Molecular Genetics of Supernumerary Tooth Formation

PubMed Central

Wang, Xiu-Ping; Fan, Jiabing

2011-01-01

Summary Despite advances in the knowledge of tooth morphogenesis and differentiation, relatively little is known about the aetiology and molecular mechanisms underlying supernumerary tooth formation. A small number of supernumerary teeth may be a common developmental dental anomaly, while multiple supernumerary teeth usually have a genetic component and they are sometimes thought to represent a partial third dentition in humans. Mice, which are commonly used for studying tooth development, only exhibit one dentition, with very few mouse models exhibiting supernumerary teeth similar to those in humans. Inactivation of Apc or forced activation of Wnt/β(catenin signalling results in multiple supernumerary tooth formation in both humans and in mice, but the key genes in these pathways are not very clear. Analysis of other model systems with continuous tooth replacement or secondary tooth formation, such as fish, snake, lizard, and ferret, is providing insights into the molecular and cellular mechanisms underlying succesional tooth development, and will assist in the studies on supernumerary tooth formation in humans. This information, together with the advances in stem cell biology and tissue engineering, will pave ways for the tooth regeneration and tooth bioengineering. PMID:21309064

Role of medullary astroglial glutamine synthesis in tooth pulp hypersensitivity associated with frequent masseter muscle contraction.

PubMed

Watase, Tetsuro; Shimizu, Kohei; Ohara, Kinuyo; Komiya, Hiroki; Kanno, Kohei; Hatori, Keisuke; Noma, Noboru; Honda, Kuniya; Tsuboi, Yoshiyuki; Katagiri, Ayano; Shinoda, Masamichi; Ogiso, Bunnai; Iwata, Koichi

2018-01-01

Background The mechanisms underlying tooth pulp hypersensitivity associated with masseter muscle hyperalgesia remain largely underinvestigated. In the present study, we aimed to determine whether masseter muscle contraction induced by daily electrical stimulation influences the mechanical head-withdrawal threshold and genioglossus electromyography activity caused by the application of capsaicin to the upper first molar tooth pulp. We further investigated whether astroglial glutamine synthesis is involved in first molar tooth pulp hypersensitivity associated with masseter muscle contraction. Methods The first molar tooth pulp was treated with capsaicin or vehicle in masseter muscle contraction or sham rats, following which the astroglial glutamine synthetase inhibitor methionine sulfoximine or Phosphate buffered saline (PBS) was applied. Astroglial activation was assessed via immunohistochemistry. Results The mechanical head-withdrawal threshold of the ipsilateral masseter muscle was significantly decreased in masseter muscle contraction rats than in sham rats. Genioglossus electromyography activity was significantly higher in masseter muscle contraction rats than sham rats. Glial fibrillary acidic protein-immunoreactive cell density was significantly higher in masseter muscle contraction rats than in sham rats. Administration of methionine sulfoximine induced no significant changes in the density of glial fibrillary acidic protein-immunoreactive cells relative to PBS treatment. However, mechanical head-withdrawal threshold was significantly higher in masseter muscle contraction rats than PBS-treated rats after methionine sulfoximine administration. Genioglossus electromyography activity following first molar tooth pulp capsaicin treatment was significantly lower in methionine sulfoximine-treated rats than in PBS-treated rats. In the ipsilateral region, the total number of phosphorylated extracellular signal-regulated protein kinase immunoreactive cells in the medullary dorsal horn was significantly smaller upon first molar tooth pulp capsaicin application in methionine sulfoximine-treated rats than in PBS-treated rats. Conclusions Our results suggest that masseter muscle contraction induces astroglial activation, and that this activation spreads from caudal to the obex in the medullary dorsal horn, resulting in enhanced neuronal excitability associated with astroglial glutamine synthesis in medullary dorsal horn neurons receiving inputs from the tooth pulp. These findings provide significant insight into the mechanisms underlying tooth pulp hypersensitivity associated with masseter muscle contraction.

Effects of different types of tooth movement and force magnitudes on the amount of tooth movement and root resorption in rats.

PubMed

Nakano, Takako; Hotokezaka, Hitoshi; Hashimoto, Megumi; Sirisoontorn, Irin; Arita, Kotaro; Kurohama, Takeshi; Darendeliler, M Ali; Yoshida, Noriaki

2014-11-01

To investigate differences in the amount of tooth movement and root resorption that occurred after tipping and bodily movement of the maxillary first molar in rats. Ten-week-old female Wistar rats were divided into two groups according to type of tooth movement and subdivided into four subgroups according to the magnitude of applied force. Nickel-titanium closed-coil springs exerting forces of 10, 25, 50, or 100 g were applied to the maxillary left first molars to induce mesial tooth movement. We designed a novel orthodontic appliance for bodily tooth movement. Tooth movement distance and root resorption were measured using microcomputed tomography and scanning electron and scanning laser microscopy. The amount of tooth movement in the bodily tooth movement group was less than half that in the tipping tooth movement group. The greatest amount of tooth movement occurred in the 10-g tipping and 50-g bodily tooth movement subgroups, and the amount of tooth movement decreased with the application of an excessive magnitude of force. Conversely, root resorption increased when the heavier orthodontic force was applied in both groups. Root resorption in the tipping tooth movement group was approximately twice that in the bodily tooth movement group. Root resorption in the tipping tooth movement group was more pronounced than that in the bodily tooth movement group. Although the amount of tooth movement decreased when extremely heavy forces were applied, root resorption increased in both the tipping and bodily tooth movement groups in rats.

Effects of diabetes on tooth movement and root resorption after orthodontic force application in rats.

PubMed

Arita, K; Hotokezaka, H; Hashimoto, M; Nakano-Tajima, T; Kurohama, T; Kondo, T; Darendeliler, M A; Yoshida, N

2016-05-01

To investigate the effects of diabetes on orthodontic tooth movement and orthodontically induced root resorption in rats. Twenty-three 10-week-old male Sprague-Dawley rats divided into control (n = 7), diabetes (n = 9), and diabetes + insulin (n = 7) groups. Diabetes was induced by administering a single intraperitoneal injection of streptozotocin. Rats with a blood glucose level exceeding 250 mg/dl were assigned to the diabetes group. Insulin was administered daily to the diabetes + insulin group. A nickel-titanium closed-coil spring of 10 g was applied for 2 weeks to the maxillary left first molar in all rats to induce mesial tooth movement. Tooth movement was measured using microcomputed tomography images. To determine the quantity of root resorption, the mesial surfaces of the mesial and distal roots of the first molar were analyzed using both scanning electron microscopy and scanning laser microscopy. After 2 weeks, the amount of tooth movement in the diabetic rats was lower than that in the control rats. Root resorption was also significantly lower in the diabetic rats. These responses of the rats caused by diabetes were mostly diminished by insulin administration. Diabetes significantly reduced orthodontic tooth movement and orthodontically induced root resorption in rats. The regulation of blood glucose level through insulin administration largely reduced these abnormal responses to orthodontic force application. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Biological tooth replacement

PubMed Central

Sartaj, Rachel; Sharpe, Paul

2006-01-01

Teeth develop from a series of reciprocal interactions that take place between epithelium and mesenchyme during development of the mouth that begin early in mammalian embryogenesis. The molecular control of key processes in tooth development such as initiation, morphogenesis and cytodifferentiation are being increasingly better understood, to the point where this information can be used as the basis for approaches to produce biological replacement teeth (BioTeeth). This review outlines the current approaches, ideas and progress towards the production of BioTeeth that could form an alternative method for replacing lost or damaged teeth. PMID:17005022

Inhibition of Wnt signaling by Wise (Sostdc1) and negative feedback from Shh controls tooth number and patterning.

PubMed

Ahn, Youngwook; Sanderson, Brian W; Klein, Ophir D; Krumlauf, Robb

2010-10-01

Mice carrying mutations in Wise (Sostdc1) display defects in many aspects of tooth development, including tooth number, size and cusp pattern. To understand the basis of these defects, we have investigated the pathways modulated by Wise in tooth development. We present evidence that, in tooth development, Wise suppresses survival of the diastema or incisor vestigial buds by serving as an inhibitor of Lrp5- and Lrp6-dependent Wnt signaling. Reducing the dosage of the Wnt co-receptor genes Lrp5 and Lrp6 rescues the Wise-null tooth phenotypes. Inactivation of Wise leads to elevated Wnt signaling and, as a consequence, vestigial tooth buds in the normally toothless diastema region display increased proliferation and continuous development to form supernumerary teeth. Conversely, gain-of-function studies show that ectopic Wise reduces Wnt signaling and tooth number. Our analyses demonstrate that the Fgf and Shh pathways are major downstream targets of Wise-regulated Wnt signaling. Furthermore, our experiments revealed that Shh acts as a negative-feedback regulator of Wnt signaling and thus determines the fate of the vestigial buds and later tooth patterning. These data provide insight into the mechanisms that control Wnt signaling in tooth development and into how crosstalk among signaling pathways controls tooth number and morphogenesis.

Impact of bisphosphonate drug burden in alveolar bone during orthodontic tooth movement in a rat model: a pilot study.

PubMed

Kaipatur, Neelambar R; Wu, Yuchin; Adeeb, Samer; Stevenson, Thomas R; Major, Paul W; Doschak, Michael R

2013-10-01

The aim of this pilot study was to investigate the effect of long-term bisphosphonate drug use (bone burden) on orthodontic tooth movement in a rat model. Sprague Dawley rats were used for orthodontic protraction of the maxillary first molars with nickel-titanium coil springs and temporary anchorage devices as anchorage. Four groups of 5 rats each were included in the study; the first 2 groups were dosed with alendronate or a vehicle during concurrent orthodontic tooth movement. The third and fourth groups were pretreated for 3 months with alendronate or vehicle injections, and bisphosphonate drug treatment was discontinued before orthodontic tooth movement. Tooth movement measurements were obtained at 0, 4, and 8 weeks using high-resolution in-vivo microcomputed tomography, and the tissues were analyzed with histology and dynamic labeling of bone turnover. Appreciable tooth movement was achieved during the 8-week duration of this study with nickel-titanium coil springs and temporary anchorage devices. Both bisphosphonate treatment groups exhibited reduced tooth movement compared with the vehicle-dosed controls with a tendency toward more severe reduction in the bisphosphonate predosed group. Concurrent dosing of the bisphosphonate drug resulted in 56% and 65% reductions in tooth protraction at the 4-week and 8-week times, respectively. The impact of bisphosphonate bone burden in retarding tooth movement was even greater, with 77% and 86% reductions in tooth movement at 4 and 8 weeks, respectively. In this study, we used a robust rat model of orthodontic tooth movement with temporary anchorage devices. It has provided evidence that the bone burden of previous bisphosphonate use will significantly inhibit orthodontic tooth movement. Copyright © 2013 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Impact of ellagic acid in bone formation after tooth extraction: an experimental study on diabetic rats.

PubMed

Al-Obaidi, Mazen M Jamil; Al-Bayaty, Fouad Hussain; Al Batran, Rami; Hussaini, Jamal; Khor, Goot Heah

2014-01-01

To estimate the impact of ellagic acid (EA) towards healing tooth socket in diabetic animals, after tooth extraction. Twenty-four Sprague Dawley male rats weighing 250-300 g were selected for this study. All animals were intraperitoneally injected with 45 mg/kg (b.w.) of freshly prepared streptozotocin (STZ), to induce diabetic mellitus. Then, the animals were anesthetized, and the upper left central incisor was extracted and the whole extracted sockets were filled with Rosuvastatin (RSV). The rats were separated into three groups, comprising 8 rats each. The first group was considered as normal control group and orally treated with normal saline. The second group was regarded as diabetic control group and orally treated with normal saline, whereas the third group comprised diabetic rats, administrated with EA (50 mg/kg) orally. The maxilla tissue stained by eosin and hematoxylin (H&E) was used for histological examinations and immunohistochemical technique. Fibroblast growth factor (FGF-2) and alkaline phosphatase (ALP) were used to evaluate the healing process in the extracted tooth socket by immunohistochemistry test. The reactions of immunohistochemistry for FGF-2 and ALP presented stronger expression, predominantly in EA treated diabetic rat, than the untreated diabetic rat. These findings suggest that the administration of EA combined with RSV may have accelerated the healing process of the tooth socket of diabetic rats, after tooth extraction.

Wnt/β-Catenin Regulates the Activity of Epiprofin/Sp6, SHH, FGF, and BMP to Coordinate the Stages of Odontogenesis

PubMed Central

Aurrekoetxea, Maitane; Irastorza, Igor; García-Gallastegui, Patricia; Jiménez-Rojo, Lucia; Nakamura, Takashi; Yamada, Yoshihiko; Ibarretxe, Gaskon; Unda, Fernando J.

2016-01-01

Background: We used an in vitro tooth development model to investigate the effects of overactivation of the Wnt/β-catenin pathway during odontogenesis by bromoindirubin oxime reagent (BIO), a specific inhibitor of GSK-3 activity. Results: Overactivating the Wnt/β-catenin pathway at tooth initiation upregulated and ectopically expressed the epithelial markers Sonic Hedgehog (Shh), Epiprofin (Epfn), and Fibroblast growth factor8 (Fgf8), which are involved in the delimitation of odontogenic fields in the oral ectoderm. This result indicated an ectopic extension of the odontogenic potential. During tooth morphogenesis, Fibroblast growth factor4 (Fgf4), Fibroblast growth factor10 (Fgf10), Muscle segment homeobox 1 (Msx-1), Bone Morphogenetic protein 4 (Bmp4), and Dickkopf WNT signaling pathway inhibitor 1 (Dkk-1) were overexpressed in first molars cultured with BIO. Conversely, the expression levels of Wingless integration site 10b (Wnt-10b) and Shh were reduced. Additionally, the odontoblast differentiation markers Nestin and Epfn showed ectopic overexpression in the dental mesenchyme of BIO-treated molars. Moreover, alkaline phosphatase activity increased in the dental mesenchyme, again suggesting aberrant, ectopic mesenchymal cell differentiation. Finally, Bmp4 downregulated Epfn expression during dental morphogenesis. Conclusions: We suggest the presence of a positive feedback loop wherein Epfn and β-catenin activate each other. The balance of the expression of these two molecules is essential for proper tooth development. We propose a possible link between Wnt, Bmp, and Epfn that would critically determine the correct patterning of dental cusps and the differentiation of odontoblasts and ameloblasts. PMID:27066482

Sox2+ Stem Cells Contribute to All Epithelial Lineages of the Tooth via Sfrp5+ Progenitors

PubMed Central

Juuri, Emma; Saito, Kan; Ahtiainen, Laura; Seidel, Kerstin; Tummers, Mark; Hochedlinger, Konrad; Klein, Ophir D.; Thesleff, Irma; Michon, Frederic

2012-01-01

SUMMARY The continuously growing mouse incisor serves as a valuable model to study stem cell regulation during organ renewal. Epithelial stem cells are localized in the proximal end of the incisor in the labial cervical loop. Here, we show that the transcription factor Sox2 is a specific marker for these stem cells. Sox2+ cells became restricted to the labial cervical loop during tooth morphogenesis, and they contributed to the renewal of enamel-producing ameloblasts as well as all other epithelial cell lineages of the tooth. The early progeny of Sox2-positive stem cells transiently expressed the Wnt inhibitor Sfrp5. Sox2 expression was regulated by the tooth initiation marker FGF8 and specific miRNAs, suggesting a fine-tuning to maintain homeostasis of the dental epithelium. The identification of Sox2 as a marker for the dental epithelial stem cells will facilitate further studies on their lineage segregation and differentiation during tooth renewal. PMID:22819339

Impact of Ellagic Acid in Bone Formation after Tooth Extraction: An Experimental Study on Diabetic Rats

PubMed Central

Al-Obaidi, Mazen M. Jamil; Al-Bayaty, Fouad Hussain; Hussaini, Jamal; Khor, Goot Heah

2014-01-01

Objectives. To estimate the impact of ellagic acid (EA) towards healing tooth socket in diabetic animals, after tooth extraction. Methods. Twenty-four Sprague Dawley male rats weighing 250–300 g were selected for this study. All animals were intraperitoneally injected with 45 mg/kg (b.w.) of freshly prepared streptozotocin (STZ), to induce diabetic mellitus. Then, the animals were anesthetized, and the upper left central incisor was extracted and the whole extracted sockets were filled with Rosuvastatin (RSV). The rats were separated into three groups, comprising 8 rats each. The first group was considered as normal control group and orally treated with normal saline. The second group was regarded as diabetic control group and orally treated with normal saline, whereas the third group comprised diabetic rats, administrated with EA (50 mg/kg) orally. The maxilla tissue stained by eosin and hematoxylin (H&E) was used for histological examinations and immunohistochemical technique. Fibroblast growth factor (FGF-2) and alkaline phosphatase (ALP) were used to evaluate the healing process in the extracted tooth socket by immunohistochemistry test. Results. The reactions of immunohistochemistry for FGF-2 and ALP presented stronger expression, predominantly in EA treated diabetic rat, than the untreated diabetic rat. Conclusion. These findings suggest that the administration of EA combined with RSV may have accelerated the healing process of the tooth socket of diabetic rats, after tooth extraction. PMID:25485304

BMPs and FGFs target Notch signalling via jagged 2 to regulate tooth morphogenesis and cytodifferentiation

PubMed Central

Mitsiadis, Thimios A.; Graf, Daniel; Luder, Hansueli; Gridley, Thomas; Bluteau, Gilles

2010-01-01

The Notch signalling pathway is an evolutionarily conserved intercellular signalling mechanism that is essential for cell fate specification and proper embryonic development. We have analysed the expression, regulation and function of the jagged 2 (Jag2) gene, which encodes a ligand for the Notch family of receptors, in developing mouse teeth. Jag2 is expressed in epithelial cells that give rise to the enamel-producing ameloblasts from the earliest stages of tooth development. Tissue recombination experiments showed that its expression in epithelium is regulated by mesenchyme-derived signals. In dental explants cultured in vitro, the local application of fibroblast growth factors upregulated Jag2 expression, whereas bone morphogenetic proteins provoked the opposite effect. Mice homozygous for a deletion in the Notch-interaction domain of Jag2 presented a variety of severe dental abnormalities. In molars, the crown morphology was misshapen, with additional cusps being formed. This was due to alterations in the enamel knot, an epithelial signalling structure involved in molar crown morphogenesis, in which Bmp4 expression and apoptosis were altered. In incisors, cytodifferentiation and enamel matrix deposition were inhibited. The expression of Tbx1 in ameloblast progenitors, which is a hallmark for ameloblast differentiation and enamel formation, was dramatically reduced in Jag2−/− teeth. Together, these results demonstrate that Notch signalling mediated by Jag2 is indispensable for normal tooth development. PMID:20685737

The regulation of tooth morphogenesis is associated with epithelial cell proliferation and the expression of Sonic hedgehog through epithelial-mesenchymal interactions.

PubMed

Ishida, Kentaro; Murofushi, Mayumi; Nakao, Kazuhisa; Morita, Ritsuko; Ogawa, Miho; Tsuji, Takashi

2011-02-18

Ectodermal organs, such as the tooth, salivary gland, hair, and mammary gland, develop through reciprocal epithelial-mesenchymal interactions. Tooth morphologies are defined by the crown width and tooth length (macro-morphologies), and by the number and locations of the cusp and roots (micro-morphologies). In our current study, we report that the crown width of a bioengineered molar tooth, which was reconstructed using dissociated epithelial and mesenchymal cells via an organ germ method, can be regulated by the contact area between epithelial and mesenchymal cell layers. We further show that this is associated with cell proliferation and Sonic hedgehog (Shh) expression in the inner enamel epithelium after the germ stage has formed a secondary enamel knot. We also demonstrate that the cusp number is significantly correlated with the crown width of the bioengineered tooth. These findings suggest that the tooth micro-morphology, i.e. the cusp formation, is regulated after the tooth width, or macro-morphology, is determined. These findings also suggest that the spatiotemporal patterning of cell proliferation and the Shh expression areas in the epithelium regulate the crown width and cusp formation of the developing tooth. Copyright © 2011 Elsevier Inc. All rights reserved.

Neurofibromin interacts with CRMP-2 and CRMP-4 in rat brain

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

Lin, Y.-L.; Hsueh, Y.-P., E-mail: yph@gate.sinica.edu.tw

Neurofibromin, encoded by the neurofibromatosis type 1 (NF1) gene, regulates the Ras and cAMP pathways and plays a role in proliferation and neuronal morphogenesis. The details of the molecular mechanism of neurofibromin action in these processes are still unclear. In this study, immunoprecipitation and proteomics were used to identify novel proteins from rat brain that interact with neurofibromin. Mass spectrometry analysis showed that two proteins, the collapsin response mediator protein-2 (CRMP-2) and propionyl-CoA carboxylase alpha chain (PCCA), associated with neurofibromin. Immunoprecipitation-immunoblotting analysis confirmed the interactions between neurofibromin and CRMP-2 and CRMP-4, but not CRMP-1, in rat brain. CDK5, a kinasemore » that regulates CRMP-2 in axonal outgrowth, was required for the interaction between neurofibromin and CRMP-2. Since both neurofibromin and CRMP proteins are involved in proliferation and axonal morphogenesis, these results suggest that the interaction with CRMPs contributes to the function of neurofibromin in tumorigenesis and neuronal morphogenesis.« less

Epithelial stratification and placode invagination are separable functions in early morphogenesis of the molar tooth

PubMed Central

Li, Jingjing; Chatzeli, Lemonia; Panousopoulou, Eleni; Tucker, Abigail S.; Green, Jeremy B. A.

2016-01-01

Ectodermal organs, which include teeth, hair follicles, mammary ducts, and glands such as sweat, mucous and sebaceous glands, are initiated in development as placodes, which are epithelial thickenings that invaginate and bud into the underlying mesenchyme. These placodes are stratified into a basal and several suprabasal layers of cells. The mechanisms driving stratification and invagination are poorly understood. Using the mouse molar tooth as a model for ectodermal organ morphogenesis, we show here that vertical, stratifying cell divisions are enriched in the forming placode and that stratification is cell division dependent. Using inhibitor and gain-of-function experiments, we show that FGF signalling is necessary and sufficient for stratification but not invagination as such. We show that, instead, Shh signalling is necessary for, and promotes, invagination once suprabasal tissue is generated. Shh-dependent suprabasal cell shape suggests convergent migration and intercalation, potentially accounting for post-stratification placode invagination to bud stage. We present a model in which FGF generates suprabasal tissue by asymmetric cell division, while Shh triggers cell rearrangement in this tissue to drive invagination all the way to bud formation. PMID:26755699

The Effect of Ovariectomy and Orchiectomy on Orthodontic Tooth Movement and Root Resorption in Wistar Rats.

PubMed

Seifi, Massoud; Ezzati, Baharak; Saedi, Sara; Hedayati, Mehdi

2015-12-01

Root resorption (RR) after orthodontic tooth movement (OTM) is known as a multifactorial complication of orthodontic treatments. Hormonal deficiencies and their effect on bone turnover are reported to have influences on the rate of tooth movement and root resorption. This study was designed to evaluate the effect of female and male steroid sex hormones on tooth movement and root resorption. Orthodontic appliances were placed on the right maxillary first molars of 10 ovariectomized female and 10 orchiectomized male Wistar rats as experimental groups and 10 female and 10 male healthy Wistar rats as control groups. NiTi closed-coil springs (9mm, Medium, 011"×.030", Ortho Technology(®); Tampa, Florida) were placed between the right incisors and the first right maxillary molars to induce tipping movement in the first molars with the application of a 60g force. After 21 days, the rats were sacrificed and tooth movement was measured by using a digital caliper (Guanglu, China). Orthodontic induced root resorption (OIRR) was assessed by histomorphometric analysis after hematoxylin and eosin staining of sections of the mesial root. The rate of tooth movement was significantly higher in all female rats, with the root resorption being lower in the experimental group. The rate of tooth movement in experimental male rats was significantly higher than the control group (p= 0.001) and the rate of root resorption was significantly lower in the experimental group (p= 0.001). It seems that alterations in plasma levels of estrogen, progesterone, and testosterone hormones can influence the rate of OTM and RR. The acceleration in tooth movement increased OTM and decreased RR.

Examination of extremely low frequency electromagnetic fields on orthodontic tooth movement in rats

PubMed Central

Dogru, Mehmet; Akpolat, Veysi; Dogru, Arzum Guler; Karadede, Beyza; Akkurt, Atilim; Karadede, M. Irfan

2014-01-01

The purpose of this study was to evaluate whether 50 Hz extremely low frequency electromagnetic fields (ELF-EMFs) affect the amount of orthodontic tooth movement in rats. The experiments were performed on 18 male Sprague-Dawley rats. The rats were randomly divided into three groups (n = 6): cage-control (Cg-Cnt) group (n = 6); sinusoidal electromagnetic field (SEMF) group (n = 6); and pulsed electromagnetic field (PEMF) group (n = 6). In SEMF and PEMF groups, rats were subjected to 1.5 mT EMF exposure eight hours per day for eight days. In order to obtain tooth movement, holes were drilled on the right and left maxillary central incisors of the rats at a distance 1.5–2 mm away from the gingiva and 20 g of orthodontic forces were applied to the teeth. Generated linear model for repeated measures and Bonferroni tests were used to evaluate the differences between the groups. Interactions among groups by days were found by using Pillai's trace multivariate test. The results showed that significant differences were present among the groups (F = 5.035; p = 0.03) according to the extent of tooth movement. Significant differences between the amount of tooth movements were determined especially after the fifth day and the following days six, seven and eight (p < 0.001). Within the limitations, according to the results of the present study, the application of ELF-EMF accelerated the orthodontic tooth movement in rats. PMID:26019497

The use of different analgesics in orthodontic tooth movements.

PubMed

Hammad, Shaza M; El-Hawary, Yousry M; El-Hawary, Amira K

2012-09-01

To provide a semi-quantitative assessment of the effect of different analgesics (celecoxib, ketorolac, and paracetamol) on tooth movement and bone resorption using immunohistochemical staining of matrix metalloproteinase-13 (MMP-13). Forty white male rats (12-weeks old; body weight: 230-250 g) were divided into four groups (10 rats each) and were given the treatment once a day for 2 consecutive months. Group A (control group) rats were given the reverse osmosis water; group B rats were given 10 mg/kg celecoxib; group C rats were given 3 mg/kg ketorolac; and group D rats were given 150 mg/kg paracetamol. A precalibrated closed Sentalloy coil spring was placed inside each rat mouth to deliver a constant force of 50 cN. The magnitude of tooth movement was measured intraorally. After 2 months, the rats were sacrificed, and the sections were mounted on L-polylysine-coated glass slides. Slides from each specimen were stained with hematoxylin and eosin, and others were stained with MMP-13. Data were analyzed with the one-way analysis of variance (ANOVA). Celecoxib, ketorolac, and paracetamol groups showed tooth movement of 1.81 ± 0.43 mm, 1.13 ± 0.28 mm, and 1.08 ± 0.27 mm, respectively. The mean number of MMP-13-positive osteoclasts was highest in celecoxib-treated group followed by the control group and was decreased in the ketorolac and paracetamol groups. Comparing all groups to the control revealed significant differences (P < .05). Administration of celecoxib did not reduce bone resorption or interfere with tooth movement in rats compared to other analgesics tested (ketorolac and paracetamol).

Periodontal CGRP contributes to orofacial pain following experimental tooth movement in rats.

PubMed

Long, Hu; Liao, Lina; Gao, Meiya; Ma, Wenqiang; Zhou, Yang; Jian, Fan; Wang, Yan; Lai, Wenli

2015-08-01

Calcitonin-related gene peptide (CGRP) plays an important role in orofacial inflammatory pain. The aim of this study was to determine whether periodontal CGRP contributes to orofacial pain induced by experimental tooth movement in rats. Male Sprague-Dawley rats were used in this study. Closed coil springs were used to deliver forces. Rats were euthanized on 0d, 1d, 3d, 5d, 7d, and 14d following experimental tooth movement. Then, alveolar bones were obtained for immunostaining of periodontal tissues against CGRP. Two hours prior to euthanasia on each day, orofacial pain levels were assessed through rat grimace scale. CGRP and olcegepant (CGRP receptor antagonist) were injected into periodontal tissues to verify the roles of periodontal CGRP in orofacial pain induced by experimental tooth movement. Periodontal CGRP expression levels and orofacial pain levels were elevated on 1d, 3d, 5d, and 7d following experimental tooth movement. The two indices were significantly correlated with each other and fitted into a dose-response model. Periodontal administration of CGRP could elevate periodontal CGRP expressions and exacerbate orofacial pain. Moreover, olcegepant administration could decrease periodontal CGRP expressions and alleviate orofacial pain. Therefore, periodontal CGRP plays an important role in pain transmission and modulation following experimental tooth movement. We suggest that it may participate in a positive feedback aiming to amplify orofacial pain signals. Copyright © 2015 Elsevier B.V. All rights reserved.

Stage-specific differential gene expression profiling and functional network analysis during morphogenesis of diphyodont dentition in miniature pigs, Sus Scrofa

PubMed Central

2014-01-01

Background Our current knowledge of tooth development derives mainly from studies in mice, which have only one set of non-replaced teeth, compared with the diphyodont dentition in humans. The miniature pig is also diphyodont, making it a valuable alternative model for understanding human tooth development and replacement. However, little is known about gene expression and function during swine odontogenesis. The goal of this study is to undertake the survey of differential gene expression profiling and functional network analysis during morphogenesis of diphyodont dentition in miniature pigs. The identification of genes related to diphyodont development should lead to a better understanding of morphogenetic patterns and the mechanisms of diphyodont replacement in large animal models and humans. Results The temporal gene expression profiles during early diphyodont development in miniature pigs were detected with the Affymetrix Porcine GeneChip. The gene expression data were further evaluated by ANOVA as well as pathway and STC analyses. A total of 2,053 genes were detected with differential expression. Several signal pathways and 151 genes were then identified through the construction of pathway and signal networks. Conclusions The gene expression profiles indicated that spatio-temporal down-regulation patterns of gene expression were predominant; while, both dynamic activation and inhibition of pathways occurred during the morphogenesis of diphyodont dentition. Our study offers a mechanistic framework for understanding dynamic gene regulation of early diphyodont development and provides a molecular basis for studying teeth development, replacement, and regeneration in miniature pigs. PMID:24498892

Orthodontic tooth movement and root resorption in ovariectomized rats treated by systemic administration of zoledronic acid.

PubMed

Sirisoontorn, Irin; Hotokezaka, Hitoshi; Hashimoto, Megumi; Gonzales, Carmen; Luppanapornlarp, Suwannee; Darendeliler, M Ali; Yoshida, Noriaki

2012-05-01

The effect of zoledronic acid, a potent and novel bisphosphonate, on tooth movement and orthodontically induced root resorption in osteoporotic animals systemically treated with zoledronic acid as similarly used in postmenopausal patients has not been elucidated. Therefore, this study was undertaken. Fifteen 10-week-old female Wistar rats were divided into 3 groups: ovariectomy, ovariectomy + zoledronic acid, and control. Only the ovariectomy and ovariectomy + zoledronic acid groups underwent ovariectomies. Two weeks after the ovariectomy, zoledronic acid was administered only to the ovariectomy + zoledronic acid group. Four weeks after the ovariectomy, 25-g nickel-titanium closed-coil springs were applied to observe tooth movement and orthodontically induced root resorption. There were significant differences in the amounts of tooth movement and orthodontically induced root resorption between the ovariectomy and the control groups, and also between the ovariectomy and the ovariectomy + zoledronic acid groups. There was no statistically significant difference in tooth movement and orthodontically induced root resorption between the ovariectomy + zoledronic acid and the control groups. Zoledronic acid inhibited significantly more tooth movement and significantly reduced the severity of orthodontically induced root resorption in the ovariectomized rats. The ovariectomy + zoledronic acid group showed almost the same results as did the control group in both tooth movement and orthodontically induced root resorption. Zoledronic acid inhibits excessive orthodontic tooth movement and also reduces the risk of severe orthodontically induced root resorption in ovariectomized rats. Copyright © 2012 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Making teeth to order: conserved genes reveal an ancient molecular pattern in paddlefish (Actinopterygii)

PubMed Central

Smith, Moya M.; Johanson, Zerina; Butts, Thomas; Ericsson, Rolf; Modrell, Melinda; Tulenko, Frank J.; Davis, Marcus C.; Fraser, Gareth J.

2015-01-01

Ray-finned fishes (Actinopterygii) are the dominant vertebrate group today (+30 000 species, predominantly teleosts), with great morphological diversity, including their dentitions. How dental morphological variation evolved is best addressed by considering a range of taxa across actinopterygian phylogeny; here we examine the dentition of Polyodon spathula (American paddlefish), assigned to the basal group Acipenseriformes. Although teeth are present and functional in young individuals of Polyodon, they are completely absent in adults. Our current understanding of developmental genes operating in the dentition is primarily restricted to teleosts; we show that shh and bmp4, as highly conserved epithelial and mesenchymal genes for gnathostome tooth development, are similarly expressed at Polyodon tooth loci, thus extending this conserved developmental pattern within the Actinopterygii. These genes map spatio-temporal tooth initiation in Polyodon larvae and provide new data in both oral and pharyngeal tooth sites. Variation in cellular intensity of shh maps timing of tooth morphogenesis, revealing a second odontogenic wave as alternate sites within tooth rows, a dental pattern also present in more derived actinopterygians. Developmental timing for each tooth field in Polyodon follows a gradient, from rostral to caudal and ventral to dorsal, repeated during subsequent loss of teeth. The transitory Polyodon dentition is modified by cessation of tooth addition and loss. As such, Polyodon represents a basal actinopterygian model for the evolution of developmental novelty: initial conservation, followed by tooth loss, accommodating the adult trophic modification to filter-feeding. PMID:25788604

Long-term neuroplasticity of the face primary motor cortex and adjacent somatosensory cortex induced by tooth loss can be reversed following dental implant replacement in rats.

PubMed

Avivi-Arber, Limor; Lee, Jye-Chang; Sood, Mandeep; Lakschevitz, Flavia; Fung, Michelle; Barashi-Gozal, Maayan; Glogauer, Michael; Sessle, Barry J

2015-11-01

Tooth loss is common, and exploring the neuroplastic capacity of the face primary motor cortex (face-M1) and adjacent primary somatosensory cortex (face-S1) is crucial for understanding how subjects adapt to tooth loss and their prosthetic replacement. The aim was to test if functional reorganization of jaw and tongue motor representations in the rat face-M1 and face-S1 occurs following tooth extraction, and if subsequent dental implant placement can reverse this neuroplasticity. Rats (n = 22) had the right maxillary molar teeth extracted under local and general anesthesia. One month later, seven rats had dental implant placement into healed extraction sites. Naive rats (n = 8) received no surgical treatment. Intracortical microstimulation (ICMS) and recording of evoked jaw and tongue electromyographic responses were used to define jaw and tongue motor representations at 1 month (n = 8) or 2 months (n = 7) postextraction, 1 month postimplant placement, and at 1-2 months in naive rats. There were no significant differences across study groups in the onset latencies of the ICMS-evoked responses (P > 0.05), but in comparison with naive rats, tooth extraction caused a significant (P < 0.05) and sustained (1-2 months) decreased number of ICMS-defined jaw and tongue sites within face-M1 and -S1, and increased thresholds of ICMS-evoked responses in these sites. Furthermore, dental implant placement reversed the extraction-induced changes in face-S1, and in face-M1 the number of jaw sites even increased as compared to naive rats. These novel findings suggest that face-M1 and adjacent face-S1 may play a role in adaptive mechanisms related to tooth loss and their replacement with dental implants. © 2015 Wiley Periodicals, Inc.

