; Tsuchie, Yuka; Imajo, Akifumi; Iba, Yumiko; Nishikori, Kyoko

2012-09-01

To analyze the fertilization process related to polyspermy block in human oocytes using an in vitro culturing system for time-lapse cinematography. We had 122 oocytes donated for this study from couples that provided informed consent. We recorded human oocytes at 2,000 to 2,800 frames every 10 s during the fertilization process and thereafter every 2 min using a new in vitro culture system originally developed by the authors for time-lapse cinematography. We displayed 30 frames per second for analysis of the polyspermy block during fertilization. Three oocytes showed the leading and following sperm within the zona pellucida in the same microscopic field. The dynamic images obtained during the fertilization process using this new system revealed that once a leading sperm penetrated the zona pellucida and attached to the oocyte membrane, a following sperm was arrested from further penetration into the zona pellucida within 10 s. The present results strongly suggest the existence of a novel mechanism of polyspermy block that takes place at the zona pellucida immediately after fertilization. These findings are clearly different from previous mechanisms describing polyspermy block as the oocyte membrane block to sperm penetration and the zona reaction. The finding presented herein thus represents a novel discovery about the highly complicated polyspermy block mechanism occurring in human oocytes.

Intracellular Ca2+ and antioxidant values induced positive effect on fertilisation ratio and oocyte quality of granulosa cells in patients undergoing in vitro fertilisation.

PubMed

Tola, Esra Nur; Mungan, Muhittin Tamer; Uğuz, Abdülhadi Cihangir; Naziroğlu, Mustafa

2013-01-01

Oxidative stress is important for promoting oocyte maturation and ovulation within the follicle through calcium ion (Ca(2+)) influx. The relationship between antioxidant and cytosolic Ca(2+) levels and oocyte quality and fertilisation rate in the granulosa cells of patients undergoing in vitro fertilisation was investigated. Granulosa cells were collected from 33 patients. Cytosolic free Ca(2+) ([Ca(2+)]i) concentration, lipid peroxidation, reduced glutathione, glutathione peroxidase and oocyte quality were measured in the granulosa cells. The relationship between two drug protocols was also examined (gonadotrophin-releasing hormone antagonist and agonist protocols) and the same parameters investigated. The [Ca(2+)]i concentration (P<0.001), glutathione (P<0.05) and oocyte quality (P<0.001) values were significantly higher in the fertilised group than in the non-fertilised group, although glutathione peroxidase activity was significantly (P<0.05) higher in the non-fertilised group than in the fertilised group. The [Ca(2+)]i concentrations were also higher (P<0.001) in the good-quality oocyte groups than in the poor-quality oocyte group. There was no correlation between the two drug protocols and investigated parameters. In conclusion, it was observed that high glutathione and cytosolic Ca(2+) concentrations in granulosa cells of patients undergoing in vitro fertilisation tended to increase the fertilisation potential of oocytes.

Egg donation for stem cell research: ideas of surplus and deficit in Australian IVF patients' and reproductive donors' accounts.

PubMed

Waldby, Catherine; Carroll, Katherine

2012-05-01

We report on a study undertaken with an Australian in vitro fertilisation (IVF) clinic to understand IVF patients' and reproductive donors' perceptions of oocyte (egg) donation for stem cell research. Such perspectives are particularly valuable because IVF patients form a major recruitment group for oocyte donation for research, and because patients and donors have direct experience of the medical procedures involved. Similar studies of oocyte donation have been carried out elsewhere in the world, but to date very little social science research has been published that reports on donation for research, as distinct from donation for reproduction. Our respondents expressed a distinct unwillingness to donate viable oocytes for stem cell research. In our analysis we consider a number of factors that explain this unwillingness. These include the labour of oocyte production, the inscrutability of oocytes (the lack of a test to identify degrees of fertility) and the extent to which the oocytes' fertility sets the parameters for all downstream reproductive possibilities. We draw on the science studies literature on affordances to make sense of the social intractability of oocytes, and compare them with the respondents' much greater willingness to donate frozen embryos for human embryonic stem cells research. © 2011 The Authors. Sociology of Health & Illness © 2011 Foundation for the Sociology of Health & Illness/Blackwell Publishing Ltd.

RNA-Seq profiling of single bovine oocyte transcript abundance and its modulation by cytoplasmic polyadenylation.

PubMed

Reyes, Juan M; Chitwood, James L; Ross, Pablo J

2015-02-01

Molecular changes occurring during mammalian oocyte maturation are partly regulated by cytoplasmic polyadenylation (CP) and affect oocyte quality, yet the extent of CP activity during oocyte maturation remains unknown. Single bovine oocyte RNA sequencing (RNA-Seq) was performed to examine changes in transcript abundance during in vitro oocyte maturation in cattle. Polyadenylated RNA from individual germinal-vesicle and metaphase-II oocytes was amplified and processed for Illumina sequencing, producing approximately 30 million reads per replicate for each sample type. A total of 10,494 genes were found to be expressed, of which 2,455 were differentially expressed (adjusted P < 0.05 and fold change >2) between stages, with 503 and 1,952 genes respectively increasing and decreasing in abundance. Differentially expressed genes with complete 3'-untranslated-region sequence (279 increasing and 918 decreasing in polyadenylated transcript abundance) were examined for the presence, position, and distribution of motifs mediating CP, revealing enrichment (85%) and lack thereof (18%) in up- and down-regulated genes, respectively. Examination of total and polyadenylated RNA abundance by quantitative PCR validated these RNA-Seq findings. The observed increases in polyadenylated transcript abundance within the RNA-Seq data are likely due to CP, providing novel insight into targeted transcripts and resultant differential gene expression profiles that contribute to oocyte maturation. © 2015 Wiley Periodicals, Inc.

In vitro oocyte culture and somatic cell nuclear transfer used to produce a live-born cloned goat.

PubMed

Ohkoshi, Katsuhiro; Takahashi, Seiya; Koyama, Shin-Ichiro; Akagi, Satoshi; Adachi, Noritaka; Furusawa, Tadashi; Fujimoto, Jun-Ichiro; Takeda, Kumiko; Kubo, Masanori; Izaike, Yoshiaki; Tokunaga, Tomoyuki

2003-01-01

The use of an in vitro culture system was examined for production of somatic cells suitable for nuclear transfer in the goat. Goat cumulus-oocyte complexes were incubated in tissue culture medium TCM-199 supplemented with 10% fetal bovine serum (FBS) for 20 h. In vitro matured (IVM) oocytes were enucleated and used as karyoplast recipients. Donor cells obtained from the anterior pituitary of an adult male were introduced into the perivitelline space of enucleated IVM oocytes and fused by an electrical pulse. Reconstituted oocytes were cultured in chemically defined medium for 9 days. Two hundred and twenty-eight oocytes (70%) were fused with donor cells. After in vitro culture, seven somatic cell nuclear transfer (SCNT) oocytes (3%) developed to the blastocyst stage. SCNT embryos were transferred to the oviducts of recipient females (four 8-cell embryos per female) or uterine horn (two blastocysts per female). One male clone (NT1) was produced at day 153 from an SCNT blastocyst and died 16 days after birth. This study demonstrates that nuclear transferred goat oocytes produced using an in vitro culture system could develop to term and that donor anterior pituitary cells have the developmental potential to produce term offspring. In this study, it suggested that the artificial control of endocrine system in domestic animal might become possible by the genetic modification to anterior pituitary cells.

Identification and characterization of an oocyte factor required for development of porcine nuclear transfer embryos

PubMed Central

Miyamoto, Kei; Nagai, Kouhei; Kitamura, Naoya; Nishikawa, Tomoaki; Ikegami, Haruka; Binh, Nguyen T.; Tsukamoto, Satoshi; Matsumoto, Mai; Tsukiyama, Tomoyuki; Minami, Naojiro; Yamada, Masayasu; Ariga, Hiroyoshi; Miyake, Masashi; Kawarasaki, Tatsuo; Matsumoto, Kazuya; Imai, Hiroshi

2011-01-01

Nuclear reprogramming of differentiated cells can be induced by oocyte factors. Despite numerous attempts, these factors and mechanisms responsible for successful reprogramming remain elusive. Here, we identify one such factor, necessary for the development of nuclear transfer embryos, using porcine oocyte extracts in which some reprogramming events are recapitulated. After incubating somatic nuclei in oocyte extracts from the metaphase II stage, the oocyte proteins that were specifically and abundantly incorporated into the nuclei were identified by mass spectrometry. Among 25 identified proteins, we especially focused on a multifunctional protein, DJ-1. DJ-1 is present at a high concentration in oocytes from the germinal vesicle stage until embryos at the four-cell stage. Inhibition of DJ-1 function compromises the development of nuclear transfer embryos but not that of fertilized embryos. Microarray analysis of nuclear transfer embryos in which DJ-1 function is inhibited shows perturbed expression of P53 pathway components. In addition, embryonic arrest of nuclear transfer embryos injected with anti–DJ-1 antibody is rescued by P53 inhibition. We conclude that DJ-1 is an oocyte factor that is required for development of nuclear transfer embryos. This study presents a means for identifying natural reprogramming factors in mammalian oocytes and a unique insight into the mechanisms underlying reprogramming by nuclear transfer. PMID:21482765

Oocyte quality in mice is affected by a mycotoxin-contaminated diet.

PubMed

Hou, Yan-Jun; Xiong, Bo; Zheng, Wei-Jiang; Duan, Xing; Cui, Xiang-Shun; Kim, Nam-Hyung; Wang, Qiang; Xu, Yin-Xue; Sun, Shao-Chen

2014-05-01

Mycotoxins, such as deoxynivalenol (DON), zearalenone (ZEN), and aflatoxin (AF), are commonly found in many food commodities and may impair the growth and reproductive efficiency of animals and humans. We investigated the effects of a mycotoxin-contaminated diet on mouse oocyte quality. Maize contaminated with DON (3.875 mg/kg), ZEN (1,897 μg/kg), and AF (806 μg/kg) was incorporated into a mouse diet at three different levels (0, 15, and 30% w/w). After 4 weeks, ovarian and germinal vesicle oocyte indices decreased in mycotoxin-fed mice. Oocytes from these mice exhibited low developmental competence with reduced germinal vesicle breakdown and polar body extrusion rates. Embryo developmental competence also showed a similar pattern, and the majority of embryos could not develop to the morula stage. Actin expression was also reduced in both the oocyte cortex and cytoplasm, which was accompanied by decreased expression of the actin nucleation factors profilin-1 and mDia1. Moreover, a large percentage of oocytes derived from mice that were fed a mycotoxin-contaminated diet exhibited aberrant spindle morphology, a loss of the cortical granule-free domain, and abnormal mitochondrial distributions, which further supported the decreased oocyte quality. Thus, our results demonstrate that mycotoxins are toxic to the mouse reproductive system by affecting oocyte quality. Copyright © 2013 Wiley Periodicals, Inc.

Social oocyte cryopreservation: a portrayal of Brazilian women.

PubMed

Santo, Elisangela V Espirito; Dieamant, Felipe; Petersen, Claudia G; Mauri, Ana L; Vagnini, Laura D; Renzi, Adriana; Zamara, Camila; Oliveira, João Batista A; Baruffi, Ricardo L R; Franco, José G

2017-06-01

This study aimed to determine what Brazilian childless women of reproductive age think about oocyte cryopreservation to postpone pregnancy and their reasons for performing or not performing this procedure. Women of reproductive age were randomly selected from the general population using different e-mail lists and were invited to participate in the study by completing an online web survey regarding social oocyte cryopreservation. The survey was also distributed through social media to women of reproductive age. Although most of the responders had a partner (86.9%) and had already planned the pregnancy of their first child (69.6%), 85.4% (379) considered the potential of social oocyte freezing to improve their chances of giving birth later in life. Those that had already planned pregnancy were two times more likely to intend to freeze their oocytes (p=0.03). The most important barrier for not undergoing oocyte cryopreservation was cost. The women who indicated that they could not currently undergo the procedure now because of cost were two times (p=0.03) more likely to intend to cryopreserve their oocytes than women who thought that they would not need to delay pregnancy. Brazilian women who think that they are not ready to have a family are discovering the option of oocyte cryopreservation. Most participants considered safeguarding their reproductive potential. Making the procedure more accessible could give women the opportunity to make proactive decisions about the future of their fertility.

Quantitative imaging of lipids in live mouse oocytes and early embryos using CARS microscopy

PubMed Central

Bradley, Josephine; Pope, Iestyn; Masia, Francesco; Sanusi, Randa; Langbein, Wolfgang; Borri, Paola

2016-01-01

Mammalian oocytes contain lipid droplets that are a store of fatty acids, whose metabolism plays a substantial role in pre-implantation development. Fluorescent staining has previously been used to image lipid droplets in mammalian oocytes and embryos, but this method is not quantitative and often incompatible with live cell imaging and subsequent development. Here we have applied chemically specific, label-free coherent anti-Stokes Raman scattering (CARS) microscopy to mouse oocytes and pre-implantation embryos. We show that CARS imaging can quantify the size, number and spatial distribution of lipid droplets in living mouse oocytes and embryos up to the blastocyst stage. Notably, it can be used in a way that does not compromise oocyte maturation or embryo development. We have also correlated CARS with two-photon fluorescence microscopy simultaneously acquired using fluorescent lipid probes on fixed samples, and found only a partial degree of correlation, depending on the lipid probe, clearly exemplifying the limitation of lipid labelling. In addition, we show that differences in the chemical composition of lipid droplets in living oocytes matured in media supplemented with different saturated and unsaturated fatty acids can be detected using CARS hyperspectral imaging. These results demonstrate that CARS microscopy provides a novel non-invasive method of quantifying lipid content, type and spatial distribution with sub-micron resolution in living mammalian oocytes and embryos. PMID:27151947

Quantitative imaging of lipids in live mouse oocytes and early embryos using CARS microscopy.

PubMed

Bradley, Josephine; Pope, Iestyn; Masia, Francesco; Sanusi, Randa; Langbein, Wolfgang; Swann, Karl; Borri, Paola

2016-06-15

Mammalian oocytes contain lipid droplets that are a store of fatty acids, whose metabolism plays a substantial role in pre-implantation development. Fluorescent staining has previously been used to image lipid droplets in mammalian oocytes and embryos, but this method is not quantitative and often incompatible with live cell imaging and subsequent development. Here we have applied chemically specific, label-free coherent anti-Stokes Raman scattering (CARS) microscopy to mouse oocytes and pre-implantation embryos. We show that CARS imaging can quantify the size, number and spatial distribution of lipid droplets in living mouse oocytes and embryos up to the blastocyst stage. Notably, it can be used in a way that does not compromise oocyte maturation or embryo development. We have also correlated CARS with two-photon fluorescence microscopy simultaneously acquired using fluorescent lipid probes on fixed samples, and found only a partial degree of correlation, depending on the lipid probe, clearly exemplifying the limitation of lipid labelling. In addition, we show that differences in the chemical composition of lipid droplets in living oocytes matured in media supplemented with different saturated and unsaturated fatty acids can be detected using CARS hyperspectral imaging. These results demonstrate that CARS microscopy provides a novel non-invasive method of quantifying lipid content, type and spatial distribution with sub-micron resolution in living mammalian oocytes and embryos. © 2016. Published by The Company of Biologists Ltd.

Effects of polyunsaturated fatty acids and prostaglandins on oocyte maturation in a marine teleost, the European sea bass (Dicentrarchus labrax).

PubMed

Sorbera, L A; Asturiano, J F; Carrillo, M; Zanuy, S

2001-01-01

The effects of the polyunsaturated fatty acids (PUFAs), arachidonic acid (AA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and prostaglandins (PGs) on oocyte maturation were investigated in a marine teleost, the sea bass (Dicentrarchus labrax). Follicle-enclosed postvitellogenic, preovulatory oocytes were cultured in vitro and maturation was verified by assessing volume increase, lipid droplet coalescence, yolk clarification, and germinal vesicle migration and breakdown. Human chorionic gonadotropin was administered as the maturation-inducing gonadotropin (GTH) and was capable of inducing maturation in a time- and dose-dependent manner. Free AA induced maturation in a dose- and time-dependent manner and enhanced GTH-induced maturation, while EPA, DHA, and oleic acid were ineffective. Maturation induced by GTH was significantly suppressed by a phospholipase A(2) blocker, suggesting that mobilization of AA was involved in GTH-induced maturation. Moreover, EPA and DHA exhibited a significant, dose-dependent attenuation of GTH-induced maturation. Maturation induced by GTH was inhibited in the presence of a cyclooxygenase inhibitor, indomethacin, and this inhibition was reversed by addition of AA, PGE(2), or PGF(2alpha). PGE(2) and PGF(2alpha) alone were both effective stimulators of maturation, while PGE(1) and PGE(3) were ineffective. The effect of PUFAs on oocyte maturation in vitro were corroborated with studies in vivo. Oocytes were obtained from females fed a commercial, PUFA-enriched diet (RD) and maturational behavior was compared with oocytes from females fed a natural diet (ND) with a higher EPA content and n-3:n-6 ratio. Although no significant difference was observed in the rate of spontaneous oocyte maturation, a higher percentage of GTH-induced maturation and lower percentage of atresia were observed in RD oocytes. Moreover, while basal PGE production from oocytes from both groups was the same, RD oocytes produced significantly higher levels of PGE in the presence of hCG. The results from this study provide evidence for the participation of AA metabolism in GTH-induced oocyte maturation, and suggest that other PUFAs and PGs may play important roles in the induction of maturation in a marine teleost.

Positive effects of Forskolin (stimulator of lipolysis) treatment on cryosurvival of in vitro matured porcine oocytes.

PubMed

Fu, Xiang-Wei; Wu, Guo-Quan; Li, Jun-Jie; Hou, Yun-Peng; Zhou, Guang-Bin; Lun-Suo; Wang, Yan-Ping; Zhu, Shi-En

2011-01-15

In order to examine its effect on oocyte lipid content and cryosurvival, Forskolin was added to the medium for in vitro maturation of porcine oocytes. Treatments were control (IVM without Forskolin during the 42 h incubation period), addition of 10 μM Forskolin for the entire 42 h (0-42) and addition of 10 μM Forskolin between 24 and 42 h only (24-42). In Experiment 1, treatments did not differ significantly in cleavage rate, but the blastocyst formation rate was lower in the 0-42 group than for control and 24-42 group oocytes (17, 32 and 40%, respectively; P < 0.05). It was shown in Experiment 2 that Forskolin treatment from 0-42 h and from 24-42 h significantly reduced lipid content of oocytes compared to that of control cells (65 and 99 vs. 140 μm(2) intensity of fluorescence, respectively; P < 0.05). In Experiment 3, the percentage of oocyte survival after cryopreservation and thawing was significantly higher in both Forskolin treatment groups than in control oocytes (72% for 0-42, 65% for 24-42 and 52% for control; P < 0.05). However, Forskolin treatment did not increase cleavage rates of vitrified in vitro matured porcine oocytes (Control group 28%, 0-42 h group 0%, 24-42 h group 26.67%). Addition of Forskolin affected the nuclear maturation of porcine oocytes. The percentage of PBE (polar body extrusion) were significantly reduced in the 0-42 h group (0-42 h group 42.00 ± 2.08 vs. Control group 79.70 ± 2.82 and 24-42 h group 70.60 ± 2.83; P < 0.05). The 24-42 h group showed similar nuclear status to that of the Control group. We propose that delipation engendered by incubation with 10 μM Forskolin during 24-42 hours of maturation increased cryosurvival of in vitro-maturated porcine oocytes and that attendant chemical lipolysis did not impair their further development as it may have done in oocytes incubated with Forskolin for the full 42 h. Copyright © 2011 Elsevier Inc. All rights reserved.

In vitro culture of oocytes and granulosa cells collected from normal, obese, emaciated and metabolically stressed ewes.

PubMed

Tripathi, S K; Farman, M; Nandi, S; Mondal, S; Gupta, Psp; Kumar, V Girish

2016-07-01

The present study was undertaken to investigate the oocyte morphology, its fertilizing capacity and granulosa cell functions in ewes (obese, normal, metabolic stressed and emaciated). Ewes (Ovis aries) of approximately 3 years of age (Bellary breed) from a local village were screened, chosen and categorized into a) normal b) obese but not metabolically stressed, c) Emaciated but not metabolically stressed d) Metabolically stressed based on body condition scoring and blood markers. Oocytes and granulosa cells were collected from ovaries of the ewes of all categories after slaughter and were classified into good (oocytes with more than three layers of cumulus cells and homogenous ooplasm), fair (oocytes one or two layers of cumulus cells and homogenous ooplasm) and poor (denuded oocytes or with dark ooplasm). The good and fair quality oocytes were in vitro matured and cultured with fresh semen present and the fertilization, cleavage and blastocyst development were observed. The granulosa cells were cultured for evaluation of metabolic activity by use of the MTT assay, and cell viability, cell number as well as estrogen and progesterone production were assessed. It was observed that the good and fair quality oocytes had greater metabolic activity when collected from normal and obese ewes compared with those from emaciated and metabolically stressed ewes. No significant difference was observed in oocyte quality and maturation amongst the oocytes collected from normal and obese ewes. The cleavage and blastocyst production rates were different for the various body condition classifications and when ranked were: normal>obese>metabolically stressed>emaciated. Lesser metabolic activity was observed in granulosa cells obtained from ovaries of emaciated ewes. However, no changes were observed in viability and cell number of granulosa cells obtained from ewes with the different body condition categories. Estrogen and progesterone production from cultured granulosa cells were not different in normal and obese ewes. Estrogen and progesterone secretions were less from granulosa cells recovered from metabolically stressed and emaciated ewes. The results suggested that oocyte morphology, fertilizing capacity and granulosa cell growth were dependent on body condition and feeding status of the animals. Copyright © 2016. Published by Elsevier B.V.

Use of Both Cumulus Cells’ Transcriptomic Markers and Zona Pellucida Birefringence to Select Developmentally Competent Oocytes in Human Assisted Reproductive Technologies

PubMed Central

2015-01-01

Background Selection of the best oocyte for subsequent steps of fertilization and embryo transfer was shown to be the crucial step in human infertility treatment procedure. Oocyte selection using morphological criteria mainly Zona pellucida (ZP) has been the gold standard method in assisted reproductive technologies (ART) clinics, but this selection approach has limitations in terms of accuracy, objectivity and constancy. Recent studies using OMICs-based approaches have allowed the identification of key molecular markers that quantitatively and non-invasively predict the oocyte quality for higher pregnancy rates and efficient infertility treatment. These biomarkers are a valuable reinforcement of the morphological selection criteria widely used in in vitro fertilization (IVF) clinics. In this context, this study was designed to investigate the relationship between transcriptomic predictors of oocyte quality found by our group and the conventional morphological parameters of oocyte quality mainly the ZP birefringence. Results Microarray data revealed that 48 and 27 differentially expressed candidate genes in cumulus cells (CCs) were respectively overexpressed and underexpressed in the ZGP (Zona Good Pregnant) versus ZBNP (Zona Bad Non Pregnant) groups. More than 70% of previously reported transcriptomic biomarkers of oocyte developmental competence were confirmed in this study. The analysis of possible association between ZP birefringence versus molecular markers approach showed an absence of correlation between them using the current set of markers. Conclusions This study suggested a new integrative approach that matches morphological and molecular approaches used to select developmentally competent oocytes able to lead to successful pregnancy and the delivery of healthy baby. For each ZP birefringence score, oocytes displayed a particular CCs' gene expression pattern. However, no correlations were found between the 7 gene biomarkers of oocyte developmental potential and the ZP birefringence score. Further studies using larger lists of candidate markers are required to identify suitable genes that are highly correlated with the morphological criteria, and therefore able to reinforce the accuracy of oocyte selection and the effectiveness of infertility treatment. PMID:25923296

Oocyte-specific deletion of N-WASP does not affect oocyte polarity, but causes failure of meiosis II completion.

PubMed

Wang, Zhen-Bo; Ma, Xue-Shan; Hu, Meng-Wen; Jiang, Zong-Zhe; Meng, Tie-Gang; Dong, Ming-Zhe; Fan, Li-Hua; Ouyang, Ying-Chun; Snapper, Scott B; Schatten, Heide; Sun, Qing-Yuan

2016-09-01

There is an unexplored physiological role of N-WASP (neural Wiskott-Aldrich syndrome protein) in oocyte maturation that prevents completion of second meiosis. In mice, N-WASP deletion did not affect oocyte polarity and asymmetric meiotic division in first meiosis, but did impair midbody formation and second meiosis completion. N-WASP regulates actin dynamics and participates in various cell activities through the RHO-GTPase-Arp2/3 (actin-related protein 2/3 complex) pathway, and specifically the Cdc42 (cell division cycle 42)-N-WASP-Arp2/3 pathway. Differences in the functions of Cdc42 have been obtained from in vitro compared to in vivo studies. By conditional knockout of N-WASP in mouse oocytes, we analyzed its in vivo functions by employing a variety of different methods including oocyte culture, immunofluorescent staining and live oocyte imaging. Each experiment was repeated at least three times, and data were analyzed by paired-samples t-test. Oocyte-specific deletion of N-WASP did not affect the process of oocyte maturation including spindle formation, spindle migration, polarity establishment and maintenance, and homologous chromosome or sister chromatid segregation, but caused failure of cytokinesis completion during second meiosis (P < 0.001 compared to control). Further analysis showed that a defective midbody may be responsible for the failure of cytokinesis completion. The present study did not include a detailed analysis of the mechanisms underlying the results, which will require more extensive further investigations. N-WASP may play an important role in mediating and co-ordinating the activity of the spindle (midbody) and actin (contractile ring constriction) when cell division occurs. The findings are important for understanding the regulation of oocyte meiosis completion and failures in this process that affect oocyte quality. None. This work was supported by the National Basic Research Program of China (No. 2012CB944404) and the National Natural Science Foundation of China (Nos 30930065, 31371451, 31272260 and 31530049). There are no potential conflicts of interests. © The Author 2016. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Nucleolus-like bodies of fully-grown mouse oocytes contain key nucleolar proteins but are impoverished for rRNA.

