Tsunoda, Satoshi; Kawano, Natsuko; Miyado, Kenji; Kimura, Naoko; Fujii, Junichi
The oxidative modification of gametes by a reactive oxygen species is a major deleterious factor that decreases the successful rate of in vitro fertilization. Superoxide dismutase 1 (SOD1) plays a pivotal role in antioxidation by scavenging the superoxide anion, and its deficiency causes infertility in female mice, but the significance of the enzyme in male mice remains unclear. In the present study, we characterized Sod1(-/-) (Sod1-KO) male reproductive organs and compiled the first report of the impaired fertilizing ability of Sod1-KO sperm in in vitro fertilization. Insemination of wild-type oocytes with Sod1-KO sperm exhibited lower rates of fertility compared with insemination by wild-type sperm. The low fertilizing ability found for Sod1-KO sperm was partially rescued by reductant 2-mercaptoethanol, which suggested the oxidative modification of sperm components. The numbers of motile and progressive sperm decreased during the in vitro fertilization process, and a decline in ATP content and elevation in lipid peroxidation occurred in the Sod1-KO sperm in an incubation time-dependent manner. Tyrosine phosphorylation, which is a hallmark for sperm capacitation, was also impaired in the Sod1-KO sperm. These results collectively suggest that machinery involved in sperm capacitation and motility are vulnerable to oxidative damage during the in vitro fertilization process, which could increase the rate of inefficient fertilization.
Ducha, Nur; Susilawati, T; Aulanni'am; Wahyuningsih, Sri; Pangestu, Mulyoto
Sperm can change physiology and structure during storage in refrigerator temperature or frozen temperature that caused by cold shock or free radical. The aim of this study to evaluate ultrastructure and fertilizing ability of Limousin bull sperm after storage in cauda epididymal plasma-based (CEP-2) extender with or without 20% egg yolk concentration at refrigerator temperature. Semen sample collected from three Limousin bull were diluted with CEP-2 with 20% egg yolk and CEP-2 without egg yolk, cooled and stored at 4-5 degrees C during eight days. Sperm ultrastructure were observed with scanning electron microscopy (SEM). Fertilizing ability of Limousin bull sperm were assessed on cleavage rate of embryo using in vitro fertilization method. The percentage data were transformed into arcsine before being analysis with ANOVA and Duncan's multiple comparison test. The result of study showed morphologically normal sperm after storage in CEP-2 with 20% egg yolk, whereas in CEP-2 without egg yolk morphologically abnormal sperm especially neck was fractured and head was destroyed. Fertilizing ability of Limousin bull sperm were significantly higher in CEP-2 extender with egg yolk 20% (74.29 +/- 4.95%; p < 0.05) than without egg yolk (30.00 +/- 12.02%; p < 0.05). Egg yolk 20% in CEP-2 extender protected ultrastructure and fertilizing ability after storage during eight days.
Thuwanut, Paweena; Arya, Nlin; Comizzoli, Pierre; Chatdarong, Kaywalee
Intracellular adenosine 5'-triphosphate (ATP) is essential for supporting sperm function in the fertilization process. During cryopreservation, damage of sperm mitochondrial membrane usually leads to compromised production of intracellular ATP. Recently, extracellular ATP (ATPe) was introduced as a potent activator of sperm motility and fertilizing ability. This study aimed to evaluate (1) levels of intracellular ATP in frozen-thawed epididymal cat sperm after incubation with ATPe and (2) effects of ATPe on epididymal cat sperm parameters after freezing and thawing. Eighteen male cats were included. For each replicate, epididymal sperm from two cats were pooled to one sample (N = 9). Each pooled sample was cryopreserved with the Tris-egg yolk extender into three straws. After thawing, the first and second straws were incubated with 0-, 1.0-, or 2.5-mM ATPe for 10 minutes and evaluated for sperm quality at 10 minutes, 1, 3, and 6 hours after thawing and fertilizing ability. The third straw was evaluated for intracellular ATP concentration in control and with 2.5-mM ATPe treatment. Higher concentration of intracellular sperm ATP was observed in the samples treated with 2.5-mM ATPe compared to the controls (0.339 ± 0.06 μg/2 × 10(6) sperm vs. 0.002 ± 0.003 μg/2 × 10(6) sperm, P ≤ 0.05). In addition, incubation with 2.5-mM ATPe for 10 minutes promoted sperm motility (56.7 ± 5.0 vs. 53.3 ± 4.4%, P ≤ 0.05) and progressive motility (3.1 ± 0.2 vs. 2.8 ± 0.4, P ≤ 0.05), mitochondrial membrane potential (36.4 ± 5.5 vs. 28.7 ± 4.8%, P ≤ 0.05), and blastocyst rate (36.1 ± 7.0 and 28.8 ± 7.4%, P ≤ 0.05) compared with the controls. In contrast, ATPe remarkably interfered acrosome integrity after 6 hours of postthawed incubation. In sum, the present finding that optimal incubation time of postthaw epididymal cat sperm under proper ATPe condition might constitute a rationale for the studies on other endangered wild felids regarding sperm quality and embryo
Kolb, B A; Acosta, V C; Jeyendran, R S
Cryopreserved sperm is less fertile than fresh sperm; probably due to dependence of sperm to glycerol, a common cryoprotective agent. Few data suggest any correlations between standard semen analysis and fertility. To develop a reliable assay, the authors hypothesized that sperm that withstand the physiochemical stress induced by glycerol during cryopreservation may have higher fertility potential. They analyzed 55 cryopreserved semen samples for sperm concentration, percent motility and progressive motility after allowing thawed sperm to migrate into medium containing either 0 or 12% glycerol for 3 h. The smaller the difference in sperm quality between the two media, the higher the fertility potential of the spermatozoa. There was significant negative correlation between the difference in both percent sperm motility and percent progressive sperm motility in the two media and in vitro fertilization outcome. There was a significantly higher number of ejaculates fertilized oocytes at a rate of > or = 80% when the difference was 20% or less. This easy to use, inexpensive test may be an effective means to evaluate the potential performance of cryopreserved sperm to be utilized in assisted reproductive technologies.
Kaya, Abdullah; Memili, Erdoğan
Bull fertility, ability of the sperm to fertilize and activate the egg that sustain embryo development, is vitally important for effective and efficient production of cattle. Fertility is a complex trait with low heritability. Despite recent advances in genomic selection and possibility of enormous paternal benefits to profitable cattle production, there exist no reliable tests for evaluating semen quality and predicting bull fertility. This review focuses on sperm macromolecules such as transcripts, proteins and the epigenome, i.e., the functional genome that are associated with bull fertility. Generating new information in these systems is important beyond agriculture because such progress advances the fundamental science of the mammalian male gamete while at the same time introduces biotechnology into livestock production. Sperm macromolecules and epigenome markers associated with bull fertility can be used alone or in combination with the current SNP microarrays to determine sperm quality and to indicate bull fertility.
Healthy Lifestyle Getting pregnant Healthy sperm aren't always a given. Understand how lifestyle factors can affect your ... as a laptop, might enhance sperm quality. Adopting healthy lifestyle practices to promote your fertility — and avoiding things ...
Gray, Jeffrey Earl
Cryopreservation of mouse sperm is an important technology for management of biomedical research resources. Dramatic progress has been made recently in the development of protocols that combat mouse-strain specific reduction of IVF after cryopreservation. Equal emphasis, however, has not been placed on investigating the biological mechanisms underlying these improvements to IVF. This dissertation broadly investigates the basic question of how mouse-strain specific reduction of IVF occurs after cryopreservation, and how recently developed protocols prevent this process. My research investigated the effects of antioxidants, the cholesterol-acceptor CD, reduced calcium media, and TYH capacitation media on sperm function and oxidative stress after cryopreservation in a variety of mouse strains. I found that reduced IVF was associated with loss of capacitation-dependent sperm function in three strains, B6/J, B6/N, and 129X1, and CD improved sperm function and IVF in all three strains. These findings suggest that cryopreservation inhibits cholesterol efflux resulting in reduced IVF of many mouse strains. I also found that cryopreservation induces uniquely high production of mitochondrial H2O2 by B6/J sperm. H2O2 present in other cellular compartments of B6/J sperm was not elevated compared to other strains. High levels of mitochondrial H2O2 were associated with lipid peroxidation of the sperm head and inability to acrosome react. Antioxidants reduced mitochondrial H2O2 production, decreased sperm head lipid peroxidation, and improved acrosome reaction. The cryopreservation-induced increase in mitochondrial H2O2 production of B6/J and B6129XF1 sperm was associated with elevation of intracellular calcium after cryopreservation and dependent on mitochondrial metabolic substrates. Reducing intracellular calcium levels or removing mitochondrial metabolic substrates decreased mitochondrial H2O2 production and increased IVF rates of cryopreserved B6/J sperm. Many of the strains
Bosakova, Zuzana; Tockstein, Antonin; Adamusova, Hana; Coufal, Pavel; Sebkova, Natasa; Dvorakova-Hortova, Katerina
Fluorides and fluoroaluminates decrease mouse sperm fertilizing potential by modifying the process of sperm preparation for fertilization, so-called capacitation, followed by acrosome reaction (AR). Capacitation was monitored by protein tyrosine phosphorylation (pTyr), and AR was induced consequently. The aim of this study was to apply kinetic analysis to the previously obtained dependences of pTyr and AR at capacitation times, and propose a mathematical theory for a mechanism when sperm maturation ability is amended by external stimuli. The experimental input data, previously obtained, are consistent with the proposed theory and the results of kinetic analysis show that sperm capacitation runs as two subsequent first-order steps. Firstly, an unstable intermediate is formed and then gradually decomposes. The time corresponding to the maximal production of the unstable intermediate is probably most suitable for sperm obtaining the ability to fertilize the egg. The presented calculations indicate that the application of kinetic analysis can serve as a tool to predict or confirm a course of biological events that are modified by external factors, and therefore the proposed theory shall be of interest to a broad scientific audience.
Bacci, M L; Zannoni, A; De Cecco, M; Fantinati, P; Bernardini, C; Galeati, G; Spinaci, M; Giovannoni, R; Lavitrano, M; Seren, E; Forni, M
A simple and efficient method for producing multitransgenic animals is required for medical and veterinary applications. Sperm-mediated gene transfer (SMGT) is an effective method for introducing multiple genes into pigs (Sus, Sus scrofa). The major benefits of this technique are the high efficiency, low cost, and ease of use compared with that of other methods: Sperm-mediated gene transfer does not require embryo handling or expensive equipment. The aim of this study was to investigate the influence of SMGT treatment and exogenous DNA uptake on sperm quality. Even after a coincubation with a 20-fold larger amount (100 microg/mL) of DNA than usual (5 microg/mL), sperm quality parameters were not significantly affected, confirming the hypothesis that the SMGT protocol itself or the amount of bound DNA do not compromise the possibility of an extended employment of SMGT. More importantly, we found that semen used for in vitro fertilization 24h after DNA uptake gave good cleavage (60% vs. 58%, treated vs. control) and developmental rates definitely positive (41% vs. 48%, treated vs. control). These good results are connected to a competitive efficiency of transformation (62%) due to the numerous improvements in SMGT technique. We demonstrate that SMGT-treated spermatozoa retain good quality and fertilization potential for at least 24h, expanding the possibility to apply transgenesis in field conditions in swine, where the greatest hurdles are fertilization timing and plain procedure.
Simmons, Leigh W; Fitzpatrick, John L
Females frequently mate with several males, whose sperm then compete to fertilize available ova. Sperm competition represents a potent selective force that is expected to shape male expenditure on the ejaculate. Here, we review empirical data that illustrate the evolutionary consequences of sperm competition. Sperm competition favors the evolution of increased testes size and sperm production. In some species, males appear capable of adjusting the number of sperm ejaculated, depending on the perceived levels of sperm competition. Selection is also expected to act on sperm form and function, although the evidence for this remains equivocal. Comparative studies suggest that sperm length and swimming speed may increase in response to selection from sperm competition. However, the mechanisms driving this pattern remain unclear. Evidence that sperm length influences sperm swimming speed is mixed and fertilization trials performed across a broad range of species demonstrate inconsistent relationships between sperm form and function. This ambiguity may in part reflect the important role that seminal fluid proteins (sfps) play in affecting sperm function. There is good evidence that sfps are subject to selection from sperm competition, and recent work is pointing to an ability of males to adjust their seminal fluid chemistry in response to sperm competition from rival males. We argue that future research must consider sperm and seminal fluid components of the ejaculate as a functional unity. Research at the genomic level will identify the genes that ultimately control male fertility.
Neri, Queenie V; Lee, Bora; Rosenwaks, Zev; Machaca, Khaled; Palermo, Gianpiero D
Since the establishment of in vitro fertilization, it became evident that almost half of the couples failed to achieve fertilization and this phenomenon was attributed to a male gamete dysfunction. The adoption of assisted fertilization techniques particularly ICSI has been able to alleviate male factor infertility by granting the consistent ability of a viable spermatozoon to activate an oocyte. Single sperm injection, by pinpointing the beginning of fertilization, has been an invaluable tool in clarifying the different aspects of early fertilization and syngamy. However, even with ICSI some couples fail to fertilize due to ooplasmic dysmaturity in relation to the achieved nuclear maturation marked by the extrusion of the first polar body. More uncommon are cases where the spermatozoa partially or completely lack the specific oocyte activating factor. In this work, we review the most relevant aspects of fertilization and its failure through assisted reproductive technologies. Attempts at diagnosing and treating clinical fertilization failure are described.
Neri, Queenie V.; Lee, Bora; Rosenwaks, Zev; Machaca, Khaled; Palermo, Gianpiero D.
Summary Since the establishment of in vitro fertilization, it became evident that almost half of the couples failed to achieve fertilization and this phenomenon was attributed to a male gamete dysfunction. The adoption of assisted fertilization techniques particularly ICSI has been able to alleviate male factor infertility by granting the consistent ability of a viable spermatozoon to activate an oocyte. Single sperm injection, by pinpointing the beginning of fertilization, has been an invaluable tool in clarifying the different aspects of early fertilization and syngamy. However, even with ICSI some couples fail to fertilize due to ooplasmic dysmaturity in relation to the achieved nuclear maturation marked by the extrusion of the first polar body. More uncommon are cases where the spermatozoa partially or completely lack the specific oocyte activating factor. In this work, we review the most relevant aspects of fertilization and its failure through assisted reproductive technologies. Attempts at diagnosing and treating clinical fertilization failure are described. PMID:24290744
Flowers, W L
Current industry estimates of reproductive performance for cattle, sheep, and swine operations indicate that males contribute significantly to fertility failures. This appears to be due to the use of subfertile individuals and emphasizes the need for additional research in identifying characteristics of sperm that compromise fertilization. In theory, sperm characteristics, such as motility or the percentage of normal sperm, form a positive relationship with fertility that reaches a certain maximal fertility (i.e., an asymptotic relationship). It is clear that variation exists among males in terms of how fertility responds to increasing sperm dosage or numbers of normal sperm, both in the slope of the curve and the point at which the fertility reaches a maximum. Variations along the linear portion of fertility curves are due to compensable traits that are involved with the ability of sperm to penetrate the zona pellucida. It appears that most fertility curves reach their plateau when 70% of sperm possess a given compensable trait. The level of fertility at which the plateau occurs is determined by noncompensable traits that are associated with binding of sperm to the oolemma, syngamy, and subsequent development of the zygote. Several studies have shown differences in fertility among males that have similar levels of compensable traits but differed in their noncompensable characteristics. Compensable and noncompensable traits can estimate either individual or functional characteristics of sperm. Intuitively, functional traits such as in vitro penetration should provide a better indication of fertilization than individual ones such as motility. However, correlations of both types with fertility are very similar. Reasons for this may be related to how characteristics of sperm cells are influenced by the female reproductive tract after insemination. Sperm capacitation is a functional trait in boars that is quite different in vitro versus in vivo. If this relationship
García-Vázquez, Francisco A; Gadea, Joaquín; Matás, Carmen; Holt, William V
After natural or artificial insemination, the spermatozoon starts a journey from the site of deposition to the place of fertilization. However, only a small subset of the spermatozoa deposited achieves their goal: to reach and fertilize the egg. Factors involved in controlling sperm transport and fertilization include the female reproductive tract environment, cell-cell interactions, gene expression, and phenotypic sperm traits. Some of the significant determinants of fertilization are known (i.e., motility or DNA status), but many sperm traits are still indecipherable. One example is the influence of sperm dimensions and shape upon transport within the female genital tract towards the oocyte. Biophysical associations between sperm size and motility may influence the progression of spermatozoa through the female reproductive tract, but uncertainties remain concerning how sperm morphology influences the fertilization process, and whether only the sperm dimensions per se are involved. Moreover, such explanations do not allow the possibility that the female tract is capable of distinguishing fertile spermatozoa on the basis of their morphology, as seems to be the case with biochemical, molecular, and genetic properties. This review focuses on the influence of sperm size and shape in evolution and their putative role in sperm transport and selection within the uterus and the ability to fertilize the oocyte. PMID:27624988
Buarpung, S; Tharasanit, T; Comizzoli, P; Techakumphu, M
Cryopreservation of testicular tissue associated with intracytoplasmic sperm injection (ICSI) is a critical tool that still needs to be explored for preserving the fertility of endangered species. Using the domestic cat as a model for wild felids, the study aimed at determining the effect of different cryoprotectants and freezing techniques (two-step freezing vs. controlled slow freezing) on the sperm quality (membrane and DNA integrity). Then, spermatozoa were extracted from frozen-thawed testicular tissues and used for ICSI to assess early gamete activation or developmental competence in vitro. The percentage of spermatozoa with intact plasma membrane was not different (P > 0.05) among nonfrozen control, glycerol-, and ethylene glycol-frozen tissues (63.2 ± 2%, 58.2 ± 2.6%, 53.3 ± 2.3%, respectively). However, these percentages were significantly lower (P < 0.05) in groups of dimethyl sulfoxide (46.3 ± 3.3%) and 1,2 propanediol (44.3 ± 2.9%) when compared with control. Conventional freezing combined with 5% (vol/vol) glycerol best preserved sperm membrane integrity (55.0 ± 2.7%) when compared with other freezing techniques. The incidence of DNA fragmentation was found to be low (0.2%-1.1%) in all freezing protocols. After ICSI with frozen testicular spermatozoa, male and female gametes were asynchronously activated and the percentages of normal fertilization at 6, 12, and 18 hours were 11.2%, 20.6%, and 22.1%, respectively. Metaphase II-arrested oocytes containing or not a decondensed sperm head were predominantly found after ICSI with frozen testicular spermatozoa. Although two-pronucleus formation could be observed as soon as 6 hours post ICSI (10%), the rate increased dramatically after 12 and 18 hours post ICSI (17.2% and 19.5%, respectively). ICSI using frozen-thawed testicular spermatozoa yielded cleavage (32.7%), morula (6.5%), and blastocyst (4.4%) percentages similar to nonfrozen control (P > 0.05). It is concluded that conventional freezing
... decide whether a couple should use in vitro fertilization (IVF) to attempt a pregnancy. It is best ... genetic material. Once the sperm enters the egg, fertilization has a good chance of taking place. However, ...
Sperm concentration and count are often used as indicators of environmental impacts on male reproductive health. Existing clinical databases may be biased towards subfertile men with low sperm counts and less is known about expected sperm count distributions in cohorts of fertil...
Fertilization and development of the preimplantation embryo is under genetic control. The goal of the current study was to test 434 single nucleotide polymorphisms (SNPs) for association with genetic variation in fertilization and early embryonic development. The approach was to produce embryos from...
Öğretmen, Fatih; İnanan, Burak Evren; Kutluyer, Filiz; Kayim, Murathan
Amino acids have an important biological role for prevention of cell damage during cryopreservation. The objective of this study is to determine the effects of cysteine on postthaw sperm motility, duration of sperm motility, DNA damage, and fertility in the common carp (Cyprinus carpio). Sperm collected from 10 individuals was cryopreserved in extenders containing different cysteine concentrations (2.5, 5, 10, and 20 mM). Semen samples diluted at the ratio of 1:9 by the extenders were subjected to cryopreservation. After dilution, the semen was aspirated into 0.25-mL straws; the straws were placed on the tray, frozen in nitrogen vapor, and plunged into liquid nitrogen. DNA damage was evaluated by comet assay after cryopreservation. Our results indicated that an increase in the concentration of cysteine caused a significant increase in the motility rate and duration of sperm in the common carp (C carpio; P < 0.05). Comparing all concentrations of cysteine, the best concentration of cysteine was 20 mM. Higher postthaw motility (76.00 ± 1.00%) and fertilization (97.00 ± 1.73%) rates were obtained with the extender at the concentration of 20 mM. Supplementation of the extender with cysteine was increased the fertilization and hatching rate and decreased DNA damage. Consequently, cysteine affected the motility, fertilization, and DNA damage positively, and extenders could be supplemented with cysteine.
Shi, Xiao; Wang, Ting; Qiu, Zhuo Lin; Li, Ke; Li, Liu; Chan, Carol Pui Shan; Chan, Si Mei; Li, Tian-Chiu; Quan, Song
In this study, we investigated whether any of the observed changes in mouse sperm function tests secondary to mechanical stresses (centrifugation and pipetting) correlate with sperm fertilization ability. Chinese Kunming mice were used as sperm and oocyte donors. Sperm samples were allocated evenly into centrifugation, pipette, and control groups. Sperm plasma membrane integrity (PMI), mitochondrial membrane permeability (MMP), baseline and stimulated intracellular ROS, and sperm fertilization ability were measured by hypo-osmotic swelling, flow cytometry, and fertilization tests. Parallel studies were conducted and all tests were repeated six times. Our results showed that after centrifugation, the progressive motility, average path velocity, and overall sperm motility and PMI decreased significantly (p < 0.05). In addition, the MMP level decreased significantly in viable sperm when the centrifugation condition reached 1,400 g × 15 minutes (p < 0.05). When pipetting was performed two or more times, progressive motility, average path velocity, and overall sperm motility decreased significantly (p < 0.05); when it was performed four or more times, sperm membrane integrity and intracellular basal ROS level of viable sperm was also significantly decreased (p < 0.05). In conclusion, various mechanical stresses seem to affect sperm function, however this does not appear to alter fertilization rate. Laboratory handling steps should be minimized to avoid unnecessary mechanical stresses being applied to sperm samples.
Bennison, Clair; Hemmings, Nicola; Slate, Jon; Birkhead, Tim
Sperm competition, in which the ejaculates of multiple males compete to fertilize a female's ova, results in strong selection on sperm traits. Although sperm size and swimming velocity are known to independently affect fertilization success in certain species, exploring the relationship between sperm length, swimming velocity and fertilization success still remains a challenge. Here, we use the zebra finch (Taeniopygia guttata), where sperm size influences sperm swimming velocity, to determine the effect of sperm total length on fertilization success. Sperm competition experiments, in which pairs of males whose sperm differed only in length and swimming speed, revealed that males producing long sperm were more successful in terms of (i) the number of sperm reaching the ova and (ii) fertilizing those ova. Our results reveal that although sperm length is the main factor determining the outcome of sperm competition, complex interactions between male and female reproductive traits may also be important. The mechanisms underlying these interactions are poorly understood, but we suggest that differences in sperm storage and utilization by females may contribute to the outcome of sperm competition. PMID:25621327
Browne, R K; Kaurova, S A; Uteshev, V K; Shishova, N V; McGinnity, D; Figiel, C R; Mansour, N; Agney, D; Wu, M; Gakhova, E N; Dzyuba, B; Cosson, J
We review the phylogeny, sperm competition, morphology, physiology, and fertilization environments of the sperm of externally fertilizing fish and amphibians. Increased sperm competition in both fish and anurans generally increases sperm numbers, sperm length, and energy reserves. The difference between the internal osmolarity and iconicity of sperm cells and those of the aquatic medium control the activation, longevity, and velocity of sperm motility. Hypo-osmolarity of the aquatic medium activates the motility of freshwater fish and amphibian sperm and hyperosmolarity activates the motility of marine fish sperm. The average longevity of the motility of marine fish sperm (~550 seconds) was significantly (P < 0.05) greater than that of freshwater fish sperm (~150 seconds), with the longevities of both marine and freshwater fish being significantly (P < 0.05) lower than that of anuran sperm (~4100 seconds). The average velocity of anuran sperm (25 μm/s) was significantly (P < 0.05) lower than that of marine fish (140 μm/s) or freshwater fish (135 μm/s) sperm. The longevity of the sperm of giant salamanders (Cryptobranchoidea) of approximately 600 seconds was greater than that of freshwater fish sperm but much lower than anuran sperm. Our research and information from the literature showed that higher osmolarities promote greater longevity in anuran sperm, and some freshwater fish sperm, and that anuran and cryptobranchid sperm maintained membrane integrity long after the cessation of motility, demonstrating a preferential sharing of energy reserves toward the maintenance of membrane integrity. The maintenance of the membrane integrity of anuran sperm in fresh water for up to 6 hours showed an extremely high osmotic tolerance relative to fish sperm. The very high longevity and osmotic tolerance of anuran sperm and high longevity of cryptobranchid sperm, relative to those of freshwater fish, may reflect the complex fertilization history of amphibian sperm in
Maroto-Morales, A; Ramón, M; García-Álvarez, O; Montoro, V; Soler, A J; Fernández-Santos, M R; Roldan, E R S; Pérez-Guzmán, M D; Garde, J J
Although there is ample evidence for the effects of sperm head shape on sperm function, its impact on fertility has not been explored in detail at the intraspecific level in mammals. Here, we assess the relationship between sperm head shape and male fertility in a large-scale study in Manchega sheep (Ovis aries), which have not undergone any selection for fertility. Semen was collected from 83 mature rams, and before insemination, head shapes were measured for five parameters: area, perimeter, length, width, and p2a (perimeter(2)/2×π×area) using a computer-assisted sperm morphometric analysis. In addition, a cluster analysis using sperm head length and p2a factor was performed to determine sperm subpopulations (SPs) structure. Our results show the existence of four sperm SPs, which present different sperm head phenotype: SP1 (large and round), SP2 (short and elongated), SP3 (shortest and round), and SP4 (large and the most elongated). No relationships were found between males' fertility rates and average values of sperm head dimensions. However, differences in fertility rates between rams were strongly associated to the proportion of spermatozoa in an ejaculate SP with short and elongated heads (P < 0.001). These findings show how the heterogeneity in sperm head shape of the ejaculate has an effect on reproductive success, and highlight the important role of modulation of the ejaculate at the intraspecific level.
Malo, Aurelio F; Garde, J Julián; Soler, Ana J; García, Andrés J; Gomendio, Montserrat; Roldan, Eduardo R S
Male reproductive success is determined by the ability of males to gain sexual access to females and by their ability to fertilize ova. Among polygynous mammals, males differ markedly in their reproductive success, and a great deal of effort has been made to understand how selective forces have shaped traits that enhance male competitiveness both before and after copulation (i.e., sperm competition). However, the possibility that males also may differ in their fertility has been ignored under the assumption that male infertility is rare in natural populations because selection against it is likely to be strong. In the present study, we examined which semen traits correlate with male fertility in natural populations of Iberian red deer (Cervus elaphus hispanicus). We found no trade-offs between semen traits. Our analyses revealed strong associations between sperm production and sperm swimming velocity, sperm motility and proportion of morphologically normal spermatozoa, and sperm viability and acrosome integrity. These last two variables had the lowest coefficients of variation, suggesting that these traits have stabilized at high values and are unlikely to be related to fitness. In a fertility trial, our results show a large degree of variation in male fertility, and differences in fertility were determined mainly by sperm swimming velocity and by the proportion of morphologically normal sperm. We conclude that male fertility varies substantially in natural populations of Iberian red deer and that, when sperm numbers are equal, it is determined mainly by sperm swimming velocity and sperm morphology.
Ostermeier, G.C.; Sargeant, G.A.; Yandell, B.S.; Parrish, J.J.
group had a linear relationship (r .89, P .05) with fertility. To construct a plot of mean sperm shapes, a novel technique to automatically orient and identify the anterior tip of the sperm head was developed. The mean nuclear shape of high-fertility sperm was more elongated and tapered than those of lower fertility. A discriminant function (P .05) was also constructed that separated the 6 bulls into 2 groups based only on the harmonic amplitudes or sperm nuclear shape. The bulls were correctly classified into the 2 fertility groups. A comparison of sperm chromatin structure analysis (SCSA) and harmonic amplitudes found that overall size variance, anterior roundness, and posterior taperedness of sperm nuclei were related to chromatin stability (P .05). Some of the differences observed in sperm nuclear shape between the high- and lower-fertility bulls may be explained by varying levels of chromatin stability. However, sperm nuclear shape appears to contain additional information from chromatin stability alone. In this particular study, with 6 bulls, all with good chromatin quality, sperm nuclear shape was a better predictor of bull fertility.
Al Naib, A; Hanrahan, J P; Lonergan, P; Fair, S
The aim of this study was to investigate the reasons for differences in field fertility of bulls following insemination with frozen-thawed semen. The study was carried out in two separate parts over two years and comparisons were made between 5 high and 4 low fertility Holstein Friesian bulls as determined by their either 90 day non-return rate (Year 1) or calving rate (Year 2). Two high fertility Limousin bulls were included in Year 1 for comparative purposes. The ability of sperm from each bull to penetrate artificial mucus was assessed (Year 1 = 7 replicates; Year 2 = 5 replicates). Glass capillary tubes (2 per bull per replicate) were filled with artificial mucus and incubated with sperm stained in 1% Hoechst 33342 for 30 min at 37 °C. The number of sperm were subsequently counted at 10 mm intervals along the tube between 40 and 80 mm markers. Sperm mitochondrial activity of each bull was assessed by the MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide) assay (4 replicates in each year). Sperm were incubated with MTT for 1 h at 37 °C following which the absorbance of formazan was read using a spectrophotometer. Sperm viability after thawing was assessed for each bull using a live/dead sperm viability kit (Year 1 = 3 replicates; Year 2 = 4 replicates). A minimum of 250 cells were assessed per bull in each replicate and classified as either live or dead. Finally, the ability of sperm to fertilize oocytes in vitro and their ability to develop to blastocyst stage embryos were assessed (5 replicates in each year involving 220 to 306 oocytes per bull). Data transformation to normalize residuals was required for mucus sperm penetration (square root) and IVF (cleavage and blastocyst rate) results (arcsin). The mean number of sperm counted at each 10 mm mark between 40 and 80 mm was higher in the high fertility (56.0; 95% CI 39.5 to 75.3) compared to the low fertility (42.9; 95% CI 29.3 to 59.1) Holstein Friesian bulls but the difference did not
Talarczyk-Desole, Joanna; Kotwicka, Małgorzata; Jendraszak, Magdalena; Pawelczyk, Leszek; Murawski, Marek; Jędrzejczak, Piotr
The aim of this study was to investigate the relationship between apoptotic markers present in human spermatozoa, namely phosphatidylserine translocation (PST) from the inner to the outer layer of the cytomembrane and the active form of caspase-3 (c3) versus the fertilizing potential of male gametes in conventional in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) models. A total of 116 male patients treated with their partners for infertility underwent basic semen analysis and an assessment of the presence of PST and the active c3 in sperm using flow cytometry. Forty patients underwent IVF, group A, while 76 patients underwent ICSI, group B. The fertilizing potential of the gametes was measured as the percentage of oocytes with pronuclei present after either procedure. PST and active c3 were identified in vital gametes, mainly in the midpiece area. Concentration, motility, morphology, and viability of spermatozoa strongly negatively correlated with both markers. In group A, a negative correlation between both markers and the success rate of conventional IVF was observed (r = -0.4, p = 0.04 for PST; r = -0.4, p = 0.02 for active c3, respectively). In group B, the success rate of ICSI did not correlate with either marker (r = -0.2, p = 0.85 for PST and r = 0.1, p = 0.51 for active c3). The two apoptotic markers localized in the sperm midpiece area may affect their function not only by decreasing basic andrologic parameters but also by reducing the probability of conception. Therefore, analysis of PST and active c3 in the sperm of patients undergoing infertility treatment should be recommended.
Bunning, Harriet; Rapkin, James; Belcher, Laurence; Archer, C. Ruth; Jensen, Kim; Hunt, John
It is commonly assumed that because males produce many, tiny sperm, they are cheap to produce. Recent work, however, suggests that sperm production is not cost-free. If sperm are costly to produce, sperm number and/or viability should be influenced by diet, and this has been documented in numerous species. Yet few studies have examined the exact nutrients responsible for mediating these effects. Here, we quantify the effects of protein (P) and carbohydrate (C) intake on sperm number and viability in the cockroach Nauphoeta cinerea, as well as the consequences for male fertility. We found the intake of P and C influenced sperm number, being maximized at a high intake of diets with a P : C ratio of 1 : 2, but not sperm viability. The nutritional landscapes for male fertility and sperm number were closely aligned, suggesting that sperm number is the major determinant of male fertility in N. cinerea. Under dietary choice, males regulate nutrient intake at a P : C ratio of 1 : 4.95, which is midway between the ratios needed to maximize sperm production and pre-copulatory attractiveness in this species. This raises the possibility that males regulate nutrient intake to balance the trade-off between pre- and post-copulatory traits in this species. PMID:25608881
Men, Nguyen Thi; Kikuchi, Kazuhiro; Nakai, Michiko; Fukuda, Atsunori; Tanihara, Fuminori; Noguchi, Junko; Kaneko, Hiroyuki; Linh, Nguyen Viet; Nguyen, Bui Xuan; Nagai, Takashi; Tajima, Atsushi
Freeze-drying (FD) medium containing ethylene glycol-bis(2-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA) is reported to be beneficial for maintenance of sperm DNA integrity after FD. Recently, trehalose has also been reported to have notable ability to stabilize the protein structure and biomembranes of sperm in a dry state. In this study, we examined the effect of a combination of EGTA and different concentrations of trehalose in FD medium on sperm DNA integrity and the in vitro development of IVM porcine oocytes after intracytoplasmic sperm injection (ICSI) using freeze-dried boar sperm. Ejaculated sperm from a boar were suspended in basic FD medium supplemented with 0, 3.75, 7.5, 15, 30, 60, or 90 mM trehalose and freeze-dried. After rehydration, the sperm in all groups were subjected to DNA damage detection using a Halomax kit. It was found that the level of DNA damage in 15-mM group was significantly lower than that in 0-mM group, and no difference was observed between the 15-, 7.5-, and 3.75-mM groups. Moreover, there were no significant differences in the DNA damage level among 0, 3.75 mM, and other groups treated with trehalose. When freeze-dried sperm were used for ICSI, the fertilization rates and blastocyst formation rates (observed at 10 hours and 6 days of IVC after ICSI, respectively) in the 7.5- and 15-mM groups were not different from those in 0-mM group. These results suggest that FD medium supplemented with trehalose at appropriate concentrations improves sperm DNA integrity, but does not improve fertilization and preimplantation embryo development of IVM oocytes following ICSI.
Swann, Karl; Lai, F Anthony
The most fundamental unresolved issue of fertilization is to define how the sperm activates the egg to begin embryo development. Egg activation at fertilization in all species thus far examined is caused by some form of transient increase in the cytoplasmic free Ca(2+) concentration. What has not been clear, however, is precisely how the sperm triggers the large changes in Ca(2+) observed within the egg cytoplasm. Here, we review the studies indicating that the fertilizing sperm stimulates a cytosolic Ca(2+) increase in the egg specifically by delivering a soluble factor that diffuses into the cytosolic space of the egg upon gamete membrane fusion. Evidence is primarily considered in species of eggs where the sperm has been shown to elicit a cytosolic Ca(2+) increase by initiating Ca(2+) release from intracellular Ca(2+) stores. We suggest that our best understanding of these signaling events is in mammals, where the sperm triggers a prolonged series of intracellular Ca(2+) oscillations. The strongest empirical studies to date suggest that mammalian sperm-triggered Ca(2+) oscillations are caused by the introduction of a sperm-specific protein, called phospholipase C-zeta (PLCζ) that generates inositol trisphosphate within the egg. We will discuss the role and mechanism of action of PLCζ in detail at a molecular and cellular level. We will also consider some of the evidence that a soluble sperm protein might be involved in egg activation in nonmammalian species.
Guasti, P N; Monteiro, G A; Maziero, R R D; Carmo, M T; Dell'Aqua, J A; Crespilho, A M; Rifai, E A; Papa, F O
The aims of this study were to determinate whether pentoxifylline (PTX) increases the motion parameters of fresh and frozen-thawed equine epididymal spermatozoa, to evaluate the tyrosine phosphorylation of frozen-thawed epididymal sperm in the presence of PTX and to determine whether the PTX-treatment of stallion epididymal sperm prior to freezing improves the fertility response of mares to a reduced number of spermatozoa per insemination dose. Fifty epididymis were flushed with a skim milk based extender with or without PTX. The pre-treatment with PTX enhanced the sperm motility after being harvested (P<0.05); however the freeze-thaw process did not alter the sperm kinematics between control and treated samples (P>0.05). Plasma membrane integrity did not differ between control and PTX group after recovery and after thawing (P>0.05), as observed in tyrosine phosphorylation, which the PTX treatment did not alter the percentage of tail-associated immunofluorescence of cryopreserved epididymal sperm (P>0.05). For the fertility trial, different insemination groups were tested: 800×10(6) epididymal sperm (C800); 100×10(6) epididymal sperm (C100); 100×10(6) epididymal sperm recovered in an extender containing PTX (PTX100). The conception rates for C800; C100 and PTX100 were 68.7% (11/16); 31.5% (5/16) and 50% (8/16), respectively. The conception rate did not differ among groups (P>0.05), however, a low number of animals was used in this study. A trend toward significance (P=0.07) was observed between C800 and C100 groups. In conclusion, PTX has no deleterious effect on sperm motility, viability and capacitation of cryopreserved stallion epididymal sperm. The conventional artificial insemination with 100×10(6) sperm recovered with PTX ensures acceptable conception rates and maximize the limited number of doses of cryopreserved stallion epididymal sperm.
Parrish, J J; Foote, R H
The number of bovine spermatozoa separated in a swim-up procedure was quantified using an electronic cell counter. In an initial test of the swim-up procedure, non-frozen sperm samples with different ratios of live to dead cells were prepared and tested for the number of spermatozoa counted by the swim-up procedure. In ejaculates from six bulls, the number of spermatozoa swimming up was related to the number of live cells present (R2 = 0.97). Next, sperm quality of frozen-thawed semen immediately after thawing was measured at 37 C by swim-up sperm count, sperm motility, spermatozoa with an intact acrosome and migration in polyacrylamide gel and then compared with the fertility of the semen used for artificial insemination. Twenty-nine ejaculates of frozen-thawed semen from 11 bulls were evaluated. Correlations with fertility were highest on an ejaculate basis for motility (r = 0.41, P = 0.05) and for swim-up sperm count (r = 0.35, P = 0.06). On a bull basis, swim-up sperm count had the highest correlation with fertility (r = 0.59, P = 0.06). In a multiple regression model to predict male fertility that included all described measures of semen quality, a R2 value of 0.69 was obtained. This is the first report showing that the ability of spermatozoa to swim out of a more dense medium (whole milk-glycerol extender) into culture media is quantitatively related to in vivo fertility.
Barraud-Lange, Virginie; Naud-Barriant, Nathalie; Saffar, Line; Gattegno, Liliane; Ducot, Beatrice; Drillet, Anne-Sophie; Bomsel, Morgane; Wolf, Jean-Philippe; Ziyyat, Ahmed
Background Based on inhibition tests, the alpha6beta1 integrin was suggested to be a sperm receptor, but further experiments using gene deletion techniques have shown that neither oocyte alpha6, nor beta1 integrin subunits were essential for mouse fertilization. Results Using Western blot analysis and immunofluorescence, we showed that the mouse sperm expresses the alpha6beta1 integrin. As for oocyte, binding of GoH3 anti-alpha6 antibody to sperm induces a specific inhibition of sperm fertilizing ability. Comparing zona-intact and zona-free eggs in fusion tests, we showed that the removal of the zona pellucida by acid treatment bypasses fertilizing oocyte alpha6beta1 integrin's function in the adhesion/fusion process. Conclusion These findings show that alpha6beta1 integrin is expressed by both gametes and is functional in their membranes interaction. These results and previous reports, about fertilization of alpha6 or beta1 integrin subunits deleted oocytes by wild type sperm, suggest that the presence of alpha6beta1 integrin on one of the two gamete membranes can rescue the fertilization process. This hypothesis is further supported by the exchange of membrane fragments occurring between gametes prior to fusion that we recently reported. PMID:17850654
Ernesto, Juan I.; Weigel Muñoz, Mariana; Battistone, María A.; Vasen, Gustavo; Martínez-López, Pablo; Orta, Gerardo; Figueiras-Fierro, Dulce; De la Vega-Beltran, José L.; Moreno, Ignacio A.; Guidobaldi, Héctor A.; Giojalas, Laura; Darszon, Alberto; Cohen, Débora J.
Ca2+-dependent mechanisms are critical for successful completion of fertilization. Here, we demonstrate that CRISP1, a sperm protein involved in mammalian fertilization, is also present in the female gamete and capable of modulating key sperm Ca2+ channels. Specifically, we show that CRISP1 is expressed by the cumulus cells that surround the egg and that fertilization of cumulus–oocyte complexes from CRISP1 knockout females is impaired because of a failure of sperm to penetrate the cumulus. We provide evidence that CRISP1 stimulates sperm orientation by modulating sperm hyperactivation, a vigorous motility required for penetration of the egg vestments. Moreover, patch clamping of sperm revealed that CRISP1 has the ability to regulate CatSper, the principal sperm Ca2+ channel involved in hyperactivation and essential for fertility. Given the critical role of Ca2+ for sperm motility, we propose a novel CRISP1-mediated fine-tuning mechanism to regulate sperm hyperactivation and orientation for successful penetration of the cumulus during fertilization. PMID:26416967
Chen, S M; Chen, X M; Lu, Y L; Liu, B; Jiang, M; Ma, Y X
Spermatozoa should undergo a series of biochemical modifications in female reproduction tract, which is collectively called sperm capacitation. The capacitated spermatozoa can bind to the egg zona pellucida, resulting in the occurrence of acrosome reaction which enabled spermatozoa penetrate into the egg. The formation of actin plays an important role in these processes. Actin polymerized during sperm capacitation, but the polymers dispersed before acrosome reaction. In this study, we take our focus on actin-binding protein, cofilin. Our results showed that the % and intensity of sperm expressing cofilin in normal sperm were significantly higher than in abnormal sperm, and the sperm expressing cofilin was correlated with sperm quality. Furthermore, treatment with anti-cofilin antibody increased the percentage of sperm capacitation and inhibited progesterone- or A23187- induced acrosome reaction in a dose-dependent manner. The presence of 100 ng/mL anti-cofilin antibodies markedly blocked the sperm penetration of zona-free hamster eggs. Besides, immunofluorescence results revealed that cofilin was colocalized with F-actin in the midpiece of spermatozoa; however, phospho-cofilin was expressed in the tail rather than in the midpiece of spermatozoa, which was not colocalized with F-actin in spermatozoa. Moreover, western blot revealed that phospho-cofilin increased in sperm capacitation, and the total cofilin and cofilin in insoluble fraction increased in acrosome reaction; immunofluorescence results showed that the amount of cofilin in acrosome increased in sperm capacitation. In conclusion, our study revealed that cofilin expression in human sperm is correlated with sperm quality and the alterations of cofilin and phospho-cofilin in fertilization affects sperm capacitation, acrosome reaction, and spermatozoa-oocyte fusion.
Berger, Trish; Conley, Alan J
Increasing sperm production per breeding male has economic significance with increasing use of artificial insemination. Manipulations to increase sperm production in livestock will only be useful if libido and sperm fertilizing capacity are not adversely affected. Reducing endogenous estrogens in the postnatal interval increases the number of Sertoli cells and hence testicular sperm production capacity. These experiments were designed to evaluate the effects of reducing endogenous estrogens on libido and sperm fertilizing capacity. Boars were treated with an aromatase inhibitor, letrozole, to reduce testicular estrogen production between 1 and 6 weeks of age or between 11 and 16 weeks of age, and the littermates to these boars were treated with the canola oil vehicle. Letrozole treatment did not affect time to first mount at 22 weeks of age, regardless of whether the treatment occurred from 1 to 6 weeks of age (118 seconds vs. 233 seconds, SEM = 161 for letrozole-treated and vehicle-treated boars, respectively) or from 11 to 16 weeks of age (107 seconds vs. 67 seconds, SEM = 63 for letrozole-treated and vehicle-treated boars, respectively). Similarly, sperm fertilizing ability and in vivo fertility were equivalent in letrozole-treated boars and their vehicle-treated littermates. Surprisingly, the increase in Sertoli cell numbers observed in the letrozole-treated boars at 20 weeks of age (5.8 vs. 4.3 billion, SEM = 0.5; P < 0.05) was not maintained to 40 weeks of age in their letrozole-treated littermates. Reducing endogenous estrogen production neonatally or prepuberally had no detectable adverse effect on libido or sperm fertilizing capacity.
Zimmerman, Shawn W; Manandhar, Gaurishankar; Yi, Young-Joo; Gupta, Satish K; Sutovsky, Miriam; Odhiambo, John F; Powell, Michael D; Miller, David J; Sutovsky, Peter
Despite decades of research, the mechanism by which the fertilizing spermatozoon penetrates the mammalian vitelline membrane, the zona pellucida (ZP) remains one of the unexplained fundamental events of human/mammalian development. Evidence has been accumulating in support of the 26S proteasome as a candidate for echinoderm, ascidian and mammalian egg coat lysin. Monitoring ZP protein degradation by sperm during fertilization is nearly impossible because those few spermatozoa that penetrate the ZP leave behind a virtually untraceable residue of degraded proteins. We have overcome this hurdle by designing an experimentally consistent in vitro system in which live boar spermatozoa are co-incubated with ZP-proteins (ZPP) solubilized from porcine oocytes. Using this assay, mimicking sperm-egg interactions, we demonstrate that the sperm-borne proteasomes can degrade the sperm receptor protein ZPC. Upon coincubation with motile spermatozoa, the solubilized ZPP, which appear to be ubiquitinated, adhered to sperm acrosomal caps and induced acrosomal exocytosis/formation of the acrosomal shroud. The degradation of the sperm receptor protein ZPC was assessed by Western blotting band-densitometry and proteomics. A nearly identical pattern of sperm receptor degradation, evident already within the first 5 min of coincubation, was observed when the spermatozoa were replaced with the isolated, enzymatically active, sperm-derived proteasomes. ZPC degradation was blocked by proteasomal inhibitors and accelerated by ubiquitin-aldehyde(UBAL), a modified ubiquitin protein that stimulates proteasomal proteolysis. Such a degradation pattern of ZPC is consistent with in vitro fertilization studies, in which proteasomal inhibitors completely blocked fertilization, and UBAL increased fertilization and polyspermy rates. Preincubation of intact zona-enclosed ova with isolated active sperm proteasomes caused digestion, abrasions and loosening of the exposed zonae, and significantly reduced
Matás, C; Sansegundo, M; Ruiz, S; García-Vázquez, F A; Gadea, J; Romar, R; Coy, P
This work was designed to study how this ability is affected by different sperm treatments routinely used for in vitro fertilization (IVF) assay. In this study, boar sperm samples from epididymal or ejaculated origin were processed by three different methods: left unwashed (NW group), washed in Dulbecco's phosphate-buffered saline supplemented with 0.1% BSA (BSA group), and washed on a Percoll(®) gradient (PERCOLL group). After preparation of semen samples, changes in motility patterns were studied by CASA, calcium uptake by spectrofluorimetry, and ROS generation, spontaneous acrosome reaction, and lipid disorder by means of flow cytometry. Finally IVF assays were also performed with the different semen samples and penetrability results evaluated at 2 and 4 h post insemination (hpi). Independently of the sperm treatment, epididymal spermatozoa showed higher values of progressive motility, percentage of live cells with low lipid disorder, and penetration ability at 4 hpi than the corresponding ejaculated spermatozoa. Ejaculated spermatozoa showed higher levels of calcium uptake, ROS generation and percentage of spontaneous acrosome reaction than epididymal sperm. Regarding sperm treatments, PERCOLL group showed the highest values for some motility parameters (linearity of the curvilinear trajectory, straightness, and average path velocity/curvilinear velocity), ROS generation and penetration ability at 2 and 4 hpi; however this same group showed the lowest values for sperm curvilinear velocity and lateral head displacement. From all experimental groups, ejaculated-PERCOLL-treated spermatozoa showed the highest fertilization ability after 2 hpi. Results suggest that capacitation pathways can be regulated by suitable treatments making the ejaculated sperm able to reach capacitation and fertilize oocytes in similar levels than epididymal spermatozoa, although most of the studied capacitation-associated changes do not correlate with this ability.
Stoltz, J A; Neff, B D
The role of sperm number and quality in male competitiveness was investigated using in vitro fertilization experiments with bluegill (Lepomis macrochirus). Bluegill males use one of three mating tactics: 'sneakers', which streak spawn; 'satellites', which mimic females; and 'parentals', which are territorial. The in vitro experiments mimicked natural spawning by incorporating these males' mean proximity to eggs and timing of sperm release. Using a maximum-likelihood algorithm, raffle equations were fit to paternity data, which revealed a strong effect of sperm number on male competitiveness. There was no difference in sperm flagellum length, curvilinear swim speed or path linearity among the three male mating types, and these traits did not explain any additional variation in male competitiveness. It was estimated that, given closer proximity to eggs, satellites need release only 0.34 times as many sperm as parentals to obtain equal paternity. Despite being farther from the eggs and releasing sperm about half a second after parentals, sneakers need only release 0.58 times as many sperm as parentals to obtain equal paternity. Thus, the increased competitiveness of sneakers' sperm must come from a component of sperm quality other than speed or length.
Requena, Gustavo S; Alonzo, Suzanne H
Sperm competition theory has traditionally focused on how male allocation responds to female promiscuity, when males compete to fertilize a single clutch of eggs. Here, we develop a model to ask how female sperm use and storage across consecutive reproductive events affect male ejaculate allocation and patterns of mating and paternity. In our model, sperm use (a single parameter under female control) is the main determinant of sperm competition, which alters the effect of female promiscuity on male success and, ultimately, male reproductive allocation. Our theory reproduces the general pattern predicted by existing theory that increased sperm competition favors increased allocation to ejaculates. However, our model predicts a negative correlation between male ejaculate allocation and female promiscuity, challenging the generality of a prevailing expectation of sperm competition theory. Early models assumed that the energetic costs of precopulatory competition and the level of sperm competition are both determined by female promiscuity, which leads to an assumed covariation between these two processes. By modeling precopulatory costs and sperm competition independently, our theoretical framework allows us to examine how male allocation should respond independently to variation in sperm competition and energetic trade-offs in mating systems that have been overlooked in the past.
Tash, J. S.; Kim, S.; Schuber, M.; Seibt, D.; Kinsey, W. H.
Sperm and other flagellates swim faster in microgravity (microG) than in 1 G, raising the question of whether fertilization is altered under conditions of space travel. Such alterations have implications for reproduction of plant and animal food and for long-term space habitation by man. We previously demonstrated that microG accelerates protein phosphorylation during initiation of sperm motility but delays the sperm response to the egg chemotactic factor, speract. Thus sperm are sensitive to changes in gravitational force. New experiments using the NiZeMi centrifugal microscope examined whether low hypergravity (hyperG) causes effects opposite to microG on sperm motility, signal transduction, and fertilization. Sperm % motility and straight-line velocity were significantly inhibited by as little as 1.3 G. The phosphorylation states of FP130, an axonemal phosphoprotein, and FP160, a cAMP-dependent salt-extractable flagellar protein, both coupled to motility activation, showed a more rapid decline in hyperG. Most critically, hyperG caused an approximately 50% reduction in both the rate of sperm-egg binding and fertilization. The similar extent of inhibition of both fertilization parameters in hyperG suggests that the primary effect is on sperm rather than eggs. These results not only support our earlier microG data demonstrating that sperm are sensitive to small changes in gravitational forces but more importantly now show that this sensitivity affects the ability of sperm to fertilize eggs. Thus, more detailed studies on the impact of space flight on development should include studies of sperm function and fertilization.
Klinefelter, G R; Laskey, J W; Ferrell, J; Suarez, J D; Roberts, N L
In a previous study, we found that ethane dimethanesulphonate (EDS) compromised the fertilizing ability of proximal cauda epididymal sperm from the rat within 4 days of exposure, an effect that persisted in castrated, testosterone (T)-implanted animals, establishing direct action on the epididymis. This EDS-induced reduction in fertilizing ability was highly correlated with a quantitative decrease in specific sperm protein. Here we sought to determine whether the fertility of proximal cauda epididymal sperm recovered from animals exposed to a variety of male reproductive toxicants could be predicted by assessing quantitative changes in specific sperm protein(s), or whether more common endpoints (e.g., sperm motility, sperm morphology, serum and epididymal tissue T, cauda epididymal sperm reserves) also are required to predict fertility. Intact adult male rats were dosed with EDS (25 or 50 mg/kg), chloroethylmethanesulphonate (CEMS; 12.5 or 18.75 mg/kg), or epichlorohydrin (EPI; 3 or 6 mg/kg) daily for 4 days. Castrated, T-implanted rats were dosed with hydroxyflutamide (HFLUT; 12.5 or 25 mg/kg) daily for 5 days. On day 5, proximal cauda epididymal sperm were inseminated in utero into receptive, cervically stimulated adult females, and on day 9, fertility (implants/corpora lutea) was assessed. Fertility-was decreased by the higher dose of each toxicant (P < 0.05) and also by the lower dose of EPI and HFLUT. Likewise, an acidic 22 kDa sperm protein (SP22) was decreased quantitatively (P < 0.05) in silver-stained two-dimensional gels by the higher dose of each toxicant as well as by the lower dose of EPI and HFLUT. Although sperm motility and serum T were altered by specific exposures, these endpoints were not useful in predicting fertility. In contrast, SP22 was highly correlated (P < 0.0001; r2 = 0.83) with fertility. Indeed, the amount of SP22 correctly predicted 90% and 94% of the fertile (> 50% fertility) and subfertile (< 50 fertility) animals, respectively
del Olmo, D; Parrilla, I; Gil, M A; Maside, C; Tarantini, T; Angel, M A; Roca, J; Martinez, E A; Vazquez, J M
The objective of this study was to develop an adequate sperm handling protocol in order to obtain a sex-sorted sperm population with an optimal fertilizing ability. For this purpose, different aspects of the sorting procedure were examined. The effects of the high dilution rates (experiment 1), type of collection medium used (experiment 2), and sheath fluid composition (experiment 3) on sorted boar sperm quality and function were evaluated. Sperm quality was assessed by motility and viability tests, whereas sperm function was evaluated by an in vitro fertilization assay which determined the penetration and polyspermy rates as well as the mean number of sperm penetrating each oocyte. In experiment 1, the results obtained indicated that the high dilution rates did not cause a decrease either in the sperm quality parameters evaluated or the in vitro fertilization ability of spermatozoa. In experiment 2, although sperm quality was not affected, fertilizing ability was compromised after sorting, regardless of the collection medium that was used. In the experiment 3, all groups displayed adequate sperm quality values, but higher in vitro fertility parameters were obtained for spermatozoa sorted in presence of EDTA in the sheath fluid and egg yolk (EY) in the collection media when compared with those sorted in absence of these protective agents. No differences in penetration rates between unsorted highly diluted (control) and sorted sperm in the presence of EDTA and EY were observed. In conclusion, fertilizing ability was compromised in sex-sorted sperm. The addition of EDTA to sheath fluid and EY to collection medium improved boar sperm fertilizing ability, and both agents should be included as essential media components in future studies.
Pina-Guzman, Belem; Sanchez-Gutierrez, M.; Marchetti, Francesco; Hernandez-Ochoa, I.; Solis-Heredia, M.J .; Quintanilla-Vega, B.
Paternal germline exposure to organophosphorous pesticides (OP) has been associated with reproductive failures and adverse effects in the offspring. Methyl parathion (Me-Pa), a worldwide-used OP, has reproductive adverse effects and is genotoxic to sperm. Oxidative damage has been involved in the genotoxic and reproductive effects of OP. The purpose of this study was to determine the effects of Me-Pa on spermatozoa function and ability to fertilize. Male mice were exposed to Me-Pa (20 mg/kg bw, i.p.) and spermatozoa from epididymis-vas deferens were collected at 7 or 28 days post-treatment (dpt) to assess the effects on maturing spermatozoa and spermatocytes, respectively. DNA damage was evaluated by nick translation (NT-positive cells) and SCSA (percentDFI); lipoperoxidation (LPO) by malondialdehyde production; sperm function by spontaneous- and induced-acrosome reactions (AR); mitochondrial membrane potential (MMP) by using the JC-1 flurochrome; and, fertilization ability by an in vitro assay and in vivo mating. Results showed alterations in DNA integrity (percentDFI and NT-positive cells) at 7 and 28 dpt, in addition to decreased sperm quality and a decrease in induced-AR; reduced MMP and LPO was observed only at 7 dpt. We found negative correlations between LPO and all sperm alterations. Altered sperm functional parameters were associated with reduced fertilization rates at both times, evaluated either in vitro or in vivo. These results show that Me-Pa exposure of maturing spermatozoa and spermatocytes affects many sperm functional parameters that result in a decreased fertilizing capacity. Oxidative stress seems to be a likely mechanism ofthe detrimental effects of Me-Pa in male germ cells.
Piña-Guzmán, B; Sánchez-Gutiérrez, M; Marchetti, F; Hernández-Ochoa, I; Solís-Heredia, M J; Quintanilla-Vega, B
Paternal germline exposure to organophosphorous pesticides (OP) has been associated with reproductive failures and adverse effects in the offspring. Methyl-parathion (Me-Pa), a worldwide-used OP, has reproductive adverse effects and is genotoxic to sperm, possibly via oxidative damage. This study investigated the stages of spermatogenesis susceptible to be targeted by Me-Pa exposure that impact on spermatozoa function and their ability to fertilize. Male mice were exposed to Me-Pa (20 mg/kg bw, i.p.) and spermatozoa from epididymis-vas deferens were collected at 7 or 28 days post-treatment (dpt) to assess the effects on maturing spermatozoa and spermatocytes, respectively. Spermatozoa were examined for DNA damage by nick translation (NT-positive cells) and SCSA (%DFI), lipoperoxidation (LPO) by malondialdehyde production, sperm function by spontaneous- and induced-acrosome reactions (AR), mitochondrial membrane potential (MMP) by using the JC-1 fluorochrome, and fertilization ability by an in vitro assay and in vivo mating. Alterations on DNA integrity (%DFI and NT-positive cells) in spermatozoa collected at 7 and 28 dpt, and decreases in sperm quality and induced-AR were observed; reduced MMP and LPO were observed at 7 dpt only. Negative correlations between LPO and sperm alterations were found. Altered sperm functional parameters evaluated either in vitro or in vivo were associated with reduced fertilization rates at both times. These results show that Me-Pa exposure of maturing spermatozoa and spermatocytes affects many sperm functional parameters that result in a decreased fertilizing capacity. Oxidative stress seems to be a likely mechanism of the detrimental effects of Me-Pa exposure in male germ cells.
Michalczyk, Łukasz; Martin, Oliver Y.; Millard, Anna L.; Emerson, Brent C.; Gage, Matthew J. G.
As populations decline to levels where reproduction among close genetic relatives becomes more probable, subsequent increases in homozygous recessive deleterious expression and/or loss of heterozygote advantage can lead to inbreeding depression. Here, we measure how inbreeding across replicate lines of the flour beetle Tribolium castaneum impacts on male reproductive fitness in the absence or presence of male–male competition. Effects on male evolution from mating pattern were removed by enforcing monogamous mating throughout. After inbreeding across eight generations, we found that male fertility in the absence of competition was unaffected. However, we found significant inbreeding depression of sperm competitiveness: non-inbred males won 57 per cent of fertilizations in competition, while inbred equivalents only sired 42 per cent. We also found that the P2 ‘offence’ role in sperm competition was significantly more depressed under inbreeding than sperm ‘defence’ (P1). Mating behaviour did not explain these differences, and there was no difference in the viability of offspring sired by inbred or non-inbred males. Sperm length variation was significantly greater in the ejaculates of inbred males. Our results show that male ability to achieve normal fertilization success was not depressed under strong inbreeding, but that inbreeding depression in these traits occurred when conditions of sperm competition were generated. PMID:20554548
Michalczyk, Lukasz; Martin, Oliver Y; Millard, Anna L; Emerson, Brent C; Gage, Matthew J G
As populations decline to levels where reproduction among close genetic relatives becomes more probable, subsequent increases in homozygous recessive deleterious expression and/or loss of heterozygote advantage can lead to inbreeding depression. Here, we measure how inbreeding across replicate lines of the flour beetle Tribolium castaneum impacts on male reproductive fitness in the absence or presence of male-male competition. Effects on male evolution from mating pattern were removed by enforcing monogamous mating throughout. After inbreeding across eight generations, we found that male fertility in the absence of competition was unaffected. However, we found significant inbreeding depression of sperm competitiveness: non-inbred males won 57 per cent of fertilizations in competition, while inbred equivalents only sired 42 per cent. We also found that the P(2) 'offence' role in sperm competition was significantly more depressed under inbreeding than sperm 'defence' (P(1)). Mating behaviour did not explain these differences, and there was no difference in the viability of offspring sired by inbred or non-inbred males. Sperm length variation was significantly greater in the ejaculates of inbred males. Our results show that male ability to achieve normal fertilization success was not depressed under strong inbreeding, but that inbreeding depression in these traits occurred when conditions of sperm competition were generated.
Asturiano, J F; Sørensen, S R; Pérez, L; Lauesen, P; Tomkiewicz, J
Sperm cryopreservation is a useful tool in captive fish reproduction management, that is to synchronize gamete production, especially in the case of species as the European eel, where the time of female spawning readiness is unpredictable. Several protocols to cryopreserve sperm of this species have been described, but until recently fertilization trials were not feasible. This study evaluated the effect of cold storage of diluted sperm prior to fertilizations and tested whether a previously defined protocol for European eel sperm cryopreservation can be successfully applied in fertilization trials to produce viable offspring. In our experiment, the sperm motility was evaluated after the extraction and the best samples were selected and pooled. Until stripping of eggs and fertilization, diluted sperm samples were maintained at either 4 or 20°C, or cryopreserved, following existing protocols. Fertilization of two egg batches was attempted. Diluted sperm caused a similar percentage of fertilized eggs and a similar number of embryos and larvae, independently of storage temperature (4 or 20°C). The cryopreserved sperm resulted in a lower percentage of fertilized eggs, but embryos developed and a few larvae ('cryolarvae') were obtained 55 h after fertilization in one of the two egg batches. This result evidences that the tested cryopreservation protocol is applicable for eel reproduction management, although improvements will be required to enhance fertilization success.
Allouche, Lynda; Madani, Toufik; Mechmeche, Mohamed; Clement, Laetitia; Bouchemal, Allaoua
Background Sperm selection method is usually used to collect these cells for in vitro-assisted reproduction. Few studies reported the relationship of in vivo fertility and semen parameters after sperm selection; hence, the present study attempted to assess different semen parameters after post-thaw or sperm selection, using density gradient separation BoviPure®, to predict in vivo fertility. Materials and Methods In this experimental study, frozen semen quality of four Montbeliarde bulls were assessed after post-thaw (PT) or after sperm selection (SSp), using density gradient separation BoviPure®, to predict the fertility rate in vivo. In addition to PT or SSp, semen was examined for concentration, motility, morphology abnormalities, viability, acrosome and plasma membrane integrities. Fertility was measured as non-return rates within 56 days after the first insemination (NRR) or as corrected NRR, expressed as CNRR, to the factors influencing fertility using linear mixed model. Non-parametric Kruskal-Wallis test was performed to compare semen parameter variables. Fertility rates were compared using Chi-square test. Pearson correlation analysis was used to test the relationship between CNRR and semen parameters. Data was analysed using SPSS package program, version 21.0. Results Most of the examined bulls exhibited a high fertility rate (3/4 bulls, 62.1- 81.8% for NRR or 67.2-98.5% for CNRR). Fertility rate, expressed as CNRR, was significantly related to semen parameters after SSp, but not after PT. Thus, CNRR was increased with decrease of total motility, progressive spermatozoa and abaxial implantation frequencies after SSp (r=-0.999, P=0.001; r=-0.990, P=0.010; r=-0.988, P= 0.012, respectively); while, CNRR was decreased with decrease of SSp immotile spermatozoa (r=+0.995, P=0.005), underlying that maximal limit of determined immotile spermatozoa is 47%. Conclusion High frequencies of total and progressive motility spermatozoa, and abaxial implantation in
Merchant, Rubina; Gandhi, Goral; Allahbadia, Gautam N.