The epidemiology of supernumerary teeth and the associated molecular mechanism

PubMed Central

Lu, Xi; Yu, Fang; Liu, Junjun; Cai, Wenping; Zhao, Yumei; Zhao, Shouliang; Liu, Shangfeng

2017-01-01

ABSTRACT Supernumerary teeth are common clinical dental anomalies. Although various studies have provided abundant information regarding genes and signaling pathways involved in tooth morphogenesis, which include Wnt, FGF, BMP, and Shh, the molecular mechanism of tooth formation, especially for supernumerary teeth, is still unclear. In the population, some cases of supernumerary teeth are sporadic, while others are syndrome-related with familial hereditary. The prompt and accurate diagnosis of syndrome related supernumerary teeth is quite important for some distinctive disorders. Mice are the most commonly used model system for investigating supernumerary teeth. The upregulation of Wnt and Shh signaling in the dental epithelium results in the formation of multiple supernumerary teeth in mice. Understanding the molecular mechanism of supernumerary teeth is also a component of understanding tooth formation in general and provides clinical guidance for early diagnosis and treatment in the future. PMID:28598258

Cola beverage consumption delays alveolar bone healing: a histometric study in rats.

PubMed

Teófilo, Juliana Mazzonetto; Leonel, Daniel Vilela; Lamano, Teresa

2010-01-01

Epidemiological studies have suggested that cola beverage consumption may affect bone metabolism and increase bone fracture risk. Experimental evidence linking cola beverage consumption to deleterious effects on bone is lacking. Herein, we investigated whether cola beverage consumption from weaning to early puberty delays the rate of reparative bone formation inside the socket of an extracted tooth in rats. Twenty male Wistar rats received cola beverage (cola group) or tap water (control group) ad libitum from the age of 23 days until tooth extraction at 42 days and euthanasia 2 and 3 weeks later. The neoformed bone volume inside the alveolar socket was estimated in semi-serial longitudinal sections using a quantitative differential point-counting method. Histological examination suggested a decrease in the osteogenic process within the tooth sockets of rats from both cola groups, which had thinner and sparser new bone trabeculae. Histometric data confirmed that alveolar bone healing was significantly delayed in cola-fed rats at three weeks after tooth extraction (ANOVA, p = 0.0006, followed by Tukey's test, p < 0.01). Although the results of studies in rats cannot be extrapolated directly to human clinical dentistry, the present study provides evidence that cola beverage consumption negatively affect maxillary bone formation.

RNA-Sequencing Analyses Demonstrate the Involvement of Canonical Transient Receptor Potential Channels in Rat Tooth Germ Development

PubMed Central

Yang, Jun; Cai, Wenping; Lu, Xi; Liu, Shangfeng; Zhao, Shouliang

2017-01-01

Tooth development depends on multiple molecular interactions between the dental epithelium and mesenchyme, which are derived from ectodermal and ectomesenchymal cells, respectively. We report on a systematic RNA sequencing analysis of transcriptional expression levels from the bud to hard tissue formation stages of rat tooth germ development. We found that GNAO1, ENO1, EFNB1, CALM1, SIAH2, ATP6V0A1, KDELR2, GTPBP1, POLR2C, SORT1, and members of the canonical transient receptor potential (TRPC) channel family are involved in tooth germ development. Furthermore, Cell Counting Kit 8 (CCK8) and Transwell migration assays were performed to explore the effects of these differentially expressed genes (DEGs) on the proliferation and migration of dental pulp stem cells. Immunostaining revealed that TRPC channels are expressed at varying levels during odontogenesis. The identified genes represent novel candidates that are likely to be vital for rat tooth germ development. Together, the results provide a valuable resource to elucidate the gene regulatory mechanisms underlying mammalian tooth germ development. PMID:28706494

Effects of calcitonin on orthodontic tooth movement and associated root resorption in rats.

PubMed

Guan, Ling; Lin, Suai; Yan, Weijun; Chen, Lei; Wang, Xiaofeng

2017-11-01

Our main aim was to evaluate the effects of calcitonin (CT) on orthodontic tooth movement (OTM) and orthodontic root resorption in a rat model. Eighty male Wistar rats were randomly divided into five groups. Rats in the negative control group were not given any appliances or injections. All the remaining rats were used to establish a model of OTM. The positive control group were then injected with normal saline, while rats in the three experimental groups were injected with 0.2 IU, 1 IU or 5 IU/kg/day CT. Nickel-titanium closed-coil springs were used to deliver an initial 50 g mesial force to the left maxillary first molar for 14 days in rats in the positive control group and the experimental groups. Each group was randomly subdivided into two groups, one for analysis of tooth movement, tissue changes and tartrate-resistant acid phosphatase (TRAP)-positive cells in alveolar bone, the other to examine root resorption by scanning electron microscopy. The OTM distance, the number of force-induced osteoclasts and root resorption areas were significantly decreased in CT-injected rats in a dose-dependent manner. Administration of CT reduces the root resorption area and may therefore be effective as a novel adjunctive orthodontic approach to diminish undesired tooth movement via enhancing anchorage or preventing relapse after OTM.

Wnt signaling during tooth replacement in zebrafish (Danio rerio): pitfalls and perspectives

PubMed Central

Huysseune, Ann; Soenens, Mieke; Elderweirdt, Fien

2014-01-01

The canonical (β-catenin dependent) Wnt signaling pathway has emerged as a likely candidate for regulating tooth replacement in continuously renewing dentitions. So far, the involvement of canonical Wnt signaling has been experimentally demonstrated predominantly in amniotes. These studies tend to show stimulation of tooth formation by activation of the Wnt pathway, and inhibition of tooth formation when blocking the pathway. Here, we report a strong and dynamic expression of the soluble Wnt inhibitor dickkopf1 (dkk1) in developing zebrafish (Danio rerio) tooth germs, suggesting an active repression of Wnt signaling during morphogenesis and cytodifferentiation of a tooth, and derepression of Wnt signaling during start of replacement tooth formation. To further analyse the role of Wnt signaling, we used different gain-of-function approaches. These yielded disjunct results, yet none of them indicating enhanced tooth replacement. Thus, masterblind (mbl) mutants, defective in axin1, mimic overexpression of Wnt, but display a normally patterned dentition in which teeth are replaced at the appropriate times and positions. Activating the pathway with LiCl had variable outcomes, either resulting in the absence, or the delayed formation, of first-generation teeth, or yielding a regular dentition with normal replacement, but no supernumerary teeth or accelerated tooth replacement. The failure so far to influence tooth replacement in the zebrafish by perturbing Wnt signaling is discussed in the light of (i) potential technical pitfalls related to dose- or time-dependency, (ii) the complexity of the canonical Wnt pathway, and (iii) species-specific differences in the nature and activity of pathway components. Finally, we emphasize the importance of in-depth knowledge of the wild-type pattern for reliable interpretations. It is hoped that our analysis can be inspiring to critically assess and elucidate the role of Wnt signaling in tooth development in polyphyodonts. PMID:25339911

Effects of Carbonated Soft Drink Consumption on Orthodontic Tooth Movements in Rats

PubMed Central

Aghili, Hossein Agha; Hoseini, Seyed Mohammad; Yassaei, Soghra; Fatahi meybodi, Seyed Amirreza; Zaeim, Mohammad Hosein Toudeh; Moghadam, Mahdjoubeh Goldani

2014-01-01

Objective: The aim of this animal study was to evaluate the possible effects of Carbonated Soft Drink consumption on the rate of orthodontic tooth movement in rats. Materials and Methods: Thirty-six adult male Sprague-Dawley rats were randomly divided into two experimental groups and one control group. In the experimental groups (A&B), the water in the dietary regimen was replaced with soft drinks (Fanta® in group A and Cola® in group B) two weeks before placement of orthodontic appliances. Then 5-mm nickel-titanium closed-coil springs were placed between the maxillary right first molars and first incisors under general anesthesia. This regimen continued for two weeks more and animals drank soft drink ad libitum. At the end of the experimental period, the rats were sacrificed, and interproximal tooth movements were measured. Results: The mean amounts of tooth movement were 0.19mm in group A, 0.22mm in group B and 0.37mm in group C. Statistical analysis with analysis of variance (ANOVA) test showed significant differences between all groups. The least movement occurred in group A that had received Fanta® drink. Conclusion: CSDs consumption decreases the rate of orthodontic tooth movement. The role of soft drinks in decreasing tooth movement might be related to its effects on bone metabolism. PMID:24910686

Dual odontogenic origins develop at the early stage of rat maxillary incisor development.

PubMed

Kriangkrai, Rungarun; Iseki, Sachiko; Eto, Kazuhiro; Chareonvit, Suconta

2006-03-01

Developmental process of rat maxillary incisor has been studied through histological analysis and investigation of tooth-related gene expression patterns at initial tooth development. The tooth-related genes studied here are fibroblast growth factor-8 (Fgf-8), pituitary homeobox gene-2 (Pitx-2), sonic hedgehog (Shh), muscle segment homeobox-1 (Msx-1), paired box-9 (Pax-9) and bone morphogenetic protein-4 (Bmp-4). The genes are expressed in oral epithelium and/or ectomesenchyme at the stage of epithelial thickening to the early bud stage of tooth development. Both the histological observation and tooth-related gene expression patterns during early stage of maxillary incisor development demonstrate that dual odontogenic origins aligned medio-laterally in the medial nasal process develop, subsequently only single functional maxillary incisor dental placode forms. The cascade of tooth-related gene expression patterns in rat maxillary incisor studied here is quite similar to those of the previous studies in mouse mandibular molar, even though the origins of oral epithelium and ectomesenchyme involved in development of maxillary incisor and mandibular molar are different. Thus, we conclude that maxillary incisor and mandibular molar share a similar signaling control of Fgf-8, Pitx-2, Shh, Msx-1, Pax-9 and Bmp-4 genes at the stage of oral epithelial thickening to the early bud stage of tooth development.

Sodium hyaluronate accelerates the healing process in tooth sockets of rats.

PubMed

Mendes, Renato M; Silva, Gerluza A B; Lima, Miguel F; Calliari, Marcelo V; Almeida, Alvair P; Alves, José B; Ferreira, Anderson J

2008-12-01

In this study we evaluated the effects of sodium hyaluronate (HY) in the healing process of tooth sockets of rats. Immediately after the extraction of the upper first molars of male Holtzman rats, right sockets were treated with 1% HY gel (approximately 0.1 ml), while left sockets were used as control (blood clot). The animals were sacrificed at 2, 7, and 21 days after tooth extraction and upper maxillaries processed for histological and morphometric analysis of the apical and medium thirds of the sockets. Carbopol, an inert gel, was used to evaluate the mechanical effect of gel injection into sockets. Expression of bone morphogenetic protein-2 (BMP-2) and osteopontin (OPN) was determined by immunohistochemistry at 1, 2, 3, 4, 5, and 7 days after tooth extraction. Histological analysis showed that HY treatment induced earlier trabecular bone deposition resulting in a bone matrix more organized at 7 and 21 days after tooth extraction. Also, HY elicited significant increase in the amount of bone trabeculaes at 7 and 21 days after tooth extraction (percentage of trabecular bone area at 7 days: 13.21+/-4.66% vs. 2.58+/-1.36% in the apical third of control sockets) and in the vessels counting at 7 days. Conversely, the number of cell nuclei was decreased in HY-treated sockets. Additionally, expression of BMP-2 and OPN was enhanced in HY-treated sockets compared with control sockets. These findings suggest that HY accelerates the healing process in tooth sockets of rats stimulating the expression of osteogenic proteins.

Daughters of the Enamel Organ: Development, Fate, and Function of the Stratum Intermedium, Stellate Reticulum, and Outer Enamel Epithelium

PubMed Central

Liu, Hui; Yan, Xiulin; Pandya, Mirali; Luan, Xianghong

2016-01-01

The tooth enamel organ (EO) is a complex epithelial cell assembly involved in multiple aspects of tooth development, including amelogenesis. The present study focuses on the role of the nonameloblast layers of the EO, the stratum intermedium, the stellate reticulum, and the outer enamel epithelium (OEE). The secretory stage stratum intermedium was distinguished by p63-positive epithelial stem cell marks, highly specific alkaline phosphatase labeling, as well as multiple desmosomes and gap junctions. At the location of the presecretory stage stellate reticulum, the pre-eruption EO prominently featured the papillary layer (PL) as a keratin immunopositive network of epithelial strands between tooth crowns and oral epithelium. PL cell strands contained numerous p63-positive epithelial stem cells, while BrdU proliferative cells were detected at the outer boundaries of the PL, suggesting that the stellate reticulum/PL epithelial cell sheath proliferated to facilitate an epithelial seal during tooth eruption. Comparative histology studies demonstrated continuity between the OEE and the general lamina of continuous tooth replacement in reptiles, and the outer layer of Hertwig's epithelial root sheath in humans, implicating the OEE as the formative layer for continuous tooth replacement and tooth root extension. Cell fate studies in organ culture verified that the cervical portion of the mouse molar EO gave rise to Malassez rest-like cell islands. Together, these studies indicate that the nonameloblast layers of the EO play multiple roles during odontogenesis, including the maintenance of several p63-positive stem cell reservoirs, a role during tooth root morphogenesis and tooth succession, a stabilizing function for the ameloblast layer, the facilitation of ion transport from the EO capillaries to the enamel layer, as well as safe and seamless tooth eruption. PMID:27611344

Daughters of the Enamel Organ: Development, Fate, and Function of the Stratum Intermedium, Stellate Reticulum, and Outer Enamel Epithelium.

PubMed

Liu, Hui; Yan, Xiulin; Pandya, Mirali; Luan, Xianghong; Diekwisch, Thomas G H

2016-09-09

The tooth enamel organ (EO) is a complex epithelial cell assembly involved in multiple aspects of tooth development, including amelogenesis. The present study focuses on the role of the nonameloblast layers of the EO, the stratum intermedium, the stellate reticulum, and the outer enamel epithelium (OEE). The secretory stage stratum intermedium was distinguished by p63-positive epithelial stem cell marks, highly specific alkaline phosphatase labeling, as well as multiple desmosomes and gap junctions. At the location of the presecretory stage stellate reticulum, the pre-eruption EO prominently featured the papillary layer (PL) as a keratin immunopositive network of epithelial strands between tooth crowns and oral epithelium. PL cell strands contained numerous p63-positive epithelial stem cells, while BrdU proliferative cells were detected at the outer boundaries of the PL, suggesting that the stellate reticulum/PL epithelial cell sheath proliferated to facilitate an epithelial seal during tooth eruption. Comparative histology studies demonstrated continuity between the OEE and the general lamina of continuous tooth replacement in reptiles, and the outer layer of Hertwig's epithelial root sheath in humans, implicating the OEE as the formative layer for continuous tooth replacement and tooth root extension. Cell fate studies in organ culture verified that the cervical portion of the mouse molar EO gave rise to Malassez rest-like cell islands. Together, these studies indicate that the nonameloblast layers of the EO play multiple roles during odontogenesis, including the maintenance of several p63-positive stem cell reservoirs, a role during tooth root morphogenesis and tooth succession, a stabilizing function for the ameloblast layer, the facilitation of ion transport from the EO capillaries to the enamel layer, as well as safe and seamless tooth eruption.

The impact of gape on the performance of the skull in chisel-tooth digging and scratch digging mole-rats (Rodentia: Bathyergidae).

PubMed

McIntosh, Andrew F; Cox, Philip G

2016-10-01

The African mole-rats (Bathyergidae) are a family of rodents highly adapted for life underground. Previous research has shown that chisel-tooth digging mole-rats (which use their incisors to dig burrows) are clearly distinguishable from scratch diggers (which only use the forelimbs to tunnel) on the basis of morphology of the skull, and that the differences are linked to the production of high bite forces and wide gapes. We hypothesized that the skull of a chisel-tooth digging mole-rat would perform better at wider gapes than that of a scratch digging mole-rat during incisor biting. To test this hypothesis, we created finite-element models of the cranium of the scratch digging Bathyergus suillus and the chisel-tooth digging Fukomys mechowii , and loaded them to simulate incisor bites at different gapes. Muscle loads were scaled such that the ratio of force to surface area was the same in both models. We measured three performance variables: overall stress across the cranium, mechanical efficiency of biting and degree of deformation across the skull. The Fukomys model had a more efficient incisor bite at all gapes, despite having greater average stress across the skull. In addition, the Fukomys model deformed less at wider gapes, whereas the Bathyergus model deformed less at narrower gapes. These properties of the cranial morphology of Fukomys and Bathyergus are congruent with their respective chisel-tooth and scratch digging behaviours and, all other factors being equal, would enable the more efficient production of bite force at wider gapes in Fukomys . However, in vivo measurements of muscle forces and activation patterns are needed to fully understand the complex biomechanics of tooth digging.

The impact of gape on the performance of the skull in chisel-tooth digging and scratch digging mole-rats (Rodentia: Bathyergidae)

NASA Astrophysics Data System (ADS)

McIntosh, Andrew F.; Cox, Philip G.

2016-10-01

The African mole-rats (Bathyergidae) are a family of rodents highly adapted for life underground. Previous research has shown that chisel-tooth digging mole-rats (which use their incisors to dig burrows) are clearly distinguishable from scratch diggers (which only use the forelimbs to tunnel) on the basis of morphology of the skull, and that the differences are linked to the production of high bite forces and wide gapes. We hypothesized that the skull of a chisel-tooth digging mole-rat would perform better at wider gapes than that of a scratch digging mole-rat during incisor biting. To test this hypothesis, we created finite-element models of the cranium of the scratch digging Bathyergus suillus and the chisel-tooth digging Fukomys mechowii, and loaded them to simulate incisor bites at different gapes. Muscle loads were scaled such that the ratio of force to surface area was the same in both models. We measured three performance variables: overall stress across the cranium, mechanical efficiency of biting and degree of deformation across the skull. The Fukomys model had a more efficient incisor bite at all gapes, despite having greater average stress across the skull. In addition, the Fukomys model deformed less at wider gapes, whereas the Bathyergus model deformed less at narrower gapes. These properties of the cranial morphology of Fukomys and Bathyergus are congruent with their respective chisel-tooth and scratch digging behaviours and, all other factors being equal, would enable the more efficient production of bite force at wider gapes in Fukomys. However, in vivo measurements of muscle forces and activation patterns are needed to fully understand the complex biomechanics of tooth digging.

The role of periodontal ASIC3 in orofacial pain induced by experimental tooth movement in rats.

PubMed

Gao, Meiya; Long, Hu; Ma, Wenqiang; Liao, Lina; Yang, Xin; Zhou, Yang; Shan, Di; Huang, Renhuan; Jian, Fan; Wang, Yan; Lai, Wenli

2016-12-01

This study aimed to clarify the roles of Acid-sensing ion channel 3 (ASIC3) in orofacial pain following experimental tooth movement. Sixty male Sprague-Dawley rats were divided into the experimental group (40g, n = 30) and the sham group (0g, n = 30). Closed coil springs were ligated between maxillary incisor and molars to achieve experimental tooth movement. Rat grimace scale (RGS) scores were assessed at 0, 1, 3, 5, 7, and 14 days after the placement of the springs. ASIC3 immunostaining was performed and the expression levels of ASIC3 were measured through integrated optical density/area in Image-Pro Plus 6.0. Moreover, 18 rats were divided into APETx2 group (n = 6), amiloride group (n = 6), and vehicle group (n = 6), and RGS scores were obtained compared among them to verify the roles of ASIC3 in orofacial pain following tooth movement. ASIC3 expression levels became significantly higher in the experimental group than in sham group on 1, 3, and 5 days and became similar on 7 and 14 days. Pain levels (RGS scores) increased in both groups and were significantly higher in the experimental group on 1, 3, 5, and 7 days and were similar on 14 days. Periodontal ASIC3 expression levels were correlated with orofacial pain levels following experimental tooth movement. Periodontal administrations of ASIC3 antagonists (APETx2 and amiloride) could alleviate pain. This study needs to be better evidenced by RNA interference of ASIC3 in periodontal tissues in rats following experimental tooth movement. Moreover, we hope further studies would concentrate on the pain perception of ASIC3 knockout (ASIC3 -/- ) mice. Our results suggest that periodontal ASIC3 plays an important role in orofacial pain induced by experimental tooth movement. © The Author 2015. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.

The effect of fluoride on enamel and dentin formation in the uremic rat incisor.

PubMed

Lyaruu, Donacian M; Bronckers, Antonius L J J; Santos, Fernando; Mathias, Robert; DenBesten, Pamela

2008-11-01

Renal impairment in children is associated with tooth defects that include enamel pitting and hypoplasia. However, the specific effects of uremia on tooth formation are not known. In this study, we used rat mandibular incisors, which continuously erupt and contain all stages of tooth formation, to characterize the effects of uremia on tooth formation. We also tested the hypothesis that uremia aggravates the fluoride (F)-induced changes in developing teeth. Rats were subjected to a two-stage 5/6 nephrectomy or sham operation and then exposed to 0 (control) or 50 ppm NaF in drinking water for 14 days. The effects of these treatments on food intake, body growth rate, and biochemical serum parameters for renal function and calcium metabolism were monitored. Nephrectomy reduced food intake and weight gain. Intake of F by nephrectomized rats increased plasma F levels twofold and further decreased food intake and body weight gain. Uremia affected formation of dentin and enamel and was more extensive than the effect of F alone. Uremia also significantly increased predentin width and induced deposition of large amounts of osteodentin-like matrix-containing cells in the pulp chamber. In enamel formation, the cells most sensitive to uremia were the transitional-stage ameloblasts. These data demonstrate that intake of F by rats with reduced renal function impairs F clearance from the plasma and aggravates the already negative effects of uremia on incisor tooth development.

The Effects of Inflammatory Tooth Pain on Anxiety in Adult Male Rats

PubMed Central

Raoof, Maryam; Ebrahimnejad, Hamed; Abbasnejad, Mehdi; Amirkhosravi, Ladan; Raoof, Ramin; Esmaeili Mahani, Saeed; Ramazani, Mohsen; Shokouhinejad, Noushin; Khoshkhounejad, Mehrfam

2016-01-01

Introduction: This study aimed to examine the effects of induced inflammatory tooth pain on anxiety level in adult male rats. Methods: The mandibular incisors of 56 adult male rats were cut off and prefabricated crowns were fixed on the teeth. Formalin and capsaicin were injected intradentally to induce inflammatory tooth pain. Diazepam treated group received diazepam 30 minutes before intradental injection. The anxiety-related behavior was evaluated with elevated plus maze test. Results: Intradental application of chemical noxious stimuli, capsaicin and formalin, significantly affected nociceptive behaviors (P<0.001). Capsaicin (P<0.001) and formalin (P<0.01) significantly increased the anxiety levels in rats by decrease in the duration of time spent in open arm and increase in the duration of time spent in closed arm. Rats that received capsaicin made fewer open arm entries compared to the control animals (P<0.05). Capsaicin (P<0.001) and formalin (P<0.01) treated rats showed more stretch attend postures compared to the control and sham operated animals. In diazepampretreated rats, capsaicin induced algesic effect was prevented (P<0.001). Conclusion: Inflammatory pulpal pain has anxiogenic effect on rats, whereas diazepam premedication showed both anxiolytic and pain reducing effects. PMID:27563419

Spatially restricted dental regeneration drives pufferfish beak development

PubMed Central

Thiery, Alexandre P.; Shono, Takanori; Kurokawa, Daisuke; Britz, Ralf; Johanson, Zerina

2017-01-01

Vertebrate dentitions are extraordinarily diverse in both morphology and regenerative capacity. The teleost order Tetraodontiformes exhibits an exceptional array of novel dental morphologies, epitomized by constrained beak-like dentitions in several families, i.e., porcupinefishes, three-toothed pufferfishes, ocean sunfishes, and pufferfishes. Modification of tooth replacement within these groups leads to the progressive accumulation of tooth generations, underlying the structure of their beaks. We focus on the dentition of the pufferfish (Tetraodontidae) because of its distinct dental morphology. This complex dentition develops as a result of (i) a reduction in the number of tooth positions from seven to one per quadrant during the transition from first to second tooth generations and (ii) a dramatic shift in tooth morphogenesis following the development of the first-generation teeth, leading to the elongation of dental units along the jaw. Gene expression and 1,1′-Dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate (DiI) lineage tracing reveal a putative dental epithelial progenitor niche, suggesting a highly conserved mechanism for tooth regeneration despite the development of a unique dentition. MicroCT analysis reveals restricted labial openings in the beak, through which the dental epithelium (lamina) invades the cavity of the highly mineralized beak. Reduction in the number of replacement tooth positions coincides with the development of only four labial openings in the pufferfish beak, restricting connection of the oral epithelium to the dental cavity. Our data suggest the spatial restriction of dental regeneration, coupled with the unique extension of the replacement dental units throughout the jaw, are primary contributors to the evolution and development of this unique beak-like dentition. PMID:28507130

Effect of cyclical forces on the periodontal ligament and alveolar bone remodeling during orthodontic tooth movement

PubMed Central

Kalajzic, Zana; Peluso, Elizabeth Blake; Utreja, Achint; Dyment, Nathaniel; Nihara, Jun; Xu, Manshan; Chen, Jing; Uribe, Flavio; Wadhwa, Sunil

2014-01-01

Objective To investigate the effect of externally applied cyclical (vibratory) forces on the rate of tooth movement, the structural integrity of the periodontal ligament, and alveolar bone remodeling. Methods Twenty-six female Sprague-Dawley rats (7 weeks old) were divided into four groups: CTRL (unloaded), VBO (molars receiving a vibratory stimulus only), TMO (molars receiving an orthodontic spring only), and TMO+VB (molars receiving an orthodontic spring and the additional vibratory stimulus). In TMO and TMO+VB groups, the rat first molars were moved mesially for 2 weeks using Nickel-Titanium coil spring delivering 25 g of force. In VBO and TMO+VB groups, cyclical forces at 0.4 N and 30 Hz were applied occlusally twice a week for 10 minutes. Microfocus X-ray computed tomography analysis and tooth movement measurements were performed on the dissected rat maxillae. Tartrate-resistant acid phosphatase staining and collagen fiber assessment were performed on histological sections. Results Cyclical forces significantly inhibited the amount of tooth movement. Histological analysis showed marked disorganization of the collagen fibril structure of the periodontal ligament during tooth movement. Tooth movement caused a significant increase in osteoclast parameters on the compression side of alveolar bone and a significant decrease in bone volume fraction in the molar region compared to controls. Conclusions Tooth movement was significantly inhibited by application of cyclical forces. PMID:23937517

Anabolic steroid abuse and tooth size-arch dimensions in the rat.

PubMed

Barrett, R L; Harris, E F; Tolley, E A; Nutting, D F

1993-01-01

Anabolic steroids are misused by adolescents and adults to increase muscle mass and improve appearance and athletic performance. Since anabolics strongly enhance protein synthesis, it was speculated that alterations in tooth size and arch length could occur. This study quantified the effects of the anabolic steroid nandrolone phenpropionate on these parameters in a rat model. The steroid significantly increased mandibular arch length. No difference in mesiodistal dimensions of the molars occurred. In consequence, the increased arch dimensions combined with unaltered tooth size may result in dental spacing and/or other malocclusions.

Increasing the amount of corticotomy does not affect orthodontic tooth movement or root resorption, but accelerates alveolar bone resorption in rats.

PubMed

Kurohama, Takeshi; Hotokezaka, Hitoshi; Hashimoto, Megumi; Tajima, Takako; Arita, Kotaro; Kondo, Takanobu; Ino, Airi; Yoshida, Noriaki

2017-06-01

The purpose of this study was to evaluate the relationships among the volume of bone cut during corticotomy, amount of tooth movement, volume of root resorption, and volume of the resultant alveolar bone resorption after tooth movement. Ten-week-old female Wistar rats were distributed into the corticotomy groups and a control group that underwent sham corticotomy. Two experiments employing two different orthodontic forces (10 or 25g) and experimental periods (14 or 21 days) were performed. The volumes of the bone cut by corticotomy were 0.1, 1.0, and 1.7mm3 in the 25g groups, and 1.0 and 1.7mm3 in the 10g groups. Nickel-titanium closed-coil springs were set on the maxillary left first molars to induce mesial movement. After orthodontic tooth movement, the amount of tooth movement, volume of root resorption, and volume of alveolar bone resorption were measured. Despite differences in the volume of bone cut among the different corticotomy groups, there were not significant differences in the amount of tooth movement and volume of root resorption between the control group and any of the corticotomy groups. However, higher volume of bone cut during corticotomy was significantly related to the decreased alveolar bone volume-in particular, to the reduced height of the alveolar bone crest after tooth movement. The volume of the alveolar bone cut during corticotomy does not affect tooth movement or root resorption in 10-week-old female Wistar rats; however, it may increase alveolar bone loss after tooth movement. © The Author 2016. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com

Effect of Atorvastatin on Orthodontic Tooth Movement in Male Wistar Rats

PubMed Central

MirHashemi, Amir Hossein; Afshari, Maryam; Alaeddini, Mojgan; Etemad-Moghadam, Shahroo; Dehpour, Ahmadreza; Sheikhzade, Sedigheh; Akhoundi, Mohammad Sadegh Ahmad

2013-01-01

Objectives: Statins are used as cholesterol-lowering drugs by many patients and have been recently shown to affect bone metabolism. The aim of this study was to determine the effect of atorvastatinon on orthodontic tooth movement (OTM) in rats. Materials and Methods: Thirty-six adult male Sprague-Dawley rats were randomly divided into three groups of 12 samples each. Group A, served as control with no medication while groups B and C received a daily gavage of carboxymethyl cellulose (CMC) as vehicle and atorvastatin (5 mg/kg) as test substance, respectively. In all three groups, 6mm nickel-titanium closed-coil springs were ligated between the maxillary incisors and first left molars to deliver an initial force of 60g. Tooth movement was measured following sacrifice, 21 days after appliance insertion. Root resorption, PDL width and osteoclast number were histologically evaluated and compared between the groups. Results: The mean amount of tooth movement was 0.62 mm in group A, 0.59 mm in group B and 0.38 mm in group C. OTM reduction following administration of atorvastatin was statistically significant (p<0.05), but there was no significant difference in the studied histologic variables among the three groups (p>0.05). Conclusion: According to the results obtained in the current study, atorvastatin appears to reduce tooth movement in rats; however its effect on osteoclasts, especially osteoclastic function, requires further investigation. PMID:24910664

Coordination of Cellular Dynamics Contributes to Tooth Epithelium Deformations

PubMed Central

Morita, Ritsuko; Kihira, Miho; Nakatsu, Yousuke; Nomoto, Yohei; Ogawa, Miho; Ohashi, Kazumasa; Mizuno, Kensaku; Tachikawa, Tetsuhiko; Ishimoto, Yukitaka; Morishita, Yoshihiro; Tsuji, Takashi

2016-01-01

The morphologies of ectodermal organs are shaped by appropriate combinations of several deformation modes, such as invagination and anisotropic tissue elongation. However, how multicellular dynamics are coordinated during deformation processes remains to be elucidated. Here, we developed a four-dimensional (4D) analysis system for tracking cell movement and division at a single-cell resolution in developing tooth epithelium. The expression patterns of a Fucci probe clarified the region- and stage-specific cell cycle patterns within the tooth germ, which were in good agreement with the pattern of the volume growth rate estimated from tissue-level deformation analysis. Cellular motility was higher in the regions with higher growth rates, while the mitotic orientation was significantly biased along the direction of tissue elongation in the epithelium. Further, these spatio-temporal patterns of cellular dynamics and tissue-level deformation were highly correlated with that of the activity of cofilin, which is an actin depolymerization factor, suggesting that the coordination of cellular dynamics via actin remodeling plays an important role in tooth epithelial morphogenesis. Our system enhances the understanding of how cellular behaviors are coordinated during ectodermal organogenesis, which cannot be observed from histological analyses. PMID:27588418

Low-level laser therapy stimulates bone metabolism and inhibits root resorption during tooth movement in a rodent model.

PubMed

Suzuki, Selly Sayuri; Garcez, Aguinaldo Silva; Suzuki, Hideo; Ervolino, Edilson; Moon, Won; Ribeiro, Martha Simões

2016-12-01

This study evaluated the biological effects of low-level laser therapy (LLLT) on bone remodeling, tooth displacement and root resorption, occurred during the orthodontic tooth movement. Upper first molars of a total of sixty-eight male rats were subjected to orthodontic tooth movement and euthanized on days 3, 6, 9, 14 and 21 days and divided as negative control, control and LLLT group. Tooth displacement and histomorphometric analysis were performed in all animals; scanning electron microscopy analysis was done on days 3, 6 and 9, as well as the immunohistochemistry analysis of RANKL/OPG and TRAP markers. Volumetric changes in alveolar bone were analyzed using MicroCT images on days 14 and 21. LLLT influenced bone resorption by increasing the number of TRAP-positive osteoclasts and the RANKL expression at the compression side. This resulted in less alveolar bone and hyalinization areas on days 6, 9 and 14. LLLT also induced less bone volume and density, facilitating significant acceleration of tooth movement and potential reduction in root resorption besides stimulating bone formation at the tension side by enhancing OPG expression, increasing trabecular thickness and bone volume on day 21. Taken together, our results indicate that LLLT can stimulate bone remodeling reducing root resorption in a rat model. LLLT improves tooth movement via bone formation and bone resorption in a rat model. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tooth development in vitro in two teleost fish, the cichlid Hemichromis bimaculatus and the cyprinid Danio rerio.

PubMed

Van der Heyden, C; Allizard, F; Sire, J-Y; Huysseune, A

2005-09-01

A technique for organotypic in vitro culture with serum-free medium was tested for its appropriateness to mimic normal odontogenesis in the cichlid fish Hemichromis bimaculatus and the zebrafish Danio rerio. Serial semithin sections were observed by light microscopy to collect data on tooth patterning and transmission electron microscopy was used to compare cellular and extracellular features of tooth germs developing in vitro with the situation in vivo. Head explants of H. bimaculatus from 120 h post-fertilization (hPF) to 8.5 days post-fertilization (dPF) and of zebrafish from 45 hPF to 79 hPF and adults kept in culture for 3, 4 or 7 days revealed that tooth germs developed in vitro from explants in which the buccal or pharyngeal epithelium was apparently undifferentiated and, when present at the time of explantation, they continued their development up to a stage of attachment. In addition, the medium allowed the morphogenesis and cytodifferentiation of the tooth germs similar to that observed in vivo and the establishment of a dental pattern (place and order of tooth appearance and of attachment) that mimicked that in vivo. Organotypic culture in serum-free conditions thus provides us with the means of studying epithelial-mesenchymal interactions during tooth development in teleost fish and of analysing the genetic control of either mandibular or pharyngeal tooth development and replacement in these polyphyodont species. Importantly, it allows heads from embryonically lethal (zebrafish) mutants or from early lethal knockdown experiments to develop beyond the point at which the embryos normally die. Such organotypic culture in serum-free conditions could therefore become a powerful tool in developmental studies and open new perspectives for craniofacial research.