PubMed

Shishova, Kseniya V; Lavrentyeva, Elena A; Dobrucki, Jurek W; Zatsepina, Olga V

2015-01-15

It is well known that fully-grown mammalian oocytes, rather than typical nucleoli, contain prominent but structurally homogenous bodies called "nucleolus-like bodies" (NLBs). NLBs accumulate a vast amount of material, but their biochemical composition and functions remain uncertain. To clarify the composition of the NLB material in mouse GV oocytes, we devised an assay to detect internal oocyte proteins with fluorescein-5-isothiocyanate (FITC) and applied the fluorescent RNA-binding dye acridine orange to examine whether NLBs contain RNA. Our results unequivocally show that, similarly to typical nucleoli, proteins and RNA are major constituents of transcriptionally active (or non-surrounded) NLBs as well as of transcriptionally silent (or surrounded) NLBs. We also show, by exposing fixed oocytes to a mild proteinase K treatment, that the NLB mass in oocytes of both types contains nucleolar proteins that are involved in all major steps of ribosome biogenesis, including rDNA transcription (UBF), early rRNA processing (fibrillarin), and late rRNA processing (NPM1/nucleophosmin/B23, nucleolin/C23), but none of the nuclear proteins tested, including SC35, NOBOX, topoisomerase II beta, HP1α, and H3. The ribosomal RPL26 protein was detected within the NLBs of NSN-type oocytes but is virtually absent from NLBs of SN-type oocytes. Taking into account that the major class of nucleolar RNA is ribosomal RNA (rRNA), we applied fluorescence in situ hybridization with oligonucleotide probes targeting 18S and 28S rRNAs. The results show that, in contrast to active nucleoli, NLBs of fully-grown oocytes are impoverished for the rRNAs, which is consistent with the absence of transcribed ribosomal genes in the NLB mass. Overall, the results of this study suggest that NLBs of fully-grown mammalian oocytes serve for storing major nucleolar proteins but not rRNA. Copyright © 2014 Elsevier Inc. All rights reserved.

Ovum pick-up interval in buffalo (Bubalus bubalis) managed under wetland conditions in Argentina: Effect on follicular population, oocyte recovery, and in vitro embryo development.

PubMed

Konrad, J; Clérico, G; Garrido, M J; Taminelli, G; Yuponi, M; Yuponi, R; Crudeli, G; Sansinena, M

2017-08-01

The excellent adaptation of water buffalo (Bubalis bubalis) to swampy environments means that animals are frequently managed in areas with restricted access for reproductive procedures. The objective of this study was to evaluate the effect of the ovum pick-up (OPU) interval on follicular population, oocyte recovery, oocyte quality and in vitro embryo production. Twelve Murrah buffaloes were subjected to two consecutive dominant follicle reductions, and randomly assigned to either 7-day (n=6) or 14-day (n=6) OPU interval groups. Although there was no significant difference in the average number of small (<3mm) and large (>8mm) diameter follicles available per OPU, a higher proportion of medium-sized follicles (3-8mm) were observed in the 14-day interval group (5.129 vs 3.267; p<0.05). The number of recovered oocytes per donor was also significantly higher (4.51 vs. 2.8; p<0.05) in the 14-day interval group, although this was attributed to an increase in the proportion of lower quality oocytes (grades III and IV). After in vitro fertilization, embryo developmental competence from grade I and II oocytes was superior to that from grade III and IV oocytes, irrespective of OPU interval group. There was no significant difference in the proportion of grade I and II oocytes cleaved after sperm co-incubation; however, there was a higher proportion of blastocysts produced in 14-day interval group (28 vs. 6%, p<0.05). No blastocysts were produced from grade III and IV oocytes. This study indicates it is possible to use a 14-day interval for oocyte collection in water buffalo; this approach could be considered as an alternative when access to animals is restricted. Copyright © 2017 Elsevier B.V. All rights reserved.

Cyclic AMP Affects Oocyte Maturation and Embryo Development in Prepubertal and Adult Cattle

PubMed Central

Bernal-Ulloa, Sandra Milena; Heinzmann, Julia; Herrmann, Doris; Hadeler, Klaus-Gerd; Aldag, Patrick; Winkler, Sylke; Pache, Dorit; Baulain, Ulrich; Lucas-Hahn, Andrea; Niemann, Heiner

2016-01-01

High cAMP levels during in vitro maturation (IVM) have been related to improved blastocyst yields. Here, we employed the cAMP/cGMP modulators, forskolin, IBMX, and cilostamide, during IVM to unravel the role of high cAMP in early embryonic development produced from prepubertal and adult bovine oocytes. Oocytes were collected via transvaginal aspiration and randomly assigned to three experimental groups: TCM24 (24h IVM/control), cAMP30 (2h pre-IVM (forskolin-IBMX), 30h IVM-cilostamide), and DMSO30 (Dimethyl Sulfoxide/vehicle control). After IVM, oocytes were fertilized in vitro and zygotes were cultured in vitro to blastocysts. Meiotic progression, cAMP levels, mRNA abundance of selected genes and DNA methylation were evaluated in oocytes. Blastocysts were used for gene expression or DNA methylation analyses. Blastocysts from the cAMP30 groups were transferred to recipients. The cAMP elevation delayed meiotic progression, but developmental rates were not increased. In immature oocytes, mRNA abundance of PRKACA was higher for cAMP30 protocol and no differences were found for PDE3A, SMAD2, ZAR1, PRDX1 and SLC2A8. EGR1 gene was up-regulated in prepubertal cAMP30 immature oocytes and down-regulated in blastocysts from all in vitro treatments. A similar gene expression profile was observed for DNMT3b, BCL2L1, PRDX1 and SLC2A8 in blastocysts. Satellite DNA methylation profiles were different between prepubertal and adult oocytes and blastocysts derived from the TCM24 and DMSO30 groups. Blastocysts obtained from prepubertal and adult oocytes in the cAMP30 treatment displayed normal methylation profiles and produced offspring. These data indicate that cAMP regulates IVM in prepubertal and adult oocytes in a similar manner, with impact on the establishment of epigenetic marks and acquisition of full developmental competency. PMID:26926596

Royal jelly may improve the metabolism of glucose and redox state of ovine oocytes matured in vitro and embryonic development following in vitro fertilization.

PubMed

Eshtiyaghi, Mahbobeh; Deldar, Hamid; Pirsaraei, Zarbakht Ansari; Shohreh, Bahram

2016-12-01

The aim of this study was to investigate the effect of different concentrations of royal jelly (RJ) on in vitro maturation (IVM), fertilization, cleavage, blastocyst rates, glutathione (GSH) content in ovine oocyte, mRNA abundance of antioxidant enzymes in both oocyte and cumulus, and glucose metabolism-related genes in cumulus cells. In vitro maturation of oocyte was performed in the presence of control (RJ 0 ), 2.5 (RJ 2.5 ), 5 (RJ 5 ), and 10 (RJ 10 ) mg/mL of RJ. Nuclear status, intracellular GSH content in oocytes, and mRNA abundance of selected genes were evaluated following 24 hours of IVM. Following the IVM, fertilization and embryo culture were carried out in all the groups and embryonic development was examined. The addition of 10-mg/mL RJ to maturation media not only yielded a higher number of oocytes at MII stage but also showed an increased level of intracellular GSH content than did RJ 2.5 and control groups. Fertilization, cleavage, and blastocyst rate were higher in the RJ 10 treatment group in comparison to the control one. In cumulus cells, the expression of PFKM, PFKL, and G6PDH were increased following the addition of RJ to the maturation media. Supplementation of 10-mg/mL RJ to IVM medium increased the GPx mRNA abundance in both oocyte and cumulus cells and SOD expression in the cumulus cells. The CAT mRNA abundance was not influenced by the addition of RJ to the maturation media in either oocyte or cumulus cells. It seems that the improvement of oocyte maturation and its subsequent development in RJ 10 group may be associated with amelioration of redox status in the oocytes and activation of glucose metabolic pathways in their surrounding cumulus cells. Copyright © 2016 Elsevier Inc. All rights reserved.

Developmental competence of embryos derived from reciprocal in vitro fertilization between Yak (Bos grunniens) and cattle (Bos taurus).

PubMed

Zi, Xiang-Dong; Yin, Rong-Hua; Chen, Shao-Wei; Liang, Guan-Nan; Zhang, Da-Wei; Guo, Chun-Hua

2009-10-01

The purpose of this study was to investigate fertilization ability and embryo development to the blastocyst stage after reciprocal in vitro fertilization (IVF) between yak and cattle in an attempt to clarify the problem of low conception rate after mating yak females with cattle bulls. In vitro-matured (IVM) cattle and yak oocytes were inseminated with either Holstein or yak spermatozoa, and after an 18-h of coincubation period, a proportion of the oocytes was fixed and examined for sperm penetration, polyspermy and male pronuclear formation. The remaining oocytes were cultured in vitro and evaluated for cleavage and blastocyst formation rates. The percentage of IVM oocytes penetrated by spermatozoa ranged from 78.5 to 90.5%, and the formation of one or two pronuclei and the incidence of polyspermy did not differ among the different combinations. The cleavage and blastocyst rates were not affected by the species of the sperm, but they were affected by the species of the oocytes (P<0.05), with cattle oocytes having a higher (P<0.05) cleavage and blastocyst rates (69.9 and 31.3%) than yak oocytes (62.7 and 11.5%). The blastocyst formation rate was calculated from the cleaved zygotes. The interaction between sire and oocytes species (P<0.05) influenced blastocyst formation rate, with the highest blastocyst rate occurring in cattle oocytes fertilized with yak spermatozoa (36.5%) and the lowest rate occurring in yak oocytes fertilized with yak spermatozoa (9.4%). The effect of heterosis was apparent at the blastocyst stage, but there was a large reciprocal difference in blastocyst production between crosses. It was concluded that the low conception rate that results from crossing yaks with cattle is not due to either a species-specific block of fertilization or the developmental competence of the early stage embryo.

Role of UHRF1 in de novo DNA methylation in oocytes and maintenance methylation in preimplantation embryos

PubMed Central

Toh, Hidehiro; Ohishi, Hiroaki; Sharif, Jafar; Koseki, Haruhiko; Sasaki, Hiroyuki

2017-01-01

The methylation of cytosine at CG sites in the mammalian genome is dynamically reprogrammed during gametogenesis and preimplantation development. It was previously shown that oocyte-derived DNMT1 (a maintenance methyltransferase) is essential for maintaining and propagating CG methylation at imprinting control regions in preimplantation embryos. In mammalian somatic cells, hemimethylated-CG-binding protein UHRF1 plays a critical role in maintaining CG methylation by recruiting DNMT1 to hemimethylated CG sites. However, the role of UHRF1 in oogenesis and preimplantation development is unknown. In the present study, we show that UHRF1 is mainly, but not exclusively, localized in the cytoplasm of oocytes and preimplantation embryos. However, smaller amounts of UHRF1 existed in the nucleus, consistent with the expected role in DNA methylation. We then generated oocyte-specific Uhrf1 knockout (KO) mice and found that, although oogenesis was itself unaffected, a large proportion of the embryos derived from the KO oocytes died before reaching the blastocyst stage (a maternal effect). Whole genome bisulfite sequencing revealed that blastocysts derived from KO oocytes have a greatly reduced level of CG methylation, suggesting that maternal UHRF1 is essential for maintaining CG methylation, particularly at the imprinting control regions, in preimplantation embryos. Surprisingly, UHRF1 was also found to contribute to de novo CG and non-CG methylation during oocyte growth: in Uhrf1 KO oocytes, transcriptionally-inactive regions gained less methylation, while actively transcribed regions, including the imprinting control regions, were unaffected or only slightly affected. We also found that de novo methylation was defective during the late stage of oocyte growth. To the best of our knowledge, this is the first study to demonstrate the role of UHRF1 in de novo DNA methylation in vivo. Our study reveals multiple functions of UHRF1 during the global epigenetic reprogramming of oocytes and early embryos. PMID:28976982

Raman-microscopy investigation of vitrification-induced structural damages in mature bovine oocytes

PubMed Central

De Canditiis, Carolina; Zito, Gianluigi; Rubessa, Marcello; Roca, Maria Serena; Carotenuto, Rosa; Sasso, Antonio; Gasparrini, Bianca

2017-01-01

Although oocyte cryopreservation has great potentials in the field of reproductive technologies, it still is an open challenge in the majority of domestic animals and little is known on the biochemical transformation induced by this process in the different cellular compartments. Raman micro-spectroscopy allows the non-invasive evaluation of the molecular composition of cells, based on the inelastic scattering of laser photons by vibrating molecules. The aim of this work was to assess the biochemical modifications of both the zona pellucida and cytoplasm of vitrified/warmed in vitro matured bovine oocytes at different post-warming times. By taking advantage of Principal Component Analysis, we were able to shed light on the biochemical transformation induced by the cryogenic treatment, also pointing out the specific role of cryoprotective agents (CPs). Our results suggest that vitrification induces a transformation of the protein secondary structure from the α-helices to the β-sheet form, while lipids tend to assume a more packed configuration in the zona pellucida. Both modifications result in a mechanical hardening of this cellular compartment, which could account for the reduced fertility rates of vitrified oocytes. Furthermore, biochemical modifications were observed at the cytoplasmic level in the protein secondary structure, with α-helices loss, suggesting cold protein denaturation. In addition, a decrease of lipid unsaturation was found in vitrified oocytes, suggesting oxidative damages. Interestingly, most modifications were not observed in oocytes exposed to CPs, suggesting that they do not severely affect the biochemical architecture of the oocyte. Nevertheless, in oocytes exposed to CPs decreased developmental competence and increased reactive oxygen species production were observed compared to the control. A more severe reduction of cleavage and blastocyst rates after in vitro fertilization was obtained from vitrified oocytes. Our experimental outcomes also suggest a certain degree of reversibility of the induced transformations, which renders vitrified oocytes more similar to untreated cells after 2 h warming. PMID:28531193

Nutritional impact on gene expression and competence of oocytes used to support embryo development and livebirth by cloning procedures in goats.

PubMed

Fernandes, C C L; Aguiar, L H; Calderón, C E M; Silva, A M; Alves, J P M; Rossetto, R; Bertolini, L R; Bertolini, M; Rondina, D

2018-01-01

Changes in the nutritional plan have been shown to affect oocyte quality, crucial to oocyte donors animals used in cloning. This study aimed to evaluate the impact of diets with increasing nutritional levels (maintenance diet=M; 1.3M; 1.6M; 1.9M) fed to goats for four weeks on follicular fluid composition, gene expression and oocyte competence used to cloning in goats. Donor females were superovulated for the retrieval of matured oocytes and physical measurements reported. After four weeks, groups receiving diets above maintenance increased thickness of subcutaneous adipose tissue and body weight, with higher values in 1.9M Group (P<0.05). Treatments did not affect follicular density, number of aspirated follicles, retrieved and matured oocytes. Animals from 1.3M group had lower (P<0.05) maturation rate (44.0%) and number of viable oocytes (65.3%) than M (68.8%) and 1.9M (76.0%). Follicular fluid glucose concentrations increased with nutritional levels (P=0.010), with a difference (P<0.05) between groups 1.9M (11.4±2.6mg/dL) and M (2.6±0.5mg/dL). The diet did not affect the expression of GDF9, BMP15, and BAX genes in oocytes, but BCL2 and apoptotic index were significantly higher (P<0.05) in the 1.3M and 1.6M groups than the other groups. Following the transfer of cloned embryos, one fetus was born live of a twin pregnancy in the 1.9M Group. The association between energy intake and oocyte quality suggests better nutritional use by oocytes when the maximum flow was used (1.9M), but the optimal feeding level in cloning still needs refinement. Copyright © 2017 Elsevier B.V. All rights reserved.

Egg banking in the United States: current status of commercially available cryopreserved oocytes.

PubMed

Quaas, Alexander M; Melamed, Alexander; Chung, Karine; Bendikson, Kristin A; Paulson, Richard J

2013-03-01

To estimate the current availability of donor cryopreserved oocytes and to describe the emerging phenomenon of commercial egg banks (CEBs) in the United States. Cross-sectional survey of CEBs. E-mail, telephone, and fax survey of all CEB scientific directors, conducted April 2012. None. None. Number and location of CEBs in the United States, years in existence, number of donors, number of available oocytes, level of donor anonymity, donor screening, cost of oocytes to recipients, freezing/thawing technique, pregnancy statistics. Seven CEBs were identified and surveyed (response rate: 100%). The CEBs used three distinct operational models, had been in existence for a median of 2 years (range: 1 to 8 years), with a median 21.5 (range: 6 to 100) donors and 120 (range: 20 to 1,000) currently available oocytes. The median recommended minimum number of eggs to obtain was six (range: four to seven), at an estimated mean cost per oocyte of $2,225 (range: $1,500 to $2,500). An estimated 3,130 oocytes from 294 donors are currently stored for future use. Of these CEBs, 6 (86%) of 7 use vitrification as cryopreservation method. To date, 8,780 frozen donor oocytes from CEBs have been used for in vitro fertilization, resulting in 602 pregnancies. Pregnancy rates per oocyte, available for 5 (71%) of 7 CEBs, were 532 (7.5%) of 7,080 for CEBs using vitrification and 70 (10%) of 700 for the single CEB using slow freezing as cryopreservation method. Frozen donor eggs are currently widely available in the United States. Three different operational models are currently used, resulting in more than 600 pregnancies from oocytes obtained at CEBs. The majority of CEBs use vitrification as cryopreservation technique. Copyright © 2013 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Cloned foal derived from in vivo matured horse oocytes aspirated by the short disposable needle system

PubMed Central

Lee, Wonyou; Song, Kilyoung; Lee, Inhyung; Shin, Hyungdo; Lee, Byeong Chun

2015-01-01

Transvaginal ultrasound-guided follicle aspiration is one method of obtaining recipient oocytes for equine somatic cell nuclear transfer (SCNT). This study was conducted: (1) to evaluate the possibility of oocyte aspiration from pre-ovulatory follicles using a short disposable needle system (14-G) by comparing the oocyte recovery rate with that of a long double lumen needle (12-G); (2) to investigate the developmental competence of recovered oocytes after SCNT and embryo transfer. The recovery rates with the short disposable needle vs. the long needle were not significantly different (47.5% and 35.0%, respectively). Twenty-six SCNT embryos were transferred to 13 mares, and one mare delivered a live offspring at Day 342. There was a perfect identity match between the cloned foal and the cell donor after analysis of microsatellite DNA, and the mitochondrial DNA of the cloned foal was identical with that of the oocyte donor. These results demonstrated that the short disposable needle system can be used to recover oocytes to use as cytoplasts for SCNT, in the production of cloned foals and for other applications in equine embryology PMID:26119166

The adenosine salvage pathway as an alternative to mitochondrial production of ATP in maturing mammalian oocytes.

PubMed

Scantland, Sara; Tessaro, Irene; Macabelli, Carolina H; Macaulay, Angus D; Cagnone, Gaël; Fournier, Éric; Luciano, Alberto M; Robert, Claude

2014-09-01

Although the oocyte is the largest cell in the body and an unavoidable phase in life, its physiology is still poorly understood, and other cell types provide little insight into its unique nature. Even basic cellular functions in the oocyte such as energy metabolism are not yet fully understood. It is known that the mitochondria of the female gamete exhibit an immature form characterized by limited energy production from glucose and oxidative phosphorylation. We show that the bovine oocyte uses alternative means to maintain ATP production during maturation, namely, the adenosine salvage pathway. Meiosis resumption is triggered by destruction of cyclic AMP by phosphodiesterases producing adenosine monophosphate that is converted into ATP by adenylate kinases and creatine kinases. Inhibition of these enzymes decreased ATP production, and addition of their substrates restored ATP production in denuded oocytes. Addition of phosphocreatine to the oocyte maturation medium influenced the phenotype of the resulting blastocysts. We propose a model in which adenylate kinases and creatine kinases act as drivers of ATP production from added AMP during oocyte maturation. © 2014 by the Society for the Study of Reproduction, Inc.

Most fertilizing mouse spermatozoa begin their acrosome reaction before contact with the zona pellucida during in vitro fertilization

PubMed Central

Jin, Mayuko; Fujiwara, Eiji; Kakiuchi, Yasutaka; Okabe, Masaru; Satouh, Yuhkoh; Baba, Shoji A.; Chiba, Kazuyoshi; Hirohashi, Noritaka

2011-01-01

To fuse with oocytes, spermatozoa of eutherian mammals must pass through extracellular coats, the cumulus cell layer, and the zona pellucida (ZP). It is generally believed that the acrosome reaction (AR) of spermatozoa, essential for zona penetration and fusion with oocytes, is triggered by sperm contact with the zona pellucida. Therefore, in most previous studies of sperm–oocyte interactions in the mouse, the cumulus has been removed before insemination to facilitate the examination of sperm–zona interactions. We used transgenic mouse spermatozoa, which enabled us to detect the onset of the acrosome reaction using fluorescence microscopy. We found that the spermatozoa that began the acrosome reaction before reaching the zona were able to penetrate the zona and fused with the oocyte's plasma membrane. In fact, most fertilizing spermatozoa underwent the acrosome reaction before reaching the zona pellucida of cumulus-enclosed oocytes, at least under the experimental conditions we used. The incidence of in vitro fertilization of cumulus-free oocytes was increased by coincubating oocytes with cumulus cells, suggesting an important role for cumulus cells and their matrix in natural fertilization. PMID:21383182

Nuclear m6A reader YTHDC1 regulates alternative polyadenylation and splicing during mouse oocyte development

PubMed Central

Leu, N. Adrian; Xu, Yang; Schultz, Richard M.

2018-01-01

The N6-methyladenosine (m6A) modification is the most prevalent internal RNA modification in eukaryotes. The majority of m6A sites are found in the last exon and 3’ UTRs. Here we show that the nuclear m6A reader YTHDC1 is essential for embryo viability and germline development in mouse. Specifically, YTHDC1 is required for spermatogonial development in males and for oocyte growth and maturation in females; Ythdc1-deficient oocytes are blocked at the primary follicle stage. Strikingly, loss of YTHDC1 leads to extensive alternative polyadenylation in oocytes, altering 3’ UTR length. Furthermore, YTHDC1 deficiency causes massive alternative splicing defects in oocytes. The majority of splicing defects in mutant oocytes are rescued by introducing wild-type, but not m6A-binding-deficient, YTHDC1. YTHDC1 is associated with the pre-mRNA 3’ end processing factors CPSF6, SRSF3, and SRSF7. Thus, YTHDC1 plays a critical role in processing of pre-mRNA transcripts in the oocyte nucleus and may have similar non-redundant roles throughout fetal development. PMID:29799838

Ovarian and oocyte cryopreservation.

PubMed

Lornage, Jacqueline; Salle, Bruno

2007-08-01

The present article is an update on progress in the two available techniques of oocyte and ovarian cryopreservation: slow cooling/rapid thawing and vitrification. A new line of research has opened in recent years: freezing the whole ovary with its vascular pedicle, so as to enable vascular grafts limiting ischemia-related follicle reserve loss. The technique of mature oocyte vitrification has advanced significantly, with improved oocyte physiology, increased safety, and higher clinical pregnancy rates. The number of studies on whole ovary freezing has grown, and there has been a large-mammal (sheep) live birth by orthotopic graft with vascular anastomosis of a cryopreserved ovary. Ovarian and oocyte cryopreservation is essential to conserving the fertility of young women. Results of mature oocyte freezing techniques have improved significantly over the past few years, but remain poorer than those with embryo freezing. Mature oocyte vitrification is progressing well, but requires safety validation in view of the high cryoprotectant concentrations used. Ovarian cortex fragment freezing is widely used in patients, with two live births after orthotopic graft, worldwide. The problem of rapid graft exhaustion has led to a focus on whole ovary cryopreservation which has resulted in one live birth in a ewe.

Expression of cardiac sarcolemmal Na sup + -Ca sup 2+ exchange activity in Xenopus laevis oocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Longoni, S.; Coady, M.J.; Ikeda, T.

1988-12-01

Injection of Xenopus laevis oocytes with rabbit heart poly(A){sup +}RNA results in expression of Na{sup +} inside (Na{sub i}{sup +})-dependent Ca{sup 2+} uptake activity. The activity was measured by first loading the oocytes with Na{sup +} using nystatin and then incubating the oocytes in K{sup +} or Na{sup +} medium containing {sup 45}Ca. The expressed Na{sup +} gradient-dependent Ca{sup 2+} uptake was five to eight times that observed with water-injected oocytes or with poly(A){sup +}RNA-injected oocytes for which the Na{sup +} load step had been omitted. Induced activity was related to the amount of RNA injected and was insensitive tomore » nifedipine. Fractionation of the poly(A){sup +}RNA on a sucrose gradient determined that the active message had a size range between 3 and 8 kb. The properties of the Na{sup +} gradient-dependent Ca{sup 2+} uptake indicated that Na{sup +}-Ca{sup 2+} exchange activity had been expressed in X. laevis oocytes. The result may be useful for cloning and identifying the molecular component responsible for Na{sup +}-Ca{sup 2+} exchange.« less

SRSF3 maintains transcriptome integrity in oocytes by regulation of alternative splicing and transposable elements.

PubMed

Do, Dang Vinh; Strauss, Bernhard; Cukuroglu, Engin; Macaulay, Iain; Wee, Keng Boon; Hu, Tim Xiaoming; Igor, Ruiz De Los Mozos; Lee, Caroline; Harrison, Andrew; Butler, Richard; Dietmann, Sabine; Jernej, Ule; Marioni, John; Smith, Christopher W J; Göke, Jonathan; Surani, M Azim

2018-01-01

The RNA-binding protein SRSF3 (also known as SRp20) has critical roles in the regulation of pre-mRNA splicing. Zygotic knockout of Srsf3 results in embryo arrest at the blastocyst stage. However, SRSF3 is also present in oocytes, suggesting that it might be critical as a maternally inherited factor. Here we identify SRSF3 as an essential regulator of alternative splicing and of transposable elements to maintain transcriptome integrity in mouse oocyte. Using 3D time-lapse confocal live imaging, we show that conditional deletion of Srsf3 in fully grown germinal vesicle oocytes substantially compromises the capacity of germinal vesicle breakdown (GVBD), and consequently entry into meiosis. By combining single cell RNA-seq, and oocyte micromanipulation with steric blocking antisense oligonucleotides and RNAse-H inducing gapmers, we found that the GVBD defect in mutant oocytes is due to both aberrant alternative splicing and derepression of B2 SINE transposable elements. Together, our study highlights how control of transcriptional identity of the maternal transcriptome by the RNA-binding protein SRSF3 is essential to the development of fertilized-competent oocytes.