Progress in the field of assisted reproduction, and particularly micromanipulation, now heralds a new era in the management of severe male factor infertility, not amenable to medical or surgical correction. By overcoming natural barriers to conception, in vitro fertilization and embryo transfer (IVF-ET), subzonal sperm insemination, partial zona dissection, and intracytoplasmatic injection of sperm (ICSI) now offer couples considered irreversibly infertile, the option of parenting a genetically related child. However, unlike IVF, which necessitates an optimal sperm number and function to successfully complete the sequence of events leading to fertilization, micromanipulation techniques, such as ICSI, involving the direct injection of a spermatozoon into the oocyte, obviate all these requirements and may be used to alleviate severe male factor infertility due to the lack of sperm in the ejaculate due to severely impaired spermatogenesis (non-obstructive azoospermia) or non-reconstructable reproductive tract obstruction (obstructive azoospermia). ICSI may be performed with fresh or cryopreserved ejaculate sperm where available, microsurgically extracted epididymal or testicular sperm with satisfactory fertilization, clinical pregnancy, and ongoing pregnancy rates. However, despite a lack of consensus regarding the genetic implications of ICSI or the application and efficacy of preimplantation genetic diagnosis prior to assisted reproductive technology (ART), the widespread use of ICSI, increasing evidence of the involvement of genetic factors in male infertility and the potential risk of transmission of genetic disorders to the offspring, generate major concerns with regard to the safety of the technique, necessitating a thorough genetic evaluation of the couple, classification of infertility and adequate counseling of the implications and associated risks prior to embarking on the procedure. The objective of this review is to highlight the indications, advantages
Yi, Young-Joo; Park, Chang-Sik; Kim, Eui-Sook; Song, Eun-Sook; Jeong, Ji-Hyeon; Sutovsky, Peter
Extracellular ATP has been implicated in a number of cellular events, including mammalian sperm function. The complement of ATP-dependent sperm proteins includes six subunits of the 26S proteasome, a multi-subunit protease specific to ubiquitinated substrate-proteins. Proteolysis of ubiquitinated proteins by the 26S proteasome is necessary for the success of mammalian fertilization, including but not limited to acrosomal exocytosis (AE) and sperm-zona pellucida (ZP) penetration. The 26S proteasome is uniquely present on the sperm acrosomal surface during mammalian, ascidian, and invertebrate fertilization. The proteasome is a multi-subunit protease complex of approximately 2 MDa composed of the 19S regulatory complex and a 20S proteolytic core. Integrity of the 19S complex is maintained by six 19S ATPase subunits (PSMC1 through PSMC6). Consequently, we hypothesized that fertilization will be blocked by the depletion of sperm-surface associated ATP (ssATP). Depletion of ssATP by the Solanum tuberosum apyrase, a 49 kDa, non-cell permeant enzyme, significantly reduced the ATP content measured by an adapted luminescence-ATP assay from which all permeabilizing agents were excluded. Addition of active apyrase to porcine in vitro fertilization (IVF) medium caused a concentration dependent reduction in the overall fertilization rate. No such outcomes were observed in control groups using heat-inactivated apyrase. Apyrase treatment altered the band pattern of 19S ATPase subunits PSMC1 (Rpt2) and PSMC4 (Rpt3) in Western blotting, suggesting that it had an effect on the integrity of the sperm proteasomal 19S complex. Apyrase only altered the proteasomal core activities slightly, since these activities are not directly dependent on external ATP. In contrast, sperm treatment with MG132, a specific inhibitor of the proteasomal core chymotrypsin-like activity, inhibited the target proteolytic activity, but also induced a compensatory elevation in proteasomal peptidyl
Li, Fang-Fang; Wang, Xiao-Ying; Zhou, Shu-Min; You, Fan
Due to the low effectiveness of traditional assisted reproductive technology (ART), new technological possibilities are constantly explored. Lots of studies have demonstrated the potential of microfluidics to revolutionize the fundamental processes of in vitro fertilization (IVF). With the advantages of high efficiency, short time, harmless collection, real-time observation of separation, similar microenvironment, and automation, the application of microfluidics in sperm isolation and IVF has shown an evident superiority over the conventional approaches and provided a new platform for ART. This review highlights the application of various microfluidic techniques in sperm motility assessment and isolation, sperm chemotaxis assay, IVF, sperm concentration, and sperm separation and enrichment in recent years. It also briefly introduces the basic principles, structural design, and operation processes of the microfluidic platform, focusing on the advantages and disadvantages of each method and the potential of their clinical application. Obviously, there are still some challenges to the application of microfluidics in ART. However, it is believed that the development of this new technology would be toward a highly integrated application of several steps in one single device, known as IVF-lab-on-a-chip.
Abstract We investigated the effects of two trout sperm activation solutions on sperm physiology and membrane organization prior to and following cryopreservation using flow cytometry and investigated their impact on in vitro fertility. Cryopreservation caused greater phospholipid disorder (high pl...
Koch, R A; Lambert, C C
This review discusses the ultrastructure of sperm with reference to their development, the surface morphology of the egg, and the processes of sperm binding and penetration during fertilization. These topics are treated for selected invertebrates and lower vertebrates which live in aquatic environments and fertilize their eggs externally. Specifically, sperm eggs from cnidarians, echinoderms, decapod crustaceans, ascidians, lampreys, bony fishes, and amphibians are discussed. Sperm from the majority of these groups exhibit the classical head-midregion-tail configuration characteristic of primitive sperm. Specific variations within this general morphology have been described. The notable exceptions to the primitive-sperm paradigm are the sperm of decapod crustaceans and amphibians. Eggs from all of the animals considered are covered by complex vitelline envelopes except those of cnidarians. In general, the ultrastructural analysis of these egg envelopes shows that they are composed of fibrous subunits. Sperm bind to the vitelline envelope and then penetrate through it to fertilize the egg in all groups reviewed except fishes. In sperm ultrastructure which occur during penetration of the egg envelopes in both flagellated and non-flagellated sperm. These changes, which involve membrane fusion and reorganization as well as movement of membranous organelles, aid the sperm in reaching the actual site of gamete fusion.
Nynca, J; Dietrich, G J; Dobosz, S; Zalewski, T; Ciereszko, A
The aim of this study was to test the influence of postthaw storage time on sperm motility parameters of brook trout (n = 9). Furthermore, we examined the effect of sperm-to-egg ratios of 300,000:1 and 600,000:1 on fertility of postthaw, cryopreserved, brook trout sperm. The application of a cryopreservation procedure produced very high postthaw sperm motility (56.8 ± 4.0%). The cryopreserved sperm of brook trout could be stored up to 60 minutes without loss of the percentage of sperm motility (52.0 ± 9.0%). The fertilization capacity of brook trout postthaw sperm was comparable with the fertilization rate of fresh semen at a sperm-to-egg ratio as low as 300,000:1 (42.4 ± 14.0% and 36.5 ± 11.0% for eyed and hatched stages, respectively). The possibility of postthaw semen storage for the prolonged time and the obtainment of high fertilization rate at low sperm-to-egg ratio can lead to the significant improvement of brook trout semen cryopreservation procedure.
Simon, Luke; Lewis, Sheena E M
Sperm progressive motility has been reported to be one of the key factors influencing in vitro fertilization rates. However, recent studies have shown that sperm DNA fragmentation is a more robust predictor of assisted reproductive outcomes including reduced fertilization rates, embryo quality, and pregnancy rates. This study aimed to compare the usefulness of sperm progressive motility and DNA damage as predictive tools of in vitro fertilization rates. Here, 136 couples provided 1,767 eggs with an overall fertilization rate of 64.2%. The fertilization rate in vitro correlated with both sperm progressive motility (r² = 0.236; P = 0.002) and DNA fragmentation (r² = -0.318; P < 0.001). The relative risk of a poor fertilization rate was 9.5 times higher in sperm of men with high DNA fragmentation (>40%) compared with 2.6 times in sperm with poor motility (<40%). Further, sperm DNA fragmentation gave a higher specificity (93.3%) in predicting the fertilization rate than progressive motility (77.8%). Finally, the odds ratio to determine fertilization rate (>70%) was 4.81 (1.89-12.65) using progressive motility compared with 24.18 (5.21-154.51) using DNA fragmentation. This study shows that fertilization rates are directly dependent upon both sperm progressive motility and DNA fragmentation, but sperm DNA fragmentation is a much stronger test.
Roth, T L; Weiss, R B; Buff, J L; Bush, L M; Wildt, D E; Bush, M
Scimitar-horned oryx sperm function was studied using protocols developed for domestic cattle. Objectives were to assess sperm 1) viability and motility in vitro over time, 2) capacitation in heparin- or calcium-supplemented medium, and 3) function in an in vitro fertilization system using heterologous (domestic cow) oocytes. Seminal aliquots were washed, and sperm were resuspended in 1) Talp with 5% fetal calf serum (TALP), 2) TALP + 10 microM heparin, 3) TALP + 20 microM heparin, and 4) TALP + 10 mM CaCl. At 0, 3, and 6 h, aliquots were evaluated for sperm motility, viability (using Hoechst 33258), and ability to acrosome-react when exposed to lysophosphatidylcholine (LC). Sperm function was assessed by evaluating fertilization and embryo development after coculture of in vitro-matured domestic cow oocytes with oryx sperm. Overall mean percentages of motile and viable sperm remained high at 6 h (> 60% and > 70%, respectively). Fewer (p < 0.05) sperm incubated in TALP + 10 microM heparin for 6 h contained intact acrosomes after exposure to LC, but there were no differences between LC and control samples after incubation in TALP without heparin. LC-treated sperm in TALP + 10 mM CaCl contained fewer (p < 0.05) intact acrosomes at 3 and 6 h (52.6% and 31.2%, respectively) than paired controls (83.6% and 70.0%, respectively). Oryx sperm from all males were capable of fertilizing cow oocytes (range 17 of 26 [65.4%] to 25 of 26 [96.2%]). Of the 55 2-cell embryos produced, 34 (61.8%) developed to > or = 8 cells. Of the 24 uncleaved oocytes, 7 (29.2%) were polyspermic. These data demonstrate that processed sperm from the endangered scimitar-horned oryx remain vigorous in vitro for at least 6 h. Capacitation can be induced using cattle sperm-processing techniques, with sperm appearing most responsive to elevated CaCl concentrations. Most interesting was the successful production and development of hybrid embryos after coincubation of oryx sperm with cow oocytes, suggesting
Bronson, Richard A; Bronson, Susan K; Oula, Lucila D
A body of evidence indicates that morphologically abnormal human spermatozoa may exhibit impaired ability to fertilize. Yet teratospermia has widely varying etiologies, including associations with varicoceles, following fever, cigarette smoking, and exposure to polychlorinated biphenyls. Abnormalities of sperm shape in mice have also been shown to be associated with autosomal gene mutations. These varying causes of teratospermia could have different molecular consequences reflected in altered sperm function. We studied the ability of morphologically abnormal human sperm to penetrate zona-free hamster eggs as a measure of their ability to undergo an acrosome reaction and gamete membrane fusion. Motile sperm from ejaculates containing 15% normal sperm or less, as judged by World Health Organization (1999) criteria, were recovered by ISolate density centrifugation and capacitated by overnight incubation. Zona-free hamster eggs were inseminated with 1 x 10(6) motile capacitated cells and scored for sperm penetration after 3 hours of coincubation. A significant trend was found between the percent of abnormal spermatozoa within the ejaculate and impaired egg-penetrating ability, reflected in the percent of eggs penetrated, the number of penetrating sperm per egg, and the number of sperm adherent to the oolemma. Because only acrosome-reacted human spermatozoa adhere to the oolemma, these results support the notion that abnormally shaped sperm may exhibit an impaired ability to undergo an acrosome reaction. A correlation was also noted between the loss of motility of sperm following overnight incubation and impairment of their ability to undergo gamete membrane fusion. These results confirm prior findings at the level of the zona pellucida that abnormally shaped sperm exhibit functional abnormalities. However, a wide variation was observed between men in the behavior of such sperm, including occasionally high rates of egg penetration. These observations suggest that
Yamaguchi, Ryo; Fujihara, Yoshitaka; Ikawa, Masahito; Okabe, Masaru
Eight kinds of gene-disrupted mice (Clgn, Calr3, Pdilt, Tpst2, Ace, Adam1a, Adam2, and Adam3) show impaired sperm transition into the oviducts and defective sperm binding to the zona pellucida. All of these knockout strains are reported to lack or show aberrant expression of a disintegrin and metallopeptidase domain 3 (ADAM3) on the sperm membrane. We performed proteomic analyses of the proteins of these infertile spermatozoa to clarify whether the abnormal function is caused exclusively by a deficiency in ADAM3 expression. Two proteins, named PMIS1 and PMIS2, were missing in spermatozoa from Clgn-disrupted mice. To study their roles, we generated two gene-disrupted mouse lines. Pmis1-knockout mice were fertile, but Pmis2-knockout males were sterile because of a failure of sperm transport into the oviducts. Pmis2-deficient spermatozoa also failed to bind to the zona pellucida. However, they showed normal fertilizing ability when eggs surrounded with cumulus cells were used for in vitro fertilization. Further analysis revealed that these spermatozoa lacked the ADAM3 protein, but the amount of PMIS2 was also severely reduced in Adam3-deficient spermatozoa. These results suggest that PMIS2 might function both as the ultimate factor regulating sperm transport into the oviducts and in modulating sperm-zona binding.
Tirmarche, Samantha; Kimura, Shuhei; Dubruille, Raphaëlle; Horard, Béatrice; Loppin, Benjamin
In most animals, the extreme compaction of sperm DNA is achieved after the massive replacement of histones with sperm nuclear basic proteins (SNBPs), such as protamines. In some species, the ultracompact sperm chromatin is stabilized by a network of disulfide bonds connecting cysteine residues present in SNBPs. Studies in mammals have established that the reduction of these disulfide crosslinks at fertilization is required for sperm nuclear decondensation and the formation of the male pronucleus. Here, we show that the Drosophila maternal thioredoxin Deadhead (DHD) is specifically required to unlock sperm chromatin at fertilization. In dhd mutant eggs, the sperm nucleus fails to decondense and the replacement of SNBPs with maternally-provided histones is severely delayed, thus preventing the participation of paternal chromosomes in embryo development. We demonstrate that DHD localizes to the sperm nucleus to reduce its disulfide targets and is then rapidly degraded after fertilization. PMID:27876811
Nozawa, Yoko; Isomura, Naoko; Fukami, Hironobu
This study presents new information on the influence of sperm dilution on the fertilization rates of eight broadcast-spawning scleractinian coral species [three Acropora species and five merulinid species (three genera)]. The presented information nearly doubled the existing information, now totaling 17 species comprising eight acroporid species and nine merulinid species. No obvious differences in the fertilization rates were observed at the family and genus levels; furthermore, the fertilization curve estimated uniquely for Favites pentagona exhibited a strong sigmoid shape, indicating the existence of species-specific variation. In addition, a general fertilization response against sperm dilution was observed for the first time in broadcast-spawning scleractinian corals. The fertilization rate peaked (>75 %) at a sperm concentration of approximately 106 sperm mL-1 (optimal concentration) and rapidly declined to <50 % at a concentration of 104 sperm mL-1. The influence of gamete contact time (10, 30, and 60 min) on fertilization rates was also examined in two Acropora and four merulinid species, at the optimal sperm concentration. No influence of gamete contact time on fertilization rates was observed in two of the examined species ( Acropora papillare and Platygyra ryukyuensis), whereas reduced fertilization rates occurred mostly in the 10-min treatment for the other species. These results suggested that broadcast-spawning scleractinian corals can rapidly fertilize, indicating that these corals have a fair chance of achieving high fertilization success in the field under optimal conditions. The sperm concentration values (e.g., 104 sperm mL-1, indicating <50 % fertilization rates) may be useful in estimating the success of in situ fertilization of broadcast-spawning scleractinian corals, particularly in degraded, low-density populations where the degree of fertilization success is of management concern. Information on the fertilization ecology of scleractinian
Bishop, J. D. D.
In broadcast-spawning marine animals, rapid dilution and short lifespan of sperm following release may impose severely localized patterns of mating. Partial or total failure of external fertilization due to sperm limitation appears commonplace. However, it is not clear to what extent the restrictive kinetics of fertilization in water also constrain mating in animals that release sperm but retain their eggs for fertilization.
The compound ascidian Diplosoma listerianum liberates sperm that are dispersed to other colonies and taken in prior to internal cross-fertilization. The fertile lifespan of sperm was found to be long (half-life ca. 8 hours), and a substantial number of fertilizations occurred with 24-hour-old sperm. Fertilizations were obtained from sperm concentrations that would typically produce little or no external fertilization. In a separate experiment, a very small piece of D. listerianum (dry weight less than 2 mg) sired abundant progeny throughout a 3840 l tank. Paternity of progeny in these experiments was confirmed by molecular markers. The same markers were used to extend, to over seven weeks, the known maximum period of storage of exogenous sperm prior to fertilization in this species.
The production of only a few thousand sperm at a time by each zooid, poor synchronization of release between zooids, and the existence of many well-spaced exhalant openings in large colonies suggest that D. listerianum is incapable of generating a dense plume of sperm, even close to the source. It is suggested that, unlike external fertilization, successful internal cross-fertilization in D. listerianum is not dependent upon the interception of a dense cloud of gametes just released by a near neighbour. It seems instead that dilute, long-lived sperm can be extracted efficiently from seawater by this suspension feeder, potentially over a period of time. This capability, and other features of the life history, make it unlikely that sperm limitation is an acute
Using cryopreserved boar sperm rather than liquid semen for in vitro fertilization (IVF) allows improved IVF consistency. However, cryopreservation of boar sperm results in reduced post-thaw motility, fertilization and embryo development. Boars are often screened on an individual basis prior to use ...
Gadella, B M; Boerke, A
The fusion of a sperm with an oocyte to form new life is a highly regulated event. The activation-also termed capacitation-of the sperm cell is one of the key preparative steps required for this process. Ejaculated sperm has to make a journey through the female uterus and oviduct before it can approach the oocyte. The oocyte at that moment also has become prepared to facilitate monospermic fertilization and block immediately thereafter the chance for polyspermic fertilization. Interestingly, ejaculated sperm is not properly capacitated and consequently is not yet able to fertilize the oocyte. During the capacitation process, the formation of competent lipid-protein domains on the sperm head enables sperm-cumulus and zona pellucida interactions. This sperm binding allows the onset for a cascade reaction ultimately resulting in oocyte-sperm fusion. Many different lipids and proteins from the sperm surface are involved in this process. Sperm surface processing already starts when sperm are liberated from the seminiferous tubules and is followed by epididymal maturation where the sperm cell surface is modified and loaded with proteins to ensure it is prepared for its fertilization task. Although cauda epididymal sperm can fertilize the oocyte IVF, they are coated with so-called decapacitation factors during ejaculation. The seminal plasma-induced stabilization of the sperm surface permits the sperm transit through the cervix and uterus but prevents sperm capacitation and thus inhibits fertilization. For IVF purposes, sperm are washed out of seminal plasma and activated to get rid of decapacitation factors. Only after capacitation, the sperm can fertilize the oocyte. In recent years, IVF has become a widely used tool to achieve successful fertilization in both the veterinary field and human medicine. Although IVF procedures are very successful, scientific knowledge is still far from complete when identifying all the molecular players and processes during the first
Roh, Jaesook; Lim, Young-Su; Seo, Min-Young; Choi, Yuri; Ryu, Jae-Sook
Trichomonas vaginalis infection is one of the most prevalent sexually transmitted infections in humans and is now recognized as an important cause of infertility in men. There is little information about the effect of extracellular polymeric substances (EPS) from T. vaginalis on sperm, but previous reports do not provide a conclusive description of the functional integrity of the sperm. To investigate the impact of EPS on the fertilizing capacity of sperm, we assessed sperm motility, acrosomal status, hypo-osmotic swelling, and in vitrofertilization rate after incubating the sperm with EPS in vitrousing mice. The incubation of sperm with EPS significantly decreased sperm motility, viability, and functional integrity in a concentration and time-dependent manner. These effects on sperm quality also resulted in a decreased fertilization rate in vitro. This is the first report that demonstrates the direct negative impact of the EPS of T. vaginalis on the fertilization rate of sperm in vitro. However, further study should be performed using human sperm to determine if EPS has similar negative impact on human sperm fertilizing capacity in vitro.
Sessions-Bresnahan, D R; Graham, J K; Carnevale, E M
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
Sousa, Ana Paula; Amaral, Alexandra; Baptista, Marta; Tavares, Renata; Caballero Campo, Pedro; Caballero Peregrín, Pedro; Freitas, Albertina; Paiva, Artur; Almeida-Santos, Teresa; Ramalho-Santos, João
Human sperm samples are very heterogeneous and include a low amount of truly functional gametes. Distinct strategies have been developed to characterize and isolate this specific subpopulation. In this study we have used fluorescence microscopy and fluorescence-activated cell sorting to determine if mitochondrial function, as assessed using mitochondrial-sensitive probes, could be employed as a criterion to obtain more functional sperm from a given ejaculate. We first determined that mitochondrial activity correlated with the quality of distinct human samples, from healthy donors to patients with decreased semen quality. Furthermore, using fluorescence-activated cell sorting to separate sperm with active and inactive mitochondria we found that this was also true within samples. Indeed, sperm with active mitochondria defined a more functional subpopulation, which contained more capacitated and acrosome intact cells, sperm with lower chromatin damage, and, crucially, sperm more able to decondense and participate in early development using both chemical induction and injection into mature bovine oocytes. Furthermore, cell sorting using mitochondrial activity produced a more functional sperm subpopulation than classic swim-up, both in terms of improvement in a variety of functional sperm parameters and in statistical significance. In conclusion, whatever the true biological role of sperm mitochondria in fertilization, mitochondrial activity is a clear hallmark of human sperm functionality. PMID:21448461
Binh, N T; Van Thuan, N; Miyake, M
The objective of this study was to clarify the effects of liquid preservation conditions on the ability of pig sperm to activate oocytes, form a male pronucleus, and initiate preimplantational development of embryos after intracytoplasmic sperm injection (ICSI). Porcine ejaculates were preserved at 4, 14, and 24 degrees C for up to 48h, and then damage to the plasma membrane, morphologic changes of the acrosome, and the amount of phospholipase Czeta (PLCzeta) in the sperm were assessed by SYBR-14/propidium iodide staining, fluorescein isothiocyanate-conjugated peanut agglutinin staining, indirect immunofluorescence, and Western blots, respectively. The proportion of sperm with a disintegrated plasma membrane or damaged acrosome increased in all samples as the duration of preservation increased, although the time courses of the increases varied among preservation temperatures. The immunolocalization and immunoreactivity of PLCzeta in the sperm showed its reduction concurrent with disintegration of the plasma membrane and acrosome. Rates of oocyte activation, male-pronuclear formation, and blastocyst formation after ICSI using sperm preserved for 18h at 24 degrees C (78%, 62%, and 35%, respectively) and for 48h at 14 degrees C (63%, 53%, and 28%, respectively) were significantly higher than those of any other sperm sample. We concluded that the damage to the plasma membrane and acrosome, and a sufficient amount of PLCzeta in the sperm head, enhanced successful oocyte activation, fertilization, and early development of the oocytes after ICSI. Moreover, we inferred that appropriate liquid preservation of sperm improved the efficiency of blastocyst production in vitro after ICSI in pigs.
Lee, Sang-Hee; Park, Choon-Keun
The objective of this study was to evaluate the effect of a magnetized extender on sperm membrane damage and development of oocytes in vitro fertilized with liquid storage boar semen. Before semen dilution, extender was flowed through a neodymium magnet (0, 2000, 4000 and 6000G) for 5min and collected semen was preserved for 168h at 18°C. In results, plasma membrane integrity with live sperm was significantly higher in semen treated with extenders magnetized at 4000G than sperm treated with extenders magnetized at 0G during semen preservation for 120-168h (p<0.05). In addition, acrosomal membrane damage was significantly lower in semen treated with extenders magnetized at 4000 and 6000G compared to 0 and 2000G during semen preservation for 168h (p<0.05). And mitochondrial membrane damage with all sperm was significantly lower in semen treated with extenders magnetized at 2000G than other groups during semen preservation for 168h. The ability of semen to achieve successful in vitro fertilization was also not significantly different among the groups during preservation. However, when the semen was preserved for 168h, the blastocyst formation rates were significantly higher at 6000G compared to 0 and 2000G (p<0.05). In conclusion, these results suggest that highly magnetized semen extender could protect the sperm membrane from damage, and improve the ability of rates of in vitro blastocyst development and magnetized semen diluter is beneficial for long liquid preservation of boar semen.
Knox, R V
One of the limits to practical use of frozen boar sperm involves the lowered fertility when used for artificial insemination. Years of studies have shown that 5-6 billion sperm (approximately 3 billion viable) used in single or multiple inseminations results in pregnancy rates most often between 60 and 70% and with litter sizes between nine and 10 pigs. Yet today, it is not uncommon for studies to report pregnancy rates from 70 to 85% and litter sizes with 11-12 pigs. While global statements about the incidence and reasons for higher fertility are not conclusive, incremental fertility improvements appear independently associated with use of a minimum number of viable sperm (1-2 billion), insemination timing that increases the probability that sperm will be present close to ovulation for groups of females, selection for boar sperm survival following cryopreservation, and modification of the freeze and thaw conditions using additives to protect sperm from oxidative damage. Studies show that techniques such as intrauterine and deep uterine insemination can provide an opportunity to reduce sperm numbers and that control of time of ovulation in groups of females can reduce the need for multiple inseminations and improve the chance for AI close to ovulation. However, optimal and consistent fertility with cryopreserved boar sperm may require a multifaceted approach that includes boar selection and screening, strategic use of additives during the freezing and thawing process, post-thaw evaluation of sperm and adjustments in sperm numbers for AI, assessment of female fertility and ovulation induction for single insemination. These sequenced procedures should be developed and incorporated into a quality control system for improved fertility when using minimal numbers of cryopreserved boar sperm.
Zheng, Ju-Fen; Chen, Xiao-Bao; Zhao, Lei-Wen; Gao, Min-Zhi; Peng, Jie; Qu, Xian-Qin; Shi, Hui-Juan; Jin, Xing-Liang
Azoospermia, cryptozoospermia and necrospermia can markedly decrease the ability of males to achieve pregnancy in fertile females. However, patients with these severe conditions still have the option to be treated by intracytoplasmic sperm injection (ICSI) to become biological fathers. This study analyzed the fertilization ability and the developmental viabilities of the derived embryos after ICSI treatment of the sperm from these patients compared with in vitro fertilization (IVF) treatment of the proven-fertile donor sperm on sibling oocytes as a control. On the day of oocyte retrieval, the number of sperm suitable for ICSI collected from two ejaculates or testicular sperm extraction was lower than the oocytes, and therefore, excess sibling oocytes were treated by IVF with donor sperm. From 72 couples (73 cycles), 1117 metaphase II oocytes were divided into 512 for ICSI and 605 for IVF. Compared with the control, husbands’ sperm produced a lower fertilization rate in nonobstructive azoospermia (65.4% vs 83.2%; P < 0.001), crytozoospermia (68.8% vs 75.5%; P < 0.05) and necrospermia (65.0% vs 85.2%; P < 0.05). The zygotes derived in nonobstructive azoospermia had a lower cleavage rate (96.4% vs 99.4%; P < 0.05), but the rate of resultant good-quality embryos was not different. Analysis of the rates of cleaved and good-quality embryos in crytozoospermia and necrospermia did not exhibit a significant difference from the control. In conclusion, although the sperm from severe male infertility reduced the fertilization ability, the derived embryos had potential developmental viabilities that might be predictive for the expected clinical outcomes. PMID:25652630
Zheng, Ju-Fen; Chen, Xiao-Bao; Zhao, Lei-Wen; Gao, Min-Zhi; Peng, Jie; Qu, Xian-Qin; Shi, Hui-Juan; Jin, Xing-Liang
Azoospermia, cryptozoospermia and necrospermia can markedly decrease the ability of males to achieve pregnancy in fertile females. However, patients with these severe conditions still have the option to be treated by intracytoplasmic sperm injection (ICSI) to become biological fathers. This study analyzed the fertilization ability and the developmental viabilities of the derived embryos after ICSI treatment of the sperm from these patients compared with in vitro fertilization (IVF) treatment of the proven-fertile donor sperm on sibling oocytes as a control. On the day of oocyte retrieval, the number of sperm suitable for ICSI collected from two ejaculates or testicular sperm extraction was lower than the oocytes, and therefore, excess sibling oocytes were treated by IVF with donor sperm. From 72 couples (73 cycles), 1117 metaphase II oocytes were divided into 512 for ICSI and 605 for IVF. Compared with the control, husbands' sperm produced a lower fertilization rate in nonobstructive azoospermia (65.4% vs 83.2%; P< 0.001), crytozoospermia (68.8% vs 75.5%; P< 0.05) and necrospermia (65.0% vs 85.2%; P< 0.05). The zygotes derived in nonobstructive azoospermia had a lower cleavage rate (96.4% vs 99.4%; P< 0.05), but the rate of resultant good-quality embryos was not different. Analysis of the rates of cleaved and good-quality embryos in crytozoospermia and necrospermia did not exhibit a significant difference from the control. In conclusion, although the sperm from severe male infertility reduced the fertilization ability, the derived embryos had potential developmental viabilities that might be predictive for the expected clinical outcomes.
Herrero, María Belén; Mandal, Arabinda; Digilio, Laura C; Coonrod, Scott A; Maier, Bernhard; Herr, John C
This study demonstrates the retention of mouse sperm lysozyme-like protein (mSLLP1) in the equatorial segment of spermatozoa following the acrosome reaction and a role for mSLLP1 in sperm-egg binding and fertilization. Treatment of cumulus intact oocytes with either recmSLLP1 or its antiserum resulted in a significant (P < or = 0.05) inhibition of fertilization. Co-incubation of zona-free mouse oocytes with capacitated mouse spermatozoa in the presence of varying concentrations of anti-recmSLLP1 serum or recmSLLP1 also inhibited sperm-oolemma binding. A complete inhibition of binding and fusion of spermatozoa to the oocyte occurred at 12.5 muM concentration of recmSLLP1, while conventional chicken and human lysozymes did not block sperm-egg binding. mSLLP1 showed receptor sites in the perivitelline space as well as on the microvillar region of the egg plasma membrane. The retention of mSLLP1 in the equatorial segment of acrosome-reacted sperm, the inhibitory effects of both recmSLLP1 and antibodies to SLLP1 on in vitro fertilization with both cumulus intact and zona-free eggs, and the definition of complementary SLLP1-binding sites on the egg plasma membrane together support the hypothesis that a c lysozyme-like protein is involved in the binding of spermatozoa to the egg plasma membrane during fertilization.
Semen quality in poultry can be characterized by different phenotypic traits including volume, concentration, mobility, viability, and sperm morphology. To date, sperm mobility phenotype has been shown to be the most reliable indicator of male fertilizing potential under artificial insemination (AI...
Frozen-thawed boar sperm is seldom used for artificial insemination (AI) because fertility is lower than fresh or cooled semen. Despite the many advantages of AI including reduced pathogen exposure and ease of semen transport, cryo-induced damage to sperm usually results in decreased litter sizes a...
We previously established that the levels sperm membrane protein SP22 are highly correlated with the fertility of sperm from the cauda epididymidis of rats exposed to both epididymal and testicular toxicants, and that a testis-specific SP22 transcript is expressed in post-meiotic...
Soler, Laura; Labas, Valérie; Thélie, Aurore; Grasseau, Isabelle; Teixeira-Gomes, Ana-Paula; Blesbois, Elisabeth
Currently, evaluation of sperm quality is primarily based on in vitro measures of sperm function such as motility, viability and/or acrosome reaction. However, results are often poorly correlated with fertility, and alternative diagnostic tools are therefore needed both in veterinary and human medicine. In a recent pilot study, we demonstrated that MS profiles from intact chicken sperm using MALDI-TOF profiles could detect significant differences between fertile/subfertile spermatozoa showing that such profiles could be useful for in vitro male fertility testing. In the present study, we performed larger standardized experimental procedures designed for the development of fertility- predictive mathematical models based on sperm cell MALDI-TOF MS profiles acquired through a fast, automated method. This intact cell MALDI-TOF MS-based method showed high diagnostic accuracy in identifying fertile/subfertile males in a large male population of known fertility from two distinct genetic lineages (meat and egg laying lines). We additionally identified 40% of the m/z peaks observed in sperm MS profiles through a top-down high-resolution protein identification analysis. This revealed that the MALDI-TOF MS spectra obtained from intact sperm cells contained a large proportion of protein degradation products, many implicated in important functional pathways in sperm such as energy metabolism, structure and movement. Proteins identified by our predictive model included diverse and important functional classes providing new insights into sperm function as it relates to fertility differences in this experimental system. Thus, in addition to the chicken model system developed here, with the use of appropriate models these methods should effectively translate to other animal taxa where similar tests for fertility are warranted.
KOMORI, S; KAMEDA, K; SAKATA, K; HASEGAWA, A; TOJI, H; TSUJI, Y; SHIBAHARA, H; KOYAMA, K; ISOJIMA, S
A mouse hybridoma (1G12) producing sperm-immobilizing MoAb to human sperm was established and characterized in order to study the antigens relevant to sperm immobilization by antibodies. MoAb 1G12 had strong sperm-immobilizing and agglutinating activities and also showed a fertilization-blocking activity on in vitro fertilization tests. The antibody absorption experiments showed that MoAb 1G12 reacted not only to ejaculated sperm but also human seminal plasma, suggesting that the corresponding antigen might be a sperm coating antigen. The MoAb also reacted with peripheral blood lymphocytes. In histochemical studies, the epithelia of corpus epididymis were most strongly stained. Ejaculated sperm were stained with a granular pattern for their entire surface by immunofluorescence. MoAb 1G12 recognized polymorphic glycoproteins of 15–25 kD in the ejaculated sperm extract in Western blot analysis. After deglycosilation of the sperm extract, only a single staining band of under 15 kD was detected by MoAb 1G12. This suggests that the antigen epitope recognized by MoAb 1G12 might be a peptide of the core portion of the glycoprotein. MoAb 1G12 might be a useful tool for studying the mechanism of egg–sperm interaction, and also be applied to identifying the corresponding antigen by using gene technology. PMID:9328135
Finkelstein, Maya; Etkovitz, Nir; Breitbart, Haim
To acquire fertilization competence, spermatozoa should undergo several biochemical changes in the female reproductive tract, known as capacitation. The capacitated spermatozoon can interact with the egg zona pellucida resulting in the occurrence of the acrosome reaction, a process that allowed its penetration into the egg and fertilization. Sperm capacitation requires actin polymerization, whereas F-actin must disperse prior to the acrosome reaction. Here, we suggest that the actin-severing protein, gelsolin, is inactive during capacitation and is activated prior to the acrosome reaction. The release of bound gelsolin from phosphatidylinositol 4,5-bisphosphate (PIP2) by PBP10, a peptide containing the PIP2-binding domain of gelsolin, or by activation of phospholipase C, which hydrolyzes PIP2, caused rapid Ca2+-dependent F-actin depolymerization as well as enhanced acrosome reaction. Using immunoprecipitation assays, we showed that the tyrosine kinase SRC and gelsolin coimmunoprecipitate, and activating SRC by adding 8-bromo-cAMP (8-Br-cAMP) enhanced the amount of gelsolin in this precipitate. Moreover, 8-Br-cAMP enhanced tyrosine phosphorylation of gelsolin and its binding to PIP2(4,5), both of which inactivated gelsolin, allowing actin polymerization during capacitation. This actin polymerization was blocked by inhibiting the Src family kinases, suggesting that gelsolin is activated under these conditions. These results are further supported by our finding that PBP10 was unable to cause complete F-actin breakdown in the presence of 8-Br-cAMP or vanadate. In conclusion, inactivation of gelsolin during capacitation occurs by its binding to PIP2 and tyrosine phosphorylation by SRC. The release of gelsolin from PIP2 together with its dephosphorylation enables gelsolin activation, resulting in the acrosome reaction. PMID:20937821
López-Saucedo, J; Santiago-Moreno, J; Fierro, R; Izquierdo, D; Coloma, M A; Catalá, M G; Jiménez, I; Paramio, M T
In vitro fertilization (IVF) can be used to assess the fertilization capacity of sperm. Heterologous IVF may be useful when assessing that of wild animals as it is often difficult to obtain adequate numbers of naturally corresponding oocytes. The aim of the present study was to assess the fertilization capacity of frozen-thawed ibex epididymal spermatozoa via heterologous IVF involving the oocytes of prepubertal domestic goats. The effect on fertilization and embryo development of adding oestrous sheep serum (ESS) to the fertilization medium was also examined. Cumulus-oocyte complexes (COCs) were matured in TCM-199 for 24-27 h at 38.5°C in a 5% CO2 in air atmosphere. Frozen-thawed epididymal spermatozoa were selected by density gradient centrifugation. After maturation, the oocytes were co-incubated with spermatozoa in synthetic oviductal fluid (SOF) with different concentrations of ESS: SOF-C (0%), SOF-2 (2%) and SOF-20 (20%). At 17 h post-insemination (hpi), zygotes with one female and one male pronucleus (2PN) were categorised as normal; zygotes with 3PN were recorded as polyspermic, and oocytes with 1PN as asynchronous. Cleavage and blastocyst development were assessed at 48 and 168 hpi respectively. The percentage of zygotes with 2PN was higher in the SOF-2 than in the SOF-20 treatment group (27.7% versus 2.9% P < 0.05). The percentage of blastocysts formed with the SOF-C, SOF-2 and SOF-20 treatments were 1.1%, 7.5% and 0% respectively. These results show that the presence of 2% ESS achieves better results than the use of no serum or the standard 20% concentration. Heterologous IVF may be an effective method for predicting the fertilization capacity of ibex spermatozoa, and therefore perhaps that of other wild mountain ungulates.
Medina-Sánchez, Mariana; Schwarz, Lukas; Meyer, Anne K; Hebenstreit, Franziska; Schmidt, Oliver G
We present artificially motorized sperm cells-a novel type of hybrid micromotor, where customized microhelices serve as motors for transporting sperm cells with motion deficiencies to help them carry out their natural function. Our results indicate that metal-coated polymer microhelices are suitable for this task due to potent, controllable, and nonharmful 3D motion behavior. We manage to capture, transport, and release single immotile live sperm cells in fluidic channels that allow mimicking physiological conditions. Important steps toward fertilization are addressed by employing proper means of sperm selection and oocyte culturing. Despite the fact that there still remain some challenges on the way to achieve successful fertilization with artificially motorized sperms, we believe that the potential of this novel approach toward assisted reproduction can be already put into perspective with the present work.
Duan, Qiaohong; Kita, Daniel; Johnson, Eric A.; Aggarwal, Mini; Gates, Laura; Wu, Hen-Ming; Cheung, Alice Y.
In flowering plants, sperm are transported inside pollen tubes to the female gametophyte for fertilization. The female gametophyte induces rupture of the penetrating pollen tube, resulting in sperm release and rendering them available for fertilization. Here we utilize the Arabidopsis FERONIA (FER) receptor kinase mutants, whose female gametophytes fail to induce pollen tube rupture, to decipher the molecular mechanism of this critical male-female interactive step. We show that FER controls the production of high levels of reactive oxygen species at the entrance to the female gametophyte to induce pollen tube rupture and sperm release. Pollen tube growth assays in vitro and in the pistil demonstrate that hydroxyl free radicals are likely the most reactive oxygen molecules, and they induce pollen tube rupture in a Ca2+-dependent process involving Ca2+ channel activation. Our results provide evidence for a RHO GTPase-based signalling mechanism to mediate sperm release for fertilization in plants.
Niu, Yuyu; Greube, Alexa; Ji, Weizhi; Jewgenow, Katarina
The present study aimed to establish a sensitive in vitro assay to assess the binding capacity of cat spermatozoa. Cat oocytes and epididymal sperm cells were isolated from gonads and cultured for in vitro fertilization. Before fertilization, the sperm cells were incubated either in 10 microM green dye Fluo-3-AM or 10 microM orange dye CellTracker Orange CMTMR (Molecular Probes), respectively. After removing the dyes by washing, sperm cells stained with each dye were added to medium drops containing oocytes in various proportions and cultured for 16 h at 37 degrees C, 5% CO(2). The oocytes were examined using fluorescence microscopy. Sperm bound to oocytes, and stained with different colors, were counted. When fresh epididymal sperm were mixed in at a specific proportion, the number of sperm bound to the zona pellucida (ZP) of oocytes reflected the proportion of differently colored sperm in the medium. This indicated that neither dye influenced the binding capacity of cat sperm. Mixing fresh and cryopreserved sperm, however, resulted in a higher number of fresh sperm bound to the oocyte surface in comparison to frozen-thawed sperm. Also, the pre-incubation of cat sperm cells with ZP derived peptide reduced the sperm binding capacity by 40%. In conclusion, the presented sperm competition assay allows assessment of fertilizing capacity of cat spermatozoa in vitro when a mixture of two different populations is used. The applied supravital fluorescence dyes do not affect motility and binding capacity of sperm cells and were clearly distinguishable under fluorescence microscopy. We demonstrate that the assay can be used to study the impact of sperm treatment, such as cryopreservation or pre-incubation in bioactive peptides, on fertilizing capacity.
Ozkosem, Burak; Feinstein, Sheldon I.; Fisher, Aron B.; O’Flaherty, Cristian
Due to socioeconomic factors, more couples are choosing to delay conception than ever. Increasing average maternal and paternal age in developed countries over the past 40 years has raised the question of how aging affects reproductive success of males and females. Since oxidative stress in the male reproductive tract increases with age, we investigated the impact of advanced paternal age on the integrity of sperm nucleus and reproductive success of males by using a Prdx6−/− mouse model. We compared sperm motility, cytoplasmic droplet retention sperm chromatin quality and reproductive outcomes of young (2-month-old), adult (8-month-old), and old (20-month-old) Prdx6−/− males with their age-matched wild type (WT) controls. Absence of PRDX6 caused age-dependent impairment of sperm motility and sperm maturation and increased sperm DNA fragmentation and oxidation as well as decreased sperm DNA compaction and protamination. Litter size, total number of litters and total number of pups per male were significantly lower in Prdx6−/− males compared to WT controls. These abnormal reproductive outcomes were severely affected by age in Prdx6−/− males. In conclusion, the advanced paternal age affects sperm chromatin integrity and fertility more severely in the absence of PRDX6, suggesting a protective role of PRDX6 in age-associated decline in the sperm quality and fertility in mice. PMID:25796034
Dorado, J; Acha, D; Ortiz, I; Gálvez, M J; Carrasco, J J; Díaz, B; Gómez-Arrones, V; Calero-Carretero, R; Hidalgo, M
Sperm quality has an important role in determining fertility. The aims of this study were to compare the conventional sperm parameters, plus the characteristics of the motility patterns of the different sperm subpopulations, of donkey donors with different fertility level, and to determine their relationships to fertility. Thirty ejaculates from 6 Andalusian donkeys were assessed for gel-free volume, pH, sperm concentration, motility and morphology. The fertility of donkeys was classified on the basis of pregnancy rates per cycle, where donkeys with a per cycle pregnancy rate ≥60% were considered to be "fertile" (n=3) and those with a per cycle pregnancy rate <40% were categorized to be "sub-fertile" (n=3). Significant differences (P<0.001) between the "fertile" and the "sub-fertile" group were found for total and progressive motility, and for straight line velocity. Sperm variables associated (P<0.05) with an increase in percent pregnant per cycle included total motility (r=0.37), progressive motility (r=0.53), curvilinear velocity (r=0.44), straightness (r=0.39), beat cross frequency (r=0.44), and gel-free volume (r=0.53). Four sperm subpopulations (sP) were identified in fresh semen: sP1 (slow and non-progressive spermatozoa, 20%), sP2 (moderately slow but progressive spermatozoa, 71.2%), sP3 (highly active but non-progressive spermatozoa, 2.9%), and sP4 (highly active and progressive spermatozoa, 5.9%). The lowest percentage (3.1%; P<0.001) of sP4 spermatozoa was observed in the "sub-fertile" group. Three of the sperm subpopulations were related (P<0.05) to fertility (sP2, r=0.54; sP3, r=0.45; sP4, r=0.56). In conclusion, we were able to relate the fertility of donkeys with in vitro measures of sperm motility using computer-assisted sperm analysis techniques.
Song, Won-Hee; Yi, Young-Joo; Sutovsky, Miriam; Meyers, Stuart; Sutovsky, Peter
Maternal inheritance of mitochondria and mtDNA is a universal principle in human and animal development, guided by selective ubiquitin-dependent degradation of the sperm-borne mitochondria after fertilization. However, it is not clear how the 26S proteasome, the ubiquitin-dependent protease that is only capable of degrading one protein molecule at a time, can dispose of a whole sperm mitochondrial sheath. We hypothesized that the canonical ubiquitin-like autophagy receptors [sequestosome 1 (SQSTM1), microtubule-associated protein 1 light chain 3 (LC3), gamma-aminobutyric acid receptor-associated protein (GABARAP)] and the nontraditional mitophagy pathways involving ubiquitin-proteasome system and the ubiquitin-binding protein dislocase, valosin-containing protein (VCP), may act in concert during mammalian sperm mitophagy. We found that the SQSTM1, but not GABARAP or LC3, associated with sperm mitochondria after fertilization in pig and rhesus monkey zygotes. Three sperm mitochondrial proteins copurified with the recombinant, ubiquitin-associated domain of SQSTM1. The accumulation of GABARAP-containing protein aggregates was observed in the vicinity of sperm mitochondrial sheaths in the zygotes and increased in the embryos treated with proteasomal inhibitor MG132, in which intact sperm mitochondrial sheaths were observed. Pharmacological inhibition of VCP significantly delayed the process of sperm mitophagy and completely prevented it when combined with microinjection of autophagy-targeting antibodies specific to SQSTM1 and/or GABARAP. Sperm mitophagy in higher mammals thus relies on a combined action of SQSTM1-dependent autophagy and VCP-mediated dislocation and presentation of ubiquitinated sperm mitochondrial proteins to the 26S proteasome, explaining how the whole sperm mitochondria are degraded inside the fertilized mammalian oocytes by a protein recycling system involved in degradation of single protein molecules. PMID:27551072
Dogan, Sule; Vargovic, Peter; Oliveira, Rodrigo; Belser, Lauren E; Kaya, Abdullah; Moura, Arlindo; Sutovsky, Peter; Parrish, John; Topper, Einko; Memili, Erdoğan
During fertilization, spermatozoa make essential contributions to embryo development by providing oocyte activating factors, centrosomal components, and paternal chromosomes. Protamines are essential for proper packaging of sperm DNA; however, in contrast to the studies of oocyte-related female infertility, the influence of sperm chromatin structure on male infertility has not been evaluated extensively. The objective of this study was to determine the sperm chromatin content of bull spermatozoa by evaluating DNA fragmentation, chromatin maturity/protamination, PRM1 protein status, and nuclear shape in spermatozoa from bulls with different fertility. Relationships between protamine 1 (PRM1) and the chromatin integrity were ascertained in spermatozoa from Holstein bulls with varied (high vs. low) but acceptable fertility. Sperm DNA fragmentation and chromatin maturity (protamination) were tested using Halomax assay and toluidine blue staining, respectively. The PRM1 content was assayed using Western blotting and in-gel densitometry, flow cytometry, and immunocytochemistry. Fragmentation of DNA was increased and chromatin maturity significantly reduced in spermatozoa from low-fertility bulls compared to those from high-fertility bulls. Field fertility scores of the bulls were negatively correlated with the percentage of spermatozoa displaying reduced protamination and fragmented DNA using toluidine blue and Halomax, respectively. Bull fertility was also positively correlated with PRM1 content by Western blotting and flow cytometry. However, detection of PRM1 content by Western blotting alone was not predictive of bull fertility. In immunocytochemistry, abnormal spermatozoa showed either a lack of PRM1 or scattered localization in the apical/acrosomal region of the nuclei. The nuclear shape was distorted in spermatozoa from low-fertility bulls. In conclusion, we showed that inadequate amount and localization of PRM1 were associated with defects in sperm chromatin
Cryopreserved semen is seldom used for commercial porcine artificial insemination (AI) despite many advantages that cryopreservation provides. Compared to fresh semen, the fertility of frozen-thawed boar sperm is more variable but usually less. Predicting the fertility of individual ejaculates for s...
Hamoutene, Dounia; Samuelson, S; Lush, L; Burt, K; Drover, D; King, T; Lee, K
The in vitro effect of produced water released by oil and gas platforms was assessed by exposing cod sperm cells to realistic concentrations of this mixture (100, 200, 500 ppm). We investigated produced water impact on enzymes of the aerobic (citrate synthase) and glycolytic metabolism (lactate dehydrogenase), lipid catabolism (lipase), as well as an anti-oxidant enzyme (catalase). Fertilization rates, viability, respiration, ATP, and total motility duration were also evaluated. To explore correlations between these parameters, we have also tested the effect of conserving sperm for 24 h at 4 degrees C. After conservation, fertilization success was decreased but other parameters were not affected. Produced water did not result in a significant change in fertilization; a significant increase in sperm protein amounts and citrate synthase activity can be observed. No correlations are found between parameters showing that sperm viability and unchanged energy levels do not translate into equivalent fertilization capacity. To conclude, exposure of sperm to produced water resulted only in subtle effects on cells. These findings bring information on the effect of produced water on sperm itself rather than on spermatogenesis or testis development of an exposed fish.
Garoussi, M Talebkhan; Mehrzad, J
Bovine viral diarrhoea virus (BVDV), a member of the Pestivirus genus, is one of the most important pathogens of dairy cattle; it can cause several clinical syndromes, ranging from subclinical to severe disease. The objectives of the current studies were to assess the effects of two biotypes of BVDV on sperm attachment to the zona pellucida (ZP) of oocytes and on fertilization rate in bovine in vitro fertilization (IVF). In two experiments, sperm at two concentrations (10⁵ and 10⁶/mL) and oocytes were incubated with 10⁶ TCID₅₀/mL cythopatic (CP) or noncythopatic (NCP) BVDV. In the first experiment, with the lower sperm concentration (10⁵/mL), male and female gametes were infected with CP or NCP BVDV, whereas in the second experiment, the sperm concentration was 10⁶/mL, and sperm and oocytes were also infected with CP or NCP BVDV. The number of sperm attached to the ZP and the fertilization rate were evaluated with fluorescence microscopy on the ZP of fertile and infertile oocytes. In the first experiment, compared to the control group (n = 97), oocytes infected with CP BVDV and incubated at the lower (10⁵/mL) sperm concentration positively affected sperm attachment (n = 123) to the ZP of fertile oocytes (P < 0.05). In comparison with the control group (n = 115), sperm infected with CP BVDV negatively affected sperm binding (n = 93) to the ZP of infertile oocytes (P < 0.05). In the second experiment (10⁶ sperm/mL), for both fertile and infertile oocyte groups, sperm attachment in the control group was very high and deemed uncountable. However, in treated groups, the number of sperm attached to the ZP was countable. Only sperm infected with CP BVDV negatively affected sperm binding capacity (n = 81) to the ZP of fertile oocytes (P < 0.05). Although CP and NCP BVDV significantly reduced the fertilization rate of oocytes incubated with a higher sperm concentration, with the lower sperm concentration, only NCP BVDV significantly diminished
Arroteia, Kélen Fabíola; Barbieri, Mainara Ferreira; Souza, Gustavo Henrique Martins Ferreira; Tanaka, Hiromitsu; Eberlin, Marcos Nogueira; Hyslop, Stephen; Alvares, Lúcia Elvira; Pereira, Luís Antonio Violin Dias
The epididymis has an important role in the maturation of sperm for fertilization, but little is known about the epididymal molecules involved in sperm modifications during this process. We have previously described the expression pattern for an antigen in epididymal epithelial cells that reacts with the monoclonal antibody (mAb) TRA 54. Immunohistochemical and immunoblotting analyses suggest that the epitope of the epididymal antigen probably involves a sugar moiety that is released into the epididymal lumen in an androgen-dependent manner and subsequently binds to luminal sperm. Using column chromatography, SDS-PAGE with in situ digestion and mass spectrometry, we have identified the protein recognized by mAb TRA 54 in mouse epididymal epithelial cells. The ∼65 kDa protein is part of a high molecular mass complex (∼260 kDa) that is also present in the sperm acrosomal vesicle and is completely released after the acrosomal reaction. The amino acid sequence of the protein corresponded to that of albumin. Immunoprecipitates with anti-albumin antibody contained the antigen recognized by mAb TRA 54, indicating that the epididymal molecule recognized by mAb TRA 54 is albumin. RT-PCR detected albumin mRNA in the epididymis and fertilization assays in vitro showed that the glycoprotein complex containing albumin was involved in the ability of sperm to recognize and penetrate the egg zona pellucida. Together, these results indicate that epididymal-derived albumin participates in the formation of a high molecular mass glycoprotein complex that has an important role in egg fertilization.
Daigneault, Bradford W; McNamara, Kelli A; Purdy, Phillip H; Krisher, Rebecca L; Knox, Robert V; Miller, David J
Cryopreserved semen allows the use of single ejaculates for repeated analyses, potentially improving IVF consistency by eliminating interejaculate variability observed with fresh semen. However, the freezing and thawing processes result in compromised sperm function and IVF success. Semen samples are often screened for motility before use for IVF. Samples that are below a designated motility threshold may be discarded. Our objectives were to determine if post-thaw sperm motility, other traits that may be indicative of sperm function, or a novel assay of oviduct binding were related to IVF success. Semen from 16 boars was cooled to 15 °C for overnight shipment before cryopreservation. Semen was thawed and motility was recorded microscopically and confirmed using computer-automated sperm assessment. Each sample was tested by IVF in two to three independent replicates. Regression and correlation analyses were employed to determine the interrelationships between sperm traits and the relationships between post-thaw motility, sperm-oviduct binding and IVF outcomes. Among the sperm traits examined, sperm acrosome integrity was negatively correlated with post-thaw motility (r(2) = 0.64) but not with IVF results. The number of sperm bound to oviduct aggregates was correlated with IVF polyspermy rates (r(2) = 0.62, P < 0.05) but less with overall IVF rates (r(2) = 0.31, P > 0.10). There was some relationship of post-thaw motility with IVF monospermic fertilization (P = 0.06, r(2) = 0.08) but not to other IVF outcomes. Our results indicate that post-thaw motility of frozen-thawed boar sperm is strongly related to acrosome integrity but has limited use for predicting IVF success. The number of sperm bound to oviduct cells was related to IVF polyspermy rates and may be more indicative of in vitro sperm function than traditional sperm motility and acrosome status evaluation.
Colagar, Abasalt Hosseinzadeh; Marzony, Eisa Tahmasbpour; Chaichi, Mohammad Javad
Zinc has antioxidative properties and plays an important role in scavenging reactive oxygen species. We hypothesized that in the absence of Zn, the possibility of increased oxidative damage exists that would contribute to poor sperm quality. Therefore, measurement of seminal Zn in the seminal plasma of males with a history of subfertility or idiopathic infertility is necessary and can be helpful in fertility assessment. The primary objective of the present study was to assess the relationship between Zn levels in seminal plasma with sperm quality in fertile and infertile men. Semen samples were provided by fertile (smoker [n = 17], nonsmoker [n = 19]) and infertile men (smoker [n = 15], nonsmoker [n = 21]). After semen analysis, concentrations of Zn, Mg, Ca, Na, and K in the seminal plasma of all groups were determined by atomic absorption spectroscopy. Element concentrations in seminal plasma of all groups were in the order Na > K > Ca > Zn > Mg. Fertile subjects, smoker or not, demonstrated significantly higher seminal Zn levels than any infertile group (P < .001). A trend was observed for a lower Zn levels in seminal plasma of smokers compared with nonsmokers. Seminal Zn in fertile and infertile (smokers or nonsmokers) males correlated significantly with sperm count (P < .01) and normal morphology of sperm (P < .001). There was a significantly positive correlation between seminal Zn with Ca (P < .01) and K (P < .01) levels in all specimens. In conclusion, poor Zn nutrition may be an important risk factor for low quality of sperm and idiopathic male infertility.
Gómez Montoto, Laura; Magaña, Concepción; Tourmente, Maximiliano; Martín-Coello, Juan; Crespo, Cristina; Luque-Larena, Juan José
Sperm competition favors increases in relative testes mass and production efficiency, and changes in sperm phenotype that result in faster swimming speeds. However, little is known about its effects on traits that contribute to determine the quality of a whole ejaculate (i.e., proportion of motile, viable, morphologically normal and acrosome intact sperm) and that are key determinants of fertilization success. Two competing hypotheses lead to alternative predictions: (a) sperm quantity and quality traits co-evolve under sperm competition because they play complementary roles in determining ejaculate's competitive ability, or (b) energetic constraints force trade-offs between traits depending on their relevance in providing a competitive advantage. We examined relationships between sperm competition levels, sperm quantity, and traits that determine ejaculate quality, in a comparative study of 18 rodent species using phylogenetically controlled analyses. Total sperm numbers were positively correlated to proportions of normal sperm, acrosome integrity and motile sperm; the latter three were also significantly related among themselves, suggesting no trade-offs between traits. In addition, testes mass corrected for body mass (i.e., relative testes mass), showed a strong association with sperm numbers, and positive significant associations with all sperm traits that determine ejaculate quality with the exception of live sperm. An “overall sperm quality” parameter obtained by principal component analysis (which explained 85% of the variance) was more strongly associated with relative testes mass than any individual quality trait. Overall sperm quality was as strongly associated with relative testes mass as sperm numbers. Thus, sperm quality traits improve under sperm competition in an integrated manner suggesting that a combination of all traits is what makes ejaculates more competitive. In evolutionary terms this implies that a complex network of genetic and
Dibromoacetic acid (DBA) and bromochloroacetic acid (BCA) are prevalent disinfection by-products of drinking water that produce defects in spermatogenesis and fertility in adult rats. Previously we demonstrated that BCA compromises the fertility of cauda epididymal rat sperm an...
Horvath, A.; Wayman, W.R.; Dean, J.C.; Urbanyi, B.; Tiersch, T.R.; Mims, S.D.; Johnson, D.; Jenkins, J.A.
Populations of sturgeon across the globe are threatened due to unregulated harvest and habitat loss, and the status varies among species across North America. Ready access to viable and functional sperm would contribute to recovery programmes for these species. In this study, we examined the motility, viability (cell membrane integrity) of cryopreserved sperm from three North American acipenseriform species and fertilizing capacity. Milt samples were collected from captive shortnose sturgeon (Acipenser brevirostrum), wild paddlefish (Polyodon spathula) and pallid sturgeon (Scaphirhynchus albus) and cryopreserved using combinations of Modified Tsvetkova's (MT) extender, Original Tsvetkova's extender, and modified Hanks' balanced salt solution, along with the cryoprotectants methanol (MeOH) or dimethyl sulfoxide (DMSO). A dual-staining technique using the fluorescent stains SYBR-14 and propidium iodide was employed with flow cytometry to determine the percentages of spermatozoa that were viable by virtue of having intact membranes. The percentage of viable spermatozoa ranged from 5% to 12% in shortnose sturgeon, 30-59% in paddlefish, and 44-58% in pallid sturgeon. In the first experiment with shortnose sturgeon sperm, methanol allowed for higher values for dependent variables than did DMSO, and sperm viability generally correlated with post-thaw motility. However, fertilization rate, neurulation, or hatching rates were independent from these factors. In the second experiment with shortnose sturgeon, 5% MeOH combined with MT yielded higher values for all parameters tested than the other combinations: viability was correlated with motility, fertilization rate, and hatching rate. Overall, viability and post-thaw motility was not affected by the use of hyperosmotic extenders (OT) or cryoprotectants (DMSO), but their use decreased fertilization percentages. For paddlefish sperm (experiment 3), MT combined with 10% MeOH was clearly a good choice for cryopreservation
The sperm acrosome reaction is a Ca(2+)-dependent secretory event required for fertilization. Adhesion to the egg's zona pellucida promotes Ca2+ influx through voltage-sensitive channels, thereby initiating secretion. We used potentiometric fluorescent probes to determine the role of sperm membrane potential in regulating Ca2+ entry. ZP3, the glycoprotein agonist of the zona pellucida, depolarizes sperm membranes by activating a pertussis toxin-insensitive mechanism with the characteristics of a poorly selective cation channel. ZP3 also activates a pertussis toxin-sensitive pathway that produces a transient rise in internal pH. The concerted effects of depolarization and alkalinization open voltage-sensitive Ca2+ channels. These observations suggest that mammalian sperm utilize membrane potential-dependent signal transduction mechanisms and that a depolarization pathway is an upstream transducing element coupling adhesion to secretion during fertilization. PMID:8707844
Li, Le-Jun; Zhang, Feng-Bin; Liu, Shu-Yuan; Tian, Yong-Hong; Le, Fang; Wang, Li-Ya; Lou, Hang-Ying; Xu, Xiang-Rong; Huang, He-Feng; Jin, Fan
In conventional in vitro fertilization (IVF), complete failure of fertilization occurs in 5% to 15% of treatments. Although the causes may be unclear, sperm defects appear to be the major contributor. However, a convincing test is not yet available that can predict the risk of fertilization failure. In this study, we found that germinal angiotensin-converting enzyme (gACE) (also called testicular ACE) was undetectable in sperm from patients who had total fertilization failure (TFF) and lower fertilization rates (LFRs) by IVF based on Western blot and indirect immunofluorescence analyses. Additionally, almost all of the patients without gACE on sperm (23 of 25) manifested a TT genotype of the rs4316 single-nucleotide polymorphism of ACE. Overall, our results indicate that the absence of gACE expression is responsible for TFF and LFRs by IVF. The rs4316 polymorphism of ACE might be associated with infertility in those patients. We conclude that sperm lacking gACE may be recognized before commencing IVF and that the patients may be directed instead to consider intracytoplasmic sperm injection.
Aydin, Halil; Sultana, Azmiri; Li, Sheng; Thavalingam, Annoj; Lee, Jeffrey E
Fertilization is an essential biological process in sexual reproduction and comprises a series of molecular interactions between the sperm and egg. The fusion of the haploid spermatozoon and oocyte is the culminating event in mammalian fertilization, enabling the creation of a new, genetically distinct diploid organism. The merger of two gametes is achieved through a two-step mechanism in which the sperm protein IZUMO1 on the equatorial segment of the acrosome-reacted sperm recognizes its receptor, JUNO, on the egg surface. This recognition is followed by the fusion of the two plasma membranes. IZUMO1 and JUNO proteins are indispensable for fertilization, as constitutive knockdown of either protein results in mice that are healthy but infertile. Despite their central importance in reproductive medicine, the molecular architectures of these proteins and the details of their functional roles in fertilization are not known. Here we present the crystal structures of human IZUMO1 and JUNO in unbound and bound conformations. The human IZUMO1 structure exhibits a distinct boomerang shape and provides structural insights into the IZUMO family of proteins. Human IZUMO1 forms a high-affinity complex with JUNO and undergoes a major conformational change within its N-terminal domain upon binding to the egg-surface receptor. Our results provide insights into the molecular basis of sperm-egg recognition, cross-species fertilization, and the barrier to polyspermy, thereby promising benefits for the rational development of non-hormonal contraceptives and fertility treatments for humans and other mammals.
Pathak, Piyush; Chandrashekar, Aravind; Hakky, Tariq S; Pastuszak, Alexander W
Varicocele is the most common surgically treatable cause of male infertility, and often results in alterations in semen parameters, sperm DNA damage, and changes to the seminal milieu. Varicocele repair can result in improvement in these parameters in the majority of men with clinical varicocele; data supporting repair in men with subclinical varicocele are less definitive. In couples seeking fertility using assisted reproductive technologies (ARTs), varicocele repair may offer improvement in semen parameters and sperm health that can increase the likelihood of successful fertilization using techniques such as in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI), or may decrease the level of ART needed to achieve successful pregnancy. Male infertility is an indicator of general male health, and evaluation of the infertile male with an eye toward future health can facilitate optimal screening and treatment of these men. Furthermore, varicocele may represent a progressive lesion, offering an argument for its repair, although this is currently unclear. PMID:27030086
Sato, Takahiro; Ban, Yoshiki; Uchida, Miki; Gondo, Eri; Yamamoto, Masakatsu; Sekiguchi, Yoshiko; Sakaue, Akiko; Kemi, Masayuki; Nakatsuka, Toshio
Previous studies revealed that atropine reduced male fertility in rats without any effects on mating performance, sperm production and motility, and testicular morphology. The present study was conducted to investigate whether the impairment of male fertility induced by atropine was related to the inhibition of sperm and semen transports from the vas deferens and seminal vesicle to the urethra during the process of emission. Male rats were treated with atropine at 125 mg/kg/day for 10-17 days prior to mating with untreated females. After confirmation of mating, male rats were euthanized and sperm number in the vas deferens and weights of the seminal vesicle and copulatory plug were determined as indicators of inhibition of sperm and semen transports, respectively. Reproductive status of mated females was determined on gestation days 15-17. A low pregnancy rate associated with a decreased number of implants was observed in females that mated with the atropine-treated males. The average number of sperm in the vas deferens was increased in the atropine-treated males. The average seminal vesicle weight in the atropine-treated males was greater than that of controls. The copulatory plug weights were decreased in the atropine-treated males. These results suggest that inhibitions of sperm and semen transports from the vas deferens and seminal vesicle to the urethra during the process of emission result in reduced male fertility in rats.
Danshina, Polina V.; Geyer, Christopher B.; Dai, Qunsheng; Goulding, Eugenia H.; Willis, William D.; Kitto, G. Barrie; McCarrey, John R.; Eddy, E.M.; O'Brien, Deborah A.
Phosphoglycerate kinase 2 (PGK2), an isozyme that catalyzes the first ATP-generating step in the glycolytic pathway, is encoded by an autosomal retrogene that is expressed only during spermatogenesis. It replaces the ubiquitously expressed phosphoglycerate kinase 1 (PGK1) isozyme following repression of Pgk1 transcription by meiotic sex chromosome inactivation during meiotic prophase and by postmeiotic sex chromatin during spermiogenesis. The targeted disruption of Pgk2 by homologous recombination eliminates PGK activity in sperm and severely impairs male fertility, but does not block spermatogenesis. Mating behavior, reproductive organ weights (testis, excurrent ducts, and seminal vesicles), testis histology, sperm counts, and sperm ultrastructure were indistinguishable between Pgk2−/− and wild-type mice. However, sperm motility and ATP levels were markedly reduced in males lacking PGK2. These defects in sperm function were slightly less severe than observed in males lacking glyceraldehyde-3-phosphate dehydrogenase, spermatogenic (GAPDHS), the isozyme that catalyzes the step preceding PGK2 in the sperm glycolytic pathway. Unlike Gapdhs−/− males, the Pgk2−/− males also sired occasional pups. Alternative pathways that bypass the PGK step of glycolysis exist. We determined that one of these bypass enzymes, acylphosphatase, is active in mouse sperm, perhaps contributing to phenotypic differences between mice lacking GAPDHS or PGK2. This study determined that PGK2 is not required for the completion of spermatogenesis, but is essential for sperm motility and male fertility. In addition to confirming the importance of the glycolytic pathway for sperm function, distinctive phenotypic characteristics of Pgk2−/− mice may provide further insights into the regulation of sperm metabolism. PMID:19759366
Danshina, Polina V; Geyer, Christopher B; Dai, Qunsheng; Goulding, Eugenia H; Willis, William D; Kitto, G Barrie; McCarrey, John R; Eddy, E M; O'Brien, Deborah A
Phosphoglycerate kinase 2 (PGK2), an isozyme that catalyzes the first ATP-generating step in the glycolytic pathway, is encoded by an autosomal retrogene that is expressed only during spermatogenesis. It replaces the ubiquitously expressed phosphoglycerate kinase 1 (PGK1) isozyme following repression of Pgk1 transcription by meiotic sex chromosome inactivation during meiotic prophase and by postmeiotic sex chromatin during spermiogenesis. The targeted disruption of Pgk2 by homologous recombination eliminates PGK activity in sperm and severely impairs male fertility, but does not block spermatogenesis. Mating behavior, reproductive organ weights (testis, excurrent ducts, and seminal vesicles), testis histology, sperm counts, and sperm ultrastructure were indistinguishable between Pgk2(-/-) and wild-type mice. However, sperm motility and ATP levels were markedly reduced in males lacking PGK2. These defects in sperm function were slightly less severe than observed in males lacking glyceraldehyde-3-phosphate dehydrogenase, spermatogenic (GAPDHS), the isozyme that catalyzes the step preceding PGK2 in the sperm glycolytic pathway. Unlike Gapdhs(-/-) males, the Pgk2(-/-) males also sired occasional pups. Alternative pathways that bypass the PGK step of glycolysis exist. We determined that one of these bypass enzymes, acylphosphatase, is active in mouse sperm, perhaps contributing to phenotypic differences between mice lacking GAPDHS or PGK2. This study determined that PGK2 is not required for the completion of spermatogenesis, but is essential for sperm motility and male fertility. In addition to confirming the importance of the glycolytic pathway for sperm function, distinctive phenotypic characteristics of Pgk2(-/-) mice may provide further insights into the regulation of sperm metabolism.