Utility of 18F-fluorodeoxy glucose and 18F-sodium fluoride positron emission tomography/computed tomography in the diagnosis of medication-related osteonecrosis of the jaw: A preclinical study in a rat model.

PubMed

Kim, Yemi; Lee, Ho-Young; Yoon, Hai-Jeon; Kim, Bom Sahn

2016-04-01

The aim of this study was to determine the clinical utility of positron emission tomography/computed tomography (PET/CT) using 18F-FDG and 18F-NaF for the diagnosis of osteonecrosis of the jaw (ONJ), by observing characteristics in rat models treated with zoledronic acid (ZA) and/or dexamethasone (DX) followed by tooth extraction. A total of 48 rats were divided randomly into four groups: Group 1, rats treated with ZA and DX; Group 2, rats treated with ZA; Group 3, rats treated with DX; and Group 4, rats treated with vehicle as normal controls. They underwent examinations with both 18F-FDG and 18F-NaF PET/CT at 4 weeks prior to tooth extraction (baseline) and 4 weeks after tooth extraction. Rats were then sacrificed to evaluate the histological incidence and characteristics of ONJ. Histological and radiological characteristics of all groups were compared to assess the effects of medication and tooth extraction. Baseline PET/CT studies using 18F-FDG and 18F-NaF showed no difference in uptake among the groups. However, 18F-FDG PET/CT performed at 4 weeks after tooth extraction showed increased glucose metabolism at the extraction site in both the ZA/DX and the ZA-only groups compared with that in the vehicle-treated group, in accordance with the higher incidence of histological ONJ (p < 0.05, respectively). 18F-NaF PET/CT performed at 4 weeks after tooth extraction showed decreased bone uptake in the extraction site in the ZA/DX, ZA, and DX groups versus the vehicle group (all p < 0.05), but this was not correlated with the incidence of histological ONJ. The incidence of ONJ was highest in the ZA/DX group (66.7%), followed by the ZA group, both of which were significantly higher than in the DX and vehicle groups (both p < 0.05). 18F-FDG PET/CT as an inflammatory marker appeared to be a more appropriate imaging modality than 18F-NaF PET/CT in diagnosing ONJ in a rat model including a ZA/DX group. However, the decreased bone remodeling tendency highlighted by 18F-NaF PET/CT may be an indicator of a possible risk of ONJ before the onset of clinical signs and symptoms. Copyright © 2016 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Effect of fluoxetine on induced tooth movement in rats.

PubMed

Franzon Frigotto, Giovana Carla; Miranda de Araujo, Cristiano; Guariza Filho, Odilon; Tanaka, Orlando Motohiro; Batista Rodrigues Johann, Aline Cristina; Camargoa, Elisa Souza

2015-09-01

Fluoxetine is a widely used antidepressant. Its various effects on bone mineral density are well described. The aim of this study was to evaluate the effect of fluoxetine on induced tooth movement. Seventy-two Wistar rats were divided into 3 groups: M (n = 24; 0.9% saline solution and induced tooth movement), FM (n = 24; fluoxetine, 10 mg/kg, and induced tooth movement), and F (n = 24; fluoxetine, 10 mg/kg only). After 30 days of daily saline solution or fluoxetine administration, an orthodontic appliance (30 cN) was used to displace the first molar mesially in groups M and FM. The animals were killed 3, 7, and 14 days after placement of the orthodontic appliances. The animals in group F did not receive induced tooth movement but were killed at the same times. We evaluated tooth movement rates, collagen neoformation rates by polarization microscopy, numbers of osteoclast by tartrate-resistant acid phosphatase, and trabecular bone modeling by microcomputed tomography of the femur. The tooth movement rates were similar in groups M and FM at all studied time points (P >0.05). The rate of newly formed collagen had a reverse pattern in groups M and FM, but the difference was not statistically significant (P >0.05). There were significantly more osteoclasts in group FM than in group F on day 3 (P <0.01). The trabecular spacing was significantly larger in group F compared with group M on day 14 (P <0.05). Fluoxetine did not interfere with induced tooth movement or trabecular bone in rats. Copyright © 2015 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Initiation of teeth from the dental lamina in the ferret.

PubMed

Jussila, Maria; Crespo Yanez, Xenia; Thesleff, Irma

2014-01-01

Mammalian tooth development is characterized by formation of primary teeth that belong to different tooth classes and are later replaced by a single set of permanent teeth. The first primary teeth are initiated from the primary dental lamina, and the replacement teeth from the successional dental lamina at the lingual side of the primary teeth. An interdental lamina connects the primary tooth germs together. Most mammalian tooth development research is done on mouse, which does not have teeth in all tooth classes, does not replace its teeth, and does not develop an interdental lamina. We have used the ferret (Mustela putorius furo) as a model animal to elucidate the morphological changes and gene expression during the development of the interdental lamina and the initiation of primary teeth. In addition we have analyzed cell-cell signaling taking place in the interdental lamina as well as in the successional lamina during tooth replacement. By 3D reconstructions of serial histological sections we observed that the morphogenesis of the interdental lamina and the primary teeth are intimately linked. Expression of Pitx2 and Foxi3 in the interdental lamina indicates that it has odontogenic identity, and there is active signaling taking place in the interdental lamina. Bmp4 is coexpressed with the stem cell factor Sox2 at its lingual aspect suggesting that the interdental lamina may retain competence for tooth initiation. We show that when tooth replacement is initiated there is Wnt pathway activity in the budding successional lamina and adjacent mesenchyme but no active Fgf or Eda signaling. Genes associated with human tooth replacement phenotypes, including Runx2 and Il11rα, are mostly expressed in the mesenchyme around the successional lamina in the ferret. Our results highlight the importance of the dental lamina in the mammalian tooth development during the initiation of both primary and replacement teeth. Copyright © 2013 International Society of Differentiation. Published by Elsevier B.V. All rights reserved.

Effect of a static magnetic field on orthodontic tooth movement in the rat.

PubMed

Tengku, B S; Joseph, B K; Harbrow, D; Taverne, A A; Symons, A L

2000-10-01

Orthodontic tooth movement may be enhanced by the application of a magnetic field. Bone remodelling necessary for orthodontic tooth movement involves clastic cells, which are tartrate-resistant acid phosphatase (TRAP) positive and which may also be regulated by growth hormone (GH) via its receptor (GHR). The aim of this study was to determine the effect of a static magnetic field (SMF) on orthodontic tooth movement in the rat. Thirty-two male Wistar rats, 9 weeks old, were fitted with an orthodontic appliance directing a mesial force of 30 g on the left maxillary first molar. The appliance incorporated a weight (NM) or a magnet (M). The animals were killed at 1, 3, 7, or 14 days post-appliance insertion, and the maxillae processed to paraffin. Sagittal sections of the first molar were stained with haematoxylin and eosin (H&E), for TRAP activity or immunohistochemically for GHR. The percentage body weight loss/gain, magnetic flux density, tooth movement, width of the periodontal ligament (PDL), length of root resorption lacunae, and hyalinized zone were measured. TRAP and GHR-positive cells along the alveolar bone, root surface, and in the PDL space were counted. The incorporation of a SMF (100-170 Gauss) into an orthodontic appliance did not enhance tooth movement, nor greatly alter the histological appearance of the PDL during tooth movement. However significantly greater root resorption (P = 0.016), increased width of the PDL (P = 0.017) and greater TRAP activity (P = 0.001) were observed for group M at day 7 on the compression side. At day 14 no differences were observed between the appliance groups.

Morphogenesis in bat wings: linking development, evolution and ecology.

PubMed

Adams, Rick A

2008-01-01

The evolution of powered flight in mammals required specific developmental shifts from an ancestral limb morphology to one adapted for flight. Through studies of comparative morphogenesis, investigators have quantified points and rates of divergence providing important insights into how wings evolved in mammals. Herein I compare growth,development and skeletogenesis of forelimbs between bats and the more ancestral state provided by the rat (Rattus norvegicus)and quantify growth trajectories that illustrate morphological divergence both developmentally and evolutionarily. In addition, I discuss how wing shape is controlled during morphogenesis by applying multivariate analyses of wing bones and wing membranes and discuss how flight dynamics are stabilized during flight ontogeny. Further, I discuss the development of flight in bats in relation to the ontogenetic niche and how juveniles effect populational foraging patterns. In addition, I provide a hypothetical ontogenetic landscape model that predicts how and when selection is most intense during juvenile morphogenesis and test this model with data from a population of the little brown bat, Myotis lucifugus. (c) 2007 S. Karger AG, Basel

Effect of high-frequency near-infrared diode laser irradiation on periodontal tissues during experimental tooth movement in rats.

PubMed

Gunji, Hidemi; Kunimatsu, Ryo; Tsuka, Yuji; Yoshimi, Yuki; Sumi, Keisuke; Awada, Tetsuya; Nakajima, Kengo; Kimura, Aya; Hiraki, Tomoka; Hirose, Naoto; Yanoshita, Makoto; Tanimoto, Kotaro

2018-02-05

Tooth movement during orthodontic treatment is associated with bone neoplasticity and bone resorption on the tension and pressure sides. Previous clinical studies have suggested that low-power laser irradiation can accelerate tooth movement during orthodontic treatment, although the underlying mechanism remains unclear. In this study, we used a high-frequency near-infrared diode laser that generates less heat and examined the histologic changes in periodontal tissue during experimental tooth movement with laser irradiation. A nickel-titanium closed coil was mounted between the maxillary left side first molar and incisor of rats to model experimental tooth movement. The laser-irradiation and the control groups were set, and the amount of movement of the first molar on 7th and 14th days after the start of pulling of the first molar tooth on the maxillary left was measured by three-dimensional analysis of µCT. After tooth movement, tissue samples from the mesial and tension sides were collected, and successive horizontal sections were prepared and examined using hematoxylin-eosin and TRAP staining and immunohistochemical staining for RANKL, OPG, ALP, and proliferating cell nuclear antigen (PCNA). Changes in tissue temperature following laser irradiation were also examined. Laser irradiation significantly increased tooth movement compared with non-irradiated controls. Histologic staining of the pressure-side mesial root in laser-irradiated rats revealed enhanced RANKL expression and increased numbers of TRAP-positive cells compared with controls. By contrast, on the tension side, laser irradiation led to increased expression of ALP and PCNA. These data indicate that high-frequency near-infrared diode laser irradiation on the pressure side upregulates RANKL expression and accelerates osteoclast differentiation, facilitating bone resorption, whereas bone formation is induced on the tension side. This study demonstrates that high-frequency near-infrared diode laser irradiation of periodontal tissue leads to metabolic activation, which ultimately increases the rate of tooth movement. Lasers Surg. Med. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

A Curriculum Vitae of Teeth: Evolution, Generation, Regeneration

PubMed Central

Koussoulakou, Despina S.; Margaritis, Lukas H.; Koussoulakos, Stauros L.

2009-01-01

The ancestor of recent vertebrate teeth was a tooth-like structure on the outer body surface of jawless fishes. Over the course of 500,000,000 years of evolution, many of those structures migrated into the mouth cavity. In addition, the total number of teeth per dentition generally decreased and teeth morphological complexity increased. Teeth form mainly on the jaws within the mouth cavity through mutual, delicate interactions between dental epithelium and oral ectomesenchyme. These interactions involve spatially restricted expression of several, teeth-related genes and the secretion of various transcription and signaling factors. Congenital disturbances in tooth formation, acquired dental diseases and odontogenic tumors affect millions of people and rank human oral pathology as the second most frequent clinical problem. On the basis of substantial experimental evidence and advances in bioengineering, many scientists strongly believe that a deep knowledge of the evolutionary relationships and the cellular and molecular mechanisms regulating the morphogenesis of a given tooth in its natural position, in vivo, will be useful in the near future to prevent and treat teeth pathologies and malformations and for in vitro and in vivo teeth tissue regeneration. PMID:19266065

Expression of bone morphogenetic proteins and Msx genes during root formation.

PubMed

Yamashiro, T; Tummers, M; Thesleff, I

2003-03-01

Like crown development, root formation is also regulated by interactions between epithelial and mesenchymml tissues. Bone morphogenetic proteins (BMPs), together with the transcription factors Msx1 and Msx2, play important roles in these interactions during early tooth morphogenesis. To investigate the involvement of this signaling pathway in root development, we analyzed the expression patterns of Bmp2, Bmp3, Bmp4, and Bmp7 as well as Msx1 and Msx2 in the roots of mouse molars. Bmp4 was expressed in the apical mesenchyme and Msx2 in the root sheath. However, Bmps were not detected in the root sheath epithelium, and Msx transcripts were absent from the underlying mesenchyme. These findings indicate that this Bmp signaling pathway, required for tooth initiation, does not regulate root development, but we suggest that root shape may be regulated by a mechanism similar to that regulating crown shape in cap-stage tooth germs. Msx2 expression continued in the epithelial cell rests of Malassez, and the nearby cementoblasts intensely expressed Bmp3, which may regulate some functions of the fragmented epithelium.

A model of growth restraints to explain the development and evolution of tooth shapes in mammals.

PubMed

Osborn, Jeffrey W

2008-12-07

The problem investigated here is control of the development of tooth shape. Cells at the growing soft tissue interface between the ectoderm and mesoderm in a tooth anlage are observed to buckle and fold into a template for the shape of the tooth crown. The final shape is created by enamel secreted onto the folds. The pattern in which the folds develop is generally explained as a response to the pattern in which genes are locally expressed at the interface. This congruence leaves the problem of control unanswered because it does not explain how either pattern is controlled. Obviously, cells are subject to Newton's laws of motion so that mechanical forces and constraints must ultimately cause the movements of cells during tooth morphogenesis. A computer model is used to test the hypothesis that directional resistances to growth of the epithelial part of the interface could account for the shape into which the interface folds. The model starts with a single epithelial cell whose growth is constrained by 4 constant directional resistances (anterior, posterior, medial and lateral). The constraints force the growing epithelium to buckle and fold. By entering into the model different values for these constraints the modeled epithelium is induced to buckle and fold into the different shapes associated with the evolution of a human upper molar from that of a reptilian ancestor. The patterns and sizes of cusps and the sequences in which they develop are all correctly reproduced. The model predicts the changes in the 4 directional constraints necessary to develop and evolve from one tooth shape into another. I conclude more generally expressed genes that control directional resistances to growth, not locally expressed genes, may provide the information for the shape into which a tooth develops.

Vascular endothelial growth factor and nitric oxide synthase expression in human tooth germ development.

PubMed

Mastrangelo, F; Sberna, M T; Tettamanti, L; Cantatore, G; Tagliabue, A; Gherlone, E

2016-01-01

Vascular Endothelia Growth Factor (VEGF) and Nitric Oxide Synthase (NOS) expression, were evaluated in human tooth germs at two different stages of embryogenesis, to clarify the role of angiogenesis during tooth tissue differentiation and growth. Seventy-two third molar germ specimens were selected during oral surgery. Thirty-six were in the early stage and 36 in the later stage of tooth development. The samples were evaluated with Semi-quantitative Reverse Transcription-Polymerase chain Reaction analyses (RT-PcR), Western blot analysis (WB) and immunohistochemical analysis. Western blot and immunohistochemical analysis showed a VEGF and NOS 1-2-3 positive reaction in all samples analysed. VEGF high positive decrease reaction was observed in stellate reticulum cells, ameloblast and odontoblast clusters in early stage compared to later stage of tooth germ development. Comparable VEGF expression was observed in endothelial cells of early and advanced stage growth. NOS1 and NOS3 expressions showed a high increased value in stellate reticulum cells, and ameloblast and odontoblast clusters in advanced stage compared to early stage of development. The absence or only moderate positive reaction of NOS2 was detected in all the different tissues. Positive NOS2 expression showed in advanced stage of tissue development compared to early stage. The action of VEGF and NOS molecules are important mediators of angiogenesis during dental tissue development. VEGF high positive expression in stellate reticulum cells in the early stage of tooth development compared to the later stage and the other cell types, suggests a critical role of the stellate reticulum during dental embryo-morphogenesis.

Synergistic acceleration of experimental tooth movement by supplementary high-frequency vibration applied with a static force in rats.

PubMed

Takano-Yamamoto, Teruko; Sasaki, Kiyo; Fatemeh, Goudarzi; Fukunaga, Tomohiro; Seiryu, Masahiro; Daimaruya, Takayoshi; Takeshita, Nobuo; Kamioka, Hiroshi; Adachi, Taiji; Ida, Hiroto; Mayama, Atsushi

2017-10-25

Several recent prospective clinical trials have investigated the effect of supplementary vibration applied with fixed appliances in an attempt to accelerate tooth movement and shorten the duration of orthodontic treatment. Among them, some studies reported an increase in the rate of tooth movement, but others did not. This technique is still controversial, and the underlying cellular and molecular mechanisms remain unclear. In the present study, we developed a new vibration device for a tooth movement model in rats, and investigated the efficacy and safety of the device when used with fixed appliances. The most effective level of supplementary vibration to accelerate tooth movement stimulated by a continuous static force was 3 gf at 70 Hz for 3 minutes once a week. Furthermore, at this optimum-magnitude, high-frequency vibration could synergistically enhance osteoclastogenesis and osteoclast function via NF-κB activation, leading to alveolar bone resorption and finally, accelerated tooth movement, but only when a static force was continuously applied to the teeth. These findings contribute to a better understanding of the mechanism by which optimum-magnitude high-frequency vibration accelerates tooth movement, and may lead to novel approaches for the safe and effective treatment of malocclusion.

Effects of piezosurgery in accelerating the movement of orthodontic alveolar bone tooth of rats and the expression mechanism of BMP-2

PubMed Central

Han, Jinyou; He, Hong

2016-01-01

The aim of the study was to investigate the effects of piezosurgery in accelerating the movement of orthodontic alveolar bone tooth of rats and the expression mechanism of bone morphogenetic protein-2 (BMP-2). Adult male Wistar rats (n=30), with an age range of 14–15 weeks, and an average weight of 250±16 g were used. The animals were randomly divided into the control and observation groups. The rats in the control group were injected with 25-dihydroxyvitamin (1,25-dihydroxycholecalciferol) into their dental ligament. The rats in the observation group were placed with an orthodontic device between the first molar and central incisor in the maxillary. On the first day after animal treatment, piezosurgery stimulation was performed on the first molar in maxillary. The changes of the movement distance of the first molar and gum surface temperature on days 1, 3, 5, 7 and 14 were then compared. Immunohistochemical staining was performed to detect the expression of BMP-2 of periodontal tissue in the tension side of the first molar. Tooth movement distance in the observation group on days 5, 7 and 14 was significantly longer than that in the control group (p<0.05). The gum surface temperature of the observation group was elevated to some extent, peaking after 20 min. BMP-2 mRNA and protein levels in the observation group were significantly higher than those of the control group at days 3, 5, 7 and 14 (p<0.05). In conclusion, piezosurgery may significantly accelerate the movement of orthodontic alveolar bone tooth of rats and be associated with an increasing BMP-2 expression. PMID:27882108

Effects of piezosurgery in accelerating the movement of orthodontic alveolar bone tooth of rats and the expression mechanism of BMP-2.

PubMed

Han, Jinyou; He, Hong

2016-11-01

The aim of the study was to investigate the effects of piezosurgery in accelerating the movement of orthodontic alveolar bone tooth of rats and the expression mechanism of bone morphogenetic protein-2 (BMP-2). Adult male Wistar rats (n=30), with an age range of 14-15 weeks, and an average weight of 250±16 g were used. The animals were randomly divided into the control and observation groups. The rats in the control group were injected with 25-dihydroxyvitamin (1,25-dihydroxycholecalciferol) into their dental ligament. The rats in the observation group were placed with an orthodontic device between the first molar and central incisor in the maxillary. On the first day after animal treatment, piezosurgery stimulation was performed on the first molar in maxillary. The changes of the movement distance of the first molar and gum surface temperature on days 1, 3, 5, 7 and 14 were then compared. Immunohistochemical staining was performed to detect the expression of BMP-2 of periodontal tissue in the tension side of the first molar. Tooth movement distance in the observation group on days 5, 7 and 14 was significantly longer than that in the control group (p<0.05). The gum surface temperature of the observation group was elevated to some extent, peaking after 20 min. BMP-2 mRNA and protein levels in the observation group were significantly higher than those of the control group at days 3, 5, 7 and 14 (p<0.05). In conclusion, piezosurgery may significantly accelerate the movement of orthodontic alveolar bone tooth of rats and be associated with an increasing BMP-2 expression.

The Ovariectomized Rat as a Model for Studying Alveolar Bone Loss in Postmenopausal Women

PubMed Central

Johnston, Bryan D.; Ward, Wendy E.

2015-01-01

In postmenopausal women, reduced bone mineral density at the hip and spine is associated with an increased risk of tooth loss, possibly due to a loss of alveolar bone. In turn, having fewer natural teeth may lead to compromised food choices resulting in a poor diet that can contribute to chronic disease risk. The tight link between alveolar bone preservation, tooth retention, better nutritional status, and reduced risk of developing a chronic disease begins with the mitigation of postmenopausal bone loss. The ovariectomized rat, a widely used preclinical model for studying postmenopausal bone loss that mimics deterioration of bone tissue in the hip and spine, can also be used to study mineral and structural changes in alveolar bone to develop drug and/or dietary strategies aimed at tooth retention. This review discusses key findings from studies investigating mandible health and alveolar bone in the ovariectomized rat model. Considerations to maximize the benefits of this model are also included. These include the measurement techniques used, the age at ovariectomy, the duration that a rat is studied after ovariectomy and habitual diet consumed. PMID:26060817

Identification of a novel putative signaling center, the tertiary enamel knot in the postnatal mouse molar tooth.

PubMed

Luukko, Keijo; Løes, Sigbjørn; Furmanek, Tomasz; Fjeld, Karianne; Kvinnsland, Inger Hals; Kettunen, Paivi

2003-03-01

The final shape of the molar tooth crown is thought to be regulated by the transient epithelial signaling centers in the cusp tips, the secondary enamel knots (SEKs), which are believed to disappear after initiation of the cusp growth. We investigated the developmental fate of the signaling center using the recently characterized Slit1 enamel knot marker as a lineage tracer during morphogenesis of the first molar and crown calcification in the mouse. In situ hybridization analysis showed that after Fgf4 downregulation in the SEK, Slit1 expression persisted in the deep compartment of the knot. After the histological disappearance of the SEK, Slit1 expression was evident in a novel epithelial cell cluster, which we call the tertiary enamel knot (TEK) next to the enamel-free area (EFA)-epithelium at the cusp tips. In embryonic tooth, Slit1 was also observed in the stratum intermedium (SI) and stellate reticulum cells between the parallel SEKs correlating to the area where the inner enamel epithelium cells do not proliferate. After birth, the expression of Slit1 persisted in the SI cells of the transverse connecting lophs of the parallel cusps above the EFA-cells. These results demonstrate the presence of a novel putative signaling center, the TEK, in the calcifying tooth. Moreover, our results suggest that Slit1 signaling may be involved in the regulation of molar tooth shape by regulating epithelial cell proliferation and formation of EFA of the crown.

Microscopic evaluation of induced tooth movement after subluxation trauma: an experimental study in rats

PubMed Central

Busato, Mauro Carlos Agner; Pereira, Alex Luiz Pozzobon; Sonoda, Celso Koogi; Cuoghi, Osmar Aparecido; de Mendonça, Marcos Rogério

2014-01-01

Objective The objective of this study was to assess the histological alterations that occurred in the periodontal area of rat molars submitted to induced tooth movement (ITM) right after an intentional trauma (subluxation). Methods Forty adult male Wistar rats (Rattus norvegicus albinus) were selected. The animals were divided into eight groups (n = 5), according to the combination of variables: Group 1 - control (neither trauma nor ITM); Group 2 - ITM; Groups 3, 4, 5 and 6 - dentoalveolar trauma groups corresponding, respectively, to 1, 3, 8 and 10 days after trauma; Groups 7 and 8 - the animals' molars were subjected to a 900 cN impact and, one and three days after the trauma event, tooth movement was induced. The rats' maxillary first molars were mesially moved during seven days with a closed coil (50 cN). After the experimental period of each group, the animals were sacrificed by anesthetic overdose and the right maxillas were removed and processed for histological analysis under light microscopy. Results In the animals of group 3, 4, 5 and 6, the histological alterations were not very significant. Consequently, the effect of induced tooth movement right after a subluxation event (groups 7 and 8) was very similar to those described for Group 2. Conclusion There was no difference in the quality of periodontal repair when ITM was applied to teeth that had suffered a subluxation trauma. PMID:24713565

A Novel Rat Model of Orthodontic Tooth Movement Using Temporary Skeletal Anchorage Devices: 3D Finite Element Analysis and In Vivo Validation

PubMed Central

Stevenson, Thomas; Doschak, Michael

2014-01-01

The aim of this animal study was to develop a model of orthodontic tooth movement using a microimplant as a TSAD in rodents. A finite element model of the TSAD in alveolar bone was built using μCT images of rat maxilla to determine the von Mises stresses and displacement in the alveolar bone surrounding the TSAD. For in vivo validation of the FE model, Sprague-Dawley rats (n = 25) were used and a Stryker 1.2 × 3 mm microimplant was inserted in the right maxilla and used to protract the right first permanent molar using a NiTi closed coil spring. Tooth movement measurements were taken at baseline, 4 and 8 weeks. At 8 weeks, animals were euthanized and tissues were analyzed by histology and EPMA. FE modeling showed maximum von Mises stress of 45 Mpa near the apex of TSAD but the average von Mises stress was under 25 Mpa. Appreciable tooth movement of 0.62 ± 0.04 mm at 4 weeks and 1.99 ± 0.14 mm at 8 weeks was obtained. Histological and EPMA results demonstrated no active bone remodeling around the TSAD at 8 weeks depicting good secondary stability. This study provided evidence that protracted tooth movement is achieved in small animals using TSADs. PMID:25295060

CDKL5, a protein associated with rett syndrome, regulates neuronal morphogenesis via Rac1 signaling.

PubMed

Chen, Qian; Zhu, Yong-Chuan; Yu, Jing; Miao, Sheng; Zheng, Jing; Xu, Li; Zhou, Yang; Li, Dan; Zhang, Chi; Tao, Jiong; Xiong, Zhi-Qi

2010-09-22

Mutations in cyclin-dependent kinase-like 5 (CDKL5), also known as serine/threonine kinase 9 (STK9), have been identified in patients with Rett syndrome (RTT) and X-linked infantile spasm. However, the function of CDKL5 in the brain remains unknown. Here, we report that CDKL5 is a critical regulator of neuronal morphogenesis. We identified a neuron-specific splicing variant of CDKL5 whose expression was markedly induced during postnatal development of the rat brain. Downregulating CDKL5 by RNA interference (RNAi) in cultured cortical neurons inhibited neurite growth and dendritic arborization, whereas overexpressing CDKL5 had opposite effects. Furthermore, knocking down CDKL5 in the rat brain by in utero electroporation resulted in delayed neuronal migration, and severely impaired dendritic arborization. In contrast to its proposed function in the nucleus, we found that CDKL5 regulated dendrite development through a cytoplasmic mechanism. In fibroblasts and in neurons, CDKL5 colocalized and formed a protein complex with Rac1, a critical regulator of actin remodeling and neuronal morphogenesis. Overexpression of Rac1 prevented the inhibition of dendrite growth caused by CDKL5 knockdown, and the growth-promoting effect of ectopically expressed CDKL5 on dendrites was abolished by coexpressing a dominant-negative form of Rac1. Moreover, CDKL5 was required for brain-derived neurotrophic factor (BDNF)-induced activation of Rac1. Together, these results demonstrate a critical role of CDKL5 in neuronal morphogenesis and identify a Rho GTPase signaling pathway which may contribute to CDKL5-related disorders.

Strontium ranelate improved tooth anchorage and reduced root resorption in orthodontic treatment of rats.

PubMed

Kirschneck, Christian; Wolf, Michael; Reicheneder, Claudia; Wahlmann, Ulrich; Proff, Peter; Roemer, Piero

2014-12-05

The anchorage mechanisms currently used in orthodontic treatment have various disadvantages. The objective of this study was to determine the applicability of the osteoporosis medication strontium ranelate in pharmacologically induced orthodontic tooth anchorage. In 48 male Wistar rats, a constant orthodontic force of 0.25 N was reciprocally applied to the upper first molar and the incisors by means of a Sentalloy(®) closed coil spring for two to four weeks. 50% of the animals received strontium ranelate at a daily oral dosage of 900 mg per kilogramme of body weight. Bioavailability was determined by blood analyses. The extent of tooth movement was measured both optometrically and cephalometrically (CBCT). Relative alveolar gene expression of osteoclastic markers and OPG-RANKL was assessed by qRT-PCR and root resorption area and osteoclastic activity were determined in TRAP-stained histologic sections of the alveolar process. Compared to controls, the animals treated with strontium ranelate showed up to 40% less tooth movement after four weeks of orthodontic treatment. Gene expression and histologic analyses showed significantly less osteoclastic activity and a significantly smaller root resorption area. Blood analyses confirmed sufficient bioavailability of strontium ranelate. Because of its pharmacologic effects on bone metabolism, strontium ranelate significantly reduced tooth movement and root resorption in orthodontic treatment of rats. Strontium ranelate may be a viable agent for inducing tooth anchorage and reducing undesired root resorption in orthodontic treatment. Patients under medication of strontium ranelate have to expect prolonged orthodontic treatment times. Copyright © 2014 Elsevier B.V. All rights reserved.

The influence of teriparatide in induced tooth movement: A systematic review.

PubMed

Souza-Silva, Bianca-Núbia; Rodrigues, José-Lucas-Sani-de Alcântara; Moreira, Jefferson-Chaves; Matos, Felipe-de Souza; Cesar, Carla-Patrícia-Hernandez-Alves-Ribeiro; Repeke, Carlos-Eduardo-Palanch; Paranhos, Luiz-Renato

2016-12-01

Teriparatide is a synthetic drug similar than PTH (parathyroid hormone), which is currently used as long-term treatment option for patients with bone chronic diseases, as osteoporosis; and this drug can interfere in a positive way in orthodontic movement. Objectives: The medical literature was assessed in the present systematic review in order to determine the level of scientific evidence supporting the influence of teriparatide in induced tooth movement. The PRISMA Checklist was followed in this systematic review. Four electronic databases (PubMed; Scopus; ScienceDirect; OpenGrey) were searched without implementing restrictions of year, status, and language of publications. The inclusion criteria consisted of selecting only experimental studies comparing the influence of teriparatide in tooth movement of male Wistar rats. The exclusion criteria consisted of experiments with female rats or other experimental animals, and animals with pathologic conditions. The eligible studies were evaluated based on methodological quality. Two trained examiners performed all the research steps. The initial sample comprised 700 studies, which was reduced to 664 after the exclusion of duplicates (n=36). Three articles were selected for the final qualitative analysis. The local administration of parathyroid hormone (PTH) 1-34 or PTH 1-84 revealed major effectiveness when compared with control groups and systematic administration. Additionally, the dilution of PTH 1-34 within methyl cellulose (MC) gel increased the time range for drug release, enabling to reduce the drug concentration without decreasing the effectiveness of tooth movement. Teriparatide demonstrated potential acceleration of tooth movement in Wistar rats depending on the drug concentration; drug administration; and time for drug release. Key words: Teriparatide, tooth movement, parathyroid hormone, orthodontics.

The Effect of Thyroid Hormone, Prostaglandin E2, and Calcium Gluconate on Orthodontic Tooth Movement and Root Resorption in Rats.

PubMed

Seifi, Massoud; Hamedi, Roya; Khavandegar, Zohre

2015-03-01

A major objective of investigators is to clarify the role of metabolites in achievement of maximum tooth movement with minimal root damage during orthodontic tooth movement (OTM). The aim of this study was to determine the effect of administration of thyroid hormone, prostaglandin E2, and calcium on orthodontic tooth movement and root resorption in rats. Sixty four male Wistar rats were randomly divided into 8 groups of eight rats each: 1- 20µg/kg thyroxine was injected in traperitoneally after installation of the orthodontic appliance.  2- 0.1 ml of 1 mg/ml prostaglandin E2 was injected submucosally.  3- 10% (200 mg/kg) calcium gluconate was injected.  4- Prostaglandin E2 was injected submucosally and 10% calcium was injected intraperitoneally.  5- Thyroxine was injected intraperitoneally and prostaglandin E2 was injected submucosally.  6- 20µg/kg thyroxine with calcium was injected. 7- Prostaglandin E2 was injected submucosally with calcium and thyroxine.  8- Distilled water was used in control group. The orthodontic appliances comprised of a NiTi closed coil were posteriorly connected to the right first molar and anteriorly to the upper right incisor. OTM was measured with a feeler gauge. The mid-mesial root of the first molar and the adjacent tissues were histologically evaluated. The Data were analyzed by one-way ANOVA and Student-Newman-Keuls test. The highest mean OTM was observed in the thyroxine and prostaglandin E2 group (Mean±SD = 0.7375±0.1359 mm) that was significantly different (p< 0.05). A significant difference (p< 0.05) in root resorption was observed between the prostaglandin E2 (0.0192±0.0198 mm(2)) and the other groups. It seems that the combination of thyroxine and prostaglandin E2, with a synergistic effect, would decrease the root resorption and increase the rate of orthodontic tooth movement in rats.

[Relationship between orthodontics root resorption following experimental tooth movement and the level of dentin sialoph-osphoprotein and dentin sialoprotein in gingival crevicular fluid].

PubMed

Zuo, Zhi-Gang; Hu, Min; Jiang, Huan; Tian, Li

2011-06-01

To investigate the relationship of expression of dentin sialoph-osphoprotein (DSPP) and dentin sialoprotein (DSP) in gingival crevicular fluid (GCF) with root resorption following experimental tooth movement in rats. 36 Wistar rats were divided into 3 groups on average randomly: Control group, light force group and heavy force group. The experimental teeth were drawn-off mesially by the force of 0.392 N in light force group and 0.98 N in heavy force group, with both of the maxillary central incisors as the tooth of anchorage. At the 7th day, the gingival crevicular fluid of rats were collected; the histological slices were made, including the experimental tooth and periodontal tissue; the tissues was stained with hematoxylin-eosin (HE) staining and tartrate resistant acid phosphatase (TRAP) staining to observe the histological changes of the root resorption of rats. Then the expression of DSPP and DSP were assayed by using biochemistry techniques of Western blot. Histological observation: There was not root resorption in control group. Neither root resorption nor cementoclast was observed in light force group. And in heavy force group visible root resorption came out in pressure zone. Western blot results: There was expression of DSPP and no DSP in control group, and there was the expression of DSPP and DSP in both light force group and heavy force group. The result of statistical analysis showed that there were significant differences in the expression of DSPP and DSP among three groups. The highest one was heavy force group, followed by the light force group and control group with the least amount of proteins. There is the expression of DSPP and DSP in gingival crevicular fluid following experimental tooth movement with root resorption.