Truths and myths of oocyte sensitivity to controlled rate freezing.

PubMed

Coticchio, G; Bonu, M A; Sciajno, R; Sereni, E; Bianchi, V; Borini, A

2007-07-01

The mammalian oocyte is especially sensitive to cryopreservation. Because of its size and physiology, it can easily undergo cell death or sub-lethal damage as a consequence of intracellular ice formation, increase in the concentration of solutes and other undesired effects during the conversion of extracellular water into ice. This has generated the belief that oocyte storage cannot be achieved with the necessary efficiency and safety. However, many concerns raised by oocyte freezing are the result of unproven hypotheses or observations conducted under sometimes inappropriate conditions. For instance, spindle organization can undergo damage under certain freezing conditions but not with other protocols. The controversial suggestion that cryopreservation induces cortical granule discharge and zona pellucida hardening somehow questions the routine use of sperm microinjection. Damage to mouse oocytes caused by solute concentration is well documented but, in the human, there is no solid evidence that modifications of freezing mixtures, to prevent this problem, provide an actual advantage. The hope of developing oocyte cryopreservation as a major IVF option is becoming increasingly realistic, but major efforts are still required to clarify the authentic implications of oocyte cryopreservation at the cellular level and identify freezing conditions compatible with the preservation of viability and developmental ability.

Characterization of oocyte retrieval cycles with empty zona pellucida.

PubMed

Oride, Aki; Kanasaki, Haruhiko; Hara, Tomomi; Ohta, Hiroko; Kyo, Satoru

2018-01-01

To identify the factors that characterize cycles with empty zona pellucida (EZP). Thirty-six oocyte retrieval cycles from which EZP were collected and another 36 cycles from which no EZP was collected were compared. The patients were divided into three groups: those with no EZP collected during any cycle, those with EZP collected during all cycles, and those experiencing cycles both with and without EZP. The mean number of oocytes collected per cycle was higher in the cycles with EZP than without EZP. The fertilization rate of the collected oocytes and the rate of good embryo formation were significantly lower in the cycles with EZP. No significant difference was observed between the three groups in terms of age, number of oocytes collected, or hormone levels before and after the oocyte retrieval. The fertilization and pregnancy rates were highest in the patients with no EZP being collected during any cycle, followed by those experiencing cycles both with and without EZP, and then by those with EZP collected during all cycles. The observation of lower fertilization, poor embryo formation, and a low pregnancy rate in the patients with EZP suggests the poor quality of oocytes that were collected with EZP in the same cycle.

The phosphodiesterase 3 inhibitor ORG 9935 inhibits oocyte maturation in the naturally selected dominant follicle in rhesus macaques.

PubMed

Jensen, Jeffrey T; Zelinski, Mary B; Stanley, Jessica E; Fanton, John W; Stouffer, Richard L

2008-04-01

The study was conducted to determine whether the phosphodiesterase (PDE) 3 inhibitor ORG 9935 prevents the resumption of meiosis in primate oocytes during natural menstrual cycles. Regularly cycling adult female macaques (n=8) were followed during the follicular phase and then started on a 2-day treatment regimen of human recombinant gonadotropins to control the timing of ovulation. Monkeys received no further treatment (controls) or ORG 9935. Oocytes were recovered by laparoscopic follicle aspiration 27 h after an ovulatory stimulus, cultured in vitro in the absence of inhibitor and inseminated. The primary outcome was the meiotic stage of the oocyte. In six ORG 9935 cycles, five of the recovered oocytes were germinal vesicle (GV)-intact, and one exhibited GV breakdown (GVBD). In contrast, all three oocytes that recovered during control cycles were GVBD (p<.05). None of the ORG 9935-treated oocytes underwent fertilization compared with 2/3 (67%) from controls. These results demonstrate that ORG 9935 blocks resumption of meiosis in the naturally selected dominant follicle in primates and suggest that PDE3 inhibitors have potential clinical use as contraceptives in women.

X-ray induced dominant lethal mutations in mature and immature oocytes of guinea-pigs and golden hamsters.

PubMed

Cox, B D; Lyon, M F

1975-06-01

The induction of dominant lethal mutations by doses of 100-400 rad X-rays in oocytes of the guinea-pig and golden hamster was studied using criteria of embryonic mortality. For both species higher yields were obtained from mature than from immature oocytes, in contrast to results for the mouse. Data on fertility indicated that in the golden hamster, as in the mouse, immature oocytes were more sensitive to killing by X-rays than mature oocytes but that the converse was true in the guinea-pig. The dose-response relationship for mutation to dominant lethals in pre-ovulatory oocytes of guinea-pig and golden hamsters was linear, both when based on pre- and post-implantation loss and when on post-implantation loss only. The rate per unit dose was higher for the golden hamster, and the old golden hamsters were possibly slightly more sensitive than young ones. The mutation rate data for mature oocytes of the mouse, using post-implantation loss alone, also fitted a linear dose-response relationship, except that the rate per unit dose was lower than for the other two species.

Cell Autonomous Phosphoinositide 3-Kinase Activation in Oocytes Disrupts Normal Ovarian Function Through Promoting Survival and Overgrowth of Ovarian Follicles

PubMed Central

Ebbert, Katherine; Cordeiro, Marilia H.; Romero, Megan; Zhu, Jie; Serna, Vanida Ann; Whelan, Kelly A.; Woodruff, Teresa K.

2015-01-01

In this study, we explored the effects of oocytic phosphoinositide 3-kinase (PI3K) activation on folliculogensis by generating transgenic mice, in which the oocyte-specific Cre-recombinase induces the expression of constitutively active mutant PI3K during the formation of primordial follicles. The ovaries of neonatal transgenic (Cre+) mice showed significantly reduced apoptosis in follicles, which resulted in an excess number of follicles per ovary. Thus, the elevation of phosphatidylinositol (3,4,5)-trisphosphate levels within oocytes promotes the survival of follicles during neonatal development. Despite the increase in AKT phosphorylation, primordial follicles in neonatal Cre+ mice remained dormant demonstrating a nuclear accumulation of phosphatase and tensin homolog deleted on chromosome 10 (PTEN). These primordial follicles containing a high level of nuclear PTEN persisted in postpubertal females, suggesting that PTEN is the dominant factor in the maintenance of female reproductive lifespan through the regulation of primordial follicle recruitment. Although the oocytic PI3K activity and PTEN levels were elevated, the activation of primordial follicles and the subsequent accumulation of antral follicles with developmentally competent oocytes progressed normally in prepubertal Cre+ mice. However, mature Cre+ female mice were anovulatory. Because postnatal day 50 Cre+ mice released cumulus-oocyte complexes with developmentally competent oocytes in response to super-ovulation treatment, the anovulatory phenotype was not due to follicular defects but rather endocrine abnormalities, which were likely caused by the excess number of overgrown follicles. Our current study has elucidated the critical role of oocytic PI3K activity in follicular function, as well as the presence of a PTEN-mediated mechanism in the prevention of immature follicle activation. PMID:25594701

Recent advances in understanding oogenesis: interactions with the cytoskeleton, microtubule organization, and meiotic spindle assembly in oocytes

PubMed Central

Marlow, Florence L.

2018-01-01

Maternal control of development begins with production of the oocyte during oogenesis. All of the factors necessary to complete oocyte maturation, meiosis, fertilization, and early development are produced in the transcriptionally active early oocyte. Active transcription of the maternal genome is a mechanism to ensure that the oocyte and development of the early embryo begin with all of the factors needed for successful embryonic development. To achieve the maximum maternal store, only one functional cell is produced from the meiotic divisions that produce the oocyte. The oocyte receives the bulk of the maternal cytoplasm and thus is significantly larger than its sister cells, the tiny polar bodies, which receive a copy of the maternal genome but essentially none of the maternal cytoplasm. This asymmetric division is accomplished by an enormous cell that is depleted of centrosomes in early oogenesis; thus, meiotic divisions in oocytes are distinct from those of mitotic cells. Therefore, these cells must partition the chromosomes faithfully to ensure euploidy by using mechanisms that do not rely on a conventional centrosome-based mitotic spindle. Several mechanisms that contribute to assembly and maintenance of the meiotic spindle in oocytes have been identified; however, none is fully understood. In recent years, there have been many exciting and significant advances in oogenesis, contributed by studies using a myriad of systems. Regrettably, I cannot adequately cover all of the important advances here and so I apologize to those whose beautiful work has not been included. This review focuses on a few of the most recent studies, conducted by several groups, using invertebrate and vertebrate systems, that have provided mechanistic insight into how microtubule assembly and meiotic spindle morphogenesis are controlled in the absence of centrosomes.

Effect of the expression of aquaporins 1 and 3 in mouse oocytes and morulae on the nucleation temperature for intracellular ice formation

PubMed Central

Seki, Shinsuke; Edashige, Keisuke; Wada, Sakiko; Mazur, Peter

2013-01-01

The occurrence of intracellular ice formation (IIF) is the most important factor determining whether or not cells survive a cryopreservation procedure. What is not clear is the mechanism or route by which an external ice crystal can traverse the plasma membrane and cause the heterogeneous nucleation of the supercooled solution within the cell. We have hypothesized that one route is through preexisting pores in aquaporin (AQP) proteins that span the plasma membranes of many cell types. Since the plasma membrane of mature mouse oocytes expresses little AQP, we compared the ice nucleation temperature of native oocytes with that of oocytes induced to express AQP1 and AQP3. The oocytes were suspended in 1.0 M ethylene glycol in PBS for 15 minutes, cooled in a Linkam cryostage to –7.0 °C, induced to freeze externally, and finally cooled at 20 °C/min to –70 °C. IIF that occurred during the 20 °C/min cooling is manifested by abrupt black flashing. The mean IIF temperatures for native oocytes, for oocytes sham injected with water, for oocytes expressing AQP1, and for those expressing AQP3 were –34, –40, –35, and –25 °C, respectively. The fact that the ice nucleation temperature of oocytes expressing AQP3 was 10° to 15° C higher than the others is consistent with our hypothesis. AQP3 pores can supposedly be closed by low pH or by treatment with double-stranded AQP3 RNA. However, when morulae were subjected to such treatments, the IIF temperature still remained high. A possible explanation is suggested. PMID:21734033

Physiology and Endocrinology Symposium: influence of cattle genotype (Bos indicus vs. Bos taurus) on oocyte and preimplantation embryo resistance to increased temperature.

PubMed

Paula-Lopes, F F; Lima, R S; Satrapa, R A; Barros, C M

2013-03-01

High environmental temperatures during the hot months of the year reduce reproductive performance in cattle. Summer heat stress depression in fertility is a multifactorial problem; however, there is evidence that the bovine germinal vesicle and maturing oocyte, as well as the early embryo, are major targets of the deleterious effects of heat stress. Such adverse effects are less pronounced in heat-tolerant breeds (Bos indicus) than heat-sensitive breeds (Bos taurus). This genetic variation results from the greater thermoregulatory ability and cellular thermoresistance of heat-tolerant breeds. Heat-induced oocyte cellular damage occurs in both cytoplasmic and nuclear compartments. Heat shock has been shown to reduce oocyte nuclear maturation, induce apoptosis, compromise oocyte cytoskeleton, and impair oocyte mitochondrial function and developmental competence. However, the oocyte cytoplasm is more susceptible to heat shock than the nucleus. This effect is greater for Bos taurus than Bos indicus oocytes. The detrimental effects of heat shock are also critical during the first cleavage divisions when most of the embryonic genome is inactive; however, the bovine embryo becomes more resistant to increased temperature as it proceeds through development. Several studies demonstrated that Bos indicus embryos are more thermotolerant than Bos taurus embryos. Adaptive changes involved in acquisition of thermotolerance are likely derived from changes in gene expression and (or) activity of biochemical molecules that control cellular functions against stress. Recently, molecules such as IGF-I and caspase inhibitor z-DEVD-fmk have been shown to exert a thermoprotective role, rescuing heat-induced oocyte and embryo cellular damage and developmental competence. Therefore, cattle genotype and thermoprotective molecules can be considered as an alternative to modulate the effects of increased temperature in reproductive function.

Application of auxin-inducible degron technology to mouse oocyte activation with PLCζ.

PubMed

Miura, Kento; Matoba, Shogo; Ogonuki, Narumi; Namiki, Takafumi; Ito, Junya; Kashiwazaki, Naomi; Ogura, Atsuo

2018-05-05

In mammals, spermatozoa activate oocytes by triggering a series of intracellular Ca 2+ oscillations with phospholipase C zeta (PLCζ), a sperm-borne oocyte-activating factor. Because the introduction of PLCζ alone can induce oocyte activation, it might be a promising reagent for assisted reproductive technologies. To test this possibility, we injected human PLCζ (hPLCζ) mRNA into mouse oocytes at different concentrations. We observed the oocyte activation and subsequent embryonic development. Efficient oocyte activation and embryonic development to the blastocyst stage was achieved only with a limited range of mRNA concentrations (0.1 ng/μl). Higher concentrations of mRNA caused developmental arrest of most embryos, suggesting that excessive PLCζ protein might be harmful at this stage. In a second series of experiments, we aimed to regulate the PLCζ protein concentration in oocytes by applying auxin-inducible degron (AID) technology that allows rapid degradation of the target protein tagged with AID induced by auxin. Injection of the hPLCζ protein tagged with AID and enhanced green fluorescent protein (hPLCζ-AID-EGFP) demonstrated that high EGFP expression levels at the late 1-cell stage were efficiently reduced by auxin treatment, suggesting efficient hPLCζ degradation by this system. Furthermore, the defective development observed with higher concentrations of hPLCζ-AID-EGFP mRNA was rescued following auxin treatment. Full-term offspring were obtained by round spermatid injection with optimized hPLCζ-AID activation. Our results indicate that this AID technology can be applied to regulate the protein levels in mouse oocytes and that our optimized PLCζ system could be used for assisted fertilization in mammals.

RNA- binding protein Stau2 is important for spindle integrity and meiosis progression in mouse oocytes

PubMed Central

Cao, Yan; Du, Juan; Chen, Dandan; Wang, Qian; Zhang, Nana; Liu, Xiaoyun; Liu, Xiaoyu; Weng, Jing; Liang, Yuanjing; Ma, Wei

2016-01-01

ABSTRACT Staufen2 (Stau2) is a double-stranded RNA-binding protein involved in cell fate decision by regulating mRNA transport, mRNA stability, translation, and ribonucleoprotein assembly. Little is known about Stau2 expression and function in mammalian oocytes during meiosis. Herein we report the sub-cellular distribution and function of Stau2 in mouse oocyte meiosis. Western blot analysis revealed high and stable expression of Stau2 in oocytes from germinal vesicle (GV) to metaphase II (MII). Immunofluorescence showed that Stau2 was evenly distributed in oocytes at GV stage, and assembled as filaments after germinal vesicle breakdown (GVBD), particularly, colocalized with spindle at MI and MII. Stau2 was disassembled when microtubules were disrupted with nocodazole, on the other hand, when MTs were stabilized with taxol, Stau2 was not colocalized with the stabilized microtubules, but aggregated around the chromosomes array, indicating Stau2 assembly and colocalization with microtubules require both microtubule integrity and its normal dynamics. During interphase and mitosis of BHK and MEF cells, Stau2 was not distributed on microtubules, but colocalized with cis-Golgi marker GM130, implying its association with Golgi complex but not the spindle in fully differentiated somatic cells. Specific morpholino oligo-mediated Stau2 knockdown disrupted spindle formation, chromosome alignment and microtubule-kinetochore attachment in oocytes. The majority oocytes were arrested at MI stage, with bright MAD1 at kinetochores, indicating activation of spindle assembly checkpoint (SAC). Some oocytes were stranded at telophase I (TI), implying suppressed first polar body extrution. Together these data demonstrate that Stau2 is required for spindle formation and timely meiotic progression in mouse oocytes. PMID:27433972

RNA- binding protein Stau2 is important for spindle integrity and meiosis progression in mouse oocytes.

PubMed

Cao, Yan; Du, Juan; Chen, Dandan; Wang, Qian; Zhang, Nana; Liu, Xiaoyun; Liu, Xiaoyu; Weng, Jing; Liang, Yuanjing; Ma, Wei

2016-10-01

Staufen2 (Stau2) is a double-stranded RNA-binding protein involved in cell fate decision by regulating mRNA transport, mRNA stability, translation, and ribonucleoprotein assembly. Little is known about Stau2 expression and function in mammalian oocytes during meiosis. Herein we report the sub-cellular distribution and function of Stau2 in mouse oocyte meiosis. Western blot analysis revealed high and stable expression of Stau2 in oocytes from germinal vesicle (GV) to metaphase II (MII). Immunofluorescence showed that Stau2 was evenly distributed in oocytes at GV stage, and assembled as filaments after germinal vesicle breakdown (GVBD), particularly, colocalized with spindle at MI and MII. Stau2 was disassembled when microtubules were disrupted with nocodazole, on the other hand, when MTs were stabilized with taxol, Stau2 was not colocalized with the stabilized microtubules, but aggregated around the chromosomes array, indicating Stau2 assembly and colocalization with microtubules require both microtubule integrity and its normal dynamics. During interphase and mitosis of BHK and MEF cells, Stau2 was not distributed on microtubules, but colocalized with cis-Golgi marker GM130, implying its association with Golgi complex but not the spindle in fully differentiated somatic cells. Specific morpholino oligo-mediated Stau2 knockdown disrupted spindle formation, chromosome alignment and microtubule-kinetochore attachment in oocytes. The majority oocytes were arrested at MI stage, with bright MAD1 at kinetochores, indicating activation of spindle assembly checkpoint (SAC). Some oocytes were stranded at telophase I (TI), implying suppressed first polar body extrution. Together these data demonstrate that Stau2 is required for spindle formation and timely meiotic progression in mouse oocytes.

In vitro steroid-induced meiosis in Rhinella arenarum oocytes: role of pre-MPF activation.

PubMed

Arias Torres, Ana Josefina; Bühler, Marta Inés; Zelarayán, Liliana Isabel

2016-04-01

In this work we showed the relationship between seasonal periods and the response of R. arenarum follicles and oocytes to different steroids. Using in vitro germinal vesicle breakdown (GVBD) assays, we demonstrated that P4 is the main steroid capable of inducing maturation in R. arenarum oocytes and follicles. In the second part of this work we showed that androgens can activate pre-maturation promoting factors (pre-MPFs) such as P4, by cytoplasm microinjection experiments. The results indicated that the steroids assayed induced oocyte and follicle maturation in a dose- and time-dependent manner. In oocytes, P4 was the most efficient steroid as a maturation inducer (EC50 of the reproductive period, 6 nM, EC50 of the non-reproductive period ≅ 30 nM). Androgens (DHEA, dehydroepiandrosterone; T, testosterone; and AD, androstenedione) were less efficient maturation inducers than P4 (EC50 reproductive period ≅ 50, 120 and 600 nM respectively). Similar results were obtained with intact follicles in both seasonal periods. Although the response of follicles to the different androgens was variable, in no case was it above the above the response induced by P4. Independently of the season, oocytes and follicles incubated in P4, P5 and T underwent GVBD after 6-10 h while oocytes and follicles incubated in DHEA and AD matured more slowly. Furthermore, we demonstrated that microinjection of mature cytoplasm from androgen-treated oocytes is sufficient to promote GVBD in immature recipient oocytes (DHEA, 57 ± 12%; AD, 60 ± 8%; T, 56 ± 13%). Thus, androgens such as DHEA, T and AD are as competent as P4 to activate pre-MPF.

Cytoplasmic regionalization in starfish oocyte occurrence and localization of cytoplasmic determinants responsible for the formation of archenteron and primary mesenchyme in starfish ( asterias amurensis) oocytes

NASA Astrophysics Data System (ADS)

Zhang, Shicui; Wu, Xianhan; Zhou, Jing; Wang, Renxue; Wu, Shangqin

1990-09-01

Starfish oocytes with intact germinal vesicles (GVs) were cut along desired planes with glass needles or ligated using silk thread loops into two parts and allowed to mature in vitro, and inseminated. The experimental results showed that (1) only the parts with GVs or partial GV contents (PGVCs) cleaved, those without any GV materials did not; but nucleated and non-nucleated fragments cut from mature eggs were able to divide; (2) the development of animal parts of oocytes containing GVs or PGVCs was like that of animal fragments of matured oocytes with female pronuclei; most of them gave rise to permanent blastulae, and just a few formed ectodermal vesicles with a little primary mesenchyme; (3) a large part of vegetal fragments with GVs or PGVCs, and the vegetal parts of mature eggs without female pronuclei developed into small but normal embryos; (4) the fragments containing GVs or PGVCs obtained from the oocytes along a plane parallel to the animal-vegetal (A-V) axis developed as normally as the halves (with or without female pronuclei) severed from mature eggs along the same axis. Based on the data above, it was concluded that (1) the non-chromatin materials in the oocyte GVs are indispensable for successful fertilization and cleavage of starfish eggs; (2) some factor (s) located asymmetrically in the vegetal hemispheres of starfish oocytes is (are) responsible for formation of the archenteron and primary mesenchyme. It is evident from the above findings that the oocyte cytoplasm of the starfish had already regionalized before the GV break-down.

Lower blastocyst quality after conventional vs. Piezo ICSI in the horse reflects delayed sperm component remodeling and oocyte activation.

PubMed

Salgado, R M; Brom-de-Luna, J G; Resende, H L; Canesin, H S; Hinrichs, Katrin

2018-04-10

The aim of this study was to evaluate the differential effects of conventional and Piezo-driven ICSI on blastocyst development, and on sperm component remodeling and oocyte activation, in an equine model. In vitro-matured equine oocytes underwent conventional (Conv) or Piezo ICSI, the latter utilizing fluorocarbon ballast. Blastocyst development was compared between treatments to validate the model. Then, oocytes were fixed at 0, 6, or 18 h after injection, and stained for the sperm tail, acrosome, oocyte cortical granules, and chromatin. These parameters were compared between injection techniques and between sham-injected and sperm-injected oocytes among time periods. Blastocyst rates were 39 and 40%. The nucleus number was lower, and the nuclear fragmentation rate was higher, in blastocysts produced by Conv. Cortical granule loss started at 0H after both sperm and sham injection. The acrosome was present at 0H in both ICSI treatments, and persisted to 18H in significantly more Conv than Piezo oocytes (72 vs. 21%). Sperm head area was unchanged at 6H in Conv but significantly increased at this time in Piezo; correspondingly, at 6H significantly more Conv than Piezo oocytes remained at MII (80 vs. 9.5%). Sham injection did not induce significant meiotic resumption. These data show that Piezo ICSI is associated with more rapid sperm component remodeling and oocyte meiotic resumption after sperm injection than is conventional ICSI, and with higher embryo quality at the blastocyst stage. This suggests that there is value in exploring the Piezo technique, utilized with a non-toxic fluorocarbon ballast, for use in clinical human ICSI.

Bathymetric and interspecific variability in maternal reproductive investment and diet of eurybathic echinoderms

NASA Astrophysics Data System (ADS)

Ross, David A. N.; Hamel, Jean-François; Mercier, Annie

2013-10-01

While conditions in shallow-water and deep-sea environments differ markedly, it remains unclear how eurybathic species adapt their life histories to cope with these changes. The present study compared indicators of maternal reproductive investment of three common echinoderms collected shallower than 20 m and deeper than 850 m: Cucumaria frondosa (Holothuroidea), Solaster endeca and Henricia sanguinolenta (Asteroidea). Depth-specific and species-specific differences were found in gonad indices (GI), potential fecundity, oocyte size frequency, as well as lipid classes and fatty acids measured in gonad tissue and oocytes. The asteroids, S. endeca and H. sanguinolenta, exemplified the interspecific trade-off between size and number of oocytes: the former had fewer larger oocytes than the latter, with higher total lipid proportions in them. However, intraspecifically, larger oocytes found in deep specimens of S. endeca did not translate into lower fecundity but rather into a seemingly higher GI, indicating greater investment per oocyte without reducing fecundity. Oocytes were absent in specimens of C. frondosa sampled in deep water, suggesting delayed or impaired maturation at the limit of their depth tolerance. Analysis of S. endeca sterol proportions in gonads and oocytes across depths showed higher sterol input into oocytes in females from the deep. Gonads of S. endeca and H. sanguinolenta contained similar essential fatty acids, but showed significant differences in major fatty acids and some of the less dominant ones, indicating diet specificities. Analyses within S. endeca showed evidence of similar feeding mode (carnivory) at both depths, but suggested shifts in the diet or synthesis of fatty acids, presumably reflecting differences in available food sources and/or adaptations to their respective environments.

Comparison of ethylene glycol and propylene glycol for the vitrification of immature porcine oocytes.