Zhang, Yanjie; Mu, Huawei; Lau, Stanley C K; Zhang, Zhifeng; Qiu, Jian-Wen
Cataloging the sperm proteome of an animal can improve our understanding of its sperm-egg interaction and speciation, but such data are available for only a few free-spawning invertebrates. This study aimed to identify the sperm proteome of Mytilus galloprovincialis, a free-spawning marine mussel. We integrated public transcriptome datasets by de novo assembly, and applied SDS-PAGE coupled LC-MS/MS analysis to profile the sperm proteome, resulting in the identification of 550 proteins. Comparing the homologous sperm protein coding genes between M. galloprovincialis and its closely related species M. edulis revealed that fertilization proteins have the highest mean nonsynonymous substitution rate (Ka/Ks = 0.62) among 11 functional groups, consistent with previous reports of positive selection of several fertilization proteins in Mytilus. Moreover, 78 sperm proteins in different functional groups have Ka/Ks values > 0.5, indicating the presence of many candidate sperm proteins for further analysis of rapid interspecific divergence. The MS data are available in ProteomeXchange with the identifier PXD001665.
Kosman, E T; Levitan, D R
Proteins expressed on the surface of sperm and egg mediate gametic compatibility and these proteins can be subject to intense positive selection. In this review, we discuss what is known about the patterns of adaptive evolution of gamete recognition proteins (GRPs). We focus on species that broadcast eggs and sperm into the environment for external fertilization, as the ease of observing and manipulating gamete interactions has allowed for greater advances in the understanding of GRP evolution, uncomplicated by confounding behavioral and physiological components that offer alternative evolutionary targets in internal fertilizers. We discuss whether interspecific mechanisms, such as selection to avoid fertilization between species (reinforcement selection), or intraspecific mechanisms, such as selection to increase (or decrease) the affinity between eggs and sperm based on the intensity of sperm competition, may be responsible for the pattern of GRP evolution observed. Variation in these proteins appears to influence gametic compatibility; GRP divergence among species is a better predictor of hybrid fertilization than neutral genetic markers and GRP variation within species predicts reproductive success among individuals within a population. Evidence suggests that sperm competition may play a large role in the evolution of gametic compatibility.
Fertility of boar spermatozoa is changed after ejaculation in vivo and in vitro. During processing for in vitro fertilization (IVF), although spermatozoa are induced capacitation, resulting in a high penetration rate, persistent obstacle of polyspermic penetration is still observed with a high incidence. For artificial insemination (AI), we still need a large number of spermatozoa and lose a majority of those in the female reproductive tract. Fertility of cryopreserved boar spermatozoa is still injured through freezing and thawing process. In the present brief review, factors affecting fertility of boar sperm during IVF, AI and cryopreservation are discussed in the context of discovering methodologies to improve it.
Love, C C; Kenney, R M
The relationship between fertility and susceptibility of sperm DNA to denaturation was determined in a group of 84 actively breeding, clinically fertile stallions. Susceptibility of DNA to denaturation was determined using the sperm chromatin structure assay (SCSA). The SCSA measures, mean of alpha-t (mean alpha t), standard deviation of alpha-t (SD alpha t), and the COMP of alpha-t (cells outside the main population)] were significantly correlated with the percentage seasonal pregnancy rate (SPR; mean alpha t, r = -0.24, P < or = 0.05; % COMP alpha t, r = -0.27, P < or = 0.05); percentage pregnant per first cycle (FCP; SD alpha t, r = -0.30, P < or = 0.01; % COMP alpha t, r = -0.42, P < or = 0.0001); and the percentage pregnant per cycle (PC; mean alpha t, r = -0.31, P < or = 0.01; SD alpha t, r = -0.32, P < or = 0.01; % COMP alpha t, r = -0.41, P < or = 0.0001). This study describes detectable intrinsic variation in sperm chromatin structure among fertile stallions (SPR, mean = 83%; FCP, mean = 58%; PC, mean = 57%) in an active breeding population (number of mares bred/stallion/year, mean = 37), in the absence of overt reproductive abnormalities and apparent diseases such that an increase in the susceptibility of sperm DNA to denaturation is associated with reduced fertility, both in terms of efficiency of reproduction (FCP and PC) and seasonal pregnancy rate (SPR). Both COMP alpha t and mean alpha t were useful indicators of fertility, with COMP alpha t being the only SCSA value able to identify mean differences between fertility groupings for SPR and FCP, and overall it was the most reliable indicator of fertility in this group of stallions. The SCSA is able to evaluate a compartment of the spermatozoa which is different from that of traditional tests for sperm quality such as motility and morphology.
Lee, In-Kyoung; Lee, Sang-Myeong
Davallialactone (DAVA) is a hispidin analogue derived from the medicinal fungus Phellinus baumii. We examined the effect of DAVA on in vitro fertilization (IVF) of pigs. Boar spermatozoa were incubated in fertilization medium with varying concentrations of DAVA, then sperm motility and reactive oxygen species (ROS) level were evaluated. Higher sperm motility was found following the addition of 0.5 or 1 µM DAVA after incubation than addition of other concentrations or controls. ROS level decreased significantly with the addition of DAVA. The rate of normal fertilization was higher in the presence of 1 µM DAVA (65.1%) than were those of other concentrations or controls (45.4~59.4%), and the highest total fertilization rate (mono- and polyspermic oocytes) was observed at 1 µM DAVA (83%). In conclusion, addition of DAVA to fertilization medium improved sperm motility, and reduced ROS level so as to potentially improve sperm-oocyte binding in IVF, suggesting the potential of a compound isolated from mushrooms in assisted reproductive technology for humans and animals. PMID:27103855
Gallego, V; Cavalcante, S S; Fujimoto, R Y; Carneiro, P C F; Azevedo, H C; Maria, A N
Fish tambaqui (Colossoma macropomum) is the native Brazilian fish with the highest agricultural production under intensive aquaculture in South America. However, the decrease in the genetic variability in fish farms has become necessary the improvement of cryopreservation process through new statistical studies of spermatozoa (like subpopulation studies). The evaluation of the kinetic data obtained with a computer-assisted sperm analysis system, applying a two-step cluster analysis, yielded in tambaqui three different subpopulations in fresh sperm: SP1, considered as a slow nonlinear subpopulation; SP2, considered as a fast nonlinear subpopulation, and finally; SP3, considered as a fast linear subpopulation. For cryopreserved sperm, the cluster analysis yielded only two sperm subpopulations: SP1', considered as a slow nonlinear subpopulation and SP2', which seemed to be an intermediate subpopulation (showing medium motility and velocity values) merged from SP2 and SP3 obtained from fresh sperm. Coefficients of correlation (r) and determination (r(2)) between the sperm subpopulations from fresh sperm and the fertilization rates were calculated, and SP2 and SP3 (the fast-spermatozoa subpopulations) showed a high-positive correlation with the fertilization rates (r = 0.93 and 0.79, respectively). In addition, the positive significant correlations found in curvilinear velocity (r = 0.78), straight line velocity (r = 0.57), and average velocity (r = 0.75) indicate that sperm kinetic features seem to be a key factor in the fertilization process in tambaqui, as occur in other fish species.
Wandernoth, Petra M; Mannowetz, Nadja; Szczyrba, Jaroslaw; Grannemann, Laura; Wolf, Anne; Becker, Holger M.; Sly, William S.; Wennemuth, Gunther
HCO3− is a key factor in the regulation of sperm motility. High concentrations of HCO3− in the female genital tract induce an increase in sperm beat frequency, which speeds progress of the sperm through the female reproductive tract. Carbonic anhydrases (CA), which catalyze the reversible hydration of CO2 to HCO3−, represent potential candidates in the regulation of the HCO3− homeostasis in sperm and the composition of the male and female genital tract fluids. We show that two CA isoforms, CAII and CAIV, are distributed along the epididymal epithelium and appear with the onset of puberty. Expression analyses reveal an up-regulation of CAII and CAIV in the different epididymal sections of the knockout lines. In sperm, we find that CAII is located in the principal piece, whereas CAIV is present in the plasma membrane of the entire sperm tail. CAII and CAIV single knockout animals display an imbalanced HCO3− homeostasis, resulting in substantially reduced sperm motility, swimming speed, and HCO3−-enhanced beat frequency. The CA activity remaining in the sperm of CAII- and CAIV-null mutants is 35% and 68% of that found in WT mice. Sperm of the double knockout mutant mice show responses to stimulus by HCO3− or CO2 that were delayed in onset and reduced in magnitude. In comparison with sperm from CAII and CAIV double knockout animals, pharmacological loss of CAIV in sperm from CAII knockout animals, show an even lower response to HCO3−. These results suggest that CAII and CAIV are required for optimal fertilization. PMID:26487715
When intact Arbacia punctulata spermatozoa are exposed to solubilized egg jelly, the electrophoretic mobility of an abundant sperm flagellar membrane protein changes from an apparent molecular mass of 160 kDa to 150 kDa. A. punctulata spermatozoa can be labeled in vivo with /sup 32/P-labeled cells it was demonstrated that the mobility shift of the 160-kDa protein is due to dephosphorylation. The peptide resact (Cys-Val-Thr-Gly-Ala-Pro-Gly-Cys-Val-Gly-Gly-Gly-Arg-Leu-NH/sub 2/) is the component of egg jelly which is responsible for inducing the dephosphorylation. The 160/150-kdal sperm membrane protein has been purified to homogeneity by affinity chromatography on concanavalin A-agarose, and identified as sperm guanylate cyclase. The enzymatic activity of the guanylate cyclase is tightly coupled to its phosphorylation state. Resact has been shown to act as a potent chemoattractant for A. punctulata spermatozoa. The chemotactic response is concentration-dependent, is abolished by pretreatment of the spermatozoa with resact, and shows an absolute requirement for external calcium. This work represents the first demonstration of animal sperm chemotaxis in response to a precisely-defined molecule of egg origin. The results established a new, biologically meaningful function for resact, and may implicate sperm guanylate cyclase and cGMP in flagellar function and the chemotactic response.
Cherr, Gary N; Morisawa, Masaaki; Vines, Carol A; Yoshida, Kaoru; Smith, Edmund H; Matsubara, Takahiro; Pillai, Murali C; Griffin, Frederick J; Yanagimachi, Ryuzo
Sperm of the Pacific herring are immotile at spawning. Two egg-derived molecules are capable of initiating sperm motility. One is herring sperm activating protein(s) (HSAPs) and the other is sperm motility initiation factor (SMIF). These two motility initiators differ in their location and association with the chorion, and in their isoelectric points and molecular weights. In this study we have investigated the roles of these two inducers with respect to motility and fertilization. Using computer analysis of sperm motility, we found that HSAPs, as well as the C-terminal HSAPs peptide, elicit a linear motility pattern, while SMIF induced a highly circular and asymmetric pattern. HSAPs induced a two-fold increase in intracellular calcium, whereas SMIF induced a four-fold increase of motility initiation. SMIF-exposed sperm, preloaded with BAPTA-AM, showed a more linear motility and this motility trajectory decreased with their fertilizing capability. The difference in intracellular calcium levels between HSAPs and SMIF is consistent with the observed linear and circular motility. In the absence of SMIF, HSAPs do not support fertilization. Fertilization is rescued in these experiments if SMIF is reintroduced. We propose that diffusible HSAPs are not essential for fertilization, but enhance sperm-egg collisions via linear motility. SMIF, which is bound to the micropylar region of the chorion, is required for fertilization and induces circular motility that is a prerequisite for sperm to enter the micropylar canal and fertilize the egg.
Jansen, Vera; Alvarez, Luis; Balbach, Melanie; Strünker, Timo; Hegemann, Peter; Kaupp, U Benjamin; Wachten, Dagmar
Optogenetics is a powerful technique to control cellular activity by light. The light-gated Channelrhodopsin has been widely used to study and manipulate neuronal activity in vivo, whereas optogenetic control of second messengers in vivo has not been examined in depth. In this study, we present a transgenic mouse model expressing a photoactivated adenylyl cyclase (bPAC) in sperm. In transgenic sperm, bPAC mimics the action of the endogenous soluble adenylyl cyclase (SACY) that is required for motility and fertilization: light-stimulation rapidly elevates cAMP, accelerates the flagellar beat, and, thereby, changes swimming behavior of sperm. Furthermore, bPAC replaces endogenous adenylyl cyclase activity. In mutant sperm lacking the bicarbonate-stimulated SACY activity, bPAC restored motility after light-stimulation and, thereby, enabled sperm to fertilize oocytes in vitro. We show that optogenetic control of cAMP in vivo allows to non-invasively study cAMP signaling, to control behaviors of single cells, and to restore a fundamental biological process such as fertilization. DOI: http://dx.doi.org/10.7554/eLife.05161.001 PMID:25601414
Sasanami, Tomohiro; Sugiura, Kenichi; Tokumoto, Toshinobu; Yoshizaki, Norio; Dohra, Hideo; Nishio, Shunsuke; Mizushima, Shusei; Hiyama, Gen; Matsuda, Tsukasa
At the time of fertilization, the extracellular matrix surrounding avian oocytes, termed the perivitelline membrane (pvm), is hydrolyzed by a sperm-borne protease, although the actual protease that is responsible for the digestion of the pvm remains to be identified. Here, we show evidence that the ubiquitin-proteasome system is functional in the fertilization of Japanese quail. The activities for the induction of the acrosome reaction and binding to ZP3 as revealed by ligand blotting of purified serum ZP1 are similar to those of pvm ZP1. Western blot analysis of purified ZP1 and ZP3 by the use of the anti-ubiquitin antibody showed that only pvm ZP1 was reactive to the antibody. In vitro penetration assay of the sperm on the pvm indicated that fragments of ZP1 and intact ZP3 were released from the pvm. Western blot analysis using the anti-20S proteasome antibody and ultrastructural analysis showed that immunoreactive proteasome was localized in the acrosomal region of the sperm. Inclusion of specific proteasome inhibitor MG132 in the incubation mixture, or depletion of extracellular ATP by the addition of apyrase, efficiently suppressed the sperm perforation of the pvm. These results demonstrate for the first time that the sperm proteasome is important for fertilization in birds and that the extracellular ubiquitination of ZP1 might occur during its transport via blood circulation.
Xu, Yong-Nan; Cui, Xiang-Shun; Sun, Shao-Chen; Jin, Yong-Xun; Kim, Nam-Hyung
The use of intracytoplasmic sperm injection (ICSI) in model animals is a powerful approach for the study of species-specific fertilization processes and multiploidy embryogenesis. In this study, we examined the fertilization process in mouse oocytes following injection of a single mouse or cat sperm, two mouse spermatozoa or mouse and cat spermatozoa. These treatments did not affect histone H3K9 acetylation or methylation, although the pattern of DNA methylation differed following the injection of cat sperm. Immunocytochemical staining revealed that sperm chromatin was normally incorporated with female mouse chromatin following any of the four injection scenarios. Furthermore, metaphase was successfully entered to reach a normal two-cell stage, and cell division could even persist to produce blastocyst stage embryos. In addition, both mouse and cat Pou5l and Nanog mRNA were expressed in the hybrid embryos. These results suggest that, although epigenetic modification of DNA is affected by the sperm injection treatment, fertilization and cleavage occur in a non-species-specific manner. In addition, despite abnormal division of the chromosomes, intra- and inter-species ICSI produced embryos that could develop into blastocysts.
Macfarlane, Christopher P; Hoysak, Drew J; Liley, N Robin; Gage, Matthew J G
Although theory and widespread evidence show that the evolution of egg size is driven primarily by offspring and maternal fitness demands, an additional explanation invokes sperm limitation as a selective force that could also influence egg size optima. Levitan proposed that constraints from gamete encounter in external fertilization environments could select for enlargement of ova to increase the physical size of the fertilization target. We test this theory using in vitro fertilization experiments in an externally fertilizing fish. Sockeye salmon (Onchorhyncus nerka) females show considerable between-individual variation in ovum size, and we explored the consequences of this natural variation for the fertilization success of individual eggs under conditions of sperm limitation. By engineering consistent conditions where in vitro fertilization rate was always intermediate, we were able to compare the sizes of fertilized and unfertilized eggs across 20 fertilization replicates. After controlling for any changes in volume through incubation, results showed that successfully fertilized eggs were significantly larger than the eggs that failed to achieve fertilization. Under conditions without sperm limitation, fertility was unaffected by egg size. Our findings therefore support Levitan's theory, demonstrating empirically that some element of egg size variation could be selected by fertilization demands under sperm limitation. However, further research on sperm limitation in natural spawnings is required to assess the selective importance of these results.
Maruyama, Shin-ya; Ito, Momoe; Ikami, Yuusuke; Okitsu, Yu; Ito, Chizuru; Toshimori, Kiyotaka; Fujii, Wataru; Yogo, Keiichiro
We previously identified solute carrier 22a14 (Slc22a14) as a spermatogenesis-associated transmembrane protein in mice. Although Slc22a14 is a member of the organic anion/cation transporter family, its expression profile and physiological role have not been elucidated. Here, we show that Slc22a14 is crucial for sperm motility and male fertility in mice. Slc22a14 is expressed specifically in male germ cells, and mice lacking the Slc22a14 gene show severe male infertility. Although the overall differentiation of sperm was normal, Slc22a14−/− cauda epididymal spermatozoa showed reduced motility with abnormal flagellar bending. Further, the ability to migrate into the female reproductive tract and fertilise the oocyte were also impaired in Slc22a14−/− spermatozoa. The abnormal flagellar bending was thought to be partly caused by osmotic cell swelling since osmotic challenge or membrane permeabilisation treatment alleviated the tail abnormality. In addition, we found structural abnormalities in Slc22a14−/− sperm cells: the annulus, a ring-like structure at the mid-piece–principal piece junction, was disorganised, and expression and localisation of septin 4, an annulus component protein that is essential for the annulus formation, was also impaired. Taken together, our results demonstrated that Slc22a14 plays a pivotal role in normal flagellar structure, motility and fertility in mouse spermatozoa. PMID:27811987
Kroft, Tim L; Gleason, Elizabeth J; L'Hernault, Steven W
Fertilization, the union of sperm and egg to form a new organism, is a critical process that bridges generations. Although the cytological and physiological aspects of fertilization are relatively well understood, little is known about the molecular interactions that occur between gametes. C. elegans has emerged as a powerful system for the identification of genes that are necessary for fertilization. C. elegans spe-42 mutants are sterile, producing cytologically normal spermatozoa that fail to fertilize oocytes. Indeed, male mating behavior, sperm transfer to hermaphrodites, sperm migration to the spermatheca, which is the site of fertilization and sperm competition are normal in spe-42 mutants. spe-42 mutant sperm make direct contact with oocytes in the spermatheca, suggesting that SPE-42 plays a role during sperm-egg interactions just prior to fertilization. No other obvious defects were observed in spe-42 mutant worms. Cloning and sequence analysis revealed that SPE-42 is a novel predicted 7-pass integral membrane protein with homologs in many metazoan species, suggesting that its mechanism of action could be conserved.
SPERM MOTILITY IN HSF1 KNOCKOUT MICE AFTER HEAT SHOCK IS ASSOCIATED WITH FERTILITY DEFICITS. L.F. Strader*, S.D. Perreault, J.C. Luft*, and D.J. Dix*. US EPA/ORD, Reproductive Toxicology Div., Research Triangle Park, NC
Heat shock proteins (HSPs) protect cells from environm...
LOCALIZATION, FERTILITY INHIBITION, AND EPITOPE MAPS USING ANTIBODIES TO THE SPERM PROTEIN SP22. GR Klinefelter1, JE Welch*1, HDM Moore*2, K Bobseine*1, J Suarez*1 ,N Roberts*1 ,R Zucker *1 1U.S. EPA, NHEERL, Reproductive Toxicology Division, RTP, NC and 2University of Sheffield...
Cryopreserved semen allows the use of single ejaculates for repeated analyses, potentially improving in vitro fertilization (IVF) consistency by eliminating inter-ejaculate variability observed with fresh semen. However, the freezing and thawing processes result in compromised sperm function and IVF...
Katz, Sigrid; Rouse, Greg W
Osedax is a genus of siboglinid annelids in which the females live on dead vertebrate bones on the seafloor. These females have a posterior end that lies within the bone and contains the ovarian tissue, as well as the “roots” involved with bone degradation and nutrition. The males are microscopic and live as “harems” in the lumen of the gelatinous tube that surrounds the female trunk, well away from the ovary. Females are known to spawn fertilized primary oocytes, suggesting internal fertilization. However, little is known about sperm transfer, sperm storage, or the location of fertilization, and the morphology of the female reproductive system has not been described and compared with the reproductive systems of other siboglinids. A 3D-reconstruction of the ovisac of Osedax showed ovarian tissue with multiple lobes and mature oocytes stored in a “uterus” before being released through the single oviduct. The oviduct emerges as a gonopore on the trunk and travels along the trunk to finally open to the seawater as a thin cylindrical tube among the crown of palps. Light and transmission electron microscopy of mature Osedax sperm revealed elongate heads consisting of a nucleus with helical grooves occupied by mitochondria. In contrast to other Siboglinidae, Osedax sperm are not packaged into spermatophores or spermatozeugmata, and Osedax females lack a discrete region for sperm storage. Transmission electron microscopy and fluorescence microscopy allowed detection of sperm associated with ovarian tissue of the female ovisac of four different Osedax species. This provides the first evidence for the site of internal fertilization in Osedax. A heart body was found in the circulatory system, as seen in other siboglinids and some other annelids. The possible presence of nephridia in the anterior ovisac region was also documented. These morphological features provide new insights for comparing the regionalization of Osedax females in relation to other siboglinids
Ala-Honkola, Outi; Manier, Mollie K; Lüpold, Stefan; Droge-Young, Elizabeth M; Collins, William F; Belote, John M; Pitnick, Scott
Mating between relatives usually decreases genetic quality of progeny as deleterious recessive alleles are expressed in inbred individuals. Inbreeding degrades sperm traits but its effects on sperm storage and fate within females are currently unknown. We quantified the relationship between the degrees of inbreeding relevant to natural populations (f=0, 0.25 and 0.50) and the number of sperm inseminated and stored, sperm swimming speed, long-term sperm viability while in storage, pattern of sperm precedence, mating latency, and offspring viability of female Drosophila melanogaster. The use of transgenic flies that have either red or green fluorescent sperm heads allowed us to distinguish two ejaculates in the female reproductive tract and facilitated quantification of sperm storage and use traits. We found no inbreeding depression in either long- or short-term sperm storage ability. The most inbred females exhibited significantly longer mating latency, which could be explained by males preferring to mate with outbred females. On the other hand, as no evidence for cryptic male choice in the form of ejaculate tailoring of sperm number was found, the most inbred females might just be less eager to mate. We also found no evidence that the degree of maternal inbreeding influenced offspring viability. Comparison with a contemporaneous study of male inbreeding consequences for ejaculate quality suggests that inbreeding depression is more severe in males than in females in our study population.
Kashir, Junaid; Deguchi, Ryusaku; Jones, Celine; Coward, Kevin; Stricker, Stephen A
Fertilization causes mature oocytes or eggs to increase their concentrations of intracellular calcium ions (Ca²⁺) in all animals that have been examined, and such Ca²⁺ elevations, in turn, provide key activating signals that are required for non-parthenogenetic development. Several lines of evidence indicate that the Ca²⁺ transients produced during fertilization in mammals and other taxa are triggered by soluble factors that sperm deliver into oocytes after gamete fusion. Thus, for a broad-based analysis of Ca²⁺ dynamics during fertilization in animals, this article begins by summarizing data on soluble sperm factors in non-mammalian species, and subsequently reviews various topics related to a sperm-specific phospholipase C, called PLCζ, which is believed to be the predominant activator of mammalian oocytes. After characterizing initiation processes that involve sperm factors or alternative triggering mechanisms, the spatiotemporal patterns of Ca²⁺ signals in fertilized oocytes or eggs are compared in a taxon-by-taxon manner, and broadly classified as either a single major transient or a series of repetitive oscillations. Both solitary and oscillatory types of fertilization-induced Ca²⁺ signals are typically propagated as global waves that depend on Ca²⁺ release from the endoplasmic reticulum in response to increased concentrations of inositol 1,4,5-trisphosphate (IP₃). Thus, for taxa where relevant data are available, upstream pathways that elevate intraoocytic IP3 levels during fertilization are described, while other less-common modes of producing Ca²⁺ transients are also examined. In addition, the importance of fertilization-induced Ca²⁺ signals for activating development is underscored by noting some major downstream effects of these signals in various animals.
Viveiros, A T M; Nascimento, A F; Orfão, L H; Isaú, Z A
Streaked prochilod (Prochilodus lineatus) is a freshwater fish inhabiting many South American rivers. The objective was to determine the effectiveness of coconut water (ACP), combined with methylglycol, as a freezing medium for streaked prochilod sperm. A secondary objective was to compare a computer-assisted sperm analyzer (CASA) system versus subjective microscropic examination as a means of assessing sperm motility. As a control, glucose and methylglycol was used, according to our previous study. Sperm diluted in each medium was loaded into 0.5 mL straws, frozen in liquid nitrogen vapor (in a dry shipper), and stored in liquid nitrogen (-196 degrees C). Half of the samples were evaluated for sperm motility, both subjectively and with CASA; the remainder were evaluated for fertility. There was no difference (P > 0.05) between subjective or CASA assessment of post-thaw sperm motility. Although sperm motility was higher in sperm cryopreserved in ACP (85%) than in glucose (75%), cryopreservation in either extender yielded similar fertilization rates (46-48%) and sperm velocities. There were positive correlations (r = 0.56-0.8) between all sperm velocities and fertilization rate. In conclusion, streaked prochilod sperm cryopreserved in glucose or ACP and methylglycol was fertile, and thus could be used for research or commercial settings. Furthermore, although the CASA system provided objective data regarding sperm motility, in the present study, subjective evaluation of sperm motility was practical and a good indication of sperm quality; it could readily be done by well-trained personnel under field or laboratory conditions.
Shimada, Kiyoshi; Ono, Tamao; Mizushima, Shusei
Intracytoplasmic sperm injection (ICSI) technology in birds has been hampered due to opacity of oocyte. We developed ICSI-assisted fertilization and gene transfer in quail. This paper reviews recent advances of our ICSI experiments. The oocyte retrieved from the oviduct and a quail sperm was injected into the oocyte under a stereomicroscope. The oocyte was cultured for 24h at 41°C under 5% CO2 in air. The fertilization and development was assessed by microscopic observation. The fertility rate ranged 12-18% and development varied from stage II to V in trials. To improve the fertility rate, phospholipase C (PLC) zeta was injected with a sperm. It was increased to 37-50%. Furthermore, injection of inositol trisphosphate increased to over 85%. Quail oocyte can be fertilized with chicken sperm and so can testicular elongated spermatid. To extend embryonic development, chicken eggshell was used as a surrogate culture at 37°C after the 24h incubation at 41°C under 5% CO2 in air. It survived up to 2days thereafter. Finally, gene transfer was attempted in quail egg. The sperm membrane was disrupted with Triton X-100 (TX-100) and was injected with PLCzeta cRNA and enhanced green fluorescent protein (EGFP) gene in oocyte. The GFP expression was evaluated at 24h incubation at 41°C under 5% CO2 in air in the embryos. While the expression was not detected in the control oocytes, the experimental treatment induced blastoderm development (44%) of the oocytes and 86% of blastoderm showed fluorescent emission. In addition, PCR analysis detected EGFP fragments in 50% of GFP-expressing blastoderm. Our ICSI method may be the first step toward the production of transgenic birds.
Fujiwara, Katsuyoshi; Kamoshita, Maki; Kato, Tsubasa; Ito, Junya; Kashiwazaki, Naomi
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.
Jiang, X-H; Yie, S-M; Zhen, X; Den, Y-L; Liang, X; Hu, X; Li, L-M; Li, Q-J; Cao, S; Lu, H
This study is to explore whether YGW has an impact on sperm fertilising ability in mice. Twenty male mice were randomly divided into two groups. In vivo experiments, one group of animals were orally administrated with YGW decoction and another group administered with saline for 14 days. Afterwards, the animals were mated with their female partners. Percentages of retrieved zygotes were then compared. In vitro experiments, in vitro fertilisation (IVF) assay, sperm acrosome reaction and acrosin activity were used to compare sperm fertilising ability between the two groups. The YGW-treated group had a significantly higher percentage of zygotes than the saline controls (P = 0.005). The IVF rates induced by spermatozoa from the herb-treated mice were also significantly higher than those from the control animals (P = 0.015). The sperm acrosin activity of the herb-treated group was significantly higher than that of the saline-treated group (P = 0.048), although there was no significant difference in testicular weight, sperm count and sperm motility. These data suggest that YGW decoction has a significant effect on normal sperm fertilising ability both in vivo and in vitro, which may be due to, at least in part, increments in the sperm acrosin activity.
Judycka, Sylwia; Ciereszko, Andrzej; Dobosz, Stefan; Zalewski, Tomasz; Dietrich, Grzegorz J
Masculinized females, also called neomales or sex-reversed females have a male phenotype but retain the female genotype (XX). Therefore, all spermatozoa produced in their functional testes carry an X chromosome, which is desired for the production of all-female rainbow trout populations. Semen of sex-reversed female rainbow trout is of low quality and in vitro maturation is required, which includes dilution of sperm suspensions with specially formulated maturation solutions. The aim of this study was to determine the effect of dilution in different maturation media on sperm quality (sperm motility characteristics and fertilizing capacity) of frozen/thawed sperm of sex-reversed female rainbow trout. The effect of time of post-thaw storage (0, 15, 60 and 120min) on semen quality was also tested. Sperm motility parameters and fertilization rate at the eyed and hatching stages were assessed for post-thaw semen diluted in different media. The cryopreservation procedure resulted in high post-thaw sperm motility of about 57% and did not differ from fresh semen. Unexpectedly, maturation media decreased sperm activation capacity immediately after dilution; however, sperm motility increased over time. Fertilization rates of frozen/thawed semen were high (71-87%) and did not differ significantly between experimental variants at any of tested periods of storage. Our results demonstrated that the effect of the maturation media on frozen/thawed sperm is different from that of fresh sperm. The progressive increase in post-thaw sperm motility in maturation media can potentially be applied to routine hatchery practice.
Aydin, Halil; Sultana, Azmiri; Li, Sheng; Thavalingam, Annoj; Lee, Jeffrey E.
Fertilization is an essential biological process in sexual reproduction and comprises a series of molecular interactions between the sperm and egg1,2. The fusion of haploid spermatozoon and oocyte is the culminating event in mammalian fertilization, enabling the creation of a new genetically distinct diploid organism3,4. The merger of two gametes is achieved through a two-step mechanism where the sperm Izumo1 on the equatorial segment of the acrosome-reacted sperm recognizes its receptor Juno, on the egg surface4–6. This is followed by the fusion of two plasma membranes. Izumo1 and Juno proteins are indispensable for fertilization as constitutive knockout of either Izumo1 or Juno result in mice that are healthy but infertile5,6. Despite their central importance in reproductive medicine, the molecular architectures and the details of their functional roles in fertilization are not known. Here, we present the crystal structures of the human Izumo1 and Juno in unbound and bound conformations. The human Izumo1 structure exhibits a distinct boomerang shape and provides the first structural insights into the Izumo family of proteins7. Human Izumo1 forms a high-affinity complex with Juno and undergoes a major conformational change within its N-terminal domain upon binding to the egg-surface receptor. Our results provide new insights into the molecular basis of sperm-egg recognition, cross-species fertilization, and barrier to polyspermy, thus promising benefits for the rational development of novel non-hormonal contraceptives and fertility treatments for humans and other species of mammals. PMID:27309818
Xia, Jigang; Niu, Cuijuan
Perfluorooctane sulfonate (PFOS) has emerged as one of the most concerning contaminants in recent years. This study aimed to investigate the acute toxicity effect of PFOS on sperm viability, kinematics and fertilization success in zebrafish (Danio rerio). Sperm were activated in aqueous media containing a range of PFOS concentrations (0, 0.09, 0.9 and 9 mg/L). Viabilities and kinematics of the sperm exposed to different PFOS treatments were assessed via computer-assisted sperm analysis (CASA) at 20, 40 60 and 80 s after activation. PFOS exposure decreased the percentage of motile sperm, the curvilinear velocity (VCL), and the mean angular displacement (MAD) of spermatozoa, but showed no influence on the straight-line velocity (VSL) or the angular path velocity (VAP). Furthermore, a significant decrease in fertilization success was observed in spermatozoa that were exposed to 0.9 mg/L PFOS or more. These findings indicate that PFOS pollution in natural aquatic environment may be a potential threaten to successful reproduction of fish.
Comparative Analysis of Mafriwal (Bos taurus × Bos indicus) and Kedah Kelantan (Bos indicus) Sperm Proteome Identifies Sperm Proteins Potentially Responsible for Higher Fertility in a Tropical Climate
Ashrafzadeh, Ali; Nathan, Sheila; Karsani, Saiful Anuar
The fertility of zebu cattle (Bos indicus) is higher than that of the European purebred (Bos taurus) and crossbred (Bos taurus × Bos indicus) cattle in tropical areas. To identify proteins related to the higher thermo-tolerance and fertility of Zebu cattle, this study was undertaken to identify differences in sperm proteome between the high fertile Malaysian indigenous zebu cattle (Kedah Kelantan) and the sub-fertile crossbred cattle (Mafriwal). Frozen semen from three high performance bulls from each breed were processed to obtain live and pure sperm. Sperm proteins were then extracted, and two-dimensional gel electrophoresis performed to compare proteome profiles. Gel image analysis identified protein spots of interest which were then identified by liquid chromatography mass spectrometry quadrupole time-of-flight (LC MS/MS Q-TOF). STRING network analysis predicted interactions between at least 20 of the identified proteins. Among the identified proteins, a number of motility and energy related proteins were present in greater abundance in Kedah Kelantan. Sperm motility evaluation by Computer Assisted Semen Analysis (CASA) confirmed significantly higher motility in Kedah Kelantan. While results from this study do identify proteins that may be responsible for the higher fertility of Kedah Kelantan, functional characterization of these proteins is warranted to reinforce our understanding of their roles in sperm fertility. PMID:23903046
Kekäläinen, Jukka; Soler, Carles; Veentaus, Sami; Huuskonen, Hannu
Many ejaculate traits show remarkable variation in relation to male social status. Males in disfavoured (subordinate) mating positions often invest heavily on sperm motility but may have less available resources on traits (e.g., secondary sexual ornaments) that improve the probability of gaining matings. Although higher investments in sperm motility can increase the relative fertilization success of subordinate males, it is unclear whether status-dependent differences in sperm traits could have any consequences for offspring fitness. We tested this possibility in whitefish (Coregonus lavaretus L.) by experimentally fertilizing the eggs of 24 females with the sperm of either highly-ornamented (large breeding tubercles, dominant) or less-ornamented (small tubercles, subordinate) males (split-clutch breeding design). In comparison to highly-ornamented individuals, less-ornamented males had higher sperm motility, which fertilized the eggs more efficiently, but produced embryos with impaired hatching success. Also offspring size and body condition were lower among less-ornamented males. Furthermore, sperm motility was positively associated with the fertilization success and offspring size, but only in highly-ornamented males. Together our results indicate that male investments on highly motile (fertile) sperm is not necessarily advantageous during later offspring ontogeny and that male status-dependent differences in sperm phenotype may have important effects on offspring fitness in different life-history stages. PMID:26389594
Kekäläinen, Jukka; Soler, Carles; Veentaus, Sami; Huuskonen, Hannu
Many ejaculate traits show remarkable variation in relation to male social status. Males in disfavoured (subordinate) mating positions often invest heavily on sperm motility but may have less available resources on traits (e.g., secondary sexual ornaments) that improve the probability of gaining matings. Although higher investments in sperm motility can increase the relative fertilization success of subordinate males, it is unclear whether status-dependent differences in sperm traits could have any consequences for offspring fitness. We tested this possibility in whitefish (Coregonus lavaretus L.) by experimentally fertilizing the eggs of 24 females with the sperm of either highly-ornamented (large breeding tubercles, dominant) or less-ornamented (small tubercles, subordinate) males (split-clutch breeding design). In comparison to highly-ornamented individuals, less-ornamented males had higher sperm motility, which fertilized the eggs more efficiently, but produced embryos with impaired hatching success. Also offspring size and body condition were lower among less-ornamented males. Furthermore, sperm motility was positively associated with the fertilization success and offspring size, but only in highly-ornamented males. Together our results indicate that male investments on highly motile (fertile) sperm is not necessarily advantageous during later offspring ontogeny and that male status-dependent differences in sperm phenotype may have important effects on offspring fitness in different life-history stages.
Schuel, H; Goldstein, E; Mechoulam, R; Zimmerman, A M; Zimmerman, S
Anandamide (arachidonylethanolamide) is an endogenous cannabinoid receptor agonist in mammalian brain. Sea urchin sperm contain a high-affinity cannabinoid receptor similar to the cannabinoid receptor in mammalian brain. (-)-delta 9-Tetrahydrocannabinol (THC), the primary psychoactive cannabinoid in marihuana, reduces the fertilizing capacity of sea urchin sperm by blocking the acrosome reaction that normally is stimulated by a specific ligand in the egg's jelly coat. We now report that anandamide produces effects similar to those previously obtained with THC in Strongylocentrotus purpuratus in reducing sperm fertilizing capacity and inhibiting the egg jelly-stimulated acrosome reaction. Arachidonic acid does not inhibit the acrosome reaction under similar conditions. The adverse effects of anandamide on sperm fertilizing capacity and the acrosome reaction are reversible. The receptivity of unfertilized eggs to sperm and sperm motility are not impaired by anandamide. Under conditions where anandamide completely blocks the egg jelly-stimulated acrosome reaction, it does not inhibit the acrosome reaction artificially initiated by ionomycin, which promotes Ca2+ influx, and nigericin, which activates K+ channels in sperm. These findings provide additional evidence that the cannabinoid receptor in sperm plays a role in blocking the acrosome reaction, indicate that anandamide or a related molecule may be the natural ligand for the cannabinoid receptor in sea urchin sperm, and suggest that binding of anandamide to the cannabinoid receptor modulates stimulus-secretion-coupling in sperm by affecting an event prior to ion channel opening. PMID:8052642
Hazzard, Karen C; Watkins-Chow, Dawn E; Garrett, Lisa J
In vitro fertilization (IVF) is used to produce mouse embryos for a variety of reasons. We evaluated the effect of the method of euthanasia on the fertilization rate in 2 different IVF protocols. Oocytes collected from C57BL/6J female mice euthanized by CO2 inhalation or cervical dislocation were used in IVF with fresh sperm from either wild-type or genetically engineered C57BL/6J. Compared with CO2 inhalation, cervical dislocation improved the resulting rate of fertilization by 18% in an IVF method using Cook media and by 13% in an IVF method using methyl-B cyclodextrin and reduced glutathione. The lower fertilization rate due to euthanasia by CO2 inhalation was accompanied by changes in blood pH and body temperature despite efforts to minimize temperature drops. In our hands, euthanasia by cervical dislocation improved fertilization rates and consequently reduced the number of egg-donor mice required.
Taberner, E; Morató, R; Mogas, T; Miró, J
An experiment was designed to study the interaction between fresh/frozen-thawed donkey spermatozoa and zona pellucida (ZP)-free bovine oocytes in an attempt to develop a model for assessing cryopreserved Catalonian donkey sperm function. Semen from five donkeys was collected using an artificial vagina. Sperm motility and viability were immediately assessed and the semen sample cryopreserved. Sperm viability and motility were then reassessed immediately after thawing. The motion characteristics of the fresh and frozen-thawed spermatozoa were determined using a computer-assisted sperm analysis system. In vitro-matured cow oocytes were inseminated with different percent live donkey sperm (high (>60%) or low (<40%) viability donkey sperm). After 18h of co-incubation, the oocytes were fixed, stained with 4',6-diamidino-2-phenylindole (DAPI) and examined for sperm penetration, the number of penetrated spermatozoa per oocyte, and male pronucleus formation. Frozen-thawed spermatozoa from high viability semen showed significantly lower VCL, VAP and mean ALH values than did high viability fresh spermatozoa. In contrast, frozen-thawed spermatozoa of low viability had significantly higher velocity values than fresh spermatozoa of low viability. A significant positive correlation (P<0.01) was detected between percentage fertilization and viability (r=0.84), and between percentage fertilization and certain CASA parameters (VAP, r=0.56; VCL, r=0.61 and mean ALH, r=0.68). Fresh or frozen-thawed high viability spermatozoa penetrated 90.1% and 85.4% of bovine oocytes respectively. Lower rates of penetration were observed for fresh and frozen-thawed low viability spermatozoa (34% and 22.5% respectively). The donkey spermatozoa were able to fuse with the oolema and even to decondense and form the male pronucleus (85-94%). Larger numbers of penetrated spermatozoa per oocyte were recorded when high viability sperm samples were used, whether fresh (3.02 vs. 1.12 for low viability sperm
Frijters, A C J; Mullaart, E; Roelofs, R M G; van Hoorne, R P; Moreno, J F; Moreno, O; Merton, J S
Until now it has been unclear to what extent the reduced fertility with sexed semen in the dairy industry is caused by too few sperm per AI dose, or by the effect of flow cytometric sorting, which is the established procedure for sexing semen. Therefore, we evaluated the effects of low sperm numbers per dose with and without sorting on non-return rates after 56 days (NRR 56); in addition, we evaluated the effects of bulls, in order to further optimize use of sexed semen. Based on results of using sexed semen from seven Holstein bulls, an overall numerical decline of 13.6% in NRR 56 was observed (P<0.05). About two-thirds of this decline (8.6%) was due to the low dose (P<0.05), and a third (5.0%) due to the process of sorting (P<0.05). The effect of low dosage and sorting differed among bulls. We observed a sex ratio of 91.6% females for sexed semen from the first 131 calves born. Currently the best way to increase fertility of sexed semen is by closely monitoring fertility so that the highest fertility bulls are used, and by improving farm animal management. However, to make substantial progress, more in depth studies are needed on the sexing technology, especially on aspects such as sorting procedures and sperm dosage.
Talevi, R; Campanella, C
The heterogeneity of the egg surface with respect to receptivity to sperm was investigated in Discoglossus pictus; in this species fertilization occurs only in an indentation called the dimple, at the center of the animal hemisphere. Following insemination sperm are seen in the outermost jelly layers and in the lens-shaped jelly plug, converging to the dimple center, D1. A fertilization potential (FP) is recorded 30 sec following insemination. About 30 min after fertilization, when fertilization cones can be detected easily, immotile sperm are found at the center of the cone, where 10 min later they accomplish penetration. After 15 min the cone regresses and the second polar body is extruded. In eggs where the plug was experimentally displaced with respect to the dimple, spermatozoa contacted the sides of the dimple and simple protrusions formed but not cones. Spermatozoa do not elicit a normal FP in these regions but small step depolarizations which may be followed by a gradual rise to a positive plateau potential. Such eggs do not develop. In the protrusions, sperm may be only partially incorporated and the unpenetrated portion appears to degenerate. We conclude that at least two regions exist in the dimple: D1, where the FP is triggered, cones are formed, sperm penetration is fully accomplished and development is initiated; and D2 + D3 where the electrical response is not a normal FP, cones do not form, total sperm penetration does not occur, and development is not initiated.
Bozhedomov, V A; Nikolaeva, M A; Ushakova, I V; Lipatova, N A; Bozhedomova, G E; Sukhikh, G T
Autoimmune reactions against the sperm cells play an ambiguous role in fertility impairment. The objective of this study was to characterize functional deficit of sperm conditioned by antisperm immune response in normozoospermic men. This was a multi-centric, cross-sectional, сase-control study. The study subjects were 1060 infertile normozoospermic men and 107 fertile men. The main outcome measures were clinical examination, semen analysis including MAR test for antisperm antibodies (ASA), computer-aided sperm analysis, acrosome reaction (AR) detected with flow cytometry, DNA fragmentation measured with sperm chromatin dispersion, reactive oxygen species (ROS) assessed using the luminol-dependent chemiluminescence method. 2% of the fertile men had MAR-IgG ≥ 50%, but all subjects with MAR-IgG>12% were outliers; 16% infertile men had MAR-IgG ≥ 50% (p<0.0001). There was a direct correlation between the infertility duration and MAR-IgG (R=0.3; р<0.0001). The ASA-positive infertile men had AR disorders 2.1 times more frequently (р<0.02), predominantly inductivity disorders. We found signs of hyperactivation proportionate to the ASA level (p<0.001). DNA fragmentation was more highly expressed and was 1.6 and 1.3 times more frequent compared with the fertile and the ASA-negative patients, respectively (p<0.001 and p<0.05). We found signs of oxidative stress (OS): ROS generation by washed ASA-positive spermatozoa was 3.7 times higher than in the fertile men (p<0.00001) and depended on the ASA levels (R=0.5; p<0.0001). The ASA correlation with ROS generation in native sperm was weak (R=0.2; р<0.001). We concluded that autoimmune reactions against spermatozoa are accompanied by a fertility decrease in normozoospermia. This results from AR and capacitation disorders and DNA fragmentation. The pathogenesis of sperm abnormalities in immune infertility is associated with the OS of spermatozoa.
MAKITA, Miho; UEDA, Mayuko; MIYANO, Takashi
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
Viet LINH, Nguyen; KIKUCHI, Kazuhiro; NAKAI, Michiko; TANIHARA, Fuminori; NOGUCHI, Junko; KANEKO, Hiroyuki; DANG-NGUYEN, Thanh Quang; MEN, Nguyen Thi; VAN HANH, Nguyen; SOMFAI, Tamas; NGUYEN, Bui Xuan; NAGAI, Takashi; MANABE, Noboru
Abstract Mitochondria are reported to be critical in in vitro maturation of oocytes and subsequent embryo development after fertilization, but their contribution for fertilization has not been investigated in detail. In the present study, we investigate the contribution of mitochondria to fertilization using reconstructed porcine oocytes by fusion of ooplasmic fragments produced by serial centrifugations (centri-fusion). Firstly, we evaluated the characteristics of ooplasmic fragments. Three types of fragments were obtained by centrifugation of porcine oocytes matured in vitro for 46 h: brownish (B), transparent (T) and large (L) fragments containing both B and T parts in a fragment. The production efficiencies of these types of fragments were 71.7, 91.0 and 17.8 fragments/100 oocytes, respectively. In experiments, L fragments were excluded because they contained both brownish and transparent components that were apparently intermediate between B and T fragments. Observations by confocal microscopy after staining with MitoTracker Red CMXRos® and transmission electron microscopy revealed highly condensed active mitochondria in B fragments in contrast to T fragments that contained only sparse organelles. We reconstructed oocytes by fusion of a karyoplast and two cytoplasts from B and T fragments (B and T oocytes, respectively). The B oocytes showed higher sperm penetration (95.8%) and male pronuclear formation rates (94.2%) by in vitro fertilization than T oocytes (66.7% and 50.0%, respectively). These results suggest that the active mitochondria in oocytes may be related to their ability for fertilization. PMID:23965685
McKnight, Katherine; Hoang, Hieu D; Prasain, Jeevan K; Brown, Naoko; Vibbert, Jack; Hollister, Kyle A; Moore, Ray; Ragains, Justin R; Reese, Jeff; Miller, Michael A
Environmental exposures affect gamete function and fertility, but the mechanisms are poorly understood. Here, we show that pheromones sensed by ciliated neurons in the Caenorhabditis elegans nose alter the lipid microenvironment within the oviduct, thereby affecting sperm motility. In favorable environments, pheromone-responsive sensory neurons secrete a transforming growth factor-β ligand called DAF-7, which acts as a neuroendocrine factor that stimulates prostaglandin-endoperoxide synthase [cyclooxygenase (Cox)]-independent prostaglandin synthesis in the ovary. Oocytes secrete F-class prostaglandins that guide sperm toward them. These prostaglandins are also synthesized in Cox knockout mice, raising the possibility that similar mechanisms exist in other animals. Our data indicate that environmental cues perceived by the female nervous system affect sperm function.
McKnight, Katherine; Hoang, Hieu D.; Prasain, Jeevan K.; Brown, Naoko; Vibbert, Jack; Hollister, Kyle A.; Moore, Ray; Ragains, Justin R.; Reese, Jeff; Miller, Michael A.
Environmental exposures impact gamete function and fertility, but the mechanisms are poorly understood. Here we show that pheromones sensed by ciliated neurons in the C. elegans nose alter the lipid microenvironment within the oviduct, thereby affecting sperm motility. In favorable environments, pheromone-responsive sensory neurons secrete a TGF-β ligand called DAF-7, which acts as a neuroendocrine factor that stimulates prostaglandin-endoperoxide synthase (Cox)-independent prostaglandin synthesis in the ovary. Oocytes secrete F class prostaglandins that guide sperm toward them. These prostaglandins are also synthesized in Cox knockout mice, raising the possibility that similar mechanisms exist in other animals. Our data indicate environmental cues perceived by the female nervous system affect sperm function. PMID:24833393
Nahiduzzaman, Md; Hassan, Md Mahbubul; Roy, Pankoz Kumar; Hossain, Md Akhtar; Hossain, Mostafa Ali Reza; Tiersch, Terrence R
A sperm cryopreservation protocol for the Indian major carp, Labeo calbasu, was developed for long-term preservation and artificial fertilization. Milt collected from mature male fish were placed in Alsever's solution (296mOsmolkg(-1)) to immobilize the sperm. Cryoprotectant toxicity was evaluated by motility assessment with dimethyl sulfoxide (DMSO) and methanol at 5, 10 and 15% concentrations. DMSO was more toxic at higher concentrations than methanol, and consequently 15% DMSO was excluded from further study. A one-step cooling protocol (from 5 to 80°C) with two cooling rates (5 and 10°C/min) was carried out in a computer-controlled freezer (FREEZE CONTROL(®) CL-3300; Australia). Based on post-thaw motility, the 10°C/min cooling rate with either 10% DMSO or 10% methanol yielded significantly higher (P=0.011) post-thaw motility than the other rate and cryoprotectant concentrations. Sperm thawed at 40°C for 15s and fresh sperm were used to fertilize freshly collected L. calbasu eggs and significant differences were observed (P=0.001) in percent fertilization between cryopreserved and fresh sperm as well as among different sperm-to-egg ratios (P=0.001). The highest fertilization and hatching rates were observed for thawed sperm at a sperm-to-egg ratio of 4.1×10(5):1. The cryopreservation protocol developed can facilitate hatchery operations and long-term conservation of genetic resources of L. calbasu.
Killifish (Fundulus heteroclitus) embryos from Piles Creek (PC), a polluted tidal creek near heavily industrialized Linden, New Jersey, are more tolerant to methylmercury (meHg) than embryos from a non-polluted area in Southampton, Long Island (LI), New York. This study was designed to determine whether tolerance existed in gametes and juvenile fish of these two populations. Exposure (2 min) of PC sperm to either 0.01 or 0.05 ppm meHg had no effect on fertilization and sperm motility, but exposure to Hg caused a significant reduction in fertilization and sperm motility, indicating that Hg was more toxic to PC sperm than meHg. However, exposure of LI sperm to 0.01 ppm meHg caused a significant reduction in fertilization and sperm motility. Exposure of LI sperm to 0.01 ppm Hg did not have any effect on fertilization success, indicating that Hg was less toxic than meHg for Li sperm. Exposure (20 min) of PC and LI eggs to higher concentrations of these toxicants showed similar results.
INHIBITION OF IN VITRO FERTILIZATION IN THE HAMSTER BY ANTIBODIES RAISED AGAINST THE RAT SPERM PROTEIN SP22. SC Jeffay*, SD Perreault, KL Bobseine*, JE Welch*, GR Klinefelter, US EPA, Research Triangle Park, NC.
SP22, a rat sperm membrane protein that is highly-correlated w...
Shojaei, H; Kroetsch, T; Wilde, R; Blondin, P; Kastelic, J P; Thundathil, J C
The objectives were to compare testicular physical characteristics and post-thaw sperm characteristics and their associations with fertility in Holstein bulls used for AI. Ten Holstein bulls (4-5 y old) were classified as either high-fertility (HF) or low-fertility (LF; n = 5 each), based on adjusted 56-d non-return rates [non-return rate (NRR); range (mean ± SD): 55.6 ± 4.6 to 71.8 ± 1.3%). Testicular physical characteristics were not significantly different between the two groups. Four ejaculates were collected from each bull and cryopreserved. Several indexes of sperm motion (based on computer-assisted sperm analysis) at post-thaw and post-swim-up were correlated with NRR. Sperm from HF bulls were in transition to a hyperactivated motility pattern, whereas those from LF bulls had only a forward progressive motility pattern. In HF vs LF bulls, there was a greater percentage of viable sperm after thawing (60.6 ± 9.7 vs 49.5 ± 8.0%, P < 0.05) and after swim-up (70.9 ± 11.0 vs 63.0 ± 8.8%, P < 0.01); these two end points were positively correlated with fertility (r = 0.45, P < 0.01 and r = 0.78; P < 0.01, respectively). Furthermore, in HF vs LF bulls, the ratio of sperm recovered after swim-up to viable sperm in post-thaw semen was higher (P < 0.001), and the proportion of moribund sperm expressed as a percentage of live sperm differed (12.6 ± 3.4 vs. 16.4 ± 3.1%, P < 0.001) and was negatively correlated (r = -0.33, P < 0.05) with fertility. In conclusion, fertility of Holstein bulls maintained in a commercial AI center was not predicted by testicular physical characteristics, but it was associated with differences in moribund sperm in the inseminate, as well as characteristics of sperm post-thaw and after swim-up.
Huang, Changjiang; Dong, Qiaoxiang; Walter, Ronald B; Tiersch, Terrence R
Sperm cryopreservation for fishes with internal fertilization is essentially unexplored although many species of these fishes are valuable biomedical research models. To explore methods for sperm cryopreservation within the live-bearing genus Xiphophorus, this study used X. helleri to evaluate the effects of cryoprotectant, osmotic pressure, cooling rate, equilibration time, and sperm-to-extender ratio. Sperm motility and survival duration after thawing showed significant differences among different cryoprotectants with the highest motility at 10 min after thawing obtained with 14% glycerol. With subsequent use of 14% glycerol as the cryoprotectant, the highest motility after thawing was observed with Hanks' balanced salt solution (HBSS) at 300 mOsmol/kg. Samples cooled from 5 to -80 degrees C at 20 degrees C/min yielded the highest post-thaw motility although no significant difference was found in the first 4h after thawing for cooling rates across the range of 20-35 degrees C/min. Evaluation of equilibration time revealed no significant difference between 20 min and 2h, but the highest motility at 10 min after thawing was found with a 20-min equilibration. Dilution ratios of sperm-to-extender at 1:20, 1:60, and 1:120 showed no significant differences in motility and survival duration after thawing, but the dilution of sperm solutions with HBSS (320 mOsmol/kg) immediately after thawing reduced the decline of sperm motility, and significantly prolonged the survival duration. Based on these findings, the highest average sperm motility (77%) at 10 min after thawing was obtained when sperm were suspended in HBSS at 300 mOsmol/kg with 14% glycerol as cryoprotectant, diluted at a ratio of sperm to HBSS-glycerol of 1:20, equilibrated for 10 min, cooled at 20 degrees C/min from 5 to -80 degrees C before being plunged in liquid nitrogen, and thawed in a 40 degrees C water bath for 7s. If diluted immediately after thawing, sperm frozen by the protocol above retained
Beek, J; Nauwynck, H; Appeltant, R; Maes, D; Van Soom, A
Serine proteases are involved in mammalian fertilization. Inhibitors of serine proteases can be applied to investigate at which point these enzymes exert their action. We selected two serine protease inhibitors, 4-(2-aminoethyl)benzenesulfonyl fluoride hydrochloride (AEBSF, 100 μM) and soybean trypsin inhibitor (STI, 5 μM) from Glycine max, via previous dose-response IVF experiments and sperm toxicity tests. In the present study, we evaluated how these inhibitors affect porcine fertilization in vitro as calculated on total fertilization rate, polyspermy rate, and the sperm number per fertilized oocyte of cumulus-intact, cumulus-free, and zona-free oocytes. In the control group (no inhibitor), these parameters were 86%, 49%, and 2.2 for cumulus-intact oocytes and 77%, 43%, and 2.2 for cumulus-free oocytes (6-hour gamete incubation period, 1.25 × 10(5) spermatozoa/mL). 4-(2-Aminoethyl)benzenesulfonyl fluoride hydrochloride and STI significantly reduced total fertilization and polyspermy rate in cumulus-intact and cumulus-free oocytes (P < 0.05). Total fertilization rates were respectively 65% and 53% (AEBSF) and 36% and 17% (STI). Inhibition rates were higher in cumulus-free oocytes than in cumulus-intact oocytes, indicating that inhibitors exerted their action after sperm passage through the cumulus. 4-(2-Aminoethyl)benzenesulfonyl fluoride hydrochloride but not STI reduced sperm binding to the ZP. The acrosome reaction was significantly inhibited by both inhibitors. Only 40.4% (AEBSF) and 11.4% (STI) of spermatozoa completed a calcium-induced acrosome reaction compared to 86.7% of spermatozoa in the control group. There was no effect on sperm binding or fertilization parameters in zona-free oocytes. In conclusion, sperm-zona binding and acrosome reaction were inhibited by serine protease inhibitors during porcine IVF.
Yi, Y-J; Zimmerman, S W; Manandhar, G; Odhiambo, J F; Kennedy, C; Jonáková, V; Maňásková-Postlerová, P; Sutovsky, M; Park, C-S; Sutovsky, P
Protein ubiquitination is a stable, covalent post-translational modification that alters protein activity and/or targets proteins for proteolysis by the 26S proteasome. The E1-type ubiquitin-activating enzyme (UBA1) is responsible for ubiquitin activation, the initial step of ubiquitin-protein ligation. Proteasomal proteolysis of ubiquitinated spermatozoa and oocyte proteins occurs during mammalian fertilization, particularly at the site of sperm acrosome contact with oocyte zona pellucida. However, it is not clear whether the substrates are solely proteins ubiquitinated during gametogenesis or if de novo ubiquitination also occurs during fertilization supported by ubiquitin-activating and -conjugating enzymes present in the sperm acrosome. Along this line of inquiry, UBA1 was detected in boar sperm-acrosomal extracts by Western blotting (WB). Immunofluorescence revealed accumulation of UBA1 in the nuclei of spermatogonia, spermatocytes and spermatids, and in the acrosomal caps of round and elongating spermatids. Thiol ester assays utilizing biotinylated ubiquitin and isolated sperm acrosomes confirmed the enzymatic activity of the resident UBA1. A specific UBA1 inhibitor, PYR-41, altered the remodelling of the outer acrosomal membrane (OAM) during sperm capacitation, monitored using flow cytometry of fluorescein isothiocyanate-conjugated peanut agglutinin (FITC-PNA). Although viable and motile, the spermatozoa capacitated in the presence of PYR-41, showed significantly reduced fertilization rates during in vitro fertilization (IVF; p < 0.05). Similarly, the fertilization rate was lowered by the addition of PYR-41 directly into fertilization medium during IVF. In WB, high Mr bands, suggestive of protein ubiquitination, were detected in non-capacitated spermatozoa by antibodies against ubiquitin; WB with anti-phosphotyrosine antibodies and antibodies against acrosomal proteins SPINK2 (acrosin inhibitor) and AQN1 (spermadhesin) revealed that the capacitation
Swann, Karl; Lai, F Anthony
A series of intracellular oscillations in the free cytosolic Ca(2+) concentration is responsible for activating mammalian eggs at fertilization, thus initiating embryo development. It has been proposed that the sperm causes these Ca(2+) oscillations after membrane fusion by delivering a soluble protein into the egg cytoplasm. We previously identified sperm-specific phospholipase C (PLC)-ζ as a protein that can trigger the same pattern of Ca(2+) oscillations in eggs seen at fertilization. PLCζ appears to be the elusive sperm factor mediating egg activation in mammals. It has potential therapeutic use in infertility treatments to improve the rate of egg activation and early embryo development after intra-cytoplasmic sperm injection. A stable form of recombinant human PLCζ could be a prototype for use in such in vitro fertilization (IVF) treatments. We do not yet understand exactly how PLCζ causes inositol 1,4,5-trisphosphate (InsP3) production in eggs. Sperm PLCζ is distinct among mammalian PI-specific PLCs in that it is far more potent in triggering Ca(2+) oscillations in eggs than other PLCs, but it lacks a PH domain that would otherwise be considered essential for binding to the phosphatidylinositol 4,5-bisphosphate (PIP2) substrate. PLCζ is also unusual in that it does not appear to interact with or hydrolyse plasma membrane PIP2. We consider how other regions of PLCζ may mediate its binding to PIP2 in eggs and how interaction of PLCζ with egg-specific factors could enable the hydrolysis of internal sources of PIP2.
Dong, Hong-Jun; Wu, De; Xu, Sheng-Yu; Li, Qiang; Fang, Zheng-Feng; Che, Lian-Qiang; Wu, Cai-Mei; Xu, Xue-Yu; Lin, Yan
The aim of this study was to evaluate the effects of dietary supplementation with amino acids on sperm quality and fertility rates after insemination with boar semen. Twelve Yorkshire boars were paired by age and allocated to one of two dietary treatments composed of total lysine levels of 0.64% (T1) and 0.96% (T2), with the lysine: methionine: threonine: tryptophan: valine ratio in the diets set to 100:27:73:19:69 through the addition of synthetic amino acids. Semen was collected twice weekly (phase 1, 1-12 wk); every other day (phase 2, 13-16 wk); twice weekly (phase 3, 17-26 wk); and daily (phase 4, 27-28 wk). Semen was collected from boars during phase 3 and used to inseminate 64 multiparous sows. Our results showed that sperm concentration and total sperm cells were greater in boars in T2 than in boars in T1 in phases 2 and 4 (P<0.05). Sperm motility parameters, morphologically normal sperm, and acrosome integrity in T2 boars were greater than those in T1 boars (P<0.05) during the experiment. Free amino acid concentrations in seminal plasma increased in T2 boars (P<0.05). Furthermore, sows inseminated with semen collected from T2 boars gave birth to more live piglets than those inseminated with semen collected from T1 boars (P=0.04). In conclusion, supplementation of boar diet with amino acids improves sperm quality, and subsequently increases fertilization capacity and the number of live piglets.
McEleny, Kevin; Cheetham, Tim; Quinton, Richard
Advances in surgical sperm retrieval have greatly increased the chances of men with Klinefelter syndrome achieving biological paternity. Despite this, the vast majority of attempts to achieve fertility by using extracted gametes to fertilize eggs in vitro do not result in viable pregnancies. A powerful obstacle to success lies with the natural history of seminiferous tubule and germ cell function in Klinefelter syndrome, which typically peak (and thereafter steeply decline) up to a decade before most individuals would be contemplating paternity. Herein we discuss, in relation to a real clinical case, both the exciting technical advances surgical sperm retrieval and the logistic and ethical factors that, in practice, may act to limit their successful application.
Vieytes, A L; Cisale, H O; Ferrari, M R
The relationships between the fertility and nuclear morphology, chromatin maturity and chromatin condensation of the sperm of three bulls with a calving rate over a year of more than 65 per cent, four bulls with a calving rate between 65 per cent and 35 per cent, and three bulls with a calving rate of less than 35 per cent were studied. The sperm nuclei were stained with the Feulgen reaction, and chromatin condensation and maturation were evaluated in situ by staining with toluidine blue and acid aniline blue. Nuclear chromatin decondensation was induced with dithiothreitol; this showed that in the bulls with low fertility, more than 35 per cent of nuclei were decondensed, and that one of them had the lowest percentage of normal nuclei (64.9 per cent) and stronger positive reactions to the acid aniline blue and toluidine blue stains than the other bulls.
Nishijima, Kazutoshi; Kitajima, Shuji; Koshimoto, Chihiro; Morimoto, Masatoshi; Watanabe, Teruo; Fan, Jianglin; Matsuda, Yukihisa
This study was conducted to investigate whether soy lecithin can be used as an alternative cryoprotectant to establish a procedure that does not require the use of egg yolk to cryopreserve rabbit strains. Semen from Japanese White rabbits was frozen with HEPES extender containing 20% egg yolk (EYH), 0.5% (Lec-0.5), 1.5% (Lec-1.5), 2.5% (Lec-2.5), or 3.5% (Lec-3.5; wt/vol) lecithin (type IV-S, ≥30%), and the motility of thawed sperm was analyzed. The sperm motility in the Lec-1.5 group was significantly higher than that in the Lec-2.5 and 3.5 groups and equivalent to the EYH group. From 17 rounds of artificial insemination with frozen-thawed sperm in the EYH and Lec-1.5 groups, 12 rabbits in both groups were pregnant (70.6%) and delivered offspring. The litter size was 3.3 in the EYH group and 5.1 in the Lec-1.5 group. These results indicate that soy lecithin can be used as a substitute for egg yolk as a cryoprotectant on the basis of motility and fertility of the frozen-thawed rabbit sperm and that 1.5% lecithin (type IV-S, ≥30%) in the semen extender was the optimum concentration for rabbit sperm cryopreservation.