Bioengineered Tooth Buds Exhibit Features of Natural Tooth Buds.

PubMed

Smith, E E; Angstadt, S; Monteiro, N; Zhang, W; Khademhosseini, A; Yelick, P C

2018-06-01

Tooth loss is a significant health issue currently affecting millions of people worldwide. Artificial dental implants, the current gold standard tooth replacement therapy, do not exhibit many properties of natural teeth and can be associated with complications leading to implant failure. Here we propose bioengineered tooth buds as a superior alternative tooth replacement therapy. We describe improved methods to create highly cellularized bioengineered tooth bud constructs that formed hallmark features that resemble natural tooth buds such as the dental epithelial stem cell niche, enamel knot signaling centers, transient amplifying cells, and mineralized dental tissue formation. These constructs were composed of postnatal dental cells encapsulated within a hydrogel material that were implanted subcutaneously into immunocompromised rats. To our knowledge, this is the first report describing the use of postnatal dental cells to create bioengineered tooth buds that exhibit evidence of these features of natural tooth development. We propose future bioengineered tooth buds as a promising, clinically relevant tooth replacement therapy.

Ability of mini-implant-facilitated micro-osteoperforations to accelerate tooth movement in rats.

PubMed

Cheung, Tracy; Park, Juyoung; Lee, Deborah; Kim, Catherine; Olson, Jeffrey; Javadi, Shadi; Lawson, Gregory; McCabe, James; Moon, Won; Ting, Kang; Hong, Christine

2016-12-01

Although current techniques for accelerated tooth movement often involve invasive surgical procedures, micro-osteoperforations (MOPs) using mini-implants may facilitate orthodontic tooth movement without raising flaps, reduce surgical risks, and increase patient acceptance. In this study, we evaluated the effectiveness of mini-implant-facilitated MOPs in inducing accelerated tooth movement and investigated the potential risks for root resorption. Five MOPs were placed on the left side around the maxillary first molars in 6 rats using an automated mini-implant driver, whereas the right side received no MOPs as the control. Closed-coiled springs were secured from incisors to first molars for orthodontic tooth movement. Tooth movement was measured, and samples underwent radiologic and histologic analyses. The MOP side exhibited a 1.86-fold increase in the rate of tooth movement with decreased bone density and bone volume around the first molars compared with the control side. Hematoxylin and eosin and tartrate-resistant acid phosphatase analyses showed increased numbers of osteoclasts as well as new bone formation. Three-dimensional volumetric analysis of all 5 roots of the maxillary first molars demonstrated no statistically significant difference in root volumes. Mini-implant-facilitated MOPs accelerated tooth movement without increased risk for root resorption and therefore may become a readily available and efficient treatment option to shorten orthodontic treatment time with improved patient acceptance. Copyright © 2016 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

Early development and replacement of the stickleback dentition

PubMed Central

Ellis, Nicholas A.; Donde, Nikunj N.; Miller, Craig T.

2017-01-01

Teeth have long served as a model system to study basic questions about vertebrate organogenesis, morphogenesis, and evolution. In non-mammalian vertebrates, teeth typically regenerate throughout adult life. Fish have evolved a tremendous diversity in dental patterning in both their oral and pharyngeal dentitions, offering numerous opportunities to study how morphology develops, regenerates, and evolves in different lineages. Threespine stickleback fish (Gasterosteus aculeatus) have emerged as a new system to study how morphology evolves, and provide a particularly powerful system to study the development and evolution of dental morphology. Here we describe the oral and pharyngeal dentitions of stickleback fish, providing additional morphological, histological, and molecular evidence for homology of oral and pharyngeal teeth. Focusing on the ventral pharyngeal dentition in a dense developmental time course of lab-reared fish, we describe the temporal and spatial consensus sequence of early tooth formation. Early in development, this sequence is highly stereotypical and consists of seventeen primary teeth forming the early tooth field, followed by the first tooth replacement event. Comparing this detailed morphological and ontogenetic sequence to that described in other fish reveals that major changes to how dental morphology arises and regenerates have evolved across different fish lineages. PMID:27145214

The effects of systemic stress on orthodontic tooth movement.

PubMed

Gameiro, Gustavo Hauber; Nouer, Darcy Flávio; Pereira-Neto, Joáo Sarmento; Urtado, Marília Bertoldo; Novaes, Pedro Duarte; de Castro, Margaret; Veiga, Maria Cecília Ferraz Arruda

2008-11-01

To determine if systemic stress affects the biological reactions occurring during orthodontic tooth movement. Four groups of male 10 week-old Wistar rats were used. Group A animals (N=10) were restrained for one hour per day for 40 days; Group B animals (N=10) were restrained for one hour per day for three days; Group C (N=10) and Group D (N=8) animals were unrestrained. The upper left first molars in the rats in Groups A (long-term stress), B (short-term stress) and C (control) were moved mesially during the last 14 days of the experiment. The animals in Group D (N=8) were used for body weight and hormonal dosage comparisons only. They were not subjected to any stress and did not have appliances fitted. All animals were killed at 18 weeks of age and blood collected for measurement of plasma corticosterone. Tooth movement was measured with an electronic caliper. The right and left hemi-maxillae of five rats from each group were removed and the number of tartrate-resistant acid phosphatase (TRAP) positive cells, defined as osteoclasts, adjacent to the mesial roots of the upper first molars counted. The contralateral side in each animal served as the control (split-mouth design). Corticosterone levels were significantly higher in the stressed groups (Groups A and B) than in the control group (Group C). Tooth movement was significantly greater in Group A (long-term stress) compared with Group B (short-term stress) and Group C (control), which did not differ from each other. There were significantly more osteoclasts in the long-term stress group than in the short-term stress and control groups. Persistent systemic stress increases bone resorption during orthodontic tooth movement. Systemic stress may affect the rate of tooth movement during orthodontic treatment.

Adaptation of BAp crystal orientation to stress distribution in rat mandible during bone growth

NASA Astrophysics Data System (ADS)

Nakano, T.; Fujitani, W.; Ishimoto, T.; Umakoshi, Y.

2009-05-01

Biological apatite (BAp) c-axis orientation strongly depends on stress distribution in vivo and tends to align along the principal stress direction in bones. Dentulous mandible is subjected to a complicated stress condition in vivo during chewing but few studies have been carried out on the BAp c-axis orientation; so the adaptation of BAp crystal orientation to stress distribution was examined in rat dentulous mandible during bone growth and mastication. Female SD rats 4 to 14 weeks old were prepared, and the bone mineral density (BMD) and BAp crystal orientation were analyzed in a cross-section of mandible across the first molar focusing on two positions: separated from and just under the tooth root on the same cross-section perpendicular to the mesiodistal axis. The degree of BAp orientation was analyzed by a microbeam X-ray diffractometer using Cu-Kα radiation equipped with a detector of curved one-dimensional PSPC and two-dimensional PSPC in the reflection and transmission optics, respectively. BMD quickly increased during bone growth up to 14 weeks, although it was independent of the position from the tooth root. In contrast, BAp crystal orientation strongly depended on the age and the position from the tooth root, even in the same cross-section and direction, especially along the mesiodistal and the biting axes. With increased biting stress during bone growth, the degree of BAp orientation increased along the mesiodistal axis in a position separated from the tooth root more than that near the tooth root. In contrast, BAp preferential alignment clearly appeared along the biting axis near the tooth root. We conclude that BAp orientation rather than BMD sensitively adapts to local stress distribution, especially from the chewing stress in vivo in the mandible.

In-office tooth bleaching with 38% hydrogen peroxide promotes moderate/severe pulp inflammation and production of ll-1β, TNF-β, GPX, FGF-2 and osteocalcin in rats.

PubMed

Silva-Costa, Renata Suellen Galvão da; Ribeiro, Andressa Eveline de Lima; Assunção, Isauremi Vieira de; Araújo Júnior, Raimundo Fernandes de; Araújo, Aurigena Antunes de; Guerra, Gerlane Coelho Bernardo; Borges, Boniek Castillo Dutra

2018-06-11

To study the intensity of inflammatory infiltrate and production of interleukin-1β (ll-1β), tumor necrosis factor-β (TNF-β), fibroblast growth factor-2 (FGF-2), glutathione peroxidase (GPX), and osteocalcin in response to in-office tooth bleaching in rats. Twenty male Wistar rats were randomized into four groups (n=5) according to the received treatment (tooth bleaching or no treatment - control) and the period of euthanasia after treatment (24 h or 10 days). We performed tooth bleaching using a 38% hydrogen peroxide gel on maxillary and mandibular incisors. After euthanasia, incisors (20 per group) were processed for histological analysis, immunohistochemistry staining of ll-1β, TNF-β, FGF-2 and GPX and osteocalcin by immunofluorescence. We analyzed data using the Mann-Whitney and Kruskal-Wallis/Dunn tests (p<0.05). The bleached groups presented statistically significant differences regarding the pulp inflammation stage compared with the control groups. Bleached teeth showed moderate/severe inflammatory infiltrate and control groups presented absent inflammatory cells or a negligible number of mononuclear cells (p<0.001) at two times (24 h and 10 days). There was strong staining for ll-1β, TNF-β, and GPX in bleached groups at 24 h and strong staining for ll-1β, TNF-β, GPX and FGF-2 at 10 days. After 10 days of tooth bleaching, the bleached group showed a statistically superior amount of osteocalcin than the other groups (p<0.01). Tooth bleaching with 38% hydrogen peroxide causes severe pulp inflammation, but characteristics of tissue repair after 10 days.

In-office tooth bleaching with 38% hydrogen peroxide promotes moderate/severe pulp inflammation and production of ll-1β, TNF-β, GPX, FGF-2 and osteocalcin in rats

PubMed Central

2018-01-01

Abstract Objectives: To study the intensity of inflammatory infiltrate and production of interleukin-1β (ll-1β), tumor necrosis factor-β (TNF-β), fibroblast growth factor-2 (FGF-2), glutathione peroxidase (GPX), and osteocalcin in response to in-office tooth bleaching in rats. Material and Methods: Twenty male Wistar rats were randomized into four groups (n=5) according to the received treatment (tooth bleaching or no treatment - control) and the period of euthanasia after treatment (24 h or 10 days). We performed tooth bleaching using a 38% hydrogen peroxide gel on maxillary and mandibular incisors. After euthanasia, incisors (20 per group) were processed for histological analysis, immunohistochemistry staining of ll-1β, TNF-β, FGF-2 and GPX and osteocalcin by immunofluorescence. We analyzed data using the Mann-Whitney and Kruskal-Wallis/Dunn tests (p<0.05). Results: The bleached groups presented statistically significant differences regarding the pulp inflammation stage compared with the control groups. Bleached teeth showed moderate/severe inflammatory infiltrate and control groups presented absent inflammatory cells or a negligible number of mononuclear cells (p<0.001) at two times (24 h and 10 days). There was strong staining for ll-1β, TNF-β, and GPX in bleached groups at 24 h and strong staining for ll-1β, TNF-β, GPX and FGF-2 at 10 days. After 10 days of tooth bleaching, the bleached group showed a statistically superior amount of osteocalcin than the other groups (p<0.01). Conclusions: Tooth bleaching with 38% hydrogen peroxide causes severe pulp inflammation, but characteristics of tissue repair after 10 days.

A Comprehensive Mixture of Tobacco Smoke Components Retards Orthodontic Tooth Movement via the Inhibition of Osteoclastogenesis in a Rat Model

PubMed Central

Nagaie, Maya; Nishiura, Aki; Honda, Yoshitomo; Fujiwara, Shin-Ichi; Matsumoto, Naoyuki

2014-01-01

Tobacco smoke is a complex mixture of numerous components. Nevertheless, most experiments have examined the effects of individual chemicals in tobacco smoke. The comprehensive effects of components on tooth movement and bone resorption remain unexplored. Here, we have shown that a comprehensive mixture of tobacco smoke components (TSCs) attenuated bone resorption through osteoclastogenesis inhibition, thereby retarding experimental tooth movement in a rat model. An elastic power chain (PC) inserted between the first and second maxillary molars robustly yielded experimental tooth movement within 10 days. TSC administration effectively retarded tooth movement since day 4. Histological evaluation disclosed that tooth movement induced bone resorption at two sites: in the bone marrow and the peripheral bone near the root. TSC administration significantly reduced the number of tartrate-resistant acid phosphatase (TRAP)-positive osteoclastic cells in the bone marrow cavity of the PC-treated dentition. An in vitro study indicated that the inhibitory effects of TSCs on osteoclastogenesis seemed directed more toward preosteoclasts than osteoblasts. These results indicate that the comprehensive mixture of TSCs might be a useful tool for detailed verification of the adverse effects of tobacco smoke, possibly contributing to the development of reliable treatments in various fields associated with bone resorption. PMID:25322153

Effects of applying anchovy (Stolephorus insularis) substrates on the microhardness of tooth enamel in Sprague-Dawley rats

NASA Astrophysics Data System (ADS)

Hendrik, Y. C.; Puspitawati, R.; Gunawan, H. A.

2017-08-01

Anchovies (Stolephorus insularis) contain high levels of fluor in the form of CaF2. The aim of this study is to analyze changes in tooth enamel microhardness after application of anchovy substrates by feeding or as a topical fluoridation material. An in vivo study of the lower left incisors of nine Sprague-Dawley rats was conducted. The sample was comprised of baseline and treatment groups, including feeding application, topical application, negative control feeding, and negative control topical groups. The treatment groups were given 5% anchovy substrates through feeding and topical applications. After treatment, tooth samples were extracted from each of the rats for examination, and statistical analyses were performed after determining hardness numbers for enamel surfaces using Vickers microhardness tester. Vickers hardness numbers (VHNs) for anchovy substrate application and consumption by feeding (440.3 ± 24.72) were higher than for the negative control (315.80 ± 17.51). VHNs for the topical application group were higher than for the negative control (347.28 ± 28.56) and for the feeding group. The use of anchovy as a fluoridation material in form of topical application is potentially an effective method for increasing the microhardness of the tooth enamel surface

Unicuspid and bicuspid tooth crown formation in squamates.

PubMed

Handrigan, Gregory R; Richman, Joy M

2011-12-15

The molecular and developmental factors that regulate tooth morphogenesis in nonmammalian species, such as snakes and lizards, have received relatively little attention compared to mammals. Here we describe the development of unicuspid and bicuspid teeth in squamate species. The simple, cone-shaped tooth crown of the bearded dragon and ball python is established at cap stage and fixed in shape by the differentiation of cells and the secretion of dental matrices. Enamel production, as demonstrated by amelogenin expression, occurs relatively earlier in squamate teeth than in mouse molars. We suggest that the early differentiation in squamate unicuspid teeth at cap stage correlates with a more rudimentary tooth crown shape. The leopard gecko can form a bicuspid tooth crown despite the early onset of differentiation. Cusp formation in the gecko does not occur by the folding of the inner enamel epithelium, as in the mouse molar, but by the differential secretion of enamel. Ameloblasts forming the enamel epithelial bulge, a central swelling of cells in the inner enamel epithelium, secrete amelogenin at cap stage, but cease to do so by bell stage. Meanwhile, other ameloblasts in the inner enamel epithelium continue to secrete enamel, forming cusp tips on either side of the bulge. Bulge cells specifically express the gene Bmp2, which we suggest serves as a pro-differentiation signal for cells of the gecko enamel organ. In this regard, the enamel epithelial bulge of the gecko may be more functionally analogous to the secondary enamel knot of mammals than the primary enamel knot. Copyright © 2011 Wiley Periodicals, Inc., A Wiley Company.

Comparative study of MSX-2, DLX-5, and DLX-7 gene expression during early human tooth development.

PubMed

Davideau, J L; Demri, P; Hotton, D; Gu, T T; MacDougall, M; Sharpe, P; Forest, N; Berdal, A

1999-12-01

Msx and Dlx family transcription factors are key elements of craniofacial development and act in specific combinations with growth factors to control the position and shape of various skeletal structures in mice. In humans, the mutations of MSX and DLX genes are associated with specific syndromes, such as tooth agenesis, craniosynostosis, and tricho-dento-osseous syndrome. To establish some relationships between those reported human syndromes, previous experimental data in mice, and the expression patterns of MSX and DLX homeogenes in the human dentition, we investigated MSX-2, DLX-5, and DLX-7 expression patterns and compared them in orofacial tissues of 7.5- to 9-wk-old human embryos by using in situ hybridization. Our data showed that MSX-2 was strongly expressed in the progenitor cells of human orofacial skeletal structures, including mandible and maxilla bones, Meckel's cartilage, and tooth germs, as shown for DLX-5. DLX-7 expression was restricted to the vestibular lamina and, later on, to the vestibular part of dental epithelium. The comparison of MSX-2, DLX-5, and DLX-7 expression patterns during the early stages of development of different human tooth types showed the existence of spatially ordered sequences of homeogene expression along the vestibular/lingual axis of dental epithelium. The expression of MSX-2 in enamel knot, as well as the coincident expression of MSX-2, DLX-5, and DLX-7 in a restricted vestibular area of dental epithelium, suggests the existence of various organizing centers involved in the control of human tooth morphogenesis.

ROLE OF NEUROTROPINS IN RAT EMBRYONIC TESTIS MORPHOGENESIS (CORD FORMATION). (R827405)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

[Molecular cloning, expression of rat Msx-1 and Msx-2 during early embryo genesis and roles for mandibular chondrogenesis].

PubMed

Ishiguro, S

1999-03-01

Quail-chick chimera experiments have shown a contribution of carnial neural crest cells to the craniofacial skeletal elements. Moreover, tissue interactions between epithelial-mesenchymal interaction during early facial process development are required for both skeletal differentiation and morphogenesis. In this study, it was observed that Msx homeobox containing genes expressed in the facial process were important molecules of cartilage morphogenesis. Rat cDNAs were isolated and encoded by Msx-1 and -2, and then the expression patterns using in situ hybridization were investigated during early rat face development. These genes were correlatively expressed in the cranial neural crest forming area (E 9.5 dpc) and the facial process (E 12.5 dpc). Antisence inhibition of Msx genes in the E 12.5 mandibular process exhibited the alteration of their gene expression and cartilage patterns. Antisence inhibition of Msx-1 induced lack of the medial portion of cartilage, and antisence inhibition of Msx-2 enhanced chondrogenesis of mandibular process under the organ culture condition. Thus it was concluded that expression of Msx genes during mandibular process development comprises important signals of chondrogenesis.

Impact of three endocrine disruptors, Bisphenol A, Genistein and Vinclozolin on female rat enamel.

PubMed

Jedeon, K; Berdal, A; Babajko, A

2016-06-28

Concerns about the potential adverse effectsof endocrine disruptors (EDs) have been increasingover the last three decades. BisphenolA (BPA), genistein (G) and vinclozolin (V) arethree widely used EDs sharing similar effects.Since populations are exposed to many diverseEDs simultaneously, we demonstratedrecently their impact alone or combined onmale rat tooth enamel. The purpose of thisstudy was therefore to assess their effects onfemale rat tooth enamel in order to understandwhy they are differentially sensitive. Ratswere exposed daily in utero and after birth tolow doses of EDs during the critical fetal andsuckling periods when amelogenesis takesplace. Enamel of rats exposed to EDs presentedopaque areas of hypomineralization. Theproportion of affected rats was the highestin the groups of rats treated with BPA aloneand higher in males than in females (in all thegroups). Comparison of enamel key gene expressionlevels showed modulations of Klk4and Enamelin in males but no significant variationsin females. These findings show thatfemale rats are less affected than males bythe three EDs chosen in this study and suggestthat enamel hypomineralization may differbetween males and females.

Effect of supplementary zinc on orthodontic tooth movement in a rat model

PubMed Central

Sadegh, Ahmad Akhoundi Mohammad; Rezvaneh, Ghazanfari; Shahroo, Etemad-Moghadam; Mojgan, Alaeddini; Azam, Khorshidian; Shahram, Rabbani; Reza, Shamshiri Ahmad; Nafiseh, Momeni

2016-01-01

ABSTRACT Introduction: Osteoclasts and osteoblasts are responsible for regulating bone homeostasis during which the trace element zinc has been shown to exert a cumulative effect on bone mass by stimulating osteoblastic bone formation and inhibiting osteoclastic bone resorption. Objective: The aim of the present study was to investigate the effects of zinc (Zn) on orthodontic tooth movement (OTM) in a rat model. Material and Methods: A total of 44 male Wistar rats were divided into four groups of 11 animals each and received 0, 1.5, 20 and 50 ppm Zn in distilled water for 60 days. In the last 21 days of the study, nickel-titanium closed coil springs were ligated between maxillary right incisors and first molars of all rats, and tooth movement was measured at the end of this period. Histological analysis of hematoxylin/eosin slides was performed to assess root resorption lacunae, osteoclast number and periodontal ligament (PDL) width. Results: Mean OTM was calculated as 51.8, 49.1, 35.5 and 45 µm in the 0, 1.5, 20 and 50 ppm zinc-receiving groups, respectively. There were no significant differences in neither OTM nor histological parameters among the study groups (p > 0.05). Conclusion: According to the results obtained in the current investigation, increase in supplementary zinc up to 50 ppm does not affect the rate of OTM neither bone and root resorption in rats. PMID:27275614

The Effect of Thyroid Hormone, Prostaglandin E2, and Calcium Gluconate on Orthodontic Tooth Movement and Root Resorption in Rats

PubMed Central

Seifi, Massoud; Hamedi, Roya; Khavandegar, Zohre

2015-01-01

Statement of the Problem A major objective of investigators is to clarify the role of metabolites in achievement of maximum tooth movement with minimal root damage during orthodontic tooth movement (OTM). Purpose The aim of this study was to determine the effect of administration of thyroid hormone, prostaglandin E2, and calcium on orthodontic tooth movement and root resorption in rats. Materials and Method Sixty four male Wistar rats were randomly divided into 8 groups of eight rats each: 1- 20µg/kg thyroxine was injected in traperitoneally after installation of the orthodontic appliance.  2- 0.1 ml of 1 mg/ml prostaglandin E2 was injected submucosally.  3- 10% (200 mg/kg) calcium gluconate was injected.  4- Prostaglandin E2 was injected submucosally and 10% calcium was injected intraperitoneally.  5- Thyroxine was injected intraperitoneally and prostaglandin E2 was injected submucosally.  6- 20µg/kg thyroxine with calcium was injected. 7- Prostaglandin E2 was injected submucosally with calcium and thyroxine.  8- Distilled water was used in control group. The orthodontic appliances comprised of a NiTi closed coil were posteriorly connected to the right first molar and anteriorly to the upper right incisor. OTM was measured with a feeler gauge. The mid-mesial root of the first molar and the adjacent tissues were histologically evaluated. The Data were analyzed by one-way ANOVA and Student-Newman-Keuls test. Results The highest mean OTM was observed in the thyroxine and prostaglandin E2 group (Mean±SD = 0.7375±0.1359 mm) that was significantly different (p< 0.05). A significant difference (p< 0.05) in root resorption was observed between the prostaglandin E2 (0.0192±0.0198 mm2) and the other groups. Conclusion It seems that the combination of thyroxine and prostaglandin E2, with a synergistic effect, would decrease the root resorption and increase the rate of orthodontic tooth movement in rats. PMID:26106633

Effects of caffeic acid phenethyl ester on palatal mucosal defects and tooth extraction sockets

PubMed Central

Günay, Ahmet; Arpağ, Osman Fatih; Atilgan, Serhat; Yaman, Ferhan; Atalay, Yusuf; Acikan, İzzet

2014-01-01

Aim The purpose of this study was to evaluate the effects of caffeic acid phenethyl ester (CAPE) on palatal mucosal defects and tooth extraction sockets in an experimental model. Materials and methods Forty-two male Sprague-Dawley rats with a mean age of 7 weeks and weighing 280–490 g were used in this study. The rats were randomly divided into two groups: group A (the control group, n=21) and group B (the experimental group, n=21). Under anesthesia with ketamine (8 mg/100 g, intraperitoneally), palatal mucosal defects were created and tooth extraction was performed in the rats in groups A and B. Group A received no treatment, whereas group B received CAPE. CAPE was injected daily (10 μmol/kg, intraperitoneally). The rats were killed on days 7, 14, and 30 after the procedures. Palatal mucosa healing and changes in bone tissue and fibrous tissue were evaluated histopathologically. Result Pairwise comparisons showed no statistically significant difference between days 7 and 14 in either group (P>0.05). At day 30, bone healing was significantly better in group B (CAPE) than in group A (control) (P<0.05). Fibrinogen levels at day 30 were significantly higher in group A (control) than in group B (CAPE) (P<0.05). Pairwise comparisons showed no statistically significant difference in palatal mucosa healing levels between days 7 and 14 in both groups (P>0.05). Conclusion In conclusion, the findings of this study suggest that CAPE can significantly improve tooth socket healing. PMID:25364232

Comparisons of orthodontic root resorption under heavy and jiggling reciprocating forces during experimental tooth movement in a rat model.

PubMed

Hikida, Takuji; Yamaguchi, Masaru; Shimizu, Mami; Kikuta, Jun; Yoshino, Tomokazu; Kasai, Kazutaka

2016-07-01

Root mobility due to reciprocating movement of the tooth (jiggling) may exacerbate orthodontic root resorption (ORR). "Jiggling" describes mesiodistal or buccolingual movement of the roots of the teeth during orthodontic treatment. In the present study, buccolingual movement is described as "jiggling." We aimed to investigate the relationship between ORR and jiggling and to test for positive cell expression in odontoclasts in resorbed roots during experimental tooth movement (jiggling) in vivo. Male Wistar rats were divided into control, heavy force (HF), optimal force (OF), and jiggling force (JF) groups. The expression levels of cathepsin K, matrix metalloproteinase (MMP)-9 protein, interleukin (IL)-6, cytokine-induced neutrophil chemoattractant 1 (CINC-1; an IL-8-related protein in rodents), receptor activator of nuclear factor κB ligand (RANKL), and osteoprotegerin protein in the dental root were determined using immunohistochemistry. On day 21, a greater number of root resorption lacunae, which contained multinucleated odontoclasts, were observed in the palatal roots of rats in the JF group than in rats from other groups. Furthermore, there was a significant increase in the numbers of cathepsin K-positive and MMP-9-positive odontoclasts in the JF group on day 21. Immunoreactivities for IL-6, CINC-1, and RANKL were stronger in resorbed roots exposed to jiggling than in the other groups on day 21. Negative reactivity was observed in the controls. These results suggest that jiggling may induce ORR via inflammatory cytokine production during orthodontic tooth movement, and that jiggling may be a risk factor for ORR.

Comparisons of orthodontic root resorption under heavy and jiggling reciprocating forces during experimental tooth movement in a rat model

PubMed Central

Hikida, Takuji; Shimizu, Mami; Kikuta, Jun; Yoshino, Tomokazu; Kasai, Kazutaka

2016-01-01

Objective Root mobility due to reciprocating movement of the tooth (jiggling) may exacerbate orthodontic root resorption (ORR). "Jiggling" describes mesiodistal or buccolingual movement of the roots of the teeth during orthodontic treatment. In the present study, buccolingual movement is described as "jiggling." We aimed to investigate the relationship between ORR and jiggling and to test for positive cell expression in odontoclasts in resorbed roots during experimental tooth movement (jiggling) in vivo. Methods Male Wistar rats were divided into control, heavy force (HF), optimal force (OF), and jiggling force (JF) groups. The expression levels of cathepsin K, matrix metalloproteinase (MMP)-9 protein, interleukin (IL)-6, cytokine-induced neutrophil chemoattractant 1 (CINC-1; an IL-8-related protein in rodents), receptor activator of nuclear factor κB ligand (RANKL), and osteoprotegerin protein in the dental root were determined using immunohistochemistry. Results On day 21, a greater number of root resorption lacunae, which contained multinucleated odontoclasts, were observed in the palatal roots of rats in the JF group than in rats from other groups. Furthermore, there was a significant increase in the numbers of cathepsin K-positive and MMP-9-positive odontoclasts in the JF group on day 21. Immunoreactivities for IL-6, CINC-1, and RANKL were stronger in resorbed roots exposed to jiggling than in the other groups on day 21. Negative reactivity was observed in the controls. Conclusions These results suggest that jiggling may induce ORR via inflammatory cytokine production during orthodontic tooth movement, and that jiggling may be a risk factor for ORR. PMID:27478800

Zoledronic acid and alendronate sodium and the implications in orthodontic movement.

PubMed

Franzoni, J S; Soares, F M P; Zaniboni, E; Vedovello Filho, M; Santamaria, M P; Dos Santos, G M T; Esquisatto, M A M; Felonato, M; Mendonca, F A S; Franzini, C M; Santamaria, M

2017-08-01

To evaluate orthodontic tooth movement (OTM) in rats treated with two types of bisphosphonates (BPs), alendronate sodium (A) and zoledronic acid (Z). In all, 15 male Wistar rats were randomly divided into three groups. Group OTM+A: orthodontic tooth movement and subcutaneous administration of alendronate sodium (2.5 mg/kg); Group OTM+Z: orthodontic tooth movement and subcutaneous administration of zoledronic acid (0.02 mg/kg), and Group OTM: orthodontic tooth movement and subcutaneous injection of saline. The BPs were administered once a day during 25 days before OTM started and during 10 days of OTM. The left upper first molar was moved with a stainless-steel closed coil spring which delivered an initial force of 0.4N. OTM was measured with a digital caliper comparing the moved and the contralateral side. The histomorphometric analysis counted the number of osteoclasts, inflammatory cells, blood vessels and fibroblasts (n/10 4  m 2 ) in periodontal ligament (PDL) of the distobuccal root. A reduction of 58.3% of OTM was found in Group OTM+A and 99.6% in Group OTM+Z, when compared with Group OTM. There was a significant decrease of osteoclasts and inflammatory cells in BP-treated groups. Blood vessels and fibroblastic cells decreased mainly in Group OTM+Z. Alendronate sodium and zoledronic acid have similar effects on the periodontal tissue during orthodontic treatment in rats. Especially, zoledronic acid can affect orthodontic tooth movement. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

[Effects of oral interventions on carotid artery in rats with chronic periodontitis for the detection of Porphyromonas gingivalis and the expression of C-reactive protein].

PubMed

Xiuyun, Ren; Chong, Wang; Xin, Liu; Hao, Li; Qianhui, Ma; Mu, Lin; Xuexue, Shi; Jinhua, Gao

2017-04-01

This study aimed to establish a SD rat model of chronic periodontitis (CP) merged with hyperlipidemia (HL), perform periodontal treatment, detect the expression of partial C-reactive protein (CRP) and Porphyromonas gingivalis (P. gingivalis) in the rat carotid artery, and explore the relationship between periodontitis and atherosclerosis. SD rats were randomly divided into three groups: control group (A), HL group (B), and CP+HL group (C). Group C rats were divided into natural process group (C1), scaling and root planning group (C2), and tooth extraction group (C3). Group C2 rats were randomly divided into C2-1 (scaling and root planning group) and C2-2 (scaling and root planning+minocyline+systemic antibiotics group). Group C3 rats were randomly divided into C3-1 (tooth extraction group) and C3-2 (tooth extraction+systemic antibiotic group). One rat from group B was randomly selected and sacrificed after 15 weeks. Subsequently, the carotid vascular tissue was collected for oil red O staining. Modeling was successful when foam cell formation was observed. Periodontal treatments were conducted twice, and euthanasia was performed after the experiment. Moreover, double-carotid artery bifurcation was carried out to detect the expression of CRP and P. gingivalis. Immunohistochemical and 16sRNA semiquantitative methods were used to detect the CRP expression and the relative contents of P. gingivalis, respectively. Immunohistochemical results showed that the CRP-positive expression in groups B and C was significantly higher than that in group A (P<0.05). The CRP-positive expression in other group C rats were significantly lower than that in group C1 (P<0.05). The CRP-positive expression in group C2-2 was the lowest among the groups (P<0.05). The relative quantity of P. gingivalis in group C1 was the highest and significantly higher than that in groups A and B (P<0.05). The relative quantities of P. gingivalis in groups C2-1, C2-2, C3-1, and C3-2 were significantly lower than that in group C1 (P<0.05), and the quantity in group C3-2 was the lowest (P<0.05). Rats with CP associated with HL will increase the CRP expression and oral bacteria quantity on carotid artery, and lesions will gradually aggravate. Interventions, such as periodontal basic treatment and tooth extraction, could improve carotid artery lesions. The basic treatment with local and systemic anti-inflammatory drugs exerts the most satisfactory effect on local CRP expression. Tooth extraction with antibiotics is an effective method on reducing oral bacteria in carotid artery. Periodontal basic treatment associated with local and systemic antiflammatory drugs can obviously improve the effect.
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p63 protein is essential for the embryonic development of vibrissae and teeth

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

Rufini, Alessandro; Weil, Miguel; McKeon, Frank

2006-02-17

Development of skin appendages strongly depends on epithelial-mesenchymal interactions. One of the genes involved in this process is p63, a member of the p53 family of transcription factors, essential for ectodermal development, as elucidated by the phenotype of p63 knock-out mice. Surprisingly, no information on p63 expression in tooth and hair is yet available. Here, we show p63 expression during teeth and vibrissae morphogenesis in mouse embryos and we also show a correlation with the expression patterns of the epithelial marker keratin 5 and the proliferation marker Ki67. Our results show that p63 colocalizes with both K5 and Ki67 inmore » the epithelium of developing vibrissae, while in teeth p63 is expressed, together with K5, in the undifferentiated ectoderm (enamel organ), and in ameloblasts, a subpopulation of differentiated ectodermal cells. Moreover, p63 expression in tooth seems not to be fully colocalized with nuclear Ki67 expression.« less

Increased Cell Proliferation and Gene Expression of Genes Related to Bone Remodeling, Cell Adhesion and Collagen Metabolism in the Periodontal Ligament of Unopposed Molars in Growing Rats

PubMed Central

Dorotheou, Domna; Farsadaki, Vassiliki; Bochaton-Piallat, Marie-Luce; Giannopoulou, Catherine; Halazonetis, Thanos D.; Kiliaridis, Stavros

2017-01-01

Tooth eruption, the process by which teeth emerge from within the alveolar bone into the oral cavity, is poorly understood. The post-emergent phase of tooth eruption continues throughout life, in particular, if teeth are not opposed by antagonists. The aim of the present study was to better understand the molecular processes underlying post-emergent tooth eruption. Toward this goal, we removed the crowns of the maxillary molars on one side of the mouth of 14 young rats and examined gene expression patterns in the periodontal ligaments (PDLs) of the ipsilateral and contralateral mandibular molars, 3 and 15 days later. Nine untreated rats served as controls. Expression of six genes, Adamts18, Ostn, P4ha3, Panx3, Pth1r, and Tnmd, was upregulated in unopposed molars relative to molars with antagonists. These genes function in osteoblast differentiation and proliferation, cell adhesion and collagen metabolism. Proliferation of PDL cells also increased following loss of the antagonist teeth. Interestingly, mutations in PTH1R have been linked to defects in the post-emergent phase of tooth eruption in humans. We conclude that post-emergent eruption of unopposed teeth is associated with gene expression patterns conducive to alveolar bone formation and PDL remodeling. PMID:28239357

Technique: imaging earliest tooth development in 3D using a silver-based tissue contrast agent.