PubMed

Somfai, Tamás; Nakai, Michiko; Tanihara, Fuminori; Noguchi, Junko; Kaneko, Hiroyuki; Kashiwazaki, Naomi; Egerszegi, István; Nagai, Takashi; Kikuchi, Kazuhiro

2013-01-01

Our aim was to optimize a cryoprotectant treatment for vitrification of immature porcine cumulus-oocyte complexes (COCs). Immature COCs were vitrified either in 35% ethylene glycol (EG), 35% propylene glycol (PG) or a combination of 17.5% EG and 17.5% PG. After warming, the COCs were in vitro matured (IVM), and surviving oocytes were in vitro fertilized (IVF) and cultured. The mean survival rate of vitrified oocytes in 35% PG (73.9%) was higher (P<0.05) than that in 35% EG (27.8%). Oocyte maturation rates did not differ among vitrified and non-vitrified control groups. Blastocyst formation in the vitrified EG group (10.8%) was higher (P<0.05) than that in the vitrified PG group (2.0%) but was lower than that in the control group (25.0%). Treatment of oocytes with 35% of each cryoprotectant without vitrification revealed a higher toxicity of PG on subsequent blastocyst development compared with EG. The combination of EG and PG resulted in 42.6% survival after vitrification. The maturation and fertilization rates of the surviving oocytes were similar in the vitrified, control and toxicity control (TC; treated with EG+PG combination without cooling) groups. Blastocyst development in the vitrified group was lower (P<0.05) than that in the control and TC groups, which in turn had similar development rates (10.7%, 18.1% and 23.3%, respectively). In conclusion, 35% PG enabled a higher oocyte survival rate after vitrification compared with 35% EG. However, PG was greatly toxic to oocytes. The combination of 17.5% EG and 17.5% PG yielded reasonable survival rates without toxic effects on embryo development.

Does dietary fat intake influence oocyte competence and embryo quality by inducing oxidative stress in follicular fluid?

PubMed

Kazemi, Ashraf; Ramezanzadeh, Fatemeh; Nasr-Esfahani, Mohammad Hosein; Saboor Yaraghi, Ali Akbar; Ahmadi, Mehdi

2013-12-01

Fat-rich diet may alter oocyte development and maturation and embryonic development by inducing oxidative stress (OS) in follicular environment. To investigate the relationship between fat intake and oxidative stress with oocyte competence and embryo quality. In observational study follicular fluid was collected from 236 women undergoing assisted reproduction program. Malon-di-aldehyde (MDA) levels and total antioxidant capacity (TAC) levels of follicular fluid were assessed as oxidative stress biomarkers. In assisted reproduction treatment cycle fat consumption and its component were assessed. A percentage of metaphase ΙΙ stage oocytes, fertilization rate were considered as markers of oocyte competence and non-fragmented embryo rate, mean of blastomer and good cleavage (embryos with more than 5 cells on 3 days post insemination) rate were considered as markers of embryo quality. The MDA level in follicular fluid was positively related to polyunsaturated fatty acids intake level (p=0.02) and negatively associated with good cleavage rate (p=0.045). Also good cleavage rate (p=0.005) and mean of blastomer (p=0.006) was negatively associated with polyunsaturated fatty acids intake levels. The percentage of metaphase ΙΙ stage oocyte was positively related to the TAC levels in follicular fluid (p=0.046). The relationship between the OS biomarkers in FF and the fertilization rate was not significant. These findings revealed that fat rich diet may induce the OS in oocyte environment and negatively influence embryonic development. This effect can partially be accounted by polyunsaturated fatty acids uptake while oocyte maturation is related to TAC and oocytes with low total antioxidant capacity have lower chance for fertilization and further development.

Peritoneal fluid of women with endometriosis reduces SOD1 in bovine oocytes in vitro maturation.

PubMed

Malvezzi, Helena; Da Broi, Michele Gomes; Meola, Juliana; Rosa-E-Silva, Júlio César; Ferriani, Rui Alberto; Navarro, Paula Andrea

2018-06-01

Studies have demonstrated oxidative stress in peritoneal fluid (PF) from women with endometriosis and the importance of enzymatic antioxidant machinery to avoid oocyte oxidative damage. Considering that PF constantly surrounds the ovaries and has direct contact with the oocyte at ovulation, we wonder if PF from women with endometriosis may affect antioxidant enzyme gene expression. Thus, the present study aims to evaluate the PF impact from infertile women with minimal and mild endometriosis and from fertile control women without endometriosis on SOD1, CAT, GSR gene's expression in experimental bovine oocytes matured in vitro. Samples of PF were obtained from women who underwent videolaparoscopy-7 infertile with EI/II and 7 fertile without endometriosis. Immature bovine oocytes underwent in vitro maturation in the absence of PF and in the presence of three concentrations (1, 5 and 10%) of PF from fertile and from infertile women with EI/II. After 22 to 24 h of IVM, oocytes were denuded and stored for analysis of SOD1, CAT and GSR by real-time polymerase chain reaction. Oocyte SOD1 expression was significantly lower in the 10% endometriosis group (0.67 ± 0.32) when compared with no-peritoneal fluid (1.05 ± 0.24, p < 0.008) and 10% control groups (1.06 ± 0.22, p < 0.006). These findings raise the possibility of a deleterious influence of PF from women with EI/II on the oocyte, not only after ovulation but also during the maturation process, which could contribute to worsening oocyte quality, being one of the mechanisms related to infertility in patients with endometriosis.

[Successful pregnancies after oocyte and embryo vitrification].

PubMed

Salazar, Francisco Hernández; Loza, Erik Omar Okhuysen; Lucas, Maria Teresa Huerta J; Gutiérrez, Gustavo Romero

2008-02-01

Cryopreservation of human oocytes represents a solution for ethic conflict about frozen embryo storage for patients with risk to develop ovarian hyperstimulation syndrome; also is an available technique to preserve fertility in women with cancer under treatment, in poor response patients, in case of premature ovarian failure or aging and for other medical or social conditions that require to delay pregnancies, as well as to make easier oocyte donation programs. This paper reports two cases of successful pregnancies after embryo and oocyte vitrification, as well as their results. The technique of vitrification with the cryotop method is an excellent alternative, efficient, fast and cheap for oocyte and embryo cryopreservation with high ranges of fertilization, cleavage and pregnancies with a normal evolution.

In vitro maturation of human oocytes for assisted reproduction.

PubMed

Jurema, Marcus W; Nogueira, Daniela

2006-11-01

To describe and evaluate the current practice of in vitro maturation of oocytes for assisted reproduction. Review of the available and relevant literature regarding in vitro maturation of oocytes. In vitro maturation of human oocytes retrieved from antral ovarian follicles is an emerging procedure quickly being incorporated into the realm of assisted reproductive technologies. This new technology has several potential advantages over traditional controlled ovarian hyperstimulation for IVF, such as reduction of costs by minimizing gonadotropin and GnRH analogue use, elimination of ovarian hyperstimulation syndrome, and simplicity of protocol. In vitro maturation of oocytes for assisted reproduction in human beings still is undergoing refinement but currently is providing efficacy and safety outcome comparable to that of traditional IVF in recent selected studies. Implementing in vitro maturation into an established IVF practice is feasible and requires only a few simple adjustments. Crucial to the advancement and optimization of the technology is a better understanding of how to maximize immature oocyte developmental competence and endometrial receptivity.

Bovine oocytes and early embryos express Staufen and ELAVL RNA-binding proteins.

PubMed

Calder, M D; Madan, P; Watson, A J

2008-05-01

RNA-binding proteins (RBP) influence RNA editing, localization, stability and translation and may contribute to oocyte developmental competence by regulating the stability and turnover of oogenetic mRNAs. The expression of Staufen 1 and 2 and ELAVL1, ELAVL2 RNA-binding proteins during cow early development was characterized. Cumulus-oocyte complexes were collected from slaughterhouse ovaries, matured, inseminated and subjected to embryo culture in vitro. Oocyte or preimplantation embryo pools were processed for RT-PCR and whole-mount immunofluorescence analysis of mRNA expression and protein distribution. STAU1 and STAU2 and ELAVL1 mRNAs and proteins were detected throughout cow preimplantation development from the germinal vesicle (GV) oocyte to the blastocyst stage. ELAVL2 mRNAs were detectable from the GV to the morula stage, whereas ELAVL2 protein was in all stages examined and localized to both cytoplasm and nuclei. The findings provide a foundation for investigating the role of RBPs during mammalian oocyte maturation and early embryogenesis.

Current status of human oocyte and embryo cryopreservation.

PubMed

Herrero, Leyre; Martínez, Mónica; Garcia-Velasco, Juan A

2011-08-01

To summarize recent advances in oocyte and embryo cryopreservation techniques and outcomes. Vitrification is gradually replacing slow freezing due to a better survival rate after thawing. Most units use vitrification for both oocyte and blastocyst cryopreservation, as these two biological structures did not perform very well with slow freezing technique. Basic experiments show that cellular damage seems lower after vitrification. Taken all together, this is helping vitirification to be expanding rapidly, and new clinical indications are being incorporated as well (i.e., fertility preservation). Cryopreservation has been used as a complement to IVF, and recent publications indicate that pregnancy rates achieved with frozen oocytes and embryos are comparable with those achieved in fresh cycles. Multiple publications studying oocyte and embryo physiology during cryopreservation have been published recently; however, larger studies are needed to verify the efficacy of new cryopreservation techniques. Vitrification is a simple and robust technique that is being incorporated into the majority of IVF units, mainly for oocyte and blastocyst cryopreservation.

Characterization of Bufo arenarum oocyte plasma membrane proteins that interact with sperm.

PubMed

Coux, Gabriela; Cabada, Marcelo O

2006-04-28

Sperm-oocyte plasma membrane interaction is an essential step in fertilization. In amphibians, the molecules involved have not been identified. Our aim was to detect and characterize oocyte molecules with binding affinity for sperm. We isolated plasma membranes free from vitelline envelope and yolk proteins from surface-biotinylated Bufo arenarum oocytes. Using binding assays we detected a biotinylated 100 kDa plasma membrane protein that consistently bound to sperm. Chromatographic studies confirmed the 100 kDa protein and detected two additional oocyte molecules of 30 and 70 kDa with affinity for sperm. Competition studies with an integrin-interacting peptide and cross-reaction with an anti-HSP70 antibody suggested that the 100 and 70 kDa proteins are members of the integrin family and HSP70, respectively. MS/MS analysis suggested extra candidates for a role in this step of fertilization. In conclusion, we provide evidence for the involvement of several proteins, including integrins and HSP70, in B. arenarum sperm-oocyte plasma membrane interactions.

Neural image analysis in the process of quality assessment: domestic pig oocytes

NASA Astrophysics Data System (ADS)

Boniecki, P.; Przybył, J.; Kuzimska, T.; Mueller, W.; Raba, B.; Lewicki, A.; Przybył, K.; Zaborowicz, M.; Koszela, K.

2014-04-01

The questions related to quality classification of animal oocytes are explored by numerous scientific and research centres. This research is important, particularly in the context of improving the breeding value of farm animals. The methods leading to the stimulation of normal development of a larger number of fertilised animal oocytes in extracorporeal conditions are of special importance. Growing interest in the techniques of supported reproduction resulted in searching for new, increasingly effective methods for quality assessment of mammalian gametes and embryos. Progress in the production of in vitro animal embryos in fact depends on proper classification of obtained oocytes. The aim of this paper was the development of an original method for quality assessment of oocytes, performed on the basis of their graphical presentation in the form of microscopic digital images. The classification process was implemented on the basis of the information coded in the form of microphotographic pictures of the oocytes of domestic pig, using the modern methods of neural image analysis.

Improved low-CPA vitrification of mouse oocytes using quartz microcapillary.

PubMed

Choi, Jung Kyu; Huang, Haishui; He, Xiaoming

2015-06-01

Cryopreservation by low-cryoprotectant (CPA) vitrification has the potential to combine all the advantages of the conventional high-CPA vitrification and slow-freezing approaches while avoiding their drawbacks. However, current low-CPA vitrification protocol for cryopreservation of oocytes requires a lengthy and multi-step procedure for unloading CPAs. In this study, we report a much-simplified procedure of using quartz microcapillary (QMC) for low-CPA vitrification of mouse oocytes with only one step for unloading CPAs. The immediate viability of oocytes after the improved low-CPA vitrification was determined to be more than 90%. Moreover, no significant difference was observed in terms of embryonic development from the two-cell to blastocyst stages between the fresh and vitrified oocytes after in vitro fertilization (IVF). This improved low-CPA vitrification technology has the potential for efficient cryopreservation of oocytes to preserve the fertility of mammals including humans for assisted reproductive medicine, maintenance of animal resource and endangered species, and livestock management. Copyright © 2015 Elsevier Inc. All rights reserved.

Purification and structural determination of an inhibitor of starfish oocyte maturation from a Bacillus species.

PubMed Central

Toraya, T; Maoka, T; Tsuji, H; Kobayashi, M

1995-01-01

Inhibitors of bacterial origins of starfish oocyte maturation were sought to obtain biologically active substances which act on either hormonal signal transduction or cell cycle regulation. An oocyte maturation-inhibiting substance found in culture fluid of a Bacillus species was purified to homogeneity. This substance possessed the nature of a detergent and specifically inhibited 1-methyladenine-induced oocyte maturation (50% inhibitory concentration, 3.3 microM) but not dithiothreitol-induced maturation. Its total structure was established to be the lactone of 3-hydroxy-13-methyltetradecanoyl-Glu-Leu-Leu-Val-Asp-Leu -Leu through COOH of the carboxy-terminal Leu. This structure is identical to surfactin, although although the configuration of the substance's amino acid residues has not yet been determined. Surfactin was shown to be identical with this substance in its inhibitory effect on starfish oocyte maturation as well as its chromatographic and electrophoretic properties. Therefore, it was concluded that the oocyte maturation-inhibiting substance produced by a Bacillus species is surfactin. PMID:7646018

Oocytes from small and large follicles exhibit similar development competence following goat cloning despite their differences in meiotic and cytoplasmic maturation.

PubMed

Yang, Min; Hall, Justin; Fan, Zhiqiang; Regouski, Misha; Meng, Qinggang; Rutigliano, Heloisa M; Stott, Rusty; Rood, Kerry A; Panter, Kip E; Polejaeva, Irina A

2016-12-01

Reduced developmental competence after IVF has been reported using oocyte derived from small follicles in several species including cattle, sheep, and goats. No information is currently available about the effect of follicle size of the cytoplast donor on in vivo development after somatic cell nuclear transfer (SCNT) in goats. Oocytes collected from large (≥3 mm) and small follicles (<3 mm) were examined for maturation and in vivo developmental competence after SCNT. Significantly greater maturation rate was observed in oocytes derived from large follicles compared with that of small follicles (51.6% and 33.7%, P < 0.05). Greater percent of large follicle oocytes exhibited a low glucose-6-phosphate dehydrogenase activity at germinal vesicle stage compared with small follicle oocytes (54.9% and 38.7%, P < 0.05). Relative mRNA expression analysis of 48 genes associated with embryonic and fetal development revealed that three genes (MATER, IGF2R, and GRB10) had higher level of expression in metaphase II oocytes from large follicles compared with oocytes from small follicles. Nevertheless, no difference was observed in pregnancy rates (33.3% vs. 47.1%) and birth rates (22.2% vs. 16.7%) after SCNT between the large and small follicle groups). These results indicate that metaphase II cytoplasts from small and large follicles have similar developmental competence when used in goat SCNT. Copyright © 2016 Elsevier Inc. All rights reserved.

A stockpile of ova in the grass frog Rana temporaria is established once for the life span. Do ovaries in amphibians and in mammals follow the same evolutionary strategy?

PubMed

Ogielska, Maria; Kotusz, Agnieszka; Augustyńska, Renata; Ihnatowicz, Jerzy; Paśko, Łukasz

2013-04-01

Most anuran amphibians produce high numbers of eggs during several consecutive breeding seasons. The question is still open whether oocytes are formed anew as a result of oogonial proliferation after each spawning or the definitive pool of oocytes is established during the juvenile period and is sufficient for the whole reproductive life span of a female. Our quantitative studies show that primary oogonia in adult female frogs can proliferate, but they fail to differentiate further and do not enter meiosis, and thereby there is no supplementation of new generations of oocytes after each spawning. Ovaries of one-year-old grass frogs contain (median) 53,447 diplotene oocytes, in two-years-old frogs this number decreased to 33,583 and eventually reached 25,679 in virgin mature females. More than 50% decrease in the total oocyte number was accompanied by massive degeneration (atresia) of oocytes. The final number of oocytes in a female forms a stock for 11-12 breeding seasons and exceeds the number of eggs produced during the potential reproductive life span of this species. The phylogenetic context of oocyte recruitment modes in the major clades of vertebrates is discussed in respect to their ability to replenish the stock (a renewable stock in ovaries named "open" vs. a non-renewable stock in ovaries named "closed"). Copyright © 2013 Wiley Periodicals, Inc.

Lectin from embryos and oocytes of Xenopus laevis. Purification and properties.

PubMed

Roberson, M M; Barondes, S H

1982-07-10

Soluble extracts of Xenopus laevis blastula stage embryos, oocytes, and adult liver contain lectin activities detected by agglutination of trypsinized, glutaraldehyde-fixed rabbit erythrocytes. Lectin from the embryos and oocytes was purified by affinity chromatography on a column derivatized with melibiose. Trace contaminants were removed either by preparative isoelectric focusing or by gel filtration. Based on its behavior on Sepharose 6B the purified oocyte lectin has an apparent molecular weight of approximately 480,000. On sodium dodecyl sulfate polyacrylamide gel electrophoresis under reducing conditions there were two major bands with molecular weight ranges of about 43,000 and 45,000, with diffuse trails. Since the purified lectin contains about 20% saccharides by weight and since both bands are glycosylated, diffuseness might be due to variable glycosylation. Heterogeneity was indicated by isoelectric focusing in polyacrylamide gels, which showed four protein bands with isoelectric points ranging from 4.4 to 4.9. Lectins from both embryos and oocytes comprised about 1 to 2% of the total soluble protein and could not be distinguished by sodium dodecyl sulfate polyacrylamide gel electrophoresis. However, the specific hemagglutination activity of the purified oocyte lectin was, on the average, 7-fold higher. Levels in crude extracts of liver were 3 orders of magnitude lower than those from oocytes. The hemagglutination activities of the lectins from embryos, oocytes, and adult liver required Ca2+ and were blocked by similar concentrations of both alpha- and beta-galactosides.

Cleavage capability of water buffalo follicular oocytes classified by cumulus cells and fertilized in vitro.

PubMed

Suzuki, T; Singla, S K; Sujata, J; Madan, M L

1991-06-01

Water buffalo (Murrah) oocytes were collected from ovaries obtained from the slaughter house. They were classified according to the character of the cumulus cells under a stereomicroscope, and cultured in 25 mM Hepes buffered Tissue Culture Medium-199 (TCM-199) supplemented with 5% estrous water buffalo serum in an atmosphere containing 5% CO2 in air at 39 degrees C. After 20-24 hr of in vitro maturation, the oocytes were fertilized using capacitated sperm obtained from 4 different bulls. For cleavage the oocytes were cultured at 39 degrees C in TCM-199 supplemented with 1% estrous water buffalo serum and in an atmosphere containing 5% CO2 in air. The good oocytes, with compact and dense cumulus cells cleaved significantly higher (p less than 0.01, 67.3%), than those of fair. partially naked oocytes with thin cumulus layers (27.5%, 25/91) or small remnants of cumulus cells and poor naked oocytes (3/100). A substantial variation cumulus layers (27.5% 25/91) or small remnants of cumulus cells and poor naked oocytes (3/100). A substantial variation in fertilization and developmental rates (16.0% to 43.8%) was observed among 4 different bulls. Late non-surgically into 14 buffalo recipients on day 6 or 7 of their estrous cycle. One recipient was diagnosed to be pregnant by rectal palpation on day 60 and confirmed to be so on day 90 post-estrus.

Stability of the cytoskeleton of matured buffalo oocytes pretreated with cytochalasin B prior to vitrification.

PubMed

Wang, C L; Xu, H Y; Xie, L; Lu, Y Q; Yang, X G; Lu, S S; Lu, K H

2016-06-01

Stabilizing the cytoskeleton system during vitrification can improve the post-thaw survival and development of vitrified oocytes. The cytoskeleton stabilizer cytochalasin B (CB) has been used in cryopreservation to improve the developmental competence of vitrified oocytes. To assess the effect of pretreating matured buffalo oocytes with CB before vitrification, we applied 0, 4, 8, or 12 μg/mL CB for 30 min. The optimum concentration of CB treatment (8 μg/mL for 30 min) was then used to evaluate the distribution of microtubules and microfilaments, the expression of the cytoskeleton proteins actin and tubulin, and the developmental potential of matured oocytes that were vitrified-warmed by the Cryotop method. Western blotting demonstrated that vitrification significantly decreased tubulin expression, but that the decrease was attenuated for oocytes pretreated with 8 μg/mL CB before vitrification. After warming and intracytoplasmic sperm injection, oocytes that were pretreated with 8 μg/mL CB before vitrification yielded significantly higher 8-cell and blastocyst rates than those that were vitrified without CB pretreatment. The values for the vitrified groups in all experiments were significantly lower (P < 0.01) than those of the control groups. In conclusion, pretreatment with 8 μg/mL CB for 30 min significantly improves the cytoskeletal structure, expression of tubulin, and development capacity of vitrified matured buffalo oocytes. Copyright © 2016 Elsevier Inc. All rights reserved.

Autoimmune abnormality affects ovulation and oocyte-pick-up in MRL/MpJ-Fas lpr/lpr mice.

PubMed

Hosotani, M; Ichii, O; Nakamura, T; Kanazawa, S O; Elewa, Y Hosny Ali; Kon, Y

2018-01-01

Ovulation and oocyte-pick-up are essential processes in fertilization. Herein, we found associations between autoimmune disease and the aforementioned processes in mice. At three and six months, along with the evaluation of autoimmune disease indices, the ovary, mesosalpinx, and oviducts were histologically examined in C57BL/6, MRL/MpJ, and MRL/MpJ-Fas lpr/lpr mice as healthy control, mild and severe models of autoimmune disease, respectively. In superovulated mice, the number of "oocyte cumulus complexes" found in the ampulla was macroscopically counted, and that of "ovulated oocytes" was histologically evaluated, as indicated by ruptured follicles or corpora hemorrhagica in ovaries. Finally, the oocyte-pick-up rate was calculated. In MRL/MpJ-Fas lpr/lpr mice, the oocyte-pick-up rate decreased with disease-related deterioration, unlike in other mouse strains. Further, more ovulated oocytes were found in MRL/MpJ mice than in C57BL/6 mice, and this number significantly decreased with aging in MRL/MpJ-Fas lpr/lpr mice. Numerous T-cells infiltrated into the infundibulum or a part of the mesosalpinx in aged MRL/MpJ-Fas lpr/lpr mice, and their infundibulum showed swelling and fewer ciliated epithelial cells compared to that of C57BL/6 mice. In conclusion, the progression of severe autoimmune disease affected the oocyte-pick-up process through histopathological changes in the infundibulum. These results provide important insights into female infertility associated with autoimmune disease.

Zona pellucida from fertilised human oocytes induces a voltage-dependent calcium influx and the acrosome reaction in spermatozoa, but cannot be penetrated by sperm

PubMed Central

Patrat, Catherine; Auer, Jana; Fauque, Patricia; Leandri, Roger L; Jouannet, Pierre; Serres, Catherine

2006-01-01

Background The functions of three zona glycoproteins, ZP1, ZP2 and ZP3 during the sperm-zona pellucida (ZP) interaction are now well established in mice. The expression of an additional zona glycoprotein, ZPB/4, in humans, led us to reconsider the classical mouse model of gamete interaction. We investigated the various functions of human ZP (hZP) during the interaction of spermatozoa with fertilised and unfertilised oocytes. Results The hZP of fertilised oocytes retained their ability to bind sperm (albeit less strongly than that from unfertilised oocytes), to induce an intraspermatic calcium influx through voltage-dependent channels similar to that observed with hZP from unfertilised oocytes and to promote the acrosome reaction at a rate similar to that induced by the ZP of unfertilised oocytes (61.6 ± 6.2% vs60.7 ± 9.1% respectively). Conversely, the rate of hZP penetrated by sperm was much lower for fertilised than for unfertilised oocytes (19% vs 57% respectively, p < 0.01). We investigated the status of ZP2 in the oocytes used in the functional tests, and demonstrated that sperm binding and acrosome reaction induction, but not ZP penetration, occurred whether or not ZP2 was cleaved. Conclusion The change in ZP function induced by fertilisation could be different in human and mouse species. Our results suggest a zona blocking to polyspermy based at the sperm penetration level in humans. PMID:17147816

Participation of inositol trisphosphate and ryanodine receptors in Bufo arenarum oocyte activation.

PubMed

Ajmat, M T; Bonilla, F; Zelarayán, L; Bühler, M I

2011-05-01

Calcium is considered the most important second messenger at fertilization. Transient release from intracellular stores is modulated through both agonist-gated channels, IP₃Rs and RyRs, which can be found individually or together depending on the oocyte species. Using the four commonly used compounds (thimerosal, caffeine, heparin and ruthenium red), we investigated the existence and interdependence of both IP₃Rs and RyRs in mature Bufo arenarum oocytes. We found that caffeine, a well known specific RyRs agonist, was able to trigger oocyte activation in a dose-dependent manner. Microinjection of 10 mM caffeine showed 100% of oocytes exhibiting characteristic morphological criteria of egg activation. Ruthenium red, the specific RyR blocker, was able to inhibit oocyte activation induced either by sperm or caffeine. Our present findings provide the first reported evidence of the existence of RyR in frogs. We further explored the relationship between IP₃Rs and RyRs in B. arenarum oocytes by exposing them to the agonists of one class after injecting a blocker of the other class of receptor. We found that thimerosal overcame the inhibitory effect of RyR on oocyte activation, indicating that IP₃Rs function as independent receptors. In contrast, previous injection of heparin delayed caffeine-induced calcium release, revealing a relative dependence of RyRs on functional IP₃Rs, probably through a CICR mechanism. Both receptors play a role in Ca²+ release mechanisms although their relative contribution to the activation process is unclear.