Huang, Peng; Li, Wenshu; Yang, Zhifang; Zhang, Ning; Xu, Yixin; Bao, Jianying; Jiang, Deke; Dong, Xianping
Lysozyme-like proteins (LYZLs) belong to the c-type lysozyme/α-lactalbumin family and are selectively expressed in the mammalian male reproductive tract. Two members, human sperm lysozyme-like protein (SLLP) -1 and mouse LYZL4, have been reported to contribute to fertilization but show no bacteriolytic activity. Here, we focused on the possible contribution of LYZL6 to immunity and fertilization. In humans, LYZL6 was selectively expressed by the testis and epididymis and became concentrated on spermatozoa. Native LYZL6 isolated from sperm extracts exhibited bacteriolytic activity against Micrococcus lysodeikticus. Recombinant LYZL6 (rLYZL6) reached its peak activity at pH 5.6 and 15 mM of Na+, and could inhibit the growth of Gram-positive, but not Gram-negative bacteria. Nevertheless, the bacteriolytic activity of rLYZL6 proved to be much lower than that of human lysozyme under physiological conditions. Immunodetection with a specific antiserum localized the LYZL6 protein on the postacrosomal membrane of mature spermatozoa. Immunoneutralization of LYZL6 significantly decreased the numbers of human spermatozoa fused with zona-free hamster eggs in a dose-dependent manner in vitro. Thus, we report here for the first time that LYZL6, an acidic, bacteriolytic and human sperm-related protein, is likely important for fertilization but not for the innate immunity of the male reproductive tract. PMID:28182716
Yuan, Shuiqiao; Schuster, Andrew; Tang, Chong; Yu, Tian; Ortogero, Nicole; Bao, Jianqiang; Zheng, Huili; Yan, Wei
Although it is believed that mammalian sperm carry small noncoding RNAs (sncRNAs) into oocytes during fertilization, it remains unknown whether these sperm-borne sncRNAs truly have any function during fertilization and preimplantation embryonic development. Germline-specific Dicer and Drosha conditional knockout (cKO) mice produce gametes (i.e. sperm and oocytes) partially deficient in miRNAs and/or endo-siRNAs, thus providing a unique opportunity for testing whether normal sperm (paternal) or oocyte (maternal) miRNA and endo-siRNA contents are required for fertilization and preimplantation development. Using the outcome of intracytoplasmic sperm injection (ICSI) as a readout, we found that sperm with altered miRNA and endo-siRNA profiles could fertilize wild-type (WT) eggs, but embryos derived from these partially sncRNA-deficient sperm displayed a significant reduction in developmental potential, which could be rescued by injecting WT sperm-derived total or small RNAs into ICSI embryos. Disrupted maternal transcript turnover and failure in early zygotic gene activation appeared to associate with the aberrant miRNA profiles in Dicer and Drosha cKO spermatozoa. Overall, our data support a crucial function of paternal miRNAs and/or endo-siRNAs in the control of the transcriptomic homeostasis in fertilized eggs, zygotes and two-cell embryos. Given that supplementation of sperm RNAs enhances both the developmental potential of preimplantation embryos and the live birth rate, it might represent a novel means to improve the success rate of assisted reproductive technologies in fertility clinics. PMID:26718009
Kawano, Natsuko; Yoshida, Kaoru; Miyado, Kenji; Yoshida, Manabu
Cell membranes are composed of many different lipids and protein receptors, which are important for regulating intracellular functions and cell signaling. To orchestrate these activities, the cell membrane is compartmentalized into microdomains that are stably or transiently formed. These compartments are called “lipid rafts”. In gamete cells that lack gene transcription, distribution of lipids and proteins on these lipid rafts is focused during changes in their structure and functions such as starting flagella movement and membrane fusion. In this paper, we describe the role of lipid rafts in gamete maturation, fertilization, and early embryogenesis. PMID:21490798
Park, C K; Hwang, I S; Cheong, H T; Yang, B K; Kim, C I
This study has evaluated the effect of fertilization-promoting peptide (FPP) on the fertilizing ability and glycosidase activity in vitro of frozen-thawed boar spermatozoa. Use of chlortetracycline (CTC) fluorescence analysis, as well as various glycosidase analyses and the oocyte penetration test showed that FPP can promote the fertilizing ability and glycosidase activity of frozen-thawed spermatozoa in vitro. There were significantly (P < 0.05) more acrosome-reacted and penetrated in medium with 100 nM FPP than with 0, 50, 200 or 400 nM. The beta-N-acetylglucosaminidase (beta-GlcNAcase) activity was at least two-fold higher than other glycosidase regardless of FPP concentrations. In the same glycosidase, there were no differences in medium with different concentrations of FPP. The percentages of spermatozoa that reached acrosome reaction were affected by different periods (0, 1, 2, 3 or 4 h) of spermatozoa preincubation and were higher in medium with than without FPP. Penetration rates were decreased with preincubation periods of spermatozoa when oocytes were inseminated with spermatozoa preincubated in medium with and without FPP for the different periods. These rates were higher in spermatozoa preincubated with that than without FPP and had a tendency to increase as time of culture periods when the sperm-oocyte were cultured for 4, 8, 12, 16, 20 or 24 h. The activities of alpha-fucosidase, alpha-mannosidase, beta-galactosidase and beta-GlcNAcase were higher in medium with that than without FPP regardless of periods of sperm preincubation and sperm-oocyte culture. These results suggest that FPP may have a positive role in promoting sperm function and glycosidase activity in the pig.
Daigneault, B W; McNamara, K A; Purdy, P H; Krisher, R L; Knox, R V; Rodriguez-Zas, S L; Miller, D J
Due to reduced fertility, cryopreserved semen is seldom used for commercial porcine artificial insemination (AI). Predicting the fertility of individual frozen ejaculates for selection of higher quality semen prior to AI would increase overall success. Our objective was to test novel and traditional laboratory analyses to identify characteristics of cryopreserved spermatozoa that are related to boar fertility. Traditional post-thaw analyses of motility, viability, and acrosome integrity were performed on each ejaculate. In vitro fertilization, cleavage, and blastocyst development were also determined. Finally, spermatozoa-oviduct binding and competitive zona-binding assays were applied to assess sperm adhesion to these two matrices. Fertility of the same ejaculates subjected to laboratory assays was determined for each boar by multi-sire AI and defined as (i) the mean percentage of the litter sired and (ii) the mean number of piglets sired in each litter. Means of each laboratory evaluation were calculated for each boar and those values were applied to multiple linear regression analyses to determine which sperm traits could collectively estimate fertility in the simplest model. The regression model to predict the percent of litter sired by each boar was highly effective (p < 0.001, r(2) = 0.87) and included five traits; acrosome-compromised spermatozoa, percent live spermatozoa (0 and 60 min post-thaw), percent total motility, and the number of zona-bound spermatozoa. A second model to predict the number of piglets sired by boar was also effective (p < 0.05, r(2) = 0.57). These models indicate that the fertility of cryopreserved boar spermatozoa can be predicted effectively by including traditional and novel laboratory assays that consider functions of spermatozoa.
Attia, S; Katila, T; Andersson, M
Good-quality semen is a prerequisite for successful and profitable artificial insemination (AI) of modern dairy cattle. Fertility of the bulls is evaluated with andrological examinations and semen analyses, such as morphology. However, little attention has been paid to the inheritance of bull fertility. In this study, we correlated sperm morphology, birth year and station of 695 AI bulls with calving rate (CR). Sperm morphology was clearly associated with CR underlining the usefulness of morphological examination in the assessment of fertility. The correlation between the proportion of normal spermatozoa and CR was significant (p < 0.001). No significant differences were detected between stations or birth years. We also compared the CR of 695 AI bulls with the CR of their 27 sires to study the inheritance of fertility. Sire's CR did not correlate with the CR of the sons (p = 0.218). This result indicates that at least when sires of acceptable CR are used to produce sons for use in AI the inheritance of CR is not significantly correlated.
Águila, L; Arias, M E; Vargas, T; Zambrano, F; Felmer, R
Mammalian sperm undergo a series of biochemical transformations in the female reproductive tract that are collectively known as capacitation. Cyclodextrins added to the sperm culture medium have been described to induce in vitro sperm capacitation, enabling its use in protein-free media. However, the additive capacitating effect of methyl-β-cyclodextrin (MβCD) in the medium containing bovine serum albumin (BSA) is unknown in the bovine species. In this study, we evaluated the effects of incubating frozen-thawed bovine spermatozoa in a BSA-containing medium supplemented with MβCD on different sperm quality and functional parameters. Sperm viability decreased with the addition of MβCD in a dose-dependent manner (p < 0.05), and DNA damage could be observed but only with the highest concentration of MβCD. However, pre-incubation of spermatozoa in MβCD-supplemented medium improved the capacitation status as assessed by the increase in plasma membrane fluidity, intracellular calcium concentration, induced acrosome reactivity and zona pellucida (ZP)-binding ability (p < 0.05). Thus, we conclude that MβCD supplementation is able to enhance the capacitation status of frozen-thawed bovine spermatozoa cultured in capacitation medium containing BSA and could result in a valid strategy for its application on artificial reproductive technologies such as in vitro fertilization or intracytoplasmic sperm injection.
Dorado, Jesús; Cid, Rosa Morales; Molina, Antonio; Hidalgo, Manuel; Ariza, Julia; Moreno-Millán, Miguel; Demyda-Peyrás, Sebastián
The present study investigated the effect of inbreeding depression on sperm quality using automated and objective methods and subsequent effects on beef bull field fertility. Individual inbreeding coefficient (F) values and field fertility data were determined using a dataset of AI bulls belonging to the Spanish Retinta Breeders Association (Asociación Nacional de Criadores de Ganado Vacuno Selecto de Raza Retinta (ANCRE)). Animals were clustered in two groups according to the F values as follows: (1) a high inbreeding group (HI; F ≥ 13.5%, mean 16.3); and (2) a non-inbreeding group (NI; F = 0%). In total, 17 different assessments were performed in both experimental groups, including evaluation of sperm morphology, acrosomal and DNA status, sperm plasma membrane integrity and function (hypo-osmotic swelling test), 10 kinetic parameters and the structure of sperm subpopulations. Sperm morphology, acrosomal and DNA status and osmotic tolerance were similar in both groups. Three velocity parameters (curvilinear velocity, straight line velocity and average path velocity) and the amplitude of lateral head displacement were higher in HI (P < 0.05). Cluster analysis of kinematic parameters revealed three different sperm subpopulations (sP1, sP2 and sP3), with the proportion of the sP1 population (highly active but non-progressive spermatozoa) being significantly (P < 0.05) higher in the HI group. Field fertility was assessed using two calving record datasets. In a smaller database including only bulls evaluated in the present study, there was a significant increase in the calving interval of cows sired with HI bulls. Conversely, in an extended genetic analysis of the ANCRE database, inbreeding only explained a small part of the variation in calving interval, and the results of regression analysis were not significant among bulls. The findings of the present study suggest that high inbreeding levels have a moderate effect on bull semen quality, with an increased
Kong, Nana; Xu, Xiaoting; Zhang, Yu; Wang, Yakun; Hao, Xiaoqiong; Zhao, Yu; Qiao, Jie; Xia, Guoliang; Zhang, Meijia
Mammalian spermatozoa undergo selective movement along the isthmus of the oviduct to the ampulla during ovulation, which is a prerequisite for fertilization. The factor(s) that involves in selective spermatozoa movement is still unknown. In this study, we found that the oviductal epithelium in mouse ampulla expressed high levels of natriuretic peptide type C (NPPC) in the presence of ovulated oocyte-cumulus complexes (OCCs). Spermatozoa expressed NPPC receptor natriuretic peptide receptor 2 (NPR2, a guanylyl cyclase) on the midpiece of flagellum. NPPC increased intracellular levels of cGMP and Ca2+ of spermatozoa, and induced sperm accumulation in the capillary by attraction. Importantly, spermatozoa from Npr2 mutant mice were not attracted by NPPC, preventing fertilization in vivo. Oocyte-derived paracrine factors promoted the expression of Nppc mRNA in the ampulla. Therefore, NPPC secreted by oviductal ampulla attracts spermatozoa towards oocytes, which is essential for fertilization. PMID:28054671
Wang, Meijiao; Yu, Tinghe; Hu, Lina; Cheng, Zhi; Li, Min
Ubiquitin C-terminal hydrolase L3 (UCHL3) belongs to the group of deubiquitinating enzymes and plays a part in apoptosis of germ cells and the differentiation of spermatocytes into spermatids. However, the exact role of UCHL3 in human spermatogenesis and sperm function remains unknown. Here we examined the level and activity of UCHL3 in spermatozoa from men with asthenozoospermia (A), oligoasthenozoospermia (OA) or normozoospermia (N). Immunofluorescence indicated that UCHL3 was mainly localized in the acrosome and throughout the flagella, and western blotting revealed a lower level in A or OA compared with N (p < 0.05). The catalytic activity of UCHL3 was decreased in spermatozoa from A or OA (p < 0.05, p < 0.001, respectively). The level and activity of UCHL3 were positively correlated with sperm count, concentration and motility. The UCHL3 level was positively correlated with the normal fertilization rate (FR) and percentage of embryos suitable for transfer/cryopreservation of in vitro fertilization (IVF). The UCHL3 activity was also positively correlated with FR, the percentage of embryos suitable for transfer/cryopreservation and high-quality embryos rate of IVF. Aforementioned correlations were not manifested in intra-cytoplasmic sperm injection (ICSI). These findings suggest that UCHL3 may play a role in male infertility. PMID:27780264
Shalizar Jalali, Ali; Najafi, Gholamreza; Hosseinchi, Mohammadreza; Sedighnia, Ashkan
Background: Stanozolol (ST) is a synthetic anabolic-androgenic steroid often abused by athletes. An increasing body of evidence points towards the role of ST misuses in the pathogenesis of a wide range of adverse effects including reprotoxicity. Objective: The aim of this study was to analyze the possible reproprotective effect of royal jelly (RJ) as an efficient antioxidant in ST-treated mice. Materials and Methods: Adult male mice were divided into four groups (n=5). Two groups of mice received ST (4.6 mg/kg/day) via gavage for 35 days. RJ was given orally to one of these groups at the dose level of 100 mg/kg body weight per day synchronously. Untreated control group and RJ-only treated group were also included. Epididymal sperm characteristics and in vitro fertilizing capacity were evaluated after 35 days. Results: ST treatment caused a significant (p<0.05) decrease in sperm count and motility and fertilization rate along with poor blastocyst formation and increased sperm DNA damage. Moreover, the incidence of apoptosis and abnormality in spermatozoa was significantly (p<0.05) higher in ST-exposed mice than those of control. The above-mentioned parameters were restored to near normal level by RJ co-administration. Conclusion: Data from the current study suggest that RJ has a potential repro-protective action against ST-induced reproductive toxicity in mice. However, clinical studies are warranted to investigate such an effect in human subjects. PMID:25653671
Takayama-Watanabe, Eriko; Campanella, Chiara; Kubo, Hideo; Watanabe, Akihiko
The egg jelly of Discoglossus pictus contains sperm motility-activating activity, the molecular basis of which has not been studied. Discoglossus pictus sperm initiated motility immediately after immersion in egg-jelly extract, as well as after immersion in hyposmotic solution, which initiates sperm motility in the external fertilization of anuran amphibians. Sequential treatment of the D. pictus sperm with these two solutions revealed the predominant effect of hyposmolality in initiation of motility. The motility initiation induced by jelly extract was suppressed by a monoclonal antibody (mAb) that is specific for the 34 kDa sperm motility-initiating substance (SMIS) in the egg jelly of the newt, Cynops pyrrhogaster. Immunoblotting using the anti-SMIS mAb revealed several antigenic proteins that included major ones with sizes of 18- and 34-kDa in D. pictus jelly extract. Scanning electron microscopic observation revealed that granules of jelly matrix, in which SMIS localizes and which have a critical role in the internal fertilization of C. pyrrhogaster, were not observed near the surface of the D. pictus egg jelly. These results suggest that sperm motility-activating activity in egg jelly of D. pictus may be mediated by SMIS homologous proteins that act through a mechanism that is partially different from that of C. pyrrhogaster.
Yokoe, Misato; Takayama-Watanabe, Eriko; Saito, Yoko; Kutsuzawa, Megumi; Fujita, Kosuke; Ochi, Haruki; Nakauchi, Yuni; Watanabe, Akihiko
Internal fertilization ensures successful reproduction of tetrapod vertebrates on land, although how this mode of reproduction evolved is unknown. Here, we identified a novel gene encoding sperm motility-initiating substance (SMIS), a key protein for the internal fertilization of the urodele Cynops pyrrhogaster by Edman degradation of an isolated protein and subsequent reverse transcription polymerase chain reaction. The SMIS gene encoded a 150 amino-acid sequence including the cysteine knot (CK) motif. No gene with substantial similarity to the SMIS was in the data bank of any model organisms. An active site of the SMIS was in the C-terminal region of the 2nd loop of CK motif. A synthetic peptide including the active site sequence bound to the midpiece and initiated/enhanced the circular motion of C. pyrrhogaster sperm, which allows penetration of the egg jelly specialized for the internal fertilization of this species. The synthetic peptide bound to whole sperm of Rhacophorus arboreus and enhanced the rotary motion, which is adapted to propel the sperm through egg coat matrix specialized for arboreal reproduction, while it bound to the tip of head and tail of Bufo japonicus sperm, and enhanced the vibratory motion, which is suited to sperm penetration through the egg jelly specialized for the reproduction of that species in freshwater. The polyclonal antibody against the active site of the SMIS specifically bound to egg coat matrix of R. arboreus. These findings suggest that diversification of amphibian reproductive modes accompanies the specialization of egg coat and the adaptation of sperm motility to penetrate the specialized egg coat, and SMIS acts as the sperm motility enhancer of anurans and urodeles that might facilitate to adaptively optimize sperm motility for allowing the establishment of internal fertilization.
Yokoe, Misato; Takayama-Watanabe, Eriko; Saito, Yoko; Kutsuzawa, Megumi; Fujita, Kosuke; Ochi, Haruki; Nakauchi, Yuni; Watanabe, Akihiko
Internal fertilization ensures successful reproduction of tetrapod vertebrates on land, although how this mode of reproduction evolved is unknown. Here, we identified a novel gene encoding sperm motility-initiating substance (SMIS), a key protein for the internal fertilization of the urodele Cynops pyrrhogaster by Edman degradation of an isolated protein and subsequent reverse transcription polymerase chain reaction. The SMIS gene encoded a 150 amino-acid sequence including the cysteine knot (CK) motif. No gene with substantial similarity to the SMIS was in the data bank of any model organisms. An active site of the SMIS was in the C-terminal region of the 2nd loop of CK motif. A synthetic peptide including the active site sequence bound to the midpiece and initiated/enhanced the circular motion of C. pyrrhogaster sperm, which allows penetration of the egg jelly specialized for the internal fertilization of this species. The synthetic peptide bound to whole sperm of Rhacophorus arboreus and enhanced the rotary motion, which is adapted to propel the sperm through egg coat matrix specialized for arboreal reproduction, while it bound to the tip of head and tail of Bufo japonicus sperm, and enhanced the vibratory motion, which is suited to sperm penetration through the egg jelly specialized for the reproduction of that species in freshwater. The polyclonal antibody against the active site of the SMIS specifically bound to egg coat matrix of R. arboreus. These findings suggest that diversification of amphibian reproductive modes accompanies the specialization of egg coat and the adaptation of sperm motility to penetrate the specialized egg coat, and SMIS acts as the sperm motility enhancer of anurans and urodeles that might facilitate to adaptively optimize sperm motility for allowing the establishment of internal fertilization. PMID:27579691
Costa, F; Barbisan, F; Assmann, C E; Araújo, N K F; de Oliveira, A R; Signori, J P; Rogalski, F; Bonadiman, B; Fernandes, M S; da Cruz, I B M
Previous investigations suggested that elevated cell-free DNA (cfDNA) can indicate non-healthy states. However, the potential association between cfDNA seminal plasma levels and fertility sperm parameters has not yet been determined. Therefore, the present study evaluated the association between seminal cfDNA levels and sperm fertility criteria to determine the use of seminal cfDNA quantification. An in vivo protocol quantified cfDNA levels of semen samples obtained from 163 male patients using fluorescent PicoGreen dye staining. To confirm if semen cfDNA quantification is realistic, an in vitro complementary test was performed using three or four semen samples. The fresh sperm samples were exposed to paraquat that generates high levels of superoxide anion causing oxidative stress and cell mortality. The results showed significant association between dsDNA levels and several sperm fertility parameters, such as low viability and alterations of motility and morphology. The in vitro analysis confirmed the association between dsDNA levels and sperm viability. Together, these results suggest that dsDNA levels could be an important biomarker to test sperm fertility.
Watanabe, Akihiko; Takayama-Watanabe, Eriko
A specific sperm-egg interaction in the oviductal matrix is crucial for internal fertilization of the red-bellied newt, Cynops pyrrhogaster. An understanding of the molecular basis of this interaction is expected to elucidate the evolutionary history of internal fertilization in amphibians. Recently, deep sequencing technology has provided global gene information even in nonmodel animals, allowing us to understand specific features of the molecular mechanisms underlying fertilization in C. pyrrhogaster. In the present study, we screened de novo assembled RNAseq from ovary, testis, and oviduct samples in C. pyrrhogaster and identified the base sequences encoding zona pellucida (ZP) proteins, voltage-dependent Ca(2+) channels, and cysteine-rich secretory proteins (CRISPs), which respectively are sperm receptors for egg envelopes, major mediators of sperm intracellular signaling, and expected extracellular modulators for sperm function in the female reproductive tract. In the ovary, ZP homologues of all six subgroups were found, including a ZP1 homologue that was newly found in amphibians, a ZP4 homologue, and six ZPC homologues. The unique combination of ZP proteins suggests a new mechanism for sperm binding to egg envelopes in the internal fertilization of C. pyrrhogaster. In the testis, CaV1.1, 1.2, and 3.2, which are L- and T-type voltage-dependent Ca(2+) channels, were found as potential mediators for the internal fertilization-specific sperm-egg interaction. We also found CRISP 2 in the oviduct, which is speculated to participate in the sperm-egg interaction. These results indicate that the de novo assembled RNAseq is a powerful tool allowing analysis of the specific sperm-egg interactions in C. pyrrhogaster.
De Lisa, Emilia; Salzano, Anna Maria; Moccia, Francesco; Scaloni, Andrea; Di Cosmo, Anna
Marine invertebrates exhibit both chemokinesis and chemotaxis phenomena, induced in most cases by the release of water-borne peptides or pheromones. In mollusks, several peptides released during egg-laying improve both male attraction and mating. Unlike other cephalopods, Octopus vulgaris adopts an indirect internal fertilization strategy. We here report on the identification and characterization of a chemoattractant peptide isolated from mature eggs of octopus females. Using two-chamber and time-lapse microscopy assays, we demonstrate that this bioactive peptide is able to increase sperm motility and induce chemotaxis by changing the octopus spermatozoa swimming behavior in a dose-dependent manner. We also provide evidence that chemotaxis in the octopus requires the presence of extracellular calcium and membrane protein phophorylation at tyrosine. This study is the first report on a sperm-activating factor in a non-free-spawning marine animal.
Shahzad, Qaisar; Mehmood, Muhammad Usman; Khan, Hamayun; ul Husna, Asma; Qadeer, Saima; Azam, Asima; Naseer, Zahid; Ahmad, Ejaz; Safdar, Muhammad; Ahmad, Mushtaq
Two experiments were conducted to evaluate the effect of royal jelly (RJ) on post-thaw sperm quality, in vitro and in vivo fertility rate of cryopreserved buffalo bull sperm. The semen was collected from three mature regular donor buffalo bulls, ejaculates were pooled and semen evaluated initially. In Experiment 1, the ejaculates were extended in tris-citric acid diluter supplemented with different RJ concentrations (0, 0.05, 0.1, 0.2, 0.3 or 0.4%). The diluted semen was cooled to 4°C, packaged into 0.5 mL straws and frozen using standard procedure. The straws were thawed and assessed for sperm progressive motility, viability, plasma membrane, acrosome, and chromatin integrity. The results indicated that sperm progressive motility was significantly greater (P<0.05) in 0.05, 0.1, 0.2 and 0.3% RJ than 0.4% RJ supplemented and control groups. The sperm viability, plasma membrane and acrosome integrity were significantly improved (P<0.05) in 0.1% RJ supplemented group the compared to other treatment groups. In Experiment 2, cryopreserved sperm with 0.1% RJ supplementation and control (without RJ supplementation) were used to observe the in vitro fertilizing potential and in vivo fertility. In vitro fertilization method was applied to assess the cleavage rate; whereas, AI was performed in buffalo during in vivo fertility trial. The buffaloes were inseminated 12h after standing estrus and pregnancy diagnosis was performed through ultrasonography. The results revealed that the cleavage rate was higher (P<0.05) in 0.1% RJ as compared to control group. However, the pregnancy rate was similar (P>0.05) between 0.1% RJ supplemented and control groups. It is concluded that supplementation of RJ in freezing extender can improve the cryosurvival rate and in vitro fertilizing capacity of buffalo bull sperm.
Poverini, Roberta; Lisi, Rosella; Carra, Maria Cristina; Lisi, Franco
Motility is the feature that allows spermatozoa to actively reach and penetrate the female gamete during fertilization. When this function is altered, and especially decreased, troubles in conceiving may occur. In this study, we demonstrated that treating fertile women with myo-inositol (MI) vaginal suppositories ameliorated their partners' sperm motility and also positively affected their conceiving capacity, without changes in cervical mucus structural and biochemical characteristics. Indeed, by means of the postcoital test on female cervical mucus, a significant improvement especially in progressive sperm motility was recorded after MI suppository use. Concomitantly, after MI treatment, a reduction of immotile spermatozoa percentage was observed. Importantly, MI vaginal supplementation positively correlated with a pregnancy for 5 of the 50 couples enrolled in the study, leading us to speculate that this substance may substantially contribute to create in the cervical mucus an ideal milieu that makes spermatozoa more motile and functionally able to fertilize. Even though the detailed mechanism is still unclear, these results should encourage MI vaginal use for the clinical improvement of male infertility, through their partners. PMID:27403162
Montanino Oliva, Mario; Poverini, Roberta; Lisi, Rosella; Carra, Maria Cristina; Lisi, Franco
Motility is the feature that allows spermatozoa to actively reach and penetrate the female gamete during fertilization. When this function is altered, and especially decreased, troubles in conceiving may occur. In this study, we demonstrated that treating fertile women with myo-inositol (MI) vaginal suppositories ameliorated their partners' sperm motility and also positively affected their conceiving capacity, without changes in cervical mucus structural and biochemical characteristics. Indeed, by means of the postcoital test on female cervical mucus, a significant improvement especially in progressive sperm motility was recorded after MI suppository use. Concomitantly, after MI treatment, a reduction of immotile spermatozoa percentage was observed. Importantly, MI vaginal supplementation positively correlated with a pregnancy for 5 of the 50 couples enrolled in the study, leading us to speculate that this substance may substantially contribute to create in the cervical mucus an ideal milieu that makes spermatozoa more motile and functionally able to fertilize. Even though the detailed mechanism is still unclear, these results should encourage MI vaginal use for the clinical improvement of male infertility, through their partners.
Alvarez-Gallardo, Horacio; Kjelland, Michael E.; Moreno, Juan F.; Welsh, Thomas H.; Randel, Ronald D.; Lammoglia, Miguel A.; Pérez-Martínez, Mario; Lara-Sagahón, Alma V.; Esperón-Sumano, A. Enrique; Romo, Salvador
A decrease in fertility can have a negative economic impact, both locally and over a broader geographical scope, and this is especially the case with regard to the cattle industry. Therefore, much interest exists in evaluating proteins that might be able to increase the fertility of sperm. Heparin binding proteins (HBPs), specifically the fertility associated antigen (FAA) and the Type-2 tissue inhibitor of metalloproteinase (TIMP-2), act to favor the capacitation and acrosome reaction and perhaps even modulate the immune system’s response toward the sperm. The objective of this research was to determine the effect on fertility of adding recombinant FAA (rFAA) and recombinant TIMP-2 (rTIMP-2) to bovine semen before cryopreservation for use in an artificial insemination (AI) program in a tropical environment. For this experiment, 100 crossbred (Bos taurus x Bos indicus) heifers were selected based on their estrus cycle, body condition score (BCS), of 4 to 6 on a scale of 1 to 9, and adequate anatomical conformation evaluated by pelvic and genital (normal) measurements. Heifers were synchronized using estradiol benzoate (EB), Celosil® (PGF2α) (Shering-Plough) and a controlled internal drug release (CIDR) device was inserted that contained progesterone. Inseminations were performed in two groups at random, 50 animals per group. The control group was inseminated with conventional semen. The treatment group was inseminated with semen containing rFAA (25 µg/mL) and rTIMP-2 (25 µg/mL). In the control group a 16% pregnancy rate was obtained versus a 40% pregnancy rate for the HBP treatment group, resulting in a significant difference (P = 0.0037). Given the results herein, one may conclude that the HBPs can increase fertility and could be an option for cattle in tropical conditions; however, one needs to consider the environment, nutrition, and the genetic interaction affecting the final result in whatever reproductive program that is implemented. PMID:23762288
We have previously defined distinct localizations of antigens on the surface of the guinea pig sperm using monoclonal antibodies. In the present study we have demonstrated that these antigen localizations are dynamic and can be altered during changes in the functional state of the sperm. Before the sperm is capable of fertilizing the egg, it must undergo capacitation and an exocytic event, the acrosome reaction. Prior to capacitation, the antigen recognized by the monoclonal antibody, PT-1, was restricted to the posterior tail region (principle piece and end piece). After incubation in capacitating media at 37 degrees C for 1 h, 100% of the sperm population showed migration of the PT-1 antigen onto the anterior tail. This redistribution of surface antigen resulted from a migration of the surface molecules originally present on the posterior tail. It did not occur in the presence of metabolic poisons or when tail-beating was prevented. It was temperature-dependent, and did not require exogenous Ca2+. Since the PT- 1 antigen is freely diffusing on the posterior tail before migration, the mechanism of redistribution could involve the alteration of a presumptive membrane barrier. In addition, we observed the redistribution of a second surface antigen after the acrosome reaction. The antigen recognized by the monoclonal antibody, PH-20, was localized exclusively in the posterior head region of acrosome-intact sperm. Within 7-10 min of induction of the acrosome reaction with Ca2+ and A23187, 90-100% of the acrosome-reacted sperm population no longer demonstrated binding of the PH-20 antibody on the posterior head, but showed binding instead on the inner acrosomal membrane. This redistribution of the PH-20 antigen also resulted from the migration of pre-existing surface molecules, but did not appear to require energy. The migration of PH-20 antigen was a selective process; other antigens localized to the posterior head region did not leave the posterior head after the
Ru, Yan-Fei; Xue, Hai-Min; Ni, Zi-Mei; Xia, Dong; Zhou, Yu-Chuan; Zhang, Yong-Lian
Despite the fact that the phenomenon of capacitation was discovered over half century ago and much progress has been made in identifying sperm events involved in capacitation, few specific molecules of epididymal origin have been identified as being directly involved in this process in vivo. Previously, our group cloned and characterized a carboxyl esterase gene Ces5a in the rat epididymis. The CES5A protein is mainly expressed in the corpus and cauda epididymidis and secreted into the corresponding lumens. Here, we report the function of CES5A in sperm maturation. By local injection of Lentivirus-mediated siRNA in the CES5A-expressing region of the rat epididymis, Ces5a-knockdown animal models were created. These animals exhibited an inhibited sperm capacitation and a reduction in male fertility. These results suggest that CES5A plays an important role in sperm maturation and male fertility. PMID:25475668
Lumley, Alyson J; Diamond, Sian E; Einum, Sigurd; Yeates, Sarah E; Peruffo, Danielle; Emerson, Brent C; Gage, Matthew J G
There is increasing evidence that females can somehow improve their offspring fitness by mating with multiple males, but we understand little about the exact stage(s) at which such benefits are gained. Here, we measure whether offspring fitness is influenced by mechanisms operating solely between sperm and egg. Using externally fertilizing and polyandrous Atlantic salmon (Salmo salar), we employed split-clutch and split-ejaculate in vitro fertilization experiments to generate offspring using designs that either denied or applied opportunities for sperm competition and cryptic female choice. Following fertilizations, we measured 140 days of offspring fitness after hatch, through growth and survival in hatchery and near-natural conditions. Despite an average composite mortality of 61%, offspring fitness at every life stage was near-identical between groups fertilized under the absence versus presence of opportunities for sperm competition and cryptic female choice. Of the 21 551 and 21 771 eggs from 24 females fertilized under monandrous versus polyandrous conditions, 68% versus 67.8% survived to the 100-day juvenile stage; sub-samples showed similar hatching success (73.1% versus 74.3%), had similar survival over 40 days in near-natural streams (57.3% versus 56.2%) and grew at similar rates throughout. We therefore found no evidence that gamete-specific interactions allow offspring fitness benefits when polyandrous fertilization conditions provide opportunities for sperm competition and cryptic female choice.
Lumley, Alyson J.; Diamond, Sian E.; Einum, Sigurd; Yeates, Sarah E.; Peruffo, Danielle; Emerson, Brent C.; Gage, Matthew J. G.
There is increasing evidence that females can somehow improve their offspring fitness by mating with multiple males, but we understand little about the exact stage(s) at which such benefits are gained. Here, we measure whether offspring fitness is influenced by mechanisms operating solely between sperm and egg. Using externally fertilizing and polyandrous Atlantic salmon (Salmo salar), we employed split-clutch and split-ejaculate in vitro fertilization experiments to generate offspring using designs that either denied or applied opportunities for sperm competition and cryptic female choice. Following fertilizations, we measured 140 days of offspring fitness after hatch, through growth and survival in hatchery and near-natural conditions. Despite an average composite mortality of 61%, offspring fitness at every life stage was near-identical between groups fertilized under the absence versus presence of opportunities for sperm competition and cryptic female choice. Of the 21 551 and 21 771 eggs from 24 females fertilized under monandrous versus polyandrous conditions, 68% versus 67.8% survived to the 100-day juvenile stage; sub-samples showed similar hatching success (73.1% versus 74.3%), had similar survival over 40 days in near-natural streams (57.3% versus 56.2%) and grew at similar rates throughout. We therefore found no evidence that gamete-specific interactions allow offspring fitness benefits when polyandrous fertilization conditions provide opportunities for sperm competition and cryptic female choice. PMID:27069665
Sperm concentration and count are often used as indicators of environmental impacts on male reproductive health. Existing clinical databases may be biased towards sub-fertile men with low sperm counts and less is known about expected sperm count distributions in cohorts of ferti...
Liu, Y; Qu, F; Cao, X; Chen, G; Guo, Q; Ying, X; Guo, W; Lu, L; Ding, Z
Fertilization, the recognition and fusion between spermatozoa and oocyte, involves various molecules on the spermatozoa and oocyte membranes. Concanavalin A (ConA)-binding proteins may be one of the molecules involved in mammal spermatozoa fertilization; however, their structure and function remain largely unknown. Here, we initially identified a ConA-binding protein, Zn-α2-glycoprotein (ZAG), involved in regulating the acrosome reaction (AR) of human spermatozoa. ZAG is localized on the pre-equatorial region covering the acrosome, neck and tail (some parts of middle piece and principal piece respectively) regions of the acrosome intact human spermatozoa, and disappears in the acrosomal region of the acrosome-reacted spermatozoa. Polyclonal antibodies against human recombinant ZAG significantly reduced the AR and sperm capability binding to human zona pellucida or penetration into zona-free hamster oocytes. Furthermore, assessment of the signaling pathways regulated by ZAG revealed that ZAG affects sperm AR through both the cAMP/PKA and PKC pathways. These results indicate that ZAG, which is present on the human sperm membrane, plays a critical role in the AR and subsequently, may be involved in sperm fertility.
Guimarães, A C G; Leivas, F G; Santos, F W; Schwengber, E B; Giotto, A B; Machado, C I U; Gonçalves, C G M; Folchini, N P; Brum, D S
The objective of this study was to determine the effect of different centrifugation forces in bovine sperm separation by discontinuous Percoll gradients for in vitro fertilization IVF. The semen samples from each bull were pooled or each bull were centrifuged separately and centrifuged in discontinuous Percoll gradients (30, 60 and 90%) at different forces: F1 (9000×g), F2 (6500×g), F3 (4500×g) and F4 (2200×g), according experiment. The sperm samples were evaluated to determine the concentration, motility, vigor, morphology, reactive oxygen species (ROS), integrity of the plasma membrane, lipid peroxidation, antioxidants and embryo development were also evaluated. No difference was observed in the concentration of sperm submitted to different centrifugation forces. The total percentage of motile sperm was increased after centrifugation at F3 and F4, and the ROS production at F1 was greater than the other forces. When the bulls semen were processed individually, no significant differences were observed for the sperm quality parameters between F1 and F4, including lipid peroxidation, antioxidants, cleavage rate and average time to the first cleavage. This work demonstrated for the first time that centrifugation at 2200×g enhanced the sperm penetration and fertilization rates without reducing sperm recovery compared to the typical centrifugation force (9000×g) currently used by the commercial bovine IVF industry.
Nikseresht, Mohsen; Fallahzadeh, Ali Reza; Toori, Mehdi Akbartabar
Background Pomegranate has been taken great scientific attention in recent years due to its health benefits. Pomegranate seed oil is a rich source of 9-cis, and 11-trans conjugate linolenic acid. The aim of this study was to evaluate the effect of dietary pomegranate seed oil on the fertilization potency of rat’s sperm. Materials and Methods Twenty-four male Wistar rats were divided into four groups. The first group, which served as the control group, received 1 mL of corn oil for seven weeks. Groups II, III, IV served as the experimental groups received 200, 500 and 1000 mg/kg of pomegranate seed oil, for the same period of time respectively. After seven weeks, all of the rats were sacrificed, and their epididymis sperm was collected and added to IVF medium (T6) containing metaphase II oocytes. Almost 21 oocytes had been removed from every female rat oviduct. In this medium, oocyte fertilization, cleavage rates, and embryo development into blastocysts, were evaluated by inverted microscopy. Results Levels of LD50 in the oral route in male rats were more than 5000 mg/kg body weight. Our data showed that the rates of fertilization, cleavage and embryo development into blastocysts were higher in the groups that had received 500 and 1000 mg/kg body weight of pomegranate seed oil. Conclusion This study demonstrated that pomegranate seed oil had a positive effect on the fertilization potency of male rats. These beneficial effects may be useful in assisted reproductive technology. PMID:26816914
Pasch, Elisabeth; Link, Jana; Beck, Carolin; Scheuerle, Stefanie; Alsheimer, Manfred
ABSTRACT LINC complexes are evolutionarily conserved nuclear envelope bridges, physically connecting the nucleus to the peripheral cytoskeleton. They are pivotal for dynamic cellular and developmental processes, like nuclear migration, anchoring and positioning, meiotic chromosome movements and maintenance of cell polarity and nuclear shape. Active nuclear reshaping is a hallmark of mammalian sperm development and, by transducing cytoskeletal forces to the nuclear envelope, LINC complexes could be vital for sperm head formation as well. We here analyzed in detail the behavior and function of Sun4, a bona fide testis-specific LINC component. We demonstrate that Sun4 is solely expressed in spermatids and there localizes to the posterior nuclear envelope, likely interacting with Sun3/Nesprin1 LINC components. Our study revealed that Sun4 deficiency severely impacts the nucleocytoplasmic junction, leads to mislocalization of other LINC components and interferes with the formation of the microtubule manchette, which finally culminates in a globozoospermia-like phenotype. Together, our study provides direct evidence for a critical role of LINC complexes in mammalian sperm head formation and male fertility. PMID:26621829
Drosophila females engage in multiple matings     even though they can store sperm in specialized organs for most of their life . The existence of sperm competition in Drosophila has been inferred from the proportion of progeny sired by the second male in double-mating experiments   . Investigators have used this approach to quantify genetic variation underlying sperm competition   , to elucidate its genetic basis , to identify the dependence of different male competitive ability on the genotype of the females with which they mate  and to discern the potential role of sperm competition in species isolation  . This approach assumes that the sperm from two males stored in a female compete to fertilize the eggs. The mechanism by which sperm competition is accomplished is still unknown, however. Here, fluorescence microscopy, cytometry, and differently labeled sperm were used to analyze the fate of sperm inside the female's sperm storage organs, to quantify sperm competition, and to assess how closely paternity success corresponds to the appearance and location of the sperm. The results show that the first male's sperm is retained for a shortened period if the female remates, and that the second males that sire more progeny either induce females to store and use more of their sperm or strongly displace resident sperm.
Shi, Lin; Liu, Shan; Zhao, Wanqiu; Zhou, Hanying; Ren, Wenjuan; Shi, Juanzi
Whether hepatitis B virus (HBV) infection impairs human infertility is unclear. The present retrospective case-controlled study investigated the impact of HBV on sperm parameters, ovarian stimulation, and outcomes of in vitro fertilization (IVF) and embryo transfer. A total of 224 couples with at least one partner being HBsAg-seropositive undergoing their first IVF and embryo transfer cycle were identified, which included 77 couples with female partners being HBsAg-seropositive, 136 couples with male partners being HBsAg-seropositive, and 11 couples with both partners being HBsAg-seropositive. A total of 448 both HBsAg-seronegative couples served as controls. The percentage of normal sperm morphology was significantly lower in HBsAg-seropositive male partners than that in HBsAg-seronegative male partners (11.9 ± 9.4% vs. 19.0 ± 11.9%, P < 0.01). The duration of infertility was significantly prolonged in HBV-seropositive patients compared with HBV-seronegative patients (4.9 vs. 4.1 years, P < 0.01). Couples with female partners being HBsAg-seropositive had significantly lower top-quality embryo rate than control group (22.4% vs. 31.6%, P < 0.01). In addition, the fertilization rates in groups with male or female partners being HBsAg-seropositive were both significantly lower than the matched controls (80.2% vs. 82.8%, P < 0.05; 76.6% vs. 84.3%, P < 0.01, respectively). HBV infection was also found to be associated negatively with fertilization rate by logistic regression analysis (odds ratios: 0.410, 95% confidence interval: 0.186-0.906, P < 0.05). However, there was no significant difference in clinical pregnancy rates between HBsAg-seropositive and HBsAg-seronegative group. These results suggest that chronic HBV infection is likely to represent a significant cause of infertility.
Hilário, Ana; Young, Craig M; Tyler, Paul A
Vestimentiferan tubeworms are ecologically important members of deep-sea chemosynthetic communities, including hydrothermal vents and cold seeps. Some are community dominants and others are primary colonists of new vent sites; they include some of the longest living and fastest growing marine invertebrates. Their mechanisms of propagation, dispersal, and genetic exchange have been widely discussed. Direct sperm transfer from males to females has been documented in one species, Ridgeia piscesae, but others are known to discharge what are apparently primary oocytes. Brooding of embryos has never been observed in any vestimentiferan. These observations have led to the supposition that fertilization might be external in most species. Here we report sperm storage at the posterior end of the oviduct in five species, including tubeworms from both vents and seeps. We show experimentally that most eggs are inseminated internally, that fertilization rate is typically lower than 100%, that meiosis is completed after eggs are released from the female, and that the dispersal phase includes the entire embryonic period.
Parrish, John J
As a result of research in the 1980s on in vitro maturation, sperm capacitation, and in vitro fertilization, the bovine is now one of the important models for development. Further, the current production of bovine embryos in vitro rivals that of in vivo embryo production for commercial applications. Researchers of today may be unaware of why decisions were made in the procedures. This review addresses the state of the art at the time of the work by Parrish et al. (Bovine in vitro fertilization with frozen thawed semen. Theriogenology 1986;25:591-600), and how later work would explain success or failure of competing procedures. Important was the use of frozen semen and heparin capacitation, because this allowed future researchers/practitioners to change sperm numbers and capacitation conditions to adjust for variations among bulls. The large numbers of citation of the original work stand the testament of time in the repeatability and success of the procedures. The work was done within the environment of the N.L. First laboratory and the unique interactions with a large number of talented graduate students, postdoctoral researchers, and technicians.
Borg, Michael; Rutley, Nicholas; Kagale, Sateesh; Hamamura, Yuki; Gherghinoiu, Mihai; Kumar, Sanjeev; Sari, Ugur; Esparza-Franco, Manuel A; Sakamoto, Wataru; Rozwadowski, Kevin; Higashiyama, Tetsuya; Twell, David
The production of the sperm cells in angiosperms requires coordination of cell division and cell differentiation. In Arabidopsis thaliana, the germline-specific MYB protein DUO1 integrates these processes, but the regulatory hierarchy in which DUO1 functions is unknown. Here, we identify an essential role for two germline-specific DUO1 target genes, DAZ1 and DAZ2, which encode EAR motif-containing C2H2-type zinc finger proteins. We show that DAZ1/DAZ2 are required for germ cell division and for the proper accumulation of mitotic cyclins. Importantly, DAZ1/DAZ2 are sufficient to promote G2- to M-phase transition and germ cell division in the absence of DUO1. DAZ1/DAZ2 are also required for DUO1-dependent cell differentiation and are essential for gamete fusion at fertilization. We demonstrate that the two EAR motifs in DAZ1/DAZ2 mediate their function in the male germline and are required for transcriptional repression and for physical interaction with the corepressor TOPLESS. Our findings uncover an essential module in a regulatory hierarchy that drives mitotic transition in male germ cells and implicates gene repression pathways in sperm cell formation and fertility.
Barranco, Isabel; Tvarijonaviciute, Asta; Perez-Patiño, Cristina; Parrilla, Inmaculada; Ceron, Jose J; Martinez, Emilio A; Rodriguez-Martinez, Heriberto; Roca, Jordi
The study attempted to clarify the role of total antioxidant capacity of seminal plasma (SP-TAC) on boar sperm survival and fertility after artificial insemination (AI). SP-TAC differed (P < 0.001) among boars (n° = 15) and, to a lesser degree, among ejaculates within male (4 ejaculates/boar). SP-TAC also differed (P < 0.001) among ejaculate fractions (43 ejaculates and 3 fractions per ejaculate), of which the sperm-peak portion of the sperm rich ejaculate fraction (SRF) had the highest SP-TAC. SP-TAC was not correlated with sperm quality (motility and viability) or functionality (intracellular ROS generation and lipid peroxidation) of liquid AI-semen samples stored at 17 °C for 72 h (90 AI-samples), but the decline in sperm quality was larger (P < 0.05) in ejaculates with low, compared with high SP-TAC (hierarchically grouped). The SP-TAC differences among ejaculate portions agree with sperm cryosurvival rates (14 ejaculates from 7 boars), showing sperm from sperm-peak portion better (P < 0.01) post-thaw quality and functionality than those from the entire ejaculate (mainly post-SRF). Boars (n° = 18) with high SP-TAC (hierarchically grouped) had higher (P < 0.05) fertility outcomes (5,546 AI-sows) than those with low SP-TAC. Measurement of SP-TAC ought to be a discriminative tool to prognosis fertility in breeding boars.
Barranco, Isabel; Tvarijonaviciute, Asta; Perez-Patiño, Cristina; Parrilla, Inmaculada; Ceron, Jose J.; Martinez, Emilio A.; Rodriguez-Martinez, Heriberto; Roca, Jordi
The study attempted to clarify the role of total antioxidant capacity of seminal plasma (SP-TAC) on boar sperm survival and fertility after artificial insemination (AI). SP-TAC differed (P < 0.001) among boars (n° = 15) and, to a lesser degree, among ejaculates within male (4 ejaculates/boar). SP-TAC also differed (P < 0.001) among ejaculate fractions (43 ejaculates and 3 fractions per ejaculate), of which the sperm-peak portion of the sperm rich ejaculate fraction (SRF) had the highest SP-TAC. SP-TAC was not correlated with sperm quality (motility and viability) or functionality (intracellular ROS generation and lipid peroxidation) of liquid AI-semen samples stored at 17 °C for 72 h (90 AI-samples), but the decline in sperm quality was larger (P < 0.05) in ejaculates with low, compared with high SP-TAC (hierarchically grouped). The SP-TAC differences among ejaculate portions agree with sperm cryosurvival rates (14 ejaculates from 7 boars), showing sperm from sperm-peak portion better (P < 0.01) post-thaw quality and functionality than those from the entire ejaculate (mainly post-SRF). Boars (n° = 18) with high SP-TAC (hierarchically grouped) had higher (P < 0.05) fertility outcomes (5,546 AI-sows) than those with low SP-TAC. Measurement of SP-TAC ought to be a discriminative tool to prognosis fertility in breeding boars. PMID:26688188
Beek, J; Nauwynck, H; Maes, D; Van Soom, A
In this study, we report for the first time on a possible contribution of metalloproteases in sperm passage through the cumulus matrix in pigs. The presence of 20 μM 1,10-phenanthroline (1,10-PHEN), inhibitor of zinc-dependent metalloproteases, strongly inhibited the degree of sperm penetration in cumulus-intact (CI), but not in cumulus-free (CF), porcine oocytes during IVF. The inhibitory effect of 1,10-PHEN was due to the chelation of metal ions as a non-chelating analog (1,7-PHEN) did not affect IVF rates. Furthermore, incubation with 1,10-PHEN did not affect sperm binding to the zona pellucida nor sperm motility, membrane integrity, or acrosomal status. These findings led to the assumption that 1,10-PHEN interacts with a sperm- or cumulus-derived metalloprotease. Metalloproteases are key players in physiological processes involving degradation or remodeling of extracellular matrix. In vivo, their proteolytic activity is regulated by tissue inhibitors of metalloproteases (TIMP1-TIMP4). We tested the effect of TIMP3 on fertilization parameters after porcine IVF. Similar to 1,10-PHEN, TIMP3 inhibited total fertilization rate of CI but not CF oocytes and did not influence sperm quality parameters. Although the inhibitory effect was stronger in CI oocytes, TIMP3 also reduced the degree of sperm penetration in CF oocytes, suggesting the involvement of a metalloprotease in a subsequent step during fertilization. In conclusion, our results indicate the involvement of TIMP3-sensitive, zinc-dependent metalloprotease activity in sperm passage through the cumulus oophorus in pigs. The results should provide the basis for further biochemical research toward the localization and identification of the metalloprotease involved.
Iwao, Yasuhiro; Shiga, Keiko; Shiroshita, Ayumi; Yoshikawa, Tomoyasu; Sakiie, Maho; Ueno, Tomoyo; Ueno, Shuichi; Ijiri, Takashi W; Sato, Ken-ichi
Monospermic fertilization in the frog, Xenopus laevis, is ensured by a fast-rising, positive fertilization potential to prevent polyspermy on the fertilized egg, followed by a slow block with the formation of a fertilization envelope over the egg surface. In this paper, we found that not only the enzymatic activity of sperm matrix metalloproteinase-2 (MMP-2) was necessary for a sperm to bind and/or pass through the extracellular coat of vitelline envelope, but also the hemopexin (HPX) domain of MMP-2 on the sperm surface was involved in binding and membrane fusion between the sperm and eggs. A peptide with a partial amino acid sequence of the HPX domain caused egg activation accompanied by an increase in [Ca(2+)]i in a voltage-dependent manner, similar to that in fertilization. The membrane microdomain (MD) of unfertilized eggs bound the HPX peptide, and this was inhibited by ganglioside GM1 distributed in the MD. The treatment of sperm with GM1 or anti-MMP-2 HPX antibody allows the sperm to fertilize an egg clamped at 0 mV, which untreated sperm cannot achieve. We propose a model accounting for the mechanism of voltage-dependent fertilization based on an interaction between the positively charged HPX domain in the sperm membrane and negatively-charged GM1 in the egg plasma membrane.
Anifandis, George; Messini, Christina; Dafopoulos, Konstantinos; Sotiriou, Sotiris; Messinis, Ioannis
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
Long, Julie A; Purdy, Phillip H; Zuidberg, Kees; Hiemstra, Sipke-Joost; Velleman, Sandra G; Woelders, Henri
Cryopreservation methods for poultry semen are not reliable for germplasm preservation, especially for turkeys, where fertility rates from frozen/thawed semen are particularly low. The objective was to evaluate cryopreservation methods for effectiveness in promoting cryosurvival and post-thaw function of sperm from five turkey lines: one commercial line and four research (RBC1; E; RBC2; F) lines from Ohio State University (OSU). The model for cryopreservation was set up as a 2×2×2×5 design for cryoprotectant (glycerol or dimethylacetamide (DMA)), cryopreservation medium (Lake or ASG), method of dilution (fixed dilution volume versus fixed sperm concentration) and turkey line, respectively. The final cryoprotectant concentrations were 11% glycerol or 6% DMA. Thawed sperm were evaluated for plasma membrane integrity and quality, motility, acrosome integrity and, after artificial insemination, for egg fertility and hatchability. Commercial turkey hens were used for all fertility trials, regardless of semen source. Turkey sperm frozen with glycerol exhibited higher membrane integrity and membrane quality upon thawing than turkey sperm frozen with DMA although no differences in total motility, and only minimal differences in progressive motility, were detected among the eight cryopreservation treatments. Within line, fertility was affected by cryoprotectant, medium and dilution method, where the overall highest percentages of fertile, viable embryos (Day 7) occurred for the DMA/ASG/fixed sperm concentration method, while high percentages (15.8-31.5%) of fertile, non-viable embryos (Day 1-6) were observed for multiple cryopreservation methods, including two glycerol treatments. From a single insemination, the duration of true and viable fertility in all lines was 10-13 weeks and 9-10 weeks, respectively. The duration of hatchability was 4-6 weeks after insemination for four of the turkey lines. The highest percentage of viable embryos was observed for the commercial
Li, Jingchun; Ning, Bolin; Cao, Xinyan; Luo, Yinghua; Guo, Li; Wei, Guosheng; Liu, Shengjun; Zhang, Ying; Zhang, Aizhong; Wu, Rui; Li, Yanbing
This study presents a novel method for the separation of motile sperm from non-progressive motile and immotile sperm and in vitro Fertilization (IVF). This separation of bull sperm was accomplished by inducing chemotaxis along a progesterone release agent in a 7.5-mm microchannel microchip composed of a biocompatible polydimethysiloxane layer and a glass gradient. The selected sperm was applied directly for IVF. In the first experiment, we tested the effect of different lengths of microchannnel (5mm, 7.5mm and 10mm) on quality parameter of separated sperm. The results showed that separated sperm using 7.5-mm microchannel chip were improved in sperm motility, swimming velocity, and beat frequency compared with other groups. In the second experiment, a medium containing sperm from swim-up method and outlet reservoir of our 7.5-mm microchannel chip was collected and mitochondrial activity of the sperm was determined by fluorescence microscopy. The sperm from the microchip had higher mitochondria activity (47.6%±6.0%) than the sperm from the swim-up method (23.6%±4.7%) (P<0.05). There were significant differences in rate of acrosome intactness between the swim-up method and the microchip (36.0%±4.1% vs. 66.8±2.1%, respectively, P<0.05). In the third experiment, we compared sperm penetration in the microchip-IVF system with a standard IVF method (droplet-IVF). The microchip-IVF group had the highest percentages of oocytes penetrated (82.2%±1.6% vs. 63.5%±2.4%) and monospermic oocytes (67.8%±3.4% vs. 42.4%±1.5%). In addition, early developmental competence of oocytes to the blastocyst stage was higher when the oocytes were inseminated in the microchip-IVF system compared with those inseminated in a standard droplet-IVF system. These results demonstrate that our microchip based on a sperm chemotaxis system is useful for motile sperm separation from frozen-thawed bull semen for IVF. Therefore, the optimized microchip system provides a good opportunity to sort
Men, Nguyen Thi; Kikuchi, Kazuhiro; Furusawa, Tadashi; Dang-Nguyen, Thanh Quang; Nakai, Michiko; Fukuda, Atsunori; Noguchi, Junko; Kaneko, Hiroyuki; Viet Linh, Nguyen; Xuan Nguyen, Bui; Tajima, Atsushi
Boar sperm freeze-dried with trehalose showed a protective effect against sperm DNA fragmentation. However, normal fertilization and embryonic development were not improved. Damaged sperm may activate maternal DNA repair genes when injected into oocytes. Therefore, we investigated the expression profile of some DNA repair genes in porcine oocytes after intra-cytoplasmic sperm injection. First, the expression levels of MGMT, UDG, XPC, MSH2, XRCC6 and RAD51 genes that are concerned with different types of DNA repair were examined in in vitro mature (IVM) oocytes injected with ejaculated sperm, or freeze-dried sperm with or without trehalose. Quantitative reverse transcription polymerase chain reaction revealed that expression of six DNA repair genes in the oocytes at 4 h after injection did not differ among the four groups. Next, we investigated the gene expression levels of these genes at different stages of maturation. The relative expression levels of UDG and XPC were significantly up-regulated in mature oocytes compared with earlier stages. Furthermore, there was an increased tendency in relative expression of MSH2 and RAD51. These results suggested two possible mechanisms that messenger RNA of DNA repair genes are either accumulated during IVM to be ready for fertilization or increased expression levels of DNA repair genes in oocytes caused by suboptimal IVM conditions.
Higaki, Shogo; Shimada, Manami; Kawamoto, Kazuaki; Todo, Takaaki; Kawasaki, Toshihiro; Tooyama, Ikuo; Fujioka, Yasuhiro; Sakai, Noriyoshi; Takada, Tatsuyuki
Many endemic fish species are threatened with extinction. Conservation strategies and the restoration of endemic fish after extinction must therefore be investigated. Although sperm cryopreservation is indispensable for the conservation of endangered fishes, the limited number of mature fish and limited availability (volume and period) of sperm from small endemic fish hinders the optimization and practical use of this material. In this report, we demonstrate the in vitro differentiation of fertile sperm from cryopreserved spermatogonia of juveniles of the endangered small cyprinid honmoroko (Gnathopogon caerulescens), which is endemic to Lake Biwa in Japan. The entire process of spermatogenesis was recapitulated in vitro using cryopreserved spermatogonia of non-spawning adult and juvenile fish. The differentiation of sperm from spermatogonia was captured as a time-lapse video and confirmed by 5-ethynyl-2′-deoxyuridine (EdU) incorporation into sperm. Fertility was demonstrated by artificial insemination. These results suggest that the combination of cryopreservation of spermatogonia and in vitro sperm differentiation will provide a new and promising strategy for the preservation of paternal genetic materials. PMID:28211534
Higaki, Shogo; Shimada, Manami; Kawamoto, Kazuaki; Todo, Takaaki; Kawasaki, Toshihiro; Tooyama, Ikuo; Fujioka, Yasuhiro; Sakai, Noriyoshi; Takada, Tatsuyuki
Many endemic fish species are threatened with extinction. Conservation strategies and the restoration of endemic fish after extinction must therefore be investigated. Although sperm cryopreservation is indispensable for the conservation of endangered fishes, the limited number of mature fish and limited availability (volume and period) of sperm from small endemic fish hinders the optimization and practical use of this material. In this report, we demonstrate the in vitro differentiation of fertile sperm from cryopreserved spermatogonia of juveniles of the endangered small cyprinid honmoroko (Gnathopogon caerulescens), which is endemic to Lake Biwa in Japan. The entire process of spermatogenesis was recapitulated in vitro using cryopreserved spermatogonia of non-spawning adult and juvenile fish. The differentiation of sperm from spermatogonia was captured as a time-lapse video and confirmed by 5-ethynyl-2‧-deoxyuridine (EdU) incorporation into sperm. Fertility was demonstrated by artificial insemination. These results suggest that the combination of cryopreservation of spermatogonia and in vitro sperm differentiation will provide a new and promising strategy for the preservation of paternal genetic materials.
Kennedy, Chelsey E; Krieger, Kari Beth; Sutovsky, Miriam; Xu, Wei; Vargovič, Peter; Didion, Bradley A; Ellersieck, Mark R; Hennessy, Madison E; Verstegen, John; Oko, Richard; Sutovsky, Peter
Post-acrosomal WW-domain binding protein (PAWP) is a signaling molecule located in the post-acrosomal sheath (PAS) of mammalian spermatozoa. We hypothesized that the proper integration of PAWP in the sperm PAS is reflective of bull-sperm quality and fertility. Cryopreserved semen samples from 298 sires of acceptable, but varied, fertility used in artificial insemination services were analyzed using immunofluorescence microscopy and flow cytometry for PAWP protein. In normal spermatozoa, PAWP fluorescence formed a regular band around the proximal PAS. Anomalies of PAWP labeling in defective spermatozoa were reflected in flow cytometry by varied intensities of PAWP-induced fluorescence. Distinct sperm phenotypes were also identified, including morphologically normal and some defective spermatozoa with moderate levels of PAWP; grossly defective spermatozoa with low/no PAWP; and defective spermatozoa with high PAWP. Analysis by ImageStream flow cytometry confirmed the prevalence of abnormal sperm phenotypes in the spermatozoa with abnormal PAWP content. Live/dead staining and video recording showed that some abnormal spermatozoa are viable and capable of progressive motility. Conventional flow-cytometric measurements of PAWP correlated significantly with semen quality and fertility parameters that reflect the sires' artificial insemination fertility, including secondary sperm morphology, conception rate, non-return rate, and residual value. A multiplex, flow-cytometric test detecting PAWP, aggresomes (ubiquitinated protein aggregates), and acrosomal integrity (peanut-agglutinin-lectin labeling) had a predictive value for conception rate, as demonstrated by step-wise regression analysis. We conclude that PAWP correlates with semen/fertility parameters used in the cattle artificial insemination industry, making PAWP a potential biomarker of bull fertility.
Sapanidou, V; Taitzoglou, I; Tsakmakidis, Ι; Kourtzelis, I; Fletouris, D; Theodoridis, A; Zervos, I; Tsantarliotou, M
Reactive oxygen species (ROS) production above critical levels affects the genetic and functional integrity of spermatozoa by causing oxidative stress. Spermatozoa are susceptible to oxidative stress in terms of motility and fertilization capacity. Crocin (crocetin di-gentiobiose ester), a main constituent of Crocus Sativus L. (saffron), is known for its antioxidant activity by scavenging ROS, especially superoxide anion. The aim of the present study is to evaluate the effect of crocin on the quality characteristics of spermatozoa and fertilization rate. Frozen-thawed and washed spermatozoa from four different bulls were incubated with three different concentrations of crocin (0.5, 1, and 2 mM), for 120 and 240 minutes, in the presence of a negative control, and were evaluated in terms of motility, viability, acrosomal status, DNA fragmentation index, intracellular ROS, and lipid peroxidation. The most potent concentration of crocin (1 mM) was also added in the fertilization medium to test its impact on fertilization outcome. The results indicate that the incubation of spermatozoa with 1 mM of crocin resulted in a statistically significant lower production of ROS, lower lipid peroxidation and in better maintenance of motility, viability, and acrosomal integrity, with a very small number of fragmented cells, compared to the control and the other treated groups (P < 0.05). Crocin concentration of 1 mM resulted in a significant increase of blastocyst rate, compared to the control group (P < 0.01). These data indicate that crocin (1 mM) improves bovine sperm quality and its fertilization capability, directly and/or indirectly, by modulating ROS concentration.
Chang, M C; Berkery, D; Laychock, S G; Schuel, H
Inhibition of the egg jelly induced acrosome reaction by delta 9-tetrahydrocannabinol (THC) is associated with the localized disruption of the nuclear envelope and the formation of lipid deposits in sea urchin sperm. This suggests that THC may activate phospholipase(s) within the sperm. We now report effects of THC on phospholipase A2 activity in homogenates of sea urchin sperm using 1-stearoyl-2-[1-14C]arachidonyl phosphatidylcholine as substrate. The release of radioactive arachidonic acid was measured after a 30-min incubation with the enzyme. In the absence of exogenous Ca2+, 100 microM THC produced a significant (P less than 0.001) increase in phospholipase A2 activity. THC activated phospholipase A2 in a concentration (1-100 microM) and time-dependent (0-30 min) manner. Exogenous calcium (10 mM) significantly augmented basal (P less than 0.001) and THC-stimulated (P less than 0.005) phospholipase A2 activity. Calcium chelators [ethylene glycol bis(beta-aminoethyl ether)N,N,N',N'-tetraacetic acid (EGTA) and 1,2-bis(O-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA)] inhibited the basal level of phospholipase A2 activity in the sperm homogenate, and prevented the activation of phospholipase A2 by THC. Submicromolar levels of free calcium ions were required for THC stimulation of phospholipase A2. Cannabinol which mimics the effects of THC on the acrosome reaction also activated phospholipase A2 in sperm homogenate. These results suggest that THC may alter lipid metabolism in sperm by activating calcium-dependent phospholipase A2. Putative metabolites derived from this process may inhibit the acrosome reaction and thereby reduce the fertilizing capacity of sea urchin sperm.
Marchlewska, Katarzyna; Filipiak, Eliza; Walczak-Jedrzejowska, Renata; Oszukowska, Elzbieta; Sobkiewicz, Slawomir; Wojt, Malgorzata; Chmiel, Jacek; Kula, Krzysztof; Slowikowska-Hilczer, Jolanta
Objective. To investigate sperm DNA fragmentation and sperm functional maturity in men from infertile couples (IC) and men with testicular germ cell tumor (TGCT). Materials and Methods. Semen samples were collected from 312 IC men and 23 men with TGCT before unilateral orchiectomy and oncological treatment. The sperm chromatin dispersion test was performed to determine DNA fragmentation index (DFI) and the ability of sperm to bind with hyaluronan (HA) was assessed. Results. In comparison with the IC men, the men with TGCT had a higher percentage of sperm with fragmented DNA (median 28% versus 21%; p < 0.01) and a lower percentage of HA-bound sperm (24% versus 66%; p < 0.001). Normal results of both analyses were observed in 24% of IC men and 4% of men with TGCT. Negative Spearman's correlations were found between DFI and the percentage of HA-bound sperm in the whole group and in IC subjects and those with TGCT analyzed separately. Conclusions. Approximately 76% of IC men and 96% with TGCT awaiting orchiectomy demonstrated DNA fragmentation and/or sperm immaturity. We therefore recommend sperm banking after unilateral orchiectomy, but before irradiation and chemotherapy; the use of such a deposit appears to be a better strategy to obtain functionally efficient sperms.
Filipiak, Eliza; Walczak-Jedrzejowska, Renata; Oszukowska, Elzbieta; Sobkiewicz, Slawomir; Wojt, Malgorzata; Chmiel, Jacek; Kula, Krzysztof; Slowikowska-Hilczer, Jolanta
Objective. To investigate sperm DNA fragmentation and sperm functional maturity in men from infertile couples (IC) and men with testicular germ cell tumor (TGCT). Materials and Methods. Semen samples were collected from 312 IC men and 23 men with TGCT before unilateral orchiectomy and oncological treatment. The sperm chromatin dispersion test was performed to determine DNA fragmentation index (DFI) and the ability of sperm to bind with hyaluronan (HA) was assessed. Results. In comparison with the IC men, the men with TGCT had a higher percentage of sperm with fragmented DNA (median 28% versus 21%; p < 0.01) and a lower percentage of HA-bound sperm (24% versus 66%; p < 0.001). Normal results of both analyses were observed in 24% of IC men and 4% of men with TGCT. Negative Spearman's correlations were found between DFI and the percentage of HA-bound sperm in the whole group and in IC subjects and those with TGCT analyzed separately. Conclusions. Approximately 76% of IC men and 96% with TGCT awaiting orchiectomy demonstrated DNA fragmentation and/or sperm immaturity. We therefore recommend sperm banking after unilateral orchiectomy, but before irradiation and chemotherapy; the use of such a deposit appears to be a better strategy to obtain functionally efficient sperms. PMID:27999814
Pinart, Elisabeth; Yeste, Marc; Prieto-Martínez, Noelia; Reixach, Josep; Bonet, Sergi
The present approach was designed to evaluate the extender effects on sperm quality and fertility of short-term refrigerated seminal doses from Landrace boars lodged in husbandry-controlled conditions. For this purpose, we analyzed the sperm quality of seminal doses diluted in short-term (Beltsville Thawing Solution) and extra-long-term (Duragen) extenders from Days 0 to 2 of storage at 17 °C during an 8-month period. Pregnancy rates and litter size were evaluated from double inseminations within an interval of 12 hours (36 and 48 hours of refrigeration) of multiparous females using seminal doses diluted in each extender type. Sperm quality was assessed from the analyses of sperm motility and kinetics, sperm viability, expressed as plasma and acrosome membrane integrity, membrane lipid disorder, intracellular calcium levels, and acrosin activity. Results indicated significant differences between the extenders in the sperm quality of seminal doses. Therefore, the seminal doses diluted in Duragen had higher percentages of progressive motile spermatozoa and membrane-intact spermatozoa than those diluted in Beltsville Thawing Solution throughout all the experimental months. Nevertheless, despite these differences in preserving the sperm quality, pregnancy rates (>90%) and litter sizes (>10 piglets born per litter) were similar between the extenders. Our results had great relevance from a practical point of view because they reported lack of an extender effect on the reproductive performance of seminal doses during short-tem storage.