PubMed

Raj, Muhammad T; Prusinkiewicz, Martin; Cooper, David M L; George, Belev; Webb, M Adam; Boughner, Julia C

2014-02-01

Looking in microscopic detail at the 3D organization of initiating teeth within the embryonic jaw has long-proved technologically challenging because of the radio-translucency of these tiny un-mineralized oral tissues. Yet 3D image data showing changes in the physical relationships among developing tooth and jaw tissues are vital to understand the coordinated morphogenesis of vertebrate teeth and jaws as an animal grows and as species evolve. Here, we present a new synchrotron-based scanning solution to image odontogenesis in 3D and in histological detail using a silver-based contrast agent. We stained fixed, intact wild-type mice aged embryonic (E) day 10 to birth with 1% Protargol-S at 37°C for 12-32 hr. Specimens were scanned at 4-10 µm pixel size at 28 keV, just above the silver K-edge, using micro-computed tomography (µCT) at the Canadian Light Source synchrotron. Synchrotron µCT scans of silver-stained embryos showed even the earliest visible stages of tooth initiation, as well as many other tissue types and structures, in histological detail. Silver stain penetration was optimal for imaging structures in intact embryos E15 and younger. This silver stain method offers a powerful yet straightforward approach to visualize at high-resolution and in 3D the earliest stages of odontogenesis in situ, and demonstrates the important of studying the tooth organ in all three planes of view. Copyright © 2013 Wiley Periodicals, Inc.

Effect of low level laser and low intensity pulsed ultrasound therapy on bone remodeling during orthodontic tooth movement in rats.

PubMed

Alazzawi, Mohammed Mahmood Jawad; Husein, Adam; Alam, Mohammad Khursheed; Hassan, Rozita; Shaari, Rumaizi; Azlina, Ahmad; Salzihan, M S

2018-04-16

Quality bone regeneration, which leads to the improvement of bone remodeling, is essential for orthodontic treatment. In order to improve bone regeneration and increase the amount of tooth movement, different techniques have been implemented. The object of this study is to compare the effects of low-level laser therapy (LLLT), low-intensity pulsed ultrasound (LIPUS), and their combination on bone remodeling during orthodontic tooth movement. Eighty (80) male, 6-week-old Sprague Dawley rats were grouped in to four groups, the first group was irradiated with (940 nm) diode laser, second group with LIPUS, and third group with combination of both LLLT and LIPUS. A forth group used was a control group in an incomplete block split-mouth design. The LLLT and LIPUS were used to treat the area around the moving tooth once a day on days 0-7, then the experiment was ended in each experimental endpoint (1, 3, 7, 14, and 21 days). For amount of tooth movement, models were imaged and analyzed. Histological examination was performed after staining with (hematoxylin and eosin) and (alizarin red and Alcian Blue) stain. One step reverse transcription-polymerase chain reaction RT-PCR was also performed to elucidate the gene expression of RANK, RANKL, OPG, and RUNX-2. The amount of tooth movement, the histological bone remodeling, and the RT-PCR were significantly greater in the treatment groups than that in the control group. Among the treatment groups, the combination group was the highest and the LIPUS group was the lowest. These findings suggest that LLLT and LIPUS can enhance the velocity of tooth movement and improve the quality of bone remodeling during orthodontic tooth movement.

Parathyroid hormone related to bone regeneration in grafted and nongrafted tooth extraction sockets in rats.

PubMed

Kuroshima, Shinichiro; Al-Salihi, Zeina; Yamashita, Junro

2013-02-01

The quality and quantity of bone formed in tooth extraction sockets impact implant therapy. Therefore, the establishment of a new approach to enhance bone formation and to minimize bone resorption is important for the success of implant therapy. In this study, we investigated whether intermittent parathyroid hormone (PTH) therapy enhanced bone formation in grafted sockets. Tooth extractions of the maxillary first molars were performed in rats, and the sockets were grafted with xenograft. Intermittent PTH was administered either for 7 days before extractions, for 14 days after extractions, or both. The effect of PTH therapy on bone formation in the grafted sockets was assessed using microcomputed tomography at 14 days after extractions. PTH therapy for 7 days before extractions was not effective to augment bone fill, whereas PTH therapy for 14 days after operation significantly augmented bone formation in the grafted sockets. Intermittent PTH therapy starting right after tooth extractions significantly enhanced bone fill in the grafted sockets, suggesting that PTH therapy can be a strong asset for the success of the ridge preservation procedure.

In vitro differentiation of human tooth germ stem cells into endothelial- and epithelial-like cells.

PubMed

Doğan, Ayşegül; Demirci, Selami; Şahin, Fikrettin

2015-01-01

Current clinical techniques in dental practice include stem cell and tissue engineering applications. Dental stem cells are promising primary cell source for mainly tooth tissue engineering. Interaction of mesenchymal stem cell with epithelial and endothelial cells is strictly required for an intact tooth morphogenesis. Therefore, it is important to investigate whether human tooth germ stem cells (hTGSCs) derived from wisdom tooth are suitable for endothelial and epithelial cell transformation in dental tissue regeneration approaches. Differentiation into endothelial and epithelial cell lineages were mimicked under defined conditions, confirmed by real time PCR, western blotting and immunocytochemical analysis by qualitative and quantitative methods. HUVECs and HaCaT cells were used as positive controls for the endothelial and epithelial differentiation assays, respectively. Immunocytochemical and western blotting analysis revealed that terminally differentiated cells expressed cell-lineage markers including CD31, VEGFR2, VE-Cadherin, vWF (endothelial cell markers), and cytokeratin (CK)-17, CK-19, EpCaM, vimentin (epithelial cell markers) in significant levels with respect to undifferentiated control cells. Moreover, high expression levels of VEGFR1, VEGFR2, VEGF, CK-18, and CK-19 genes were detected in differentiated endothelial and epithelial-like cells. Endothelial-like cells derived from hTGSCs were cultured on Matrigel, tube-like structure formations were followed as an indication for functional endothelial differentiation. hTGSCs successfully differentiate into various cell types with a broad range of functional abilities using an in vitro approach. These findings suggest that hTGSCs may serve a potential stem cell source for tissue engineering and cell therapy of epithelial and endothelial tissue. © 2014 International Federation for Cell Biology.

Changes in PGE2 signaling after submandibulectomy alter post-tooth extraction socket healing.

PubMed

Mohn, Claudia Ester; Troncoso, Gastón Rodolfo; Bozzini, Clarisa; Conti, María Inés; Fernandez Solari, Javier; Elverdin, Juan Carlos

2018-03-10

Saliva is very important to oral health, and a salivary deficit has been shown to bring serious problems to oral health. There is scant information about the mechanisms through which salivary glands participate in post-tooth extraction socket healing. Therefore, the aim of the present study was to investigate the effect of submandibulectomy (SMx), consisting of the ablation of submandibular and sublingual glands (SMG and SLG, respectively), on PGE 2 signaling and other bone regulatory molecules, such as OPG and RANKL, involved in tooth extraction socket healing. Male Wistar rats, 70 g body weight, were assigned to an experimental (subjected to SMx) or a control group (sham operated). One week later, the animals in both groups underwent bilateral extraction of the first mandibular molars. The effect of SMx on different stages of socket healing after tooth extraction (7, 14, and 30 days) was studied by evaluating some parameters of inflammation, including PGE 2 and its receptors, and of bone metabolism, as well as by performing bone biomechanical studies. SMx increased TNFα and PGE 2 content as well as cyclooxygenase-II (COX-II) expression in tooth socket tissue at almost all the studied time points. SMx also had an effect on mRNA expression of PGE 2 receptors at the different time points, but did not significantly alter osteoprotegerin (OPG) and RANKL mRNA expression at any of the studied time points. In addition, an increase in bone mass density was observed in SMx rats compared with matched controls, and the structural and mechanical bone properties of the mandibular socket bone were also affected by SMx. Our results suggest that the SMG/SLG complex regulates cellular activation and differentiation by modulating the production of molecules intervening in tooth extraction socket repair, including the PGE 2 signaling system, which would therefore account for the higher density and resistance of the newly formed bone in SMx rat. © 2018 by the Wound Healing Society.

MicroRNA miR-328 Regulates Zonation Morphogenesis by Targeting CD44 Expression

PubMed Central

Wang, Chia-Hui; Lee, Daniel Y.; Deng, Zhaoqun; Jeyapalan, Zina; Lee, Shao-Chen; Kahai, Shireen; Lu, Wei-Yang; Zhang, Yaou; Yang, Burton B.

2008-01-01

Morphogenesis is crucial to initiate physiological development and tumor invasion. Here we show that a microRNA controls zonation morphogenesis by targeting hyaluronan receptor CD44. We have developed a novel system to study microRNA functions by generating constructs expressing pre-miRNAs and mature miRNAs. Using this system, we have demonstrated that expression of miR-328 reduced cell adhesion, aggregation, and migration, and regulated formation of capillary structure. Protein analysis indicated that miR-328 repressed CD44 expression. Activities of luciferase constructs harboring the target site in CD44, but not the one containing mutation, were repressed by miR-328. Zonation morphogenesis appeared in cells transfected by miR-328: miR-328-transfected cells were present on the surface of zonating structures while the control cells stayed in the middle. MiR-328-mediated CD44 actions was validated by anti-CD44 antibody, hyaluronidase, CD44 siRNA, and CD44 expression constructs. In vivo experiments showed that CD44-silencing cells appeared as layers on the surfaces of nodules or zonating structures. Immuno-histochemistry also exhibited CD44-negative cells on the surface layers of normal rat livers and the internal zones of Portal veins. Our results demonstrate that miR-328 targets CD44, which is essential in regulating zonation morphogenesis: silencing of CD44 expression is essential in sealing the zonation structures to facilitate their extension and to inhibit complex expansion. PMID:18560585

MicroRNA miR-328 regulates zonation morphogenesis by targeting CD44 expression.

PubMed

Wang, Chia-Hui; Lee, Daniel Y; Deng, Zhaoqun; Jeyapalan, Zina; Lee, Shao-Chen; Kahai, Shireen; Lu, Wei-Yang; Zhang, Yaou; Yang, Burton B

2008-06-18

Morphogenesis is crucial to initiate physiological development and tumor invasion. Here we show that a microRNA controls zonation morphogenesis by targeting hyaluronan receptor CD44. We have developed a novel system to study microRNA functions by generating constructs expressing pre-miRNAs and mature miRNAs. Using this system, we have demonstrated that expression of miR-328 reduced cell adhesion, aggregation, and migration, and regulated formation of capillary structure. Protein analysis indicated that miR-328 repressed CD44 expression. Activities of luciferase constructs harboring the target site in CD44, but not the one containing mutation, were repressed by miR-328. Zonation morphogenesis appeared in cells transfected by miR-328: miR-328-transfected cells were present on the surface of zonating structures while the control cells stayed in the middle. MiR-328-mediated CD44 actions was validated by anti-CD44 antibody, hyaluronidase, CD44 siRNA, and CD44 expression constructs. In vivo experiments showed that CD44-silencing cells appeared as layers on the surfaces of nodules or zonating structures. Immuno-histochemistry also exhibited CD44-negative cells on the surface layers of normal rat livers and the internal zones of Portal veins. Our results demonstrate that miR-328 targets CD44, which is essential in regulating zonation morphogenesis: silencing of CD44 expression is essential in sealing the zonation structures to facilitate their extension and to inhibit complex expansion.

Regular nicotine intake increased tooth movement velocity, osteoclastogenesis and orthodontically induced dental root resorptions in a rat model

PubMed Central

Kirschneck, Christian; Maurer, Michael; Wolf, Michael; Reicheneder, Claudia; Proff, Peter

2017-01-01

Orthodontic forces have been reported to significantly increase nicotine-induced periodontal bone loss. At present, however, it is unknown, which further (side) effects can be expected during orthodontic treatment at a nicotine exposure corresponding to that of an average European smoker. 63 male Fischer344 rats were randomized in three consecutive experiments of 21 animals each (A/B/C) to 3 experimental groups (7 rats, 1/2/3): (A) cone-beam-computed tomography (CBCT); (B) histology/serology; (C) reverse-transcription quantitative real-time polymerase chain reaction (RT-qPCR)/cotinine serology—(1) control; (2) orthodontic tooth movement (OTM) of the first and second upper left molar (NiTi closed coil spring, 0.25 N); (3) OTM with 1.89 mg·kg−1 per day s.c. of L(−)-nicotine. After 14 days of OTM, serum cotinine and IL-6 concentration as well as orthodontically induced inflammatory root resorption (OIIRR), osteoclast activity (histology), orthodontic tooth movement velocity (CBCT, within 14 and 28 days of OTM) and relative gene expression of known inflammatory and osteoclast markers were quantified in the dental-periodontal tissue (RT–qPCR). Animals exposed to nicotine showed significantly heightened serum cotinine and IL-6 levels corresponding to those of regular European smokers. Both the extent of root resorption, osteoclast activity, orthodontic tooth movement and gene expression of inflammatory and osteoclast markers were significantly increased compared to controls with and without OTM under the influence of nicotine. We conclude that apart from increased periodontal bone loss, a progression of dental root resorption and accelerated orthodontic tooth movement are to be anticipated during orthodontic therapy, if nicotine consumption is present. Thus patients should be informed about these risks and the necessity of nicotine abstinence during treatment. PMID:28960194

The effects of blocking N/OFQ receptors on orofacial pain following experimental tooth movement in rats.

PubMed

Shan, Di; He, Yuwei; Long, Hu; Zhou, Yang; Liu, He; Xu, Rui; Huang, Renhuan; Lai, Wenli

2016-11-01

The aim of this study was to determine the effects of nociceptin/orphanin FQ peptide receptor (N/OFQ receptor) antagonist on orofacial pain induced by experimental tooth movement in rats. A total of 36 male Sprague-Dawley rats weighing 200-300 g were divided into six groups: a control group, force group, force+saline intraperitoneal group, force+saline periodontal group, force+UFP-101 ([Nphe¹,Arg¹⁴,Lys¹⁵]N/OFQ-NH ₂ antagonist for N/OFQ receptor) intraperitoneal group, and force+UFP-1 01 periodontal group. Closed coil springs were ligated between the upper incisors and first molar to exert an orthodontic force (40 g) between the teeth. Injectable administration dosages were 30 μl saline or 30 μl saline containing 0.03 mg/kg UFP-1 01. Following the injections, orofacial pain levels were assessed through directed face grooming (mouth wiping). Statistical analyses were performed in SPSS 17.0 (Statistical Package for the Social Sciences) and p values less than 0.05 were considered as statistically significant. Orofacial pain levels were significantly higher in the force group than in the control group. Orofacial pain levels differed significantly between the force)group, force+saline periodontal group and force+UFP-101 periodontal group, but were similar between the control group, force+UFP-101 intraperitoneal group and force+saline intraperitoneal group. Moreover, orofacial pain levels did not differ between the force group, force+saline intraperitoneal group and force+UFP-1 01 intraperitoneal group. Periodontal, but not intraperitoneal, administration of UFP-101 could alleviate orofacial pain induced by experimental tooth movement in rats, suggesting that periodontal N/OFQ receptors participate in orofacial pain induced by experimental tooth movement.

Construction of a cDNA library for miniature pig mandibular deciduous molars

PubMed Central

2014-01-01

Background The miniature pig provides an excellent experimental model for tooth morphogenesis because its diphyodont and heterodont dentition resembles that of humans. However, little information is available on the process of tooth development or the exact molecular mechanisms controlling tooth development in miniature pigs or humans. Thus, the analysis of gene expression related to each stage of tooth development is very important. Results In our study, after serial sections were made, the development of the crown of the miniature pigs’ mandibular deciduous molar could be divided into five main phases: dental lamina stage (E33-E35), bud stage (E35-E40), cap stage (E40-E50), early bell stage (E50-E60), and late bell stage (E60-E65). Total RNA was isolated from the tooth germ of miniature pig embryos at E35, E45, E50, and E60, and a cDNA library was constructed. Then, we identified cDNA sequences on a large scale screen for cDNA profiles in the developing mandibular deciduous molars (E35, E45, E50, and E60) of miniature pigs using Illumina Solexa deep sequencing. Microarray assay was used to detect the expression of genes. Lastly, through Unigene sequence analysis and cDNA expression pattern analysis at E45 and E60, we found that 12 up-regulated and 15 down-regulated genes during the four periods are highly conserved genes homologous with known Homo sapiens genes. Furthermore, there were 6 down-regulated and 2 up-regulated genes in the miniature pig that were highly homologous to Homo sapiens genes compared with those in the mouse. Conclusion Our results not only identify the specific transcriptome and cDNA profile in developing mandibular deciduous molars of the miniature pig, but also provide useful information for investigating the molecular mechanism of tooth development in the miniature pig. PMID:24750690

The Effect of Simvastatin on mRNA Expression of Transforming Growth Factor-β1, Bone Morphogenetic Protein-2 and Vascular Endothelial Growth Factor in Tooth Extraction Socket

PubMed Central

Liu, Chang; Wu, Zhe; Sun, Hong-chen

2009-01-01

Aim To determine the effect of local simvastatin application on the mRNA expression level of transforming growth factor-β1 (TGF-β1), bone morphogenetic protein-2 (BMP-2) and vascular endothelial growth factor (VEGF) in the tooth sockets of rat. Methodology Forty-eight male Wistar rats were randomly divided into experimental and control groups (n=24). Polylactic acid/polyglycolic acid copolymer carriers, with or without simvastatin, were implanted into extraction sockets of right mandibular incisors. The expression of TGF-β1, BMP-2 and VEGF mRNA was determined by in situ hybridization in the tooth extraction socket at five days, one week, two weeks and four weeks after implantation. Results The fusiform stroma cells in the tooth extraction socket began to express TGF-β1, BMP-2 and VEGF mRNA in both experimental and control groups from one week after tooth extraction until the end of experiment. The expression of TGF-β1 and BMP-2 mRNA in the experimental group was significantly up-regulated after one, two and four weeks, and expression of VEGF mRNA was significantly increased after one and two weeks compared with that in the control group. Conclusion The findings indicate that local administration of simvastatin can influence alveolar bone remodeling by regulating the expression of a school of growth factors which are crucial to osteogenesis in the tooth extraction socket. PMID:20687301

Msx homeobox gene family and craniofacial development.

PubMed

Alappat, Sylvia; Zhang, Zun Yi; Chen, Yi Ping

2003-12-01

Vertebrate Msx genes are unlinked, homeobox-containing genes that bear homology to the Drosophila muscle segment homeobox gene. These genes are expressed at multiple sites of tissue-tissue interactions during vertebrate embryonic development. Inductive interactions mediated by the Msx genes are essential for normal craniofacial, limb and ectodermal organ morphogenesis, and are also essential to survival in mice, as manifested by the phenotypic abnormalities shown in knockout mice and in humans. This review summarizes studies on the expression, regulation, and functional analysis of Msx genes that bear relevance to craniofacial development in humans and mice. Key words: Msx genes, craniofacial, tooth, cleft palate, suture, development, transcription factor, signaling molecule.

Effects of loxoprofen on the apical root resorption during orthodontic tooth movement in rats.

PubMed

Yamamoto, Taeko; Kaku, Masato; Sumi, Hiromi; Yashima, Yuka; Izumino, Jin; Tanimoto, Kotaro

2018-01-01

Studies have revealed that severe apical root resorption during tooth movement is caused by the noninfective inflammatory reaction of apical root tissues. We hypothesized that loxoprofen can suppress apical root resorption during tooth movement. Cyclic tensile force (CTF) of 10 kPa was applied to the human pulp cells for 48 hours by the Flexcell Strain Unit. Loxoprofen (10 and 100 μM) was added to the culture cells, and expression of cyclooxygenase (COX)-1, COX-2, interleukin (IL)-1β, receptor activator of nuclear factor kappa-B ligand (RANKL), tumor necrosis factor (TNF)-α, and macrophage colony-stimulating factor (M-CSF) were examined. To determine the effects of loxoprofen sodium on apical root reabsorption during tooth movement, the upper first molars of 7-week-old rats were subjected to mesial movement by 10g force for 30 days with or without the oral administration of loxoprofen. Gene expression and protein concentration of COX-1, COX-2, IL-1β, TNF-α, RANKL and M-CSF were significantly higher in the CTF group than in the control group. However, these levels were decreased by loxoprofen administration. After orthodontic tooth movement, the expression of IL-1β, TNF-α, RANKL and M-CSF decreased in the loxoprofen group than in the control group by immunohistochemical staining. In comparison to control group, less number of odontoclasts and a decrease in the amount of apical root resorption was observed in the loxoprofen group. Many osteoclasts became visible on the pressure side of the alveolar bone in the both groups, and the amount of tooth movement did not show a significant difference. These findings demonstrate that severe apical root resorption may be suppressed by loxoprofen administration, without a disturbance of tooth movement.

Effects of loxoprofen on the apical root resorption during orthodontic tooth movement in rats

PubMed Central

Sumi, Hiromi; Yashima, Yuka; Izumino, Jin

2018-01-01

Studies have revealed that severe apical root resorption during tooth movement is caused by the noninfective inflammatory reaction of apical root tissues. We hypothesized that loxoprofen can suppress apical root resorption during tooth movement. Cyclic tensile force (CTF) of 10 kPa was applied to the human pulp cells for 48 hours by the Flexcell Strain Unit. Loxoprofen (10 and 100 μM) was added to the culture cells, and expression of cyclooxygenase (COX)-1, COX-2, interleukin (IL)-1β, receptor activator of nuclear factor kappa-B ligand (RANKL), tumor necrosis factor (TNF)-α, and macrophage colony-stimulating factor (M-CSF) were examined. To determine the effects of loxoprofen sodium on apical root reabsorption during tooth movement, the upper first molars of 7-week-old rats were subjected to mesial movement by 10g force for 30 days with or without the oral administration of loxoprofen. Gene expression and protein concentration of COX-1, COX-2, IL-1β, TNF-α, RANKL and M-CSF were significantly higher in the CTF group than in the control group. However, these levels were decreased by loxoprofen administration. After orthodontic tooth movement, the expression of IL-1β, TNF-α, RANKL and M-CSF decreased in the loxoprofen group than in the control group by immunohistochemical staining. In comparison to control group, less number of odontoclasts and a decrease in the amount of apical root resorption was observed in the loxoprofen group. Many osteoclasts became visible on the pressure side of the alveolar bone in the both groups, and the amount of tooth movement did not show a significant difference. These findings demonstrate that severe apical root resorption may be suppressed by loxoprofen administration, without a disturbance of tooth movement. PMID:29694352

Interactive effects of periodontitis and orthodontic tooth movement on dental root resorption, tooth movement velocity and alveolar bone loss in a rat model.

PubMed

Kirschneck, Christian; Fanghänel, Jochen; Wahlmann, Ulrich; Wolf, Michael; Roldán, J Camilo; Proff, Peter

2017-03-01

Many adult orthodontic patients suffer from chronic periodontitis with recurrent episodes of active periodontal inflammation. As their number is steadily increasing, orthodontists are more and more frequently challenged by respective treatment considerations. However, little is currently known regarding interactive effects on undesired dental root resorption (DRR), tooth movement velocity, periodontal bone loss and the underlying cellular and tissue reactions. A total of 63 male Fischer344 rats were used in three consecutive experiments employing 21 animals each (A/B/C), randomly assigned to 3 experimental groups (n=7, 1/2/3), respectively: (A) CBCT; (B) histology/serology; (C) RT-qPCR-(1) control; (2) orthodontic tooth movement (OTM) of the first/second upper left molars (NiTi coil spring, 0.25N); (3) OTM with experimentally induced periodontitis (cervical silk ligature). After 14days of OTM, we quantified blood leukocyte level, DRR, osteoclast activity and relative gene expression of inflammatory and osteoclast marker genes within the dental-periodontal tissue as well as tooth movement velocity and periodontal bone loss after 14 and 28 days. The experimentally induced periodontal bone loss was significantly increased by concurrent orthodontic force application. Periodontal inflammation during OTM on the other hand significantly augmented the extent of DRR, relative expression of inflammatory/osteoclast marker genes, blood leukocyte level and periodontal osteoclast activity. In addition, contrary to previous studies, we observed a significant increase in tooth movement velocity. Although accelerated tooth movement would be favourable for orthodontic treatment, our results suggest that orthodontic interventions should only be performed after successful systematic periodontal therapy and paused in case of recurrent active inflammation. Copyright © 2016 Elsevier GmbH. All rights reserved.

Involvement of Trigeminal Transition Zone and Laminated Subnucleus Caudalis in Masseter Muscle Hypersensitivity Associated with Tooth Inflammation

PubMed Central

Shimizu, Kohei; Matsumoto, Kunihito; Noma, Noboru; Matsuura, Shingo; Ohara, Kinuyo; Komiya, Hiroki; Watase, Tetsuro; Ogiso, Bunnai; Tsuboi, Yoshiyuki; Shinoda, Masamichi; Hatori, Keisuke; Nakaya, Yuka; Iwata, Koichi

2014-01-01

A rat model of pulpitis/periapical periodontitis was used to study mechanisms underlying extraterritorial enhancement of masseter response associated with tooth inflammation. Periapical bone loss gradually increased and peaked at 6 weeks after complete Freund’s adjuvant (CFA) application to the upper molar tooth pulp (M1). On day 3, the number of Fos-immunoreactive (IR) cells was significantly larger in M1 CFA rats compared with M1 vehicle (veh) rats in the trigeminal subnucleus interpolaris/caudalis transition zone (Vi/Vc). The number of Fos-IR cells was significantly larger in M1 CFA and masseter (Mass) capsaicin applied (M1 CFA/Mass cap) rats compared with M1 veh/Mass veh rats in the contralateral Vc and Vi/Vc. The number of phosphorylated extracellular signal-regulated kinase (pERK)-IR cells was significantly larger in M1 CFA/Mass cap and M1 veh/Mass cap rats compared to Mass-vehicle applied rats with M1 vehicle or CFA in the Vi/Vc. Pulpal CFA application caused significant increase in the number of Fos-IR cells in the Vi/Vc but not Vc on week 6. The number of pERK-IR cells was significantly lager in the rats with capsaicin application to the Mass compared to Mass-vehicle treated rats after pulpal CFA- or vehicle-application. However, capsaicin application to the Mass did not further affect the number of Fos-IR cells in the Vi/Vc in pulpal CFA-applied rats. The digastric electromyographic (d-EMG) activity after Mass-capsaicin application was significantly increased on day 3 and lasted longer at 6 weeks after pulpal CFA application, and these increase and duration were significantly attenuated by i.t. PD98059, a MEK1 inhibitor. These findings suggest that Vi/Vc and Vc neuronal excitation is involved in the facilitation of extraterritorial hyperalgesia for Mass primed with periapical periodontitis or acute pulpal-inflammation. Furthermore, phosphorylation of ERK in the Vi/Vc and Vc play pivotal roles in masseter hyperalgesia after pulpitis or periapical periodontitis. PMID:25279551

Derivation of soil screening thresholds to protect chisel-toothed kangaroo rat from uranium mine waste in northern Arizona

USGS Publications Warehouse

Hinck, Jo E.; Linder, Greg L.; Otton, James K.; Finger, Susan E.; Little, Edward E.; Tillitt, Donald E.

2013-01-01

Chemical data from soil and weathered waste material samples collected from five uranium mines north of the Grand Canyon (three reclaimed, one mined but not reclaimed, and one never mined) were used in a screening-level risk analysis for the Arizona chisel-toothed kangaroo rat (Dipodomys microps leucotis); risks from radiation exposure were not evaluated. Dietary toxicity reference values were used to estimate soil-screening thresholds presenting risk to kangaroo rats. Sensitivity analyses indicated that body weight critically affected outcomes of exposed-dose calculations; juvenile kangaroo rats were more sensitive to the inorganic constituent toxicities than adult kangaroo rats. Species-specific soil-screening thresholds were derived for arsenic (137 mg/kg), cadmium (16 mg/kg), copper (1,461 mg/kg), lead (1,143 mg/kg), nickel (771 mg/kg), thallium (1.3 mg/kg), uranium (1,513 mg/kg), and zinc (731 mg/kg) using toxicity reference values that incorporate expected chronic field exposures. Inorganic contaminants in soils within and near the mine areas generally posed minimal risk to kangaroo rats. Most exceedances of soil thresholds were for arsenic and thallium and were associated with weathered mine wastes.

The effects of local administration of Zoledronate solution on the tooth movement and periodontal ligament.

PubMed

Liu, Chang; Sun, Xinhua; Chen, Yuanping; Hu, Min; Liang, Tang

2002-07-01

To investigate the effects of local administration of Zoledronate solution on the tooth movement and periodontal ligament. Orthodontic tooth movement of upper first molar was performed in 42 rats with coil spring. Zoledronate solution was injected into the palatal submucosal area adjacent to the left upper first molar in experimental group 3 days prior to the use of the appliance. In control group, same amount of 0.9% NaCl solution was injected into the palatal submucosal area adjacent to the left and right upper first molar. The injection was applied every third day. The application of mesial force lasted 0.3, 7, 14, 21 days respectively. After the rats were sacrificed, the distance of tooth movement was measured. Sections were stained and then observed with microscope. 1. The distance of tooth movement in the experimental group was significantly smaller than that in the control group. 2. The number of osteoclast on the pressure side in the experiment group was significantly smaller than that in the control group through the experimental period, but there was no distinct difference between experimental group and control group (except for 14 days) for the number of odontoclast in interradicular area. 3. The osteoclasts and odontoclasts were the main target cell of Zoledronate in periodontal tissue. Zoledronate may be a useful agent for anchorage control and reducing the number of osteoclast on pressure side of alveolar bone.

Characterisation of secretory calcium-binding phosphoprotein-proline-glutamine-rich 1: a novel basal lamina component expressed at cell-tooth interfaces.

PubMed

Moffatt, Pierre; Wazen, Rima M; Dos Santos Neves, Juliana; Nanci, Antonio

2014-12-01

Functional genomic screening of the rat enamel organ (EO) has led to the identification of a number of secreted proteins expressed during the maturation stage of amelogenesis, including amelotin (AMTN) and odontogenic ameloblast-associated (ODAM). In this study, we characterise the gene, protein and pattern of expression of a related protein called secretory calcium-binding phosphoprotein-proline-glutamine-rich 1 (SCPPPQ1). The Scpppq1 gene resides within the secretory calcium-binding phosphoprotein (Scpp) cluster. SCPPPQ1 is a highly conserved, 75-residue, secreted protein rich in proline, leucine, glutamine and phenylalanine. In silico data mining has revealed no correlation to any known sequences. Northern blotting of various rat tissues suggests that the expression of Scpppq1 is restricted to tooth and associated tissues. Immunohistochemical analyses show that the protein is expressed during the late maturation stage of amelogenesis and in the junctional epithelium where it localises to an atypical basal lamina at the cell-tooth interface. This discrete localisation suggests that SCPPPQ1, together with AMTN and ODAM, participates in structuring the basal lamina and in mediating attachment of epithelia cells to mineralised tooth surfaces.

Colocalization of dentin matrix protein 1 and dentin sialoprotein at late stages of rat molar development.

PubMed

Baba, Otto; Qin, Chunlin; Brunn, Jan C; Wygant, James N; McIntyre, Bradley W; Butler, William T

2004-10-01

Dentin matrix protein 1 (DMP1) and dentin sialophosphoprotein (DSPP) are acidic proteins found in the extracellular matrices of bones and teeth. Recent data from gene knockouts, along with those of gene mutations, indicate that these two phosphoproteins are critical for bone and tooth development and/or maintenance. However, the precise functions of the two proteins have not been elucidated. In order to gain insights into their functions in tooth formation, we performed systematic, comparative investigations on the immunolocalization of DMP1 and dentin sialoprotein (DSP, a cleaved fragment of DSPP), using the rat first molar at different developmental stages as a model. Immunohistochemistry (IHC) was performed with specific, monoclonal antibodies against the COOH-terminal fragments of DMP1 and against DSP. In 1-day- and 1-week-old rats, weak immunoreactions for DMP1 were observed in dentinal tubules while stronger reactions for DSP were seen in the tubules and predentin. In rats older than 2 weeks, immunoreactions for DMP1 were found in dentinal tubules, predentin and odontoblasts. In 5-week- and 8-week-old rats, strong immunoreactions for DMP1 were widely distributed in odontoblasts and predentin. The distribution pattern of DSP was strikingly similar to that of DMP1 after 2 weeks and the localization of each was distinctly different from that of bone sialoprotein (BSP). The unique colocalization of DMP1 and DSPP in tooth development suggests that the two proteins play complementary and/or synergistic roles in formation and maintenance of healthy teeth.