Differential nuclear remodeling of mammalian somatic cells by Xenopus laevis oocyte and egg cytoplasm

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alberio, Ramiro; Johnson, Andrew D.; Stick, Reimer

2005-07-01

The mechanisms governing nuclear reprogramming have not been fully elucidated yet; however, recent studies show a universally conserved ability of both oocyte and egg components to reprogram gene expression in somatic cells. The activation of genes associated with pluripotency by oocyte/egg components may require the remodeling of nuclear structures, such that they can acquire the features of early embryos and pluripotent cells. Here, we report on the remodeling of the nuclear lamina of mammalian cells by Xenopus oocyte and egg extracts. Lamin A/C is removed from somatic cells incubated in oocyte and egg extracts in an active process that requiresmore » permeable nuclear pores. Removal of lamin A/C is specific, since B-type lamins are not changed, and it is not dependent on the incorporation Xenopus egg specific lamin III. Moreover, transcriptional activity is differentially regulated in somatic cells incubated in the extracts. Pol I and II transcriptions are maintained in cells in oocyte extracts; however, both activities are abolished in egg extracts. Our study shows that components of oocyte and egg extracts can modify the nuclear lamina of somatic cells and that this nuclear remodeling induces a structural change in the nucleus which may have implications for transcriptional activity. These experiments suggest that modifications in the nuclear lamina structure by the removal of somatic proteins and the incorporation of oocyte/egg components may contribute to the reprogramming of somatic cell nuclei and may define a characteristic configuration of pluripotent cells.« less

Trichloroethylene Metabolism in the Rat Ovary Reduces Oocyte Fertilizability

PubMed Central

Wu, Katherine Lily; Berger, Trish

2007-01-01

Exposure to trichloroethylene (TCE, an environmental toxicant) reduced oocyte fertilizability in the rat. In vivo, TCE may be metabolized by cytochrome P450 dependent oxidation or glutathione conjugation in the liver or kidneys, respectively. Cytochrome P450 dependent oxidation is the higher affinity pathway. The primary isoform of cytochrome P450 to metabolize TCE in the liver, cytochrome P450 2E1, is present in the rodent ovary. Ovarian metabolism of TCE by the oxidative pathway and the production of reactive oxygen species may occur given the presence of the metabolizing enzyme. The objectives of this study were to define the sensitive interval of oocyte growth to TCE exposure, and to determine if TCE exposure resulted in the formation of ovarian protein carbonyls, an indicator of oxidative damage. Rats were exposed to TCE in drinking water (0.45% TCE (v/v) in 3% Tween) or 3% Tween (vehicle-control) during three 4–5 day intervals of oocyte development preceding ovulation. Oocytes from TCE-exposed females were less fertilizable compared with vehicle-control oocytes. Immunohistochemical labeling of ovaries and Western blotting of ovarian proteins demonstrated TCE treatment induced a greater incidence of protein carbonyls compared with vehicle controls. Protein carbonyl formation in the ovary is consistent with TCE metabolism by the cytochrome P450 pathway. Oxidative damage following ovarian TCE metabolism or the presence of TCE metabolites may contribute to reduced oocyte fertilizability. In summary, these results indicate maturing oocytes are susceptible to very short in vivo exposures to TCE. PMID:17673192

Estimation of the optimal timing of fertilization for embryo development of in vitro-matured bovine oocytes based on the times of nuclear maturation and sperm penetration.

PubMed

Koyama, Keisuke; Kang, Sung-Sik; Huang, Weiping; Yanagawa, Yojiro; Takahashi, Yoshiyuki; Nagano, Masashi

2014-05-01

The objective of this research was to estimate the optimal timing for fertilization to achieve proper embryonic development of in vitro-matured bovine oocytes. First, cumulus-oocyte complexes were subjected to in vitro maturation (IVM) for 14-22 hr. The timing when 50% of oocytes reached metaphase II stage was estimated to be 17.5 hr after IVM start. Next, using oocytes subjected to IVM for 12-30 hr, sperm penetration was examined after 4-18 hr of in vitro fertilization (IVF). A significant negative correlation between IVM duration and the timing when 50% of oocytes were penetrated by sperm after IVF start was observed (P<0.01). Finally, oocytes subjected to 12-30 hr of IVM were inseminated and cultured for 6 days to examine embryonic development. In the group with 22 hr of IVM, the percentages of cleaved embryos and blastocysts were the highest values in all groups. According to the regression equation describing the time from nuclear maturation to sperm penetration (x) and the percentage of blastocysts (y) (y=7.23x - 0.297x(2), P<0.01), the blastocyst rate peaked when sperm penetration occurred at 12.2 hr after achieving nuclear maturation. In conclusion, under the present IVM/IVF conditions, it was estimated that oocytes acquired their highest developmental competence at about 30 hr after IVM start, and thus, the optimal IVM duration was calculated to be about 21 hr.

Discovery of 5R-lipoxygenase activity in oocytes of the surf clam, Spisula solidissima.

PubMed

Hada, T; Swift, L L; Brash, A R

1997-06-02

Arachidonic acid and 5-hydroxyeicosatetraenoic acid (5-HETE) are reported to induce reinitiation of meiosis in oocytes of the surf clam Spisula sachalinensis from the Sea of Japan (Varaksin et al., Comp. Biochem. Physiol. 101C, 627-630 (1992). As the Atlantic surf clam Spisula solidissima is a commonly used model for the study of meiosis reinitiation, we examined these cells for the possible occurrence of lipoxygenases and for the bioactivity of the products. Incubation of [14C]arachidonic acid with homogenates of S. solidissima oocytes led to the formation of two major metabolites: 5R-HETE, a novel lipoxygenase product, and 8R-HETE. The products were identified by HPLC, uv spectroscopy, and GC-MS. The corresponding hydroperoxy fatty acids, the primary lipoxygenase products, were isolated from incubations of ammonium sulfate fractionated oocyte cytosol. Arachidonic and eicosapentaenoic acids were identified as constituents of S. solidissima oocyte lipids and the free acids were equally good lipoxygenase substrates. We examined the activity of C18 and C20 polyunsaturated fatty acids and their lipoxygenase products on meiosis reinitiation in Spisula solidissima oocytes, using serotonin and ionophore A23187 as positive controls. The fatty acids and their derivatives were inactive. We conclude that in the surf clam, (as in starfish), there are responding and non-responding species in regard to the maturation-inducing activity of the oocyte lipoxygenase products, and that the lipoxygenase has another, as yet uncharacterized, function in oocyte physiology.

Chronic unpredictable stress decreases expression of brain-derived neurotrophic factor (BDNF) in mouse ovaries: relationship to oocytes developmental potential.

PubMed

Wu, Li-Min; Hu, Mei-Hong; Tong, Xian-Hong; Han, Hui; Shen, Ni; Jin, Ren-Tao; Wang, Wei; Zhou, Gui-Xiang; He, Guo-Ping; Liu, Yu-Sheng

2012-01-01

Brain-derived neurotropic factor (BDNF) was originally described in the nervous system but has been shown to be expressed in ovary tissues recently, acting as a paracrine/autocrine regulator required for developments of follicles and oocytes. Although it is generally accepted that chronic stress impairs female reproduction and decreases the expression of BDNF in limbic structures of central nervous system, which contributes to mood disorder. However, it is not known whether chronic stress affects oocytes developments, nor whether it affects expression of BDNF in ovary. Mice were randomly assigned into control group, stressed group, BDNF-treated group and BDNF-treated stressed group. The chronic unpredictable mild stress model was used to produce psychosocial stress in mice, and the model was verified by open field test and hypothalamic-pituitary-adrenal (HPA) axis activity. The methods of immunohistochemistry and western blotting were used to detect BDNF protein level and distribution. The number of retrieved oocytes, oocyte maturation, embryo cleavage and the rates of blastocyst formation after parthenogenetic activation were evaluated. Chronic unpredictable stress decreased the BDNF expression in antral follicles, but didn't affect the BDNF expression in primordial, primary and secondary follicles. Chronic unpredictable stress also decreased the number of retrieved oocytes and the rate of blastocyst formation, which was rescued by exogenous BDNF treatment. BDNF in mouse ovaries may be related to the decreased number of retrieved oocytes and impaired oocytes developmental potential induced by chronic unpredictable stress.

Chronic Unpredictable Stress Decreases Expression of Brain-Derived Neurotrophic Factor (BDNF) in Mouse Ovaries: Relationship to Oocytes Developmental Potential

PubMed Central

Tong, Xian-Hong; Han, Hui; Shen, Ni; Jin, Ren-Tao; Wang, Wei; Zhou, Gui-Xiang; He, Guo-Ping; Liu, Yu-Sheng

2012-01-01

Background Brain-derived neurotropic factor (BDNF) was originally described in the nervous system but has been shown to be expressed in ovary tissues recently, acting as a paracrine/autocrine regulator required for developments of follicles and oocytes. Although it is generally accepted that chronic stress impairs female reproduction and decreases the expression of BDNF in limbic structures of central nervous system, which contributes to mood disorder. However, it is not known whether chronic stress affects oocytes developments, nor whether it affects expression of BDNF in ovary. Methods Mice were randomly assigned into control group, stressed group, BDNF-treated group and BDNF-treated stressed group. The chronic unpredictable mild stress model was used to produce psychosocial stress in mice, and the model was verified by open field test and hypothalamic-pituitary-adrenal (HPA) axis activity. The methods of immunohistochemistry and western blotting were used to detect BDNF protein level and distribution. The number of retrieved oocytes, oocyte maturation, embryo cleavage and the rates of blastocyst formation after parthenogenetic activation were evaluated. Results Chronic unpredictable stress decreased the BDNF expression in antral follicles, but didn’t affect the BDNF expression in primordial, primary and secondary follicles. Chronic unpredictable stress also decreased the number of retrieved oocytes and the rate of blastocyst formation, which was rescued by exogenous BDNF treatment. Conclusion BDNF in mouse ovaries may be related to the decreased number of retrieved oocytes and impaired oocytes developmental potential induced by chronic unpredictable stress. PMID:23284991

Interfering effects of bisphenol A on in vitro growth of preantral follicles and maturation of oocyes.

PubMed

Wang, Xiyan; Jiang, Shi-Wen; Wang, Liguo; Sun, Yanmei; Xu, Fangyan; He, Hai; Wang, Shuo; Zhang, Zhenghong; Pan, Xiaoyan

2018-06-26

In order to investigate the effects and mechanism of Bisphenol A (BPA) on the growth of preantral follicles and the maturation of oocytes in vitro, preantral follicles were harvested from mouse ovaries and in vitro cultured for 11 days with different concentrations of BPA (0, 4.5 and 45 μM) for calculating the percentages of antral follicles, denuded oocytes, degenerative oocytes and the maturation rate of oocytes, besides measuring the diameter of follicles and the thickness of cumulus cell layers. The contents of estradiol (E 2 ) in the culture media on Day 4, 8 and 10 were detected by ELISA. The estrogen receptor (ER) expression, spindle morphology and chromosome distribution in oocytes on Day 10 and 11 were observed by immunofluorescence. Western blotting was used to detect the expressions of growth differentiation factor 9 (GDF-9), bone morphogenetic protein-15 (BMP-15), phosphorylated extracellular signal-regulated kinase 1 (p-Erk1) and phosphorylated Ca 2 + /calmodulin-dependent protein kinase II (p-CaMKII) in the oocytes. Compared with control, BPA (45 μM) significantly reduced percentages of antral follicles (9.25% vs. 91.17%, P < 0.05) and the maturation rate of oocytes (7.61% vs. 79.83%, P < 0.05), but increased the percentages of denuded oocytes (30.29% vs. 3.36%, P < 0.05) and degenerative oocytes (45.70% vs. 2.45%, P < 0.05). The diameter of follicles and the thickness of the cumulus cell layers were decreased significantly (P < 0.05). Moreover, BPA (45 μM) significantly decreased E 2 contents in the culture medium on Day 8 and 10 (P < .05) and the expressions of ER, GDF-9 and BMP-15 in oocytes (P < 0.05). Furthermore, BPA (4.5 and 45 μM) treatment resulted in the abnormal spindle morphology and chromosome distribution, and the decreased expressions of p-Erk1 and p-CaMKII in the MII oocytes. Together, these results clearly demonstrated BPA retarded the preantral follicle growth in vitro through interfering with the synthesis and secretion of E 2 and reducing the expressions of ER, GDF-9 and BMP-15, and led to the abnormal meioses of oocytes through reducing p-Erk1 and p-CaMKII expressions in the preantral follicles, which will help us to further unsderstand the mechanism of BPA exposure retarding in vitro growth of preantral follicles and maturation of oocyes. Copyright © 2018. Published by Elsevier B.V.

Evaluation of bovine (Bos indicus) ovarian potential for in vitro embryo production in the Adamawa plateau (Cameroon)

PubMed Central

Kouamo, J.; Dawaye, S.M.; Zoli, A.P.; Bah, G.S.

2014-01-01

An abattoir study was conducted to evaluate the ovarian potential of 201 local zebu cattle from Ngaoundere, Adamawa region (Cameroon) for in vitro embryo production (IVEP). The ovaries were excised, submerged in normal saline solution (0.9%) and transported to the laboratory for a detailed evaluation. Follicles on each ovary were counted, their diameters (Φ) measured and were grouped into 3 categories: small (Φ < 3 mm), medium (3 ≥ Φ ≤ 8 mm) and large (Φ > 8 mm). Each ovary was then sliced into a petri dish; the oocytes were recovered in Dulbecco’s phosphate buffered saline, examined under a stereoscope (x10) and graded into four groups based on the morphology of cumulus oophorus cells and cytoplasmic changes of the oocytes. Grade I (GI): oocytes with more than 4 layers of bunch of compact cumulus cells mass with evenly granulated cytoplasm; grade II (GII): oocyte with at least 2-4 layers of compact cumulus cell mass with evenly granulated cytoplasm; grade III (GIII): oocyte with at least one layer of compact cumulus cell mass with evenly granulated cytoplasm; grade IV (GIV): denuded oocyte with no cumulus cells or incomplete layer of cumulus cell or expanded cells and having dark or unevenly granulated cytoplasm. The effects of both ovarian (ovarian localization, corpus luteum, size and weight of ovary) and non-ovarian factors (breed, age, body condition score (BCS) and pregnancy status of cow) on the follicular population and oocyte recovery rate were determined. There were an average of 16.75±0.83 follicles per ovary. The small, medium and large follicles were 8.39±0.60, 8.14±0.43 and 0.21±0.02 respectively. Oocyte recovery was 10.97±0.43 per ovary (65%). Oocytes graded I, II, III and IV were 3.53±0.19 (32.21%), 2.72±0.15 (24.82%), 2.24±0.15 (20.43%) and 2.47±0.20 (22.54%) respectively. The oocyte quality index was 2.26. Younger non pregnant cows having BCS of 3 and large ovaries presented higher number of follicles and oocyte quality (P < 0.05) compared with other animals. Oocytes with quality (grade I and II) acceptable for IVEP constituted 57.15% of the harvest. This study indicated that factors such as age, pregnancy status, BCS and ovarian size must be taken into account to increase the potential of the ovary for IVEP. PMID:26623353

Outcome of ICSI with motile testicular spermatozoa obtained through microscopically assisted testicular sperm extraction in relation to the ovarian response.

PubMed

Erdem, E; Karacan, M; Usta, A; Arvas, A; Cebi, Z; Camlibel, T

2017-05-01

To determine the relationship between AFC, basal FSH level, woman's age, the number of oocytes retrieved and the outcome of ICSI with testicular spermatozoa obtained with microscopically assisted testicular sperm extraction. In this retrospective cohort study, a total of 340 couples who underwent ICSI treatment with testicular sperm were enrolled. Women aged?40years and the first cycles of couples were included. ICSI was performed with motile testicular spermatozoa obtained from 89 men with obstructive azoospermia and 251 men with nonobstructive azoospermia. GnRH-antagonist protocol was used for ovulation induction. Simple linear regression was carried out to analyze relationship between the AFC, basal FSH, woman's age, the number of oocytes, and the live birth rate (LBR). Receiver operator characteristic curves (ROC) were formed to detect cut-off values below which LBR was significantly decreased. ROC curve analysis demonstrated that the cut-off level of the number of oocytes retrieved to predict the LBR was 7. According to this cut-off level, all patients were divided into two groups. Women with retrieved<7 oocytes were included in Group 1 and women with retrieved?7 oocytes were included in Group 2. The mean age of men was 35.1±4.9years. The mean age, mean FSH level and mean AFC of women were 32.1±4.9years, 6.9±2.7 IU/L, 7.6±3.4, respectively. Significant correlations were found between AFC, the number of oocytes retrieved, and the LBR per ICSI cycle with testicular spermatozoa. The LBR was significantly lower in women with AFC<8 than those with AFC?8. Independently, the LBR was significantly lower in cycles with<7 oocytes retrieved compared to those with ?7. Embryo transfer was not achieved in 37 cycles with<7 oocytes (37/167, 22.1%) and 18 cycles with?7 (18/173, 10.4%) because of the absence of transfer-quality embryos (P=0.005). The LBRs were the lowest in cycles with one or two oocytes available (8.3 and 8.3%, respectively), but these rates were not statistically different than those in cycles with 3, 4, 5 and 6 oocytes (14.2, 17.2, 18.5, 17.6%, respectively, P=0.810). AFC and the number of oocytes retrieved are important prognostic factors in an ICSI cycle with testicular sperm in women ?40years, yielding significantly diminished LBRs with<8 antral follicles and/or<7 oocytes retrieved. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Follicular progesterone concentrations and messenger RNA expression of MATER and OCT-4 in immature bovine oocytes as predictors of developmental competence.

PubMed

Urrego, R; Herrera-Puerta, E; Chavarria, N A; Camargo, O; Wrenzycki, C; Rodriguez-Osorio, N

2015-04-15

The ability of bovine embryos to develop to the blastocyst stage and to implant and generate healthy offspring depends greatly on the competence of the oocyte. Oocyte competence is attributed to its close communication with the follicular environment and to its capacity to synthesize and store substantial amounts of messenger RNA. Higher developmental competence of bovine oocytes has been associated with both the expression of a cohort of developmental genes and the concentration of sex steroids in the follicular fluid. The aim of this study was to identify differences in the expression of FST in cumulus cells and OCT-4 and MATER in oocytes and the influence of the follicular progesterone and follicular estrogen concentration on the competence of bovine oocytes retrieved 30 minutes or 4 hours after slaughter. Cumulus-oocyte complexes (COCs) were left in postmortem ovaries for 30 minutes (group I) or 4 hours (group II) at 30 °C. Aspirated oocytes were then subjected to IVM, IVF, and IVC or were evaluated for MATER and OCT-4 messenger RNA abundance by quantitative real-time polymerase chain reaction. Total RNA was isolated from pools of 100 oocytes for each experimental replicate. Progesterone and estradiol concentration in follicular fluid was evaluated by immunoassay using an IMMULITE 2000 analyzer. Three repeats of in vitro embryo production were performed with a total of 455 (group I) and 470 (group II) COCs. There were no significant differences between the cleavage rates (72 hours postinsemination [hpi]) between both groups (63.5% vs. 69.1%). However, blastocyst (168 hpi) and hatching (216 hpi) rates were higher (P < 0.05) in group II compared with those of group I (21.3% vs. 30.7% and 27.6% vs. 51.5%, respectively). Group II oocytes exhibited the highest MATER and OCT-4 abundance (P < 0.05). Follicular estradiol concentration was not different between both the groups, whereas the progesterone concentration was lower (P ≤ 0.05) in group II follicles. These results indicate that retrieving COCs 4 hours after slaughter could increase bovine in vitro developmental competence, which is linked to higher levels of oocyte MATER and OCT-4 transcripts and lower follicular progesterone concentration. Moreover, the results of the present study contribute to the identification of factors involved in the developmental competence of immature oocytes. Copyright © 2015 Elsevier Inc. All rights reserved.

CONCENTRATION DEPENDENT ACCUMULATION OF [3H]-DELTAMETHRIN IN SODIUM CHANNEL N AV1.2 EXPRESSING XENOPUS LAEVIS OOCYTES.

EPA Science Inventory

Disruption of neuronal voltage-sensitive sodium channels (VSSCs) by pyrethroid insecticides such as deltamethrin (DLT) has been widely studied using Xenopus laevis oocytes transfected with VSSC. However, the extent of pyrethroid accumulation in VSSC-expressing oocytes is unknown....

Obesity modulates inflammation and lipid metabolism oocyte gene expression: A single cell transcriptome perspective

USDA-ARS?s Scientific Manuscript database

This study aimed to compare oocyte gene expression profiles and follicular fluid (FF) content from overweight/obese (OW) women and normal weight (NW) women who were undergoing fertility treatments. Using single cell transcriptomic analyses, we investigated oocyte gene expression using RNA-seq. Serum...

DNA (DEOXYRIBONUCLEIC ACID) SYNTHESIS FOLLOWING MICROINJECTION OF HETEROLOGOUS SPERM AND SOMATIC CELL NUCLEI INTO HAMSTER OOCYTES

EPA Science Inventory

The authors have investigated the ability of the hamster oocyte to initiate DNA synthesis in nuclei differing in basic protein content. DNA synthesis was studied by autoradiography in oocytes that had been incubated in 3H-thymidine after being parthenogenetically activated by sha...

Oocyte donation for reproduction and research cloning--the perils of commodification and the need for European and international regulation.

PubMed

Schneider, Ingrid

2006-01-01

The demand for women's egg cells is increasing and is leading to reproductive tourism and transnational oocyte trafficking. The article considers the regulatory landscape of oocyte donation in Europe and analyses different types, particularly whether oocytes are provided within or outside of the IVF context, and whether anonymity of the donor is legally possible or not. The bifurcation between different purposes of egg extraction, particularly the challenges raised by ova demands for cloning research (SCNT) are highlighted. In emphasizing the need for supranational regulation, nine rules for supranational minimum standards are proposed to protect both donor interests and the public good. A particular focus is directed to the commodification of oocytes with regard to the European principle of non-commercial, voluntary and altruistic donation.

Ovarian reserve and response to stimulation in women undergoing fertility preservation according to malignancy type.

PubMed

Lefebvre, Tiphaine; Mirallié, Sophie; Leperlier, Florence; Reignier, Arnaud; Barrière, Paul; Fréour, Thomas

2018-05-02

Does ovarian reserve and ovarian response to ovarian stimulation in women with cancer undergoing oocyte vitrification for fertility preservation vary according to the type of malignancy? Retrospective cohort study including 105 women aged between 18 and 40 years, who were referred for fertility preservation (oocyte vitrification) between 2013 and 2016. The women were divided into three groups: breast cancer, lymphoma or other cancer. All of them had been recently diagnosed with cancer, with gonadotoxic treatment scheduled, and had oocyte vitrification after ovarian stimulation with antagonist protocol. Baseline antral follicle count and anti-Müllerian hormone were no different between women with breast cancer, lymphoma or other cancer. The number of cancelled cycles for poor ovarian response was similar between the groups. The number of FSH units per mature oocyte, the number of mature oocytes (metaphase II) retrieved, and the oocyte maturity rate were not significantly different between the three groups. As the type of cancer does not seem to significantly affect ovarian reserve and ovarian response to ovarian stimulation, our results do not support the relevance of integrating this parameter when establishing ovarian stimulation protocol for oocyte vitrification cycle in women with cancer. Copyright © 2018 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

Bovine oocytes with the potential to reprogram somatic cell nuclei have a unique 23-kDa protein, phosphorylated transcriptionally controlled tumor protein (TCTP).

PubMed

Tani, Tetsuya; Shimada, Hiroaki; Kato, Yoko; Tsunoda, Yukio

2007-01-01

Despite the long-held assumption that reprogramming factors are present in mammalian oocytes at the second metaphase stage, the molecular nature of these factors is not known. Here, we demonstrated that oocytes with the potential to reprogram somatic cell nuclei have a unique 23-kDa protein, phosphorylated transcriptionally controlled tumor protein (TCTP). Injection of TCTP double-stranded RNA into germinal vesicle oocytes decreased the potential of nuclear-transferred (NT) oocytes, but not in vitro fertilized oocytes, to develop into blastocysts. Phosphorylated TCTP is considered to facilitate the first step of somatic cell reprogramming. After transfer of blastocysts that developed from NT oocytes fused with cumulus cells in which phosphorylated TCTP peptide was previously incorporated, the recipient pregnancy rate (47%) increased and the abortion rate (13%) decreased. Moreover, all seven cloned calves survived for at least 1 month after parturition, and had no morphologic abnormalities. The present study demonstrated that pretreatment of donor cells with phosphorylated TCTP peptide has a beneficial effect on the potential of bovine somatic cell nuclei to develop into normal cloned calves. Before widespread application of TCTP for bovine cloning, however, a large-scale embryo transfer study using different donor cell lines of various origins is necessary.

Error-prone meiotic division and subfertility in mice with oocyte-conditional knockdown of pericentrin.

PubMed

Baumann, Claudia; Wang, Xiaotian; Yang, Luhan; Viveiros, Maria M

2017-04-01

Mouse oocytes lack canonical centrosomes and instead contain unique acentriolar microtubule-organizing centers (aMTOCs). To test the function of these distinct aMTOCs in meiotic spindle formation, pericentrin (Pcnt), an essential centrosome/MTOC protein, was knocked down exclusively in oocytes by using a transgenic RNAi approach. Here, we provide evidence that disruption of aMTOC function in oocytes promotes spindle instability and severe meiotic errors that lead to pronounced female subfertility. Pcnt-depleted oocytes from transgenic (Tg) mice were ovulated at the metaphase-II stage, but show significant chromosome misalignment, aneuploidy and premature sister chromatid separation. These defects were associated with loss of key Pcnt-interacting proteins (γ-tubulin, Nedd1 and Cep215) from meiotic spindle poles, altered spindle structure and chromosome-microtubule attachment errors. Live-cell imaging revealed disruptions in the dynamics of spindle assembly and organization, together with chromosome attachment and congression defects. Notably, spindle formation was dependent on Ran GTPase activity in Pcnt-deficient oocytes. Our findings establish that meiotic division is highly error-prone in the absence of Pcnt and disrupted aMTOCs, similar to what reportedly occurs in human oocytes. Moreover, these data underscore crucial differences between MTOC-dependent and -independent meiotic spindle assembly. © 2017. Published by The Company of Biologists Ltd.

Human oocyte cryopreservation.