Hodgson, Alan N; Hodgson, Valerie; Eckelbarger, Kevin J
The structure of the spermatozoa and spermatogenesis of the lottiid limpet Patelloida latistrigata is described by transmission electron microscopy. Although the lengths of the spermatozoa (about 60 μm) and their head region (about 12 μm) are similar to those of other patellogastropods, the structure of the sperm head and midpiece are very different. The head consists of an unusually large acrosome (about 11-μm long) with a broad posterior invagination that houses the relatively small nucleus. The midpiece mitochondria, which are rather elongate with large folded tubular cristae, are housed in a cytoplasmic sheath posterior to the nucleus. The proximal centriole is unusually elongate (about 2-μm long). The axoneme that emerges from the distal centriole is surrounded anteriorly by the cytoplasmic sheath in which the cytoplasmic side of the plasma membrane has electron-dense material. The flagellum is enlarged at its terminal end. Spermatogenesis is similar to that described for other patellogastropods. Patelloida latistrigata, therefore, has spermatozoa that seem to meet the morphological criteria of ent-aquasperm, which raises the question of whether fertilization is truly external in this limpet. However, it is also possible that the modifications to the sperm are linked to unknown specializations of the egg or egg envelope.
Guerrero, Adán; Wood, Christopher D; Nishigaki, Takuya; Carneiro, Jorge; Darszon, Alberto
Sperm chemotaxis is a long-term puzzle and most of our knowledge comes from studying marine animals that are external fertilizers. Sperm are attracted by diffusible chemical factors (chemoattractants) released from the egg which redirect their swimming paths towards their source. This redirection is driven by increases in flagellar curvature that correlate with transient flagellar Ca(2+) increases. Recent experimental and modelling results provide insights into the signal flow underlying the translation of an external chemical gradient into an intracellular molecular and motor response. A fundamental element of sea-urchin sperm chemotaxis lies in the ability of these cells to suppress Ca(2+)-mediated increases in flagellar curvature while experiencing an increasing chemoattractant gradient. The article considers this new evidence and summarizes the known underlying cellular mechanisms and behavioural strategies that sperm use to locate and fertilize the oocyte.
Maroto-Morales, Alejandro; García-Álvarez, Olga; Ramón, Manuel; Martínez-Pastor, Felipe; Fernández-Santos, M Rocío; Soler, A Josefa; Garde, José Julián
The spermatozoon is the most diverse cell type known and this diversity is considered to reflect differences in sperm function. How the diversity in sperm morphology arose during speciation and what role the different specializations play in sperm function, however, remain incompletely characterized. This work reviews the hypotheses proposed to explain sperm morphological evolution, with a focus on some aspects of sperm morphometric evaluation; the ability of morphometrics to predict sperm cryoresistance and male fertility is also discussed. For this, the evaluation of patterns of change of sperm head morphometry throughout a process, instead of the study of the morphometric characteristics of the sperm head at different stages, allows a better identification of the males with different sperm cryoconservation ability. These new approaches, together with more studies employing a greater number of individuals, are needed to obtain novel results concerning the role of sperm morphometry on sperm function. Future studies should aim at understanding the causes of sperm design diversity and the mechanisms that generate them, giving increased attention to other sperm structures besides the sperm head. The implementation of scientific and technological advances could benefit the simultaneous examination of sperm phenotype and sperm function, demonstrating that sperm morphometry could be a useful tool for sperm assessment. PMID:27678465
Zeng, Xu-Hui; Yang, Chengtao; Xia, Xiao-Ming; Liu, Min; Lingle, Christopher J
Following entry into the female reproductive tract, mammalian sperm undergo a maturation process termed capacitation that results in competence to fertilize ova. Associated with capacitation is an increase in membrane conductance to both Ca(2+) and K(+), leading to an elevation in cytosolic Ca(2+) critical for activation of hyperactivated swimming motility. In mice, the Ca(2+) conductance (alkalization-activated Ca(2+)-permeable sperm channel, CATSPER) arises from an ensemble of CATSPER subunits, whereas the K(+) conductance (sperm pH-regulated K(+) current, KSPER) arises from a pore-forming ion channel subunit encoded by the slo3 gene (SLO3) subunit. In the mouse, both CATSPER and KSPER are activated by cytosolic alkalization and a concerted activation of CATSPER and KSPER is likely a common facet of capacitation-associated increases in Ca(2+) and K(+) conductance among various mammalian species. The properties of heterologously expressed mouse SLO3 channels differ from native mouse KSPER current. Recently, a potential KSPER auxiliary subunit, leucine-rich-repeat-containing protein 52 (LRRC52), was identified in mouse sperm and shown to shift gating of SLO3 to be more equivalent to native KSPER. Here, we show that genetic KO of LRRC52 results in mice with severely impaired fertility. Activation of KSPER current in sperm lacking LRRC52 requires more positive voltages and higher pH than for WT KSPER. These results establish a critical role of LRRC52 in KSPER channels and demonstrate that loss of a non-pore-forming auxiliary subunit results in severe fertility impairment. Furthermore, through analysis of several genotypes that influence KSPER current properties we show that in vitro fertilization competence correlates with the net KSPER conductance available for activation under physiological conditions.
Concannon, P; Whaley, S; Lein, D; Wissler, R
Variation in canine gestation length was studied in a Beagle colony (n = 290) in which apparent gestation length, estimated as the interval from the day of first mating to the day of parturition, ranged from 57 to 72 days, and averaged 65.3 +/- 0.2 days. The interval from the day of the peak in luteinizing hormone (LH) to parturition was less variable and ranged from 64 to 66 days and averaged 65.1 +/- 0.1 days (n = 54). Apparent gestation lengths less than or equal to 61 days all resulted from mating greater than or equal to 3 days after the LH peak; those greater than or equal to 68 days all followed initial or single matings occurring greater than or equal to 2 days before the LH peak. Fertile single matings 3 days before the LH peak provided evidence that the potential postcoital fertile longevity of canine sperm is at least 6 days and thus contributed, along with variability in the onset of estrus, to the observed variation in apparent gestation length in the dog. The limited range in the interval from the day of the preovulatory LH peak to the day of parturition (64, 65, or 66 days) demonstrates a considerable regularity in the sequential events of gestation in the dog.
Bernabò, Nicola; Ordinelli, Alessandra; Di Agostino, Raffaele; Mattioli, Mauro; Barboni, Barbara
The rapid growth of published literature makes biomedical text mining increasingly invaluable for unpacking implicit knowledge hidden in unstructured text. We employed biomedical text mining and biological networks analyses to research the process of sperm egg recognition and binding (SERB). We selected from the literature the molecules expressed either on spermatozoa or on oocytes thought to be involved in SERB and, using an automated literature search software (Agilent Literature Search), we realized a network, SERBN, characterized by a hierarchical scale free and a small world topology. We used an integrated approach, either based on selection of hubs or by a cluster analysis, to discern the key molecules of SERB. We found that in most cases some of them are not directly situated on spermatozoa and oocyte, but are dispersed in oviductal fluid or embedded in exosomes present in the perivitelline space. To confirm and validate our results, we performed further analyses using STRING and Reactome FI software. Our findings underscore that the fertility is not a property of gametes in isolation, but rather depends on the functional integrity of the entire reproductive system. These observations collectively underscore the importance of integrative biology in exploring biological systems and in rethinking of fertility mechanisms in the light of this innovative approach.
Rodríguez-Villamil, P; Hoyos-Marulanda, V; Martins, J A M; Oliveira, A N; Aguiar, L H; Moreno, F B; Velho, A L M C S; Monteiro-Moreira, A C; Moreira, R A; Vasconcelos, I M; Bertolini, M; Moura, A A
The present study evaluated functional aspects of binder of sperm 1 (BSP1) in the bovine species. In a first experiment, cumulus-oocyte complexes (n = 1274) were incubated with frozen-thawed ejaculated sperm (18 hours) in Fert-TALP medium containing: heparin, 10, 20, or 40 μg/mL BSP1. Heparin followed by gelatin affinity chromatography was used for purification of BSP1 from bovine seminal vesicle fluid. With ejaculated sperm, cleavage rates were similar when Fert-TALP medium was incubated with heparin (74.1 ± 2.7%), 10 μg/mL BSP1 (77.8 ± 3.1%), or 20 μg/mL BSP1 (74 ± 2.0%). Day-7 blastocyst rates were equivalent after incubations with heparin (40.8 ± 5.0%) and 10 μg/mL BSP1 (34.1 ± 4.4%), but reduced after 20 μg/mL BSP1 (22.4 ± 2.9%) and 40 μg/mL BSP1 (19.3 ± 4.1%; P < 0.05). In the second experiment, cumulus-oocyte complexes (n = 1213) were incubated with frozen-thawed cauda epididymal sperm (18 hours) in Fert-TALP medium containing: no heparin, heparin, 10, 20, or 40 μg/mL. Cleavage and blastocyst rates were similar after treatments with heparin (68.5 ± 1.3% and 24.7 ± 3.2%, respectively) or without heparin (65.5 ± 1.8% and 27.3 ± 1.6%, respectively). Cleavage was higher after treatment with any BSP1 concentrations (74.2 ± 2.7%-79.0 ± 1.1%) than without heparin (P < 0.05). Also, cleavage was better after Fert-TALP medium incubation with 40 μg/mL BSP1 (79.0 ± 1.1%) than with heparin (68.5 ± 1.3%; P < 0.05). Embryo development was higher (P < 0.05) after treatment with 20 μg/mL BSP1 (35.6 ± 2.5%) and 40 μg/mL (41.1 ± 2%) than after incubations with heparin (24.7 ± 3.2%) or without heparin (27.3 ± 1.6%). Interestingly, BSP1 did not cause reductions in blastocyst rates after fertilization with epididymal sperm, as observed with ejaculated sperm. On the basis of immunocytochemistry, there was BSP1 binding to frozen-thawed ejaculated but not to epididymal sperm. Also, anti-BSP1 reaction remained on ejaculated sperm (as expected) and
Hunter, R H F; Gadea, J
This essay proposes that highly localized communication between free and bound spermatozoa in the caudal portion of the oviduct acts to regulate the numbers detaching from the epithelium and progressing to the site of fertilization close to the time of ovulation. Low initial sperm:egg ratios are essential for monospermic fertilization. Liberation of surface macromolecules and metabolic prompting from activated spermatozoa, together with altered patterns of sperm movement and dynamic differences in intracellular Ca(2+) ion status between neighboring sperm cells, would influence the progressive release of spermatozoa from the reservoir in the oviduct isthmus. Different intensities of preovulatory epithelial binding, reflecting a range of states in the sperm surface membranes and associated proteins, would provide a further explanation for a chronologically staggered periovulatory detachment of spermatozoa. Intimate sperm-sperm interactions within the confines of the oviduct isthmus offer a sensitive means of fine-tuning the vanguard of competent male gametes reaching the isthmo-ampullary junction.
Ozkosem, Burak; Feinstein, Sheldon I.; Fisher, Aron B.; O'Flaherty, Cristian
Oxidative stress, the imbalance between reactive oxygen species production and antioxidant defenses, is associated with male infertility. Peroxiredoxins (PRDXs) are antioxidant enzymes with a wide distribution in spermatozoa. PRDX6 is highly abundant and located in all subcellular compartments of the spermatozoon. Infertile men have lower levels of sperm PRDX6 associated with low sperm motility and high DNA damage. In order to better understand the role of PRDX6 in male reproduction, the aim of this study was to elucidate the impact of the lack of PRDX6 on male mouse fertility. Spermatozoa lacking PRDX6 showed significantly increased levels of cellular oxidative damage evidenced by high levels of lipid peroxidation, 8-hydroxy-deoxyguanosine (DNA oxidation), and protein oxidation (S-glutathionylation and carbonylation), lower sperm chromatin quality (high DNA fragmentation and low DNA compaction, due to low levels of protamination and a high percentage of free thiols), along with decreased sperm motility and impairment of capacitation as compared with wild-type (WT) spermatozoa. These manifestations of damage are exacerbated by tert-butyl hydroperoxide treatment in vivo. While WT males partially recovered the quality of their spermatozoa (in terms of motility and sperm DNA integrity), Prdx6−/− males showed higher levels of sperm damage (lower motility and chromatin integrity) 6 mo after the end of treatment. In conclusion, Prdx6−/− males are more vulnerable to oxidative stress than WT males, resulting in impairment of sperm quality and ability to fertilize the oocyte, compatible with the subfertility phenotype observed in these knockout mice. PMID:26792942
Liu, Chang-He; Dong, Hai-Bo; Ma, Dong-Li; Li, You-Wei; Han, Dong; Luo, Ming-Jiu; Chang, Zhong-Le; Tan, Jing-He
A specific problem in goat semen preservation is the detrimental effect of seminal plasma on sperm viability in extenders containing yolk or milk. Thus, the use of chemically defined extenders will have obvious advantages. Although previous studies indicate that the initial pH of an extender is crucial to sustain high sperm motility, changes in extender pH during long-term semen storage have not been observed. Monitoring extender pH at different times of semen storage and modeling its variation according to nonlinear models is thus important for protocol optimization for long-term liquid semen preservation. The present results showed that during long-term liquid storage of goat semen, both sperm motility and semen pH decreased gradually, and a strong correlation was observed between the two. Whereas increasing the initial extender pH from 6.04 to 6.25 or storage with stabilized pH improved, storage with artificially lowered pH impaired sperm motility. Extender renewal improved sperm motility by maintaining a stable pH. Sperm coating with chicken (Gallus gallus) egg yolk improved motility by increasing tolerance to pH decline. A new extender (n-mZAP) with a higher buffering capacity was formulated, and n-mZAP maintained higher sperm motility, membrane integrity and acrosome intactness than the currently used mZAP extender did. Goat semen liquid-stored for 12 d in n-mZAP produced pregnancy and kidding rates similar to those obtained with freshly collected semen following artificial insemination. In conclusion, maintenance of a stable pH during liquid semen storage dramatically improved sperm viability and fertilizing potential.
Carpino, A; Rago, V; Guido, C; Casaburi, I; Aquila, S
Recent studies have revealed that insulin, the main regulator of the glucose homeostasis in somatic cells, is expressed in human spermatozoa which are also able to secrete it. This study investigated the expression of insulin and insulin receptor beta in pig spermatozoa, at immunohistochemical protein and mRNA level. The immunofluorescence assay revealed that insulin and its receptor were co-localized in the sperm midpiece, while insulin was also detected in the acrosomal region. Western blot evidenced a 36 kDa band for insulin and a 95 kDa band for insulin receptor, such as reported in somatic cells. In addition, both insulin and insulin receptor transcripts were detected in pig spermatozoa. Interestingly, a possible biological role of the hormone was evidenced during pig sperm capacitation and acrosome reaction. In fact, the results showed that insulin (0.01 and 0.1 nm) can induce both the activities. A possible autocrine short loop of insulin in pig spermatozoa was suggested by the evaluation of the hormone secretion in both uncapacitated and capacitated spermatozoa. Furthermore, spontaneous sperm capacitation and acrosome reaction were stimulated by glucose and inhibited by the blockage of insulin release (nifedipine). In conclusion, this work has firstly demonstrated the expression of insulin and of its receptor, as well as the insulin secretion by pig spermatozoa, thereby suggesting an unexpected significance of the hormone in the acquisition of the male gamete fertilizing ability.
Siddique, Mohammad Abdul Momin; Butts, Ian Anthony Ernest; Psenicka, Martin; Linhart, Otomar
Standardization of fertilization protocols for sterlet Acipenser ruthenus is crucial for improving reproductive techniques and for conservation purposes. Our objectives were to determine the number of sperm (tested 430,000:1, 43,000:1, 4300:1, 430:1 sperm to egg) required to fertilize eggs and explore how pre-incubation of eggs in freshwater for 0min, 0.5min, 1min, and 10min interacts with different sperm ratios. Fertilization success ranged from 29.7% at 430:1 to 84.2% at 430,000:1. Pre-incubation time had no effect on fertilization success at 430,000:1 and 43,000:1 sperm to egg ratios, while it was significant at the 4300:1 and 430:1 ratios. The use of adequate experimental suboptimal sperm to egg ratio revealed a positive effect of pre-incubation time, such that at the 430:1 ratio, 0.5min pre-incubation increased the fertilization rate than 10min. At 0min pre-incubation the proportion of fertilized eggs increased at the 430,000:1 ratio, while at 1min fertilization increased at the 4300:1 ratio. At the 10min pre-incubation time, fertilization increased at the 43,000:1 ratio. Moreover, at the 0.5min pre-incubation time, the 43,000:1 ratio increased the fertilization rate than the 430:1 ratio. Generally, for 430:1 ratio, the fertilization rate is lower than in control. Transmission electron microscopy showed that pre-incubation of eggs in water for <10min does not trigger a cortical reaction or the formation of a perivitelline space. Results suggest that with a low sperm to egg ratio 0.5 to 1min pre-incubation of eggs in freshwater prior to fertilization can enhance fertilization rate of sterlet.
Peng, Xiongbo; Yan, Tingting; Sun, Mengxiang
Sperm nuclear migration during fertilization in Arabidopsis and rice has recently been found to be actin-dependent, but the driving force behind this actin cytoskeleton-dependent motion is unclear. Here, we confirmed that the actin-dependent sperm nuclei migration during fertilization is a conserved mechanism in plants. Using in vitro fertilization systems, we showed that a functional actin is also essential in maize and tobacco for sperm nuclei migration after gamete membrane fusion. Cytoskeleton depolymerization inhibitor treatments supported the view that sperm nuclei migration is actin-dependent but microtubule-independent in both egg cell and central cell during double fertilization. We further revealed that the actin-based motor myosin is not the driving force for sperm nuclear migration in maize and tobacco. The WASP-Arp2/3 complex signal cascade is shown here to be involved in the regulation of sperm nuclear migration in maize and tobacco. It is interesting that sperm nuclei migration within somatic cell also need WASP-Arp2/3 complex signal cascade and actin, suggesting that the mechanism of sperm nuclear migration is not gamete specific. PMID:28225074
Tanihara, Fuminori; Nakai, Michiko; Men, Nguyen Thi; Kato, Noriko; Kaneko, Hiroyuki; Noguchi, Junko; Otoi, Takeshige; Kikuchi, Kazuhiro
The zona pellucida (ZP) is considered to play important roles in the prevention of polyspermy in mammalian oocytes. However, in pigs we have shown that the presence of the ZP accelerates sperm penetration into the ooplasm during in vitro fertilization (IVF). In the present study, we investigated the effects of the ZP on sperm binding, acrosomal status, and functional exposure of IZUMO, a critical factor involved in sperm-egg fusion, during IVF in pigs. We evaluated the numbers and acrosomal statuses of sperm binding to the ZP and oolemma, and being present in the ZP and perivitelline space (PVS) using ZP-intact and ZP-free oocytes. More sperm bound to the ZP than to the oolemma. The average number of sperm present in the PVS was 0.44-0.51 per oocyte, and all sperm had lost their acrosomes. The proportion of sperm that were immunopositive for anti-IZUMO antibody was significantly higher after they were passing or had passed through the ZP. Furthermore, addition of anti-IZUMO antibody to the fertilization medium significantly inhibited the penetration of sperm into ZP-free oocytes. These results suggest that, in pigs, the ZP induces the acrosome reaction, which is associated with the functional exposure of IZUMO, resulting in completion of fertilization.
Yoon, Sungwon; Chang, Kyu-Tae; Cho, Hongsang; Moon, Jisang; Kim, Ju-Sung; Min, Sung-Hun; Koo, Deog-Bon; Lee, Sang-Rae; Kim, Sang-Hyun; Park, Ki-Eun; Park, Young Il; Kim, Ekyune
Although sperm hyaluronidase is thought to play an important role in mammalian fertilization, the molecular function underlying these steps remains largely unknown. In mouse models, sperm-specific SPAM1 and HYAL5 hyaluronidase are believed to function in both sperm penetration of the cumulus matrix and sperm-ZP binding. However, gene-targeting studies for SPAM1 or HYAL5 show that hyaluronidases are not essential for fertilization, despite the fact that exogenous hyaluronidase can disrupt the cumulus matrix. Therefore, to evaluate whether sperm hyaluronidase is essential for mammalian fertilization, it is necessary to generate HYAL5/SPAM1 double-knockout mice. However, generating double-knockout mice is very difficult because these two genes exist on the same chromosome. Recently, investigators have begun to employ the pig model system to study human disease due to its similarities to human anatomy and physiology. In this study, we confirmed that pig SPAM1 exists as a single copy gene on chromosome 18 and is specifically expressed in the testis. In addition, we expressed recombinant pig SPAM1 in human embryonic kidney 293 cells and showed that these enzymes possess hyaluronidase activity. We also demonstrated that a polyclonal antibody against pig sperm hyaluronidase inhibits sperm-egg interactions in an in vitro fertilization (IVF) assay. Our results suggest that pig SPAM1 may play a critical role in pig fertilization and that recombinant SPAM1 can disperse the oocyte-cumulus complex in an IVF assay.
Artini, P G; Casarosa, E; Carletti, E; Monteleone, P; Di Noia, A; Di Berardino, O M
It is a known fact that abnormal seminal liquid specimens contain abnormal amounts of oxygen free radicals and reactive oxygen species (ROS), and that the use of antioxidant molecules both in vivo and in vitro leads to improvement of semen quality in terms of motility, reduction in DNA damage, with obvious consequences on the fertilization potential. Myo-inositol has been observed to have anti-oxidant properties and be present in much greater concentrations specifically in seminal liquid than in the blood. Moreover, there seems to be a direct relationship between myo-inositol and mitochondrial membrane potential (MMP) and sperm motility. Studies performed in vivo have demonstrated that a dietary supplementation with myo-inositol in men undergoing assisted reproduction techniques may improve sperm quality and motility in oligoasthenospermia (OAT) patients. In the following study we utilized myo-inositol in vitro to verify its effect on semen quality in both normal and OAT patients undergoing in vitro fertilization (IVF) with respect to standard sperm medium. In vitro incubation of seminal liquid carried out using myo-inositol (Andrositol-Lab, Lo.Li. Pharma-Roma, Italy) at a concentration of 15 μl/ml improved progressive motility in both normospermia and OAT subjects. In our opinion, myo-inositol may prove to be a useful strategy to improve sperm preparation for clinical use in IVF.
Zhou, Yuchuan; Zheng, Min; Shi, Qixian; Zhang, Li; Zhen, Wei; Chen, Wenying; Zhang, Yonglian
Mammalian sperm capacitation is an essential prerequisite to fertilizion. Although progress had been made in understanding the physiology and biochemistry of capacitation, little is known about the potential roles of epididymal proteins during this process. Here we report that HongrES1, a new member of the SERPIN (serine proteinase inhibitor) family exclusively expressed in the rat cauda epididymis and up-regulated by androgen, is secreted into the lumen and covers the sperm head. Co-culture of caudal sperms with HongrES1 antibody in vitro resulted in a significant increase in the percentage of capacitated spermatozoa. Furthermore, the percentage of capacitated spermatozoa clearly increased in rats when HongrES1 was down-regulated by RNAi in vivo. Remarkably, knockdown of HongrES1 in vivo led to reduced fertility accompanied with deformed appearance of fetuses and pups. These results identify HongrES1 as a novel and critical molecule in the regulation of sperm capacitation and male fertility. PMID:19116669
Chung, Jean-Ju; Miki, Kiyoshi; Kim, Doory; Shim, Sang-Hee; Shi, Huanan F; Hwang, Jae Yeon; Cai, Xinjiang; Iseri, Yusuf; Zhuang, Xiaowei; Clapham, David E
We report that the Gm7068 (CatSpere) and Tex40 (CatSperz) genes encode novel subunits of a 9-subunit CatSper ion channel complex. Targeted disruption of CatSperz reduces CatSper current and sperm rheotactic efficiency in mice, resulting in severe male subfertility. Normally distributed in linear quadrilateral nanodomains along the flagellum, the complex lacking CatSperζ is disrupted at ~0.8 μm intervals along the flagellum. This disruption renders the proximal flagellum inflexible and alters the 3D flagellar envelope, thus preventing sperm from reorienting against fluid flow in vitro and efficiently migrating in vivo. Ejaculated CatSperz-null sperm cells retrieved from the mated female uterus partially rescue in vitro fertilization (IVF) that failed with epididymal spermatozoa alone. Human CatSperε is quadrilaterally arranged along the flagella, similar to the CatSper complex in mouse sperm. We speculate that the newly identified CatSperζ subunit is a late evolutionary adaptation to maximize fertilization inside the mammalian female reproductive tract. DOI: http://dx.doi.org/10.7554/eLife.23082.001 PMID:28226241
Gunawan, Asep; Kaewmala, Kanokwan; Uddin, Muhammad Jasim; Cinar, Mehmet Ulas; Tesfaye, Dawit; Phatsara, Chirawath; Tholen, Ernst; Looft, Christian; Schellander, Karl
Male fertility is impaired through the lack of ESR1 (Estrogen Receptor 1) but little is known about the ESR1 roles in boar spermatogenesis and fertility. Therefore, this research was aimed at investigating the association with sperm quality and boar fertility traits in a total of 300 boars both from purebred Pietrain and Pietrain × Hampshire crosses. A SNP in coding region of ESR1g.672C>T in exon 1 was associated with sperm motility (P<0.05) and plasma droplet rate (P<0.01) while the polymorphism in non-coding region of ESR1g.35756T>C in inton 1 was associated with non-return rate (P<0.05). Furthermore, to analyse the mRNA and protein expression of ESR1 in boar reproductive tissues, a total of six boars were divided into two groups [Group I (G-I) and Group II (G-II)], where G-I had relatively better sperm quality. ESR1 expression was higher in tissues collected from G-I boars than those of collected from G-II boars, and the difference in mRNA expression was significant (P<0.01) in head of epididymis. The ESR1 protein expression results from western blot coincided with the results of qRT-PCR. The ESR1 protein localization observed a strong staining in the cytoplasm of Sertoli cell in the testis, in the epithelial cells in head and tail of epididymis, in smooth muscle in tail of epididymis, and in the post acrosomal region and tail of the spermatozoa. These results will improve the understanding of the functions of the ESR1 in spermatogenesis within the reproductive tract and will shed light on ESR1 as a candidate in the selection of boar with good sperm quality and fertility.
Ansari, Mahdi; Zhandi, Mahdi; Kohram, Hamid; Zaghari, Mojtaba; Sadeghi, Mostafa; Sharafi, Mohsen
This study was conducted to investigate the effect of d-Aspartic acid (D-Asp) on post-thawed sperm quality, fertility and hatchability outcomes in male broiler breeders. Twenty 55-week-old roosters were selected and equally split into four groups (n = 5 rooster/group). Different daily D-Asp doses including 0 (D-0), 100 (D-100), 200 (D-200) or 300 (D-300) mg/kg BW were capsulated and individually administered for 12 weeks to roosters in each group. Semen samples were weekly collected from 7th to 12th week of experiment. Sperm quality from 7th to 11th week was evaluated in both fresh (total and forward motility and plasma membrane functionality) and post-thawed (total and forward motility, plasma membrane functionality, apoptosis status and mitochondrial activity) conditions. Also, collected semen samples on the 12th week were frozen and artificially inseminated to evaluate fertility and hatchability. The results from fresh condition showed that total and forward motility and plasma membrane functionality were significantly higher in D-200 compared to other groups. Also, interaction effect of time and treatment was not significant for all assessed parameters in fresh condition. In post-thawed condition, D-200 showed significantly higher total and forward motility, fertility and hatchability compared to other groups. The higher value for plasma membrane functionality and mitochondrial activity was observed in D-200 compared to D-0 and D300 groups. However, the percentage of live, early apoptotic and dead spermatozoa were not significantly affected by applied treatment in the current study. No significant difference for time and treat interaction effect was observed for all assessed parameters except forward motility. In conclusion, it seems that D-Asp administration could improve fresh and post-thawed sperm quality and post-thawed sperm fertility in male broiler breeders.
Tourmente, Maximiliano; Villar-Moya, Pilar; Varea-Sánchez, María; Luque-Larena, Juan J; Rial, Eduardo; Roldan, Eduardo R S
Sperm viability, acrosome integrity, motility, and swimming velocity are determinants of male fertility and exhibit an extreme degree of variation among closely related species. Many of these sperm parameters are associated with sperm ATP content, which has led to predictions of trade-offs between ATP content and sperm motility and velocity. Selective pressures imposed by sperm competition have been proposed as evolutionary causes of this pattern of diversity in sperm traits. Here, we examine variation in sperm viability, acrosome integrity, motility, swimming velocity, and ATP content over time, among 18 species of closely related muroid rodents, to address the following questions: (a) Do sperm from closely related species vary in ATP content after a period of incubation? (b) Are these differences in ATP levels related to differences in other sperm traits? (c) Are differences in ATP content and sperm performance over time explained by the levels of sperm competition in these species? Our results revealed a high degree of interspecific variability in changes in sperm ATP content, acrosome integrity, sperm motility and swimming velocity over time. Additionally, species with high sperm competition levels were able to maintain higher levels of sperm motility and faster sperm swimming velocity when they were incubated under conditions that support sperm survival. Furthermore, we show that the maintenance of such levels of sperm performance is correlated with the ability of sperm to sustain high concentrations of intracellular ATP over time. Thus, sperm competition may have an important role maximizing sperm metabolism and performance and, ultimately, the fertilizing capacity of spermatozoa.
Jaldety, Yael; Glick, Yair; Orr-Urtreger, Avi; Ickowicz, Debby; Gerber, Doron; Breitbart, Haim
To attain fertilization the spermatozoon binds to the egg zona pellucida (ZP) via sperm receptor(s) and undergoes an acrosome reaction (AR). Several sperm receptors have been described in the literature; however, the identity of this receptor is not yet certain. In this study, we suggest that the α7 nicotinic acetylcholine receptor (α7nAChR) might be a sperm receptor activated by ZP to induce epidermal growth factor receptor (EGFR)-mediated AR. We found that isolated ZP or α7 agonists induced the AR in sperm from WT but not α7-null spermatozoa, and the induced AR was inhibited by α7 or EGFR antagonists. Moreover, α7-null sperm showed very little binding to the egg, and microfluidic affinity in vitro assay clearly showed that α7nAChR, as well as EGFR, interacted with ZP3. Induction of EGFR activation and the AR by an α7 agonist was inhibited by a Src family kinase (SFK) inhibitor. In conclusion we suggest that activation of α7 by ZP leads to SFK-dependent EGFR activation, Ca2+ influx, and the acrosome reaction. PMID:22577141
Lo, Jennifer C. Y.; Jamsai, Duangporn; O'Connor, Anne E.; Borg, Claire; Clark, Brett J.; Whisstock, James C.; Field, Mark C.; Adams, Vicki; Ishikawa, Tomomoto; Aitken, R. John; Whittle, Belinda; Goodnow, Christopher C.; Ormandy, Christopher J.; O'Bryan, Moira K.
A significant percentage of young men are infertile and, for the majority, the underlying cause remains unknown. Male infertility is, however, frequently associated with defective sperm motility, wherein the sperm tail is a modified flagella/cilia. Conversely, a greater understanding of essential mechanisms involved in tail formation may offer contraceptive opportunities, or more broadly, therapeutic strategies for global cilia defects. Here we have identified Rab-like 2 (RABL2) as an essential requirement for sperm tail assembly and function. RABL2 is a member of a poorly characterized clade of the RAS GTPase superfamily. RABL2 is highly enriched within developing male germ cells, where it localizes to the mid-piece of the sperm tail. Lesser amounts of Rabl2 mRNA were observed in other tissues containing motile cilia. Using a co-immunoprecipitation approach and RABL2 affinity columns followed by immunochemistry, we demonstrated that within developing haploid germ cells RABL2 interacts with intra-flagella transport (IFT) proteins and delivers a specific set of effector (cargo) proteins, including key members of the glycolytic pathway, to the sperm tail. RABL2 binding to effector proteins is regulated by GTP. Perturbed RABL2 function, as exemplified by the Mot mouse line that contains a mutation in a critical protein–protein interaction domain, results in male sterility characterized by reduced sperm output, and sperm with aberrant motility and short tails. Our data demonstrate a novel function for the RABL protein family, an essential role for RABL2 in male fertility and a previously uncharacterised mechanism for protein delivery to the flagellum. PMID:23055941
While glycolysis is highly conserved, it is remarkable that several novel isozymes in this central metabolic pathway are found in mammalian sperm. Glyceraldehyde 3-phosphate dehydrogenase-S (GAPDS) is the product of a mouse gene expressed only during spermatogenesis and, like it...
D'Alessandro, A G; Martemucci, A G; Colonna, M A; Bellitti, A
A study was conducted to investigate the effects of prefreezing sperm concentration using two extenders on post-thaw survival and acrosomal status of ram spermatozoa (Experiment 1) and fertility after intrauterine insemination with differing doses of semen (Experiment 2). In autumn (Northern hemisphere), semen was collected by artificial vagina from 8 adult Leccese rams and ejaculates of good quality semen were pooled. Two extender systems for cryopreservation were considered, one based on milk-lactose egg yolk (Milk-LY) and the other based on tris-fructose egg yolk (Tris-FY). Experiment 1 (2 x 6 factorial scheme) examined the in vitro characteristics of spermatozoa in relation to the Milk-LY and Tris-FY extenders and six prefreezing sperm concentrations (50, 100, 200, 400, 500 and 800 x 10(6) spermatozoa/mL). Experiment 2 (2 x 4 factorial) evaluated the influence of the Milk-LY vs Tris-FY extenders and four doses (20, 40, 80 and 160 x 10(6) spermatozoa/0.25 mL) corresponding to prefreezing spermatozoa concentrations of 100, 200, 400 and 800 x 10(6) spermatozoa/mL, on fertility of ewes inseminated in uterus by laparoscope. Prefreezing sperm concentration influenced (P < 0.01) freezability of spermatozoa and affected negatively all the in vitro parameters at 800 x 10(6) spermatozoa/mL. Overall, Milk-LY tended to ensure higher viability and acrosomal integrity of spermatozoa after thawing at the intermediate sperm densities (range 100 to 500 x 10(6) spermatozoa/mL). At 500 x 10(6) spermatozoa/mL concentration corresponded the best condition for survival of spermatozoa (71.2%), acrosome integrity (71.5%) and acrosomal loss (6.0%). At the lowest sperm concentration (50 x 10(6) spermatozoa/mL), Tris-FY resulted in a higher survival rate than Milk-LY (61.3%, P < 0.05) and lower acrosomal loss (9.7%, P < 0.05). Milk-LY supported spermatozoa motility better than Tris-FY after incubation at sperm concentration between 50 and 400 x 10(6) spermatozoa/mL (0.05 > P < 0
Druart, Xavier; Gatti, Jean-Luc; Huet, Sylvie; Dacheux, Jean-Louis; Humblot, Patrice
Hypotonic resistance of boar spermatozoa was investigated by measuring the ratio of live/dead spermatozoa (SYBR-14/propidium iodide) by flow cytometry after hypotonic stress. The survival rate of ejaculated spermatozoa incubated in hypotonic solutions ranging from 3 to 330 mmol/kg followed a sigmoid curve that fitted a simple logistic model. The critical osmolality value (Osm(crit)) at which 50% of spermatozoa died was determined with this model. Hypotonic resistance of spermatozoa increased with temperature between 15 and 39 degrees C and decreased after hydrogen superoxide treatment, but was not modified during 8 days of preservation in Beltsville thawing solution. Hypotonic resistance markedly decreased during epididymal maturation and after ejaculation as Osm(crit) at 15 degrees C was 54.7+/-3.2, 68.5+/-10.6, 116.7+/-2.1 and 194.3+/-3.7 mmol/kg for the caput, corpus, cauda and ejaculated spermatozoa respectively. Hypo-osmotic stress of 100 mmol/kg revealed a sperm subpopulation exhibiting increased hypotonic resistance compared with the whole ejaculate (Osm(crit)=67.8+/-2.1 mmol/kg). Consistent differences were observed between lean and standard breeds (Pietrain versus Large White) and between boars within the same breed. According to data collected by artificial insemination centers during a large-scale field trial, hypotonic resistance of ejaculates was found to be positively correlated with in vivo fertility.
Shea, Jeremy M.; Boskovic, Ana; Derr, Alan G.; Bing, Xin Y.; Belleannee, Clemence; Kucukural, Alper; Serra, Ryan W.; Sun, Fengyun; Song, Lina; Carone, Benjamin R.; Ricci, Emiliano P.; Li, Xin Z.; Fauquier, Lucas; Moore, Melissa J.; Sullivan, Robert; Mello, Craig C.; Garber, Manuel; Rando, Oliver J.
Several recent studies link parental environments to phenotypes in subsequent generations. Here, we investigate the mechanism by which paternal diet affects offspring metabolism. Protein restriction in mice affects small RNA levels in mature sperm, with decreased let-7 levels and increased levels of 5’ fragments of glycine tRNAs. tRNA fragments are scarce in testicular sperm, but are gained as sperm mature in the epididymis. Epididymosomes – vesicles that fuse with sperm during epididymal transit – carry RNA payloads matching those of mature sperm, and deliver RNAs to immature sperm in vitro. Functionally, tRNA-Gly-GCC fragments repress genes associated with the endogenous retroelement MERVL, both in ES cells and embryos. Our results shed light on small RNA biogenesis, and its dietary regulation, during post-testicular sperm maturation, and link tRNA fragments to regulation of endogenous retroelements active in the preimplantation embryo. PMID:26721685
Sánchez-Gutiérrez, M; García-Montalvo, E A; Izquierdo-Vega, J A; Del Razo, L M
Selenium is an essential micronutrient for mammals, being integral part of antioxidant system. The aim of the study was to evaluate the effect of selenium deficiency on in vitro fertilization (IVF) capacity of spermatozoa and on oxidative stress in these cells. Male C57BL/6N mice were maintained on selenium-deficient or selenium-sufficient diets (0.02 or 0.2 ppm of selenium as selenomethionine, respectively) for 4 months. Liver glutathione peroxidase activity measurements were used to confirm selenium deficiency. Sperm quality and IVF capability among both groups were evaluated. To assess oxidative damage, lipid peroxidation as malondialdehyde production was determined in spermatozoa as well as the testes. Ultrastructural analyses of spermatozoa nuclei using transmission electron microscopy were also performed. The percentage of eggs fertilized with sperm from selenium-deficient mice was significantly decreased by approximately 67%. This reduced fertilization capacity was accompanied by increased levels of lipid peroxidation in both the testes and sperm, indicating that selenium deficiency induced oxidative stress. Consistent with this finding, spermatozoa from selenium-deficient animals exhibited altered chromatin condensation. Deficiency in dietary selenium decreases the reproductive potential of male mice and is associated with oxidative damage in spermatozoa.
Oliveira, R R; Rates, D M; Pugliesi, G; Ker, P G; Arruda, R P; Moraes, E A; Carvalho, G R
The use of cholesterol-loaded cyclodextrin (CLC) on semen cryopreservation has been related with better sperm viability in several species; however, the effect on fertility is not known in donkey semen. Ejaculates (n = 25) from five donkeys were diluted in S-MEDIUM with 0, 1, 2 or 3 mg of CLC/120 × 10(6) spermatozoa. Semen was frozen, and thawed samples were evaluated by computer-assisted sperm analyser system (CASA), supravital test, hyposmotic swelling test and fluorescent dyes to assess the integrity of sperm membranes. Mares (n = 60) were inseminated with frozen-thawed semen treated with the doses of 0 or 1 mg CLC. Percentages of sperm with progressive motility and with functional plasma membrane were greater (p < 0.05) in the CLC-treated groups than in the control. Percentages of intact plasma membrane and intact plasma membrane and acrosome detected by fluorescent dyes were also greater (p < 0.05) in CLC-treated groups. Although no difference (p > 0.05) in conception rates was detected between groups (control, 3/30, 10%; CLC-treated, 1/30, 3.3%), fertility was low for artificial insemination programs in mares. Therefore, we firstly demonstrated that frozen semen treated with CLC in S-MEDIA extender before freezing improves the in vitro sperm viability, but semen treated or not with CLC in S-MEDIUM extender results in a very low conception rate in mares inseminated with thawed donkey semen.
Safran, A; Reubinoff, B E; Porat-Katz, A; Werner, M; Friedler, S; Lewin, A
A binovular zona pellucida was found in two in-vitro fertilization (IVF) treatment cycles. In both cases, two oocytes of slightly unequal size were enclosed within a single zona pellucida, the larger oocyte appearing as a metaphase II oocyte while the smaller one as an immature oocyte with a germinal vesicle. Intracytoplasmic sperm injection performed in the mature oocyte of each pair led to normal fertilization and embryonic development in both cases. Results of genetic analysis performed by fluorescence in-situ hybridization in one of the two treatment cycles were consistent with a diploid chromosomal status of both the non-injected immature oocyte as well as the embryo which developed following the microinjection. These results indicate that, in this case, the binovular zona pellucida was most probably created when granulosa cells failed to separate two distinct oocytes during follicular formation. It may also imply that selective fertilization of a single mature oocyte in a binovular zona pellucida by intracytoplasmic sperm injection can lead to the development of a chromosomally balanced embryo and can prevent the undesired consequences that may result if the two oocytes are fertilized in the course of standard IVF.
Holden, S A; Fernandez-Fuertes, B; Murphy, C; Whelan, H; O'Gorman, A; Brennan, L; Butler, S T; Lonergan, P; Fair, S
The hypothesis of this study was that different in vitro parameters are required to predict the in vivo fertility of non-sorted (NS) and sex-sorted (SS) semen. Thus, the aim was to correlate in vitro bull sperm functional parameters (experiment 1) and seminal plasma composition (experiment 2) with pregnancy rates using 2 cohorts of bulls (NS and SS). Experiment 1: ejaculates from each bull (n = 3 ejaculates per bull; n = 6 bulls for both NS and SS) were assessed for motility, thermal stress tolerance and morphology using microscopy, and viability, osmotic resistance, mitochondrial membrane potential, and acrosome integrity using flow cytometry. Fertilizing ability was assessed using IVF. Experiment 2: ejaculates (n = 3 per bull; n = 8 and 6 bulls for NS and SS, respectively) were collected, seminal plasma harvested and frozen and later analyzed for amino acid and fatty acid composition using gas chromatography mass spectrometry. In the NS cohort of bulls, there was no correlation between pregnancy rate and any of the sperm functional parameters assessed. However, within the SS cohort, motility and viability were correlated with pregnancy rate (r = 0.84 and 0.80, respectively; P < 0.05). There was no correlation between IVF outcome and pregnancy rate in either the SS or NS cohort of bulls. In the NS cohort of bulls, concentrations of the amino acid isoleucine and the fatty acid tricosylic acid (C23:0) were correlated with pregnancy rate (r = 0.80 and 0.74, respectively; P < 0.05). Within the SS cohort of bulls, the amino acid glutamic acid and the fatty acid arachidic acid (C20:0) were correlated with pregnancy rate (r = 0.84 and 0.82, respectively; P < 0.05). In conclusion, this study suggests that different in vitro markers of fertility are required to predict the fertility of NS and SS sperm.
Roque, M; Sampaio, M; Salles, P G de Oliveira; Geber, S
Testicular germ cell tumours (TGCT) represent 1%-1.5% of all male neoplasms, and they have the highest prevalence among men between 15 and 35 years old. Synchronous bilateral disease is a rare presentation, and the ratio of metachronous to synchronous bilateral disease is about 4 : 1. Several studies have suggested a correlation between male infertility and testicular cancer, with a 20-fold increase in the incidence of testicular cancer in infertile patients compared with the general population. At the time of diagnosis, 50%-75% of patients with unilateral TGCT present with subfertility; almost 13% of the patients are azoospermic before treatment, and up to two-thirds of patients become azoospermic following adjuvant cancer therapies. Therefore, fertility preservation should be considered in all oncological treatments. The only available option to preserve the reproductive potential in azoospermic patients with testicular cancer is to perform an onco-testicular sperm extraction (onco-TESE) before cancer treatment. In this paper, we describe a rare case of a patient with synchronous bilateral testicular cancer and azoospermia who was submitted to onco-TESE, sperm cryopreservation, and which was followed by the delivery of a healthy baby after intracytoplasmic sperm injection (ICSI), emphasising the importance of fertility preservation in oncology patients.
A protein located on the surface of guinea pig sperm (PH-30) has been implicated in the process of sperm-egg fusion (Primakoff, P., H. Hyatt, and J. Tredick-Kline. 1987. J. Cell Biol. 104:141-149). In this paper we have assessed basic biochemical properties of PH-30 and have analyzed the molecular forms of PH-30 present at different stages of sperm maturation. We show the following: (a) PH-30 is an integral membrane glycoprotein; (b) it is composed of two tightly associated and immunologically distinct subunits; (c) both subunits are made as larger precursors; (d) processing of the two subunits occurs at different developmental stages; (e) the final processing step occurs in the region of the epididymis where sperm become fertilization competent; (f) processing can be mimicked in vitro; (g) processing exposes at least two new epitopes on PH-30-one of the newly exposed epitopes is recognized by a fusion-inhibitory monoclonal antibody. These results are discussed in terms of the possible role of PH-30 in mediating fusion with the egg plasma membrane. PMID:2114412
Chatiza, F P; Bartels, P; Nedambale, T L; Wagenaar, G M
The study assesses the possibility to estimate the potential fertility of post-thawed antelope (Antidorcas marsupialis), impala (Aepyceros melampus) and blesbok (Damaliscus dorcus phillipsi) epididymal sperm using homologous and heterologous IVF and the functioning of cattle IVF system to produce antelope embryos. Cauda epididymal sperm were collected from the antelope and cryopreserved under field conditions. In vitro matured domestic cow, blesbok and springbok oocytes were co-incubated in modified-Tyrode Lactate (m-TL) IVF media with springbok, impala and blesbok sperm for heterologous IVF and springbok and blesbok sperm for homologous IVF. A group of presumptive zygotes from each treatment were examined for sperm penetration and male pronuclear formation after 18h and the remainder were cultured and evaluated for embryo cleavage 22h later. The study shows that Modified Tyrode Lactate in vitro fertilization media supports survivability, capacitation and hyperactivation of springbok, impala and blesbok sperm. Springbok, impala and blesbok post-thawed epididymal spermatozoa are capable of fertilizing domestic cow oocytes under conditions that support domestic cattle IVF. Penetration, male pronuclear formation and embryo cleavage did not differ (p>0.05) between cow oocytes inseminated with sperm from springbok, impala or blesbok however these parameters were higher (p<0.05) for oocytes inseminated with bull sperm. Modified Tyrode Lactate IVF media supported homologous fertilization and embryo development in springbok and blesbok however did not support blastocyst development. These findings suggest that cattle provide a useful model for evaluating springbok, impala and blesbok post-thawed cauda epididymal sperm functionality. Domestic cattle embryo culture conditions need to be modified to promote blastosyst development in these antelope species. Such research provides an important tool in assisted reproductive technology development when high biological value
Karamysheva, Tatyana; Kosyakova, Nadezda; Guediche, Narjes; Liehr, Thomas
Small supernumerary marker chromosomes (sSMC) are found about four times more frequently in subfertile compared to the general population. The reason for this finding is still unclear. However, a connection of interphase architecture and genome function is suggested. And as we found in a previous study the presence of sSMC influences the nuclear architecture of peripheral blood cells and fibroblasts, we hypothesized that sSMC could have similar effects in sperm cells possibly leading to infertility. Here we applied for the first time 3-dimensional interphase fluorescence in situ hybridization (3D-FISH) to characterize the position of an extra-chromosome with respect to its sister- and selected other chromosomes (6, 15, 18, 19, 21, X, and Y) in sperm. Two sSMC carrier brothers with the identical sSMC derived from chromosome 15 were studied. One of the brothers was fertile and the other brother was infertile. Deviations from the normal positioning of chromosomes 21 and Y were seen in both brothers and for chromosomes 19 and X only in the infertile brother. Most striking were high rates of nullisomy and/or disomy for chromosomes 15, including sSMC (15), and 18 exclusively seen in the infertile brother. Overall, further evidence is provided that sSMC influence the nuclear architecture of a cell, including sperm. Further studies are necessary in sperm of fertile and infertile sSMC carriers to elaborate if the detected aneuploidy like that seen in the infertile brother is due to sSMC presence and disturbance of nuclear architecture.
Nayak, Swapnarani; Ferosekhan, Shajahan; Sahoo, Sangram Ketan; Sundaray, Jitendra Kumar; Jayasankar, Pallipuram; Barman, Hirak Kumar
Spermatogenesis is a highly co-ordinated and complex process. In vitro propagation of spermatogonial stem cells (SSCs) could provide an avenue in which to undertake in vivo studies of spermatogenesis. Very little information is known about the SSC biology of teleosts. In this study, collagenase-treated testicular cells of farmed catfish (Clarias batrachus, popularly known as magur) were purified by Ficoll gradient centrifugation followed by magnetic activated cell sorting using Thy1.2 (CD90.2) antibody to enrich for the spermatogonial cell population. The sorted spermatogonial cells were counted and gave ~3 × 106 cells from 6 × 106 pre-sorted cells. The purified cells were cultured in vitro for >2 months in L-15 medium containing fetal bovine serum (10%), carp serum (1%) and other supplements. Microscopic observations depicted typical morphological SSC features, bearing a larger nuclear compartment (with visible perinuclear bodies) within a thin rim of cytoplasm. Cells proliferated in vitro forming clumps/colonies. mRNA expression profiling by qPCR documented that proliferating cells were Plzf + and Pou2+, indicative of stem cells. From 60 days onwards of cultivation, the self-renewing population differentiated to produce spermatids (~6 × 107 on day 75). In vitro-produced sperm (2260 sperm/SSC) were free swimming in medium and hence motile (non-progressive) in nature. Of those, 2% were capable of fertilizing and generated healthy diploid fingerlings. Our documented evidence provides the basis for producing fertile magur sperm in vitro from cultured magur SSCs. Our established techniques of SSC propagation and in vitro sperm production together should trigger future in vivo experiments towards basic and applied biology research.
Gumułka, Małgorzata; Kapkowska, Ewa
The objective of this study was to determine the age effect of a broiler breeder flock on duration of fertility and number of spermatozoa penetrating the perivitelline layer overlying the germinal disc (SP/mm(2) GDIPVL). Moreover, in the second half of the flock's reproductive life, the effect of using ejaculates of young roosters (CA2) in artificial insemination (AI) on the above parameters of fertility was estimated. The commercial flock of broiler breeder hens (n = 100) was inseminated six times from 31 to 62 weeks of age. Additional inseminations, with ejaculates of roosters aged 31 and 36 weeks (CA2), were performed at 56 and 62 weeks of age. AI was performed during two consecutive days (D0 and D1) with an insemination dose of 125 x 10(6) spermatozoa/0.06 ml containing pooled ejaculates. The following parameters were studied: the effective and maximum duration of fertility (De and Dm), percent of fertility on different days after AI (FD10, FD15 and FD20), indices of duration of sperm penetration (DSP, SP < or = 3/GDIPVL), SP/mm(2) GDIPVL in eggs laid on successive days after insemination of hens at different age, and correlations between some fertility indices. Both for De and Dm, the highest values were noted after AI of the layers at 36 weeks of age (14.8 +/- 0.49 and 17.4 +/- 0.46 days, respectively), which were about 2 days longer than at 56 weeks. All fertility indices decreased gradually with age, starting from AI at peak egg production (31-36 weeks of age), while the use of ejaculates from CA2 did not help to increase them significantly. Correlation coefficients between SP/mm(2) GDIPVL and the other fertility indices were positive and highest for eggs laid on D3. It is concluded that high De values can be obtained from broiler breeders in adequate environmental and technological conditions of AI. It is suggested that the age-related decrease in fertility is more pronounced in females, in which the efficiency of sperm storage tubules decreases. The
Nabavi, Narges; Todehdehghan, Fatemeh; Shiravi, Abdollhossein
Background: Caffeine increases the CAMP production that stimulates spermatozoa movement. Caffeine is also used for induction of in vitro acrosome reaction in mammalian spermatozoa, an important step in achieving fertilization. Objective: The aim of this study was to assess the effect of caffeine on sperm's motility, vitality and laboratory fertilization rates in mouse in two T6 and M16 media. Materials and Methods: Epididymal mouse sperms were collected and treated by caffine in T6 and M16 media and their motility and vitality rates were evaluated. The pretreated sperms were added to oocytes in T6 and M16 media with and without caffeine and fertilization rates were recorded after 24 hours incubation. Results: Sperm's motility (81.7±1.67%) and vitality (88.7±1.33%) rates and percentage of fertilized oocytes (67.52±8.16%) in T6 medium plus caffeine compare to control group have increased and shown significant differences at p≤0.01. While the percentages of these parameters in M16 medium supplemented with caffeine were 68.3±6.01%, 78±6.11%, and 42.6±12.96 respectively and in comparison to control group (M16 without caffeine) have not shown significant differences. Conclusion: Addition of caffeine to T6 medium promotes the sperm's motility and vitality and enhances fertilization and early in vitro development of mouse embryos. This article extracted from M.Sc. thesis. (Narges Navabi) PMID:24639814
Ghirelli-Filho, Milton; de Marchi, Patricia Leme; Mafra, Fernanda Abani; Cavalcanti, Viviane; Christofolini, Denise Maria; Barbosa, Caio Parente; Bianco, Bianca; Glina, Sidney
ABSTRACT Objective To evaluate the incidence of Y-chromosome microdeletions in individuals born from vasectomized fathers who underwent vasectomy reversal or in vitro fertilization with sperm retrieval by epididymal aspiration (percutaneous epididymal sperm aspiration). Methods A case-control study comprising male children of couples in which the man had been previously vasectomized and chose vasectomy reversal (n=31) or in vitro fertilization with sperm retrieval by percutaneous epididymal sperm aspiration (n=30) to conceive new children, and a Control Group of male children of fertile men who had programmed vasectomies (n=60). Y-chromosome microdeletions research was performed by polymerase chain reaction on fathers and children, evaluating 20 regions of the chromosome. Results The results showed no Y-chromosome microdeletions in any of the studied subjects. The incidence of Y-chromosome microdeletions in individuals born from vasectomized fathers who underwent vasectomy reversal or in vitro fertilization with spermatozoa recovered by percutaneous epididymal sperm aspiration did not differ between the groups, and there was no difference between control subjects born from natural pregnancies or population incidence in fertile men. Conclusion We found no association considering microdeletions in the azoospermia factor region of the Y chromosome and assisted reproduction. We also found no correlation between these Y-chromosome microdeletions and vasectomies, which suggests that the assisted reproduction techniques do not increase the incidence of Y-chromosome microdeletions. PMID:28076602
Santi, Celia M; Martínez-López, Pablo; de la Vega-Beltrán, José Luis; Butler, Alice; Alisio, Arturo; Darszon, Alberto; Salkoff, Lawrence
Here we show a unique example of male infertility conferred by a gene knock-out of the sperm-specific, pH-dependent SLO3 potassium channel. In striking contrast to wild-type sperm which undergo membrane hyperpolarization during capacitation, we found that SLO3 mutant sperm undergo membrane depolarization. Several defects in SLO3 mutant sperm are evident under capacitating conditions, including impaired motility, a bent “hairpin” shape, and failure to undergo the acrosome reaction (AR). The failure of AR is rescued by valinomycin which hyperpolarizes mutant sperm. Thus SLO3 is the principal potassium channel responsible for capacitation-induced hyperpolarization, and membrane hyperpolarization is crucial to the AR. PMID:20138882
Background The C. elegans sperm protein SPE-42, a membrane protein of unknown structure and molecular function, is required for fertilization. Sperm from worms with spe-42 mutations appear normal but are unable to fertilize eggs. Sequence analysis revealed the presence of 8 conserved cysteine residues in the C-terminal cytoplasmic domain of this protein suggesting these residues form a zinc-coordinating RING finger structure. Results We made an in silico structural model of the SPE-42 RING finger domain based on primary sequence analysis and previously reported RING structures. To test the model, we created spe-42 transgenes coding for mutations in each of the 8 cysteine residues predicted to coordinate Zn++ ions in the RING finger motif. Transgenes were crossed into a spe-42 null background and protein function was measured by counting progeny. We found that all 8 cysteines are required for protein function. We also showed that sequence differences between the C-terminal 29 and 30 amino acids in C. elegans and C. briggsae SPE-42 following the RING finger domain are not responsible for the failure of the C. briggsae SPE-42 homolog to rescue C. elegans spe-42 mutants. Conclusions The results suggest that a bona fide RING domain is present at the C-terminus of the SPE-42 protein and that this motif is required for sperm-egg interactions during C. elegans fertilization. Our structural model of the RING domain provides a starting point for further structure-function analysis of this critical region of the protein. The C-terminal domain swap experiment suggests that the incompatibility between the C. elegans and C. briggsae SPE-42 proteins is caused by small amino acid differences outside the C-terminal domain. PMID:21345212
Weir, Laura K.; Grant, James W. A.
Sperm limitation is widespread across many animal species. Several mechanisms of sperm allocation have been proposed, including optimal allocation according to clutch size and equal allocation across females. However, considerably less effort has been directed at investigating the behavioural signals associated with sperm limitation in males, which may include mating rate and the intensity of courtship. We investigated whether multiple successive spawnings affect individual male fertilization success, mating rates and courtship rates in Japanese medaka (Oryzias latipes). Across an average of 17 spawning events per male, fertilization success decreased from 83.7 per cent for the first spawning to 40 per cent for the last spawning while courtship rate decreased from 3.4 to 1.5 min−1. Females appeared to respond to male sperm depletion by reducing clutch size. Our results suggest that male Japanese medaka are sperm-limited, and that courtship rate may be an honest indication of fertilization ability. PMID:20410031
Niu, Zhi-Hong; Shi, Hui-Juan; Zhang, Hui-Qin; Zhang, Ai-Jun; Sun, Yi-Juan; Feng, Yun
The aim of this study was to investigate whether the sperm chromatin structure assay (SCSA) results after swim-up are related to fertilization rates, embryo quality and pregnancy rates following in vitro fertilization (IVF). A total of 223 couples undergoing IVF in our hospital from October 2008 to September 2009 were included in this study. Data on the IVF process and sperm chromatin structure assay results were collected. Fertilization rate, embryo quality and IVF success rates of different DNA fragmentation index (DFI) subgroups and high DNA stainability (HDS) subgroups were compared. There were no significant differences in fertilization rate, clinical pregnancy or delivery rates between the DFI and HDS subgroups. However, the group with abnormal DFI had a lower good embryo rate. So, we concluded that the SCSA variables, either DFI or HDS after swim-up preparation, were not valuable in predicting fertilization failure or pregnancy rate, but an abnormal DFI meant a lower good embryo rate following IVF.
Vjugina, Ulyana; Zhu, Xiaoling; Oh, Eugene; Bracero, Nabal J; Evans, Janice P
The involvement of egg integrins in mammalian sperm-egg interactions has been controversial, with data from integrin inhibitor studies contrasting with evidence from knockouts showing that specific integrin subunits are not essential for fertility. An alpha(4)/alpha(9) (ITGA4/ITGA9) integrin subfamily member has been implicated in fertilization but not extensively examined, so we tested the following three hypotheses: 1) an ITGA4/ITGA9 integrin participates in sperm-egg interactions, 2) short-term acute knockdown by RNA interference of integrin subunits would result in a fertilization phenotype differing from that of chronic depletion via knockout, and 3) detection of a fertilization phenotype is sensitive to in vitro fertilization (IVF) assay conditions. We show that mouse and human eggs express the alpha(9) integrin subunit (ITGA9). RNA interference-mediated knockdown resulted in reduced levels of Itga9 mRNA and surface protein in mouse eggs. RNA interference attempts to knockdown ITGA9's likely beta partner, beta(1) (ITGB1), resulted in reduced Itgb1 mRNA but no reduction in ITGB1 surface protein. Therefore, studies using a function-blocking anti-ITGB1 antibody tested the hypothesis that ITGB1 participates in gamete interactions. Analyses of sperm-egg interactions with Itga9-knockdown eggs and anti-ITGB1 antibody-treated eggs in IVF assays using specific sperm:egg ratios revealed the following: 1) a reduction, but not complete loss, of sperm-egg binding and fusion was observed and 2) the reduction of sperm-egg binding and fusion was not detected in inseminations with high sperm:egg ratios. These data demonstrate that ITGA9 and ITGB1 participate in sperm-egg interactions but clearly are not the only molecules involved. This also shows that careful design of IVF parameters allows detection of deficiencies in gamete interactions.
González-Ortega, Claudia; Piña-Aguilar, Raul Eduardo; Cancino-Villareal, Patricia; Gutiérrez-Gutiérrez, Antonio Martin
In this report, we present a case of in vitro maturation (IVM) with surgical retrieved testicular sperm in a normo-ovulatory female. Human chorionic gonadotropin-primed IVM, testicular biopsy for sperm retrieval and intracytoplasmic sperm injection with fresh sperm were performed. Fourteen cumulus-oocyte complexes were obtained in germinal vesicle or metaphase I stage, eight oocytes reached metaphase II, seven presumptive zygotes were obtained, and three cleavage stages embryos in day 2 were transferred producing a singleton pregnancy. A single healthy newborn was obtained. Our results suggest that IVM may be an alternative for in vitro fertilization in normo-ovulatory women even if surgical retrieval of sperm is needed. Further research is required to depict contributing factors to the success of IVM in indications different from polycystic ovaries syndrome and the role of male gamete. PMID:27803591
Cryopreservation is the most efficient method for long-term preservation of mammalian sperm. However, freeze-thawing procedures may strongly impair the sperm function and survival and thus decrease the reproductive performance. In addition, the sperm resilience to withstand cryopreservation, also known as freezability, presents a high individual variability. The present work summarizes the principles of cryoinjury and the relevance of permeating and nonpermeating cryoprotective agents. Descriptions about sperm cryodamage are mainly focused on boar sperm, but reference to other mammalian species is also made when relevant. Main cryoinjuries not only regard to sperm motility and membrane integrity, but also to the degradation effect exerted by freeze-thawing on other important components for sperm fertilizing ability, such as mRNAs. After delving into the main differences between good and poor freezability boar ejaculates, those protein markers predicting the sperm ability to sustain cryopreservation are also mentioned. Moreover, factors that may influence sperm freezability, such as season, diet, breed, or ejaculate fractions are discussed, together with the effects of different additives, like seminal plasma and antioxidants. After briefly referring to the effects of long-term sperm preservation in frozen state and the reproductive performance of frozen-thawed boar sperm, this work speculates with new research horizons on the preservation of boar sperm, such as vitrification and freeze-drying.
... to the inside of the egg (cytoplasm), where fertilization takes place. Sometimes the sperm cannot penetrate the ... ICSI) can be done along with in vitro fertilization (IVF) to help fertilize the egg. During ICSI, ...
Spermatogenesis is vulnerable to disruption. Some sperm quality studies have reported unfavorable trends in male reproductive health indicators, and lifestyle exposures (LE) and excess body adiposity have been among the factors implicated. LE (cigarette smoking, alcohol consumpt...
Depalo, Raffaella; Falagario, Doriana; Masciandaro, Paola; Nardelli, Claudia; Vacca, Margherita Patrizia; Capuano, Pasquale; Specchia, Giorgina; Battaglia, Michele
Background: Anticancer treatments can impair male fertility. Cryopreservation of semen is an efficient procedure for fertility preservation. The aim of this study was to evaluate pre-freeze semen parameters among the various types of cancer, post-thaw sperm viability and reproductive outcome of samples used for assisted reproductive treatment (ART). Methods: This study included 721 men with cancer that had their semen cryopreserved in our bank in 1999–2015. Semen analysis and cryopreservation were performed before the start of antineoplastic treatment, according to the World Health Organization recommendations, European Commission and Italian law. Results: Among the 721 patient, 196 had seminoma of the testis, 173 Hodgkin’s lymphoma, 108 mixed testicular tumors, 89 germ cell tumors, 67 other tumors, 46 hematological tumors, and 42 non-Hodgkin’s lymphoma. The mean age of patients was significantly lower in Hodgkin’s lymphoma compared to other tumors. Statistically significant lower volume, sperm count and number of straws stored were observed respectively in Hodgkin’s lymphoma, mixed testicular tumor and hematological tumors. Nineteen patients used their frozen semen for 20 ART cycles. After thawing a significant reduction of motility and vitality was recorded. A lower fertilization rate was observed in patients affected by testicular tumor and lymphoma (35.42% and 50%) compared with other cancers (71.43%). No significant differences were observed in terms of cleavage and implantation rates. A total of five pregnancies and seven healthy newborns were achieved. Conclusions: Fertility preservation before gonadotoxic therapy is of great importance to patients with cancer and must be indicate before the start of treatment. PMID:27800030
Tavares, R S; Silva, A F; Lourenço, B; Almeida-Santos, T; Sousa, A P; Ramalho-Santos, J
Sperm chromatin/DNA damage can be measured by a variety of assays. However, it has been reported that these tests may lose prognostic value in Assisted Reproductive Technology (ART) cycles when assessed in post-prepared samples, possibly due to the normalizing effect promoted by sperm preparation procedures. We have recently implemented a modified version of the Diff-Quik staining assay that allows for the evaluation of human sperm chromatin status in native samples, together with standard sperm morphology assessment. However, the value of this parameter in terms of predicting in vitro fertilization (IVF) and Intracytoplasmic sperm injection (ICSI) outcomes after sperm selection is unknown. In this study, data from 138 couples undergoing in vitro fertilization (IVF) or Intracytoplasmic sperm injection (ICSI) treatments showed that sperm chromatin integrity was significantly improved after density gradient centrifugation and swim up (p < 0.001), but no correlations were found with fertilization or embryo development rates (p > 0.05). However, sperm samples presenting lower percentages of damaged chromatin were associated with better quality (Grade I) embryos in both ART procedures (p < 0.05) and clinical pregnancy among IVF couples (p < 0.05). Furthermore, regression analysis confirmed the clinical value of Diff-Quik staining in predicting IVF (but not ICSI) clinical pregnancy (OR: 0.927, 95% CI: 0.871-0.985, p = 0.015), and a threshold value of 34.25% for this parameter was established. The proportion of IVF couples achieving a clinical pregnancy was reduced 1.9-fold when the percentage of abnormal dark staining was ≥34.25% (p = 0.05). In conclusion, the Diff-Quik staining assay provides useful information regarding ART success, particularly in IVF cycles, where some degree of 'natural' sperm selection may occur; but not in ICSI, where sperm selection is operator dependent. This quick and low-cost assay is suggested as an alternative method to detect
Tomlinson, Mathew; Lewis, Sheena; Morroll, David
Reports on the influence of semen parameters on natural or assisted pregnancy are contradictory, suggesting that the many confounding variables which contribute to outcome have not been taken into account. However, it is possible to derive some consensus for both natural and assisted conception by focussing on studies which use WHO-recommended semen analysis on relatively large populations, applying appropriate statistics and accounting for 'female factors'. The concentration of progressively motile sperm has consistently been shown to be the most predictive factor with regard to outcome. Around 64% of studies suggest that a reasonable chance of success with artificial insemination requires at least 5 × 10⁶ motile sperm and this is supported by the WHO's revised reference range for natural conception. Sperm morphology remains controversial, with a lack of standardisation across centres, the adoption of ever-stricter scoring criteria and changing reference values. Antisperm antibodies do not appear to influence outcome independently of sperm motility and agglutination. Sperm DNA damage appears to be related to sperm quality, embryo development and pregnancy loss, yet there remains no consensus on the best testing procedures, clinical reference values and how patients with an adverse result should be managed. In conclusion, laboratories should continue to focus on reducing the uncertainty and improving the quality of their basic semen analysis.