Expression of Pleiotrophin in the Prostate is Androgen Regulated and it Functions as an Autocrine Regulator of Mesenchyme and Cancer Associated Fibroblasts and as a Paracrine Regulator of Epithelia

PubMed Central

Orr, Brigid; Vanpoucke, Griet; Grace, O Cathal; Smith, Lee; Anderson, Richard A; Riddick, Antony CP; Franco, Omar E; Hayward, Simon W; Thomson, Axel A

2011-01-01

BACKGROUND Androgens and paracrine signaling from mesenchyme/stroma regulate development and disease of the prostate, and gene profiling studies of inductive prostate mesenchyme have identified candidate molecules such as pleiotrophin (Ptn). METHODS Ptn transcripts and protein were localized by in situ and immunohistochemistry and Ptn mRNA was quantitated by Northern blot and qRT-PCR. Ptn function was examined by addition of hPTN protein to rat ventral prostate organ cultures, primary human fetal prostate fibroblasts, prostate cancer associated fibroblasts, and BPH1 epithelia. RESULTS During development, Ptn transcripts and protein were expressed in ventral mesenchymal pad (VMP) and prostatic mesenchyme. Ptn was localized to mesenchyme surrounding ductal epithelial tips undergoing branching morphogenesis, and was located on the surface of epithelia. hPTN protein stimulated branching morphogenesis and stromal and epithelial proliferation, when added to rat VP cultures, and also stimulated growth of fetal human prostate fibroblasts, prostate cancer associated fibroblasts, and BPH1 epithelia. PTN mRNA was enriched in patient-matched normal prostate fibroblasts versus prostate cancer associated fibroblasts. PTN also showed male enriched expression in fetal human male urethra versus female, and between wt male and ARKO male mice. Transcripts for PTN were upregulated by testosterone in fetal human prostate fibroblasts and organ cultures of female rat VMP. Ptn protein was increased by testosterone in organ cultures of female rat VMP and in rat male urethra compared to female. CONCLUSIONS Our data suggest that in the prostate Ptn functions as a regulator of both mesenchymal and epithelial proliferation, and that androgens regulate Ptn levels. Prostate 71:305–317, 2011. © 2010 Wiley-Liss, Inc. PMID:20812209

A gene network model accounting for development and evolution of mammalian teeth

PubMed Central

Salazar-Ciudad, Isaac; Jernvall, Jukka

2002-01-01

Generation of morphological diversity remains a challenge for evolutionary biologists because it is unclear how an ultimately finite number of genes involved in initial pattern formation integrates with morphogenesis. Ideally, models used to search for the simplest developmental principles on how genes produce form should account for both developmental process and evolutionary change. Here we present a model reproducing the morphology of mammalian teeth by integrating experimental data on gene interactions and growth into a morphodynamic mechanism in which developing morphology has a causal role in patterning. The model predicts the course of tooth-shape development in different mammalian species and also reproduces key transitions in evolution. Furthermore, we reproduce the known expression patterns of several genes involved in tooth development and their dynamics over developmental time. Large morphological effects frequently can be achieved by small changes, according to this model, and similar morphologies can be produced by different changes. This finding may be consistent with why predicting the morphological outcomes of molecular experiments is challenging. Nevertheless, models incorporating morphology and gene activity show promise for linking genotypes to phenotypes. PMID:12048258

An Evo-Devo perspective on ever-growing teeth in mammals and dental stem cell maintenance

PubMed Central

Renvoisé, Elodie; Michon, Frederic

2014-01-01

A major challenge for current evolutionary and developmental biology research is to understand the evolution of morphogenesis and the mechanisms involved. Teeth are well suited for the investigation of developmental processes. In addition, since teeth are composed of hard-mineralized tissues, primarily apatite, that are readily preserved, the evolution of mammals is well documented through their teeth in the fossil record. Hypsodonty, high crowned teeth with shallow roots, and hypselodonty, ever-growing teeth, are convergent innovations that have appeared multiple times since the mammalian radiation 65 million years ago, in all tooth categories (incisors, canines, premolars, and molars). A shift to hypsodonty, or hypselodonty, during mammalian evolution is often, but not necessarily, associated with increasingly abrasive diet during important environmental change events. Although the evolution of hypsodonty and hypselodonty is considered to be the result of heterochrony of development, little has been known about the exact developmental mechanisms at the origin of these morphological traits. Developmental biologists have been intrigued by the mechanism of hypselodonty since it requires the maintenance of continuous crown formation during development via stem cell niche activity. Understanding this mechanism may allow bioengineered tooth formation in humans. Hypsodonty and hypselodonty are thus examples of phenotypic features of teeth that have both impacts in understanding the evolution of mammals and holds promise for human tooth bioengineering. PMID:25221518

Decreased expression of monocarboxylate transporter 1 and 4 in the branching airway epithelium of nitrofen-induced congenital diaphragmatic hernia.

PubMed

Takahashi, Toshiaki; Friedmacher, Florian; Zimmer, Julia; Puri, Prem

2016-06-01

Monocarboxylate transporters (MCTs) are crucial for the maintenance of intracellular pH homeostasis in developing fetal lungs. MCT1/4 is strongly expressed by epithelial airway cells throughout lung branching morphogenesis. Functional inhibition of MCT1/4 in fetal rat lung explants has been shown to result in airway defects similar to pulmonary hypoplasia (PH) in congenital diaphragmatic hernia (CDH). We hypothesized that pulmonary expression of MCT1/4 is decreased during lung branching morphogenesis in the nitrofen model of CDH-associated PH. Timed-pregnant rats received nitrofen or vehicle on gestational day 9 (D9). Fetuses were harvested on D15, D18, and D21, and divided into control and nitrofen-exposed group. Pulmonary gene expression levels of MCT1/4 were analyzed by qRT-PCR. Immunofluorescence staining for MCT1/4 was combined with E-cadherin in order to evaluate protein expression in branching airway tissue. Relative mRNA levels of MCT1/4 were significantly reduced in lungs of nitrofen-exposed fetuses on D15, D18, and D21 compared to controls. Confocal laser scanning microscopy confirmed markedly decreased immunofluorescence of MCT1/4 in distal bronchial and primitive alveolar epithelium of nitrofen-exposed fetuses on D15, D18, and D21 compared to controls. Decreased expression of MCT1/4 in distal airway epithelium may disrupt lung branching morphogenesis and thus contribute to the development of PH in the nitrofen-induced CDH model. Copyright © 2016 Elsevier Inc. All rights reserved.

Effects of corticopuncture (CP) and low-level laser therapy (LLLT) on the rate of tooth movement and root resorption in rats using micro-CT evaluation.

PubMed

Suzuki, Selly Sayuri; Garcez, Aguinaldo Silva; Reese, Patricia Oblitas; Suzuki, Hideo; Ribeiro, Martha Simões; Moon, Won

2018-05-01

The aim of this study was to compare the rate of tooth displacement, quantity of root resorption, and alveolar bone changes in five groups: corticopuncture (CP), low-level laser therapy (LLLT), CP combined with LLLT (CP + LLLT), control (C), and negative control (NC). A total of 60 half-maxilla from 30 male Wistar rats (10 weeks old) were divided randomly into five groups: three (CP, LLLT, and CP + LLLT) test groups with different stimulation for accelerated-tooth-movement (ATM), one control (C) group, and one negative control (NC) group with no tooth movement. Nickel-titanium coil springs with 50 g of force were tied from the upper left and right first molars to micro-implants placed behind the maxillary incisors. For the CP and CP + LLLT groups, two perforations in the palate and one mesially to the molars were performed. For the LLLT and CP + LLLT groups, GaAlAs diode laser was applied every other day for 14 days (810 nm, 100 mW, 15 s). The tooth displacements were measured directly from the rat's mouth and indirectly from microcomputer (micro-CT) tomographic images. Bone responses at the tension and compression sites and root resorption were analyzed from micro-CT images. The resulting alveolar bone responses were evaluated by measuring bone mineral density (BMD), bone volume fraction (BV/TV), and trabecular thickness (TbTh). Root resorption crater volumes were measured on both compression and tension sides of mesial and distal buccal roots. The tooth displacement in the CP + LLLT group was the greatest when measured clinically, followed by the CP, LLLT, and control groups (C and NC), respectively (p <0.05). The tooth movements measured from micro-CT images showed statistically higher displacement in the CP and CP + LLLT groups compared to the LLLT and control groups. The BMD, BV/TV, and TbTh values were lower at the compression side and higher at the tension side for all three test groups compared to the control group. The root resorption crater volume of the distal buccal root was higher in the control group, followed by CP, LLLT, and CP + LLLT, mostly at the compression site. Combining corticopuncture and low-level laser therapy (CP + LLLT) produced more tooth displacement and less root resorption at the compression side. The combined technique also promoted higher alveolar bone formation at the tension side.

Demineralised human dentine matrix stimulates the expression of VEGF and accelerates the bone repair in tooth sockets of rats.

PubMed

Reis-Filho, Cláudio R; Silva, Elisângela R; Martins, Adalberto B; Pessoa, Fernanda F; Gomes, Paula V N; de Araújo, Mariana S C; Miziara, Melissa N; Alves, José B

2012-05-01

In this study we investigated the possible use of human demineralised dentine matrix (DHDM), obtained from the extracted teeth, as bone graft material and evaluated the expression of vascular endothelial growth factor (VEGF) induced by this material in the healing process of tooth sockets of rats. To evaluate bone regeneration and expression of VEGF induced by DHDM, thirty-two male Wistar rats weighing approximately 200 g were used. After maxillary second molar extraction, the left sockets were filled with DHDM and the right sockets were naturally filled by blood clot (control). The animals were sacrificed at 3, 7, 14 and 21 days after surgery and upper maxillaries were processed for histological, morphometric and immunohistochemical analyses. DHDM was used to evaluate the mechanical effect of bone graft material into sockets. Expression of VEGF was determined by immunohistochemistry in all groups. Our results demonstrated a significant increase in the newly formed bone tissue in sockets of 7, 14 and 21 days and a significant increase in VEGF expression at days 7 and 14 on treated sockets. Our results showed that DHDM increases the expression of VEGF and accelerates the healing process in rats tooth sockets, by stimulating bone deposition and also vessels formation. These results suggest that DHDM has osteoinductive/osteoconductive potential and may represent an efficient grafting material on guided bone regeneration. Copyright © 2011 Elsevier Ltd. All rights reserved.

Pantoprazole, a proton pump inhibitor, increases orthodontic tooth movement in rats.

PubMed

Shirazi, Mohsen; Alimoradi, Houman; Kheirandish, Yasaman; Etemad-Moghadam, Shahroo; Alaeddini, Mojgan; Meysamie, Alipasha; Fatahi Meybodi, Seyed Amir Reza; Dehpour, Ahmad Reza

2014-06-01

Pantoprazole, is a proton pump inhibitor (PPI) prescribed for the treatment of upper gastrointestinal disorders, which in high doses has been suggested to decrease calcium absorption leading to hypocalcaemia and therefore osteoporosis. The aim of this study was to assess whether pantoprazol, could alter the rate of orthodontic tooth movement (OTM) in rats. A time course study was established using 72 rats which were divided into six groups of 12 samples each (four: vehicle; eight: pantoprazole + vehicle). Pantoprazole at a dose of 200 mg/kg suspended in carboxymethyl cellulose (0.25 percent) was administered by a gastric tube. The upper incisors and first molars were ligated by a 5 mm nickel-titanium closed-coil spring to deliver an initial force of 60 g. Animals were euthanized two weeks after orthodontic treatment followed by assessment of tooth movement and histomorphometric evaluation of the detached maxillae. Lateral skull radiographs were obtained once a week, starting from the first day to the 6(th) week of the study. OTM and bone density data were analyzed using independent sample t-test and repeated measures ANOVA. No significant changes in OTM measurements and optical density were observed in vehicle-receiving animals during the study (P=0.994). OTM was significantly increased after six weeks pantoprazole therapy which continued until the 7(th) week of the experiment (P=0.007). Optical density significantly increased in the pantoprazole-treated rats after six weeks. Long term PPI therapy at high doses could lead to osteoporosis and enhanced OTM.

The Influence of Acetyl Salicylic Acid (Aspirin) and Acetaminophen on Clinical and Histologic Aspects of Orthodontic Tooth Movement

DTIC Science & Technology

1988-05-01

in the rate of tooth movement associated with orthodontic mechanics. Locally high concentrations of prostaglandins appear to accelerate orthodontic...highly localized . One of the many roles that prostaglandins are believed to perform in cellular metabolism is that of inflammatory response mediator...histologic effects of locally injected prostaglandins, Yamasaki found that rat molars receiving no orthodontic force, displayed an increase in bone

Requirement of alveolar bone formation for eruption of rat molars

PubMed Central

Wise, Gary E.; He, Hongzhi; Gutierrez, Dina L.; Ring, Sherry; Yao, Shaomian

2011-01-01

Tooth eruption is a localized event that requires a dental follicle (DF) to regulate the resorption of alveolar bone to form an eruption pathway. During the intra-osseous phase of eruption, the tooth moves through this pathway. The mechanism or motive force that propels the tooth through this pathway is controversial but many studies have shown that alveolar bone growth at the base of the crypt occurs during eruption. To determine if this bone growth (osteogenesis) was causal, experiments were designed in which the expression of an osteogenic gene in the DF, bone morphogenetic protein-6 (BMP6), was inhibited by injection of the 1st mandibular molar of the rat with an siRNA targeted against BMP6. The injection was followed by electroporation to promote uptake of the siRNA. In 45 first molars injected, eruption either was delayed or completely inhibited (7 molars). In the impacted molars, an eruption pathway formed but bone growth at the base of the crypt was greatly reduced as compared to the erupted first molar controls. These studies show that alveolar bone growth at the base of the crypt is required for tooth eruption and that BMP6 may be an essential gene for promoting this growth. PMID:21896048

An ancient dental gene set governs development and continuous regeneration of teeth in sharks.

PubMed

Rasch, Liam J; Martin, Kyle J; Cooper, Rory L; Metscher, Brian D; Underwood, Charlie J; Fraser, Gareth J

2016-07-15

The evolution of oral teeth is considered a major contributor to the overall success of jawed vertebrates. This is especially apparent in cartilaginous fishes including sharks and rays, which develop elaborate arrays of highly specialized teeth, organized in rows and retain the capacity for life-long regeneration. Perpetual regeneration of oral teeth has been either lost or highly reduced in many other lineages including important developmental model species, so cartilaginous fishes are uniquely suited for deep comparative analyses of tooth development and regeneration. Additionally, sharks and rays can offer crucial insights into the characters of the dentition in the ancestor of all jawed vertebrates. Despite this, tooth development and regeneration in chondrichthyans is poorly understood and remains virtually uncharacterized from a developmental genetic standpoint. Using the emerging chondrichthyan model, the catshark (Scyliorhinus spp.), we characterized the expression of genes homologous to those known to be expressed during stages of early dental competence, tooth initiation, morphogenesis, and regeneration in bony vertebrates. We have found that expression patterns of several genes from Hh, Wnt/β-catenin, Bmp and Fgf signalling pathways indicate deep conservation over ~450 million years of tooth development and regeneration. We describe how these genes participate in the initial emergence of the shark dentition and how they are redeployed during regeneration of successive tooth generations. We suggest that at the dawn of the vertebrate lineage, teeth (i) were most likely continuously regenerative structures, and (ii) utilised a core set of genes from members of key developmental signalling pathways that were instrumental in creating a dental legacy redeployed throughout vertebrate evolution. These data lay the foundation for further experimental investigations utilizing the unique regenerative capacity of chondrichthyan models to answer evolutionary, developmental, and regenerative biological questions that are impossible to explore in classical models. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Effects of Low-Intensity Pulsed Ultrasound on Orthodontic Tooth Movement and Orthodontically Induced Inflammatory Root Resorption in Ovariectomized Osteoporotic Rats.

PubMed

Dahhas, Feras Y; El-Bialy, Tarek; Afify, Ahmed R; Hassan, Ali H

2016-03-01

This study investigated the effects of low-intensity pulsed ultrasound (LIPUS) on orthodontic tooth movement (OTM) and orthodontically induced inflammatory root resorption (OIRR) in ovariectomized osteoporotic rats. Forty-eight 28-d-old female Wistar rats were divided into ovariectomized and intact groups. In both groups, animals were left untreated; treated with 50 g mesially directed orthodontic force on the maxillary first molars using nickel-titanium closed-coil springs for 28 d; or treated with the same orthodontic protocol along with a 20-min LIPUS application on alternate days for 28 d. Extent of OTM and amount of OIRR of mesial roots were measured on three-dimensionally reconstructed micro-computed tomography images. Ovariectomy increased OIRR (p < 0.05). LIPUS reduced root volumetric loss regardless of ovariectomy status (p < 0.05); only ovariectomized animals had decreased OTM (p < 0.05). LIPUS normalizes OTM and attenuates OIRR in ovariectomized osteoporotic rats. It may therefore be beneficial in women with postmenopausal osteoporosis. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

A novel autosomal-recessive mutation, whitish chalk-like teeth, resembling amelogenesis imperfecta, maps to rat chromosome 14 corresponding to human 4q21.

PubMed

Masuyama, Taku; Miyajima, Katsuhiro; Ohshima, Hayato; Osawa, Masaru; Yokoi, Norihide; Oikawa, Toshihiro; Taniguchi, Kazuyuki

2005-12-01

A rat mutant, whitish chalk-like teeth (wct), with white, chalk-like abnormal incisors, was discovered and morphologically and genetically characterized. The mutant rats showed tooth enamel defects that were similar to those of human amelogenesis imperfecta. The wct mutation was found to disturb the morphological transition of ameloblasts from secretory to maturation stages and to induce cyst formation. This mutation also disturbs the transfer of iron into the enamel, resulting in the whitish chalk-like incisors. A genetic linkage study indicated that the wct locus maps to a specific interval of rat chromosome 14 between D14Got13 and D14Wox2. Interestingly, the human chromosomal region orthologous to wct, a 5.5-Mb interval in human chromosome 4q21, is a critical region for the locus of human amelogenesis imperfecta AIH2. These results strongly suggest that this wct mutant is a useful model for the identification of genes responsible for amelogenesis imperfecta and molecular mechanisms of tooth development.

Expression of Sproutys and SPREDs is decreased during lung branching morphogenesis in nitrofen-induced pulmonary hypoplasia.

PubMed

Friedmacher, Florian; Gosemann, Jan-Hendrik; Fujiwara, Naho; Takahashi, Hiromizu; Hofmann, Alejandro; Puri, Prem

2013-11-01

Pulmonary hypoplasia (PH) is a life-threatening condition associated with congenital diaphragmatic hernia (CDH), characterized by defective lung development. Sproutys and Sprouty-related proteins (SPREDs) play a key role in lung branching morphogenesis through modification of epithelial-mesenchymal interactions. During the pseudoglandular stage, Sproutys are highly expressed in distal airway epithelium, while SPREDs within the surrounding mesenchyme. Sprouty2/4 knockouts show severe defects in branching morphogenesis with reduced number of distal airways. SPRED-1 and SPRED-2 are strongly expressed in regions of new airway formation, highlighting their important function in branching pattern. We hypothesized that expression of Sprouty2, Sprouty4, SPRED-1 and SPRED-2 is decreased during lung branching morphogenesis in nitrofen-induced PH. Timed-pregnant rats received either nitrofen or vehicle on E9.5. On E15.5 (n = 16), fetal lungs were micro-dissected and divided into controls and PH, while on E18.5 (n = 24) groups were: control, PH without CDH [CDH(-)], and PH with CDH [CDH(+)]. Pulmonary gene expression levels of Sprouty2, Sprouty4, SPRED-1 and SPRED-2 were analyzed by qRT-PCR. Immunohistochemistry was performed to evaluate protein expression/distribution. On E18.5, relative mRNA expression levels of Sprouty2, Sprouty4, SPRED-1 and SPRED-2 were significantly decreased in CDH(-) and CDH(+) groups compared to controls (P < 0.05). Immunoreactivity of Sprouty2, Sprouty4, SPRED-1 and SPRED-2 was markedly diminished on E18.5 in nitrofen-induced PH. Decreased expression of Sproutys and SPREDs during the terminal pseudoglandular stage may disrupt lung branching morphogenesis by interfering with epithelial-mesenchymal interactions contributing to PH.

Nicotinic Receptor Alpha7 Expression during Tooth Morphogenesis Reveals Functional Pleiotropy

PubMed Central

Rogers, Scott W.; Gahring, Lorise C.

2012-01-01

The expression of nicotinic acetylcholine receptor (nAChR) subtype, alpha7, was investigated in the developing teeth of mice that were modified through homologous recombination to express a bi-cistronic IRES-driven tau-enhanced green fluorescent protein (GFP); alpha7GFP) or IRES-Cre (alpha7Cre). The expression of alpha7GFP was detected first in cells of the condensing mesenchyme at embryonic (E) day E13.5 where it intensifies through E14.5. This expression ends abruptly at E15.5, but was again observed in ameloblasts of incisors at E16.5 or molar ameloblasts by E17.5–E18.5. This expression remains detectable until molar enamel deposition is completed or throughout life as in the constantly erupting mouse incisors. The expression of alpha7GFP also identifies all stages of innervation of the tooth organ. Ablation of the alpha7-cell lineage using a conditional alpha7Cre×ROSA26-LoxP(diphtheria toxin A) strategy substantially reduced the mesenchyme and this corresponded with excessive epithelium overgrowth consistent with an instructive role by these cells during ectoderm patterning. However, alpha7knock-out (KO) mice exhibited normal tooth size and shape indicating that under normal conditions alpha7 expression is dispensable to this process. The function of ameloblasts in alpha7KO mice is altered relative to controls. High resolution micro-computed tomography analysis of adult mandibular incisors revealed enamel volume of the alpha7KO was significantly reduced and the organization of enamel rods was altered relative to controls. These results demonstrate distinct and varied spatiotemporal expression of alpha7 during tooth development, and they suggest that dysfunction of this receptor would have diverse impacts upon the adult organ. PMID:22666322

Automated Image Analysis of Lung Branching Morphogenesis from Microscopic Images of Fetal Rat Explants

PubMed Central

Rodrigues, Pedro L.; Rodrigues, Nuno F.; Duque, Duarte; Granja, Sara; Correia-Pinto, Jorge; Vilaça, João L.

2014-01-01

Background. Regulating mechanisms of branching morphogenesis of fetal lung rat explants have been an essential tool for molecular research. This work presents a new methodology to accurately quantify the epithelial, outer contour, and peripheral airway buds of lung explants during cellular development from microscopic images. Methods. The outer contour was defined using an adaptive and multiscale threshold algorithm whose level was automatically calculated based on an entropy maximization criterion. The inner lung epithelium was defined by a clustering procedure that groups small image regions according to the minimum description length principle and local statistical properties. Finally, the number of peripheral buds was counted as the skeleton branched ends from a skeletonized image of the lung inner epithelia. Results. The time for lung branching morphometric analysis was reduced in 98% in contrast to the manual method. Best results were obtained in the first two days of cellular development, with lesser standard deviations. Nonsignificant differences were found between the automatic and manual results in all culture days. Conclusions. The proposed method introduces a series of advantages related to its intuitive use and accuracy, making the technique suitable to images with different lighting characteristics and allowing a reliable comparison between different researchers. PMID:25250057

Effects of the GaAlAs diode laser (780 nm) on the periodontal tissues during orthodontic tooth movement in diabetes rats: histomorphological and immunohistochemical analysis.

PubMed

Gomes, Mônica Fernandes; da Graças Vilela Goulart, Maria; Giannasi, Lilian Chrystiane; Hiraoka, Cybelle Mori; de Fátima Santana Melo, Gabriela; de Sousa, Aretha Graziela Vilela; Nóbrega, Celestino José Prudente; Zangaro, Renato Amaro; Salgado, Miguel Angel Castillo

2017-09-01

The purposes of the present study are to assess the effects of the GaAlAs diode laser on the periodontal tissues and to investigate its action on the alveolar bone remodeling process during orthodontic tooth movement in normoglycemic and diabetic rats. Sixty adult male Wistar rats were divided into four groups of 15 rats: normoglycemic (N), diabetic (D), laser-normoglycemic (LN), and laser-diabetic (LD) rats. Diabetes mellitus was induced by a single intravenous injection of 40 mg/kg monohydrated alloxan. The orthodontically moved tooth underwent a force magnitude of 20 cN. The laser irradiation with a continuous emission of a 780-nm wavelength, an output power of 20 mW, and a fiber probe with a spot size of 0.04 cm in diameter and an area of 0.00126 cm 2 were used. Moreover, an energy density of 640 J/cm 2 was applied in an exposition time of 40 s. Histomorphological and immunohistochemical analysis was performed. The photobiomodulation (PBM) strongly stimulated the periodontal tissue response, establishing mainly the balance between the bone formation and resorption. Intense inflammatory cell infiltration and extensive loss of bone tissue were mainly found in the D group from 14 days. The number of osteopontin-positive osteocytes was significantly greater in the LN group, followed by the LD, especially at 7 and 14 days, whereas osteoprotegerin-positive osteoblasts were significantly higher in the LN and LD groups than in the N and D groups, respectively, in all periods. The PBM strongly stimulated the alveolar bone remodeling and favored the continuous reorganization of the soft periodontal tissues, leading to the maintenance and integrity of the periodontal microstructure under orthodontic force, especially in uncontrolled diabetic rats.

Orthodontic Forces Induce the Cytoprotective Enzyme Heme Oxygenase-1 in Rats.

PubMed

Suttorp, Christiaan M; Xie, Rui; Lundvig, Ditte M S; Kuijpers-Jagtman, Anne Marie; Uijttenboogaart, Jasper Tom; Van Rheden, René; Maltha, Jaap C; Wagener, Frank A D T G

2016-01-01

Orthodontic forces disturb the microenvironment of the periodontal ligament (PDL), and induce craniofacial bone remodeling which is necessary for tooth movement. Unfortunately, orthodontic tooth movement is often hampered by ischemic injury and cell death within the PDL (hyalinization) and root resorption. Large inter-individual differences in hyalinization and root resorption have been observed, and may be explained by differential protection against hyalinization. Heme oxygenase-1 (HO-1) forms an important protective mechanism by breaking down heme into the strong anti-oxidants biliverdin/bilirubin and the signaling molecule carbon monoxide. These versatile HO-1 products protect against ischemic and inflammatory injury. We postulate that orthodontic forces induce HO-1 expression in the PDL during experimental tooth movement. Twenty-five 6-week-old male Wistar rats were used in this study. The upper three molars at one side were moved mesially using a Nickel-Titanium coil spring, providing a continuous orthodontic force of 10 cN. The contralateral side served as control. After 6, 12, 72, 96, and 120 h groups of rats were killed. On parasagittal sections immunohistochemical staining was performed for analysis of HO-1 expression and quantification of osteoclasts. Orthodontic force induced a significant time-dependent HO-1 expression in mononuclear cells within the PDL at both the apposition- and resorption side. Shortly after placement of the orthodontic appliance HO-1 expression was highly induced in PDL cells but dropped to control levels within 72 h. Some osteoclasts were also HO-1 positive but this induction was shown to be independent of time- and mechanical stress. It is tempting to speculate that differential induction of tissue protecting- and osteoclast activating genes in the PDL determine the level of bone resorption and hyalinization and, subsequently, "fast" and "slow" tooth movers during orthodontic treatment.

Periodontal response to orthodontic tooth movement in diabetes-induced rats with or without periodontal disease.

PubMed

Ferreira, Camila Lopes; da Rocha, Vinicius Clemente; da Silva Ursi, Weber José; De Marco, Andrea Carvalho; Santamaria, Milton; Santamaria, Mauro Pedrine; Jardini, Maria Aparecida Neves

2018-03-01

Systemic conditions can influence orthodontic tooth movement. This study evaluates histologic periodontal responses to orthodontic tooth movement in diabetes-induced rats with or without periodontal disease. Forty Wistar rats were divided according their systemic condition (SC) into diabetic (D) and non-diabetic (ND) groups. Each group was subdivided into control (C), orthodontic tooth movement (OM), ligature-induced periodontitis (P) and ligature-induced periodontitis with orthodontic movement (P+OM) groups. Diabetes mellitus (DM) was induced with alloxan monohydrate, and after 30 days, the P group received a cotton ligature around their first lower molar crown. An orthodontic device was placed in OM and P+OM groups for 7 days, and the animals were then euthanized. Differences in OM between D and ND groups were not significant (6.87± 3.55 mm and 6.81 ± 3.28 mm, respectively), but intragroup analysis revealed statistically significant differences between the P+OM groups for both SCs. Bone loss was greater in the D group (0.16 ± 0.07 mm 2 ) than in the ND group (0.10 ± 0.03 mm 2 ). In intragroup analysis of the D condition, the P+OM group differed statistically from the other groups, while in the ND condition, the P+OM group was different from the C and OM groups. There was a statistically significant difference in bone density between D and ND conditions (18.03 ± 8.09% and 22.53 ± 7.72%) in the C, P, and P+OM groups. DM has deleterious effects on bone density and bone loss in the furcation region. These effects are maximized when associated with ligature-induced periodontitis with orthodontic movement. © 2018 American Academy of Periodontology.

TNF-α Upregulates Expression of BMP-2 and BMP-3 Genes in the Rat Dental Follicle – Implications for Tooth Eruption

PubMed Central

Yao, Shaomian; Prpic, Veronica; Pan, Fenghui; Wise, Gary E.

2011-01-01

The dental follicle appears to regulate both the alveolar bone resorption and bone formation needed for tooth eruption. Tumor necrosis factor-alpha ( TNF-α) gene expression is maximally upregulated at postnatal day 9 in the rat dental follicle of the 1st mandibular molar, a time that correlates with rapid bone growth at the base of the tooth crypt, as well as a minor burst of osteoclastogenesis. TNF-α expression is correlated with the expression of bone morphogenetic protein-2 (BMP-2), a molecule expressed in the dental follicle that can promote bone formation. Because BMP-2 signaling may be augmented by bone morphogenetic protein-3 (BMP-3), it was the objective of this study to determine 1) if the dental follicle expresses BMP-3 and 2) if TNF-α stimulates the dental follicle cells to express BMP-2 and BMP-3. Dental follicles were collected from different postnatal ages of rat pups. Dental follicle cells were incubated with TNF-α to study its dosage and time-course effects on gene expression of BMP-2 and BMP-3, as determined by real-time RT-PCR. Next, immunostaining was conducted to confirm if the protein was synthesized and ELISA of the conditioned medium was conducted to determine if BMP-2 was secreted. We found that BMP-3 expression is correlated with the expression of TNF-α in the dental follicle and TNF-α significantly increased BMP-2 and BMP-3 expression in vitro. Immunostaining and ELISA showed that BMP-2 and BMP-3 were synthesized and secreted. This study suggests that TNF-α can upregulate the expression of bone formation genes that may be needed for tooth eruption. PMID:20067418

Orthodontic Forces Induce the Cytoprotective Enzyme Heme Oxygenase-1 in Rats

PubMed Central

Suttorp, Christiaan M.; Xie, Rui; Lundvig, Ditte M. S.; Kuijpers-Jagtman, Anne Marie; Uijttenboogaart, Jasper Tom; Van Rheden, René; Maltha, Jaap C.; Wagener, Frank A. D. T. G.

2016-01-01

Orthodontic forces disturb the microenvironment of the periodontal ligament (PDL), and induce craniofacial bone remodeling which is necessary for tooth movement. Unfortunately, orthodontic tooth movement is often hampered by ischemic injury and cell death within the PDL (hyalinization) and root resorption. Large inter-individual differences in hyalinization and root resorption have been observed, and may be explained by differential protection against hyalinization. Heme oxygenase-1 (HO-1) forms an important protective mechanism by breaking down heme into the strong anti-oxidants biliverdin/bilirubin and the signaling molecule carbon monoxide. These versatile HO-1 products protect against ischemic and inflammatory injury. We postulate that orthodontic forces induce HO-1 expression in the PDL during experimental tooth movement. Twenty-five 6-week-old male Wistar rats were used in this study. The upper three molars at one side were moved mesially using a Nickel-Titanium coil spring, providing a continuous orthodontic force of 10 cN. The contralateral side served as control. After 6, 12, 72, 96, and 120 h groups of rats were killed. On parasagittal sections immunohistochemical staining was performed for analysis of HO-1 expression and quantification of osteoclasts. Orthodontic force induced a significant time-dependent HO-1 expression in mononuclear cells within the PDL at both the apposition- and resorption side. Shortly after placement of the orthodontic appliance HO-1 expression was highly induced in PDL cells but dropped to control levels within 72 h. Some osteoclasts were also HO-1 positive but this induction was shown to be independent of time- and mechanical stress. It is tempting to speculate that differential induction of tissue protecting- and osteoclast activating genes in the PDL determine the level of bone resorption and hyalinization and, subsequently, “fast” and “slow” tooth movers during orthodontic treatment. PMID:27486402

Three consecutive days of application of LED therapy is necessary to inhibit experimentally induced root resorption in rats: a microtomographic study.

PubMed

Higashi, Dayla Thyeme; Andrello, Avacir Casanova; Tondelli, Pedro Marcelo; de Oliveira Toginho Filho, Dari; de Paula Ramos, Solange

2017-01-01

Previous studies have suggested that phototherapy may modulate orthodontic tooth movement and the incidence of root resorption. We aimed to identify a minimal dose-response relationship to LED therapy with regard to orthodontic tooth movement (OTM) and root resorption in rats. Forty-eight male Wistar rats were divided into six groups with equal and random distribution: control (C) no intervention; three daily LED irradiation (CLED); submitted only to OTM (RR); OTM and LED irradiation on the first day (LED1); OTM and two LED irradiation on the first and second days (LED2); and OTM and three LED irradiation on the first, second, and third days (LED3). Orthodontic appliance was installed in groups RR, LED1, LED2, and LED3 to promote OTM. Animals from groups CLED, LED1, LED2, and LED3 received LED therapy (940 nm, 4 J, 4 J/cm2) according to each group of treatment. After 7 days, all the animals were sacrificed. The jaws were fixed and scanned with microtomography (micro-CT). The micro-CT images were reconstructed on 2D and 3D models. These models were used to identify and measure root resorption number and dimensions (diameter, depth, and volume). The distance between the first and second molars was used to verify tooth displacement. The results showed that LED3 group had significantly lower number of root resorption. The root resorption dimensions (diameter and depth) had no significant differences among the experimental groups. LED3 group had significant tooth displacement in relation to C and CLED groups. In conclusion, three daily LED therapy doses are required to inhibit root resorption after appliance of orthodontic forces.

In utero and lactational exposure to vinclozolin and genistein induces genomic changes in the rat mammary gland.

PubMed

El Sheikh Saad, H; Toullec, A; Vacher, S; Pocard, M; Bieche, I; Perrot-Applanat, M

2013-02-01

Exposure to low doses of environmental estrogens such as bisphenol A and genistein (G) alters mammary gland development. The effects of environmental anti-androgens, such as the fungicide vinclozolin (V), on mammary gland morphogenesis are unknown. We previously reported that perinatal exposure to G, V, and the GV combination causes histological changes in the mammary gland during the peripubertal period, suggesting alterations to the peripubertal hormone response. We now investigate whether perinatal exposure to these compounds alters the gene expression profiles of the developing glands to identify the dysregulated signaling pathways and the underlying mechanisms. G, V, or GV (1 mg/kg body weight per day) was added to diet of Wistar rats, from conception to weaning; female offspring mammary glands were collected at postnatal days (PNDs) 35 and 50. Genes displaying differential expression and belonging to different functional categories were validated by quantitative PCR and immunocytochemistry. At PND35, G had little effect; the slight changes noted were in genes related to morphogenesis. The changes following exposure to V concerned the functional categories associated with development (Cldn1, Krt17, and Sprr1a), carbohydrate metabolism, and steroidogenesis. The GV mixture upregulated genes (Krt17, Pvalb, and Tnni2) involved in muscle development, indicating effects on myoepithelial cells during mammary gland morphogenesis. Importantly, at PND50, cycling females exposed to GV showed an increase in the expression of genes (Csn2, Wap, and Elf5) related to differentiation, consistent with the previously reported abnormal lobuloalveolar development previously described. Thus, perinatal exposure to GV alters the mammary gland hormone response differently at PND35 (puberty) and in animals with established cycles.

Lithium chloride attenuates root resorption during orthodontic tooth movement in rats.