PubMed

Tao, Tao; Zhang, Wenling; Del Valle, Alfonso

2009-06-01

This review summarized the clinical breakthroughs in the human oocyte cryopreservation field in the past 2 years and gave special emphasis on the role of vitrification method. Human oocyte cryopreservation is an attractive strategy to preserve female fertility, as it offers more opportunities to the future destination of the female gametes and also raises fewer legal and ethical questions compared with embryo cryopreservation. It became promising in recent years because of dramatic improvement in cryopreservation technologies. Human oocyte cryopreservation would not become a clinical routine until the availability of reliable cryopreservation methods and long-term follow-up results of the babies born by this technique. Oocyte cryopreservation produced very exciting results with pregnancy and implantation rates comparable to embryo cryopreservation and in some cases comparable to fresh in-vitro fertilization cycles with both modified slow-freezing and vitrification methods. A cancer patient conceived and delivered her own babies by this technology after recovery from the disease. Oocyte cryopreservation became a new focus in assisted reproductive technology. We witnessed the advanced development of human oocyte cryopreservation in the past years because of increasing demand, medically, legally and ethically, and also because of the dramatic improvement of the freezing technique. There is still a long way to go to integrate it into a routine clinical procedure to benefit more patients and encourage clinicians to follow the standard protocols.

Involvement of estradiol-17beta and its membrane receptor, G protein coupled receptor 30 (GPR30) in regulation of oocyte maturation in zebrafish, Danio rario.

PubMed

Pang, Yefei; Thomas, Peter

2009-03-01

The orphan G protein coupled receptor, GPR30, has the characteristics of a high affinity, specific estrogen membrane receptor on Atlantic croaker oocytes and mediates estrogen inhibition of oocyte maturation in this perciform fish. In order to determine the broad applicability of these findings to other teleosts, similar experiments were conducted in a cyprinid fish, zebrafish, in the present study. GPR30 mRNA expression was detected in zebrafish oocytes but not in the ovarian follicular cells. Both spontaneous and 17, 20beta-dihyroxy-4-pregnen-3-one (DHP)-induced maturation of follicle-enclosed zebrafish oocytes was significantly decreased when they were incubated with either estradiol-17beta, or the GPR30 agonists, ICI 182 780 and tamoxifen, or with the GPR30 specific agonist G-1. On the other hand spontaneous oocyte maturation increased two-fold when zebrafish ovarian follicles were incubated with an aromatase inhibitor, ATD. Moreover, the stimulatory effects of ATD on germinal vesicle breakdown (GVBD) were partially reversed by co-treatment with 100 nM of E2 or G-1. These results suggest that endogenous estrogens acting through GPR30 are involved in maintaining meiotic arrest of zebrafish oocytes.

Mechanical stimulation by osmotic and hydrostatic pressure activates Drosophila oocytes in vitro in a calcium-dependent manner

PubMed Central

Horner, Vanessa L.; Wolfner, Mariana F.

2008-01-01

Summary Embryogenesis in vertebrates and marine invertebrates begins when a mature oocyte is fertilized, resulting in a rise in intracellular calcium (Ca2+) that activates development. Insect eggs activate without fertilization via an unknown signal imparted to the egg during ovulation or egg laying. One hypothesis for the activating signal is that deformation of eggs as they pass through a tight orifice provides a mechanical stimulus to trigger activation. Ovulation could produce two forms of mechanical stimulus: external pressure resulting from the passage of oocytes from the ovary into the narrow oviducts, and osmotic pressure caused by hydration-induced swelling of the oocyte within the oviducts. Ovulation could also trigger activation by placing the oocyte in a new environment that contains an activating substance, such as a particular ion. Here, we provide the first evidence that Drosophila oocytes require Ca2+ for activation, and that activation can be triggered in vitro by mechanical stimuli, specifically osmotic and hydrostatic pressure. Our results suggest that activation in Drosophila is triggered by a mechanosensitive process that allows external Ca2+ to enter the oocyte and drive the events of activation. This will allow exploitation of Drosophila genetics to dissect molecular pathways involving Ca2+ and the activation of development. PMID:18304524

MPK-1/ERK regulatory network controls the number of sperm by regulating timing of sperm-oocyte switch in C. elegans germline.

PubMed

Yoon, Dong Suk; Alfhili, Mohammad A; Friend, Kyle; Lee, Myon-Hee

2017-09-30

The precise regulation of germline sexual fate is crucial for animal fertility. In C. elegans, the production of either type of gamete, sperm or oocyte, becomes mutually exclusive beyond the larval stage. Hermaphrodites initially produce sperm and then switch to produce oocytes. This change of fate during germline development is tightly controlled by several regulators. In C. elegans hermaphrodites, FBF-1 and FBF-2 (>95% identical, members of the Pumilio RNA-binding protein family) proteins function redundantly to promote the sperm-oocyte switch. Here, we demonstrate that loss of LIP-1 (dual specificity phosphatase) in fbf-1(ok91) single mutants leads to excess sperm production due to a delayed sperm-oocyte switch. This phenotype was dramatically rescued by depletion of MPK-1 (an ERK homolog). In contrast, loss of LIP-1 in fbf-2(q738) single mutants leads to a premature sperm-oocyte switch and loss of sperm. Notably, fbf-1 fbf-2; lip-1 triple mutants produce excess sperm. These results suggest that the MPK-1/ERK regulatory network, including FBF-1, FBF-2, and LIP-1, controls the number of sperm by regulating the timing of the sperm-oocyte switch in C. elegans. Copyright © 2017 Elsevier Inc. All rights reserved.

The influence of powdered coconut water (ACP-318®) in in vitro maturation of canine oocytes.

PubMed

Silva, A E F; Cavalcante, L F; Rodrigues, B A; Rodrigues, J L

2010-12-01

The objective of this study was to determine the influence of powdered coconut water (ACP-318(®)) diluted in high glucose (11.0 mM) TCM199 in the achievement of nuclear in vitro maturation (IVM) of canine oocytes. Cumulus oocyte complexes (COCs) (n = 632) were randomly allocated into three experimental groups named as group 1 (control group), group 2 (5% powdered coconut water) and group 3 (10% powdered coconut water). The percentage of meiotic resumption (MR) (GVBD to MII) was 39.1% (81/207), 50.2% (108/215) and 46.6% (98/210) for groups 1, 2 and 3 respectively (p < 0.05). There were no differences in MR rates among groups 2 and 3. The medium with ACP-318(®) slightly enhanced the nuclear maturation of canine oocytes when a comparison was established with rates of maturation exhibited by oocytes in the experimental group 1 without ACP-318(®) (p < 0.05). The results suggest that oocytes' nuclear morphology integrity and meiosis achievement were positively influenced when exposed to high glucose TCM199 supplemented with 5% powdered coconut water. Further investigation must be performed for a better understanding of powdered coconut water influence in cellular events during IVM of dog oocytes. © 2009 Blackwell Verlag GmbH.

Vesicular transport protein Arf6 modulates cytoskeleton dynamics for polar body extrusion in mouse oocyte meiosis.

PubMed

Duan, Xing; Zhang, Hao-Lin; Pan, Meng-Hao; Zhang, Yu; Sun, Shao-Chen

2018-02-01

Arf6 (ADP-ribosylation factor 6) is known to play important roles in membrane dynamics through the regulation of actin filament reorganization for multiple cellular processes such as cytokinesis, phagocytosis, cell migration and tumor cell invasion. However, the functions of Arf6 in mammalian oocyte meiosis have not been clarified. In present study we showed that Arf6 expressed in mouse oocytes and was mainly distributed around the spindle during meiosis. Depletion of Arf6 by morpholino microinjection caused oocytes failing to extrude first polar body. Further analysis indicated that Arf6 knock down caused the aberrant actin distribution, which further induced the failure of meiotic spindle movement. And the loss of oocyte polarity also confirmed this. The regulation of Arf6 on actin filaments in mouse oocytes might be due to its effects on the phosphorylation level of cofilin and the expression of Arp2/3 complex. Moreover, we found that the decrease of Arf6 caused the disruption of spindle formation, indicating the multiple roles of Arf6 on cytoskeleton dynamics in meiosis. In summary, our results indicated that Arf6 was involved in mouse oocyte meiosis through its functional roles in actin-mediated spindle movement and spindle organization. Copyright © 2017 Elsevier B.V. All rights reserved.

Histone H2AFX Links Meiotic Chromosome Asynapsis to Prophase I Oocyte Loss in Mammals

PubMed Central

Cloutier, Jeffrey M.; Mahadevaiah, Shantha K.; ElInati, Elias; Nussenzweig, André; Tóth, Attila; Turner, James M. A.

2015-01-01

Chromosome abnormalities are common in the human population, causing germ cell loss at meiotic prophase I and infertility. The mechanisms driving this loss are unknown, but persistent meiotic DNA damage and asynapsis may be triggers. Here we investigate the contribution of these lesions to oocyte elimination in mice with chromosome abnormalities, e.g. Turner syndrome (XO) and translocations. We show that asynapsed chromosomes trigger oocyte elimination at diplonema, which is linked to the presence of phosphorylated H2AFX (γH2AFX). We find that DNA double-strand break (DSB) foci disappear on asynapsed chromosomes during pachynema, excluding persistent DNA damage as a likely cause, and demonstrating the existence in mammalian oocytes of a repair pathway for asynapsis-associated DNA DSBs. Importantly, deletion or point mutation of H2afx restores oocyte numbers in XO females to wild type (XX) levels. Unexpectedly, we find that asynapsed supernumerary chromosomes do not elicit prophase I loss, despite being enriched for γH2AFX and other checkpoint proteins. These results suggest that oocyte loss cannot be explained simply by asynapsis checkpoint models, but is related to the gene content of asynapsed chromosomes. A similar mechanistic basis for oocyte loss may operate in humans with chromosome abnormalities. PMID:26509888

Liposome-encapsulated diacyl glycerol and inositol triphosphate-induced delayed oocyte activation and poor development of parthenotes.

PubMed

Nair, Ramya; Manikkath, Jyothsna; Hegde, Aswathi R; Mutalik, Srinivas; Kalthur, Guruprasad; Adiga, Satish Kumar

2017-09-01

To explore the ability of diacyl glycerol (DAG) and inositol triphosphate (IP3), two major secondary messengers in the calcium signaling pathway, in activating oocytes. Oocyte cumulus complex obtained from superovulated Swiss albino mice were incubated in M16 medium with liposome-encapsulated 1,2-Dipalmitoyl-sn-glycerol (LEDAG) and/or IP3 for 3 h. Strontium chloride was used as positive control. The activation potential, ploidy status, and blastocyst rate was calculated. Both DAG and IP3, individually, induced activation in ~98% of oocytes, which was significantly higher (p<0.01) than activation induced by strontium chloride (60%). Delayed pronucleus formation and a higher percentage of diploid parthenotes was observed in oocytes activated with LEDAG and/or IP3. However, these embryos failed to progress beyond the 6-8-cell stage. Only when the medium was supplemented with LEDAG (5 μg/mL) and IP3 (10 μg/mL) could activated oocytes progress till the blastocyst stage (5.26%), which was lower than the blastocyst rate in the positive controls (13.91%). The results of the present study indicate that DAG and IP3 can induce delayed oocyte activation and poor development of parthenotes in vitro.

Oocyte activation and phospholipase C zeta (PLCζ): diagnostic and therapeutic implications for assisted reproductive technology

PubMed Central

2012-01-01

Infertility affects one in seven couples globally and has recently been classified as a disease by the World Health Organisation (WHO). While in-vitro fertilisation (IVF) offers effective treatment for many infertile couples, cases exhibiting severe male infertility (19–57%) often remain difficult, if not impossible to treat. In such cases, intracytoplasmic sperm injection (ICSI), a technique in which a single sperm is microinjected into the oocyte, is implemented. However, 1–5% of ICSI cycles still fail to fertilise, affecting over 1000 couples per year in the UK alone. Pregnancy and delivery rates for IVF and ICSI rarely exceed 30% and 23% respectively. It is therefore imperative that Assisted Reproductive Technology (ART) protocols are constantly modified by associated research programmes, in order to provide patients with the best chances of conception. Prior to fertilisation, mature oocytes are arrested in the metaphase stage of the second meiotic division (MII), which must be alleviated to allow the cell cycle, and subsequent embryogenesis, to proceed. Alleviation occurs through a series of concurrent events, collectively termed ‘oocyte activation’. In mammals, oocytes are activated by a series of intracellular calcium (Ca2+) oscillations following gamete fusion. Recent evidence implicates a sperm-specific phospholipase C, PLCzeta (PLCζ), introduced into the oocyte following membrane fusion as the factor responsible. This review summarises our current understanding of oocyte activation failure in human males, and describes recent advances in our knowledge linking certain cases of male infertility with defects in PLCζ expression and activity. Systematic literature searches were performed using PubMed and the ISI-Web of Knowledge. Databases compiled by the United Nations and World Health Organisation databases (UNWHO), and the Human Fertilization and Embryology Authority (HFEA) were also scrutinised. It is clear that PLCζ plays a fundamental role in the activation of mammalian oocytes, and that genetic, molecular, or biochemical perturbation of this key enzyme is strongly linked to human infertility where oocyte activation is deficient. Consequently, there is significant scope for our understanding of PLCζ to be translated to the ART clinic, both as a novel therapeutic agent with which to rescue oocyte activation deficiency (OAD), or as a prognostic/diagnostic biomarker of oocyte activation ability in target sperm samples. PMID:22591604

Novel mutations in PATL2 cause female infertility with oocyte germinal vesicle arrest.

PubMed

Huang, Lingli; Tong, Xianhong; Wang, Fengsong; Luo, Lihua; Jin, Rentao; Fu, Yingyun; Zhou, Guixiang; Li, Daojing; Song, Gaojie; Liu, Yusheng; Zhu, Fuxi

2018-06-01

Do PATL2 mutations account for female infertility with oocyte germinal vesicle (GV) arrest? Four of nine independent families with oocyte GV arrest were identified with biallelic PATL2 mutations, suggesting that these mutations may be responsible for oocyte maturation arrest in primary infertile women. Recently, two independent studies have demonstrated that infertility in some women with oocyte maturation arrest at the GV stage was caused by biallelic mutations in PATL2. PATL2 encodes protein PAT1 homolog 2, an RNA-binding protein that may act as a translational repressor. In this study, nine unrelated primary infertile females presenting with oocyte GV arrest were recruited during the treatment of early rescue ICSI or ICSI from January 2013 to December 2016. Genomic DNA was isolated from blood samples obtained from all nine affected individuals and all of their available family members. All the coding regions of PATL2 were sequenced by Sanger sequencing. The pathogenicity of the identified variants and their possible effects on the protein were evaluated in silico. Five novel point mutations and one recurrent splicing mutation in PATL2 were identified in four of nine (44.4%) unrelated patients. We found a consanguineous family with a homozygous missense mutation in two affected sisters, and their fertile brother. There were no clear phenotypic differences in oocytes between the patient with the homozygous missense mutation, patients with nonsense mutations and undiagnosed patients. n/a. The function of PATL2 remains largely unknown. Both the exact pathogenic mechanism(s) of mutated PATL2 causing human oocyte maturation arrest and the strategies to overcome this condition should be further investigated in the future. According to our data, mutations in PATL2 account for 44.4% of the individuals with oocyte GV arrest. Our study further confirms that PATL2 is required for human oocyte maturation and female fertility, which indicates a potential prognostic value of testing for PATL2 mutations in primary infertile women with oocyte maturation arrest. Natural Science Foundation of Anhui Province (1808085MH241), National Natural Science Foundation of China (81401251 and 81370757) and Central Guided Local Development of Science and Technology Special Fund (2016080802D114) supported this study. None of the authors have any competing interests.

Distribution and viability of spermatozoa in the canine female genital tract during post-ovulatory oocyte maturation

PubMed Central

2012-01-01

Background Unlike other domestic mammals, in which metaphase-II oocytes are ovulated, canine ovulation is characterized by the release of primary oocytes, which may take 12 to up to 36 hours. Further 60 hours are needed for maturation to secondary oocytes which then remain fertile for about 48 hours. Oestrus takes 7 to 10 days on average and may start as early as a week before ovulation. This together with the prolonged process of post-ovulatory oocyte maturation requires an according longevity of spermatozoa in the female genital tract in order to provide a population of fertile sperm when oocytes have matured to fertilizability. Therefore the distribution and viability of spermatozoa in the bitch genital tract was examined during post-ovulatory oocyte maturation. Methods Thirteen beagle bitches were inseminated on the day of sonographically verified ovulation with pooled semen of two beagle dogs containing one billion progressively motile spermatozoa. Ovariohysterectomy was performed two days later (group 1, n = 6) and four days later (group 2, n = 7). The oviduct and uterine horn of one side were flushed separately and the flushing’s were checked for the presence of gametes. The oviducts including the utero-tubal junction and the uterine horns, both the flushed and unflushed, were histologically examined for sperm distribution. Results The total number of spermatozoa recovered by flushing was low and evaluation of viability was limited. Prophase-I oocytes were collected from oviduct flushing in group 1, whereas unfertilized metaphase-II oocytes were detected in group 2. From day 2 to day 4 after ovulation a significant decrease in the percentage of glands containing sperm (P<0.05) and a marked reduction of the mean sperm number in uterine horn glands were observed. A concomitant diminution of spermatozoa was indicated in the utero-tubal junction accompanied by a slight increase in sperm numbers in the mid oviduct. Conclusions Oocyte maturation to metaphase-II stage is accompanied by a continuous sperm detachment and elimination in the uterine horns. Entrance of spermatozoa into the caudal oviduct seems to be steadily controlled by the utero-tubal junction thus providing a selected sperm population to be shifted towards the site of fertilization when oocyte maturation is completed. PMID:22932162

Preliminary observations on polar body extrusion and pronuclear formation in human oocytes using time-lapse video cinematography.

PubMed

Payne, D; Flaherty, S P; Barry, M F; Matthews, C D

1997-03-01

In this study, we have used time-lapse video cinematography to study fertilization in 50 human oocytes that had undergone intracytoplasmic sperm injection (ICSI). Time-lapse recording commenced shortly after ICSI and proceeded for 17-20 h. Oocytes were cultured in an environmental chamber which was maintained under standard culture conditions. Overall, 38 oocytes (76%) were fertilized normally, and the fertilization rate and embryo quality were not significantly different from 487 sibling oocytes cultured in a conventional incubator. Normal fertilization followed a defined course of events, although the timing of these events varied markedly between oocytes. In 35 of the 38 fertilized oocytes (92%), there were circular waves of granulation within the ooplasm which had a periodicity of 20-53 min. The sperm head decondensed during this granulation phase. The second polar body was then extruded, and this was followed by the central formation of the male pronucleus. The female pronucleus formed in the cytoplasm adjacent to the second polar body at the same time as, or slightly after, the male pronucleus, and was subsequently drawn towards the male pronucleus until the two abutted. Both pronuclei then increased in size, the nucleoli moved around within the pronuclei and some nucleoli coalesced. During pronuclear growth, the organelles contracted from the cortex towards the centre of the oocyte, leaving a clear cortical zone. The oocyte decreased in diameter from 112 to 106 microm (P < 0.0001) during the course of the observation period. The female pronucleus was significantly smaller in diameter than the male pronucleus (24.1 and 22.4 microm respectively, P = 0.008) and contained fewer nucleoli (4.2 and 7.0 respectively, P < 0.0001). After time-lapse recording, oocytes were cultured for 48 h prior to embryo transfer or cryopreservation. Embryo quality was related to fertilization events and periodicity of the cytoplasmic wave, and it was found that good quality embryos arose from oocytes that had more uniform timing from injection to pronuclear abuttal and tended to have a longer cytoplasmic wave. In conclusion, we have shown that time-lapse video cinematography is an excellent tool for studying fertilization and early embryo development, and have demonstrated that human fertilization comprises numerous complex dynamic events.

Factors affecting the efficiency of foal production in a commercial oocyte transfer program.

PubMed

Riera, Fernando L; Roldán, Jaime E; Gomez, José; Hinrichs, Katrin

2016-04-01

Transfer of donor oocytes to the oviducts of inseminated recipient mares (oocyte transfer, OT) presents a valuable method for production of foals from otherwise infertile mares. Little information is available, however, on factors affecting success of OT in a clinical setting. We report the findings over three breeding seasons in a commercial OT program developed at an equine embryo transfer center in Argentina. Overall, 25 mares were enrolled, and 197 follicle aspiration procedures were performed. The average mare age was 23 years. Follicle aspiration was performed with a needle placed through the flank; the oocyte recovery rate per follicle aspirated was 149 of 227 (66%). Induction of donor ovulation with deslorelin + hCG resulted in a significantly higher oocyte recovery rate than did induction with deslorelin alone (75% vs. 58%). There was no significant effect of mare age (17-20, 21-24, or 25-27 years) on oocyte recovery rate. Twelve oocytes were degenerating or lost during handling; transfer of the remaining 137 oocytes resulted in 42 pregnancies (31%) at 14 days. Of these, 32 (23% per transfer) went on to produce a foal or ongoing pregnancy. Transfer of oocytes recovered with a compact cumulus, without donor follicle induction, or less than 20 hours after induction was associated with a significantly reduced pregnancy rate (1/16, 6%), as was use of noncycling, hormone-treated recipients (2/22, 9%). To evaluate management factors affecting pregnancy rate, noncycling, hormone-treated recipients were disregarded, and only procedures using mature (expanded cumulus) oocytes recovered and transferred on the standard schedule (n = 99) were included. Mare age did not significantly affect rates of pregnancy or pregnancy loss. Similar pregnancy rates were obtained using recipients inseminated from 1 to 27 hours before transfer. Counterintuitively, insemination of recipients immediately (1-2 hours) after aspiration of the recipient follicle was associated with a high pregnancy rate (10/12, 83%). There was no significant effect on pregnancy rate of donor induction agent, the time the oocyte was in culture (2-20 hours) before transfer, time from recipient insemination to transfer, or total time from donor induction to transfer (32-45 hours). These findings establish that OT is robust, in that it is effective over a wide variation in timing of the different components involved, and can be successfully developed in a private embryo transfer practice. Copyright © 2016 Elsevier Inc. All rights reserved.

Oocyte activation and phospholipase C zeta (PLCζ): diagnostic and therapeutic implications for assisted reproductive technology.

PubMed

Ramadan, Walaa M; Kashir, Junaid; Jones, Celine; Coward, Kevin

2012-07-09

Infertility affects one in seven couples globally and has recently been classified as a disease by the World Health Organisation (WHO). While in-vitro fertilisation (IVF) offers effective treatment for many infertile couples, cases exhibiting severe male infertility (19-57%) often remain difficult, if not impossible to treat. In such cases, intracytoplasmic sperm injection (ICSI), a technique in which a single sperm is microinjected into the oocyte, is implemented. However, 1-5% of ICSI cycles still fail to fertilise, affecting over 1000 couples per year in the UK alone. Pregnancy and delivery rates for IVF and ICSI rarely exceed 30% and 23% respectively. It is therefore imperative that Assisted Reproductive Technology (ART) protocols are constantly modified by associated research programmes, in order to provide patients with the best chances of conception. Prior to fertilisation, mature oocytes are arrested in the metaphase stage of the second meiotic division (MII), which must be alleviated to allow the cell cycle, and subsequent embryogenesis, to proceed. Alleviation occurs through a series of concurrent events, collectively termed 'oocyte activation'. In mammals, oocytes are activated by a series of intracellular calcium (Ca2+) oscillations following gamete fusion. Recent evidence implicates a sperm-specific phospholipase C, PLCzeta (PLCζ), introduced into the oocyte following membrane fusion as the factor responsible. This review summarises our current understanding of oocyte activation failure in human males, and describes recent advances in our knowledge linking certain cases of male infertility with defects in PLCζ expression and activity. Systematic literature searches were performed using PubMed and the ISI-Web of Knowledge. Databases compiled by the United Nations and World Health Organisation databases (UNWHO), and the Human Fertilization and Embryology Authority (HFEA) were also scrutinised. It is clear that PLCζ plays a fundamental role in the activation of mammalian oocytes, and that genetic, molecular, or biochemical perturbation of this key enzyme is strongly linked to human infertility where oocyte activation is deficient. Consequently, there is significant scope for our understanding of PLCζ to be translated to the ART clinic, both as a novel therapeutic agent with which to rescue oocyte activation deficiency (OAD), or as a prognostic/diagnostic biomarker of oocyte activation ability in target sperm samples.

Human oocyte calcium analysis predicts the response to assisted oocyte activation in patients experiencing fertilization failure after ICSI.

PubMed

Ferrer-Buitrago, M; Dhaenens, L; Lu, Y; Bonte, D; Vanden Meerschaut, F; De Sutter, P; Leybaert, L; Heindryckx, B

2018-01-10

Can human oocyte calcium analysis predict fertilization success after assisted oocyte activation (AOA) in patients experiencing fertilization failure after ICSI? ICSI-AOA restores the fertilization rate only in patients displaying abnormal Ca2+ oscillations during human oocyte activation. Patients capable of activating mouse oocytes and who showed abnormal Ca2+ profiles after mouse oocyte Ca2+ analysis (M-OCA), have variable responses to ICSI-AOA. It remains unsettled whether human oocyte Ca2+ analysis (H-OCA) would yield an improved accuracy to predict fertilization success after ICSI-AOA. Sperm activation potential was first evaluated by MOAT. Subsequently, Ca2+ oscillatory patterns were determined with sperm from patients showing moderate to normal activation potential based on the capacity of human sperm to generate Ca2+ responses upon microinjection in mouse and human oocytes. Altogether, this study includes a total of 255 mouse and 122 human oocytes. M-OCA was performed with 16 different sperm samples before undergoing ICSI-AOA treatment. H-OCA was performed for 11 patients who finally underwent ICSI-AOA treatment. The diagnostic accuracy to predict fertilization success was calculated based on the response to ICSI-AOA. Patients experiencing low or total failed fertilization after conventional ICSI were included in the study. All participants showed moderate to high rates of activation after MOAT. Metaphase II (MII) oocytes from B6D2F1 mice were used for M-OCA. Control fertile sperm samples were used to obtain a reference Ca2+ oscillation profile elicited in human oocytes. Donated human oocytes, non-suitable for IVF treatments, were collected and vitrified at MII stage for further analysis by H-OCA. M-OCA and H-OCA predicted the response to ICSI-AOA in 8 out of 11 (73%) patients. Compared to M-OCA, H-OCA detected the presence of sperm activation deficiencies with greater sensitivity (75 vs 100%, respectively). ICSI-AOA never showed benefit to overcome fertilization failure in patients showing normal capacity to generate Ca2+ oscillations in H-OCA and was likely to be beneficial in cases displaying abnormal H-OCA Ca2+ oscillations patterns. The scarce availability of human oocytes donated for research purposes is a limiting factor to perform H-OCA. Ca2+ imaging requires specific equipment to monitor fluorescence changes over time. H-OCA is a sensitive test to diagnose gamete-linked fertilization failure. H-OCA allows treatment counseling for couples experiencing ICSI failures to either undergo ICSI-AOA or to participate in gamete donation programs. The present data provide an important template of the Ca2+ signature observed during human fertilization in cases with normal, low and failed fertilization after conventional ICSI. This work was supported by the Flemish fund for scientific research (FWO-Vlaanderen, G060615N). The authors have no conflict of interest to declare. © The Author(s) 2018. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

Oocyte vitrification as an efficient option for elective fertility preservation.