Nuñez-Calonge, R.; Cortes, S.; Gago, M.; López, P.; Caballero-Peregrin, P.
Objective. To optimise the use of freeze/thaw testicular immotile spermatozoa from nonobstructive azoospermia patients and to analyse the outcome of intracytoplasmic sperm injection (ICSI) of such spermatozoa. Methods. Testicular specimens were retrieved and cryopreserved from forty patients with nonobstructive azoospermia and underwent one cycle with thawed spermatozoa (Group I) that led to pregnancy in sixteen cases. Twenty-four patients of group I underwent treatment with the same batch of thawed spermatozoa (Group II). For the first ICSI attempt, injection was performed when motile spermatozoa were found. In group II, injection was performed when maximum motility was reached. We compared mean of fertilization rate, embryo quality, clinical pregnancy rate and embryo implantation rate. Results. The mean percentage of motility was significantly higher in the group II than in the group I (18, 6 versus 8, 2). Group I showed a significant decrease in fertilization rates when compared with cryopreserved testicular spermatozoa in group II (54% versus 72%, P < 0.05). No difference was noted between the cleavage rate, embryo quality, clinical pregnancy rates and implantation rates among group II and I. Conclusion. Fecundation rate can be significantly improved after in-vitro culture and sperm selection of frozen-thawed immotile testicular spermatozoa in patients with nonobstructive azoospermia. PMID:22567413
Sarosiek, B; Glogowski, J; Cejko, B I; Kujawa, R; Szczepkowski, M; Kuźmiński, H; Dobosz, S; Kowalski, R K
β-N-Acetylglucosaminidase (β-NAGase) is an enzyme found in the sperm acrosome of numerous animal species including fish. Fish spermatozoa differ in their morphology including acrosome or acrosomeless aquasperm in chondrostean (e.g., sturgeon) and teleostean (e.g., rainbow trout). It has been shown that β-NAGase exists with high activity in both eggs and sperm of these species. The present study shows the potency of β-NAGase in fertilization. In rainbow trout, increase in sperm motility parameters (VAP and MOT) were observed in the presence of acetamide, an inhibitor for β-NAGase. In contrast, sperm motility parameters (VCL, VSL, VAP, MOT, and PRG) were reduced on the Siberian sturgeon in the presence of acetamide. The inhibition of the activity of β-NAGase in rainbow trout spermatozoa was led to a reduction in the number of fertilized eggs from 79% to 40%, whereas in sturgeon no change was observed in fertilization. Moreover, inhibition of β-NAGase in both spermatozoa and eggs of trout and sturgeon resulted in significant decrease in fertilization rate from 79% to 1% in rainbow trout and from 84% to 12% in Siberian sturgeon. Our research proves that β-NAGase can play a significant role in the fertilization process in teleosteans.
Chang, M C; Schuel, H
Pretreatment of Strongylocentrotus purpuratus sperm with delta 9-tetrahydrocannabinol (THC) prevents the triggering of the acrosome reaction by egg jelly. Examination of THC-treated sperm by transmission electron microscopy reveals that the membrane fusion reaction between the sperm plasma membrane and the acrosomal membrane is completely blocked. Electron-dense deposits are present in the subacrosomal fossa and in the centriolar fossa. The nuclear envelope is fragmented in close proximity to the electron-dense deposits. The electron-dense deposits are not bound by a limiting membrane, stain positively for lipid with thymol and farnesol, and disappear from THC-treated sperm that are extracted with chloroform:methanol (2:1) after glutaraldehyde fixation. The electron-dense deposits are lipid in nature and may be a hydrolytic product of the nuclear envelope. Electron-dense deposits are seen in sperm after 1-10 min treatment with 5-100 microM THC. The electron-dense deposits disappear after removal of THC from the sperm by washing, but the fragmented nuclear envelope in the subacrosomal fossa persists. Cannabidiol (CBD) and cannabinol (CBN) also inhibit the triggering of the acrosome reaction by egg jelly and produce ultrastructural changes in the sperm identical to those elicited by THC. Enhanced phospholipase activity stimulated by THC, CBD, and CBN may be the cause of the accumulation of lipid deposits in the sperm. Metabolites derived from this modification of membrane phospholipids may prevent triggering of the acrosome reaction by egg jelly and thereby inhibit fertilization.
Flowers, W L; Deller, F; Stewart, K R
The objective of this study was to evaluate relationships between common semen quality estimates including sperm motility, sperm morphology, spontaneous capacitation status and seminal plasma proteins and boar fertility using heterospermic inseminations and subsequent paternity testing. All boars (n=12) used in the study had excellent semen quality (≥70% normal sperm) that resulted in average farrowing rates and litter sizes of 88.9±0.7% and 11.7±0.1 pigs, respectively. Their ejaculates were combined to make heterospermic insemination doses in such a way that each boar was tested against all of his contemporaries. The proportion of piglets sired by each individual was used to separate boars into three fertility groups: High (71.6±4.8%; n=3); Medium (51.6±3.8%; n=6); and Low (25.2%±5.3%; n=3). Ejaculates from High fertility boars had more motile sperm with normal acrosomes that moved faster in a straight-line and were more likely to undergo an acrosome reaction (p≤0.05) compared with their counterparts in the Low fertility group. Ejaculates from High fertility boars contained the greatest concentrations of three seminal plasma proteins (25.9kD/5.9pI; 55.1kD/4.8pI; and 70.1kD/5.2pI; p≤0.05), whereas concentrations of a 19.1kD/6.8pI were highest in semen from Low fertility boars (p≤0.05). Multiple regression analyses indicated that concentrations of the 25.9kD/5.9pI seminal plasma protein explained 66% of the variation observed in the proportion of pigs sired within a litter among boars (p≤0.00001). These results demonstrate that heterospermic inseminations and subsequent paternity testing is an effective technique for defining relationships between common semen quality tests and fertility, especially in situations where reproductive performance of all the boars is high. Motility, normal acrosome morphology, average linear velocity of motile sperm, and the proportion of sperm capable of an acrosome reaction were all positively associated with boar
Channel x blue hybrid catfish is the desired genotype for US farm-raised catfish industry. Induced spawning of gravid channel catfish, followed by fertilization of stripped eggs with blue catfish sperm is the only reliable means to produce hybrid catfish embryos in hatcheries. Hybrid catfish fry p...
Casillas, Fahiel; Ducolomb, Yvonne; Lemus, Ana E; Cuello, Cristina; Betancourt, Miguel
This study was designed to evaluate the capacity of vitrified-warmed porcine immature oocytes to mature and to be fertilized using in vitro fertilization or intracytoplasmic sperm injection, and to determine the subsequent embryo development. Immature oocytes were vitrified using ethylene glycol and dimethylsulphoxide as cryoprotectants and the Cryolock method. After warming oocytes were cultured 44 h for maturation. Oocytes were randomly distributed in three treatment groups and subjected to in vitro fertilization (Experiment 1) or intracytoplasmic sperm injection (Experiment 2) procedures. The results indicate that the embryo development was higher in denuded oocytes co-cultured with granulosa cells (NkO-CC group) fertilized by in vitro fertilization or intracytoplasmic sperm injection compared to cumulus-cell oocyte complexes (COCs group), showing no significant differences with control. Vitrified denuded oocytes matured with a co-culture system NkO-CC group, displayed higher cleavage rate and blastocyst production than vitrified COCs group. Blastocysts were successfully obtained after IVF and ICSI procedures; however, the development to the blastocyst stage was better after IVF. These results show that the vitrification-warming media, the employment of a granulosa cell co-culture system and the Cryolock method during vitrification, increased the nuclear and cytoplasmic maturation of vitrified porcine immature oocytes. Further experiments are required to enhance porcine embryo production after vitrification.
into three categories of potency by taking into account the differences in the time course of action against spermatozoa and the dose response for...was carried out using the rabbit as a model of the human for such toxic effects. The exposure of rabbit spermatozoa to a series of compounds was...computer aided sperm analysis. An initial validation study was performed to evaluate the accuracy of CellTrak measurements for rabbit spermatozoa as
Maya-Soriano, M J; Taberner, E; Sabés-Alsina, M; Ramon, J; Rafel, O; Tusell, L; Piles, M; López-Béjar, M
High temperatures have negative effects on sperm quality leading to temporary or permanent sterility. The aim of the study was to assess the effect of long exposure to summer circadian heat stress cycles on sperm parameters and the motile subpopulation structure of epididymal sperm cells from rabbit bucks. Twelve White New Zealand rabbit bucks were exposed to a daily constant temperature of the thermoneutral zone (from 18 °C to 22 °C; control group) or exposed to a summer circadian heat stress cycles (30 °C, 3 h/day; heat stress group). Spermatozoa were flushed from the epididymis and assessed for sperm quality parameters at recovery. Sperm total motility and progressivity were negatively affected by high temperatures (P < 0.05), as were also specific motility parameters (curvilinear velocity, linear velocity, mean velocity, straightness coefficient, linearity coefficient, wobble coefficient, and frequency of head displacement; P < 0.05, but not the mean amplitude of lateral head displacement). Heat stress significantly increased the percentage of less-motile sperm subpopulations, although the percentage of the high-motile subpopulation was maintained, which is consistent with the fact that no effect was detected on fertility rates. However, prolificacy was reduced in females submitted to heat stress when inseminated by control bucks. In conclusion, our results suggest that environmental high temperatures are linked to changes in the proportion of motile sperm subpopulations of the epididymis, although fertility is still preserved despite the detrimental effects of heat stress. On the other hand, prolificacy seems to be affected by the negative effects of high temperatures, especially by altering female reproduction.
Guasto, Jeffrey; Juarez, Gabriel; Stocker, Roman
A wide variety of plants and animals reproduce sexually by releasing motile sperm that seek out a conspecific egg, for example in the reproductive tract for mammals or in the water column for externally fertilizing organisms. Sperm are aided in their quest by chemical cues, but must also contend with hydrodynamic forces, resulting from laminar flows in reproductive tracts or turbulence in aquatic habitats. To understand how velocity gradients affect motility, we subjected swimming sperm to a range of highly-controlled straining flows using a cross-flow microfluidic device. The motion of the cell body and flagellum were captured through high-speed video microscopy. The effects of flow on swimming are twofold. For moderate velocity gradients, flow simply advects and reorients cells, quenching their ability to cross streamlines. For high velocity gradients, fluid stresses hinder the internal bending of the flagellum, directly inhibiting motility. The transition between the two regimes is governed by the Sperm number, which compares the external viscous stresses with the internal elastic stresses. Ultimately, unraveling the role of flow in sperm motility will lead to a better understanding of population dynamics among aquatic organisms and infertility problems in humans.
Herrick, J R; Campbell, M; Levens, G; Moore, T; Benson, K; D'Agostino, J; West, G; Okeson, D M; Coke, R; Portacio, S C; Leiske, K; Kreider, C; Polumbo, P J; Swanson, W F
Studies of in vitro fertilization (IVF) and sperm cryopreservation have been conducted in several small cat species, but virtually no data exist for black-footed cats (Felis nigripes) (BFCs) or sand cats (Felis margarita) (SCs). The objectives of this study were 1) to compare in vitro motility and acrosome status of fresh and cryopreserved (frozen in pellets on dry ice or in straws in liquid nitrogen vapor) BFC and SC spermatozoa cultured in feline-optimized culture medium (FOCM) or Ham F-10, 2) to assess ovarian responsiveness in BFCs and SCs following exogenous gonadotropin treatment and laparoscopic oocyte recovery, and 3) to evaluate the fertility of fresh and frozen-thawed spermatozoa from both species using homologous and heterologous (domestic cat oocytes) IVF in the two culture media. Motility and acrosomal integrity of fresh and frozen-thawed spermatozoa from BFCs and SCs were similar (P > 0.05) in both media during 6 h of culture. Although effects were more pronounced in SCs, cryopreservation in straws was superior (P < 0.05) to cryopreservation in pellets for both species. Gonadotropin stimulation produced approximately 16 ovarian follicles per female, and >80% of recovered oocytes were of optimal (grade 1) quality. The BFC and SC spermatozoa fertilized 60.0%-79.4% of homologous and 37.7%-42.7% of heterologous oocytes in both culture media, with increased (P < 0.05) cleavage of homologous (SC) and heterologous (BFC and SC) oocytes in FOCM. These results provide the first information to date on the gamete biology of two imperiled cat species and further our capacity to apply reproductive technologies for their conservation.
Henkel, Ralf R
Spermatozoa are constantly exposed to the interphase between oxidation through high amounts of reactive oxygen species (ROS) and leukocytes, and reduction by means of scavengers and antioxidants. Considering the very special functions as being the only cells with such high polarization and exerting their functions outside the body, even in a different individual, the female genital tract, the membranes of these cells are chemically composed of an extraordinary high amount of polyunsaturated fatty acids. This in turn, renders them very susceptible to oxidative stress, which is defined as an imbalance between oxidation and reduction towards the oxidative status. As a result, ROS deriving from both leukocytes and the male germ cells themselves cause a process called ‘lipid peroxidation' and other damages to the sperm cell. On the other hand, a certain limited amount of ROS is essential in order to trigger vital physiological reactions in cells, including capacitation or the acrosome reaction in sperm. The treatment of patients with antioxidants to compensate the oxidative status caused by oxidative stress is highly debated as uncontrolled antioxidative treatment might derail the system towards the reduced status, which is also unphysiological and can even induce cancer. This paradox is called the ‘antioxidant paradox'. Therefore, a proper andrological diagnostic work-up, including the evaluation of ROS levels and the antioxidant capacity of the semen, has to be carried out beforehand, aimed at keeping the fine balance between oxidation and scavenging of vital amounts of ROS. PMID:21076433
Kumar, Lokesh; Yadav, Santosh K; Kushwaha, Bhavana; Pandey, Aastha; Sharma, Vikas; Verma, Vikas; Maikhuri, Jagdamba P; Rajender, Singh; Sharma, Vishnu L; Gupta, Gopal
Quiescent sperm survive in cauda epididymis for long periods of time under extreme crowding conditions and with a very limited energy substrate, while after ejaculation, motile sperm live for a much shorter period with an unlimited energy resource and without crowding. Thus, the energy metabolism in relation to the energy requirement of the two may be quite different. A simple physiological technique was evolved to collect viable quiescent sperm from rat cauda epididymis to compare its energy metabolism with motile sperm. Quiescent sperm exhibited 40%-60% higher activities of mitochondrial electron transport chain complexes I-IV and ATP synthase in comparison to motile sperm and accumulated Ca(2+) in the midpiece mitochondria to enhance oxidative phosphorylation (OxPhos). In contrast, motile sperm displayed up to 75% higher activities of key glycolytic enzymes and secreted more than two times the lactate than quiescent sperm. Quiescent sperm phosphorylated AMPK and MAPK-p38, while motile sperm phosphorylated AKT and MAPK/ERK. Glycolytic inhibitor iodoacetamide prevented motility activation of quiescent rat sperm and inhibited conception in rabbits more effectively than OxPhos uncoupler 2,4-dinitrophenol. Apparently, quiescent sperm employ the most energy efficient OxPhos to survive for extended periods of time under extreme conditions of nutrition and crowding. However, on motility initiation, sperm switch predominantly to glycolysis to cater to their high- and quick-energy requirement of much shorter periods. This study also presents a proof of concept for targeting sperm energy metabolism for contraception.
Schmitz, Lars; Motani, Ryosuke; Oufiero, Christopher E; Martin, Christopher H; McGee, Matthew D; Wainwright, Peter C
It has been hypothesized that sperm whale predation is the driver of eye size evolution in giant squid. Given that the eyes of giant squid have the size expected for a squid this big, it is likely that any enhanced ability of giant squid to detect whales is an exaptation tied to their body size. Future studies should target the mechanism behind the evolution of large body size, not eye size. Reconstructions of the evolutionary history of selective regime, eye size, optical performance, and body size will improve the understanding of the evolution of large eyes in large ocean animals.
Teperek, Marta; Simeone, Angela; Gaggioli, Vincent; Miyamoto, Kei; Allen, George E.; Erkek, Serap; Kwon, Taejoon; Marcotte, Edward M.; Zegerman, Philip; Bradshaw, Charles R.; Peters, Antoine H.F.M.; Gurdon, John B.; Jullien, Jerome
For a long time, it has been assumed that the only role of sperm at fertilization is to introduce the male genome into the egg. Recently, ideas have emerged that the epigenetic state of the sperm nucleus could influence transcription in the embryo. However, conflicting reports have challenged the existence of epigenetic marks on sperm genes, and there are no functional tests supporting the role of sperm epigenetic marking on embryonic gene expression. Here, we show that sperm is epigenetically programmed to regulate embryonic gene expression. By comparing the development of sperm- and spermatid-derived frog embryos, we show that the programming of sperm for successful development relates to its ability to regulate transcription of a set of developmentally important genes. During spermatid maturation into sperm, these genes lose H3K4me2/3 and retain H3K27me3 marks. Experimental removal of these epigenetic marks at fertilization de-regulates gene expression in the resulting embryos in a paternal chromatin-dependent manner. This demonstrates that epigenetic instructions delivered by the sperm at fertilization are required for correct regulation of gene expression in the future embryos. The epigenetic mechanisms of developmental programming revealed here are likely to relate to the mechanisms involved in transgenerational transmission of acquired traits. Understanding how parental experience can influence development of the progeny has broad potential for improving human health. PMID:27034506
Gualtieri, R; Barbato, V; Fiorentino, I; Braun, S; Rizos, D; Longobardi, S; Talevi, R
Reactive oxygen species (ROS) are physiologically generated during mitochondrial respiration and are involved in several signaling mechanisms. However, under pathological conditions, the concentration of ROS may exceed the antioxidant scavenging systems and subsequently lead to cell damage. High ROS levels have been proven to be detrimental to spermatozoa and furthermore compromise sperm function through lipid peroxidation, protein damage, and DNA strand breakage. Although the oral administration of antioxidants has been demonstrated to improve the semen quality in subfertile men, it is still a matter of debate if it can positively influence fertilization outcome and embryo developmental competence. Studies carried out in suitable animal models could resolve these fundamental questions. Hence, the main aims of the present study were to evaluate: (1) the effects of zinc, d-aspartate, and coenzyme Q10, included in the dietary supplement Genadis (Merck Serono), on bull sperm motility and DNA fragmentation; and (2) whether treated spermatozoa have a superior competence in fertilization and in supporting the development of healthy embryos. Our data indicate that this treatment prevents the loss of sperm motility and the rise in sperm DNA fragmentation over time. Moreover, blastocyst rate was found to be significantly higher in oocytes fertilized by treated spermatozoa, and these blastocysts harbored a significantly lower percentage of apoptotic cells.
Fácio, Cássio L; Previato, Lígia F; Machado-Paula, Ligiane A; Matheus, Paulo CS; Araújo Filho, Edilberto
Objective This study aimed to assess and compare sperm motility, concentration, and morphology recovery rates, before and after processing through sperm washing followed by swim-up or discontinuous density gradient centrifugation in normospermic individuals. Methods Fifty-eight semen samples were used in double intrauterine insemination procedures; 17 samples (group 1) were prepared with sperm washing followed by swim-up, and 41 (group 2) by discontinuous density gradient centrifugation. This prospective non-randomized study assessed seminal parameters before and after semen processing. A dependent t-test was used for the same technique to analyze seminal parameters before and after semen processing; an independent t-test was used to compare the results before and after processing for both techniques. Results The two techniques produced decreases in sample concentration (sperm washing followed by swim-up: P<0.000006; discontinuous density gradient centrifugation: P=0.008457) and increases in motility and normal morphology sperm rates after processing. The difference in sperm motility between the two techniques was not statistically significant. Sperm washing followed by swim-up had better morphology recovery rates than discontinuous density gradient centrifugation (P=0.0095); and the density gradient group had better concentration recovery rates than the swim-up group (P=0.0027). Conclusion The two methods successfully recovered the minimum sperm values needed to perform intrauterine insemination. Sperm washing followed by swim-up is indicated for semen with high sperm concentration and better morphology recovery rates. Discontinuous density gradient centrifugation produced improved concentration recovery rates. PMID:28050954
Yang, Yong; Lu, Xiangyi
Motile cilia and flagella exhibit many waveforms as outputs of dynein activation sequences on the highly conserved axoneme. Motility change of sperm in the reproductive tract is difficult to study and remains an important area of investigation. Sperm typically execute a sinusoidal waveform. Increased viscosity in the medium induces somewhat unusual arc-line and helical waveforms in some sperm. However, whether the latter two waveforms occur in vivo is not known. Using green fluorescence protein imaging, we show that Drosophila sperm in the uterus move in circular foci via arc-line waves, predominantly in a tail-leading orientation. From the uterus, a small fraction of the sperm enters the seminal receptacle (SR) in parallel formations. After sperm storage and coincident with fertilization of the egg, the sperm exit the SR via head-leading helical waves. Consistent with the observed bidirectional movements, the sperm show the ability to propagate both base-to-tip and tip-to-base flagellar waves. Numerous studies have shown that sperm motility is regulated by intraflagellar calcium concentrations; in particular, the Pkd2 calcium channel has been shown to affect sperm storage. Our analyses here suggest that Pkd2 is required for the sperm to adopt the correct waveform and movement orientation during SR entry. A working model for the sperm's SR entry movement is proposed. PMID:21293028
Ramaraj, P; Kessler, S P; Colmenares, C; Sen, G C
Although angiotensin-converting enzyme (ACE) has been studied primarily in the context of its role in blood pressure regulation, this widely distributed enzyme has many other physiological functions. The ACE gene encodes two isozymes. The somatic isozyme is expressed in many tissues, including vascular endothelial cells, renal epithelial cells, and testicular Leydig cells, whereas the testicular or germinal angiotensin-converting enzyme is expressed only in sperm. The ACE gene knockout mice lack both isozymes and they exhibit low blood pressure, kidney dysfunctions, and male infertility. Here, we report the use of a sperm-specific promoter and interbreeding of transgenic and gene knockout mice for generating a mouse strain that expressed ACE only in sperm. The experimental mice maintained the kidney defects of ACE-/- mice, but unlike the knockout strain, the males were fertile. Thus, we established that the role of ACE in male fertility is completely dependent on its exclusive expression in sperm. Our study clearly demonstrated how transgenic and knockout techniques can be combined for ascribing a specific physiological function to the expression of a multifunctional protein in a given tissue. PMID:9664078
KOYAMA, Keisuke; KANG, Sung-Sik; HUANG, Weiping; YANAGAWA, Yojiro; TAKAHASHI, Yoshiyuki; NAGANO, Masashi
ABSTRACT 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 − 0.297x2, 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. PMID:24430663
Koyama, Keisuke; Kang, Sung-Sik; Huang, Weiping; Yanagawa, Yojiro; Takahashi, Yoshiyuki; Nagano, Masashi
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.
Intracytoplasmic Sperm Injection Using DNA-Fragmented Sperm in Mice Negatively Affects Embryo-Derived Embryonic Stem Cells, Reduces the Fertility of Male Offspring and Induces Heritable Changes in Epialleles
Fernández-González, Raúl; Laguna-Barraza, Ricardo; Pericuesta, Eva; Calero, Antonia; Ramírez, Miguel Ángel; Gutiérrez-Adán, Alfonso
Intracytoplasmic sperm injection (ICSI) in mice using DNA-fragmented sperm (DFS) has been linked to an increased risk of genetic and epigenetic abnormalities both in embryos and offspring. This study examines: whether embryonic stem cells (ESCs) derived from DFS-ICSI embryos reflect the abnormalities observed in the DFS-ICSI progeny; the effect of DFS-ICSI on male fertility; and whether DFS-ICSI induces epigenetic changes that lead to a modified heritable phenotype. DFS-ICSI-produced embryos showed a low potential to generate ESC lines. However, these lines had normal karyotype accompanied by early gene expression alterations, though a normal expression pattern was observed after several passages. The fertility of males in the DFS-ICSI and control groups was compared by mating test. Sperm quantity, vaginal plug and pregnancy rates were significantly lower for the DFS-ICSI-produced males compared to in vivo-produced mice, while the number of females showing resorptions was higher. The epigenetic effects of DFS-ICSI were assessed by analyzing the phenotype rendered by the Axin1Fu allele, a locus that is highly sensitive to epigenetic perturbations. Oocytes were injected with spermatozoa from Axin1Fu/+ mice and the DFS-ICSI-generated embryos were transferred to females. A significantly higher proportion of pups expressed the active kinky-tail epiallele in the DFS-ICSI group than the controls. In conclusion: 1) ESCs cannot be used as a model of DFS-ICSI; 2) DFS-ICSI reduces sperm production and fertility in the male progeny; and 3) DFS-ICSI affects the postnatal expression of a defined epigenetically sensitive allele and this modification may be inherited across generations. PMID:24743851
TANAKA, Hiroshi; TAKEO, Shun; ABE, Takahito; KIN, Airi; SHIRASUNA, Koumei; KUWAYAMA, Takehito; IWATA, Hisataka
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
Gizzo, Salvatore; Ferrari, Bruno; Noventa, Marco; Ferrari, Emanuele; Patrelli, Tito Silvio; Gangemi, Michele; Nardelli, Giovanni Battista
Recent evidences identify Human Papillomavirus (HPV) sperm infection as a possible cause of male and couple infertility. It acts through different mechanisms at various steps of human conception and early gestational development. We performed a systematic review to assess the role of HPV semen infection on male and couple infertility. Analysis of available and eligible data does not permit us to fund clear evidences about clinical impact of HPV infection on fertility, although sperm parameters impairment is the most widely recognized effect. Regarding biomolecular implications, the available data are often conflicting. More studies are required to define the role of HPV sperm infection in clinical practice. The great majority of evidences are obtained by in vitro studies and this fact represents a limitation for the clinical management of HPVDNA sperm infection. Understanding the biological significance of HPV-DNA semen infection could permit us to explain most of the idiopathic male and couple infertility, leading to a better management of infertile men and a better timing for sperm banking storage before ART cycles.
Touré, Aminata; Lhuillier, Pierre; Gossen, Jan A; Kuil, Cor W; Lhôte, David; Jégou, Bernard; Escalier, Denise; Gacon, Gérard
The Slc26 family is a conserved family of anion transporters. In the human, their physiological relevance was highlighted with the discovery of pathogenic mutations in several Slc26 transporters that lead to distinctive clinical disorders (Pendred syndrome, deafness, diastrophic dysplasia, congenital chloride diarrhoea) that are related to the specific distribution of these genes. We previously identified TAT1 as a new family member (Slc26A8), very specifically expressed in male germ cells in both the human and the mouse. To investigate Tat1 function in the male germline, we generated mice with a targeted disruption of the Tat1 gene. Heterozygous and homozygous Tat1 mutant mice were indistinguishable from wild-type littermates concerning survival rate, general appearance and gross behaviour; however, Tat1 null males were sterile due to complete lack of sperm motility and reduced sperm fertilization potential. Ultra-structural analysis revealed defects in flagellar differentiation leading to an abnormal annulus, disorganization of the midpiece-principal piece junction, hairpin bending of the sperm tail with disruption of the axial structures, and abnormal mitochondrial sheath assembly. While ATP levels were normal, ATP consumption was strongly reduced in Tat1 null spermatozoa. Interestingly, Tat1 is located at the annulus, a septin-based circular structure connecting the midpiece to the principal piece. Altogether, our results indicate that Tat1 is a critical component of the sperm annulus that is essential for proper sperm tail differentiation and motility.
Buzatto, Bruno A; Thyer, Evan M; Roberts, J Dale; Simmons, Leigh W
Trade-offs between pre- and postcopulatory traits influence their evolution, and male expenditure on such traits is predicted to depend on the number of competitors, the benefits from investing in weapons, and the risk and intensity of sperm competition. Males of the chorusing frog Crinia georgiana use their arms as weapons in contest competition. Previously, we showed that increased numbers of rivals elevated the risk and intensity of sperm competition due to multimale amplexus, and caused a reversal in the direction of precopulatory selection on arm girth. Here, we focused on the factors affecting postcopulatory fertilization success during group spawning, using paternity data from natural choruses. Competitive fertilization success depended on the time spent amplexed and amplexus position. Relative testes size but not arm girth, contributed to fertilization success, but the effect of testes size depended on amplexus position. Our findings offer within species empirical support for recent sperm competition models that incorporate precopulatory male-male competition, and show why an understanding of the evolution of animal weapons requires a consideration of both pre- and postcopulatory episodes of sexual selection.
Fuhs, Corinna; Salmassi, Ali; Hedderich, Jürgen; Maass, Nicolai; Elessawy, Mohamed; Schmutzler, Andreas Gerd; Eckmann-Scholz, Christel
Cytokines are key modulators of the immune system and play an important role in the ovarian cycle. IL-18 levels in serum and follicular fluid were analyzed in women undergoing in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) treatment. The cohort study group consisted of 90 women, who were undergoing IVF or ICSI. The body mass index (BMI) was determined in all patients; IL-18 levels were measured in follicular fluid and serum. IL-18 levels in serum were significantly higher than those in follicular fluid. The median level in serum was 162.75 (80.21) pg/mL and that in follicular fluid, 138.24 (91.78) pg/mL. Women undergoing IVF treatment had lower IL-18 levels in serum (median, 151.19 (90.73) pg/mL) than those treated with ICSI (median, 163.57 (89.97) pg/mL). The correlation between IL-18 levels in serum and BMI was statistically significant, as well as the correlation between IL-18 levels in follicular fluid and ovarian stimulation response (p = 0.003). IL-18 was correlated with the response to ovarian stimulation and was the reason for successful pregnancy after IVF or ICSI treatment. Among other cytokines, IL-18 appears to be a promising prognostic marker of success in reproductive treatment and should be evaluated as such in further prospective studies. PMID:27747236
Background The assessment of the embryo quality is crucial to maintain an high pregnancy rate and to reduce the risk of multiple pregnancy. The evaluation of the pronuclear and nucleolar characteristics of human zygote have been proposed as an indicator of embryo development and chromosomal complement. The aim of the current study was to assess the role of pronuclear morphology evaluation in vitro fertilization (IVF) / intracytoplasmic sperm injection (ICSI) cycles. Methods Retrospective clinical analysis on 755 non-elective transfers of only one embryo (ET). Embryo assessment was performed in days 1 and 2. Clinical and biological data were recorded and analyzed according to embryo and/or pronuclear morphology. Results Both pronuclear and embryo morphology were significantly related to clinical pregnancy and live-birth rates. No significant difference in clinical pregnancy and live-birth rates was detected when the pronuclear and embryo morphology assessments were combined. Embryo morphology and maternal age were the only independent predictors of favorable outcome by logistic regression analysis. Conclusions Pronuclear evaluation is effective to select the best zygotes if ET is performed at day 1, whereas it did not improve the clinical outcomes when combined with embryo morphology evaluation in day 2. PMID:23282023
Gannier, A; Marty, G
Collision with vessels is a major cause of whale mortality in the Mediterranean Sea. The effect of non-spherical sound propagation effects on received levels (RL) was investigated for the sperm whale (Physeter macrocephalus). Relevant dive patterns were considered in each case and the RL were compared for two periods using a ray tracing software, the winter conditions and the summer stratified situation. RL were plotted as a function of time in a simulated collision case for two vessel speeds representative of a conventional merchant ship (15knots) and a fast-ferry (37knots). In almost all simulated cases, RL featured a brutal 23-31dB re 1μPa rise from below 100dB while the vessel approached the whale at close range. Summer situations were worse because this transition occurred at closer ranges, resulting in acoustic warning times of less than 30s in the fast ferry case. These results suggested that sperm whales could not be able to achieve an escape manoeuvre in a critical situation such as a fast vessel approaching under stratified waters conditions.
Gobin, Bruno; Ito, Fuminori; Billen, Johan; Peeters, Christian
Workers never mate in the large majority of ants, and they have usually lost the spermatheca, an organ specialized for long-term storage of sperm. Such 'non-sexual' workers are restricted to laying unfertilized eggs that give rise to males, and they cannot compete with the queens for the production of female offspring. In sharp contrast, workers in 200-300 species from phylogenetically basal subfamilies can reproduce sexually ('gamergates') because they retain a functional spermatheca like the queens. Importantly, 'non-sexual' workers in closely related species have a vestigial spermatheca. In this study, we compared the reservoir epithelium of 'sexual' workers to that of congeneric queens and 'non-sexual' workers using 21 species of Amblyoponinae, Ponerinae and Ectatomminae. We show that a pronounced thickening of the epithelium near the opening of the sperm duct is strictly associated with sexual reproduction in both castes. This is unlike 'non-sexual' workers in which this epithelium is always very thin, with few organelles; but all other structures remain intact. We discuss this evolutionary degeneration of the spermatheca and how it relates to behavioural or physiological modifications linked to mating. Our results help understand the loss of sexual reproduction by ant workers, a critical step in the extreme specialization of their phenotype.
Gobin, Bruno; Ito, Fuminori; Billen, Johan; Peeters, Christian
Workers never mate in the large majority of ants, and they have usually lost the spermatheca, an organ specialized for long-term storage of sperm. Such ‘non-sexual’ workers are restricted to laying unfertilized eggs that give rise to males, and they cannot compete with the queens for the production of female offspring. In sharp contrast, workers in 200 300 species from phylogenetically basal subfamilies can reproduce sexually (‘gamergates’) because they retain a functional spermatheca like the queens. Importantly, ‘non-sexual’ workers in closely related species have a vestigial spermatheca. In this study, we compared the reservoir epithelium of ‘sexual’ workers to that of congeneric queens and ‘non-sexual’ workers using 21 species of Amblyoponinae, Ponerinae and Ectatomminae. We show that a pronounced thickening of the epithelium near the opening of the sperm duct is strictly associated with sexual reproduction in both castes. This is unlike ‘non-sexual’ workers in which this epithelium is always very thin, with few organelles; but all other structures remain intact. We discuss this evolutionary degeneration of the spermatheca and how it relates to behavioural or physiological modifications linked to mating. Our results help understand the loss of sexual reproduction by ant workers, a critical step in the extreme specialization of their phenotype.
Komeya, Mitsuru; Kimura, Hiroshi; Nakamura, Hiroko; Yokonishi, Tetsuhiro; Sato, Takuya; Kojima, Kazuaki; Hayashi, Kazuaki; Katagiri, Kumiko; Yamanaka, Hiroyuki; Sanjo, Hiroyuki; Yao, Masahiro; Kamimura, Satoshi; Inoue, Kimiko; Ogonuki, Narumi; Ogura, Atsuo; Fujii, Teruo; Ogawa, Takehiko
In contrast to cell cultures, particularly to cell lines, tissues or organs removed from the body cannot be maintained for long in any culture conditions. Although it is apparent that in vivo regional homeostasis is facilitated by the microvascular system, mimicking such a system ex vivo is difficult and has not been proved effective. Using the culture system of mouse spermatogenesis, we addressed this issue and devised a simple microfluidic device in which a porous membrane separates a tissue from the flowing medium, conceptually imitating the in vivo relationship between the microvascular flow and surrounding tissue. Testis tissues cultured in this device successfully maintained spermatogenesis for 6 months. The produced sperm were functional to generate healthy offspring with micro-insemination. In addition, the tissue kept producing testosterone and responded to stimulation by luteinizing hormone. These data suggest that the microfluidic device successfully created in vivo-like conditions, in which testis tissue maintained its physiologic functions and homeostasis. The present model of the device, therefore, would provide a valuable foundation of future improvement of culture conditions for various tissues and organs, and revolutionize the organ culture method as a whole. PMID:26892171
Navarrete, Felipe A.; Alvau, Antonio; Lee, Hoi Chang; Levin, Lonny R.; Buck, Jochen; Leon, Patricia Martin-De; Santi, Celia M.; Krapf, Dario; Mager, Jesse; Fissore, Rafael A.; Salicioni, Ana M.; Darszon, Alberto; Visconti, Pablo E.
Mammalian sperm acquire fertilizing capacity in the female tract in a process called capacitation. At the molecular level, capacitation requires protein kinase A activation, changes in membrane potential and an increase in intracellular calcium. Inhibition of these pathways results in loss of fertilizing ability in vivo and in vitro. We demonstrated that transient incubation of mouse sperm with Ca2+ ionophore accelerated capacitation and rescued fertilizing capacity in sperm with inactivated PKA function. We now show that a pulse of Ca2+ ionophore induces fertilizing capacity in sperm from infertile CatSper1 (Ca2+ channel), Adcy10 (soluble adenylyl cyclase) and Slo3 (K+ channel) KO mice. In contrast, sperm from infertile mice lacking the Ca2+ efflux pump PMACA4 were not rescued. These results indicate that a transient increase in intracellular Ca2+ can overcome genetic infertility in mice and suggest this approach may prove adaptable to rescue sperm function in certain cases of human male infertility. PMID:27627854
Maselli, J; Hales, B F; Robaire, B
Treatment of testicular cancer includes the coadministration of bleomycin, etoposide and cis-platinum (BEP); however, along with its therapeutic benefit, BEP exposure results in extensive reproductive chemotoxic effects, including alterations to sperm chromatin integrity. As an intact paternal genome is essential for successful fertilization and embryogenesis, we assessed the effect of paternal exposure to BEP on sperm fertilization capacity and the resulting consequences on early embryonic gene expression. Adult male Brown Norway rats received a 9-week treatment with BEP or saline and then were sacrificed immediately or subject to a 9-week recovery period. HSP90AA1, HSP90B1 and PDIA3, involved in spermatozoa-egg interactions, were overexpressed in BEP-exposed spermatozoa after the 9-week treatment period; overexpression was also observed in spermatozoa from BEP-treated rats after 9 weeks of recovery. These proteins were localized to the plasma membrane of the sperm head; this localization may facilitate their role in spermatozoa-egg interactions as the highest staining intensities were observed in capacitated spermatozoa. The fertilization potential of spermatozoa was determined by in vitro fertilization with oocytes from unexposed naturally cycling female rats. Interestingly, the fertilization potential of spermatozoa following a 9-week recovery period from BEP treatment was significantly enhanced compared with controls. Moreover, stem cell transcription factors, involved in the regulation of a plethora of early embryonic events, were upregulated by more than twofold in eight-cell stage embryos sired by BEP recovery males compared with controls; this suggests that there are potential deleterious effects on embryo development well after termination of BEP exposure.
Barranco, Isabel; Tvarijonaviciute, Asta; Perez-Patiño, Cristina; Vicente-Carrillo, Alejandro; Parrilla, Inmaculada; Ceron, Jose J.; Martinez, Emilio A.; Rodriguez-Martinez, Heriberto; Roca, Jordi
Glutathione peroxidase-5 (GPX5) is an H2O2-scavenging enzyme identified in boar seminal plasma (SP). This study attempted to clarify its origin and role on sperm survival and fertility after artificial insemination (AI). GPX5 was expressed (Western blot and immunocytochemistry using a rabbit primary polyclonal antibody) in testes, epididymis and accessory sex glands (6 boars). SP-GPX5 concentration differed among boars (11 boars, P < 0.001), among ejaculates within boar (44 ejaculates, P < 0.001) and among portions within ejaculate (15 ejaculates). The first 10 mL of the sperm rich fraction (SRF, sperm-peak portion) had a significantly lower concentration (8.87 ± 0.78 ng/mL) than the rest of the SRF and the post-SRF (11.66 ± 0.79 and 12.37 ± 0.79 ng/mL, respectively, P < 0.005). Sperm motility of liquid-stored semen AI-doses (n = 44, at 15–17°C during 72h) declined faster in AI-doses with low concentrations of SP-GPX5 compared to those with high-levels. Boars (n = 11) with high SP-GPX5 showed higher farrowing rates and litter sizes than those with low SP-GPX5 (a total of 5,275 inseminated sows). In sum, GPX5 is widely expressed in the boar genital tract and its variable presence in SP shows a positive relationship with sperm quality and fertility outcomes of liquid-stored semen AI-doses. PMID:27627110
Barranco, Isabel; Tvarijonaviciute, Asta; Perez-Patiño, Cristina; Vicente-Carrillo, Alejandro; Parrilla, Inmaculada; Ceron, Jose J; Martinez, Emilio A; Rodriguez-Martinez, Heriberto; Roca, Jordi
Glutathione peroxidase-5 (GPX5) is an H2O2-scavenging enzyme identified in boar seminal plasma (SP). This study attempted to clarify its origin and role on sperm survival and fertility after artificial insemination (AI). GPX5 was expressed (Western blot and immunocytochemistry using a rabbit primary polyclonal antibody) in testes, epididymis and accessory sex glands (6 boars). SP-GPX5 concentration differed among boars (11 boars, P < 0.001), among ejaculates within boar (44 ejaculates, P < 0.001) and among portions within ejaculate (15 ejaculates). The first 10 mL of the sperm rich fraction (SRF, sperm-peak portion) had a significantly lower concentration (8.87 ± 0.78 ng/mL) than the rest of the SRF and the post-SRF (11.66 ± 0.79 and 12.37 ± 0.79 ng/mL, respectively, P < 0.005). Sperm motility of liquid-stored semen AI-doses (n = 44, at 15-17°C during 72h) declined faster in AI-doses with low concentrations of SP-GPX5 compared to those with high-levels. Boars (n = 11) with high SP-GPX5 showed higher farrowing rates and litter sizes than those with low SP-GPX5 (a total of 5,275 inseminated sows). In sum, GPX5 is widely expressed in the boar genital tract and its variable presence in SP shows a positive relationship with sperm quality and fertility outcomes of liquid-stored semen AI-doses.
Inoue, Naokazu; Ikawa, Masahito; Okabe, Masaru
An average human ejaculate contains over 100 million sperm, but only a few succeed in accomplishing the journey to an egg by migration through the female reproductive tract. Among these few sperm, only one participates in fertilization. There might be an ingenious molecular mechanism to ensure that the very best sperm fertilize an egg. However, recent gene disruption experiments in mice have revealed that many factors previously described as important for fertilization are largely dispensable. One could argue that the fertilization mechanism is made robust against gene disruptions. However, this is not likely, as there are already six different gene-disrupted mouse lines (Calmegin, Adam1a, Adam2, Adam3, Ace and Pgap1), all of which result in male sterility. The sperm from these animals are known to have defective zona-binding ability and at the same time lose oviduct-migrating ability. Concerning sperm-zona binding, the widely accepted involvement of sugar moiety on zona pellucida 3 (ZP3) is indicated to be dispensable by gene disruption experiments. Thus, the landscape of the mechanism of fertilization is revolving considerably. In the sperm-egg fusion process, CD9 on egg and IZUMO1 on sperm have emerged as essential factors. This review focuses on the mechanism of fertilization elucidated by gene-manipulated animals.
Schatten, Heide; Schatten, Gerald
It is noted that microfilaments are essential for incorporation of sperm in sea urchins and for pronuclear apposition in mice. The ability of sea urchin sperm to fertilize eggs is lowered by latrunculin, giving evidence that acrosomal microfilaments are of importance to the process of fertilization. Due to the uncertainty regarding the presence of microfilaments in various mammalian sperm, it is interesting that latrunculin does not noticeably affect the ability of mouse sperm to fertilize oocytes. The movements of the sperm and egg nuclei at the time of sea urchin fertilization are dependent on microtubules arranged into a radial monastral array (the sperm aster). In the mouse egg, microtubule activity is also required during pronuclear apposition, but they are arranged by a number of egg cytoplasmic sites. Results of the investigations show that both microtubules and microfilaments are necessary for the successful completion of fertilization in both mice and sea urchins, but at different stages. Also, it is demonstrated that centrosomes are contributed by the sperm in the process of sea urchin fertilization, but in mammals they may be inherited maternally.
Krishnakumar, S; Whiteside, D; Dance, A; Elkin, B; Thundathil, J
The objective of this study was to determine the duration for which sperm from the North American bison (Bison bison) could be chilled prior to being cryopreserved, without compromising post- thaw sperm quality. This would permit transport of samples collected remotely, to the laboratory (at 4°C) for cryopreservation. Epididymal sperm from plains bison (n = 11) and ejaculated sperm from wood bison (n = 3) were collected, extended and held at 4°C for extended periods of time. At intervals, an aliquot was cryopreserved. Post-thaw sperm motion characteristics were evaluated by computer assisted sperm analysis. Representative plains bison sperm samples (n = 3) were evaluated for their in vitro fertilizing ability in a heterologous system using bovine oocytes. There was no statistical difference in total and progressive motility of plains bison epididymal sperm when cryopreserved after chilling for 24, 48 or 72 h. For wood bison ejaculated sperm, there was no difference in total and progressive motility for sperm cryopreserved following 24 or 48 h of chilling. However, one of the three bulls showed significantly poorer fertilization (based on cleavage rate) with sperm chilled for 72 compared to 24 and 48 h prior to freezing. In conclusion, plains bison epididymal sperm can be chilled for 72 h and wood bison ejaculated sperm can be chilled for at least 48 h prior to cryopreservation without compromising post-thaw sperm motility, while heterologous in vitro fertilization (IVF) assay indicated a between-bull variation in the in vitro fertilizing ability of sperm chilled for an extended duration before cryopreservation.
Brown, Sean G.; Publicover, Stephen J.; Mansell, Steven A.; Lishko, Polina V.; Williams, Hannah L.; Ramalingam, Mythili; Wilson, Stuart M.; Barratt, Christopher L.R.; Sutton, Keith A.; Da Silva, Sarah Martins
STUDY QUESTION Are significant abnormalities in outward (K+) conductance and resting membrane potential (Vm) present in the spermatozoa of patients undertaking IVF and ICSI and if so, what is their functional effect on fertilization success? SUMMARY ANSWER Negligible outward conductance (≈5% of patients) or an enhanced inward conductance (≈4% of patients), both of which caused depolarization of Vm, were associated with a low rate of fertilization following IVF. WHAT IS KNOWN ALREADY Sperm-specific potassium channel knockout mice are infertile with defects in sperm function, suggesting that these channels are essential for fertility. These observations suggest that malfunction of K+ channels in human spermatozoa might contribute significantly to the occurrence of subfertility in men. However, remarkably little is known of the nature of K+ channels in human spermatozoa or the incidence and functional consequences of K+ channel defects. STUDY DESIGN, SIZE AND DURATION Spermatozoa were obtained from healthy volunteer research donors and subfertile IVF and ICSI patients attending a hospital assisted reproductive techniques clinic between May 2013 and December 2015. In total, 40 IVF patients, 41 ICSI patients and 26 normozoospermic donors took part in the study. PARTICIPANTS/MATERIALS, SETTING, METHODS Samples were examined using electrophysiology (whole-cell patch clamping). Where abnormal electrophysiological characteristics were identified, spermatozoa were further examined for Ca2+ influx induced by progesterone and penetration into viscous media if sufficient sample was available. Full exome sequencing was performed to specifically evaluate potassium calcium-activated channel subfamily M α 1 (KCNMA1), potassium calcium-activated channel subfamily U member 1 (KCNU1) and leucine-rich repeat containing 52 (LRRC52) genes and others associated with K+ signalling. In IVF patients, comparison with fertilization rates was done to assess the functional significance of
Tomášek, Oldřich; Albrechtová, Jana; Němcová, Martina; Opatová, Pavlína; Albrecht, Tomáš
It has been hypothesized that carotenoid-based sexual ornamentation signals male fertility and sperm competitive ability as both ornamentation and sperm traits may be co-affected by oxidative stress, resulting in positive covariation (the 'redox-based phenotype-linked fertility hypothesis'; redox-based PLFH). On the other hand, the 'sperm competition theory' (SCT) predicts a trade-off between precopulatory and postcopulatory traits. Here, we manipulate oxidative status (using diquat dibromide) and carotenoid availability in adult zebra finch (Taeniopygia guttata) males in order to test whether carotenoid-based beak ornamentation signals, or is traded off against, sperm resistance to oxidative challenge. Initial beak colouration, but not its change during the experiment, was associated with effect of oxidative challenge on sperm velocity, such that more intense colouration predicted an increase in sperm velocity under control conditions but a decline under oxidative challenge. This suggests a long-term trade-off between ornament expression and sperm resistance to oxidative challenge. Shortening of the sperm midpiece following oxidative challenge further suggests that redox homeostasis may constrain sperm morphometry. Carotenoid supplementation resulted in fewer sperm abnormalities but had no effect on other sperm traits. Overall, our data challenge the redox-based PLFH, partially support the SCT and highlight the importance of carotenoids for normal sperm morphology.
Wu, Jen-Kuei; Chen, Peng-Chun; Lin, Yu-Nan; Wang, Chia-Woei; Pan, Li-Chern; Tseng, Fan-Gang
In this paper, we propose a microfluidic device capable of generating a retarding flow field for the sorting and separation of human motile sperm in a high-throughput manner. The proposed sorting/separation process begins with a rapid flow field in a straight-flow zone to carry sperm into a sorting zone to maintain the sperm's mobility. The sorting zone consists of a diffuser-type sperm sorter to differentiate sperm with different motilities based on the flowing upstream nature of human sperm in a retarding flow field. The dead sperm will then be separated from the live ones by passing through a dumbbell flow field to the outlet for disposal. The proposed flowing upstream sperm sorter (FUSS) is designed to imitate the selection mechanism found in the female body when sperm swim into the uterus. The experimental results demonstrate the utility of this device with regard to throughput (approximately 200 000 sperm per minute and a maximum of 200 million cells per mL), efficiency (90% of selected sperm are mobile), and the ability to select sperm with high motility (∼20% of sperm with a velocity exceeding 120 μm s(-1)). The proposed device is suitable for intrauterine insemination as well as in vitro fertilization thanks to the highly efficient sorting process not interfering with the natural function and energy resource of human sperm.
Ferramosca, Alessandra; Zara, Vincenzo
After ejaculation, the mammalian male gamete must undergo the capacitation process, which is a prerequisite for egg fertilization. The bioenergetics of sperm capacitation is poorly understood despite its fundamental role in sustaining the biochemical and molecular events occurring during gamete activation. Glycolysis and mitochondrial oxidative phosphorylation (OXPHOS) are the two major metabolic pathways producing ATP which is the primary source of energy for spermatozoa. Since recent data suggest that spermatozoa have the ability to use different metabolic substrates, the main aim of this work is to present a broad overview of the current knowledge on the energy-producing metabolic pathways operating inside sperm mitochondria during capacitation in different mammalian species. Metabolism of glucose and of other energetic substrates, such as pyruvate, lactate, and citrate, is critically analyzed. Such knowledge, besides its obvious importance for basic science, could eventually translate into the development of novel strategies for treatment of male infertility, artificial reproduction, and sperm selection methods. PMID:24791005
Thompson, K A; Richa, J; Liebhaber, S A; Storey, B T
Mouse sperm cryopreservation provides a means for storing the genetic information in genetically modified mice (mutants, transgenics, and "knockouts") in a cost- and space-effective manner. Sperm from this species are highly sensitive to cryodamage, which has impeded their cryopreservation in the past. The cryoprotectant used in this study was 6% glycerol (0.65 M) plus 7.5% trehalose (0.22 M), which was added to a concentrated suspension of sperm from B6SJLF1/J mice in bicarbonate-free buffer by dialysis to minimize osmotic stress on the cells. Sperm suspensions were frozen in 0.25 mL straws and stored in liquid N2. Eggs were obtained from B6SJLF1/J superovulated females. For in vitro fertilization (IVF), 15-25 microL of sperm suspension post-thaw from one straw was added directly to each of three 1.5 mL drops of fertilization medium containing 30 eggs each, for 3 replicates per experiment. The fertilized eggs were scored for blastocyst formation, after which 12 blastocysts from each drop were implanted into pseudopregnant CD-1 females. The number of live pups were then scored at birth. Ten experiments yielded 21.7 +/- 1.4 (SD) blastocysts per 30 eggs inseminated (72%) and 7.3 +/- 0.4 (SD) live pups per 12 blastocysts implanted (61%). The overall yield of live pups was 44 per 100 eggs inseminated (44%). This yield should be satisfactory for maintaining a mouse strain through sperm cryostorage, with restart of the strain through IVF and embryo transfer. The method should also provide improvement in human sperm cryopreservation, as human sperm are less sensitive to cryodamage than are mouse sperm.
Losdat, Sylvain; Richner, Heinz; Blount, Jonathan D.; Helfenstein, Fabrice
Mounting an immune response against pathogens incurs costs to organisms by its effects on important life-history traits, such as reproductive investment and survival. As shown recently, immune activation produces large amounts of reactive species and is suggested to induce oxidative stress. Sperm are highly susceptible to oxidative stress, which can negatively impact sperm function and ultimately male fertilizing efficiency. Here we address the question as to whether mounting an immune response affects sperm quality through the damaging effects of oxidative stress. It has been demonstrated recently in birds that carotenoid-based ornaments can be reliable signals of a male's ability to protect sperm from oxidative damage. In a full-factorial design, we immune-challenged great tit males while simultaneously increasing their vitamin E availability, and assessed the effect on sperm quality and oxidative damage. We conducted this experiment in a natural population and tested the males' response to the experimental treatment in relation to their carotenoid-based breast coloration, a condition-dependent trait. Immune activation induced a steeper decline in sperm swimming velocity, thus highlighting the potential costs of an induced immune response on sperm competitive ability and fertilizing efficiency. We found sperm oxidative damage to be negatively correlated with sperm swimming velocity. However, blood resistance to a free-radical attack (a measure of somatic antioxidant capacity) as well as plasma and sperm levels of oxidative damage (lipid peroxidation) remained unaffected, thus suggesting that the observed effect did not arise through oxidative stress. Towards the end of their breeding cycle, swimming velocity of sperm of more intensely colored males was higher, which has important implications for the evolution of mate choice and multiple mating in females because females may accrue both direct and indirect benefits by mating with males having better quality sperm
OIKAWA, Toshinori; ITAHASHI, Tomoko; NUMABE, Takashi
The purpose of this study was to determine whether dithiothreitol (DTT) treatment of sperm and ethanol activation improve embryo production by intracytoplasmic sperm injection (ICSI). Further, we compared ICSI with standard in vitro fertilization (IVF) in oocytes obtained from cattle. We demonstrated that DTT reduced the disulfide bond in the bovine sperm head. Using oocytes obtained from a slaughterhouse, ICSI-DTT treatment without ethanol showed the highest rate of blastocyst formation. We applied these results to fertilization using ovum pick-up (OPU). Eleven Japanese black cattle served as donors for OPU plus standard IVF (OPU-IVF). Of them, four donors with low embryo development rates were selected to determine whether embryo development was enhanced by OPU plus ICSI (OPU-ICSI). We assessed effects on embryo development following IVF and ICSI in oocytes obtained using OPU. Blastocyst rates were significantly higher for OPU-ICSI than for OPU-IVF. Our results suggest that OPU-ICSI improves the blastocyst development rate in donors with low embryo production compared with the standard OPU-IVF. PMID:26460690
Oikawa, Toshinori; Itahashi, Tomoko; Numabe, Takashi
The purpose of this study was to determine whether dithiothreitol (DTT) treatment of sperm and ethanol activation improve embryo production by intracytoplasmic sperm injection (ICSI). Further, we compared ICSI with standard in vitro fertilization (IVF) in oocytes obtained from cattle. We demonstrated that DTT reduced the disulfide bond in the bovine sperm head. Using oocytes obtained from a slaughterhouse, ICSI-DTT treatment without ethanol showed the highest rate of blastocyst formation. We applied these results to fertilization using ovum pick-up (OPU). Eleven Japanese black cattle served as donors for OPU plus standard IVF (OPU-IVF). Of them, four donors with low embryo development rates were selected to determine whether embryo development was enhanced by OPU plus ICSI (OPU-ICSI). We assessed effects on embryo development following IVF and ICSI in oocytes obtained using OPU. Blastocyst rates were significantly higher for OPU-ICSI than for OPU-IVF. Our results suggest that OPU-ICSI improves the blastocyst development rate in donors with low embryo production compared with the standard OPU-IVF.
Theodoridou, Maria; Nomikos, Michail; Parthimos, Dimitris; Gonzalez-Garcia, J. Raul; Elgmati, Khalil; Calver, Brian L.; Sideratou, Zili; Nounesis, George; Swann, Karl; Lai, F. Anthony
Phospholipase C-zeta (PLCζ) is a sperm-specific protein believed to cause Ca2+ oscillations and egg activation during mammalian fertilization. PLCζ is very similar to the somatic PLCδ1 isoform but is far more potent in mobilizing Ca2+ in eggs. To investigate how discrete protein domains contribute to Ca2+ release, we assessed the function of a series of PLCζ/PLCδ1 chimeras. We examined their ability to cause Ca2+ oscillations in mouse eggs, enzymatic properties using in vitro phosphatidylinositol 4,5-bisphosphate (PIP2) hydrolysis and their binding to PIP2 and PI(3)P with a liposome interaction assay. Most chimeras hydrolyzed PIP2 with no major differences in Ca2+ sensitivity and enzyme kinetics. Insertion of a PH domain or replacement of the PLCζ EF hands domain had no deleterious effect on Ca2+ oscillations. In contrast, replacement of either XY-linker or C2 domain of PLCζ completely abolished Ca2+ releasing activity. Notably, chimeras containing the PLCζ XY-linker bound to PIP2-containing liposomes, while chimeras containing the PLCζ C2 domain exhibited PI(3)P binding. Our data suggest that the EF hands are not solely responsible for the nanomolar Ca2+ sensitivity of PLCζ and that membrane PIP2 binding involves the C2 domain and XY-linker of PLCζ. To investigate the relationship between PLC enzymatic properties and Ca2+ oscillations in eggs, we have developed a mathematical model that incorporates Ca2+-dependent InsP3 generation by the PLC chimeras and their levels of intracellular expression. These numerical simulations can for the first time predict the empirical variability in onset and frequency of Ca2+ oscillatory activity associated with specific PLC variants. PMID:24152875
Ebchuqin, Eerdundagula; Yokota, Naoto; Yamada, Lixy; Yasuoka, Yuuri; Akasaka, Mari; Arakawa, Mio; Deguchi, Ryusaku; Mori, Toshiyuki; Sawada, Hitoshi
It has been reported that GCS1 (Generative Cell Specific 1) is a transmembrane protein that is exclusively expressed in sperm cells and is essential for gamete fusion in flowering plants. The GCS1 gene is present not only in angiosperms but also in unicellular organisms and animals, implying the occurrence of a common or ancestral mechanism of GCS1-mediated gamete fusion. In order to elucidate the common mechanism, we investigated the role of GCS1 in animal fertilization using a sea anemone (Cnidaria), Nematostella vectensis. Although the existence of the GCS1 gene in N. vectensis has been reported, the expression of GCS1 in sperm and the role of GCS1 in fertilization are not known. In this study, we showed that the GCS1 gene is expressed in the testis and that GCS1 protein exists in sperm by in situ hybridization and proteomic analysis, respectively. Then we made four peptide antibodies against the N-terminal extracellular region of NvGCS1. These antibodies specifically reacted to NvGCS1 among sperm proteins on the basis of Western analysis and potently inhibited fertilization in a concentration-dependent manner. These results indicate that sperm GCS1 plays a pivotal role in fertilization, most probably in sperm-egg fusion, in a starlet sea anemone, suggesting a common gamete-fusion mechanism shared by eukaryotic organisms.
Berlinguer, Fiammetta; Ledda, Sergio; Rosati, Irma; Bogliolo, Luisa; Leoni, Giovanni; Naitana, Salvatore
This study evaluated the effects of superoxide dismutase (SOD) on viability and acrosome integrity of European mouflon spermatozoa after cryopreservation and on the fertilization rates of sheep oocytes after i.v.f. or intracytoplasmatic sperm injection (i.c.s.i.). Frozen semen was thawed and washed with synthetic oviduct fluid supplemented with 0.6% bovine serum albumin. After centrifugation, the spermatozoa pellet was split into two culture systems: (i) without SOD; and (ii) in the presence of 1500 IU mL(-1) SOD. Sperm viability and acrosome integrity were evaluated simultaneously, immediately after thawing and after 3, 6 and 9 h of culture (5% CO2, 39 degrees C, 90% humidity), by incubating sperm with propidium iodide and fluorescein isothiocyanate-labelled Pisum sativum agglutinin. At the same time, sperm were assessed for motility using a standard scoring system (independent operators' observation of sperm) that graded degree of motility (i.e. 1 = immotile to 10 = maximum motility, as observed at the moment of thawing). For i.v.f., frozen-thawed semen derived from the two culture systems was placed in culture together with in vitro-matured sheep oocytes. For i.c.s.i., semen derived from the same culture systems as that for i.v.f. was used, and incubated for 1 h under standard conditions. The results showed a marked difference (P < 0.01) between the percentages of live spermatozoa in medium with SOD and those obtained in medium alone, after 3, 6 and 9 h of culture. The percentages of intact acrosome spermatozoa were higher in medium with SOD after 6 h (P = 0.05) of culture. Spermatozoa motility decreased significantly in SOD containing medium at 3 and 6 h of culture compared with motility in control medium. Fertilization rates were significantly lower in medium with SOD than in medium alone, whereas in the i.c.s.i. system fertilization rates were significantly higher in the presence of SOD. The results indicate that the addition of SOD to the culture media
Nakai, Michiko; Ito, Junya; Sato, Ken-Ichi; Noguchi, Junko; Kaneko, Hiroyuki; Kashiwazaki, Naomi; Kikuchi, Kazuhiro
In pigs, although ICSI is a feasible fertilization technique, its efficiency is low. In general, injected pig sperm are insufficient to induce oocyte activation and embryonic development. Pretreatments for disrupting sperm membranes have been applied to improve the fertility of ICSI oocytes; however, we hypothesize that such pretreatment(s) may reduce the ability of the sperm to induce oocyte activation. We first evaluated the effects of sperm pretreatments (sonication (SO) to isolate the sperm heads from the tails, Triton X-100 (TX), and three cycles of repeated freezing/thawing (3×-FT) for disrupting sperm membranes) on the rate of pronucleus (PN) formation after ICSI. We found that oocytes injected with control (whole) sperm had higher rates of PN formation than those obtained after subjecting the sperm to SO, TX, and 3×-FT. The amounts of phospholipase Cζ (PLCζ), which is thought to be the oocyte-activating factor in mammalian sperm, in sperm treated by each method was significantly lower than that in whole untreated sperm. Furthermore, using immunofluorescence, it was found that in pig sperm, PLCζ was localized to both the post-acrosomal region and the tail area. Thus we demonstrated for the first time that sperm pretreatment leads to a reduction of oocyte-activating capacity. Our data also show that in addition to its expected localization to the sperm head, PLCζ is also localized in the tail of pig sperm, thus raising the possibility that injection of whole sperm may be required to attain successful activation in pigs.
SINKEWICZ, MARILYN; GARFINKEL, IRWIN
We present new estimates of unwed fathers’ ability to pay child support. Prior research relied on surveys that drastically undercounted nonresident unwed fathers and provided no link to their children who lived in separate households. To overcome these limitations, previous research assumed assortative mating and that each mother partnered with one father who was actually eligible to pay support and had no other child support obligations. Because the Fragile Families and Child Wellbeing Study contains data on couples, multiple-partner fertility, and a rich array of other previously unmeasured characteristics of fathers, it is uniquely suited to address the limitations of previous research. We also use an improved method of dealing with missing data. Our findings suggest that previous research overestimated the aggregate ability of unwed nonresident fathers to pay child support by 33% to 60%. PMID:21305392
Zou, Hong-tao; Ling, Yao; Yu, Yang; Zhang, Yu-ling; Yu, Na; Zhang, Yu-long
Using outdoor exposure and cinnamon soil incubation test, by quality changes, infrared spectroscopy and electron microscopic scanning technology, to research the degradation ability of self-developed coated fertilizer films. The results of outdoor exposure and cinnamon soil incubation test showed that all films had certain degradation ability, and the degradation rate increased with the increase of time. Under two kinds of test conditions, the highest degradation rate could reach above 35%. The degradation ability of film citric acid/ PVA was much stronger than epoxy resin/PVA. The degradation ability of citric acid/PVA/diatomite composite film materials was further enhanced because of the addition of diatomite. The epoxy resin/PVA composite film materials, although they had certain degradability, compared to the contrast, the difference was not significant, and adding diatomite can't obviously increase the degradation rate. The results of IR spectroscopy showed that some major functional groups, such as C==O, C==C, ==C--H would be reduced after degradation, and the transmission rate also increased, which showed that the degradation of composite film materials must be happened Scanning electron microscopy showed that the surface becomes rough and uneven, and it also meant the films have some degradation. The results of IR spectroscopy and scanning electron microscopy were consistent with the results of quality change test, and could more objectively represent the degradability of film material. Modified film materials can effectively control nutrient release without causing harm to the soil environment, so it is suitable for the film materials of coated fertilizer.
Perteghella, Sara; Gaviraghi, Alessandro; Cenadelli, Silvia; Bornaghi, Valeria; Galli, Andrea; Crivelli, Barbara; Vigani, Barbara; Vigo, Daniele; Chlapanidas, Theodora; Faustini, Massimo; Torre, Maria Luisa
The use of artificial insemination (AI) in buffalo (Bubalus bubalis) is limited by poor ovarian activity during the hot season, seasonal qualitative patterns in semen, low resistance of sperm cells in the female tract, difficulties in estrus detection, and variable estrus duration. Although AI procedures are commonly used in bovine, use of AI has been limited in buffalo. In the zootechnical field, different studies have been conducted to develop techniques for improvement of fertilizing ability of buffalo spermatozoa after AI. In this study, for the first time, the use of alginate encapsulation and cryopreservation of buffalo spermatozoa is described, and the same procedure was performed with Holstein Friesian (Bos taurus) semen. Results obtained from in vitro analyses indicate that the encapsulation process does not have detrimental effects (compared to controls) on quality parameters (membrane integrity, progressive motility, path average velocity) in either species. Similarly, there were no detrimental effects after cryopreservation in either species. The fertilizing potential of encapsulated and cryopreserved semen was evaluated after AI in 25 buffalo and 113 bovine females. Pregnancy rates were not affected in either species. The results of this study show proof of concept for the use of frozen semen controlled-release devices in buffalo.