PubMed

Wang, Yu; Gao, Shang; Jiang, Huan; Lin, Peng; Bao, Xingfu; Zhang, Zhimin; Hu, Min

2014-02-01

Root resorption is a common side effect of orthodontic treatment. In the current study, lithium chloride (LiCl), a Wnt signaling activator, was examined to determine its effect on root resorption. In total, 10 Sprague Dawley rats were randomly allocated into the experimental group (EG) and control group (CG). Each group consisted of five subjects. By using closed nickel-titanium coil springs, a 50-g force was applied between the upper incisors and the maxillary right first molars in order to mimic orthodontic biomechanics in the EG and CG for 14 days. During the 14 days, the EG rats were gavage-fed 200 mg/kg LiCl every 48 h. Next, digital radiographs were captured using a micro-computational tomography scanner. The movement of the maxillary first molars and the root resorption area ratio were measured electronically on the digital radiographs. The outcomes were analyzed using ANOVA. Following 14 days of experimental force application, all rats had spaces of varying sizes between the first and second right maxillary molars. The average distance measured in the CG was slightly higher than in the EG, however, the difference was not found to be statistically significant (P=0.224). Root resorption craters were observed in the groups following the experiment. Rough cementum areas were observed on the mesial surface of the distobuccal and distopalatal roots. The mean root resorption area ratio of CG was significantly greater than EG (P<0.05). Results of the present study indicate that LiCl can attenuate orthodontically induce root resorption during orthodontic tooth movement. The effect of LiCl on tooth movement is insignificant.

Effect of different doses of hexavalent chromium on mandibular growth and tooth eruption in juvenile Wistar rats.

PubMed

De Lucca, Romina C; Dutrey, Patricio L; Villarino, Mariano E; Ubios, Angela M

2009-07-01

Not only workers employed at industrial plants are exposed to intoxication with the element they manipulate, the population at large is also at risk of suffering health problems caused by contaminating wastes inadequately treated for their safe disposal. As a result certain toxic substances, such as hexavalent chromium,has reached the general population including children. The present study sought to evaluate the effect of intoxication with hexavalent chromium on body and mandibular growth and tooth eruption in suckling Wistar rats. Potassium dichromate was administered by gavage in a dose of 6.25 or 12.5mg/kg body weight (b.w.) to one of the two groups of 4-day-old Wistar rats during 10 days. Our results showed that the effects of chromium are dose-dependent. Morphometric studies of body growth showed lower body weight in both experimental groups and shorter tail length in animals receiving 12.5mg/kg b.w. dose of chromium, compared with controls. All parameters of mandibular growth were lower in the experimental group receiving 12.5mg/kg b.w. of chromium. Differences in tooth eruption were observed at the level of the first molar in animals receiving 12.5mg/kg and of the second molar in those receiving 6.25mg/kg b.w. of chromium. Chromium was found to affect all the studied parameters.

A Novel Chitosan-γPGA Polyelectrolyte Complex Hydrogel Promotes Early New Bone Formation in the Alveolar Socket Following Tooth Extraction

PubMed Central

Chang, Hao-Hueng; Wang, Yin-Lin; Chiang, Yu-Chih; Chen, Yen-Liang; Chuang, Yu-Horng; Tsai, Shang-Jye; Heish, Kuo-Huang; Lin, Feng-Huei; Lin, Chun-Pin

2014-01-01

A novel chitosan-γPGA polyelectrolyte complex hydrogel (C-PGA) has been developed and proven to be an effective dressing for wound healing. The purpose of this study was to evaluate if C-PGA could promote new bone formation in the alveolar socket following tooth extraction. An animal model was proposed using radiography and histomorphology simultaneously to analyze the symmetrical sections of Wistar rats. The upper incisors of Wistar rats were extracted and the extraction sockets were randomly treated with gelatin sponge, neat chitosan, C-PGA, or received no treatment. The extraction sockets of selected rats from each group were evaluated at 1, 2, 4, or 6 wk post-extraction. The results of radiography and histopathology indicated that the extraction sockets treated with C-PGA exhibited lamellar bone formation (6.5%) as early as 2 wk after the extraction was performed. Moreover, the degree of new bone formation was significantly higher (P < 0.05) in the extraction sockets treated with C-PGA at 6 wk post-extraction than that in the other study groups. In this study, we demonstrated that the proposed animal model involving symmetrical sections and simultaneous radiography and histomorphology evaluation is feasible. We also conclude that the novel C-PGA has great potential for new bone formation in the alveolar socket following tooth extraction. PMID:24658174

Distribution of syndecan-1 protein in developing mouse teeth

PubMed Central

Filatova, Anna; Pagella, Pierfrancesco; Mitsiadis, Thimios A.

2014-01-01

Syndecan-1 is a cell surface proteoglycan involved in the regulation of various biological processes such as proliferation, migration, condensation and differentiation of cells, intercellular communication, and morphogenesis. The extracellular domain of syndecan-1 can bind to extracellular matrix components and signaling molecules, while its intracellular domain interacts with cytoskeletal proteins, thus allowing the transfer of information about extracellular environment changes into the cell that consequently affect cellular behavior. Although previous studies have shown syndecan-1 expression during precise stages of tooth development, there is no equivalent study regrouping the expression patterns of syndecan-1 during all stages of odontogenesis. Here we examined the distribution of syndecan-1 protein in embryonic and post-natal developing mouse molars and incisors. Syndecan-1 distribution in mesenchymal tissues such as dental papilla and dental follicle was correlated with proliferating events and its expression was often linked to stem cell niche territories. Syndecan-1 was also expressed in mesenchymal cells that will differentiate into the dentin producing odontoblasts, but not in differentiated functional odontoblasts. In the epithelium, syndecan-1 was detected in all cell layers, by the exception of differentiated ameloblasts that form the enamel. Furthermore, syndecan-1 was expressed in osteoblast precursors and osteoclasts of the alveolar bone that surrounds the developing tooth germs. Taken together these results show the dynamic nature of syndecan-1 expression during odontogenesis and suggest its implication in various processes of tooth development and homeostasis. PMID:25642191

Dental developmental abnormalities in a patient with subtelomeric 7q36 deletion syndrome may confirm a novel role for the SHH gene☆

PubMed Central

Linhares, Natália D.; Svartman, Marta; Salgado, Mauro Ivan; Rodrigues, Tatiane C.; da Costa, Silvia S.; Rosenberg, Carla; Valadares, Eugênia R.

2013-01-01

Studies in mice demonstrated that the Shh gene is crucial for normal development of both incisors and molars, causing a severe retardation in tooth growth, which leads to abnormal placement of the tooth in the jaw and disrupted tooth morphogenesis. In humans the SHH gene is located on chromosome 7q36. Defects in its protein or signaling pathway may cause holoprosencephaly spectrum, a disorder in which the developing forebrain fails to correctly separate into right and left hemispheres and that can be manifested in microforms such as single maxillary central incisor. A novel role for this gene in the developing human primary dentition was recently demonstrated. We report a 12-year old boy with a de novo 7q36.1-qter deletion characterized by high-resolution karyotyping, oligonucleotide aCGH and FISH. His phenotype includes intellectual disability, non-verbal communication, hypospadia, partial sacral agenesis and absence of coccyx, which are distinctive features of the syndrome and mainly correlated with the MNX1, HTR5A and EN2 genes. No microforms of holoprosencephaly spectrum were observed; but the patient had diastema and dental developmental abnormalities, such as conical, asymmetric and tapered inferior central incisors. The dental anomalies are reported herein for the first time in subtelomeric 7q36 deletion syndrome and may confirm clinically a novel role for the SHH gene in dental development. PMID:25606385

The effect of caffeine on orthodontic tooth movement in rats

PubMed Central

Shirazi, Mohsen; Vaziri, Hamed; Salari, Behzad; Motahhari, Pouria; Etemad-Moghadam, Shahroo; Dehpour, Ahmad Reza

2017-01-01

Objective(s): to determine the effect of different doses of caffeine on orthodontic tooth movement (OTM) in rats. Materials and Methods: Forty male 250-300 g Sprague-Dawley rats were randomly divided into four groups of ten animals each and received 0 (control), 1 g/l, 2 g/l and 3 g/l caffeine in tap water for 3 days. Orthodontic appliances were ligated between the maxillary first molars and incisors on the 4th day of the study period. All rats were sacrificed after 2 weeks of treatment after which OTM was measured. Hematoxylin/eosin-stained sections of the molars were prepared and the mesial roots were examined for resorption-lacunae depth and osteoclast number. ANOVA was used for statistical analysis (P<0.05). Results: A significant decrease in OTM was observed only in the 2 g/l (P=0.043) and 3 g/l (P<0.01) caffeine-receiving rats compared to the control animals. Osteoclast counts and resorption-lacunae depths demonstrated significant differences between each of the caffeine groups and control rats (P<0.05). None of the variables showed significant differences between the caffeine groups (P>0.05). Conclusion: According to our findings, one of the effects of caffeine consumption during orthodontic treatment in rats was decreased root resorption. Additionally, concentrations of 2 g/l and 3 g/l inhibited OTM which seems to be due to its influence on osteoclast numbers. PMID:28392897

High-Frequency, Low-Intensity Pulsed Ultrasound Enhances Alveolar Bone Healing of Extraction Sockets in Rats: A Pilot Study.

PubMed

Kang, Kyung Lhi; Kim, Eun-Cheol; Park, Joon Bong; Heo, Jung Sun; Choi, Yumi

2016-02-01

Most studies of the beneficial effects of low-intensity pulsed ultrasound (LIPUS) on bone healing have used frequencies between 1.0 and 1.5 MHz. However, after consideration of ultrasound wave characteristics and depth of target tissue, higher-frequency LIPUS may have been more effective on superficially positioned alveolar bone. We investigated this hypothesis by applying LIPUS (frequency, 3.0 MHz; intensity, 30 mW/cm(2)) on shaved right cheeks over alveolar bones of tooth extraction sockets in rats for 10 min/d for 2 wk after tooth extraction; the control group (left cheek of the same rats) did not receive LIPUS treatment. Compared with the control group, the LIPUS group manifested more new bone growth inside the sockets on histomorphometric analysis (maximal difference = 2.5-fold on the seventh day after extraction) and higher expressions of osteogenesis-related mRNAs and proteins than the control group did. These findings indicate that 3.0-MHz LIPUS could enhance alveolar bone formation and calcification in rats. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Vibration paradox in orthodontics: Anabolic and catabolic effects

PubMed Central

Alikhani, Mani; Alansari, Sarah; Hamidaddin, Mohammad A.; Sangsuwon, Chinapa; Alyami, Bandar; Thirumoorthy, Soumya N.; Oliveira, Serafim M.; Nervina, Jeanne M.

2018-01-01

Vibration in the form of High Frequency Acceleration (HFA) is anabolic on the craniofacial skeleton in the absence of inflammation. Orthodontic forces trigger an inflammation-dependent catabolic cascade that is crucial for tooth movement. It is unknown what effect HFA has on alveolar bone if applied during orthodontic treatment. The objectives of this study are to examine the effect of HFA on the rate of tooth movement and alveolar bone, and determine the mechanism by which HFA affects tooth movement. Adult Sprague Dawley rats were divided to control, orthodontic force alone (OTM), and different experimental groups that received the same orthodontic forces and different HFA regimens. Orthodontic tooth movement was assessed when HFA parameters, frequency, acceleration, duration of exposure, and direct or indirect application were varied. We found that HFA treatment significantly enhanced the inflammation-dependent catabolic cascade during orthodontic tooth movement. HFA treatment increased inflammatory mediators and osteoclastogenesis, and decreased alveolar bone density during orthodontic tooth movement. Each of the HFA variables produced significant changes in the rate of tooth movement and the effect was PDL-dependent. This is the first report that HFA enhances inflammation-dependent catabolic cascades in bone. The clinical implications of our study are highly significant, as HFA can be utilized to enhance the rate of orthodontic tooth movement during the catabolic phase of treatment and subsequently be utilized to enhance retention during the anabolic remodeling phase after orthodontic forces are removed. PMID:29734391

Epimorphin regulates bile duct formation via effects on mitosis orientation in rat liver epithelial stem-like cells.

PubMed

Zhou, Junnian; Zhao, Lei; Qin, Lipeng; Wang, Jing; Jia, Yali; Yao, Hailei; Sang, Chen; Hu, Qinghua; Shi, Shuangshuang; Nan, Xue; Yue, Wen; Zhuang, Fengyuan; Yang, Chun; Wang, Yunfang; Pei, Xuetao

2010-03-17

Understanding how hepatic precursor cells can generate differentiated bile ducts is crucial for studies on epithelial morphogenesis and for development of cell therapies for hepatobiliary diseases. Epimorphin (EPM) is a key morphogen for duct morphogenesis in various epithelial organs. The role of EPM in bile duct formation (DF) from hepatic precursor cells, however, is not known. To address this issue, we used WB-F344 rat epithelial stem-like cells as model for bile duct formation. A micropattern and a uniaxial static stretch device was used to investigate the effects of EPM and stress fiber bundles on the mitosis orientation (MO) of WB cells. Immunohistochemistry of liver tissue sections demonstrated high EPM expression around bile ducts in vivo. In vitro, recombinant EPM selectively induced DF through upregulation of CK19 expression and suppression of HNF3alpha and HNF6, with no effects on other hepatocytic genes investigated. Our data provide evidence that EPM guides MO of WB-F344 cells via effects on stress fiber bundles and focal adhesion assembly, as supported by blockade EPM, beta1 integrin, and F-actin assembly. These blockers can also inhibit EPM-induced DF. These results demonstrate a new biophysical action of EPM in bile duct formation, during which determination of MO plays a crucial role.

Dysbindin-1, WAVE2 and Abi-1 form a complex that regulates dendritic spine formation.

PubMed

Ito, H; Morishita, R; Shinoda, T; Iwamoto, I; Sudo, K; Okamoto, K; Nagata, K

2010-10-01

Genetic variations in dysbindin-1 (dystrobrevin-binding protein-1) are one of the most commonly reported variations associated with schizophrenia. As schizophrenia could be regarded as a neurodevelopmental disorder resulting from abnormalities of synaptic connectivity, we attempted to clarify the function of dysbindin-1 in neuronal development. We examined the developmental change of dysbindin-1 in rat brain by western blotting and found that a 50 kDa isoform is highly expressed during the embryonic stage, whereas a 40 kDa one is detected at postnatal day 11 and increased thereafter. Immunofluorescent analyses revealed that dysbindin-1 is enriched at the spine-like structure of primary cultured rat hippocampal neurons. We identified WAVE2, but not N-WASP, as a binding partner for dysbindin-1. We also found that Abi-1, a binding molecule for WAVE2 involved in spine morphogenesis, interacts with dysbindin-1. Although dysbindin-1, WAVE2 and Abi-1 form a ternary complex, dysbindin-1 promoted the binding of WAVE2 to Abi-1. RNA interference-mediated knockdown of dysbindin-1 led to the generation of abnormally elongated immature dendritic protrusions. The present results indicate possible functions of dysbindin-1 at the postsynapse in the regulation of dendritic spine morphogenesis through the interaction with WAVE2 and Abi-1.

Bone marrow-derived stromal cells are more beneficial cell sources for tooth regeneration compared with adipose-derived stromal cells.

PubMed

Ye, Lanfeng; Chen, Lin; Feng, Fan; Cui, Junhui; Li, Kaide; Li, Zhiyong; Liu, Lei

2015-10-01

Tooth loss is presently a global epidemic and tooth regeneration is thought to be a feasible and ideal treatment approach. Choice of cell source is a primary concern in tooth regeneration. In this study, the odontogenic differentiation potential of two non-dental-derived stem cells, adipose-derived stromal cells (ADSCs) and bone marrow-derived stromal cells (BMSCs), were evaluated both in vitro and in vivo. ADSCs and BMSCs were induced in vitro in the presence of tooth germ cell-conditioned medium (TGC-CM) prior to implantation into the omentum majus of rats, in combination with inactivated dentin matrix (IDM). Real-time quantitative polymerase chain reaction (RT-qPCR) was used to detect the mRNA expression levels of odontogenic-related genes. Immunofluorescence and immunohistochemical assays were used to detect the protein levels of odontogenic-specific genes, such as DSP and DMP-1 both in vitro and in vivo. The results suggest that both ADSCs and BMSCs have odontogenic differentiation potential. However, the odontogenic potential of BMSCs was greater compared with ADSCs, showing that BMSCs are a more appropriate cell source for tooth regeneration. © 2015 International Federation for Cell Biology.

Reversed palatal perforation by upper incisors in ageing blind mole-rats (Spalax ehrenbergi)

PubMed Central

ZURI, I.; TERKEL, J.

2001-01-01

Blind mole-rats (Spalax ehrenbergi) are fossorial solitary rodents that present striking morphological, physiological and behavioural adaptations to the subterranean environment in which they live. Previous studies have shown that mole-rats are specialised in tooth-digging. The rapid eruption-rate of their incisors has evolved to compensate for their excessive wear by excavation. Males use their incisors more than females for digging and fighting, and their rate of incisor eruption is significantly more rapid than in females. Since mole-rats use their incisors for digging throughout the year, we suggest that continuous mechanical pressure on their oral tissues concentrated at the apical sites of the upper incisors leads to cell and tissue fatigue. We provide evidence for 5 stages of palatal perforation by the upper incisors at their apical sites, with maximum perforation characterising aged males. Interspecies comparisons with 7 other fossorial and semi-fossorial rodent species, and with beavers, which expose their incisors to enormous mechanical pressure, revealed that this palatal perforation is unique to the male mole-rat. We suggest that while the fast eruption rate of incisors in the mole-rat compensates for the rapid wear resulting from digging, evolutionary adaptation to continuous tooth-digging is still ongoing, since the physical pressure of digging at the apical sites of the upper incisors leads to tissue destruction, breakage of the palatal bone and possibly to death, as a result of maxillary inflammation. PMID:11760890

Use of new targeted cancer therapies in children: effects on dental development and risk of jaw osteonecrosis: a review.

PubMed

Hernandez, Magali; Phulpin, Bérengère; Mansuy, Ludovic; Droz, Dominique

2017-05-01

New targeted cancer therapies such as bisphosphonates, denosumab, and bevacizumab are routinely used in adult for the past decades. Their introduction into pediatric medicine is more recent that means there is a paucity of data on long-term effects on dental development and on the risk of osteonecrosis of jaw. This study aimed to outline adverse effects of new targeted cancer therapies on oral cavity including dental abnormalities observed in pediatric population treated with these molecules and the risk of osteonecrosis of the jaw (ONJ). The impact of bisphosphonates and denosumab on bone remodeling (inhibition of osteoclasts) could interfere with teeth exfoliation and eruption processes, causing a tooth eruption delay. This hypothesis was confirmed, bisphosphonate-treated rats presented tooth eruption delay, and bisphosphonate therapy was associated with a mean delay of 1.67 years in tooth eruption in children with osteogenesis imperfecta. Another study showed that the inhibition of RANK/RANKL by denosumab was associated with a lack of tooth eruption in animals. Several animal studies reported that bisphosphonate could also induce dental abnormalities including defective amelogenesis and dentinogenesis in rats, but there is no evidence of such effects in children; only one case of enamel hypoplasia in a child treated for idiopathic arterial calcification with bisphosphate was reported. To date, there has been no reported case of ONJ in children treated with bisphosphonates, denosumab, or bevacizumab. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Cell wall accumulation of fluorescent proteins derived from a trans-Golgi cisternal membrane marker and paramural bodies in interdigitated Arabidopsis leaf epidermal cells.

PubMed

Akita, Kae; Kobayashi, Megumi; Sato, Mayuko; Kutsuna, Natsumaro; Ueda, Takashi; Toyooka, Kiminori; Nagata, Noriko; Hasezawa, Seiichiro; Higaki, Takumi

2017-01-01

In most dicotyledonous plants, leaf epidermal pavement cells develop jigsaw puzzle-like shapes during cell expansion. The rapid growth and complicated cell shape of pavement cells is suggested to be achieved by targeted exocytosis that is coordinated with cytoskeletal rearrangement to provide plasma membrane and/or cell wall materials for lobe development during their morphogenesis. Therefore, visualization of membrane trafficking in leaf pavement cells should contribute an understanding of the mechanism of plant cell morphogenesis. To reveal membrane trafficking in pavement cells, we observed monomeric red fluorescent protein-tagged rat sialyl transferases, which are markers of trans-Golgi cisternal membranes, in the leaf epidermis of Arabidopsis thaliana. Quantitative fluorescence imaging techniques and immunoelectron microscopic observations revealed that accumulation of the red fluorescent protein occurred mostly in the curved regions of pavement cell borders and guard cell ends during leaf expansion. Transmission electron microscopy observations revealed that apoplastic vesicular membrane structures called paramural bodies were more frequent beneath the curved cell wall regions of interdigitated pavement cells and guard cell ends in young leaf epidermis. In addition, pharmacological studies showed that perturbations in membrane trafficking resulted in simple cell shapes. These results suggested possible heterogeneity of the curved regions of plasma membranes, implying a relationship with pavement cell morphogenesis.

Patterning by heritage in mouse molar row development.

PubMed

Prochazka, Jan; Pantalacci, Sophie; Churava, Svatava; Rothova, Michaela; Lambert, Anne; Lesot, Hervé; Klein, Ophir; Peterka, Miroslav; Laudet, Vincent; Peterkova, Renata

2010-08-31

It is known from paleontology studies that two premolars have been lost during mouse evolution. During mouse mandible development, two bud-like structures transiently form that may represent rudimentary precursors of the lost premolars. However, the interpretation of these structures and their significance for mouse molar development are highly controversial because of a lack of molecular data. Here, we searched for typical tooth signaling centers in these two bud-like structures, and followed their fate using molecular markers, 3D reconstructions, and lineage tracing in vitro. Transient signaling centers were indeed found to be located at the tips of both the anterior and posterior rudimentary buds. These centers expressed a similar set of molecular markers as the "primary enamel knot" (pEK), the signaling center of the first molar (M1). These two transient signaling centers were sequentially patterned before and anterior to the M1 pEK. We also determined the dynamics of the M1 pEK, which, slightly later during development, spread up to the field formerly occupied by the posterior transient signaling center. It can be concluded that two rudimentary tooth buds initiate the sequential development of the mouse molars and these have previously been mistaken for early stages of M1 development. Although neither rudiment progresses to form an adult tooth, the posterior one merges with the adjacent M1, which may explain the anterior enlargement of the M1 during mouse family evolution. This study highlights how rudiments of lost structures can stay integrated and participate in morphogenesis of functional organs and help in understanding their evolution, as Darwin suspected long ago.

Stereological determination of the volume of the rat hemimandible tissues.

PubMed

Silva, M A; Merzel, J

2001-07-01

Rodent incisors are useful models to study the development and behavior of dental and periodontal tissues. Some studies require three-dimensional reconstructions of the tooth but none of the described methods yield actual volumetric data. Unlike the rat lower incisors the hemimandible can be easily isolated and its volume was determined by Cavalieri's geometrical principle. This method associated with point-counting volumetry was used to calculate the volume of the structures found in that bone mainly those related to the lower incisor. For 172 g male rats the mean volume of the hemimandible was 182.7 mm(3), statistically not different from 184.9 mm(3) the mean volume of the same hemimandibles determined by Archimedes' principle. The coefficients of error (CE) of Cavalieri's estimates for the hemimandible, incisor as a whole (the tooth itself, odontogenic region and periodontium) and bone tissue were less than 0.04. For the incisor individual tissues the CEs were usually above 0.05, however their calculated volumes are probably not different from the actual ones. The data for incisors and their periodontal tissues and for bone, because of continuous growth of these structures, are meaningful only for rats of the same gender, strain and weight range. Copyright 2001 Wiley-Liss, Inc.

Type IV collagen is a novel DEJ biomarker that is reduced by radiotherapy.

PubMed

McGuire, J D; Gorski, J P; Dusevich, V; Wang, Y; Walker, M P

2014-10-01

The dental basement membrane (BM) is composed of collagen types IV, VI, VII, and XVII, fibronectin, and laminin and plays an inductive role in epithelial-mesenchymal interactions during tooth development. The BM is degraded and removed during later-stage tooth morphogenesis; however, its original position defines the location of the dentin-enamel junction (DEJ) in mature teeth. We recently demonstrated that type VII collagen is a novel component of the inner enamel organic matrix layer contiguous with the DEJ. Since it is frequently co-expressed with and forms functional complexes with type VII collagen, we hypothesized that type IV collagen should also be localized to the DEJ in mature human teeth. To identify collagen IV, we first evaluated defect-free erupted teeth from various donors. To investigate a possible stabilizing role, we also evaluated extracted teeth exposed to high-dose radiotherapy--teeth that manifest post-radiotherapy DEJ instability. We now show that type IV collagen is a component within the morphological DEJ of posterior and anterior teeth from individuals aged 18 to 80 yr. Confocal microscopy revealed that immunostained type IV collagen was restricted to the 5- to 10-µm-wide optical DEJ, while collagenase treatment or previous in vivo tooth-level exposure to > 60 Gray irradiation severely reduced immunoreactivity. This assignment was confirmed by Western blotting with whole-tooth crown and enamel extracts. Without reduction, type IV collagen contained macromolecular α-chains of 225 and 250 kDa. Compositionally, our results identify type IV collagen as the first macromolecular biomarker of the morphological DEJ of mature teeth. Given its network structure and propensity to stabilize the dermal-epidermal junction, we propose that a collagen-IV-enriched DEJ may, in part, explain its well-known fracture toughness, crack propagation resistance, and stability. In contrast, loss of type IV collagen may represent a biochemical rationale for the DEJ instability observed following oral cancer radiotherapy. © International & American Associations for Dental Research.

Type IV Collagen is a Novel DEJ Biomarker that is Reduced by Radiotherapy

PubMed Central

McGuire, J.D.; Gorski, J.P.; Dusevich, V.; Wang, Y.; Walker, M.P.

2014-01-01

The dental basement membrane (BM) is composed of collagen types IV, VI, VII, and XVII, fibronectin, and laminin and plays an inductive role in epithelial-mesenchymal interactions during tooth development. The BM is degraded and removed during later-stage tooth morphogenesis; however, its original position defines the location of the dentin-enamel junction (DEJ) in mature teeth. We recently demonstrated that type VII collagen is a novel component of the inner enamel organic matrix layer contiguous with the DEJ. Since it is frequently co-expressed with and forms functional complexes with type VII collagen, we hypothesized that type IV collagen should also be localized to the DEJ in mature human teeth. To identify collagen IV, we first evaluated defect-free erupted teeth from various donors. To investigate a possible stabilizing role, we also evaluated extracted teeth exposed to high-dose radiotherapy – teeth that manifest post-radiotherapy DEJ instability. We now show that type IV collagen is a component within the morphological DEJ of posterior and anterior teeth from individuals aged 18 to 80 yr. Confocal microscopy revealed that immunostained type IV collagen was restricted to the 5- to 10-µm-wide optical DEJ, while collagenase treatment or previous in vivo tooth-level exposure to > 60 Gray irradiation severely reduced immunoreactivity. This assignment was confirmed by Western blotting with whole-tooth crown and enamel extracts. Without reduction, type IV collagen contained macromolecular α-chains of 225 and 250 kDa. Compositionally, our results identify type IV collagen as the first macromolecular biomarker of the morphological DEJ of mature teeth. Given its network structure and propensity to stabilize the dermal-epidermal junction, we propose that a collagen-IV-enriched DEJ may, in part, explain its well-known fracture toughness, crack propagation resistance, and stability. In contrast, loss of type IV collagen may represent a biochemical rationale for the DEJ instability observed following oral cancer radiotherapy. PMID:25146181

Ectoderm-targeted overexpression of the glucocorticoid receptor induces hypohidrotic ectodermal dysplasia.

PubMed

Cascallana, Jose Luis; Bravo, Ana; Donet, Eva; Leis, Hugo; Lara, Maria Fernanda; Paramio, Jesús M; Jorcano, José L; Pérez, Paloma

2005-06-01

Hypohidrotic ectodermal dysplasia is a human syndrome defined by maldevelopment of one or more ectodermal-derived tissues, including the epidermis and cutaneous appendices, teeth, and exocrine glands. The molecular bases of this pathology converge in a dysfunction of the transcription factor nuclear factor of the kappa-enhancer in B cells (NF-kappaB), which is essential to epithelial homeostasis and development. A number of mouse models bearing disruptions in NF-kappaB signaling have been reported to manifest defects in ectodermal derivatives. In ectoderm-targeted transgenic mice overexpressing the glucocorticoid receptor (GR) [keratin 5 (K5)-GR mice], the NF-kappaB activity is greatly decreased due to functional antagonism between GR and NF-kappaB. Here, we report that K5-GR mice exhibit multiple epithelial defects in hair follicle, tooth, and palate development. Additionally, these mice lack Meibomian glands and display underdeveloped sweat and preputial glands. These phenotypic features appear to be mediated specifically by ligand-activated GR because the synthetic analog dexamethasone induced similar defects in epithelial morphogenesis, including odontogenesis, in wild-type mice. We have focused on tooth development in K5-GR mice and found that an inhibitor of steroid synthesis partially reversed the abnormal phenotype. Immunostaining revealed reduced expression of the inhibitor of kappaB kinase subunits, IKKalpha and IKKgamma, and diminished p65 protein levels in K5-GR embryonic tooth, resulting in a significantly reduced kappaB-binding activity. Remarkably, altered NF-kappaB activity elicited by GR overexpression correlated with a dramatic decrease in the protein levels of DeltaNp63 in tooth epithelia without affecting Akt, BMP4, or Foxo3a. Given that many of the 170 clinically distinct ectodermal dysplasia syndromes still remain without cognate genes, deciphering the molecular mechanisms of this mouse model with epithelial NF-kappaB and p63 dysfunction may provide important clues to understanding the basis of other ectodermal dysplasia syndromes.

Localization of type IV collagen a 1 to a 6 chains in basement membrane during mouse molar germ development.

PubMed

Nagai, N; Nakano, K; Sado, Y; Naito, I; Gunduz, M; Tsujigiwa, H; Nagatsuka, H; Ninomiya, Y; Siar, C H

2001-10-01

The dental basement membrane (BM) putatively mediates epithelial-mesenchymal interactions during tooth morphogenesis and cytodifferentiation. Type IV collagen alpha chains, a major network-forming protein of the dental BM, was studied and results disclosed distinct expression patterns at different stages of mouse molar germ development. At the dental placode and bud stage, the BM of the oral epithelium expressed alpha 1, alpha 2, alpha 5 and alpha 6 chains while the gubernaculum dentis, in addition to the above four chains, also expressed a 4 chain. An asymmetrical expression for alpha 4, alpha 5 and alpha 6 chains was observed at the bud stage. At the early bell stage, the BM associated with the inner enamel epithelium (IEE) of molar germ expressed alpha 1, alpha 2 and alpha 4 chains while the BM of the outer enamel epithelium (OEE) expressed only alpha 1 and a 2 chains. With the onset of dentinogenesis, the collagen a chain profile of the IEE BM gradually disappeared. Howeverfrom the early to late bell stage, the gubernaculum dentis consistently expressed alpha 1, alpha 2, alpha 5 and a 6 chains resembling fetal oral mucosa. These findings suggest that stage- and position-specific distribution of type IV collagen alpha subunits occur during molar germ development and that these changes are essential for molar morphogenesis and cytodifferentiation.

Transcriptional response of rat frontal cortex following acute In Vivo exposure to the pyrethroid insecticides permethrin and deltamethrin

PubMed Central

Harrill, Joshua A; Li, Zhen; Wright, Fred A; Radio, Nicholas M; Mundy, William R; Tornero-Velez, Rogelio; Crofton, Kevin M

2008-01-01

Background Pyrethroids are neurotoxic pesticides that interact with membrane bound ion channels in neurons and disrupt nerve function. The purpose of this study was to characterize and explore changes in gene expression that occur in the rat frontal cortex, an area of CNS affected by pyrethroids, following an acute low-dose exposure. Results Rats were acutely exposed to either deltamethrin (0.3 – 3 mg/kg) or permethrin (1 – 100 mg/kg) followed by collection of cortical tissue at 6 hours. The doses used range from those that cause minimal signs of intoxication at the behavioral level to doses well below apparent no effect levels in the whole animal. A statistical framework based on parallel linear (SAM) and isotonic regression (PIR) methods identified 95 and 53 probe sets as dose-responsive. The PIR analysis was most sensitive for detecting transcripts with changes in expression at the NOAEL dose. A sub-set of genes (Camk1g, Ddc, Gpd3, c-fos and Egr1) was then confirmed by qRT-PCR and examined in a time course study. Changes in mRNA levels were typically less than 3-fold in magnitude across all components of the study. The responses observed are consistent with pyrethroids producing increased neuronal excitation in the cortex following a low-dose in vivo exposure. In addition, Significance Analysis of Function and Expression (SAFE) identified significantly enriched gene categories common for both pyrethroids, including some relating to branching morphogenesis. Exposure of primary cortical cell cultures to both compounds resulted in an increase (~25%) in the number of neurite branch points, supporting the results of the SAFE analysis. Conclusion In the present study, pyrethroids induced changes in gene expression in the frontal cortex near the threshold for decreases in ambulatory motor activity in vivo. The penalized regression methods performed similarly in detecting dose-dependent changes in gene transcription. Finally, SAFE analysis of gene expression data identified branching morphogenesis as a biological process sensitive to pyrethroids and subsequent in vitro experiments confirmed this predicted effect. The novel findings regarding pyrethroid effects on branching morphogenesis indicate these compounds may act as developmental neurotoxicants that affect normal neuronal morphology. PMID:19017407

Evaluation of laser photobiomodulation (λ 780 nm) on repair of dental replantation in rats

NASA Astrophysics Data System (ADS)

Bastos de Carvalho, Fabíola; Vasconcelos, Rebeca M.; Santos, Laila; dos Santos Barbosa, Artur F.; Aguiar, Marcio C.; Cangussu, Maria Cristina T.; Pinheiro, Antônio Luiz B.; Pedreira Ramalho, Luciana M.

2014-02-01

Up to date the success of tooth replantation is still limited. The majority of the teeth is lost due to progressive external root resorption. The aim of this study was to assess, histologically, the effect of laser photobiomodulation on repair after tooth replantation. Sixty Wistar Albinus rats had the right upper incisor extracted and then divided into 4 groups: G1 - absence of storage medium; G2 - milk u s e d as storage medium; G3 - milk used as storage medium a n d followed by GaAlAs laser irradiation on dental surfaces and at the entrance of alveolus; G4 - milk used as storage medium associated with laser irradiation as in G3 before and after replantation on the buccal and palatal mucosa every 48 hours for 15 days. The animals were sacrificed at 15, 30 and 60 days after replantation. The results showed that after 15 days G4 exhibit more intense chronic inflammation, with presence of clastic cells and moderate inflammatory root resorption (p<0.05) when compared to G3, which presented absence of those parameters. At day 30 in G1, G2 and G4 mild to moderate chronic inflammation and severe external root resorption were observed. G3 remained with no inflammation and inflammatory root resorption with 30 and 60 days of healing experimental times. The results suggest that laser irradiation on the dental entrance of the dental alveolus prior to tooth replantation has a positive biomodulative effect on the healing process in rats.

Influence of low-level laser on bone remodeling during induced tooth movement in rats.