PubMed

Cobo, Ana; García-Velasco, Juan A; Coello, Aila; Domingo, Javier; Pellicer, Antonio; Remohí, José

2016-03-01

To provide a detailed description of the current oocyte vitrification status as a means of elective fertility preservation (EFP). Retrospective observational multicenter study. Private university-affiliated center. A total of 1,468 women who underwent EFP because of age or having associated a medical condition other than cancer (January 2007 to April 2015). None. Survival and cumulative live birth rate (CLBR) per consumed oocyte. Mean age was higher with EFP due to age versus having an associated medical reason (37.7 y [95% confidence interval (CI) 36.5-37.9] vs. 35.7 y [95% CI 34.9-36.3]). In total, 137 patients (9.3%) returned to use their oocytes. Overall survival rate was 85.2% (95% CI 83.2-87.2). Live birth rate per patient was higher in women ≤35 years old than ≥36 years old (50% [95% CI 32.7-67.3] vs. 22.9% [95% CI 14.9-30.9]). CLBR was higher and increased faster in younger women. The gain in CLBR was sharp from 5 (15.4%, 95% CI -4.2 to 35.0) to 8 oocytes (40.8%, 95% CI 13.2-68.4), with an 8.4% gain per additional oocyte, in the ≤35-year-old group. The increase was slower with 10-15 oocytes, reaching a plateau CLBR of 85.2%. A milder increase (4.9% gain) was observed in the ≥36-year-old group (from 5.1% [95% CI -0.6 to 10.7] to 19.9% [95% CI 8.7-31.1] when 5-8 oocytes were consumed), reaching the plateau with 11 oocytes (CLBR 35.6%). Forty babies were born. At least 8-10 metaphase II oocytes are necessary to achieve reasonable success. Numbers should be individualized in women >36 years old. We suggest encouraging women who are motivated exclusively by a desire to postpone childbearing because of age, to come at younger ages to increase success possibilities. Copyright © 2016 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Production of blastocysts following in vitro maturation and fertilization of dromedary camel oocytes vitrified at the germinal vesicle stage.

PubMed

Fathi, Mohamed; Moawad, Adel R; Badr, Magdy R

2018-01-01

Cryopreservation of oocytes would serve as an alternative to overcome the limited availability of dromedary camel oocytes and facilitate improvements in IVP techniques in this species. Our goal was to develop a protocol for the vitrification of camel oocytes at the germinal vesicle (GV) stage using different cryoprotectant combinations: 20% EG and 20% DMSO (VS1), 25% EG plus 25% DMSO (VS2) or 25% EG and 25% glycerol (VS3) and various cryo-carriers; straws or open pulled-straw (OPS) or solid surface vitrification (SSV); and Cryotop. Viable oocytes were cultured in vitro for 30 h. Matured oocytes were fertilized with epididymal spermatozoa and then cultured in vitro in modified KSOMaa medium for 7 days. Survival and nuclear maturation rates were significantly lower (P ≤ 0.05) in oocytes exposed to VS3 (44.8% and 34.0%, respectively) than those exposed to VS1 (68.2% and 48.0%, respectively) and VS2 (79.3% and 56.9%, respectively). Although recovery rates were significantly lower (P ≤ 0.05) in SSV and Cryotop vitrified oocytes (66.9% to 71.1%) than those vitrified by straws with VS1 or VS2 solutions (86.3% to 91.0%), survival rates were higher in the SSV and Cryotop groups (90.7% to 94.8%) than in the straw and OPS groups (68.2% to 86.5%). Among vitrified groups, maturation and fertilization rates were the highest in the Cryotop-VS2 group (51.8% and 39.2%, respectively). These values were comparable to those seen in the controls (59.2% and 44.6%, respectively). Cleavage (22.5% to 27.9%), morula (13.2% to 14.5%), and blastocyst (6.4% to 8.5%) rates were significantly higher (P ≤ 0.05) in SSV and Cryotop groups than in straws. No significant differences were observed in these parameters between the Cryotop and control groups. We report for the first time that dromedary oocytes vitrified at the GV-stage have the ability to be matured, fertilized and subsequently develop in vitro to produce blastocysts at frequencies comparable to those obtained using fresh oocytes.

Oocyte Polarization Is Coupled to the Chromosomal Bouquet, a Conserved Polarized Nuclear Configuration in Meiosis

PubMed Central

Elkouby, Yaniv M.; Jamieson-Lucy, Allison; Mullins, Mary C.

2016-01-01

The source of symmetry breaking in vertebrate oocytes is unknown. Animal—vegetal oocyte polarity is established by the Balbiani body (Bb), a conserved structure found in all animals examined that contains an aggregate of specific mRNAs, proteins, and organelles. The Bb specifies the oocyte vegetal pole, which is key to forming the embryonic body axes as well as the germline in most vertebrates. How Bb formation is regulated and how its asymmetric position is established are unknown. Using quantitative image analysis, we trace oocyte symmetry breaking in zebrafish to a nuclear asymmetry at the onset of meiosis called the chromosomal bouquet. The bouquet is a universal feature of meiosis where all telomeres cluster to one pole on the nuclear envelope, facilitating chromosomal pairing and meiotic recombination. We show that Bb precursor components first localize with the centrosome to the cytoplasm adjacent to the telomere cluster of the bouquet. They then aggregate around the centrosome in a specialized nuclear cleft that we identified, assembling the early Bb. We show that the bouquet nuclear events and the cytoplasmic Bb precursor localization are mechanistically coordinated by microtubules. Thus the animal—vegetal axis of the oocyte is aligned to the nuclear axis of the bouquet. We further show that the symmetry breaking events lay upstream to the only known regulator of Bb formation, the Bucky ball protein. Our findings link two universal features of oogenesis, the Bb and the chromosomal bouquet, to oocyte polarization. We propose that a meiotic—vegetal center couples meiosis and oocyte patterning. Our findings reveal a novel mode of cellular polarization in meiotic cells whereby cellular and nuclear polarity are aligned. We further reveal that in zygotene nests, intercellular cytoplasmic bridges remain between oocytes and that the position of the cytoplasmic bridge coincides with the location of the centrosome meiotic—vegetal organizing center. These results suggest that centrosome positioning is set by the last mitotic oogonial division plane. Thus, oocytes are polarized in two steps: first, mitotic divisions preset the centrosome with no obvious polarization yet, then the meiotic—vegetal center forms at zygotene bouquet stages, when symmetry is, in effect, broken. PMID:26741740

Effects of recipient oocyte age and interval from fusion to activation on development of buffalo (Bubalus bubalis) nuclear transfer embryos derived from fetal fibroblasts.

PubMed

Lu, F; Jiang, J; Li, N; Zhang, S; Sun, H; Luo, C; Wei, Y; Shi, D

2011-09-15

The objective was to investigate the effect of recipient oocyte age and the interval from activation to fusion on developmental competence of buffalo nuclear transfer (NT) embryos. Buffalo oocytes matured in vitro for 22 h were enucleated by micromanipulation under the spindle view system, and a fetal fibroblast (pretreated with 0.1 μg/mL aphidicolin for 24 h, followed by culture for 48 h in 0.5% fetal bovine serum) was introduced into the enucleated oocyte, followed by electrofusion. Both oocytes and NT embryos were activated by exposure to 5 μM ionomycin for 5 min, followed by culture in 2 mM 6-dimethyl-aminopurine for 3 h. When oocytes matured in vitro for 28, 29, 30, 31, or 32 h were activated, more oocytes matured in vitro for 30 h developed into blastocysts in comparison with oocytes matured in vitro for 32 h (31.3 vs 19.9%, P < 0.05). When electrofusion was induced 27 h after the onset of oocyte maturation, the cleavage rate (78.0%) was higher than that of electrofusion induced at 28 h (67.2%, P < 0.05), and the blastocyst yield (18.1%) was higher (P < 0.05) than that of electrofusion induced at 25 or 26 h (7.4 and 8.5%, respectively). A higher proportion of NT embryos activated at 3 h after electrofusion developed to the blastocyst stage (18.6%) in comparison with NT embryos activated at 1 h (6.0%), 2 h (8.3%), or 4 h (10.6%) after fusion (P < 0.05). No recipient was pregnant 60 d after transfer of blastocysts developed from NT embryos activated at 1 h (0/8), 2 h (0/10), or 4 h (0/9) after fusion. However, 3 of 16 recipients were pregnant following transfer of blastocysts developed from the NT embryos activated at 3 h after fusion, and two of these recipients maintained pregnancy to term. We concluded that the developmental potential of buffalo NT embryos was related to recipient oocyte age and the interval from fusion to activation. Copyright © 2011 Elsevier Inc. All rights reserved.

Superovulation Using the Combined Administration of Inhibin Antiserum and Equine Chorionic Gonadotropin Increases the Number of Ovulated Oocytes in C57BL/6 Female Mice

PubMed Central

Takeo, Toru; Nakagata, Naomi

2015-01-01

Superovulation is a reproductive technique generally used to produce genetically engineered mice. Superovulation in mice involves the administration of equine chorionic gonadotropin (eCG) to promote follicle growth and then that of human chorionic gonadotropin (hCG) to induce ovulation. Previously, some published studies reported that inhibin antiserum (IAS) increased the number of ovulated oocytes in ddY and wild-derived strains of mice. However, the effect of IAS on the C57BL/6 strain, which is the most widely used inbred strain for the production of genetically engineered mice, has not been investigated. In addition, the combined effect of IAS and eCG (IASe) on the number of ovulated oocytes in superovulation treatment has not been examined. In this study, we examined the effect of IAS and eCG on the number of ovulated oocytes in immature female mice of the C57BL/6 strain in superovulation treatment. Furthermore, we evaluated the quality of obtained oocytes produced by superovulation using IASe by in vitro fertilization (IVF) with sperm from C57BL/6 or genetically engineered mice. The developmental ability of fresh or cryopreserved embryos was examined by embryo transfer. The administration of IAS or eCG had a similar effect on the number of ovulated oocytes in C57BL/6 female mice. The number of ovulated oocytes increased to about 3-fold by the administration of IASe than by the administration of IAS or eCG alone. Oocytes derived from superovulation using IASe normally developed into 2-cell embryos by IVF using sperm from C57BL/6 mice. Fresh or cryopreserved 2-cell embryos produced by IVF between oocytes of C57BL/6 mice and sperm from genetically engineered mice normally developed into live pups following embryo transfer. In summary, a novel technique of superovulation using IASe is extremely useful for producing a great number of oocytes and offspring from genetically engineered mice. PMID:26024317

The pea aphid uses a version of the terminal system during oviparous, but not viviparous, development

PubMed Central

2013-01-01

Background In most species of aphid, female nymphs develop into either sexual or asexual adults depending on the length of the photoperiod to which their mothers were exposed. The progeny of these sexual and asexual females, in turn, develop in dramatically different ways. The fertilized oocytes of sexual females begin embryogenesis after being deposited on leaves (oviparous development) while the oocytes of asexual females complete embryogenesis within the mother (viviparous development). Compared with oviparous development, viviparous development involves a smaller transient oocyte surrounded by fewer somatic epithelial cells and a smaller early embryo that comprises fewer cells. To investigate whether patterning mechanisms differ between the earliest stages of the oviparous and viviparous modes of pea aphid development, we examined the expression of pea aphid orthologs of genes known to specify embryonic termini in other insects. Results Here we show that pea aphid oviparous ovaries express torso-like in somatic posterior follicle cells and activate ERK MAP kinase at the posterior of the oocyte. In addition to suggesting that some posterior features of the terminal system are evolutionarily conserved, our detection of activated ERK in the oocyte, rather than in the embryo, suggests that pea aphids may transduce the terminal signal using a mechanism distinct from the one used in Drosophila. In contrast with oviparous development, the pea aphid version of the terminal system does not appear to be used during viviparous development, since we did not detect expression of torso-like in the somatic epithelial cells that surround either the oocyte or the blastoderm embryo and we did not observe restricted activated ERK in the oocyte. Conclusions We suggest that while oviparous oocytes and embryos may specify posterior fate through an aphid terminal system, viviparous oocytes and embryos employ a different mechanism, perhaps one that does not rely on an interaction between the oocyte and surrounding somatic cells. Together, these observations provide a striking example of a difference in the fundamental events of early development that is both environmentally induced and encoded by the same genome. PMID:23552511

Effects of Crocin Supplementation during In Vitro Maturation of Mouse Oocytes on Glutathione Synthesis and Cytoplasmic Maturation

PubMed Central

Mokhber Maleki, Elham; Eimani, Hussein; Bigdeli, Mohammad Reza; Golkar Narenji, Afsane; Abedi, Reyhane

2016-01-01

Background Crocin is an active ingredient of saffron (Crocus sativus L.) and its antioxidant properties have been previously investigated. This carotenoid scavenges free radicals and stimulates glutathione (GSH) synthesis; consequently, it may protect cells against oxidative stress. The aim of this research is to protect oocytes from oxidative stress by the addition of a natural source antioxidant. Materials and Methods In the present in vitro experimental study, we collected cumulus oocyte complexes (COCs) from mouse ovaries of euthanized, 6-8 week-old female Naval Medical Research Institute (NMRI) mice. Oocytes were subjected to in vitro maturation (IVM) in the presence of either crocin (5 or 10 μg/ml), 5 mM buthionine-[S-R]- sulfoximine (BSO), or the combination of crocin plus BSO. Oocytes that matured in vitro in a medium without crocin or BSO supplements were considered as controls. Following 16-18 hours of IVM, matured oocytes (n=631) were fertilized by capacitated sperm from NMRI male mice, and cultured in vitro for up to 96 hours to assess preimplantation embryonic development. The levels of GSH in metaphase II (MII) oocytes after IVM (n=240) were also assessed by the 5, 5-dithio-bis (2-nitrobenzoic acid) (DTNB)-GSH reductase recycling assay. Results Supplementation of IVM media with 10 µg/ml crocin significantly (P<0.05) increased nuclear maturation, preimplantation development and GSH concentrations compared with the control group. Maturation of oocytes in IVM medium supplemented with BSO alone or the combination of 5 µg/ml crocin and BSO drastically decreased GSH concentrations and subsequently resulted in low rates of maturation, fertilization and blastocyst development. However, the combination of 10 µg/ml crocin with 5 mM BSO increased the level of nuclear maturation which was comparable to the control group. Conclusion Supplementation of IVM media with crocin can improve nuclear maturation rates and subsequent developmental potential of mouse oocytes. This may occur by its beneficial effect in increasing GSH concentrations in MII oocytes. PMID:27123201

Effect of recombinant bovine somatotropin (rbST) on cytoplasmic maturation of bovine oocytes and their developmental competence in vitro.

PubMed

Kuzmina, Tatjana I; Alm, Hannelore; Denisenko, Vitaly; Tuchscherer, Armin; Kanitz, Wilhelm; Torner, Helmut

2007-04-01

The objectives of this study were to evaluate the effects of recombinant bovine somatotropin (rbST) on the nuclear and cytoplasmic maturation of bovine oocytes and their further developmental competence to blastocysts in vitro. We analyzed the mitochondrial activity and concentration of intracellular stored calcium ([Ca(2+)](is)) in matured oocytes and the morphology and chromatin status of produced embryos after in vitro fertilization. Cumulus-oocyte complexes were incubated in TCM 199 containing 10% fetal calf serum (control medium 1: CM 1) or 10% estrus cow serum (control medium 2: CM 2). The culture medium of the treatment groups was modified by supplementation of the control medium with 10 ng/ml rbST (CM 1A and CM 2A), 10(6)/ml granulosa cells (CM 1B and CM 2B), or 10 ng/ml rbST plus 10(6)/ml granulosa cells (CM 1C and CM 2C). No differences were observed in the percentages of oocytes reaching metaphase II between the groups. However, the proportion of blastocysts was highest in treatment groups CM 1C and CM 2C (P<0.05). The type of serum did not alter the positive effect of rbST on the developmental competence of embryos. The fluorescence intensity of metabolically active mitochondria measured by intensity per oocyte (Em 570) after MitoTracker CMTM Ros Orange labeling was significantly increased in oocytes matured in the presence of 10 ng/ml rbST and granulosa cells (309.21 vs. 119.97 microA; P<0.01). In parallel, the concentration of [Ca(2+)](is) in oocytes, determined using fluorophore chlortetracycline, was significantly decreased (0.85 +/- 0.02 vs. 0.97 +/- 0.03 AU; P<0.05). Based on these results, we concluded that rbST, in interaction with granulosa cells stimulates the oxidative activity of ooplasmic mitochondria and decreases the content of [Ca(2+)](is) in oocytes. These facts support the hypothesis that somatotropin influences the developmental competence of bovine oocytes during maturation in vitro, and this effect can be modulated by granulosa cells.

Effects of Vitrification on Outcomes of In Vivo-Mature, In Vitro-Mature and Immature Human Oocytes.

PubMed

Song, Wen-Yan; Peng, Zhao-Feng; Chen, Xue-Mei; Jin, Hai-Xia; Yao, Gui-Dong; Shi, Sen-Lin; Yang, Hong-Yi; Zhang, Xiang-Yang; Sun, Ying-Pu

2016-01-01

To observe the effects of vitrification on spindle, zona pellucida, embryonic aneuploidy and DNA injury in in vivo-maruted, in vitro-mature and immature human oocytes. Between January 2009 and February 2015, 223 immature oocytes from 450 infertile patients, and 31 in vivo-mature oocytes from 3 infertile couples were collected. Of the 223 immature oocytes, 113 were used for in vitro culture before vitrification. Some oocytes were randomly divided into in vivo-mature group (group A, n = 15), in vitro-mature group (group B, n = 88) and immature group (group C, n = 85), and then the oocytes with spindle in these three groups after freezing-thawing were selected to use for Polscope imaging, embryonic aneuploidy screening and embryo development evaluation. Other oocytes were randomly divided into group A (n = 16), group B (n = 25) and group C (n = 25) for detecting DNA injury. After thawing, spindle occurrence rate, spindle Retardance value, and cleavage rate were significantly higher in groups A and B than in group C (all P < 0.05), but there were no statistical differences in fertility rate, high-quality embryo rate, blastulation rate and aneuploidy rate amongst the three groups (all P > 0.05). Zona pellucida density (ZPD) was significantly lower in group A than in groups B and C both before and after vitrification (all P < 0.05). ZPD was significantly higher after thawing than before vitrification (all P < 0.05), but zona pellucida thickness (ZPT) was not significantly changed in all the three groups (all P > 0.05). Rate of comet cells was significantly lower in group A than in groups B and C (all P < 0.01). Comet tail was significantly longer in group C than in groups B and A (all P < 0.05). In vivo- and in vitro-mature human oocytes are more suitable to vitrification than immature human oocytes. Spindle Retardance value has more predictive value for embryonic development potential than ZPD and ZPT. © 2016 The Author(s) Published by S. Karger AG, Basel.

Role of G-protein-coupled estrogen receptor (GPER/GPR30) in maintenance of meiotic arrest in fish oocytes.

PubMed

Thomas, Peter

2017-03-01

An essential role for GPER (formerly known as GPR30) in regulating mammalian reproduction has not been identified to date, although it has shown to be involved in the regulation a broad range of other estrogen-dependent functions. In contrast, an important reproductive role for GPER in the maintenance of oocyte meiotic arrest has been identified in teleost fishes, which is briefly reviewed here. Recent studies have clearly shown that ovarian follicle production of estradiol-17β (E 2 ) maintains meiotic arrest in several teleost species through activation of GPER coupled to a stimulatory G protein (G s ) on oocyte plasma membranes resulting in stimulation of cAMP production and maintenance of elevated cAMP levels. Studies with denuded zebrafish oocytes and with microinjection of GPER antisense oligonucleotides into oocytes have demonstrated the requirement for both ovarian follicle production of estrogens and expression of GPER on the oocyte surface for maintenance of meiotic arrest. This inhibitory action of E 2 on the resumption of meiosis is mimicked by the GPER-selective agonist G-1, by the GPER agonists and nuclear ER antagonists, ICI 182,780 and tamoxifen, and also by the xenoestrogen bisphenol-A (BPA) and related alkylphenols. GPER also maintains meiotic arrest of zebrafish oocytes through estrogen- and BPA-dependent GPER activation of epidermal growth factor receptor (EGFR) and mitogen-activated protein kinase (MAPK) signaling. Interestingly, progesterone receptor component 1 (PGRMC1) is also involved in estrogen maintenance of meiotic arrest through regulation of EGFR expression on the oocyte plasma membrane. The preovulatory surge in LH secretion induces the ovarian synthesis of progestin hormones that activate a membrane progestin receptor alpha (mPRα)/inhibitory G protein (Gi) pathway. It also increases ovarian synthesis of the catecholestrogen, 2-hydroxy-estradiol-17β (2-OHE 2 ) which inhibits the GPER/Gs/adenylyl cyclase pathway. Both of these LH actions cause declines in oocyte cAMP levels resulting in the resumption of meiosis. GPER is also present on murine oocytes but there are no reports of studies investigating its possible involvement in maintaining meiotic arrest in mammals. Copyright © 2016 Elsevier Ltd. All rights reserved.

Reprint of "Role of G protein-coupled estrogen receptor (GPER/GPR30) in maintenance of meiotic arrest in fish oocytes".

PubMed

Thomas, Peter

2018-02-01

An essential role for GPER (formerly known as GPR30) in regulating mammalian reproduction has not been identified to date, although it has shown to be involved in the regulation a broad range of other estrogen-dependent functions. In contrast, an important reproductive role for GPER in the maintenance of oocyte meiotic arrest has been identified in teleost fishes, which is briefly reviewed here. Recent studies have clearly shown that ovarian follicle production of estradiol-17β (E 2 ) maintains meiotic arrest in several teleost species through activation of GPER coupled to a stimulatory G protein (G s ) on oocyte plasma membranes, resulting in stimulation of cAMP production and maintenance of elevated cAMP levels. Studies with denuded zebrafish oocytes and with microinjection of GPER antisense oligonucleotides into oocytes have demonstrated the requirement for both ovarian follicle production of estrogens and expression of GPER on the oocyte surface for maintenance of meiotic arrest. This inhibitory action of E 2 on the resumption of meiosis is mimicked by the GPER-selective agonist G-1, by the GPER agonists and nuclear ER antagonists, ICI 182,780 and tamoxifen, and also by the xenoestrogen bisphenol-A (BPA) and related alkylphenols. GPER also maintains meiotic arrest of zebrafish oocytes through estrogen- and BPA-dependent GPER activation of epidermal growth factor receptor (EGFR) and mitogen-activated protein kinase (MAPK) signaling. Interestingly, progesterone receptor component 1 (PGRMC1) is also involved in estrogen maintenance of meiotic arrest through regulation of EGFR expression on the oocyte plasma membrane. The preovulatory surge in LH secretion induces the ovarian synthesis of progestin hormones that activate a membrane progestin receptor alpha (mPRα)/inhibitory G protein (Gi) pathway. It also increases ovarian synthesis of the catecholestrogen, 2-hydroxy-estradiol-17β (2-OHE 2 ) which inhibits the GPER/Gs/adenylyl cyclase pathway. Both of these LH actions cause declines in oocyte cAMP levels resulting in the resumption of meiosis. GPER is also present on murine oocytes but there are no reports of studies investigating its possible involvement in maintaining meiotic arrest in mammals. Copyright © 2017 Elsevier Ltd. All rights reserved.

[A prospective study to compare the efficiency of oocyte vitrification using closed or open devices].

PubMed

Sarandi, S; Herbemont, C; Sermondade, N; Benoit, A; Sonigo, C; Poncelet, C; Benard, J; Gronier, H; Boujenah, J; Grynberg, M; Sifer, C

2016-05-01

Oocyte vitrification using an open device is thought to be a source of microbiological and chemical contaminations that can be avoided using a closed device. The principal purpose of this study was to compare the two vitrification protocols: closed and open system. The secondary aim was to study the effects of the storage in the vapor phase of nitrogen (VPN) on oocytes vitrified using an open system and to compare it to those of a storage in liquid nitrogen (LN). Forty-four patients have been included in our study between November 2014 and May 2015. Two hundred and fourteen oocytes have been vitrified at germinal vesicle (GV), metaphase I (0PB) and metaphase II (1PB) stages. We vitrified 96 oocytes (59 GV/37 0PB) using a closed vitrification device and 118 oocytes (57 GV/31 0PB/30 1PB) using an open device. The vitrified oocytes were then stored either in LN or in VPN. The main outcome measures were the survival rate after warming (SR), meiosis resumption rate (MRR) and maturation rate (MR). The global post-thaw SR was significantly higher for oocytes vitrified using an open system (93.2%) compared to those vitrified using a closed one (64.5%; P<0.001). On the contrary, there was no significant difference in terms of global MRR and MR (82.1% vs. 87.5% and 60.7% vs. 61.2% using closed and open system respectively). The SR, MRR and the MR were not significantly different when vitrified oocytes were stored in VPN or LN (91.6, 83.8, 64.5% vs. 93.9, 89.8, 59.1% respectively). Taking into account the limits of our protocol, the open vitrification system remains the more efficient system. The use of sterile liquid nitrogen for oocyte vitrification and the subsequent storage in vapor phase of nitrogen could minimize the hypothetical risks of biological and chemical contaminations. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Evaluation of foal production following intracytoplasmic sperm injection and blastocyst culture of oocytes from ovaries collected immediately before euthanasia or after death of mares under field conditions.