Perteghella, Sara; Gaviraghi, Alessandro; Cenadelli, Silvia; Bornaghi, Valeria; Galli, Andrea; Crivelli, Barbara; Vigani, Barbara; Vigo, Daniele; Faustini, Massimo; Torre, Maria Luisa
The use of artificial insemination (AI) in buffalo (Bubalus bubalis) is limited by poor ovarian activity during the hot season, seasonal qualitative patterns in semen, low resistance of sperm cells in the female tract, difficulties in estrus detection, and variable estrus duration. Although AI procedures are commonly used in bovine, use of AI has been limited in buffalo. In the zootechnical field, different studies have been conducted to develop techniques for improvement of fertilizing ability of buffalo spermatozoa after AI. In this study, for the first time, the use of alginate encapsulation and cryopreservation of buffalo spermatozoa is described, and the same procedure was performed with Holstein Friesian (Bos taurus) semen. Results obtained from in vitro analyses indicate that the encapsulation process does not have detrimental effects (compared to controls) on quality parameters (membrane integrity, progressive motility, path average velocity) in either species. Similarly, there were no detrimental effects after cryopreservation in either species. The fertilizing potential of encapsulated and cryopreserved semen was evaluated after AI in 25 buffalo and 113 bovine females. Pregnancy rates were not affected in either species. The results of this study show proof of concept for the use of frozen semen controlled-release devices in buffalo. PMID:27456772
Fitzpatrick, John L; Lüpold, Stefan
Sperm experience intense and varied selection that dramatically impacts the evolution of sperm quality. Selection acts to ensure that sperm are fertilization-competent and able to overcome the many challenges experienced on their way towards eggs. However, simply being able to fertilize an egg is not enough to ensure male fertility in most species. Owing to the prevalence of female multiple mating throughout the animal kingdom, successful fertilization requires sperm to outcompete rival sperm. In addition, females can actively influence sperm quality, storage or utilization to influence male fertility. This review provides an overview of how these selective forces influence the evolution of sperm quality. After exploring the link between sperm traits and male fertility, we examine how post-mating competition between rival ejaculates influences the evolution of sperm quality. We then describe how complex genetic, social and sexual interactions influence sperm quality, focusing on the importance of seminal fluid and interactions between sperm and the female's reproductive tract. In light of the complexities of selection on sperm traits, greater use of multivariate approaches that incorporate male-male, sperm-sperm and sperm-female interactions to study sperm quality will enhance our understanding of how selection acts on sperm traits and factors influencing male fertility. Because the metric of male reproductive success--fertilization--is the same across the animal kingdom, we argue that information about sperm evolution gained from non-human animals has enormous potential to further our understanding of the factors that impact human fertility.
Ping, S; Wang, F; Zhang, Y; Wu, C; Tang, W; Luo, Y; Yang, S
Cryopreservation of sperm from tree shrews, which are considered primitive primates, would enhance genetic management and breeding programs. Epididymal sperm were surgically harvested from male tree shrews, cryopreserved in two Tes-Tris-based cryodiluents, and used in four experiments. In Experiment 1, there were no significant differences in motility and acrosome integrity among five concentrations of egg yolk in TTE after cooling to 4 °C. However, sperm frozen in TTE containing 20% egg yolk at -172 °C/min had better (P < 0.05) post-thaw motility and acrosome integrity. In Experiment 2, sperm held for 10 min prior to storage in liquid nitrogen had greater motility than those held for 5 or 15 min (P < 0.05), but acrosome integrity was not different (P > 0.05) among treatments. In Experiment 3, sperm frozen in TTE diluent had higher (P < 0.05) motility and acrosome integrity than those in TEST diluent. In Experiment 4, there were no differences (P > 0.05) in the fertilization rate of oocytes and the proportion of tree shrews yielding fertilized oocytes, following AI with fresh versus frozen sperm. In conclusion, tree shrew epididymal sperm were successfully cryopreserved, as assessed by post-thaw motility, acrosome integrity, and fertilizing ability.
Luna, C; Colás, C; Casao, A; Serrano, E; Domingo, J; Pérez-Pé, R; Cebrián-Pérez, J A; Muiño-Blanco, T
Incubation of ram spermatozoa in capacitating conditions with cAMP-elevating agents promotes a progressive time-dependent increase in the capacitated sperm subpopulation. In this study, the fertilizing capacity of ram spermatozoa (ability to bind to the zona pellucida, ZBA rate) capacitated in these conditions was determined. The results showed an increase (P < 0.001) in ZBA rate related to control samples in basal medium that contained BSA, calcium, and bicarbonate (1.97 ± 0.19 vs. 1.31 ± 0.09 sperm bound/oocyte, respectively). A significant correlation between protein tyrosine phosphorylation and ZBA rate (P < 0.05, r = 0.501) corroborated that incubation in a "high-cAMP" environment improves the fertilizing ability of ram spermatozoa. Likewise, the presence of two seminal plasma (SP) proteins able to protect sperm against cold shock (RSVP14 and RSVP20) was evidenced in both SP and the ram sperm surface, and their influence in the fertilizing ability of spermatozoa capacitated in basal medium or with cAMP-elevating agents was determined. The results verified that RSVP14 and RSVP20 act as decapacitating factors given that their addition to SP-free sperm samples previously to capacitation maintained high proportions of the noncapacitated sperm pattern with no increase in protein tyrosine phosphorylation. However, the obtained ZBA rate in the high-cAMP-containing samples was increased in the presence of RSVP20 (P < 0.05). These findings would indicate that the stimulating effect exerted by this protein on the sperm-oocyte binding occurs downstream from the cAMP generation and that the mechanisms by which RSVP20 promotes the zona pellucida binding might be independent of protein tyrosine phosphorylation.
Li, Jing; Pang, Shaojun; Liu, Feng; Shan, Tifeng; Gao, Suqin
During sexual reproduction of seaweeds, spermatozoid (sperm) discharge is triggered by chemical messengers (pheromones) released by the female gametes. The chemotactic ability of the sperm ensures fertilization success. Using unialgal male and female gametophyte material under designated standard gametogenesis testing (SGT) conditions, the potential life-span of the sperm of two seaweeds, Saccharina japonica and Undaria pinnatifida, was assessed by their ability to fertilize eggs. Results show that within 20-30 min after being discharged, sperm of both species could complete fertilization without an apparent decline in fertilization rate. Although fertilization rate 60-120 min after sperm discharge dropped significantly in both species, some sperm were viable enough to fertilize the eggs. In S. japonica, at 12°C, some sperm were able to fertilize eggs up to 12 h after discharge. In both species, egg discharge rates (EDR) in the male and female mixed positive controls were significantly higher than those of all the sperm-testing groups. Doubling the seeded male gametophytes of S. japonica in the SGT tests significantly increased the EDR, further confirming the effect of the presence of the male on the female in terms of facilitating egg discharge from oogonia.
Tordjman, K M; Yaron, M; Berkovitz, A; Botchan, A; Sultan, C; Lumbroso, S
We report on a case of a man with familial, X-linked, partial androgen insensitivity, in whom a new point mutation in the androgen receptor (AR) ligand-binding domain (causing a valine-to-alanine substitution at codon 686) was identified. High-dose prolonged testosterone therapy resulted in marked progression in patient's appearance and great improvement in sperm count and characteristics. In combination with intracytoplasmic microinjection, treatment resulted in fertility. This is believed to be the first report of such a case. This case supports high-dose testosterone therapeutic trial in this condition. Furthermore, it underscores the possibility of achieving fertility with current endocrine and assisted reproduction modalities, making some of these X-linked AR mutations paternally transmissible.
Dowling, D K; Nowostawski, A Larkeson; Arnqvist, G
Sperm competition theory predicts that sperm traits influencing male fertilizing ability will evolve adaptively. However, it has been suggested that some sperm traits may be at least partly encoded by mitochondrial genes. If true, this may constrain the adaptive evolution of such traits because mitochondrial DNA (mtDNA) is maternally inherited and there is thus no selection on mtDNA in males. Phenotypic variation in such traits may nevertheless be high because mutations in mtDNA that have deleterious effects on male traits, but neutral or beneficial effects in females, may be maintained by random processes or selection in females. We used backcrossing to create introgression lines of seed beetles (Callosobruchus maculatus), carrying orthogonal combinations of distinct lineages of cytoplasmic and nuclear genes, and then assayed sperm viability and sperm length in all lines. We found sizeable cytoplasmic effects on both sperm traits and our analyses also suggested that the cytoplasmic effects varied across nuclear genetic backgrounds. We discuss some potential implications of these findings for sperm competition theory.
Tian, Yongsheng; Chen, Zhangfan; Tang, Jiang; Duan, Huimin; Zhai, Jieming; Li, Bo; Ma, Wenhui; Liu, Jiangchun; Hou, Yunxia; Sun, Zhengxiang
Fish embryo cryopreservation is highly important for the long-term preservation of genomic and genetic information; however, few successful cases of fish embryo cryopreservation have been reported over the past 60 years. This is the first study to use Epinephelus moara embryos from fertilization with cryopreserved sperm as experimental material. Embryos that developed to the 16-22 somite stage and tail-bud stage were treated with the vitrification solution PMG3T according to a five-step equilibration method and cryopreserved at various temperatures and storage duration. Only 19.9 ± 9.2% of 16-22 somite stage embryos and 1.3 ± 1.1% of tail-bud stage embryos survived when cooled at 4 °C for 60 min. In total, 8.0 ± 3.0% of 16-22 somite stage embryos survived when cooled at -25.7 °C for 30 min, 22.4 ± 4.7% of tail-bud stage embryos survived after 45 min of cooling at -25.7 °C, and none survived after 60 min. Only 2.0 ± 2.7% of embryos survived when cryopreserved at -140 °C for 20 min. However, 9.7% of tail-bud stage embryos survived after cryopreservation in liquid nitrogen (-196 °C) for 2 h. Most surviving embryos developed normally. Embryonic volume decreased and spherical segments appeared when embryos were treated with higher concentrations of vitrification solution. Additionally, the volume recovered gradually after rinsing with sucrose and seawater. This is the first estimate of the survival of E. moara embryos and larvae after cryopreservation. These findings provide a foundation for further explorations of fish embryo cryopreservation techniques.
Clark, A.G.; Prout, T.; Harshman, L.G.
Genes that influence mating and/or fertilization success may be targets for strong natural selection. If females remate frequently relative to the duration of sperm storage and rate of sperm use, sperm displacement may be an important component of male reproductive success. Although it has long been known that mutant laboratory stocks of Drosophila differ in sperm displacement, the magnitude of the naturally occurring genetic variation in this character has not been systematically quantified. Here we report the results of a screen for variation in sperm displacement among 152 lines of Drosophila melanogaster that were made homozygous for second and/or third chromosomes recovered from natural populations. Sperm displacement was assayed by scoring the progeny of cn;bw females that had been mated sequentially to cn;bw and tested males in either order. Highly significant differences were seen in both the ability to displace sperm that is resident in the female`s reproductive tract and in the ability to resist displacement by subsequent sperm. Most lines exhibited nearly complete displacement, having nearly all progeny sired by the second male, but several lines had as few as half the progeny fathered by the second male. Lines that were identified in the screen for naturally occurring variation in sperm displacement were also characterized for single-strand conformation polymorphisms (SSCP) at seven accessory gland protein (Acp) genes. Significant associations were found between particular Acp alleles at four different loci (Acp26Aa/Ab, Acp29B, Acp36DE and Acp53E) and the ability of males to resist displacement by subsequent sperm. There was no correlation between the ability to displace resident sperm and the ability to resist being displaced by subsequent sperm. This lack of correlation, and the association of Acp alleles with resisting subsequent sperm only, suggests that different mechanisms mediate the two components of sperm displacement. 36 refs., 4 figs., 7 tabs.
Lin, Chien-Yu; Chen, Chun-Yu; Yu, Chih-Hsiang; Yu, I-Shing; Lin, Shu-Rung; Wu, June-Tai; Lin, Ying-Hung; Kuo, Pao-Lin; Wu, Jui-Ching; Lin, Shu-Wha
In this study, we demonstrate that an E3-ubiquitin ligase associated with human X-linked intellectual disability, CUL4B, plays a crucial role in post-meiotic sperm development. Initially, Cul4bΔ/Y male mice were found to be sterile and exhibited a progressive loss in germ cells, thereby leading to oligoasthenospermia. Adult Cul4b mutant epididymides also contained very low numbers of mature spermatozoa, and these spermatazoa exhibited pronounced morphological abnormalities. In post-meiotic spermatids, CUL4B was dynamically expressed and mitosis of spermatogonia and meiosis of spermatocytes both appeared unaffected. However, the spermatids exhibited significantly higher levels of apoptosis during spermiogenesis, particularly during the acrosome phase through the cap phase. Comparative proteomic analyses identified a large-scale shift between wild-type and Cul4b mutant testes during early post-meiotic sperm development. Ultrastructural pathology studies further detected aberrant acrosomes in spermatids and nuclear morphology. The protein levels of both canonical and non-canonical histones were also affected in an early spermatid stage in the absence of Cul4b. Thus, X-linked CUL4B appears to play a critical role in acrosomal formation, nuclear condensation, and in regulating histone dynamics during haploid male germ cell differentiation in relation to male fertility in mice. Thus, it is possible that CUL4B-selective substrates are required for post-meiotic sperm morphogenesis. PMID:26832838
Lin, Chien-Yu; Chen, Chun-Yu; Yu, Chih-Hsiang; Yu, I-Shing; Lin, Shu-Rung; Wu, June-Tai; Lin, Ying-Hung; Kuo, Pao-Lin; Wu, Jui-Ching; Lin, Shu-Wha
In this study, we demonstrate that an E3-ubiquitin ligase associated with human X-linked intellectual disability, CUL4B, plays a crucial role in post-meiotic sperm development. Initially, Cul4b(Δ)/Y male mice were found to be sterile and exhibited a progressive loss in germ cells, thereby leading to oligoasthenospermia. Adult Cul4b mutant epididymides also contained very low numbers of mature spermatozoa, and these spermatazoa exhibited pronounced morphological abnormalities. In post-meiotic spermatids, CUL4B was dynamically expressed and mitosis of spermatogonia and meiosis of spermatocytes both appeared unaffected. However, the spermatids exhibited significantly higher levels of apoptosis during spermiogenesis, particularly during the acrosome phase through the cap phase. Comparative proteomic analyses identified a large-scale shift between wild-type and Cul4b mutant testes during early post-meiotic sperm development. Ultrastructural pathology studies further detected aberrant acrosomes in spermatids and nuclear morphology. The protein levels of both canonical and non-canonical histones were also affected in an early spermatid stage in the absence of Cul4b. Thus, X-linked CUL4B appears to play a critical role in acrosomal formation, nuclear condensation, and in regulating histone dynamics during haploid male germ cell differentiation in relation to male fertility in mice. Thus, it is possible that CUL4B-selective substrates are required for post-meiotic sperm morphogenesis.
Capacitation is a series of morphological and metabolic changes necessary for the spermatozoon to achieve fertilizing ability. One of the earlier happenings during mammalian sperm capacitation is the production of reactive oxygen species (ROS) that will trigger and regulate a series of events including protein phosphorylation, in a time-dependent fashion. The identity of the sperm oxidase responsible for the production of ROS involved in capacitation is still elusive, and several candidates are discussed in this review. Interestingly, ROS-induced ROS formation has been described during human sperm capacitation. Redox signaling during capacitation is associated with changes in thiol groups of proteins located on the plasma membrane and subcellular compartments of the spermatozoon. Both, oxidation of thiols forming disulfide bridges and the increase on thiol content are necessary to regulate different sperm proteins associated with capacitation. Reducing equivalents such as NADH and NADPH are necessary to support capacitation in many species including humans. Lactate dehydrogenase, glucose-6-phospohate dehydrogenase, and isocitrate dehydrogenase are responsible in supplying NAD (P) H for sperm capacitation. Peroxiredoxins (PRDXs) are newly described enzymes with antioxidant properties that can protect mammalian spermatozoa; however, they are also candidates for assuring the regulation of redox signaling required for sperm capacitation. The dysregulation of PRDXs and of enzymes needed for their reactivation such as thioredoxin/thioredoxin reductase system and glutathione-S-transferases impairs sperm motility, capacitation, and promotes DNA damage in spermatozoa leading to male infertility. PMID:25926608
Kadirvel, Govindasamy; Machado, Sergio A.; Korneli, Claudia; Collins, Emily; Miller, Paul; Bess, Kelsey N.; Aoki, Kazuhiro; Tiemeyer, Michael; Bovin, Nicolai; Miller, David J.
ABSTRACT After mating, many female mammals store a subpopulation of sperm in the lower portion of the oviduct, forming a reservoir. The reservoir lengthens sperm lifespan, regulates sperm capacitation, controls polyspermy, and selects normal sperm. It is believed that sperm bind to glycans on the oviduct epithelium to form the reservoir, but the specific adhesion molecules that retain sperm are unclear. Herein, using a glycan array to test 377 glycans for their ability to bind porcine sperm, we found two glycan motifs in common among all glycans with sperm-binding ability: the Lewis X trisaccharide and biantennary structures containing a mannose core with 6-sialylated lactosamine at one or more termini. Binding to both motifs was specific; isomers of each motif did not bind sperm. Further work focused on sialylated lactosamine. Sialylated lactosamine was found abundantly on the apical side of epithelial cells collected from the oviduct isthmus, among N-linked and O-linked glycans. Sialylated lactosamine bound to the head of sperm, the region that interacts with the oviduct epithelium. After capacitation, sperm lost affinity for sialylated lactosamine. Receptor modification may contribute to release from the reservoir so that sperm can move to the site of fertilization. Sialylated lactosamine was required for sperm to bind oviduct cells. Simbucus nigra agglutinin or an antibody specific to sialylated lactosamine with a preference for Neu5Acalpha2-6Gal rather than Neu5Acalpha2-3Gal reduced sperm binding to oviduct isthmic cells, as did occupying putative receptors on sperm with sialylated biantennary glycans. These results demonstrate that sperm binding to oviduct 6-sialylated biantennary glycans is necessary for normal adhesion to the oviduct. PMID:23115267
Abu Hassan Abu, D; Franken, D R; Hoffman, B; Henkel, R
Sperm morphology has been associated with in vitro as well as in vivo fertilisation. The study aimed to evaluate the possible relation between the percentage of spermatozoa with normal morphology and the following sperm functional assays: (i) zona-induced acrosome reaction (ZIAR); (ii) DNA integrity; (iii) chromatin condensation; (iv) sperm apoptosis; and (v) fertilisation rates. Regression analysis was employed to calculate the association between morphology and different functional tests. Normal sperm morphology correlated significantly with the percentages of live acrosome-reacted spermatozoa in the ZIAR (r = 0.518; P < 0.0001; n = 92), DNA integrity (r = -0.515; P = 0.0018; n = 34), CMA(3) -positive spermatozoa (r = -0.745; P < 0.0001; n = 92), sperm apoptosis (r = -0.395; P = 0.0206; n = 34) and necrosis (r = -0.545; P = 0.0009; n = 34). Negative correlations existed between for the acrosome reaction, and DNA integrity, while negative associations were recorded with the percentages of CMA(3) -positive spermatozoa, apoptotic and necrotic spermatozoa. Sperm morphology is related to sperm dysfunction such as poor chromatin condensation, acrosome reaction and DNA integrity. Negative and significant correlations existed between normal sperm morphology and chromatin condensation, the percentage of spermatozoa with abnormal DNA and spermatozoa with apoptotic activity. The authors do not regard sperm morphology as the only test for the diagnosis of male fertility, but sperm morphology can serve as a valuable indicator of underlying dysfunction.
Abaigar, Teresa; Barbero, Javier; Holt, William V
The objectives of the present study were to develop an alternative theoretical approach to the analysis of sperm motility and to develop motility parameters that would complement those more commonly used in current computer-assisted semen analysis procedures. We have defined a set of parameters and have tested them using boar spermatozoa undergoing bicarbonate-induced motility activation. The new parameters were calculated for a series of (x,y) coordinates of sperm head positions recorded at each move along the trajectory. The parameters were: mean velocity (MV), immobility ratio, fractal dimension (FD), the variance of the steplengths (VAR), and 2 autocorrelation function coefficients of the step-length time series for lags 1 and 2 (C(1) and C(2)). MV measures the average speed along the trajectory, and VAR is a measure of displacement variability that can be related to the specific mean (per step) kinetic energy of the spermatozoon. All of the parameters except MV and FD were affected by the sampling frequency (25 vs 50 Hz); inappropriately high sampling frequency in relation to magnification resulted in step-lengths between successive frames that were below the resolution threshold of the imaging system. The autocorrelation functions were especially informative; discrimination between sperm subpopulations was obvious within simple histogram formats, and complex statistical analyses were not needed for their identification.
Crichton, Elizabeth G; Malo, Clara; Pukazhenthi, Budhan S; Nagy, Peter; Skidmore, Julian A
Cholesterol (cholesterol-loaded cyclodextrins: CLC) treatment of dromedary camel sperm prior to freezing enhances cryosurvival. The present study first validated the efficacy of a heterologous zona-free goat oocyte assay (n=115 oocytes) to evaluate camel sperm function in vitro (Experiment 1: n=6 bulls), then examined the effects of CLC treatment (1.5mg/mL CLC; CLC+) versus no treatment (0 CLC) of fresh (Experiment 2: n=4 bulls) and frozen-thawed (Experiment 3: n=5 bulls) camel sperm to penetrate, de-condense and form pro-nuclei in in vitro-matured goat oocytes. Finally, the ability of fresh 0 CLC and CLC+ sperm to fertilize in vivo was studied by artificially inseminating super-ovulated females (n=7-9 per treatment) and examining embryo production (Experiment 4: n=4-5 bulls/treatment). Camel spermatozoa penetrated (60%) and formed pro-nuclei (33%) in goat oocytes demonstrating the utility of this heterologous system for assessing sperm function in vitro. For fresh spermatozoa, 0 CLC-treated sperm performed better than their CLC+ counterparts for all parameters measured (P<0.05). In contrast, cryopreservation resulted in a sharp decline in sperm-oocyte interaction in 0 CLC aliquots but remained unaltered in CLC+ aliquots demonstrating a protective effect of cholesterol treatment. There was no difference between treatments in the in vitro fertilizing ability of frozen-thawed sperm or in the numbers of embryos retrieved following AI with fresh 0 CLC or CLC+ sperm. We conclude that although CLC treatment of dromedary camel sperm improves sperm motility it fails to confer an advantage to them in terms of improved in vitro sperm-oocyte interaction or in vivo fertilization under the conditions tested.
Yamauchi, Yasuhiro; Riel, Jonathan M.; Ruthig, Victor; Ward, Monika A.
Abstract Spermatogenesis is a key developmental process allowing for a formation of a mature male gamete. During its final phase, spermiogenesis, haploid round spermatids undergo cellular differentiation into spermatozoa, which involves extensive restructuring of cell morphology, DNA, and epigenome. Using mouse models with abrogated Y chromosome gene complements and Y-derived transgene we identified Y chromosome encoded Zfy2 as the gene responsible for sperm formation and function. In the presence of a Zfy2 transgene, mice lacking the Y chromosome and transgenic for two other Y-derived genes, Sry driving sex determination and Eif2s3y initiating spermatogenesis, are capable of producing sperm which when injected into the oocytes yield live offspring. Therefore, only three Y chromosome genes, Sry, Eif2s3y and Zfy2, constitute the minimum Y chromosome complement compatible with successful intracytoplasmic sperm injection in the mouse. PMID:26719889
Mattheus, A; Heise, H; Hofmann, R
The effect of different Solcoseryl (Solco, Basel, Switzerland) concentrations on the motility of human sperm were tested on 37 ejaculates taken from two subject groups. Altogether 111 motility studies were performed using the eosine vitality test. In view of the considerable variations associated with motility tests, Solcoseryl appeared to have no effect on sperm motility in the majority of cases in group 1. The observed improvement in motility (20%) was countered by still greater motility losses (27%). The results, obtained by studies on selected asthenospermia (group 2) are different, however: the 26% increase in motility was opposed to a motility loss of only 17%. A Solcoseryl concentration of 50% was found to have the best effects on motility. A general rise in sperm motility by means of Solcoseryl cannot be considered, although tests would appear advisable in isolated instances. Solcoseryl may be a valuable protective resuspension agent for insemination purposes.
Misra, Snigdha; Kumar, Ajay; Ratnasekhar, Ch.; Sharma, Vandana; Mudiam, Mohana Krishna Reddy; Ram, Kristipati Ravi
Dwindling male fertility due to xenobiotics is of global concern. Accordingly, male reproductive toxicity assessment of xenobiotics through semen quality analysis in exposed males, and examining progeny production of their mates is critical. These assays, in part, are biased towards monogamy. Females soliciting multiple male partners (polyandry) is the norm in many species. Polyandry incites sperm competition and allows females to bias sperm use. However, consequences of xenobiotic exposure to the sperm in the light of sperm competition remain to be understood. Therefore, we exposed Drosophila melanogaster males to endosulfan, and evaluated their progeny production as well as the ability of their sperm to counter rival control sperm in the storage organs of females sequentially mated to control/exposed males. Endosulfan (2 μg/ml) had no significant effect on progeny production and on the expression of certain genes associated with reproduction. However, exposed males performed worse in sperm competition, both as 1st and 2nd male competitors. These findings indicate that simple non-competitive measures of reproductive ability may fail to demonstrate the harmful effects of low-level exposure to xenobiotics on reproduction and advocate consideration of sperm competition, as a parameter, in the reproductive toxicity assessment of xenobiotics to mimic situations prevailing in the nature. PMID:25503806
Li, Chun-Jin; Wang, Dong; Zhou, Xu
Sperm is highly differentiated cell that can be easily obtained and purified. Mature sperm is considered to be transcriptionally and translationally silent and incapable of protein synthesis. Recently, a large number of proteins have been identified in sperm from different species by using the proteomic approaches. Clinically, sperm proteins can be used as markers for male infertility due to different protein profiles identified in sperm from fertile and infertile male animals. Recent evidences have shown that the conditions of sperm preservation in vitro can also change the sperm protein profiles. This paper reviews the recent scientific publications available to address sperm proteome and their relationship with sperm cryopreservation, capacitation, fertilization, and separation of X and Y sperm. Future directions in the application of sperm proteomics to develop or optimize reproductive technologies in mammals are also discussed.
Moore-Ambriz, Teresita Rocio; Acuña-Hernández, Deyanira Guadalupe; Ramos-Robles, Brenda; Sánchez-Gutiérrez, Manuel; Santacruz-Márquez, Ramsés; Sierra-Santoyo, Adolfo; Piña-Guzmán, Belem; Shibayama, Mineko; Hernández-Ochoa, Isabel
Follicle growth culminates in ovulation, which allows for the expulsion of fertilizable oocytes and the formation of corpora lutea. Bisphenol A (BPA) is present in many consumer products, and it has been suggested that BPA impairs ovulation; however, the underlying mechanisms are unknown. Therefore, this study first evaluated whether BPA alters ovulation by affecting folliculogenesis, the number of corpora lutea or eggs shed to the oviduct, ovarian gonadotropin responsiveness, hormone levels, and estrous cyclicity. Because it has been suggested (but not directly confirmed) that BPA exerts toxic effects on the fertilization ability of oocytes, a second aim was to evaluate whether BPA impacts the oocyte fertilization rate using an in vitro fertilization assay and mating. The possible effects on early zygote development were also examined. Young adult female C57BL/6J mice (39 days old) were orally dosed with corn oil (vehicle) or 50 μg/kgbw/day BPA for a period encompassing the first three reproductive cycles (12-15 days). BPA exposure did not alter any parameters related to ovulation. Moreover, BPA exposure reduced the percentage of fertilized oocytes after either in vitro fertilization or mating, but it did not alter the zygotic stages. The data indicate that exposure to the reference dose of BPA does not impact ovulation but that it does influence the oocyte quality in terms of its fertilization ability.
Zheng, Jufeng; Lu, Yongning; Qu, Xianqin; Wang, Peng; Zhao, Luiwen; Gao, Minzhi; Shi, Huijuan; Jin, Xingliang
Introduction Spermatozoa motility is the critical parameter to affect the treatment outcomes during assisted reproductive technologies (ART), but its reproductive capability remains a little informed in condition of severe male factor infertility. This retrospective cohort study aimed to evaluate the effects of reduced sperm motility on the embryological and clinical outcomes in intra-cytoplasmic sperm injection (ICSI) treatment of severe oligozoospermia. Patients and Methods 966 cycles (812 couples) of severe oligozoospermia diagnosed by spermatozoa count ≤ 5 × 106/mL and motile spermatozoa ≤ 2 × 106/mL were divided into four groups in according to the number of motile spermatozoa in one ejaculate on the day of oocyte retrieval (Group B—E). The control (Group A) was 188 cycles of moderate oligozoospermia with spermatozoa count > 5 × 106/mL and motile spermatozoa > 2 × 106/mL. All female partners were younger than 35 years of age. Logistic regression analyzed embryological outcomes (the rates of fertilization, cleavage and good-quality embryo) and clinical outcomes (the rates of pregnancy, implantation, early miscarriage and live birth). Quality of embryo transfer (ET) was divided into three classes as continuous factor to test the effects of embryo quality on clinical outcomes. Results The reduction in the number of motile sperm in four groups of severe oligozoospermia gave rise to comparable inability of the fertilization (p < 0.001) and a decreased rate of good-quality embryo at Day 3 (p < 0.001) by compared to the control. The cleavage rate of the derived zygotes was similar to the control. ET classes significantly affected the clinical outcomes (p < 0.001). Class I ET gave rise to similar rates of clinical outcomes between five groups, but Class II and Class III ET retarded the rates of pregnancy, implantation and live birth and this particularly occurred in Group C, D and E. The rate of early miscarriage was not comparably different between groups
Chun, Sang Sik; Chung, Min Ji; Chong, Gun Oh; Park, Kee Sang; Lee, Taek Hoo
In this prospective clinical study involving 354 IVF-intracytoplasmic sperm injection cycles, we determined the influence of the length of the uterine cavity on clinical pregnancy rates. Our data showed that clinical pregnancy and implantation rates are associated positively with an increased length of the uterine cavity.
Gourounti, Kleanthi; Anagnostopoulos, Fotios; Vaslamatzis, Grigorios
A considerable literature has been accumulated regarding the relation of psychological factors to in-vitro fertilization outcome. However, study findings have been inconsistent, and the association between psychological stress and in-vitro fertilization outcomes is still unclear. The aim of the authors in this study was to examine the relation of infertility-related stress, anxiety, and depressive symptoms to in-vitro fertilization outcome. The sample consisted of 160 women with fertility problems undergoing fertility treatment in a public hospital in Athens, Greece between November 2008 and July 2009. The relation of infertility-related stress, anxiety, and depressive symptoms to in-vitro fertilization outcome was assessed by using hierarchical, sequential logistic regression, while controlling for the effects of relevant biomedical factors. After the embryo transfer, 41 women (26%) had a positive pregnancy outcome. Logistic regression analyses revealed that, controlling for biomedical factors (age, number of oocytes retrieved, and embryos transferred) infertility-specific stress (OR = 0.964, p = .011) and nonspecific anxiety (OR = 0.889, p = .006) were negatively associated with a positive pregnancy outcome after IVF. Psychological stress was negatively associated with in-vitro fertilization outcome, after controlling for biomedical variables. Fertility treatment protocols should consider including counselling interventions to potentially mitigate adverse effects of stress.
Ouchi, Kazuaki; Nishino, Atsuo; Nishida, Hiroki
The larvacean tunicate Oikopleura dioica is an attractive organism for studies of the development, evolution, and physiology of chordates, showing considerable promise for genetic approaches given its short life cycle of five days. To facilitate future genetic studies, the development of protocols for the maintenance of individual strains is essential. Here we report a simple and practical protocol for the cryopreservation of sperm using liquid nitrogen (-196°C) and dimethyl sulfoxide (DMSO) as a protective agent. The quality of the frozen-thawed sperm was evaluated in terms of fertilizing ability and subsequent development of the fertilized eggs. We examined several parameters to optimize the efficiency of cryopreservation, such as the concentration of DMSO, the method for acclimation of sperm to DMSO before freezing, and for placing sperm in liquid nitrogen, as well as the pH of the seawater used in resuspending the thawed sperm. We confirmed that viable sperm were recovered after preservation for more than one year. In addition, mature animals, and even a subsequent generation, were obtained from eggs fertilized by the cryopreserved sperm. The present procedure seems to be simple and sufficiently practical for maintenance of future established lines of O. dioica using frozen sperm.
Tung, Chih-kuan; Hu, Lian; Fiore, Alyssa G; Ardon, Florencia; Hickman, Dillon G; Gilbert, Robert O; Suarez, Susan S; Wu, Mingming
Successful mammalian reproduction requires that sperm migrate through a long and convoluted female reproductive tract before reaching oocytes. For many years, fertility studies have focused on biochemical and physiological requirements of sperm. Here we show that the biophysical environment of the female reproductive tract critically guides sperm migration, while at the same time preventing the invasion of sexually transmitted pathogens. Using a microfluidic model, we demonstrate that a gentle fluid flow and microgrooves, typically found in the female reproductive tract, synergistically facilitate bull sperm migration toward the site of fertilization. In contrast, a flagellated sexually transmitted bovine pathogen, Tritrichomonas foetus, is swept downstream under the same conditions. We attribute the differential ability of sperm and T. foetus to swim against flow to the distinct motility types of sperm and T. foetus; specifically, sperm swim using a posterior flagellum and are near-surface swimmers, whereas T. foetus swims primarily via three anterior flagella and demonstrates much lower attraction to surfaces. This work highlights the importance of biophysical cues within the female reproductive tract in the reproductive process and provides insight into coevolution of males and females to promote fertilization while suppressing infection. Furthermore, the results provide previously unidentified directions for the development of in vitro fertilization devices and contraceptives.
Tung, Chih-kuan; Hu, Lian; Fiore, Alyssa G.; Ardon, Florencia; Hickman, Dillon G.; Gilbert, Robert O.; Suarez, Susan S.; Wu, Mingming
Successful mammalian reproduction requires that sperm migrate through a long and convoluted female reproductive tract before reaching oocytes. For many years, fertility studies have focused on biochemical and physiological requirements of sperm. Here we show that the biophysical environment of the female reproductive tract critically guides sperm migration, while at the same time preventing the invasion of sexually transmitted pathogens. Using a microfluidic model, we demonstrate that a gentle fluid flow and microgrooves, typically found in the female reproductive tract, synergistically facilitate bull sperm migration toward the site of fertilization. In contrast, a flagellated sexually transmitted bovine pathogen, Tritrichomonas foetus, is swept downstream under the same conditions. We attribute the differential ability of sperm and T. foetus to swim against flow to the distinct motility types of sperm and T. foetus; specifically, sperm swim using a posterior flagellum and are near-surface swimmers, whereas T. foetus swims primarily via three anterior flagella and demonstrates much lower attraction to surfaces. This work highlights the importance of biophysical cues within the female reproductive tract in the reproductive process and provides insight into coevolution of males and females to promote fertilization while suppressing infection. Furthermore, the results provide previously unidentified directions for the development of in vitro fertilization devices and contraceptives. PMID:25870286
Cardoso, R C S; Silva, A R; Silva, L D M; Chirinéa, V H; Souza, F F; Lopes, M D
The aim of present study was to evaluate frozen canine semen with ACP-106 (Powder Coconut Water) using an in vitro sperm--oocyte interaction assay (SOIA). Ten ejaculates from five stud dogs were diluted in ACP-106 containing 20% egg yolk, submitted to cooling in a thermal box for 40 min and in a refrigerator for 30 min. After this period, a second dilution was performed using ACP-106 containing 20% egg yolk and 12% glycerol. Samples were thawed at 38 degrees C for 1 min. Post-thaw motility was evaluated by light microscopy and by using a computer aided semen analysis (CASA). Plasma membrane integrity and sperm morphology/acrosomal status were evaluated by fluorescent probes (C-FDA/PI) and Bengal Rose respectively. Moreover, frozen-thawed semen was analysed by a SOIA. Subjective post-thaw motility was 52.0 +/- 14.8% and it was significant higher than the total motility estimated by CASA (23.0 +/- 14.8%) because this system considered the egg yolk debris as immotile spermatozoa. Although normal sperm rate and acrosomal integrity evaluated by Bengal Rose stain was 89.6 +/- 3.1% and 94.3 +/- 3.1%, respectively, post-thaw percentage of intact plasma membrane was only 35.1 +/- 14.3%. Regarding SOIA, the percentage of interacted oocytes (bound, penetrated and bound and/or penetrated) was 75.3%. Using regression analysis, it was found significant relations between some CASA patterns and data for SOIA. In conclusion, the freezing-thawing procedure using ACP-106 was efficient for maintain the in vitro fertility potential of dog spermatozoa.
Selvaraju, Sellappan; Raju, Priyadarshini; Rao, Somu Bala Nageswara; Raghavendra, Subbarao; Nandi, Sumantha; Dineshkumar, Dhanasekaran; Thayakumar, Allen; Parthipan, Shivashanmugam; Ravindra, Janivara Parameswaraiah
The objective of the present study was to elucidate the effect of different sources of dietary energy (maize vs polyunsaturated fatty acid (PUFA) on semen functional parameters and fertility of adult rams. Eighteen adult rams were divided into two groups (maize and PUFA, n=9). The main energy source for the rams in the maize group was coarsely ground maize grain, whereas in the PUFA group it was sunflower oil (rich in 18:2 linoleic acid, an omega-6 acid). The ration was fed for a minimum period of 60 days and thereafter semen was collected for evaluation. The proportion of progressive forward motility was significantly (P<0.05) higher in the PUFA group compared with the maize group. Sperm lipid peroxidation as measured by malondialdehyde formation (µM per 1×10(9) spermatozoa) was significantly (P<0.05) higher in the PUFA group compared with the maize group. When the semen was diluted with Tris-egg yolk-citrate buffer and incubated for 24h at 4°C, the proportions of plasmalemma integrity, the sperm subpopulation positive for functional membrane and acrosomal integrities, and mitochondrial membrane potential were significantly (P<0.05) higher in PUFA-fed than in maize-fed animals. The different sources of energy did not influence the serum and seminal plasma IGF-I levels. The cleavage rate (percentage) did not differ significantly between PUFA- (45.4±4.91) and maize- (44.63±6.8) fed animals. In conclusion, PUFA feeding influenced sperm quality by altering or stabilising membrane integrity. The present study indicates that PUFA may improve semen quality but did not improve in vitro fertilisation.
Marques, M G; de Barros, F R O; Goissis, M D; Cavalcanti, P V; Viana, C H C; Assumpção, M E O D; Visintin, J A
The aim of this study was to evaluate the efficiency of low oxygen tension (5% CO(2) , 5% O(2) and 90% N(2) ) on in vitro oocyte maturation using defined media (0.1% polyvinyl alcohol - PVA) or 10% porcine follicular fluid (PFF)-supplemented media. To achieve this goal, oocytes were evaluated regarding cortical granules (GCs) migration, nuclear maturation and sperm penetration. Oocytes were in vitro matured under different conditions: 5% or 20% O(2) atmosphere and 0.1% PVA- or 10% PFF-supplemented media and evaluated at 0 and 44 h of maturation. To evaluate the migration of CGs and nuclear maturation, by confocal microscopy, oocytes were incubated with 100 μg of FITC-PNA/ml and 10 μg/ml of propidium iodide. To address sperm penetration, after maturation, in vitro fertilization for 6 h and in vitro culture for 18 h, zygotes were incubated with 10 mg/ml Hoechst 33342. Pronuclei and polar bodies were quantified using an epifluorescence microscope. Atmosphere conditions did not affect the CGs migration, but media supplementation did. Oocytes matured in 10% PFF media had a higher percentage of CGs in the oocyte periphery than oocytes matured in PVA-supplemented media. However, this fact did not have effect on in vitro sperm penetration levels. No effect of atmosphere conditions and media supplementation was observed on the rates of metaphase II oocytes. Therefore, the use of low oxygen tension in association with PVA maturation media does not improve the in vitro maturation system of porcine oocytes, because its use did not improve nuclear maturation, CGs migration and zygotes monospermic rates.
Isachenko, Vladimir; Isachenko, Eugenia; Katkov, Igor I; Montag, Markus; Dessole, Salvatore; Nawroth, Frank; Van Der Ven, Hans
Human spermatozoa can be successfully cryopreserved avoiding the use of cryoprotectants through vitrification at very high cooling rates (up to 7.2 x 10(5) degrees C/min). This is achieved by directly plunging a copper cryoloop loaded with a sperm suspension into liquid nitrogen. After storage, vitrified spermatozoa are instantly thawed by melting in an agitated, warm medium. The goal of the present study was to compare the quality of spermatozoa cryopreserved using this rapid vitrification method with that of spermatozoa cooled relatively slowly by preexposure of the loaded cryoloop to liquid nitrogen vapor (-160 degrees C) with speed in the range 150-250 degrees C/min) before immersion into liquid nitrogen. Both cooling modes led to comparable results in terms of the motility, fertilization ability, and DNA integrity of the warmed spermatozoa. In both cases, instant thawing by melting in a warm medium was essential for successful cryopreservation. Our findings suggest that optimal regimes for the cryoprotectant-free cryopreservation of spermatozoa need not be restricted to very fast cooling before storage in liquid nitrogen, a wide range of cooling rates being acceptable. Herein, we discuss the implications of this finding in the light of the physics of extra- and intracellular vitrification.
Sabeti, Parvin; Pourmasumi, Soheila; Rahiminia, Tahereh; Akyash, Fatemeh; Talebi, Ali Reza
Sperm is particularly susceptible to reactive oxygen species (ROS) during critical phases of spermiogenesis. However, the level of seminal ROS is restricted by seminal antioxidants which have beneficial effects on sperm parameters and developmental potentials. Mitochondria and sperm plasma membrane are two major sites of ROS generation in sperm cells. Besides, leukocytes including polymer phonuclear (PMN) leukocytes and macrophages produce broad category of molecules including oxygen free radicals, non-radical species and reactive nitrogen species. Physiological role of ROS increase the intracellular cAMP which then activate protein kinase in male reproductive system. This indicates that spermatozoa need small amounts of ROS to acquire the ability of nuclear maturation regulation and condensation to fertilize the oocyte. There is a long list of intrinsic and extrinsic factors which can induce oxidative stress to interact with lipids, proteins and DNA molecules. As a result, we have lipid peroxidation, DNA fragmentation, axonemal damage, denaturation of the enzymes, over generation of superoxide in the mitochondria, lower antioxidant activity and finally abnormal spermatogenesis. If oxidative stress is considered as one of the main cause of DNA damage in the germ cells, then there should be good reason for antioxidant therapy in these conditions. PMID:27351024
Anakkul, Nitira; Suwimonteerabutr, Junpen; Tharasanit, Theerawat; Khunmanee, Sarawanee; Diloksumpan, Paweena; Berg, Debra K; Techakumphu, Mongkol
Generally, laparoscopic artificial insemination (LAI) provides a higher success rate than of cervical insemination in goats. However, the sperm distribution after LAI in goats remains unknown, particularly when frozen-thawed semen is used. This study evaluated the distribution of frozen-thawed goat spermatozoa after LAI and compared the effects of sperm numbers and deposition sites (unilateral and bilateral sites) on pregnancy rate. In experiment 1, the frozen-thawed spermatozoa were stained either with CellTracker Green CMFDA (CT-Green) or CellTracker Red CMPTX (CT-Red), and in vitro evaluations of viability and motility were performed. In experiment 2, the labeled spermatozoa were deposited via LAI into the left (CT-Green) and right (CT-Red) uterine horns (n = 4). After ovariohysterectomy (6 hours after insemination), the distributions of green- and red-colored spermatozoa were assessed via tissue section, flushing, and the oviductal contents were also collected. Experiment 3 was designed to test the pregnancy rates in a group of 120 does after LAI using different numbers of spermatozoa (60 and 120 × 10(6) sperm per LAI) and different deposition sites. The results demonstrated that the fluorochromes used in this study did not impair sperm motility or viability. Frozen-thawed goat spermatozoa can migrate transuterinally after LAI, as evidenced by the observations of both CT-Green- and CT-Red-labeled spermatozoa in both uterine horns. Lower numbers of spermatozoa (60 × 10(6)) that are inseminated unilaterally (either ipsilateral or contralateral to the site of ovulation) can efficiently be used for LAI in goats (with a 56.67% pregnancy rate).
Berendonck, Bettina; Greven, Hartmut
The female genital structures of the entelegyne spider Latrodectus revivensis are described using semithin sections and scanning electron microscopy. Apart from the tactile hairs overhanging the opening of the atrium, the contact zones of the female epigynum are devoid of any sensilla, indicating that the female does not discriminate in favor or against males due to their genital size or stimulation through copulatory courtship. The dumb-bell shape and the spatial separation of the entrance and the exit of the paired spermathecae suggest that they are functionally of the conduit type. Not described for other entelegyne spiders so far, the small fertilization ducts originating from the spermathecae of each side lead to a common fertilization duct that connects the spermathecae to the uterus externus. During oviposition, it is most likely that spermatozoa are indiscriminately sucked out of the spermathecal lumina by the low pressure produced by the contraction of the muscle extending from the epigynal plate to the common fertilization duct. As no greater amounts of secretion are produced by the female during oviposition, and no activated sperm are present within the female genital tract, the secretion produced by the spermathecal epithelium does not serve in displacement or (selective) activation of spermatozoa. These findings suggest that female L. revivensis are not able to exert cryptic female choice by selectively choosing spermatozoa of certain males.
Snook, R R; Markow, T A; Karr, T L
We report on a form of sperm polymorphism, termed polymegaly, that occurs in species of the Drosophila obscura group. Individual males of species in this group characteristically produce more than one discrete length of nucleated, motile sperm. Hypotheses suggested to explain the evolutionary significance of sperm polymorphism have been either nonadaptive or adaptive, with the latter focusing on sperm competition or nutrient provisioning. These hypotheses assume all sperm types fertilize eggs; however, no data have been gathered to test this assumption. We found that two size classes of sperm are produced and transferred to females in approximately equal numbers by the male; only long sperm persist in significant numbers in female sperm storage organs. Furthermore, we used a DNA-specific dye (bisbenzimide) and sperm-specific antibodies to ask if both sperm types fertilize eggs in Drosophila pseudoobscura. Confocal microscopy and immunofluorescent analyses of fertilized eggs using anti-sperm polyclonal antisera demonstrated that only long sperm participate in fertilization. These data falsify those hypotheses in which all sperm types are assumed to be functionally equivalent (fertilize eggs). Any remaining or new hypotheses for the evolutionary significance of polymegaly must incorporate these findings. Several new areas of research are suggested. Images PMID:7972038
Khalifa, Tarek; Lymberopoulos, Aristotelis
The aim of this experiment was to study the effect of semen extender on sperm chromatin structure and to correlate chromatin integrity with field-fertility of preserved ram semen. Ejaculates of at least 2 × 10(9) sperm/ml and 70 % progressive motility were collected using an artificial vagina from Chios rams (n = 11, 4-6 years old), split-diluted to 1 × 10(9) sperm/ml with milk-egg yolk- and soybean lecithin (Ovixcell®)-based extenders, packaged in 0.5-ml straws and examined after 6, 24 and 48 h of storage at 5 ± 1 °C. Evaluation endpoints were computer-assisted sperm motion analysis, fluorescence-based analysis of chromatin structure by chromomycin A3 and acridine orange assays, and 65-day pregnancy rate (PR) of 34- to 36-h preserved semen after intra-cervical insemination of ewes (n = 154) in progestagen-synchronized estrus. Neither extender nor storage time had any influence on incidence of decondensed chromatin. Unlike Ovixcell® extender, deterioration of sperm motility (P < 0.01) and chromatin stability (P < 0.005) was detected after 48 h of storage in milk-egg yolk extender. Sperm motility accounted for 14.4-18.5 % of variations in chromatin integrity (P < 0.001). No significant difference was found in PR of Ovixcell®- and milk-egg yolk-stored semen. Nevertheless, PR differed between rams (14.3-71.4 %; P < 0.025). Chromatin integrity explained 10.2-56.3 % of variations in PR (P < 0.05-0.01). A pronounced decline in PR (19.1 %) was observed when percentages of decondensed and destabilized chromatin have reached thresholds of 10.5-30 % and 4-9 %, respectively. In conclusion, Ovixcell® is superior to milk-egg yolk extender in preserving chromatin stability and motility. Chromatin defects are negatively associated with sperm fertility.
Kleven, Oddmund; Fossøy, Frode; Laskemoen, Terje; Robertson, Raleigh J; Rudolfsen, Geir; Lifjeld, Jan T
Sperm swimming speed is an important determinant of male fertility and sperm competitiveness. Despite its fundamental biological importance, the underlying evolutionary processes affecting this male reproductive trait are poorly understood. Using a comparative approach in a phylogenetic framework, we tested the predictions that sperm swim faster with (1) increased risk of sperm competition, (2) shorter duration of female sperm storage, and (3) increased sperm length. We recorded sperm swimming speed in 42 North American and European free-living passerine bird species, representing 35 genera and 16 families. We found that sperm swimming speed was positively related to the frequency of extrapair paternity (a proxy for the risk of sperm competition) and negatively associated with clutch size (a proxy for the duration of female sperm storage). Sperm swimming speed was unrelated to sperm length, although sperm length also increased with the frequency of extrapair paternity. These results suggest that sperm swimming speed and sperm length are not closely associated traits and evolve independently in response to sperm competition in passerine birds. Our findings emphasize the significance of both sperm competition and female sperm storage duration as evolutionary forces driving sperm swimming speed.
Knox, R V; Ringwelski, J M; McNamara, K A; Aardsma, M; Bojko, M
Frozen-thawed boar sperm (FTS) has reduced in vitro and in vivo life span compared to liquid semen. Experiments tested whether extenders, thawing procedures, and storage temperatures could extend the fertile life span of FTS. Experiment 1 tested the effect of six extenders on postthaw motility (MOT) and viability (VIA). Straws from boars (n = 6) were thawed, diluted into each extender, and evaluated at 20, 60, and 120 minutes. There was a trend (P = 0.08) for an extender-by-time interaction for MOT and effect of extender and time for MOT (P < 0.0001) and extender (P = 0.10) and time (P < 0.0001) for VIA. Experiment 2 evaluated the effect of temperature and time of thawing on in vitro fertility at intervals after thawing. Straws (0.5 mL) from different boar ejaculates (n = 15) were thawed at 50 °C for 10, 20, or 30 seconds or at 70 °C for 5, 10, or 20 seconds and evaluated at 5, 30, and 60 minutes. There was an effect of thawing treatment on MOT, VIA, and ACR (viable sperm with intact acrosomes, P < 0.0001) and an effect of time of evaluation (P < 0.0001) on MOT and ACR. Thawing at 70 °C for 20 seconds reduced (P < 0.05) MOT, VIA, and ACR compared to other treatments. Experiment 3 tested the effects of storage temperature and time after thawing using 20 ejaculates. Samples were thawed, diluted, and allotted to storage at 17 °C, 26 °C, or 37 °C with evaluation at 2, 6, 12, and 24 hours. There was a storage temperature and time effect and an interaction for MOT and VIA (P < 0.0001). Storage at 17 °C and 26 °C increased (P < 0.05) MOT over all times (38.5%) compared to 37 °C (26%), whereas MOT was reduced at intervals. Viability was also greatest with 17 °C and 26 °C compared to 37 °C and was also affected by time and decreased with time. These results indicate that FTS can be held at 17 °C or 26 °C for up to 2 hours before use and would allow for preparation of multiple doses. These data suggest in vitro fertility of FTS is affected by extenders, thawing
The World Health Organization (WHO) criteria, which include percent motility and sperm concentration, are the only criteria for evaluating sperm quality and conception ability. However, these criteria are insufficient to evaluate the possibility of natural pregnancy. Thus, an index that can directly evaluate the possibility of a natural pregnancy is necessary. A new sperm energy theory without approximation was developed to assess the possibility of natural pregnancy based on mechanical sperm energy. Sperm motility parameters were measured using computer-assisted sperm analysis (CASA) in 129 ejaculated semen samples from 50 men in couples diagnosed with infertility, in which no abnormalities were found in women (sterile group), and 157 ejaculated semen samples from 57 men who had already fathered children in natural pregnancies (control group). A total of 129 subjects were selected from the control group and classified as the fertile group in order of the sample measurement date. The sperm energy index (SEI) and mean sperm energy index (MEI) were accurately obtained according to the methods described by the new sperm energy theory. SEI reflects total mechanical energy of the sperm in a visual field during CASA measurements. MEI reflects the mean mechanical energy of one sperm in a measurement field. All subjects with (MEI)/(SEI) > 2 were assigned to the sterile group. The larger the SEI, the higher was the probability of predicting fertile subjects. The probability of predicting fertile subjects was approximately 60% with a SEI of > 0.5, 70% with a SEI of > 1, 80% with a SEI of > 3, and 90% with a SEI of > 6 in cases where (MEI)/(SEI) is < 2. The data support the view that this novel method can be used to estimate the possibility of a natural pregnancy.
Yamaguchi, S; Funahashi, H
We have reported that artificial insemination (AI) with frozen-thawed boar semen supplemented with caffeine increased the number of uterine sperm by inhibiting the migration of polymorphonuclear leukocytes (PMNs) into the uterine lumen, thereby improving the fertility of gilts and sows. The objective of the present study was to examine the effects of the addition of the antioxidant beta-mercaptoethanol (bME) and caffeine to the thawing solution on the function of frozen-thawed sperm, on the phagocytic activity of PMNs for sperm, and on the fertility of sows after AI. When frozen-thawed sperm were cultured in the presence of 25 or 50 μm bME, sperm capacitation and spontaneous acrosome reactions were inhibited (P < 0.01). There was no effect of bME on phagocytic activity of PMNs for sperm in vitro. When hormonally treated (400 IU of equine chorionic gonadotropin + 200 IU of human chorionic gonadotropin) weaned sows experienced a single intrauterine insemination with frozen-thawed sperm (25 × 10(8) sperm per 50 ml dose) 40 h after subsequent hCG administration, pregnancy and farrowing rates were unaffected by the addition of 50 μm bME (pregnancy rate, 20 vs 21% in controls; farrowing rate, 20 vs 21%; n = 15 and 14, respectively). However, litter size tended to be higher than in the presence of 50 μm bME compared to its absence (10.0 ± 1.0 vs 5.7 ± 1.5, respectively; P < 0.07). Thus, the addition of bME to the thawing solution containing caffeine could be of benefit for improving the function of frozen-thawed sperm without influencing the phagocytic activity of PMNs for sperm. Although there were no statistically significant effects of bME on pregnancy or farrowing rates, the litter size tended to be higher in the sows subjected to a fixed-time single AI treatment with synchronized ovulation.
Bullock, J. G.; Ross, D. A.
The fibre optic Doppler anemometer (FODA) has been used to develop an accurate quantitative method of routinely assessing bull fertility. This method is of importance to the artificial insemination industry because the present qualitative estimation, performed by viewing semen using a microscope, can only set broad limits of quality. Laser light from the FODA was directed into diluted semen samples and the back scattered light was measured. A digital correlator was used to calculate the signal correlation of the back scattered light. The resultant data curves were interpreted in terms of the collective motility and swimming speed of the spermatozoa using a microcomputer. These two parameters are accepted as being indicative of fertility. The accuracy of this method is demonstrated by examination of results obtained in an experiment where enzymes, thought to alter fertility, were added to semen. The effect of the enzymes on the swimming speed and motility was clearly demonstrated.
Masoudi, R; Sharafi, M; Zare Shahneh, A; Towhidi, A; Kohram, H; Zhandi, M; Esmaeili, V; Shahverdi, A
Ram semen cryopreservation is not efficient for artificial insemination in commercial herds. Beneficial effects of dietary fish oil have been evaluated for cryopreservation of ram semen in soybean lecithin (SL) and egg yolk (EY)-based extenders. A factorial study (two diets × two extenders) was used to analyze the effects of two diets supplemented with fish oil (n-3 fatty acid) or palm oil (saturated fatty acids; [SFAs]) to freeze ram semen in two extenders containing SL or EY. Motility characteristics, membrane integrity, abnormal morphology, mitochondria activity, acrosome integrity, apoptotic status, and fertilizing ability were assessed after freeze-thawing. Although diet had significant (P ≤ 0.05) effects on the quality parameters of frozen-thawed sperm, effects of extenders on these traits were not significant (P > 0.05). The higher significant (P ≤ 0.05) percentage of total motility and progressive motility were observed in n-3/SL (44.83 ± 1.56 and 28.33 ± 1.4) and n-3/EY (43.33 ± 1.56 and 28.50 ± 1.4) than SFA/SL (32.16 ± 1.56 and 14.00 ± 1.4) and SFA/EY (31.66 ± 1.56 and 12.66 ± 1.4) groups. Moreover, n-3/SL and n-3/EY produced the higher significant (P ≤ 0.05) percentage of membrane integrity of sperm (39.83 ± 1.4 and 37.33 ± 1.4) than SFA/SL and SFA/EY (29.83 ± 1.4 and 28.5 ± 1.4). For viability results, the higher significant percentage of live sperm was observed in n-3/SL and n-3/EY (43.16 ± 1.38 and 45.66 ± 1.38) than SFA/SL and SFA/EY (28.66 ± 1.38 and 27.5 ± 1.38). For fertility trials, n-3-based diets (n-3/SL and n-3/EY) improved significantly (P ≤ 0.05) pregnancy rate (44% and 46%), parturition rate (42% and 42%), and lambing rate (46% and 44%) compared with the SFA-based diets (SFA/SL and SFA/EY). No interaction effects have been found between diets and extenders (P > 0.05). It seems that dietary fish oil can improve the semen performance after freezing-thawing process and
Shao, Bing; Shi, Linda Z; Nascimento, Jaclyn M; Botvinick, Elliot L; Ozkan, Mihrimah; Berns, Michael W; Esener, Sadik C
Sperm motility is an important concept in fertility research. To this end, single spot laser tweezers have been used to quantitatively analyze the motility of individual sperm. However, this method is limited with throughput (single sperm per spot), lacks the ability of in-situ sorting based on motility and chemotaxis, requires high laser power (hundreds of milliWatts) and can not be used to dynamically monitor changes in sperm swimming behavior under the influence of a laser beam. Here, we report a continuous 3-D ring-shaped laser trap which could be used for multi-level and high-throughput (tens to hundred sperm per ring) sperm sorting based on their motility and chemotaxis. Under a laser power of only tens of milliWatts, human sperm with low to medium velocity are slowed down, stopped, or forced to change their trajectories to swim along the ring due to the optical gradient force in the radial direction. This is the first demonstration of parallel sperm sorting based on motility with optical trapping technology. In addition, by making the sperm swimming along the circumference of the ring, the effect of laser radiation, optical force and external obstacles on sperm energetics are investigated in a more gentle and quantitative way. The application of this method could be extended to motility and bio-tropism studies of other self-propelled cells, such as algae and bacteria.
Ledesma, Alba; Fernández-Alegre, Estela; Cano, Adriana; Hozbor, Federico; Martínez-Pastor, Felipe; Cesari, Andreína
This study was conducted to evaluate the effects of interacting seminal plasma proteins (iSPP) obtained by AV or EE on frozen-thawed ram sperm in order to test the hypothesis whether this fraction could be sufficient to emulate the effect of complete seminal plasma (SP). Additionally, we evaluated whether these proteins have a differential effect between spermatozoa from high and low fertility rams and between breeding and non-breeding seasons. We assessed sperm motility, quality parameters (intracellular reactive oxygen species, membrane fluidity, plasma membrane permeability and mitochondrial activity) and capacitation status. The main findings from this work were: i) iSPP had no effect on sperm motility, whereas SP (AV or EE) addition produced the highest values of total motility (74.13±2.99 and 72.27±2.99 for AV and EE, respectively) and progressive motility (64.97±2.64 and 63.73±2.64 for AV and EE, respectively); ii) iSPP had no effect on sperm quality parameters (p>0.05), but whole SP improved all parameters evaluated. Moreover, SP collected by AV yielded significantly higher viability (44.60±2.87) and sperm with stable plasma membrane (44.56±2.49) comparing with the addition of SP collected by EE (35.80±2.47 and 36.67±1.71, respectively); iii) iSPP and SP collected by EE, but not by AV, reverted molecular signals of capacitation as protein tyrosine phosphorylation caused by freezing temperatures; iv) there were no effects of fertility or season in sperm quality parameters evaluated. This study demonstrated that, although the iSPP have a clear decapacitating effect, including the ability to revert cryo-capacitation indicators, they are not sufficient to emulate the effects of complete SP regarding sperm functional parameters.
Pojprasath, T; Lohachit, C; Techakumphu, M; Stout, T; Tharasanit, T
Cryopreservation of stallion semen is often associated with poor post-thaw sperm quality. Sugars are among the important components of a freezing extender and act as non-permeating cryoprotectants. This study aimed to compare the quality of stallion sperm frozen with glucose, fructose or sorbitol-containing freezing extenders. Semen was collected from six stallions of proven fertility and cryopreserved using a freezing extender containing different types of monosaccharide sugars (glucose, fructose or sorbitol). After thawing, the semen was examined for sperm motility, viability, acrosome integrity, plasma membrane functionality and sperm longevity. The fertility of semen frozen in the presence of sorbitol was also tested by artificial insemination. Sperm quality was significantly decreased following freezing and thawing (P < 0.05). Fructose was inferior for protecting sperm during cryopreservation when compared to sorbitol and glucose (P < 0.05). Although the viability, motility and acrosome integrity of sperm cryopreserved with a glucose-containing extender did not significantly differ from sperm frozen in the sorbitol-based extender when examined at 2 and 4 h post-thaw, all of these parameters plus plasma membrane functionality were improved for sperm frozen in the sorbitol extender than in the glucose extender when examined 10 min post-thaw. Two of four mares (50%) inseminated with semen frozen with a sorbitol-containing freezing extender became pregnant. It is concluded that different sugars have different abilities to protect against cryoinjury during freezing and thawing of stallion sperm. This study demonstrated that an extender containing sorbitol as primary sugar can be used to successfully cryopreserve equine sperm; moreover, the quality of frozen-thawed sperm appeared to be better than when glucose or fructose was the principle sugar in the freezing extender.
Salmon, Vianney M; Castonguay, François; Demers-Caron, Vincent; Leclerc, Pierre; Bailey, Janice L
Cholesterol-loaded cyclodextrin (CLC) is known to improve ram sperm cryosurvival. This study expands on previous research to: (1) determine the mechanism by which CLC improves ram sperm cryosurvival and (2) compare the efficiency of a novel, skim milk-based extender containing CLC to a traditional egg yolk-based extender. Hypothesis #1 was that CLC enhances membrane cholesterol content to increase the resistance of ram sperm to cold and osmotic stress, thereby improving cryosurvival. We first assessed the ability of fresh sperm treated with CLC to withstand cold shock. Second, fresh sperm were treated with CLC to evaluate their tolerance to osmotic stress. Third, to confirm that cholesterol is incorporated into the sperm using CLC, we quantified sperm cholesterol. To test Hypothesis #2 that CLC is most effective in a medium without competing cholesterol, we compared sperm cryosurvival and fertility in skim milk-based extender containing CLC versus in a traditional egg yolk-based freezing extender without CLC. Our data confirmed that CLC treatment improves ram sperm cold shock and osmotic stress resistance, and augments sperm cholesterol content. Semen in skim milk-based extender containing CLC prior to freezing, had more motile sperm with intact acrosomes after thawing compared to semen in egg yolk-based extender. In contrast, sperm plasma membrane integrity and in vivo fertility of the semen cryopreserved in the skim milk-based extender with CLC did not differ from semen that was cryopreserved in egg yolk-based extender. Further research is warranted to combine CLC with other cryoprotection strategies or to modify the insemination protocol.
Cryopreservation of rabbit semen: comparing the effects of different cryoprotectants, cryoprotectant-free vitrification, and the use of albumin plus osmoprotectants on sperm survival and fertility after standard vapor freezing and vitrification.
Rosato, Maria Pina; Iaffaldano, Nicolaia
best recovery of DNA-intact sperm was recorded for BSA plus sucrose compared with semen vitrified without osmoprotectants (P < 0.05). Finally, the cryodiluent combinations BSA/sucrose and BSA/trehalose were compared in an insemination trial. Rabbit does were inseminated with fresh semen (N = 56), semen conventionally cryopreserved in the BSA-based cryodiluents containing 0.1 M sucrose or trehalose (N = 56 per group), or semen vitrified in the presence of 0.25 M sucrose or trehalose (N = 8 per group). Fertility rates and live born kids were similar for semen cryopreserved with BSA/sucrose (77% and 7.6) compared with fresh semen (84% and 8.1) and significantly higher than the figures recorded for the conventionally frozen semen in the BSA/trehalose group (52% and 6.1; P ≤ 0.05). In contrast, only one doe inseminated with semen vitrified in the presence of BSA/sucrose became pregnant, though no kids were delivered. The conclusions to be drawn from our study are: (1) incubation times and concentration toxicities established for the main permeable CPAs used for conventional freezing of rabbit sperm indicated that DMSO 10% was the least damaging; (2) CPA-free vitrification of rabbit semen led to a low or null sperm cryosurvival; and (3) enriching the freezing medium with BSA plus adequate amounts of sucrose or trehalose can improve the cryosurvival of rabbit sperm after conventional freezing or vitrification. In our working conditions, BSA/sucrose was more effective than BSA/trehalose at preserving the in vivo fertilization capacity of rabbit sperm cryopreserved using the standard procedure.
Cryopreservation methods for poultry semen are not reliable for germplasm preservation, especially for turkeys, where fertility rates from frozen/thawed semen are particularly low. The objective was to evaluate cryopreservation methods for effectiveness in promoting cryosurvival and post-thaw funct...
Barranco, I; Tvarijonaviciute, A; Perez-Patiño, C; Alkmin, D V; Ceron, J J; Martinez, E A; Rodriguez-Martinez, H; Roca, J
Paraoxonase 1 (PON-1) is a hydrolytic enzyme present in body fluids, capable of protecting cells against oxidative stress. The hypothesis was hereby to test that PON-1, present in seminal plasma (SP), acts protecting boar spermatozoa when showing a reasonable high activity in the ejaculate. SP-PON-1 activity differed (p < 0.001) among boars (from 0.10 to 0.29 IU/mL). Intra-boar variability was also observed (p < 0.05), but only in two of the 15 boars. SP-PON-1 activity differed among ejaculate portions, showing the spermatozoa-peak portion of spermatozoa-rich ejaculate fraction the highest levels (0.35 ± 0.03 IU/mL, ranging from 0.12 to 0.69) and the post-sperm ejaculate fraction the lowest levels (0.12 ± 0.01 IU/mL, ranging from 0.03 to 0.21). SP-PON-1 activity was positively correlated with the percentage of spermatozoa with rapid and progressive movement (p < 0.01) and negatively correlated with the generation of intracellular reactive oxygen species (p < 0.01) in semen samples after 72 h of liquid storage. SP-PON-1 activity was highest (p < 0.01) in boars with highest farrowing rates. In conclusion, SP-PON-1 activity differed among boars and ejaculate fractions/portions. SP-PON-1 activity was positively correlated with sperm quality and functionality of liquid-stored semen samples and it evidenced a positive association with in vivo fertility.
Salmon, Vianney M; Leclerc, Pierre; Bailey, Janice L
The success of semen cryopreservation depends on sperm membrane integrity and function after thawing. Cholesterol-loaded cyclodextrin (CLC) is used for in vitro incorporation of cholesterol to protect cells against cold temperatures. We hypothesized that CLC treatment also enhances sperm cholesterol content to increase tolerance to osmotic shock and cryoresistance, thereby improving fertility. We confirmed the fact that treatment of goat semen with 3 mg/ml CLC increases sperm cholesterol content using both the Liebermann-Burchard approach and filipin III labeling of membrane cholesterol. Sperm were then treated with or without CLC and cryopreserved. After thawing, sperm cholesterol dramatically fell, even in the presence of CLC, which explains the mechanism of cryocapacitation. CLC treatment, however, maintained a normal prefreeze cholesterol level in sperm after cryopreservation. Furthermore, fresh sperm treated with CLC and subjected to either cold shock or incubated in hypo-, iso-, and hyperosmotic media, designed to mimic stresses associated with freezing/thawing, displayed increased temperature and osmotic tolerance. CLC treatment also improved sperm viability, motility, and acrosome integrity after thawing. Furthermore, CLC treatment did not affect the sperm's ability to undergo in vitro capacitation according to chlortetracycline fluorescence and protein tyrosine phosphorylation. A pilot field trial demonstrated that artificial insemination with sperm that underwent increased cholesterol levels following CLC treatment yielded higher fertility ( ITALIC! P< 0.1) and proliferation ( ITALIC! P< 0.05) rates in vivo than untreated semen from the same ejaculate samples. These observations suggest that CLC treatment could be used to improve cryoprotection during the freezing and thawing of goat sperm.
Crespilho, A M; Nichi, M; Guasti, P N; Freitas-Dell'Aqua, C P; Sá Filho, M F; Maziero, R R; Dell'aqua, J A; Papa, F O
Two experiments were conducted to compare the effectiveness of different extenders conventionally used for semen cryopreservation to maintain the viability and fertility of cooled bull semen. In Experiment 1, sperm samples obtained from 20 Nellore bulls were preserved at 5°C for 48h using two extenders containing 20% of egg yolk [Tris (TRIS-R) and Botu-Bov(®) (BB)] and another composed of 1% soy lecithin [Botu-Bov(®)-Lecithin (BB-L)] as substitutes for animal origin products. The samples were evaluated at 6, 24 and 48h for plasma and acrosomal membrane integrity, quantification of thiobarbituric acid reactive substances (ng of TBARS/10(8) cells) and sperm motility parameters by computer-assisted semen analysis (CASA). In Experiment 2, pregnancy rate (P/AI) of 973 fixed-time artificially inseminated Nellore cows were compared when cows were inseminated with conventionally cryopreserved semen in TRIS-egg yolk glycerol (TRIS-C Control, n=253) or semen cooled for 48h in TRIS-R (n=233), BB (n=247) or BB-L (n=240). Although none of the extenders used was effective on maintaining total progressive motility and cellular integrity throughout the 48-h of the refrigeration period (P<0.01), BB-L conferred greater protection against oxidative stress (P<0.05) than egg yolk-based medias. The P/AI for semen samples preserved in TRIS-C, TRIS-R, BB and BB-L were 39.92(a), 25.32(b), 26.32(b) and 33.33(ab), respectively. These results demonstrate that the three conventional extenders used for semen cryopreservation do not provide the protection required to maintain bull semen fertility under refrigeration for a 48-h period, resulting in reduced pregnancy rates. However, the use of lecithin-based medium instead of egg yolk results in greater protection against lipid peroxidation, producing P/AI results comparable to those obtained using frozen semen.
Álvarez, Cristina; García-Garrido, Carmen; Taronger, Roser; de Merlo, Gaspar González
Background & objectives: The major cause of fertilisation failure after ICSI is failure of the oocyte to initiate the biochemical processes necessary for activation. This inability could be ascribed to cytoplasmic immaturity of those gametes even if they had reached nuclear maturity. The activation of a mature oocyte is characterised by release from metaphase II (MII) arrest and extrusion of the second polar body, followed by pro-nuclear formation. The aim of this study was to evaluate the fate of in vitro matured (IVM) metaphase I (MI) oocytes subjected to intracytoplasmic sperm injection (ICSI) at different time intervals after extrusion of the first polar body (1PB) in in vitro fertilization (IVF) cycles. Methods: A total of 8030 oocytes were collected from 1400 ICSI cycles, 5504 MII at the time of cumulus retrieval. Four hundred eight metaphase II (MII) (27.1%) matured to MII after in vitro culture for 2-26 h and 5389 sibling MII in the moment of oocyte denudation were injected. On the other hand, 49 ICSI cycles containing only MI oocytes at retrieval were injected at three different time intervals after reaching the MII. The intervals were as follows: 2-6 h (n=10), 8-11 h (n=4) and 23-26 h (n=10). Fertilization and development potential were evaluated in both studies. Results: Fertilization, embryo cleavage and quality were significantly lower in IVM MI compared to MII at time of denudation. Pregnancy rate was higher in group MII. Pregnancy was achieved in three embryo transfers when ICSI was performed within 2-6 h (group I) and 8-11 h (group II) after PB extrusion. One pregnancy was obtained in group I and a healthy neonate was born. Interpretation & conclusions: Immature oocytes from women whose ovaries have been stimulated could be matured, fertilized by ICSI, cleaved in vitro and to give rise to a live birth. However, the developmental competence of embryos derived from immature oocytes is reduced, compared with sibling in vivo matured oocytes. Further
Ketabchi, Ali Asghar
Background Cryptozoospermia (CO) is a situation in which spermatozoa cannot be observed in a fresh semen sample unless an extended centrifugation and microscopic search are performed. CO patients are suggested to use only intracytoplasmic sperm injection (ICSI) as infertility treatment. But still there is debate about the choice of sperm source in cryptozoospermic men candidate for ICSI. Objectives This study was conducted to evaluate fertility outcomes in men with idiopathic cryptozoospermia who were treated using ICSI with freshly ejaculated sperm and testis sperm extraction (TESE) or percutaneous epididymal sperm aspiration (PESA). Methods In this prospective cohort study carried out in an academic institution, 83 out of 92 couples with cryptozoospermia undergoing their first ICSI cycle were recruited. These patients were randomly allocated to two groups: group one (n = 42) who produced freshly ejaculated sperm and, group two (n = 41) who produced a sample by TESE or PESA. The groups were analyzed and compared in terms of fertilization rate, cleavage rate, embryo quality, implantation rate, and clinical pregnancy rate. Results There was a significant difference in fertilization rate, embryo quality, implantation rate, and pregnancy rates between the group of surgically extracted sperm and those of naturally ejaculated sperm using conventional ICSI (P < 0.05). Conclusions Sperm quality extracted by percutaneous PESA and TESE procedures increases fertility outcomes compared to naturally ejaculated sperm in men with idiopathic CO. More specifically, embryo quality, which is most relevant to fertility outcome, improved when surgically extracted sperm was used for ICSI. PMID:27896242
Bernie, Aaron M; Ramasamy, Ranjith; Schlegel, Peter N
Azoospermia in men requires microsurgical reconstruction or a procedure for sperm retrieval with assisted reproduction to allow fertility. While the chance of successful retrieval of sperm in men with obstructive azoospermia approaches >90%, the chances of sperm retrieval in men with non-obstructive azoospermia (NOA) are not as high. Conventional procedures such as fine needle aspiration of the testis, testicular biopsy and testicular sperm extraction are successful in 20-45% of men with NOA. With microdissection testicular sperm extraction (micro-TESE), the chance of successful retrieval can be up to 60%. Despite this increased success, the ability to counsel patients preoperatively on their probability of successful sperm retrieval has remained challenging. A combination of variables such as age, serum FSH and inhibin B levels, testicular size, genetic analysis, history of Klinefelter syndrome, history of cryptorchidism or varicocele and histopathology on diagnostic biopsy have provided some insight into the chance of successful sperm retrieval in men with NOA. The goal of this review was to evaluate the preoperative factors that are currently available to predict the outcome for success with micro-TESE.
Maternal inheritance of mitochondrial DNA (mtDNA) in the Pacific oyster (Crassostrea gigas): a preliminary study using mtDNA sequence analysis with evidence of random distribution of MitoTracker-stained sperm mitochondria in fertilized eggs.
Obata, Mayu; Shimizu, Michiyo; Sano, Natsumi; Komaru, Akira
In many bivalve species, paternal and maternal mitochondrial DNA (mtDNA) from sperm and eggs is transmitted to the offspring. This phenomenon is known as doubly uniparental inheritance (DUI). In these species, sperm mtDNA (M type) is inherited by the male gonad of the offspring. Egg mtDNA (F type) is inherited by both male and female somatic cells and female gonadal cells. In Mytilidae, sperm mitochondria are distributed in the cytoplasm of differentiating male germ cells because they are transmitted to the male gonad. In the present study, we investigated maternal inheritance of mtDNA in the Pacific oyster, Crassostrea gigas. Sequence analysis of two mitochondrial non-coding regions revealed an identical sequence pattern in the gametes and adductor muscle samples taken from six males and five females. To observe whether sperm mitochondria were specifically located in the cytoplasm of differentiating germ cells, their distribution was recorded in C. gigas fertilized eggs by vital staining with MitoTracker Green. Although the 1D blastomere was identified in the cytoplasm of differentiating germ cells, sperm mitochondria were located at the 1D blastomere in only 32% of eggs during the 8-cell stage. Thus, in C. gigas, sperm mitochondria do not specifically locate in the germ cell region at the 1D blastomere. We suggest that the distribution of sperm mitochondria is not associated with germ cell formation in C. gigas. Furthermore, as evidenced by the mtDNA sequences of two non-coding regions, we conclude that mitochondrial DNA is maternally inherited in this species.
Lishko, Polina; Clapham, David E.; Navarro, Betsy; Kirichok, Yuriy
Sperm intracellular pH and calcium concentration ([Ca2+]i) are two central factors that control sperm activity within the female reproductive tract. As such, the ion channels of the sperm plasma membrane that alter intracellular sperm [Ca2+] and pH play important roles in sperm physiology and the process of fertilization. Indeed, sperm ion channels regulate sperm motility, control sperm chemotaxis toward the egg in some species, and may trigger the acrosome reaction. Until recently, our understanding of these important molecules was rudimentary due to the inability to patch-clamp spermatozoa and directly record the activity of these ion channels under voltage clamp. Recently, we overcame this technical barrier and developed a method for reproducible application of the patch-clamp technique to mouse and human spermatozoa. This chapter covers important aspects of application of the patch-clamp technique to spermatozoa, such as selection of the electrophysiological equipment, isolation of spermatozoa for patch-clamp experiments, formation of the gigaohm seal with spermatozoa, and transition into the whole-cell mode of recording. We also discuss potential pitfalls in application of the patch-clamp technique to flagellar ion channels. PMID:23522465
Yeates, Sarah E; Einum, Sigurd; Fleming, Ian A; Holt, William V; Gage, Matthew JG
Adaptations at the gamete level (a) evolve quickly, (b) appear sensitive to inbreeding and outbreeding and (c) have important influences on potential to reproduce. We apply this understanding to problems posed by escaped farm salmon and measure their potential to reproduce in the wild. Farm Atlantic salmon (Salmo salar) are a threat to biodiversity, because they escape in large numbers and can introgress, dilute or disrupt locally adapted wild gene pools. Experiments at the whole fish level have found farm reproductive potential to be significant, but inferior compared to wild adults, especially for males. Here, we assess reproductive performance at the gamete level through detailed in vitro comparisons of the form, function, fertility, compatibility and competitiveness of farm versus wild Atlantic salmon sperm and eggs, in conditions mimicking the natural gametic microenvironment, using fish raised under similar environmental conditions. Despite selective domestication and reduced genetic diversity, we find functional equivalence in all farm fish gamete traits compared with their wild ancestral strain. Our results identify a clear threat of farm salmon reproduction with wild fish and therefore encourage further consideration of using triploid farm strains with optimized traits for aquaculture and fish welfare, as triploid fish remain reproductively sterile following escape. PMID:24822083
Kılıç, Niyazi; Özdemir, Özhan; Başar, Hakan Cevdet; Demircan, Fadime; Ekmez, Fırat; Yücel, Oğuz
Background: Ovarian hyperstimulation syndrome (OHSS) is the most serious and potentially life-threatening iatrogenic complication associated with ovarian stimulation during assisted reproductive technology protocols. The aim of this study was to evaluate the role of dopamine agonist as a preventive strategy of OHSS in women at high risk in in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) treatment cycles. Methods: Seventy women at risk to develop OHSS undergoing IVF/ICSI treatment cycle were included. The study group received 0.5 mg of cabergoline for 8 days from the day of human chorionic gonadotropin administration in comparison to those who undergo no treatment for the prevention of OHSS. The reduction of the incidence of OHSS was the primary outcome. Results: The actual incidence of OHSS was 8.33% in the cabergoline group and 20.58% in the control group. Thus, the incidence of OHSS was significantly reduced, by almost 60%, in the cabergoline group in comparison with the control group (relative ratios: 0.4, 95% confidence interval: 0.18–0.79). Conclusion: Prophylactic treatment with the dopamine agonist, cabergoline, reduces the incidence of OHSS in women at high risk undergoing IVF/ICSI treatment. However, the effects of cabergoline on important outcomes, namely, live birth, miscarriage, and congenital abnormalities are still uncertain. PMID:26629467
Cui, Na; Zhang, Jie; Xu, Yueming; Jiang, Lei; Yang, Aimin; Hao, Guimin
Infertility affects millions of couples worldwide resulting in distress and depression. In the past several decades, in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) have been developed with high efficiency and success rate. The possible effects of gonadotropin administration on follicular metabolism have been discussed but the outcomes remain controversial. The aim of this study was to identify whether serum progesterone on the day of human chorionic gonadotropin (hCG) administration and the ratio of serum progesterone and the number of oocyte retrieved (P/O) had a predictive role for the outcomes of IVF/ICSI. Eight hundred and twenty-five patients were enrolled between January 2012 and December 2012. A positive correlation between progesterone and IVF/ICSI outcomes were found in patients with good ovarian response using receiver operating characteristic (ROC) curve. We found that when progesterone level was higher than 1.04 ng/ml in good ovarian responses, the implantation rate and clinical pregnancy rate were both reduced compared to the rates in patients exhibiting lower progesterone level (progesterone≤1.04 ng/ml). Moreover, the rise of serum progesterone on the day of hCG was negatively correlated with luteinizing hormone (LH) level. This study used 1.04 ng/ml as a definition of progesterone elevation and an adverse effect of serum progesterone rise was observed on clinical pregnancy rate.
Bobe, Julien; Labbé, Catherine
Fish egg quality can be defined as the ability of the egg to be fertilized and subsequently develop into a normal embryo. Similarly, sperm quality can be defined as its ability to successfully fertilize an egg and subsequently allow the development of a normal embryo. In the wild or under aquaculture conditions, the quality of fish gametes can be highly variable and is under the influence of a significant number of external factors or broodstock management practices. For these reasons, the topic of gamete quality has received increasing attention. Despite the significant efforts made towards a better understanding of the factors involved in the control of gamete quality, the picture is far from being complete and the control of gamete quality remains an issue in the aquaculture industry. Some of the factors responsible for the observed variability of gamete quality remain largely unknown or poorly understood. In addition very little is known about the cellular and molecular mechanisms involved in the control of egg and sperm quality. In the present review, the molecular and cellular characteristics of fish gametes are presented with a special interest for the mechanisms that could participate in the regulation of gamete quality. Then, after defining egg and sperm quality, and how can it can be accurately estimated or predicted, we provide an overview of the main factors that can impact gamete quality in teleosts.
Theories have suggested that there is a link between protamine concentrations in individual sperm and sperm fertility. At present, biochemical analyses have only been performed on bulk populations and existing methods have not been able to determine what percentage of morphologically normal sperm are biochemically defective and potentially infertile. As part of an investigation into male sperm fertility, nuclear microscopy has been utilized to measure elemental profiles at the single sperm level. By measuring the ratio of Phosphorus to Sulfur the authors have been able to determine the amount of protamine 1 and protamine 2 in individual cells from bulk fertile samples of bull and mouse sperm. Preliminary results show that, for each species, the relative amounts of protamine 1 and protamine 2 in morphologically normal sperm agree well with expected values.
Clark, A G; Aguadé, M; Prout, T; Harshman, L G; Langley, C H
Genes that influence mating and/or fertilization success may be targets for strong natural selection. If females remate frequently relative to the duration of sperm storage and rate of sperm use, sperm displacement may be an important component of male reproductive success. Although it has long been known that mutant laboratory stocks of Drosophila differ in sperm displacement, the magnitude of the naturally occurring genetic variation in this character has not been systematically quantified. Here we report the results of a screen for variation in sperm displacement among 152 lines of Drosophilia melanogaster that were made homozygous for second and/or third chromosomes recovered from natural populations. Sperm displacement was assayed by scoring the progeny of cn;bw females that had been mated sequentially to cn;bw and tested males in either order. Highly significant differences were seen in both the ability to displace sperm that is resident in the female's reproductive tract and in the ability to resist displacement by subsequent sperm. Most lines exhibited nearly complete displacement, having nearly all progeny sired by the second male, but several lines had as few as half the progeny fathered by the second male. Lines that were identified in the screen for naturally occurring variation in sperm displacement were also characterized for single-strand conformation polymorphisms (SSCP) at seven accessory gland protein (Acp) genes, Glucose dehydrogenase (Gld), and Esterase-6 (Est-6). Acp genes encode proteins that are in some cases known to be transmitted to the female in the seminal fluid and are likely candidates for genes that might mediate the phenomenon of sperm displacement. Significant associations were found between particular Acp alleles at four different loci (Acp26Aa/Ab, Acp29B, Acp36DE and Acp53E) and the ability of males to resist displacement by subsequent sperm. There was no correlation between the ability to displace resident sperm and the ability
Murase, Remi; Sato, Hiroyasu; Yamamoto, Kei; Ushida, Ayako; Nishito, Yasumasa; Ikeda, Kazutaka; Kobayashi, Tetsuyuki; Yamamoto, Toshinori; Taketomi, Yoshitaka; Murakami, Makoto
Within the secreted phospholipase A2 (sPLA2) family, group X sPLA2 (sPLA2-X) has the highest capacity to hydrolyze cellular membranes and has long been thought to promote inflammation by releasing arachidonic acid, a precursor of pro-inflammatory eicosanoids. Unexpectedly, we found that transgenic mice globally overexpressing human sPLA2-X (PLA2G10-Tg) displayed striking immunosuppressive and lean phenotypes with lymphopenia and increased M2-like macrophages, accompanied by marked elevation of free ω3 polyunsaturated fatty acids (PUFAs) and their metabolites. Studies using Pla2g10-deficient mice revealed that endogenous sPLA2-X, which is highly expressed in the colon epithelium and spermatozoa, mobilized ω3 PUFAs or their metabolites to protect against dextran sulfate-induced colitis and to promote fertilization, respectively. In colitis, sPLA2-X deficiency increased colorectal expression of Th17 cytokines, and ω3 PUFAs attenuated their production by lamina propria cells partly through the fatty acid receptor GPR120. In comparison, cytosolic phospholipase A2 (cPLA2α) protects from colitis by mobilizing ω6 arachidonic acid metabolites, including prostaglandin E2. Thus, our results underscore a previously unrecognized role of sPLA2-X as an ω3 PUFA mobilizer in vivo, segregated mobilization of ω3 and ω6 PUFA metabolites by sPLA2-X and cPLA2α, respectively, in protection against colitis, and the novel role of a particular sPLA2-X-driven PUFA in fertilization. PMID:26828067
Murase, Remi; Sato, Hiroyasu; Yamamoto, Kei; Ushida, Ayako; Nishito, Yasumasa; Ikeda, Kazutaka; Kobayashi, Tetsuyuki; Yamamoto, Toshinori; Taketomi, Yoshitaka; Murakami, Makoto
Within the secreted phospholipase A2(sPLA2) family, group X sPLA2(sPLA2-X) has the highest capacity to hydrolyze cellular membranes and has long been thought to promote inflammation by releasing arachidonic acid, a precursor of pro-inflammatory eicosanoids. Unexpectedly, we found that transgenic mice globally overexpressing human sPLA2-X (PLA2G10-Tg) displayed striking immunosuppressive and lean phenotypes with lymphopenia and increased M2-like macrophages, accompanied by marked elevation of free ω3 polyunsaturated fatty acids (PUFAs) and their metabolites. Studies usingPla2g10-deficient mice revealed that endogenous sPLA2-X, which is highly expressed in the colon epithelium and spermatozoa, mobilized ω3 PUFAs or their metabolites to protect against dextran sulfate-induced colitis and to promote fertilization, respectively. In colitis, sPLA2-X deficiency increased colorectal expression of Th17 cytokines, and ω3 PUFAs attenuated their production by lamina propria cells partly through the fatty acid receptor GPR120. In comparison, cytosolic phospholipase A2(cPLA2α) protects from colitis by mobilizing ω6 arachidonic acid metabolites, including prostaglandin E2 Thus, our results underscore a previously unrecognized role of sPLA2-X as an ω3 PUFA mobilizerin vivo, segregated mobilization of ω3 and ω6 PUFA metabolites by sPLA2-X and cPLA2α, respectively, in protection against colitis, and the novel role of a particular sPLA2-X-driven PUFA in fertilization.
Pilastro, Andrea; Scaggiante, Marta; Rasotto, Maria B
Sperm competition theory predicts that males should strategically allocate their sperm reserves according to the level of sperm competition, defined as the probability that the sperm of two males compete for fertilizing a given set of ova. Substantial evidence from numerous animal taxa suggests that, at the individual level, sperm expenditure increases when the risk of sperm competition is greater. In contrast, according to the "intensity model" of sperm competition [Parker, G. A., Ball, M. A., Stockley, P. & Gage, M. J. G. (1996) Proc. R. Soc. London Ser. B 263, 1291-1297], when more than two ejaculates compete during a given mating event, sperm expenditure should decrease as the number of competing males increases. Empirical evidence supporting this prediction, however, is still lacking. Here we measured sperm expenditure in two gobiid fishes, the grass (Zosterisessor ophiocephalus) and black goby (Gobius niger), in which up to six sneakers can congregate around the nest of territorial males and release their sperm when females spawn. We show that, in accordance with theory, sneaker males of both species release fewer sperm as the number of competitors increases.
Okunade, Gbolahan W; Miller, Marian L; Pyne, Gail J; Sutliff, Roy L; O'Connor, Kyle T; Neumann, Jonathan C; Andringa, Anastasia; Miller, Daniel A; Prasad, Vikram; Doetschman, Thomas; Paul, Richard J; Shull, Gary E
The relative importance of plasma membrane Ca2+-ATPase (PMCA) 1 and PMCA4 was assessed in mice carrying null mutations in their genes (Atp2b1 and Atp2b4). Loss of both copies of the gene encoding PMCA1 caused embryolethality, whereas heterozygous mutants had no overt disease phenotype. Despite widespread and abundant expression of PMCA4, PMCA4 null (Pmca4-/-) mutants exhibited no embryolethality and appeared outwardly normal. Loss of PMCA4 impaired phasic contractions and caused apoptosis in portal vein smooth muscle in vitro; however, this phenotype was dependent on the mouse strain being employed. Pmca4-/- mice on a Black Swiss background did not exhibit the phenotype unless they also carried a null mutation in one copy of the Pmca1 gene. Pmca4-/- male mice were infertile but had normal spermatogenesis and mating behavior. Pmca4-/- sperm that had not undergone capacitation exhibited normal motility but could not achieve hyperactivated motility needed to traverse the female genital tract. Ultrastructure of the motility apparatus in Pmca4-/- sperm tails was normal, but an increased incidence of mitochondrial condensation indicated Ca2+ overload. Immunoblotting and immunohistochemistry showed that PMCA4 is the most abundant isoform in testis and sperm and that it is localized to the principle piece of the sperm tail, which is also the location of the major Ca2+ channel (CatSper) required for sperm motility. These results are consistent with an essential housekeeping or developmental function for PMCA1, but not PMCA4, and show that PMCA4 expression in the principle piece of the sperm tail is essential for hyperactivated motility and male fertility.
Computer assisted sperm analysis of motility patterns of postthawed epididymal spermatozoa of springbok (Antidorcas marsupialis), impala (Aepyceros melampus), and blesbok (Damaliscus dorcus phillipsi) incubated under conditions supporting domestic cattle in vitro fertilization.
Chatiza, F P; Bartels, P; Nedambale, T L; Wagenaar, G M
The need for information on the reproductive physiology of different wildlife species is important for ex situ conservation using such methods as in vitro fertilization (IVF). Information on species reproductive physiology and evaluation of sperm quality using accurate, objective, repeatable methods, such as computer-assisted sperm analysis (CASA) for ex situ conservation has become a priority. The aim of this study was to evaluate motility patterns of antelope epididymal spermatozoa incubated for 4 h under conditions that support bovine IVF using CASA. Cauda epididymal spermatozoa were collected postmortem from testicles of springbok (N=38), impala (N=26), and blesbok (N=42), and cryopreserved in biladyl containing 7% glycerol. Spermatozoa were thawed and incubated in Capacitation media and modified Tyrode lactate (m-TL) IVF media using a protocol developed for domestic cattle IVF. The study evaluates 14 motility characteristics of the antelope epididymal sperm at six time points using CASA. Species differences in CASA parameters evaluated under similar conditions were observed. Several differences in individual motility parameters at the time points were reported for each species. Epididymal sperm of the different antelope species responded differently to capacitation agents exhibiting variations in hyperactivity. Motility parameters that describe the vigor of sperm decreased over time. Spermatozoa from the different antelope species have different physiological and optimal capacitation and in vitro culture requirements. The interspecies comparison of kinematic parameters of spermatozoa between the antelopes over several end points contributes to comparative sperm physiology which forms an important step in the development of species specific assisted reproductive techniques (ARTs) for ex situ conservation of these species.
Background Sperm cells are the target of strong sexual selection that may drive changes in sperm structure and function to maximize fertilisation success. Sperm evolution is regarded to be one of the major consequences of sperm competition in polyandrous species, however it can also be driven by adaptation to the environmental conditions at the site of fertilization. Strong stabilizing selection limits intra-specific variation, and therefore polymorphism, among fertile sperm (eusperm). Here we analyzed reproductive morphology differences among males employing characteristic alternative mating behaviours, and so potentially different conditions of sperm competition and fertilization environment, in the squid Loligo bleekeri. Results Large consort males transfer smaller (average total length = 73 μm) sperm to a female's internal sperm storage location, inside the oviduct; whereas small sneaker males transfer larger (99 μm) sperm to an external location around the seminal receptacle near the mouth. No significant difference in swimming speed was observed between consort and sneaker sperm. Furthermore, sperm precedence in the seminal receptacle was not biased toward longer sperm, suggesting no evidence for large sperm being favoured in competition for space in the sperm storage organ among sneaker males. Conclusions Here we report the first case, in the squid Loligo bleekeri, where distinctly dimorphic eusperm are produced by different sized males that employ alternative mating behaviours. Our results found no evidence that the distinct sperm dimorphism was driven by between- and within-tactic sperm competition. We propose that presence of alternative fertilization environments with distinct characteristics (i.e. internal or external), whether or not in combination with the effects of sperm competition, can drive the disruptive evolution of sperm size. PMID:21831296
Blengini, Cecilia S; Sergio, Naretto; Gabriela, Cardozo; Giojalas, Laura C; Margarita, Chiaraviglio
In polyandrous species, sperm morphometry and sperm velocity are under strong sexual selection. Although several hypotheses have been proposed to explain the role of sperm competition in sperm trait variation, this aspect is still poorly understood. It has been suggested that an increase in sperm competition pressure could reduce sperm size variation or produce a diversity of sperm to maximize male fertilization success. We aim at elucidating the variability of sperm morphometric traits and velocity in two Tupinambis lizards in the context of sperm competition risk. Sperm traits showed substantial variation at all levels examined: between species, among males within species, and within the ejaculate of individual males. Sperm velocity was found to be positively correlated with flagellum: midpiece ratio, with relatively longer flagella associated with faster sperm. Our results document high variability in sperm form and function in lizards.
Blengini, Cecilia S; Sergio, Naretto; Gabriela, Cardozo; Giojalas, Laura C; Margarita, Chiaraviglio
In polyandrous species, sperm morphometry and sperm velocity are under strong sexual selection. Although several hypotheses have been proposed to explain the role of sperm competition in sperm trait variation, this aspect is still poorly understood. It has been suggested that an increase in sperm competition pressure could reduce sperm size variation or produce a diversity of sperm to maximize male fertilization success. We aim at elucidating the variability of sperm morphometric traits and velocity in two Tupinambis lizards in the context of sperm competition risk. Sperm traits showed substantial variation at all levels examined: between species, among males within species, and within the ejaculate of individual males. Sperm velocity was found to be positively correlated with flagellum: midpiece ratio, with relatively longer flagella associated with faster sperm. Our results document high variability in sperm form and function in lizards. PMID:25505535
Xu, Wenming; Wang, Ke; Chen, Yan; Liang, Xiao Tong; Yu, Mei Kuen; Yue, Huanxun; Tierney, M Louise
The mechanism underlying the non-genomic action of progesterone in sperm functions and related Ca2+ mobilisation remains elusive. Herein we report the expression of gamma-aminobutyric acid type A receptor delta subunit (GABRD) in human and rodent sperm and its involvement in mediating the progesterone-induced acrosome reaction. GABRD was localised in the sperm head/neck region. A δ(392-422)-specific inhibitory peptide against GABRD blocked the progesterone-induced acrosome reaction and the associated increase in intracellular Ca2+. Similarly, an inhibitory effect against both progesterone-induced Ca2+ influx and the acrosome reaction was observed with a P2X2 receptor antagonist. The lack of synergism between the GABRD and P2X2 inhibitors suggests that these two receptors are playing a role in the same pathway. Furthermore, a co-immunoprecipitation experiment demonstrated that GABRD could undergo protein-protein interactions with the Ca2+-conducting P2X2 receptor. This interaction between the receptors could be reduced following progesterone (10μM) inducement. Significantly reduced GABRD expression was observed in spermatozoa from infertile patients with reduced acrosome reaction capacity, suggesting that normal expression of GABRD is critical for the sperm acrosome reaction and thus male fertility. The results of the present study indicate that GABRD represents a novel progesterone receptor or modulator in spermatozoa that is responsible for the progesterone-induced Ca2+ influx required for the acrosome reaction through its interaction with the P2X2 receptor.
Effect of recombinant human follicle-stimulating hormone and luteinizing hormone on in vitro maturation of porcine oocytes evaluated by the subsequent in vitro development of embryos obtained by in vitro fertilization, intracytoplasmic sperm injection, or parthenogenetic activation.
Silvestre, M A; Alfonso, J; García-Mengual, E; Salvador, I; Duque, C C; Molina, I
The aim of this work was to study the effect of recombinant human (rh) FSH and LH on in vitro maturation of pig oocytes compared with a conventional hormonal supplement based on equine (PMSG) and human chorionic gonadotropins (hCG), as evaluated by the developmental ability of 3 types of pig embryos obtained by in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), or artificial activation (ATA). In Exp. 1, one cumulus-oocyte complex group (A group) was supplemented with rh-FSH and rh-LH (0.1 IU/mL each), and the other group (B group) was supplemented with PMSG and hCG (10 IU/mL each). No differences in nuclear maturation between the A and B groups were observed (68.5 vs. 71.4%, respectively). No differences were detected between hormonal treatments in the rates of cleavage or blastocyst formation of ATA, IVF, and ICSI embryos. Total cell number of the embryos was not significantly different in any experimental group (A: 31.1, 28.5, and 19.8 vs. B: 25.2, 25.5, and 20.6 for ATA, IVF, and ICSI embryos, respectively). In Exp. 2, the effects of different concentrations of rh-FSH and rh-LH (0.5, 0.1, or 0.05 IU/mL) in maturation medium on nuclear maturation and in vitro development of embryos obtained by IVF were studied. No effect of different hormonal concentrations on blastocyst formation rates was observed (8.5, 13.0, and 5.7%, respectively). Blastocyst cell number was not different in any experimental group. In conclusion, the results obtained here permit us to substitute PMSG and hCG with rh-FSH and rh-LH and to produce pig embryos obtained by IVF, ICSI, or ATA.
Lee, Won Young; Lee, Ran; Kim, Hee Chan; Lee, Kyung Hoon; Cui, Xiang Shun; Kim, Nam Hyung; Kim, Sang Hyun; Lee, Il Joo; Uhm, Sang Jun; Yoon, Min Jung; Song, Hyuk
The selection of morphologically normal spermatozoa is critical to obtain high breeding performances in boar breeding farms and artificial insemination (AI) centers. Parameters for the selection of semen mainly include total sperm motility, concentration, and morphology. However, these primary parameters are often not reliable for discriminating between normal and abnormal, non-fertilizable spermatozoa. The present study was designed to compare the motion characteristics, fertilization ability using in vitro fertilization (IVF), and acrosome formation of the semen from boars having low (boar number 2012) and normal (boar number 2004 and 2023) breeding performances. The ultimate goal was to identify additional simple and easy criteria for the selection of normal sperm. There was no significant difference between boar 2004 and boar 2023 sperm total motility in computer assisted sperm analysis. However, boar number 2012 semen presented a significantly reduced population of rapid moving spermatozoa and an increased population of slow moving spermatozoa compared to boar numbers 2004 and 2023. Analysis of detailed motion characteristics revealed that sperm from boar number 2012 had significantly reduced motility in progressiveness, average path velocity, straight-line velocity (VSL), curvilinear velocity (VCL), straightness, and linearity. The assessment of the fertilizing ability by IVF also showed that sperm from boar number 2012 showed a fertility rate of 3.4%, whereas sperm from boar number 2023 had a fertility rate of 75.45%. Interestingly, most of the sperm nuclei were found on the peripheral area of the oocytes, suggesting that the sperm from boar number 2012 lacked penetration ability into the oocyte zonapellucida. The acrosome formation analysis using Pisum sativum agglutinin staining demonstrated that the sperm from boar number 2012 had a defect in acrosome formation. Consequently, primary parameters for selecting semen before AI such as motility are not
Sepúlveda, Lilian; Bussalleu, Eva; Yeste, Marc; Bonet, Sergi
Several studies have reported the detrimental effects that bacteriospermia causes on boar sperm quality, but little is known about its effects on IVC. Considering that, the present study sought to evaluate the effects of different concentrations of Pseudomonas aeruginosa on different indicators of capacitation status (sperm viability, membrane lipid disorder, sperm motility kinematics, and protein phosphorylation of boar spermatozoa) after IVC. Flow cytometry and computer assisted sperm analysis (CASA) revealed that the presence of P aeruginosa in boar sperm samples, mostly at concentrations greater than 10(6) CFU/mL, is associated with a significant (P < 0.05) decrease in the percentages of both sperm membrane integrity and sperm with low membrane lipid disorder, and also with a reduction in sperm motility kinetic parameters when compared with results obtained from the control sample, which presented the typical motility pattern of capacitated-like boar spermatozoa. Moreover, Western blot results also showed significant (P < 0.05) changes in the levels of tyrosine, serine, and threonine protein phosphorylation because of bacterial contamination, the decrease in phosphotyrosine levels of p32, a well-known marker of IVC achievement in boar sperm, being the most relevant. Indeed, after 3 hours of IVC, phosphotyrosine levels of p32 in the control sample were 3.13 ± 0.81, whereas in the tubes with 10(6) and 10(8) CFU/mL were 1.05 ± 0.20 and 0.36 ± 0.07, respectively. Therefore, the present study provides novel data regarding the effects of bacterial contamination on boar sperm, suggesting that the presence of P aeruginosa affects the fertilizing ability of boar sperm by altering its ability to accomplish IVC.
R. Hoyos, Luis; Khan, Sana; Dai, Jing; Singh, Manvinder; P. Diamond, Michael; E. Puscheck, Elizabeth; O. Awonuga, Awoniyi
Background: Currently, there is no agreement on the optimal urinary derived human chorionic gonadotropin (u-hCG) dose requirement for initiating final oocyte maturation prior to oocyte collection in in vitro fertilization (IVF), but doses that range from 2500- 15000 IU have been used. We intended to determine whether low dose u-hCG was effective for oocyte maturation in IVF/intracytoplasmic sperm injection (ICSI) cycles independent of body mass index (BMI). Materials and Methods: We retrospectively evaluated a cohort of 295 women who underwent their first IVF/ICSI cycles between January 2003 and December 2010 at the Division of Reproductive Endocrinology and Infertility, Wayne State University, Detroit, MI, USA. Treatment cycles were divided into 3 groups based on BMI (kg/ m2): <25 (n=136), 25- <30 (n=84), and ≥30 (n=75) women. Patients received 5000, 10000 or 15000 IU u-hCG for final maturation prior to oocyte collection. The primary outcome was clinical pregnancy rates (CPRs) and secondary outcome was live birth rates (LBRs). Results: Only maternal age negatively impacted (P<0.001) CPR [odds ratio (OR=0.85, confidence interval (CI: 0.79-0.91)] and LBR (OR=0.84, CI: 0.78-0.90). Conclusion: Administration of lower dose u-hCG was effective for oocyte maturation in IVF and did not affect the CPRs and LBRs irrespective of BMI. Women’s BMI need not be taken into consideration in choosing the appropriate dose of u-hCG for final oocyte maturation prior to oocyte collection in IVF. Only maternal age at the time of IVF negatively influenced CPRs and LBRs in this study. PMID:28367299
Ball, M A; Parker, G A
We examine the risk model in sperm competition games for cases where female fertility increases significantly with sperm numbers (sperm limitation). Without sperm competition, sperm allocation increases with sperm limitation. We define 'average risk' as the probability q that females in the population mate twice, and 'perceived risk' as the information males gain about the sperm competition probability with individual females. If males obtain no information from individual females, sperm numbers increase with q unless sperm limitation is high and one of the two competing ejaculates is strongly disfavoured. If males can distinguish between virgin and mated females, greater sperm allocation to virgins is favoured by high sperm limitation, high q, and by the second male's ejaculate being disfavoured. With high sperm limitation, sperm allocation to virgins increases and to mated females decreases with q at high q levels. With perfect information about female mating pattern, sperm allocation (i) to virgins that will mate again exceeds that to mated females and to virgins that will mate only once, (ii) to virgins that mate only once exceeds that for mated females if q is high and there is high second male disadvantage and (iii) to each type of female can decrease with q if sperm limitation is high, although the average allocation increases at least across low q levels. In general, higher sperm allocation to virgins is favoured by: strong disadvantage to the second ejaculate, high sperm limitation, high average risk and increased information (perceived risk). These conditions may apply in a few species, especially spiders.
He, M; Tan, L
This study explored the correlation between sperm ultrastructure in infertile patients with abnormal sperm morphology and DNA damage. Three unusual sperm morphologies were selected for the experimental group namely case 1 (95% headless sperm), case 2 (98% headless sperm), and case 3 (100% headless sperm), and the control group consisted of 2 subjects (20 and 15% headless sperm). For case 1, the patient was negative for sexually transmitted diseases and had normal semen plasma biochemistry, reproductive hormones, peripheral blood chromosomes, and azoospermia factor (AZF). The aneuploid rate of sperm chromosomes was 0.6%, and DNA damage index of sperm nuclei was 84.4%. The partner of this patient did not get pregnant after artificial reproductive technology assistance. For case 2, the aneuploid rate of sperm chromosomes was 0.8% and DNA damage index of sperm nuclei was 95%. This patient and his spouse did not choose assisted reproduction. For case 3, reproductive hormones, peripheral blood chromosomes and AZF were normal and the aneuploid rate of sperm chromosomes was 0.2%. The wife of this patient gave birth to a healthy baby after ova removal, fertilization and transplantation. For the control group, the aneuploid rate of sperm chromosomes and DNA damage index of sperm nuclei were approximately 0.3 and 30%, respectively. To sum up, sperm ultrastructure of infertile patients suffering from unusual sperm morphology is associated with DNA damage to some extent and can cause infertility. However, pregnancy is still possible through intracytoplasmic sperm injection.
Locatello, Lisa; Poli, Federica; Rasotto, Maria B
Seminal fluid often makes up a large part of an ejaculate, yet most empirical and theoretical studies on sperm competition have focused on how sperm characteristics (number and quality) affect fertilization success. However, seminal fluid influences own sperm performance and may potentially influence the outcome of sperm competition, by also affecting that of rivals. As a consequence males may be expected to allocate their investment in both sperm and seminal fluid in relation to the potential level of competition. Grass goby (Zosterisessor ophiocephalus) is an external fertilizer with guard-sneaker mating tactics, where sperm competition risk varies according to the tactic adopted. Here, we experimentally manipulated grass goby ejaculates by separately combining sperm and seminal fluid from territorial and sneaker males. While sperm of sneaker and territorial males did not differ in their performance when they interacted with their own seminal fluid only, sperm of sneakers increased their velocity and fertilization rate in the presence of territorial males' seminal fluid. By contrast, sneaker males' seminal fluid had a detrimental effect on the performance of territorial males' sperm. Sperm velocity was unaffected by the seminal fluid of males employing the same tactic, suggesting that seminal fluid's effect on rival-tactic sperm is not based on a self/non-self recognition mechanism. Our findings show that cross interactions of sperm and seminal fluid may influence the fertilization success of competing ejaculates with males investing in both sperm and seminal fluid in response to sperm competition risk.
Said, S; Han, M-S; Niwa, K
The possibility of obtaining normal development of rat oocytes following intracytoplasmic injection of rat sperm heads, obtained by sonicating spermatozoa from testes and epididymides, was evaluated. Irrespective of the source of spermatozoa, sperm heads were successfully injected into approximately 45% of oocytes used; after 9-12h of culture, approximately 55% of injected oocytes still had normal morphology. Of the oocytes injected with testicular sperm heads 45% were activated, with a female pronucleus and a second polar body, but significantly more oocytes (approximately 68%) injected with caput and cauda epididymal sperm heads were activated. Male pronuclear formation was observed in 67-84% of the activated oocytes, with no difference in the proportions among the different sources of sperm heads. When zygotes showing two pronuclei and a second polar body at 10h after injection were cultured in conditions that support development of 1-cell embryos produced in vivo, no embryos derived from testicular sperm heads developed to blastocysts after 120 h of culture. Development of embryos derived from cauda sperm heads was significantly higher at all points of assessment, while embryos from caput sperm showed an intermediate degree of development, compared with embryos from testicular spermatozoa. However, similar proportions (2-4%) of 1-cell embryos derived from all three groups of sperm heads developed into normal offspring after transfer to foster mothers; of the limited number of offspring tested, all were fertile. These results demonstrate that sperm heads from all sources tested are similar in their ability to contribute to full development of normal, fertile offspring.
Pope, C E; Crichton, E G; Gómez, M C; Dumas, C; Dresser, B L
Our goals were to: (1) determine if domestic cat sperm could be sorted to high purity by flow cytometry after overnight shipment of cooled samples; (2) evaluate the efficiency with which sorted sperm could be used to generate cat embryos in vitro; and (3) determine if live kittens of predetermined sex could be produced after transfer of embryos derived by IVF using sorted sperm. Semen samples (n=5) from one male were extended in electrolyte-free solution and shipped overnight at 4 degrees C to the sorting facility. Samples were adjusted to 75x10(6)sperm/mL and stained with Hoechst 33342. After 1h at 34.5 degrees C, samples were adjusted to 50x10(6)sperm/mL with 4% egg yolk TALP+0.002% food dye and sorted by high-speed flow cytometry. Later resort analysis confirmed purities of 94% and 83% for X- and Y-chromosome bearing sperm, respectively. Sorted sperm were centrifuged, re-suspended in TEST yolk buffer and shipped overnight to the IVF laboratory. After IVF of in vivo matured oocytes with X-chromosome bearing sperm, cleavage frequency was 62% (54/87). After IVF of IVM oocytes with control, X- or Y-chromosome bearing sperm, the incidence of cleavage was 42% (48/115), 33% (40/120), and 35% (52/150), respectively, and blastocyst development was 53% (21/40), 50% (11/22), and 55% (23/42), respectively (P>0.05). On Day 2, 45 embryos produced by IVF of in vivo matured oocytes with X-chromosome bearing sperm were transferred to the oviduct of four Day 1 recipients, three of which subsequently delivered litters of one, four, and seven female kittens, respectively. In conclusion, we confirmed that sperm sorting technology can be applied to domestic cats and established that kittens of predetermined sex can be produced.
Gañán, N; González, R; Sestelo, A; Garde, J J; Sánchez, I; Aguilar, J M; Gomendio, M; Roldan, E R S
There is limited information on bobcat ejaculate traits and sperm cryopreservation and fertilizing ability. Bobcats were electroejaculated under general anesthesia in November (autumn) and April (spring), and endocrine and sperm traits were characterized. Testosterone (mean+/-SEM: 0.90+/-0.15 ng/mL) was not different between sampling times, but cortisol (average: 13.95+/-1.73 microg/dL) was significantly higher in April. Average number of spermatozoa was 10.0+/-3.4 x 10(6) sperm/ejaculate, with values being significantly higher in April. Sperm motility (average 55.7+/-5.8% motile sperm) was not different between sampling times. The proportion of normal spermatozoa in the ejaculate (average: 14.7+/-2.1%) was significantly higher in April, but the percentage of spermatozoa with intact acrosomes (average: 43.7+/-3.8%) was significantly higher in autumn. Spermatozoa were cryopreserved in a Tes-Tris-based diluent (TEST) or Biladyl, both containing 20% egg yolk and 4% glycerol. Diluted sperm were loaded into straws, refrigerated using a programmable thermoblock with a dry chamber, frozen in nitrogen vapors, thawed, and incubated in F-10 medium with 5% fetal bovine serum for up to 3h. After cryopreservation in TEST, there were about 50% motile sperm upon thawing, and survival was high during incubation post-thaw. Cryopreservation in Biladyl led to similar results, but motility decreased substantially during incubation post-thaw. Bobcat spermatozoa fertilized domestic cat oocytes matured in vitro. Fertilization rates were higher for sperm collected in April and cryopreserved in TEST (46%) than for those cryopreserved using Biladyl (<3%). Fertilized oocytes cleaved in culture, and some (27%) reached the morula stage. This study has allowed us to gain further baseline information on bobcat reproduction, explore sperm cryopreservation conditions, and show that fertilizing capacity can be tested using in vitro-matured cat oocytes. These results will be important for future
Serafini, R; Longobardi, V; Spadetta, M; Neri, D; Ariota, B; Gasparrini, B; Di Palo, R
Aim of this study was to test the reliability of Trypan blue/Giemsa staining to evaluate sperm membrane integrity, acrosomal intactness and morphology in stallion to verify whether it could be applied in vitro as useful tool for sperm fertilizing ability. Fertility data on inseminated mares were collected to evaluate the relationship of sperm quality to pregnancy rates. Forty-one ejaculates were collected from 3 stallions of Salernitano Horse Breed and evaluated for gross appearance, volume, visual motility and membrane integrity with Trypan blue/Giemsa staining and thirty-five mares were inseminated during the breeding season from April to July. Differences among stallions were found in volume, sperm concentration (p < 0.05) and visual motility (p < 0.01). A decrease in sperm motility, concentration (p < 0.05) and total sperm number was found in June-July (p < 0.01). Live sperm with intact acrosome (LSIA) and proximal droplets (PD) were lower (p < 0.01) in June-July, while acrosome reacted sperm (ARS) percentage increased (p < 0.05). No fertility differences were found among stallions with an average fertility per cycle of 44.6% and a pregnancy rate of 68.6%. Higher percentages of LSIA were found in the ejaculates used to inseminate mares that became pregnant vs those used in mares not pregnant (p < 0.05). The significance of LSIA as test variable to verify the reliability of Trypan blue/Giemsa staining was confirmed by Receiver operating characteristic ROC analysis and the sensitivity of the test was 85% at a cut-off value of 48% LSIA. Trypan blue-Giemsa showed to be an accurate method that can be applied on field to evaluate sperm membrane integrity and to identify poor-quality ejaculates.
Talwar, Pankaj; Hayatnagarkar, Suryakant
With absolute normal semen analysis parameters it may not be necessary to shift to specialized tests early but in cases with borderline parameters or with history of fertilization failure in past it becomes necessary to do a battery of tests to evaluate different parameters of spermatozoa. Various sperm function tests are proposed and endorsed by different researchers in addition to the routine evaluation of fertility. These tests detect function of a certain part of spermatozoon and give insight on the events in fertilization of the oocyte. The sperms need to get nutrition from the seminal plasma in the form of fructose and citrate (this can be assessed by fructose qualitative and quantitative estimation, citrate estimation). They should be protected from the bad effects of pus cells and reactive oxygen species (ROS) (leukocyte detection test, ROS estimation). Their number should be in sufficient in terms of (count), structure normal to be able to fertilize eggs (semen morphology). Sperms should have intact and functioning membrane to survive harsh environment of vagina and uterine fluids (vitality and hypo-osmotic swelling test), should have good mitochondrial function to be able to provide energy (mitochondrial activity index test). They should also have satisfactory acrosome function to be able to burrow a hole in zona pellucida (acrosome intactness test, zona penetration test). Finally, they should have properly packed DNA in the nucleus to be able to transfer the male genes (nuclear chromatic decondensation test) to the oocyte during fertilization. PMID:26157295
Bench, Graham S.; Balhorn, Rod; Friz, Alexander M.
Theories suggest there is a link between protamine concentrations in individual sperm and male fertility. Previously, biochemical analyses have used pooled samples containing millions of sperm to determine protamine concentrations. These methods have not been able to determine what percentage of morphologically normal sperm are biochemically defective and potentially infertile. Nuclear microscopy has been utilized to measure elemental profiles at the single sperm level. By measuring the amount of phosphorus and sulfur, the total DNA and protamine content in individual sperm from fertile bull and mouse semen have been determined. These values agree with results obtained from other biochemical analyses. Nuclear microscopy shows promise for measuring elemental profiles in the chromatin of individual sperm. The technique may be able to resolve theories regarding the importance of protamines to male fertility and identify biochemical defects responsible for certain types of male infertility.
Bench, G.S.; Balhorn, R.; Friz, A.M.; Freeman, S.P.H.T.
Theories suggest there is a link between protamine concentrations in individual sperm and male fertility. Previously, biochemical analyses have used pooled samples containing millions of sperm to determine protamine concentrations. These methods have not been able to determine what percentage of morphologically normal sperm are biochemically defective and potentially infertile. Nuclear microscopy has been utilized to measure elemental profiles at the single sperm level. By measuring the amount of phosphorus and sulfur, the total DNA and protamine content in individual sperm from fertile bull and mouse semen have been determined. These values agree with results obtained from other biochemical analyses. Nuclear microscopy shows promise for measuring elemental profiles in the chromatin of individual sperm. The technique may be able to resolve theories regarding the importance of protamines to male fertility and identify biochemical defects responsible for certain types of male infertility.
Vöcking, Oliver; Uhl, Gabriele; Michalik, Peter
Storage of sperm inside the female genital tract is an integral phase of reproduction in many animal species. The sperm storage site constitutes the arena for sperm activation, sperm competition and female sperm choice. Consequently, to understand animal mating systems information on the processes that occur from sperm transfer to fertilization is required. Here, we focus on sperm activation in spiders. Male spiders produce sperm whose cell components are coiled within the sperm cell and that are surrounded by a proteinaceous sheath. These inactive and encapsulated sperm are transferred to the female spermathecae where they are stored for later fertilization. We analyzed the ultrastructural changes of sperm cells during residency time in the female genital system of the orb-web spider Argiope bruennichi. We found three clearly distinguishable sperm conditions: encapsulated sperm (secretion sheath present), decapsulated (secretion sheath absent) and uncoiled sperm (cell components uncoiled, presumably activated). After insemination, sperm remain in the encapsulated condition for several days and become decapsulated after variable periods of time. A variable portion of the decapsulated sperm transforms rapidly to the uncoiled condition resulting in a simultaneous occurrence of decapsulated and uncoiled sperm. After oviposition, only decapsulated and uncoiled sperm are left in the spermathecae, strongly suggesting that the activation process is not reversible. Furthermore, we found four different types of secretion in the spermathecae which might play a role in the decapsulation and activation process.
NAKAI, Michiko; ITO, Junya; SUZUKI, Shun-ichi; FUCHIMOTO, Dai-ichiro; SEMBON, Shoichiro; SUZUKI, Misae; NOGUCHI, Junko; KANEKO, Hiroyuki; ONISHI, Akira; KASHIWAZAKI, Naomi; KIKUCHI, Kazuhiro
In pigs, the efficiency of embryo production after intracytoplasmic sperm injection (ICSI) is still low because of frequent failure of normal fertilization, which involves formation of two polar bodies and two pronuclei. To clarify the reasons for this, we hypothesized that ICSI does not properly trigger sperm-induced fertilization events, especially intracellular Ca2+ signaling, also known as Ca2+ oscillation. We also suspected that the use of in vitro-matured oocytes might negatively affect fertilization events and embryonic development of sperm-injected oocytes. Therefore, we compared the patterns of Ca2+ oscillation, the efficiency of oocyte activation and normal fertilization, and embryo development to the blastocyst stage among in vivo- or in vitro-matured oocytes after ICSI or in vitro fertilization (IVF). Unexpectedly, we found that the pattern of Ca2+ oscillation, such as the frequency and amplitude of Ca2+ rises, in oocytes after ICSI was similar to that in oocytes after IVF, irrespective of the oocyte source. However, half of the oocytes failed to become activated after ICSI and showed no Ca2+ oscillation. Moreover, the embryonic development of normal fertilized oocytes was reduced when in vitro-matured oocytes were used, irrespective of the fertilization method employed. These findings suggest that low embryo production efficiency after ICSI is attributable mainly to poor developmental ability of in vitro-matured oocytes and a lack of Ca2+ oscillation, rather than the pattern of oscillation. PMID:27725347
Evans, Janice P
A crucial step of fertilization is the sperm-egg interaction that allows the two gametes to fuse and create the zygote. In the mouse, CD9 on the egg and IZUMO1 on the sperm stand out as critical players, as Cd9(-/-) and Izumo1(-/-) mice are healthy but infertile or severely subfertile due to defective sperm-egg interaction. Moreover, work on several nonmammalian organisms has identified some of the most intriguing candidates implicated in sperm-egg interaction. Understanding of gamete membrane interactions is advancing through characterization of in vivo and in vitro fertilization phenotypes, including insights from less robust phenotypes that highlight potential supporting (albeit not absolutely essential) players. An emerging theme is that there are varied roles for gamete molecules that participate in sperm-egg interactions. Such roles include not only functioning as fusogens, or as adhesion molecules for the opposite gamete, but also functioning through interactions in cis with other proteins to regulate membrane order and functionality.
Ralt, D; Goldenberg, M; Fetterolf, P; Thompson, D; Dor, J; Mashiach, S; Garbers, D L; Eisenbach, M
Spermatozoa normally encounter the egg at the fertilization site (in the Fallopian tube) within 24 hr after ovulation. A considerable fraction of the spermatozoa ejaculated into the female reproductive tract of mammals remains motionless in storage sites until ovulation, when the spermatozoa resume maximal motility and reach the fertilization site within minutes. The nature of the signal for sperm movement is not known, but one possible mechanism is attraction of spermatozoa to a factor(s) released from the egg. We have obtained evidence in favor of such a possibility by showing that human spermatozoa accumulate in follicular fluid in vitro. This accumulation into follicular fluid was higher by 30-260% than that observed with buffer alone and was highly significant (P less than 10(-8)). Not all of the follicular fluids caused sperm accumulation; however, there was a remarkably strong correlation (P less than 0.0001) between the ability of follicular fluid from a particular follicle to cause sperm accumulation and the ability of the egg, obtained from the same follicle, to be fertilized. These findings suggest that attraction may be a key event in the fertilization process and may give an insight into the mechanism underlying early egg-sperm communication. Images PMID:2011591
Section 2. Visual and Microscopic Approaches for Differentiating Unfertilized Germinal Discs and Early dead Embryos from Pre-Incubated Blastoderms Section 3. Predicting the Duration of fertility by Counting Sperm in the Outer Perivitelline Layer of Laid Eggs...
Evans, Jonathan P.
Sperm competition theory predicts that males should tailor their investment in ejaculates according to the number of rival males competing to fertilize a female’s eggs. Research spanning several taxa supports this prediction by showing that males are often sensitive to the level of sperm competition and adjust their investment in sperm numbers accordingly. More recent work has revealed that males may also tailor the quality of sperm according to the number of males competing for fertilization. Here I test for both effects in guppies ( Poecilia reticulata) in an experiment that simultaneously evaluates the risk and intensity models of sperm competition. The experiment determined whether male guppies adjust the number (stripped ejaculate size) and quality (sperm velocity and viability) of sperm that are primed over a 3-day period according to experimental changes in the perceived level of sperm competition. A total of 136 focal males were initially stripped of all retrievable sperm and assayed for these sperm traits before being allocated at random to one of four treatments simulating different levels of sperm competition risk and intensity. During the 3-day treatment phase, focal males had visual and olfactory access to a sexually receptive (initially virgin) female maintained with different numbers of stimulus males to simulate variation in the risk and intensity of sperm competition. Following this, males were assayed again for the sperm traits. Contrary to predictions, there was no significant change in any of the measured variables among treatments, although qualitatively the patterns for sperm velocity and viability did conform to expectation. The lack of any trend for the number of sperm primed was unequivocal and future work examining the effects of sperm competition on sperm production should focus on whether males differentially allocate sperm numbers among matings that differ in the level of sperm competition.
Demary, Kristian C
In many species females mate with and store sperm from multiple males, and some female insects have evolved multiple compartments for sperm storage. Sperm storage and sperm viability were investigated in two firefly species, Photinus greeni and P. ignitus, which differ in the morphology of the female reproductive tract. Although the primary spermatheca is similar in both species, P. greeni females have an additional, conspicuous outpocketing within the bursa copulatrix whose potential role in sperm storage was investigated in this study. An assay that distinguishes between live and dead sperm was used to examine sperm viability in male seminal vesicles and sperm storage sites within the female reproductive tract. For both Photinus species, sperm from male seminal vesicles showed significantly higher viability compared to sperm from the primary spermatheca of single mated females. In single mated P. greeni females, sperm taken from the channel outpocketing (secondary spermatheca) showed significantly higher viability compared to sperm from the primary spermatheca. This sperm viability difference was not evident in double mated females. There were no significant differences between P. greeni and P. ignitus females in the viability of sperm from the primary spermatheca. These studies contribute to our understanding of post-mating processes that may influence paternity success, and suggest that sexual conflict over control of fertilizations may occur in multiply mated firefly females.
Prakash, Seppan; Prithiviraj, Elumalai; Suresh, Sekar; Lakshmi, Nagella Venkata; Ganesh, Mohanraj Karthik; Anuradha, Murugesan; Ganesh, Lakshmanan; Dinesh, Premavathy
Sperms are highly specialized cells for delivering DNA from male to the ovum. Incredibly, wide degree of diversity in sperm morphology in their basic structures i.e. head, middle piece and tail is found across species. Differences in terms of overall size of the sperm, shape and number of sperm produced are also incredible. One of the key for this variations or diversity in sperm may be associated with female reproductive tract, sperm competition, testicular size and sperm size and number. Establishing a correlation between sperm morphology and factors influencing them is a phenomenal task. In this mini-review these associations and the anatomical and functional adaptations among different from of sperm cells that have evolved to optimize fertilization success are discussed. Nevertheless, explaining these morphological diversities in sperm cells is a challenging question and it seems that evolutionary biologists have only recently engaged in exploring its links and patterns. From the literatures it seems that there is no causal relationship between sperm size and testicular size, however, the accumulated knowledge do indicates evolution of sperm morphology across species has some associations with female reproductive tract, sperm competition and sperm size and number, however interpreting these results for phylogentic correlations should be approached with caution. PMID:24976817
Alvau, Antonio; Escoffier, Jessica; Krapf, Dario; Sánchez-Cárdenas, Claudia; Salicioni, Ana M.; Darszon, Alberto; Visconti, Pablo E.
Mammalian sperm acquire fertilizing ability in the female tract in a process known as capacitation. At the molecular level, capacitation is associated with up-regulation of a cAMP-dependent pathway, changes in intracellular pH, intracellular Ca2+ and an increase in tyrosine phosphorylation. How these signaling systems interact during capacitation is not well understood. Results presented in this study indicate that Ca2+ ions have a biphasic role in the regulation of cAMP-dependent signaling. Media without added Ca2+ salts (nominal zero Ca2+) still contain micromolar concentrations of this ion. Sperm incubated in this medium did not undergo PKA activation or the increase in tyrosine phosphorylation suggesting that these phosphorylation pathways require Ca2+. However, chelation of the extracellular Ca2+ traces by EGTA induced both cAMP-dependent phosphorylation and the increase in tyrosine phosphorylation. The EGTA effect in nominal zero Ca2+ media was mimicked by two calmodulin antagonists, W7 and calmidazolium, and by the calcineurin inhibitor cyclosporine A. These results suggest that Ca2+ ions regulate sperm cAMP and tyrosine phosphorylation pathways in a biphasic manner and that some of its effects are mediated by calmodulin. Interestingly, contrary to wild type mouse sperm, sperm from CatSper1 KO mice underwent PKA activation and an increase in tyrosine phosphorylation upon incubation in nominal zero Ca2+ media. Therefore, sperm lacking Catsper Ca2+ channels behave as wild-type sperm incubated in the presence of EGTA. This latter result suggests that Catsper transports the Ca2+ involved in the regulation of cAMP-dependent and tyrosine phosphorylation pathways required for sperm capacitation. PMID:25597298
Pemberton, Andrew J; Hughes, Roger N; Manríquez, Patricio H; Bishop, John D D
Fertilization success may be severely limited in marine invertebrates that spawn both male and female gametes. In a diverse group of aquatic organisms only sperm are released, with sperm-egg fusion occurring at the mother. Here, we report fertilization kinetics data for two such 'brooding' or 'spermcast' species--representing each major clade of the animal kingdom. High levels of fertilization were achieved at sperm concentrations of two or three orders of magnitude lower than is common with broadcast spawning species. At a concentration of 100 sperm ml(-1), fertilization rates of a bryozoan and colonial ascidian were near maximum, whereas most broadcast spawners would have displayed near complete reproductive failure. A further experiment looked at the rate of uptake of sperm under natural conditions. Results suggested that sperm released at ca. 0.9 m from an acting female could be collected at a rate of 3-12 times greater than the minimum required simply to avoid sperm limitation. Thus, evolutionary pressures on gametic and other reproductive characteristics of many species that release sperm but retain eggs may be quite different from those of broadcast spawners and may confer on the former an enhanced scope for sperm competition and female choice. PMID:14667389
Dejarnette, J M; Leach, M A; Nebel, R L; Marshall, C E; McCleary, C R; Moreno, J F
The conception rates of Holstein heifers after AI with 2.1 or 10 × 10(6) sperm dosages of sex-sorted or conventionally processed sperm were compared. Ejaculates collected by artificial vagina from 8 Holstein sires were cryopreserved at either 2.1 or 10 × 10(6) sperm per dose with or without sorting to 90% purity for X-chromosome-bearing spermatozoa using flow cytometry. All treatments were processed in an egg-yolk (20%), TRIS, glycerol (7%) extender and packaged in color-coded 0.25-mL French straws. Straws (n=350 straws/treatment per sire) were packaged and distributed in aliquots of 12 (3 straws of each treatment) to 51 herds of Holstein heifers. Straw color was recorded in the on-farm record keeping system at the time of AI and retrieved by electronic download. In total, 9,172 services were recovered, providing a mean sample size of 287±3.5 services/sperm dose per semen type within sire (range: 248 to 318). Conception rates were influenced by the main effects of herd, sire, semen type, sperm dosage, and service number. The herd by sperm dosage interaction was the only interaction determined to be significant and implies that some herds (technicians) are more proficient than others at maintaining high levels of conception with decreased sperm dosages. Across herds and sires, the conception rates of each semen type by sperm dosage combination were as follows: 2.1 × 10(6) sex-sorted, 38%, n=2,319; 10 × 10(6) sex-sorted, 44%, n=2,279; 2.1 × 10(6) conventional, 55%, n=2,282; and 10 × 10(6) conventional, 60%, n=2,292. The observation that conception rates of sex-sorted semen were improved by the 10 × 10(6) sperm dosage is encouraging toward the prospectus of development of a commercially available sex-sorted product with improved conception potential over existing technology. However, the failure of the 10 × 10(6) sex-sorted sperm dosage to achieve conception rates comparable to either dosage of conventional semen is somewhat discouraging toward the
Klinefelter, G R; Suarez, J D
Previously we established that a 4-d exposure to chloroethylmethanesulphonate (CEMS), a chemical that significantly reduces serum testosterone (T) levels, resulted in a significant decrease in cauda epididymal sperm reserves in adult male rats while homogenization-resistant testicular spermatid numbers were unaffected. This epididymis-specific alteration occurred whether or not circulating T levels were maintained using T-filled Silastic implants. To determine whether this epididymis-specific decrease in sperm number was the result of decreased epididymal transit time, the vas deferens was ligated at its midpoint just prior to the first of 4 d of exposure to CEMS with and without T implantation. If epididymal sperm transit was accelerated due to treatment, there would be fewer sperm in the caput/corpus and more sperm in the cauda/vas of the treated animals compared to control. The number of sperm in the caput/corpus decreased significantly (P < 0.05) while the number of sperm in the cauda/vas increased significantly in both the CEMS and CEMS + T animals. Daily sperm production was unaffected