PubMed

Hinrichs, Katrin; Choi, Young-Ho; Norris, Jody D; Love, Linda B; Bedford-Guaus, Sylvia J; Hartman, David L; Velez, Isabel C

2012-10-15

To evaluate the efficiency of foal production following intracytoplasmic sperm injection (ICSI) and blastocyst culture of oocytes from mares that died or were euthanized under field conditions. Prospective case series. 16 mares (age, 3 to 19 years) that died or were euthanized for various causes. Ovaries were collected immediately before euthanasia (n = 10) or after death (6). Ovaries were transported to the laboratory for oocyte recovery (15 mares), or oocytes were recovered at a remote location and shipped to the laboratory (1). Oocytes underwent ICSI, and presumptive zygotes were cultured for 7 to 10 days. Blastocysts were shipped to embryo transfer facilities for transcervical transfer to recipient mares. Ovaries were processed 30 minutes to 12 hours (mean ± SD, 4.6 ± 3.3 hours) after mares' deaths. A mean of 14.1 ± 8.6 oocytes/mare were cultured, and 110 of 225 (49%) matured. Twenty-one blastocysts developed after ICSI and were transferred to recipient mares. Thirteen pregnancies were established; 10 healthy foals were produced from 6 donor mares. The number of blastocysts produced per mare and number of live foals produced per mare were significantly correlated with the number of oocytes recovered. Foals were produced from mares after death or euthanasia under field conditions. Proportions of foals born overall (10 foals/16 mares) and mares from which ≥ 1 foal was produced (6/16) were greater than those reported following recovery and oviductal transfer of oocytes to inseminated recipients after death of donor mares under field conditions.

The optimal period of Ca-EDTA treatment for parthenogenetic activation of porcine oocytes during maturation culture

PubMed Central

MORITA, Yasuhiro; TANIGUCHI, Masayasu; TANIHARA, Fuminori; ITO, Aya; NAMULA, Zhao; DO, Lanh Thi Kim; TAKAGI, Mitsuhiro; TAKEMOTO, Tatsuya; OTOI, Takeshige

2016-01-01

The changes triggered by sperm-induced activation of oocytes, which are required for normal oocyte development, can be mediated by other agents, thereby inducing the parthenogenesis. In this study, we exposed porcine oocytes to 1 mM Ca-EDTA, a metal-ion chelator, at various intervals during 48 hr of in vitro maturation to determine the optimum period of Ca-EDTA treatment for parthenogenetic activation. When the oocytes were cultured with or without Ca-EDTA from 36 hr (post-12), 24 hr (post-24), 12 hr (post-36) and 0 hr (post-48) after the start of maturation culture, the blastocyst formation rates were significantly higher (P<0.05) in the post-24, post-36 and post-48 groups (3.3%, 4.0% and 2.6%, respectively) than those in the control group without treatment (0%). Furthermore, when the oocytes were cultured with Ca-EDTA for 0 hr (control), 12 hr (pre-12), 24 hr (pre-24), 36 hr (pre-36) and 48 hr (pre-48) from the start of maturation culture, the oocytes formed blastocysts only in the pre-36 and pre-48 groups (0.4% or 0.8%, respectively). Pronuclei (<66.7%) were observed only when the periods of Ca-EDTA treatment were more than 12 hr during maturation culture. In the control group, no pronuclei were detected. Our findings demonstrate that porcine immature oocytes can be parthenogenetically activated by Ca-EDTA treatment for at least 24 hr to 36 hr during maturation culture, leading to pronucleus formation followed by the formation of blastocysts. PMID:26947170

The optimal period of Ca-EDTA treatment for parthenogenetic activation of porcine oocytes during maturation culture.

PubMed

Morita, Yasuhiro; Taniguchi, Masayasu; Tanihara, Fuminori; Ito, Aya; Namula, Zhao; DO, Lanh Thi Kim; Takagi, Mitsuhiro; Takemoto, Tatsuya; Otoi, Takeshige

2016-07-01

The changes triggered by sperm-induced activation of oocytes, which are required for normal oocyte development, can be mediated by other agents, thereby inducing the parthenogenesis. In this study, we exposed porcine oocytes to 1 mM Ca-EDTA, a metal-ion chelator, at various intervals during 48 hr of in vitro maturation to determine the optimum period of Ca-EDTA treatment for parthenogenetic activation. When the oocytes were cultured with or without Ca-EDTA from 36 hr (post-12), 24 hr (post-24), 12 hr (post-36) and 0 hr (post-48) after the start of maturation culture, the blastocyst formation rates were significantly higher (P<0.05) in the post-24, post-36 and post-48 groups (3.3%, 4.0% and 2.6%, respectively) than those in the control group without treatment (0%). Furthermore, when the oocytes were cultured with Ca-EDTA for 0 hr (control), 12 hr (pre-12), 24 hr (pre-24), 36 hr (pre-36) and 48 hr (pre-48) from the start of maturation culture, the oocytes formed blastocysts only in the pre-36 and pre-48 groups (0.4% or 0.8%, respectively). Pronuclei (<66.7%) were observed only when the periods of Ca-EDTA treatment were more than 12 hr during maturation culture. In the control group, no pronuclei were detected. Our findings demonstrate that porcine immature oocytes can be parthenogenetically activated by Ca-EDTA treatment for at least 24 hr to 36 hr during maturation culture, leading to pronucleus formation followed by the formation of blastocysts.

Beneficial effect of resveratrol on bovine oocyte maturation and subsequent embryonic development after in vitro fertilization.

PubMed

Wang, Feng; Tian, XiuZhi; Zhang, Lu; He, ChangJiu; Ji, PengYun; Li, Yu; Tan, DunXian; Liu, GuoShi

2014-02-01

To analyze the potential beneficial effects and mechanisms of action of resveratrol on the maturation of bovine oocytes that were incubated in different concentrations of resveratrol (0.1, 1.0, or 10.0 μM) as germinal vesicle-stage oocytes. In vitro prospective study. University research laboratory. Animal models for human studies. In vitro culture in the presence of various concentrations of the antioxidant resveratrol. Parameters of hormone levels, oocyte nuclear maturation, cumulus expansion, levels of intracellular glutathione and reactive oxygen species, embryonic cleavage, blastocyst formation, gene expression associated with mature bovine oocytes and cumulus cells, and level of sirtuin 1 gene expression. Resveratrol statistically significantly increased progesterone secretion and decreased estradiol-17β secretion by cumulus cells. The elevated levels of progesterone activated the Mos/MEK/p42 mitogen-activated protein kinase (MAPK) cascade in the oocytes. At a concentration of 1.0 μM, resveratrol statistically significantly improved cumulus expansion, polar body formation, the (hatched) blastocyst rate, and the mean number of cells/blastocysts. Meanwhile, resveratrol statistically significantly reduced the level of reactive oxygen species (ROS) and increased the level of glutathione (GSH). For the first time, the expression of the sirtuin-1 gene was identified in granulosa cells, cumulus cells, oocytes, and blastocysts. Further studies revealed that resveratrol promoted sirtuin-1 gene expression. Resveratrol promoted bovine oocyte maturation and subsequent post-in vitro fertilization embryonic development by inducing progesterone secretion and an antioxidant effect, probably in a manner dependent on sirtuin-1. Copyright © 2014 American Society for Reproductive Medicine. All rights reserved.

Improvement of transgenic cloning efficiencies by culturing recipient oocytes and donor cells with antioxidant vitamins in cattle.

PubMed

Wongsrikeao, Pimprapar; Nagai, Takashi; Agung, Budiyanto; Taniguchi, Masayasu; Kunishi, Miho; Suto, Shizuyo; Otoi, Takeshige

2007-06-01

The present study was conducted to investigate effects of antioxidants during maturation culture of recipient oocytes and/or culture of gene-transfected donor cells on the meiotic competence of recipient oocytes, and the developmental competence and quality of the reconstructed embryos after nuclear transfer (NT) in cattle. Gene-transfected donor cells had negative effects on the proportions of blastocyst formation, total cell numbers, and DNA fragmentation indices of reconstructed embryos. Supplementation of either vitamin E (alpha-tocopherol: 100 microM) or vitamin C (ascorbic acid: 100 microM) during maturation culture significantly enhanced the cytoplasmic maturation of oocytes and subsequent development of embryos reconstructed with the oocytes and gene-transfected donor cells, but did not have synergistic effects. The supplementation of vitamin E during maturation culture of recipient oocytes increased the proportions of fusion and blastocyst formation of gene-transfected NT embryos, in which the proportions were similar to those of nontransfected NT embryos. When the gene-transfected donor cells that had been cultured with 0, 50, or 100 microM of vitamin E were transferred into recipient oocytes matured with vitamin E (100 microM), 50 microM of vitamin E increased the proportion of blastocyst formation and reduced the index of DNA fragmentation of blastocysts. In conclusion, gene-transfected donor cells have negatively influenced the NT outcome. Supplementation of vitamin E during both recipient oocyte maturation and donor cell culture enhanced the blastocyst formation and efficiently blocked DNA damage in transgenic NT embryos. (c) 2006 Wiley-Liss, Inc.

Transport of equine ovaries for assisted reproduction.

PubMed

Ribeiro, B I; Love, L B; Choi, Y H; Hinrichs, K

2008-10-01

Use of assisted reproduction to obtain foals from valuable mares post-mortem typically necessitates holding of ovaries during shipment to a laboratory. The present study evaluated whether holding ovaries briefly at a warm ( approximately 30 degrees C) temperature improves meiotic and developmental competence of oocytes, as determined after maturation in vitro and intracytoplasmic sperm injection. Ovaries were packaged in pairs in insulated containers, and held either at 24 or 25-35 degrees C for 4h, followed by cooling. Ovaries in both treatments were held for either a short (mean, 7-7.4h) or long (mean, 20.6-20.7h) duration before oocyte recovery. Control ovaries were collected en masse at the abattoir. The ovary temperature in this treatment slowly decreased to approximately 27 degrees C; oocyte recovery was performed after 3.5-7h total holding. There was no effect of temperature on oocyte meiotic or developmental competence within either treatment time period. Oocytes in the short duration holding group had similar meiotic competence to controls, but had a significantly decreased rate (P<0.05) of blastocyst development. Oocytes in the long duration holding group had decreased (P<0.05) meiotic competence and blastocyst development compared to controls. These findings indicate that storage of equine ovaries for only 7h may decrease blastocyst development, and that longer storage reduces both rate of oocyte maturation and blastocyst development. Further work is needed to determine if there is a critical time before 7h post-mortem by which equine oocytes should be recovered to maximize developmental competence.

Criteria to assess human oocyte quality after cryopreservation.

PubMed

Coticchio, G; Bonu, M A; Bianchi, V; Flamigni, C; Borini, A

2005-10-01

Oocyte cryopreservation certainly represents one of the most attractive developments in the field of assisted reproduction, with the aim of preserving female fertility and circumventing the ethical and legal drawbacks associated with embryo freezing. Despite the achievement of the first pregnancy from frozen oocytes dating back as early as 1987, since then fewer than 150 pregnancies have been reported. Over a long period of time, application of oocyte storage on a large scale has been prevented by various factors, namely poor post-thaw survival. Fertilization rates remained low even after the introduction of intracytoplasmic sperm injection. Modifications of slow-freezing protocols, mainly based on the increase of the concentration of sucrose used as non-penetrating cryoprotectant (CPA) and the replacement of sodium with choline, appear to have decisively improved survival rates to over 80%. Investigations at the cellular level on thawed oocytes are largely lacking. Fertilization rates have also benefited from protocol modifications, reaching values indistinguishable from those normally obtained with fresh material. Vitrification protocols have also been tested, giving rise to improvements whose reproducibility is still uncertain. Data on the dynamics of fertilization and preimplantation development of embryos derived from frozen oocytes are extremely scarce. At the moment, clinical efficiency of oocyte cryopreservation cannot be precisely assessed because of the lack of controlled studies, although it appears to be considerably lower than that achieved with embryo freezing. In summary, encouraging advances have been made in the field of oocyte cryopreservation, but presently no protocol can ensure standards of success and safety comparable to those guaranteed by embryo storage.

The negative influence of sperm cryopreservation on the quality and development of the embryo depends on the morphology of the oocyte.

PubMed

Braga, D P A F; Setti, A S; Figueira, R C S; Iaconelli, A; Borges, E

2015-07-01

The present case-control study aimed to identify the effect of sperm cryopreservation on the quality of the embryo and on the probability of blastocyst formation when oocytes free of dimorphisms are injected and when at least one dymorphism is present. The study included 22 186 zygotes, obtained from 2802 patients undergoing intracytoplasmic sperm injection cycles, in a private assisted reproduction center, using either fresh or cryopreserved sperm. The effect of sperm cryopreservation on the embryo quality on cleavage stage and blastocyst formation chance were evaluated when oocytes free of dimorphisms are injected and when at least one dymorphism is present. The quality of the embryo on cleavage stage as well as the chance for blastocyst formation was not influenced by the origin of the spermatozoa when the quality of the oocyte was not considered. When at least one oocyte defect was present, a negative influence of sperm cryopreservation on cleavage stage embryo quality and the chance for blastocyst formation was noted. In oocytes with extra-cytoplasmic dimorphisms, the injection of cryopreserved sperm did not affect the quality of the embryo during the cleavage stage, but did affect the chance for blastocyst formation. Conversely, in oocytes with intracytoplasmic defects, the quality of the embryos on cleavage stage and the chance of blastocyst formation were negatively influenced by the injection of cryopreserved sperm. The results suggest an oocyte quality-dependent negative effect of sperm cryopreservation on embryo quality and on the probability of blastocyst formation. © 2015 American Society of Andrology and European Academy of Andrology.

Biosynthesis and secretion of catalytically active acetylcholinesterase in Xenopus oocytes microinjected with mRNA from rat brain and from Torpedo electric organ.

PubMed

Soreq, H; Parvari, R; Silman, I

1982-02-01

A novel technique was developed for monitoring the level of the mRNA species that direct the synthesis of acetylcholinesterase (AcChoEase; acetylcholine acetylhydrolase, EC 3.1.1.7), using microinjected Xenopus oocytes as a translation system. When injected with poly(A)-containing RNA from whole rat brain or rat cerebellum and from electric organ of Torpedo ocellata, Xenopus oocytes synthesize and secrete catalytically active cholinesterase. The newly synthesized enzyme, which is mostly secreted into the oocytes incubation medium, appears to be primarily AcChoEase because it is inhibited by the specific inhibitor BW 284C51. The new enzymatic activity can be detected after injection of as little as 12.5 ng of poly(A)-containing RNA per oocyte, and there is a linear dependence of the oocytes' ability to form AcChoEase on the amount of injected RNA. The AcChoEase mRNA displays a tau 1/2 of about 10 +/- 3 hr in injected oocytes. The abundance of AcChoEase mRNA in the total nonfractionated mRNA injected was calculated to be ca. 1 x 10(-5), a value similar to the level of AcChoEase protein determined in rat brain. The combination of the high turnover number of AcChoEase, the efficiency of the oocyte system, and the sensitivity of the assay used thus permit the accurate monitoring of the scarce mRNA species that direct the synthesis of this enzyme.

Insect water-specific aquaporins in developing ovarian follicles of the silk moth Bombyx mori: role in hydration during egg maturation.

PubMed

Maruyama, Mariya; Kambara, Kohei; Naka, Hideshi; Azuma, Masaaki

2015-08-01

Egg formation in terrestrial insects is an absorptive process, accommodated not only by packing proteins and lipids into yolk but also by filling chorions with water. An osmotic swelling of ovarian follicles takes place during oocyte maturation. This study investigated the role of the aquaporin (AQP) water channel in the osmotic uptake of water during oogenesis in the silk moth Bombyx mori Linnaeus, 1758. Using the antibodies that specifically recognize previously characterized AQPs, two water-specific subtypes-AQP-Bom1 and AQP-Bom3-belonging to the Drosophila integral protein (DRIP) and Pyrocoelia rufa integral protein (PRIP) subfamilies of the insect AQP clade, respectively, were identified in the developing ovaries of B. mori. During oocyte growth, Bombyx PRIP was distributed at the oocyte plasma membrane, where it likely plays a role in water uptake and oocyte swelling, and may be responsible for oocyte hydration during fluid absorption by ovarian follicles. During the transition from vitellogenesis to choriogenesis during oocyte maturation, Bombyx DRIP expression became abundant in peripheral yolk granules underlying the oocyte plasma membrane. The restricted DRIP localization was not observed in non-diapause-destined follicles, where DRIP was evenly distributed in medullary yolk granules. There was no difference in PRIP distribution between diapause- and non-diapause-destined follicles. The diapause-destined oocytes encase DRIP protein in the peripheral yolk granules, where DRIP might be inert. This would be reflected in the metabolic arrest associated with diapause after fertilization and egg oviposition. © 2015 Marine Biological Laboratory.

Perceptions of oocyte banking from women intending to circumvent age-related fertility decline.

PubMed

de Groot, Marije; Dancet, Eline; Repping, Sjoerd; Goddijn, Mariette; Stoop, Dominic; van der Veen, Fulco; Gerrits, Trudie

2016-12-01

Women can now opt to bank their oocytes with the intention of increasing their chances of achieving a pregnancy after their fertility has declined. This exploratory study aimed to gain insight into how women, considering oocyte banking to circumvent age-related fertility decline, perceive this intervention. We conducted a qualitative study in a Dutch university medical center and held in-depth interviews with women on the waiting list for oocyte banking. We recorded the interviews, transcribed them verbatim and used thematic analysis. All women were financially independent and lived in single-person urban households. They opted for oocyte banking because they wished to share parenthood with a future partner rather than becoming a single parent. This strong desire was key in their interpretation of all aspects of the intervention. Women set aside information about the limited success rates and potential risks, as they were optimistic about their own prognosis, thought that the chances for success were equally likely as the chances it would fail, and because of "anticipatory regret". They perceived oocyte banking as a "helping hand" to achieve shared parenthood. Although women found the costs of the intervention high, they were willing to invest their money to increase their chances for shared parenthood. Oocyte banking allows women to circumvent age-related fertility decline. The prospect of potential shared parenthood overrules the perceived health risks and burden. Health professionals should take this into account when informing potential users of oocyte banking. © 2016 Nordic Federation of Societies of Obstetrics and Gynecology.

Effects of nuclear transfer procedures on ES cell cloning efficiency in the mouse.

PubMed

Yabuuchi, Akiko; Yasuda, Yoshiko; Kato, Yoko; Tsunoda, Yukio

2004-04-01

Enucleated oocytes receiving mouse embryonic stem (ES) cells develop into fertile young. The developmental potential to young is low, however, and the rate of postnatal death is high. We examined the effect of various nuclear transfer procedures on the in vitro and in vivo developmental potential of nuclear-transferred oocytes. The potential of oocytes receiving ES cells at M phase to develop into blastocysts after fusion by Sendai virus was high compared with that after direct injection (67% vs. 30%). The developmental potential of oocytes receiving ES cells at the M phase is higher than that of oocytes receiving ES cells at the G(1) phase (30-67% vs. 2-5%). Developmental ability to live young was low in all groups (0-4%). Different activation protocols affected the potential to develop into blastocysts to a different extent (27-62%), but did not affect the potential to develop into live young (0-3%). The present study demonstrated that the various conditions examined did not affect the potential of nuclear-transferred oocytes receiving ES cells to develop into live young or the incidence of postnatal death.

Differential sensitivity of mouse oocytes to colchicine-induced aneuploidy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mailhes, J.B.; Yuan, Z.P.

1987-01-01

Unpublished results from our laboratory showed that colchicine increased the incidence of hyperploid mouse metaphase II (MII) oocytes when injected at the same time as human chorionic gonadotrophin (HCG). The objective of the present study was to determine whether the time of administering colchicine influenced the incidence of aneuploidy in MII oocytes. CD-1 mice were given pregnant mare's serum (PMS) and, 48 hr later, HCG. An intraperitoneal injection of 0.2 mg/kg colchicine was given at +4, +2, 0, -2, or -4 hr relative to HCG. Oocytes were collected 17 hr post-HCG and processed, and chromosomes were subsequently C-banded. The percentagemore » of hyperploid oocytes was 0.77, 2.56, 5.71, 7.79, 3.54, and 2.70 for control, +4, +2, 0, -2, or -4 hr pre/post-HCG, respectively. Chi-square analyses of these data demonstrated that colchicine significantly increases the proportion of aneuploid oocytes, and that the relative sensitivity of colchicine-induced aneuploidy depends upon the time that this drug is administered relative to HCG.« less

Investigations of oocyte in vitro maturation within a mouse model.

PubMed

Chin, Alexis Heng Boon; Chye, Ng Soon

2004-02-01

This study attempted to develop a 'less meiotically competent' murine model for oocyte in vitro maturation (IVM), which could more readily be extrapolated to human clinical assisted reproduction. Oocyte meiotic competence was drastically reduced upon shortening the standard duration of in vivo gonadotrophin stimulation from 48 h to 24 h, and by selecting only naked or partially naked germinal vesicle oocytes, instead of fully cumulus enclosed oocyte complexes. With such a less meiotically competent model, only porcine granulosa coculture significantly enhanced the oocyte maturation rate in vitro, whereas no significant enhancement was observed with macaque and murine granulosa coculture. Increased serum concentrations and the supplementation of gonadotrophins, follicular fluid and extracellular matrix gel within the culture medium did not enhance IVM under either cell-free or coculture conditions. Culture medium conditioned by porcine granulosa also enhanced the maturation rate, and this beneficial effect was not diminished upon freeze-thawing. Enhanced IVM in the presence of porcine granulosa coculture did not, however, translate into improved developmental competence, as assessed by in vitro fertilization and embryo culture to the blastocyst stage.

Daam1 regulates fascin for actin assembly in mouse oocyte meiosis.

PubMed

Lu, Yujie; Zhang, Yu; Pan, Meng-Hao; Kim, Nam-Hyung; Sun, Shao-Chen; Cui, Xiang-Shun

2017-07-18

As a formin protein, Daam1 (Dishevelled-associated activator of morphogenesis 1) is reported to regulate series of cell processes like endocytosis, cell morphology and migration via its effects on actin assembly in mitosis. However, whether Daam1 plays roles in female meiosis remains uncertain. In this study, we investigated the expression and functions of Daam1 during mouse oocyte meiosis. Our results indicated that Daam1 localized at the cortex of oocytes, which was similar with actin filaments. After Daam1 morpholino (MO) microinjection, the expression of Daam1 significantly decreased, which resulted in the failure of oocyte polar body extrusion. These results might be due to the defects of actin assembly, since the decreased fluorescence intensity of actin filaments in oocyte cortex and cytoplasm were observed. However, Daam1 knockdown seemed not to affect the meiotic spindle movement. In addition, we found that fascin might be the down effector of Daam1, since the protein expression of fascin decreased after Daam1 knockdown. Thus, our data suggested that Daam1 affected actin assembly during oocyte meiotic division via the regulation of fascin expression.

Exposure to cadmium during in vitro maturation at environmental nanomolar levels impairs oocyte fertilization through oxidative damage: A large animal model study.

PubMed

Martino, N A; Marzano, G; Mangiacotti, M; Miedico, O; Sardanelli, A M; Gnoni, A; Lacalandra, G M; Chiaravalle, A E; Ciani, E; Bogliolo, L; Minervini, F; Pizzi, F; Dell'Aquila, M E

2017-04-01

Cadmium is a highly toxic heavy metal with negative effects on oocyte fertilization. The aim of this study was to analyse whether cadmium-induced impairment of fertilization is caused by mitochondria dysfunction and oxidative stress in the cumulus-oocyte complex (COC). Preliminarily, 19 trace element levels were measured in ovaries from juvenile and adult ewes and age-related cadmium ovarian bioaccumulation at nanomolar concentrations was found. COCs from juvenile and adult ewes, exposed during in vitro maturation to 1nM or 100nM CdCl 2 , and subjected to in vitro fertilization showed significantly lower fertilization rates in exposed COCs compared with controls. In vitro matured exposed and control COCs underwent confocal microscopy analysis of mitochondria activity and reactive oxygen species (ROS) levels and lipid peroxidation (LPO) assay at cumulus cell and oocyte level. In both age groups, cadmium at nanomolar concentrations induced cumulus-oocyte mitochondria over-activity and oxidative damage which were related to impaired oocyte fertilization. Copyright © 2017 Elsevier Inc. All rights reserved.

GnRHa to trigger final oocyte maturation: a time to reconsider.

PubMed

Humaidan, P; Papanikolaou, E G; Tarlatzis, B C

2009-10-01

Recently GnRH antagonist protocols for the prevention of a premature LH surge were introduced, allowing final oocyte maturation to be triggered with a single bolus of a GnRH agonist (GnRHa). GnRHa is as effective as hCG for the induction of ovulation, and apart from the LH surge a FSH surge is also induced. Until recently, prospective randomized studies reported a poor clinical outcome when GnRHa was used to trigger final oocyte maturation in IVF/ICSI antagonist protocols, presumably due to a luteal phase deficiency, despite standard luteal phase supplementation with progesterone and estradiol. As GnRHa triggering of final oocyte maturation could possess advantages over hCG triggering in terms of a reduced if not eliminated risk of ovarian hyperstimulation syndrome (OHSS) and the retrieval of more mature oocytes, the challenge has been to rescue the luteal phase. In the literature now several studies report a luteal phase rescue with a reproductive outcome comparable to that of hCG induced final oocyte maturation. Although more research is needed, GnRHa triggering is now a valid alternative with potential benefits.