PubMed

Cossetin, Eliziane; Janson, Guilherme; de Carvalho, Maria Goretti F; de Carvalho, Rejane A; Henriques, José Fernando Castanha; Garib, Daniela

2013-11-01

To analyze the effect of low-level laser on bone remodeling during induced tooth movement in rats. A diode laser (808 nm, 100 mW, 54 J on an area of 0.0028 cm(2)) was used. The application was continuous, punctual, and with contact. Forty-two 70-day-old Wistar rats had the maxillary left first molar moved using a force level of 25 g. In two experimental subgroups the movement was performed over 7 days and in three subgroups the movement occurred over 14 days. In the 7-day movement subgroups, one subgroup received laser irradiation on day 1 only; the other subgroup received laser irradiation on days 1, 3, and 5. In the 14-day movement subgroups, one subgroup received laser irradiation on day 1 only; the second on days 1, 3, and 5; and the third on days 1, 3, 5, 7, 9, 11, and 13. The control group was also divided into two subgroups, and movement occurred over two different periods of treatment (7 days and 14 days) without laser application; these were used as controls for the respective experimental subgroups. Inter-subgroup comparison was performed with Kruskal-Wallis, followed by Mann-Whitney and analysis of variance, followed by Tukey tests within the 7- and 14-day subgroups. The subgroup with three laser applications showed significantly greater osteoclastic activity and bone resorption than the other subgroups in the 7-day movement subgroups. Low-level laser application significantly increased the osteoclastic but not the osteoblastic activity during the initial phases of tooth movement. In addition, the osteoclastic activity was dose-dependent.

Cerebral morphology and functional sparing after prenatal frontal cortex lesions in rats.

PubMed

Kolb, B; Cioe, J; Muirhead, D

1998-03-01

Rats were given suction lesions of the presumptive frontal cortex on embryonic day 18 (E18) and subsequently tested, as adults, on tests of spatial navigation (Morris water task, radial arm maze), motor tasks (Whishaw reaching task, beam walking), and locomotor activity. Frontal cortical lesions at E18 affected cerebral morphogenesis, producing unusual morphological structures including abnormal patches of neurons in the cortex and white matter as well as neuronal bridges between the hemispheres. A small sample of E18 operates also had hydrocephaly. The animals with E18 lesions without hydrocephalus were behaviorally indistinguishable from littermate controls. The results demonstrate that animals with focal lesions of the presumptive frontal cortex have gross abnormalities in cerebral morphology but the lesions leave the functions normally subserved by the frontal cortex in adult rats unaffected. The results are discussed in the context of a hypothesis regarding the optimal times for functional recovery from cortical injury.

Doxycycline reduces the expression and activity of matrix metalloproteinase-2 in the periodontal ligament of the rat incisor without altering the eruption process.

PubMed

Gomes, J R; Omar, N F; Neves, J D S; Novaes, P D

2017-06-01

Doxycycline is an antibiotic agent that inhibits the activity of matrix metalloproteinases (MMPs) present in the extracellular matrix. In this study, the rat incisor was submitted to a hypofunctional condition, and the effects of doxycycline (80 mg/kg/d) on the expression and activity of MMP-2, as well as on eruption rate, were determined in the odontogenic region and in the periodontal ligament for 14 d. Rats were distributed into four groups: normofunctional (NF); doxycyline normofunctional (DNF); hypofunctional (HP); and doxycyline hypofunctional (DHP). The left lower incisors of 10 rats were shortened every 2 d, using a high-rotation drill, to produce the HP and DHP groups, after starting doxycycline treatment (80 mg/kg) by gavage. Eruption was measured using a millimeter ocular, from the gingival margin to the top of the tooth in the HP and DHP groups, and also by a mark made in the tooth previously, in the NF and DNF groups. The hemimandibles were removed and the teeth were extracted to collect the periodontal and odontogenic tissues for immunohistochemical analyses and zymography. The eruption rates were higher in the HP and the DHP groups than in the NF and DNF groups, respectively (p < 0.05). In the odontogenic region, neither of the treatments changed the expression and activity of MMP-2. In the HP group, the shortening treatment decreased the expression, but not the activity, of MMP-2, while doxycycline was able to inhibit the increase of expression and activity of MMP-2. We conclude that the inhibition of MMP-2 by doxycycline, during incisor shortening, was not enough to alter the eruption rate, which suggests that MMP-2 may have an important role in the turnover of extracellular matrix of the periodontal ligament during the tooth-eruption process. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Carbon nanotubes functionalized with sodium hyaluronate restore bone repair in diabetic rat sockets.

PubMed

Sá, M A; Andrade, V B; Mendes, R M; Caliari, M V; Ladeira, L O; Silva, E E; Silva, G A B; Corrêa-Júnior, J D; Ferreira, A J

2013-07-01

We evaluated the effects of sodium hyaluronate (HY) and carbon nanotubes functionalized with HY (HY-CNT) on bone repair in the tooth sockets of diabetic rats. Diabetes was induced by streptozotocin (50 mg kg(-1) i.v.), and the sockets were divided into normal control, diabetic control, diabetic treated with HY (1%), and diabetic treated with HY-CNT (100 μg ml(-1)) groups. The sockets were analyzed according to the percentage of bone formation and the number of cell nuclei. The percentage of bone trabeculae was lower in diabetic control animals (11.16 ± 5.10% vs 41.92 ± 6.34% in normal animals) after 14 days. Treating diabetic animals with HY or HY-CNT significantly increased the percentage of neoformed trabeculae (HY: 29.43 ± 3.29%; HY-CNT: 36.90 ± 3.07%). Moreover, the sockets of diabetic animals had an increased number of cell nuclei and HY or HY-CNT reduced this parameter. Our results indicate that HY and HY-CNT restore bone repair in the tooth sockets of diabetic rats, suggesting that these biomaterials are potential adjuvant therapies for the management of diabetes. © 2012 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

[Sclerostin expression in periodontal ligaments during movement of orthodontic teeth in rats].

PubMed

Yiwen, Chen; Shang, Gao; Tongtong, Xu; Jiahui, Zhang; Jincheng, Li; Huiyan, Zhang; Jinjin, Lu; Min, Hu; Zhihui, Liu

2016-06-01

This study aims to observe the expression of Sclerostin during movement of orthodontic teeth and determine the effect of this protein on remodeling of periodontal tissues. Twenty-four Wistar rats were chosen. Orthodontic forces were applied between the bilateral incisor and first molar to achieve mesial movement. Rats in each group were executed at different time points (0, 1, 3, 5, 7, 14 d). Morphology of periodontal tissue was observed by hematoxylin-eosin (HE) staining. The number of osteoclasts were observed by tartrate-resistant acid phosphatase (TRAP) staining. Sclerostin expression were observed by immunohistochemical staining. HE staining revealed that the resorption of alveolar bone intensified with prolonged movement. Results of immunohistochemical and TRAP staining revealed that Sclerostin expression and number of osteoclasts were related to duration of movement of orthodontic tooth. After staining for 5 days, the number of osteoclasts and Sclerostin expression reached their peak and then began to decline. The numbers of osteoclasts and the expression level of Sclerostin were higher at the compressive side than those at the tensive side. Sclerostin affected orthodontic tooth movement by inhibiting the Wnt signaling pathway and by indirectly or directly controlling bone morphogenetic protein.

Effects of pulsed electromagnetic field vibration on tooth movement induced by magnetic and mechanical forces: a preliminary study.

PubMed

Darendeliler, M Ali; Zea, A; Shen, G; Zoellner, H

2007-12-01

This study was designed to determine whether or not high-frequency and low-magnitude vibration affects orthodontic tooth movement caused by magnetic or/and mechanical forces. Forty-four 7-week-old Wistar rats were randomly divided into four groups, with each group further divided into experimental and control subgroups. Neodymium-Iron-Boron (Nd-Fe-B) magnets and Sentalloy closed coil springs were placed between maxillary or mandibular first molars and incisors to activate tooth movement. The animals of experimental subgroups were exposed to the vibration induced by pulsed electromagnetic fields (PEMF) whilst the control subgroups were under normal atmosphere. The experiment lasted for 14 days and all of the animals were sacrificed for examination. The changes in the space between the molar and incisor were measured to indicate the amount of tooth movement. The coil springs, either with sham or active magnets, move molar much more than magnets alone, regardless of absence or presence of PEMF (p < 0.001). Under PEMF, the coil spring moved significantly more amount of tooth movement than that of coil-magnet combination (p < 0.01), as did the magnets compared to sham magnets (p < 0.019). Under a non-PEMF scenario, there was no significant difference in tooth movement between coil spring and coil-magnets combination, nor was there difference between magnets and sham magnets. It is suggested that the PEMF-induced vibration may enhance the effect of mechanical and magnetic forces on tooth movement.

Effects of clodronate on early alveolar bone remodeling and root resorption related to orthodontic forces: a histomorphometric analysis.

PubMed

Choi, Josefina; Baek, Seung-Hak; Lee, Jae-Il; Chang, Young-Il

2010-11-01

The objective of this study was to evaluate the short-term effects of clodronate, a first-generation bisphosphonate, on early alveolar bone remodeling and root resorption related to orthodontic tooth movement. The samples consisted of 54 sex-matched Wistar rats (weight, 180-230 g) allocated to the 2.5 mmol/L clodronate, 10 mmol/L clodronate, and control groups (n = 18 for each group). After application of a nickel-titanium closed-coil spring (force, 60 g) between the maxillary central incisor and first molar, 2.5 mmol/L of clodronate, 10 mmol/L of clodronate, or saline solution was injected into the subperiosteum adjacent to the maxillary first molar every third day. All animals received tetracycline, calcein, and alizarin red by intraperitoneal injection at 1, 6, and 14 days, respectively. The amounts of tooth movement were measured at 3, 6, 9, 12, and 15 days. The animals were killed at 4, 7, and 17 days. Histomorphometric analyses of bone mineral appositional rate, labeled surface, percentage of root resorption area, and number of root resorption lacunae of the mesiobuccal root of the maxillary first molar at 4, 7, and 17 days were done. One-way analysis of variance (ANOVA) with the post-hoc test were done for statistical analyses. Rats in the 10 mmol/L clodronate group had significant decreases of tooth movement (12 and 15 days, P <0.05) and percentages of root resorption area and numbers of root resorption lacunae (7 day, P <0.05), and increases of labeled surface and mineral appositional rates (17 day, P <0.05) over those of the 2.5 mmol/L clodronate and control groups. Although clodronate might decrease root resorption related to orthodontic tooth movement, patients should be informed about a possible decrease in the amount of tooth movement and a prolonged period of orthodontic treatment. Copyright © 2010 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Mosaic Convergence of Rodent Dentitions

PubMed Central

Lazzari, Vincent; Charles, Cyril; Tafforeau, Paul; Vianey-Liaud, Monique; Aguilar, Jean-Pierre; Jaeger, Jean-Jacques; Michaux, Jacques; Viriot, Laurent

2008-01-01

Background Understanding mechanisms responsible for changes in tooth morphology in the course of evolution is an area of investigation common to both paleontology and developmental biology. Detailed analyses of molar tooth crown shape have shown frequent homoplasia in mammalian evolution, which requires accurate investigation of the evolutionary pathways provided by the fossil record. The necessity of preservation of an effective occlusion has been hypothesized to functionally constrain crown morphological changes and to also facilitate convergent evolution. The Muroidea superfamily constitutes a relevant model for the study of molar crown diversification because it encompasses one third of the extant mammalian biodiversity. Methodology/Principal Findings Combined microwear and 3D-topographic analyses performed on fossil and extant muroid molars allow for a first quantification of the relationships between changes in crown morphology and functionality of occlusion. Based on an abundant fossil record and on a well resolved phylogeny, our results show that the most derived functional condition associates longitudinal chewing and non interlocking of cusps. This condition has been reached at least 7 times within muroids via two main types of evolutionary pathways each respecting functional continuity. In the first type, the flattening of tooth crown which induces the removal of cusp interlocking occurs before the rotation of the chewing movement. In the second type however, flattening is subsequent to rotation of the chewing movement which can be associated with certain changes in cusp morphology. Conclusion/Significance The reverse orders of the changes involved in these different pathways reveal a mosaic evolution of mammalian dentition in which direction of chewing and crown shape seem to be partly decoupled. Either can change in respect to strong functional constraints affecting occlusion which thereby limit the number of the possible pathways. Because convergent pathways imply distinct ontogenetic trajectories, new Evo/Devo comparative studies on cusp morphogenesis are necessary. PMID:18974837

Histologic evaluation of the effect of mineral trioxide aggregate-Fillapex as a root canal sealer in rat teeth submitted to late replantation

PubMed Central

Ferreira, Manuel Marques; Botelho, Maria Filomena; Abrantes, Margarida; Carvalho, Lina; Carrilho, Eunice

2017-01-01

Objective: This study aims to analyze the effect of new root canal based silicate cement, in rat teeth after late replantation, comparing with calcium hydroxide (CH) in preventing tooth root resorption. Materials and Methods: The study group included 16 Wistar rats in which the upper right central incisors were extracted and were left on a worktable for 60 min, simulating a case of tooth avulsion, after had been anesthetized. One group, (Group I), the canals were filled with CH past, before replantation. The second groups of teeth, (Group II), the canals were filled with mineral trioxide aggregate-Fillapex (MTAF). After removal, the blood clot of the socket, with saline solution irrigation, the teeth were replanted into their original socket, and splinted with silk 3/0. The rats were sacrificed 8 weeks after replantation and the specimens were prepared for histologic and histomorphometric analyses. The areas of inflammatory and replacement resorptions were selected and quantified. These data for each group of teeth were evaluated and analyzed using the Mann–Whitney test (P = 0.05). Result and Conclusion: All the replanted teeth in both groups survived. Although root canal filled with MTAF provide better results than with CH past concerning inflammatory and replacement resorption, there was no statistical difference (P = 0.527). PMID:28435372

Age-related effects on osteoclastic activities after orthodontic tooth movement.

PubMed

Li, X; Li, M; Lu, J; Hu, Y; Cui, L; Zhang, D; Yang, Y

2016-10-01

To elucidate the effects of age on the expression levels of the receptor activator of the nuclear factor-κB ligand (RANKL) and osteoclasts in the periodontal ligament during orthodontic mechanical loading and post-orthodontic retention. The study included 20 male Sprague-Dawley rats, ten in the young group (aged four to five weeks) and ten in the adult group (aged 18 to 20 weeks). In each rat, the upper-left first molar was subjected to a seven-day orthodontic force loading followed by a seven-day retention period. The upper-right first molar served as a control. The amount of orthodontic tooth movement was measured after seven-day force application and seven-day post-orthodontic retention. The expression levels of RANKL and the tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts were evaluated on day 7 (end of mechanical force loading) and day 14 (after seven days of post-orthodontic retention). Statistical analysis was performed using the t-test, and significance was set at p < 0.05. There was no significant difference between the amount of tooth movement in the young group (0.96, standard deviation (sd) 0.30mm) and that in the adult group (0.80mm, sd 0.28) (p > 0.05) after the seven-day force application. On the compression side, the expression of RANKL and TRAP-positive osteoclasts in both the young and the adult groups increased after the application of force for seven days, and then decreased at the end of the seven-day retention period. However, by the end of the period, the expression of RANKL on the compression side dropped to the control level in the young group (p > 0.05), while it was still higher than that on the control side in the adult group (p < 0.05). The expression of RANKL on the compression side did not show significant difference between the young and the adult groups after seven-day force application (p > 0.05), but it was significantly higher in the adult group than that in the young group after seven-day post-orthodontic retention (p < 0.05). Similarly, the decreasing trend of TRAP-positive osteoclasts during the retention period in the adult group was less obvious than that in the young group. The bone-resorptive activity in the young rats was more dynamic than that in the adult rats. The expression of RANKL and the number of osteoclasts in adult rats did not drop to the control level during the post-orthodontic retention period while RANKL expression and the number of osteoclasts in young rats had returned to the baseline.Cite this article: X. Li, M. Li, J. Lu, Y. Hu, L. Cui, D. Zhang, Y. Yang. Age-related effects on osteoclastic activities after orthodontic tooth movement. Bone Joint Res 2016;5:492-499. DOI: 10.1302/2046-3758.510.BJR-2016-0004.R2. © 2016 Li et al.

Expression of Mineralized Tissue Associated Proteins: Dentin Sialoprotein and Phosphophoryn in Rodent Hair Follicles

PubMed Central

Tang, Xu-na; Zhu, Ya-qin; Marcelo, Cynthia L.; Ritchie, Helena H.

2012-01-01

Background Mammalian hair development and tooth development are controlled by a series of reciprocal epithelial-mesenchymal interactions. Similar growth factors and transcription factors, such as fibroblast growth factor (FGF), sonic hedgehog homolog (SHH), bone morphogenetic proteins (BMPs) and Wnt10a, were reported to be involved in both of these interactions. Dentin sialoprotein (DSP) and phosphophoryn (PP) are the two major non-collagenous proteins secreted by odontoblasts that participate in dentin mineralization during tooth development. Because of striking similarities between tooth development and hair follicle development, we investigated whether DSP and/or PP proteins may also play a role in hair follicle development. Objective In this study, we examined the presence and location of DSP/PP proteins during hair follicle development. Methods Rat PP proteins were detected using immunohistochemical/immunofluorescent staining. DSP-PP mRNAs were detected by in situ hybridization with riboprobes. LacZ expression was detected in mouse tissues using a DSP-PP promoter-driven LUC in transgenic mice. Results We found that PP proteins and DSP-PP mRNAs are present in rat hair follicles. We also demonstrate that an 8 kb DSP-PP promoter is able to drive lacZ expression in hair follicles. Conclusion We have firmly established the presence of DSP/PP in mouse and rat hair follicles by immunohistochemical/immunofluorescent staining, in situ hybridization with riboprobes and transgenic mice studies. The expression of DSP/PP in hair follicles is the first demonstration that major mineralization proteins likely may also contribute to soft tissue development. This finding opens a new avenue for future investigations into the molecular-genetic management of soft tissue development. PMID:21908176

Expression of mineralized tissue associated proteins: dentin sialoprotein and phosphophoryn in rodent hair follicles.

PubMed

Tang, Xu-na; Zhu, Ya-qin; Marcelo, Cynthia L; Ritchie, Helena H

2011-11-01

Mammalian hair development and tooth development are controlled by a series of reciprocal epithelial-mesenchymal interactions. Similar growth factors and transcription factors, such as fibroblast growth factor (FGF), sonic hedgehog homolog (SHH), bone morphogenetic proteins (BMPs) and Wnt10a, were reported to be involved in both of these interactions. Dentin sialoprotein (DSP) and phosphophoryn (PP) are the two major non-collagenous proteins secreted by odontoblasts that participate in dentin mineralization during tooth development. Because of striking similarities between tooth development and hair follicle development, we investigated whether DSP and/or PP proteins may also play a role in hair follicle development. In this study, we examined the presence and location of DSP/PP proteins during hair follicle development. Rat PP proteins were detected using immunohistochemical/immunofluorescent staining. DSP-PP mRNAs were detected by in situ hybridization with riboprobes. LacZ expression was detected in mouse tissues using a DSP-PP promoter-driven LUC in transgenic mice. We found that PP proteins and DSP-PP mRNAs are present in rat hair follicles. We also demonstrate that an 8 kb DSP-PP promoter is able to drive lacZ expression in hair follicles. We have firmly established the presence of DSP/PP in mouse and rat hair follicles by immunohistochemical/immunofluorescent staining, in situ hybridization with riboprobes and transgenic mice studies. The expression of DSP/PP in hair follicles is the first demonstration that major mineralization proteins likely may also contribute to soft tissue development. This finding opens a new avenue for future investigations into the molecular-genetic management of soft tissue development. Copyright © 2011 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

Radiological and histopathological evaluation of experimentally-induced periapical lesion in rats

PubMed Central

TEIXEIRA, Renata Cordeiro; RUBIRA, Cassia Maria Fischer; ASSIS, Gerson Francisco; LAURIS, José Roberto Pereira; CESTARI, Tania Mary; RUBIRA-BULLEN, Izabel Regina Fischer

2011-01-01

Objective This study evaluated experimentally-induced periapical bone loss sites using digital radiographic and histopathologic parameters. Material and Methods Twenty-seven Wistar rats were submitted to coronal opening of their mandibular right first molars. They were radiographed at 2, 15 and 30 days after the operative procedure by two digital radiographic storage phosphor plates (Digora®). The images were analyzed by creating a region of interest at the periapical region of each tooth (ImageJ) and registering the corresponding pixel values. After the sacrifice, the specimens were submitted to microscopic analysis in order to confirm the pulpal and periapical status of the tooth. Results There was significant statistically difference between the control and test sides in all the experimental periods regarding the pixel values (two-way ANOVA; p<0.05). Conclusions The microscopic analysis proved that a periapical disease development occurred during the experimental periods with an evolution from pulpal necrosis to periapical bone resorption. PMID:21922123

A novel whole tooth-in-jaw-bone culture of rat molars: morphological, immunohistochemical, and laser capture microdissection analysis.

PubMed

Chokechanachaisakul, Uraiwan; Kaneko, Tomoatsu; Yamanaka, Yusuke; Okiji, Takashi; Suda, Hideaki

2012-10-01

In conventional whole-tooth culture systems, limitation exists regarding maintenance of the vitality of the dental pulp, because this tissue is encased in rigid dentin walls that hinder nutrition supply. We here report a whole tooth-in-jaw-bone culture system of rat mandibular first molars, where transcardiac perfusion with culture medium was carried out before placement of the jaw bone into culture medium, aiming to facilitate longer time preservation of the dental pulp tissue. Following 7 days of culture, the pulp tissues were analyzed by histology and immunohistochemistry to ED2 (antiresident macrophage). ED2-positive macrophages were also analyzed for their Class II MHC, interleukin-6 (IL-6), and p53 mRNA expression levels by means of immune-laser capture microdissection (immune-LCM). Dentin sialophosphoprotein (DSPP) mRNA expression in odontobalstic layer was also examined by LCM. Teeth cultured following saline-perfusion and nonperfusion served as cultured controls. Normal teeth also served as noncultured controls. Histological examination demonstrated that the structure of the pulp tissue was well preserved in the medium-perfused explants in contrast to the cultured control groups. The Class II MHC, IL-6, and p53 mRNA expression levels of ED2-positive cells and DSPP expression levels of odontoblastic layer tissues in the pulp of medium-perfused explants were not significantly different from those in the noncultured normal teeth. In conclusion, the structural integrity and mRNA expression in the pulp were maintained at the in vivo level in the ex vivo whole tooth-in-jaw-bone culture system. The system may lay the foundation for studies aiming at defining further histological and molecular mechanism of the pulp. Copyright © 2012 Wiley Periodicals, Inc.

Effects of pulpectomy on the amount of root resorption during orthodontic tooth movement.

PubMed

Kaku, Masato; Sumi, Hiromi; Shikata, Hanaka; Kojima, Shunichi; Motokawa, Masahide; Fujita, Tadashi; Tanimoto, Kotaro; Tanne, Kazuo

2014-03-01

Previous studies have revealed that orthodontic force affects dental pulp via the rupture of blood vessels and vacuolization of pulp tissues. We hypothesized that pulp tissues express inflammatory cytokines and regulators of odontoclast differentiation after excess orthodontic force. The purpose of this study was to investigate the effects of tensile force in human pulp cells and to measure inflammatory root resorption during tooth movement in pulpless rat teeth. After cyclic tensile force application in human pulp cells, gene expression and protein concentration of macrophage colony-stimulating factor, receptor activator of nuclear factor kappa-B ligand, interleukin-1 beta, and tumor necrosis factor alpha were determined by real-time polymerase chain reaction and enzyme-linked immunoassay. Moreover, the role of the stretch-activated channel was evaluated by gadolinium (Gd(3+)) treatment. The upper right first molars of 7-week Wistar rats were subjected to pulpectomy and root canal filling followed by mesial movement for 6 months. The expression of cytokine messenger RNAs and proteins in the experimental group peaked with loading at 10-kPa tensile force after 48 hours (P < .01). Gd(3+) reduced the expression of these cytokine messenger RNAs and protein concentrations (P < .01). The amount of inflammatory root resorption was significantly larger in the control teeth than the pulpectomized teeth (P < .05). This study shows that tensile forces in the pulp cells enhance the expression of various cytokines via the S-A channel, which may lead to inflammatory root resorption during tooth movement. It also suggests that root canal treatment is effective for progressive severe inflammatory root resorption during tooth movement. Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Distinctive Tooth-Extraction Socket Healing: Bisphosphonate Versus Parathyroid Hormone Therapy

PubMed Central

Kuroshima, Shinichiro; Mecano, Rodan B.; Tanoue, Ryuichiro; Koi, Kiyono; Yamashita, Junro

2014-01-01

Background Patients with osteoporosis who receive tooth extractions are typically on either oral bisphosphonate or parathyroid hormone (PTH) therapy. Currently, the consequence of these therapies on hard- and soft-tissue healing in the oral cavity is not clearly defined. The aim of this study is to determine the differences in the therapeutic effect on tooth-extraction wound healing between bisphosphonate and PTH therapies. Methods Maxillary second molars were extracted in Sprague Dawley rats (n = 30), and either bisphosphonate (zoledronate [Zol]), PTH, or saline (vehicle control [VC]) was administered for 10 days (n = 10 per group). Hard-tissue healing was evaluated by microcomputed tomography and histomorphometric analyses. Collagen, blood vessels, inflammatory cell infiltration, and cathepsin K expression were assessed in soft tissue using immunohistochemistry, quantitative polymerase chain reaction, and immunoblotting. Results Both therapies significantly increased bone fill and suppressed vertical bone loss. However, considerably more devital bone was observed in the sockets of rats on Zol versus VC. Although Zol increased the numbers of blood vessels, the total blood vessel area in soft tissue was significantly smaller than in VC. PTH therapy increased osteoblastic bone formation and suppressed osteoclasts. PTH therapy promoted soft-tissue maturation by suppressing inflammation and stimulating collagen deposition. Conclusion Zoledronate therapy deters whereas PTH therapy promotes hard- and soft-tissue healing in the oral cavity, and both therapies prevent vertical bone loss. PMID:23688101

Cementocyte cell death occurs in rat cellular cementum during orthodontic tooth movement.

PubMed

Matsuzawa, Humihiro; Toriya, Naoko; Nakao, Yuya; Konno-Nagasaka, Moe; Arakawa, Toshiya; Okayama, Miki; Mizoguchi, Itaru

2017-05-01

To clarify the mechanism of root resorption during orthodontic treatment, we examined cementocyte cell death and root resorption in the cellular cementum on the pressure side during experimental tooth movement. Using 8-week-old male Wistar rats, the right first molar was pushed mesiobuccally with a force of 40 g by a Ni-Ti alloy wire while the contralateral first molar was used as a control. Localization and number of cleaved caspase-3-positive and single-stranded DNA (ssDNA) - positive cells were evaluated using dual-label immunohistochemistry with anticleaved caspase-3 and anti-ssDNA antibodies. In addition, tartrate-resistant acid phosphatase (TRAP)-positive cells in the cellular cementum were evaluated using TRAP histochemical staining. Caspase-3- and ssDNA-positive cells appeared at 12 hours, but were restricted to the compressed periodontal ligament (PDL) and not the cellular cementum. Cleaved caspase-3-positive cementocytes were observed in the cellular cementum adjacent to the compressed PDL on day 1. From days 2 to 4, the number of caspase-3- and ssDNA-positive cementocytes increased. TRAP-positive cells appeared on the cellular cementum at the periphery of the hyalinized tissue on day 7, and resorption progressed into the broad surface of the cementum by day 14. Cementocytes adjacent to the hyalinized tissue underwent apoptotic cell death during orthodontic tooth movement, which might have been associated with subsequent root resorption.

Chronology and regulation of gene expression of RANKL in the rat dental follicle.

PubMed

Liu, D; Yao, S; Pan, F; Wise, G E

2005-10-01

Tooth eruption in the rat requires bone resorption resulting from a major burst of osteoclastogenesis on postnatal day 3 and a minor burst of osteoclastogenesis on postnatal day 10 in the alveolar bone of the first mandibular molar. The dental follicle regulates the major burst on postnatal day 3 by down-regulating its osteoprotegerin (OPG) gene expression to enable osteoclastogenesis to occur. To determine the role of receptor activator of nuclear factor-kappa B ligand (RANKL) in tooth eruption, its gene expression was measured on postnatal days 1-11 in the dental follicle. The results show that RANKL expression was significantly elevated on postnatal days 9-11 in comparison to low expression levels at earlier time-points. As OPG expression is high at this latter time-point, this increase in RANKL expression would be needed for stimulating the minor burst of osteoclastogenesis. Tumor necrosis factor-alpha enhances RANKL gene expression in vitro and it may be responsible for up-regulating RANKL in vivo. Transforming growth factor-beta1 and interleukin-1alpha also enhance RANKL gene expression in vitro but probably have no effect in vivo because they are maximally expressed early. Bone morphogenetic protein-2 acts to down-regulate RANKL expression in vitro and, in vivo, may promote alveolar bone growth in the basal region of the tooth.

A fine-structural survey of the pulpal innervation in the rat mandibular incisor.

PubMed

Bishop, M A

1981-02-01

The innervation of the rat incisor pulp has been studied using transmission electron microscopy and light microscopy. Transverse sections of mandibular incisor pulp (380-460 gm rats) from numerous positions in the long axis of the tooth were examined systematically in the electron microscopy. Quantitative data on total axon populations were obtained. The nerve fibers were found to pass through the lingual half of the pulp from the apical end to within 2 mm of the incisal tip. Although the nerve fibers were seen to lie amongst the connective tissue cells between the blood vessels, the electron microscopic observations showed that the blood vessels are not innervated. Throughout their pulpal course the nerve fibers showed no trace of perineurial investment. Virtually all the axons were unmyelinated. Total numbers of axons were small (233-328) and peak diameters of 0.3-0.4 microM confirmed the observed immature appearance of the nerve supply. Obvious nerve endings were seldom observed and the axons showed no structural association with odontoblasts. The evidence indicates that, although most axons terminate near the incisal end of the tooth, no specific structure is supplied. The qualitative features of the axons do not suggest autonomic function; however, they are consistent with a sensory role.

Up-regulation of Wnt5a gene expression in the nitrofen-induced hypoplastic lung.

PubMed

Doi, Takashi; Puri, Prem

2009-12-01

The pathogenesis of pulmonary hypoplasia in nitrofen-induced congenital diaphragmatic hernia (CDH) still remains unclear. Wnt signaling pathways play a critical role in lung development. Whereas canonical Wnt signaling regulates branching morphogenesis during early lung development, the noncanonical Wnt5a controls late lung morphogenesis, including patterning of distal airway and vascular tubulogenesis (alveolarization). Overexpression of Wnt5a in transgenic mice and in the chick has been reported to result in severe pulmonary hypoplasia. We designed this study to test the hypothesis that the pulmonary Wnt5a gene expression is up-regulated in late stages of lung morphogenesis in CDH. Pregnant rats were exposed to either olive oil or nitrofen on day 9 of gestation (D9). Fetal lungs were harvested on D15, D18, and D21 and divided into 3 groups: control; nitrofen without CDH, CDH(-); and nitrofen with CDH, CDH(+) (n = 8 at each time-point, respectively). Wnt5a pulmonary gene expression was analyzed by real-time reverse transcription polymerase chain reaction. Immunohistochemistry was performed to evaluate Wnt5a protein expression at each time-point. Pulmonary relative mRNA expression levels of Wnt5a were significantly increased in CDH(-) and CDH(+) at D18 (1.61 +/- 0.92 and 1.81 +/- 1.20, respectively) and D21 (2.40 +/- 0.74* and 2.65 +/- 0.35*, respectively) compared to controls at D18 and D21 (0.90 +/- 0.17* and 1.69 +/- 0.53**, respectively) (*P < .05, **P < .001 vs control ). Strong Wnt5a immunoreactivity was seen in the distal epithelium at D18 and D21 in nitrofen-induced hypoplastic lung compared to controls. Up-regulation of pulmonary Wnt5a gene expression in the late lung morphogenesis may interfere with patterning of alveolarization, causing pulmonary hypoplasia in the nitrofen-induced CDH.

A simple and efficient method for generating Nurr1-positive neuronal stem cells from human wisdom teeth (tNSC) and the potential of tNSC for stroke therapy.

PubMed

Yang, Kuo-Liang; Chen, Mei-Fang; Liao, Chia-Hsin; Pang, Cheng-Yoong; Lin, Py-Yu

2009-01-01

We have isolated human neuronal stem cells from exfoliated third molars (wisdom teeth) using a simple and efficient method. The cultured neuronal stem cells (designated tNSC) expressed embryonic and adult stem cell markers, markers for chemotatic factor and its corresponding ligand, as well as neuron proteins. The tNSC expressed genes of Nurr1, NF-M and nestin. They were used to treat middle cerebral artery occlusion (MCAO) surgery-inflicted Sprague-Dawley (SD) rats to assess their therapeutic potential for stroke therapy. For each tNSC cell line, a normal human impacted wisdom tooth was collected from a donor with consent. The tooth was cleaned thoroughly with normal saline. The molar was vigorously shaken or vortexed for 30 min in a 50-mL conical tube with 15-20mL normal saline. The mixture of dental pulp was collected by centrifugation and cultured in a 25-cm(2) tissue culture flask with 4-5mL Medium 199 supplemented with 5-10% fetal calf serum. The tNSC harvested from tissue culture, at a concentration of 1-2x10(5), were suspended in 3 microL saline solution and injected into the right dorsolateral striatum of experimental animals inflicted with MCAO. Behavioral measurements of the tNSC-treated SD rats showed a significant recovery from neurologic dysfunction after MCAO treatment. In contrast, a sham group of SD rats failed to recover from the surgery. Immunohistochemistry analysis of brain sections of the tNSC-treated SD rats showed survival of the transplanted cells. These results suggest that adult neuronal stem cells may be procured from third molars, and tNSC thus cultivated have potential for treatment of stroke-inflicted rats.

Evaluation of antibacterial and remineralizing nanocomposite and adhesive in rat tooth cavity model

PubMed Central

Li, Fang; Wang, Ping; Weir, Michael D.; Fouad, Ashraf F.; Xu, Hockin H. K.

2014-01-01

Antibacterial and remineralizing dental composites and adhesives were recently developed to inhibit biofilm acids and combat secondary caries. It is not clear what effect these materials will have on dental pulps in vivo. The objectives of this study were to investigate the antibacterial and remineralizing restorations in a rat tooth cavity model, and determine pulpal inflammatory response and tertiary dentin formation. Nanoparticles of amorphous calcium phosphate (NACP) and antibacterial dimethylaminododecyl methacrylate (DMADDM) were synthesized and incorporated into a composite and an adhesive. Occlusal cavities were prepared in the first molars of rats and restored with four types of restoration: Control composite and adhesive; control plus DMADDM; control plus NACP; and control plus both DMADDM and NACP. At 8 or 30 days (d), rat molars were harvested for histological analysis. For inflammatory cell response, regardless of time periods, NACP group and DMADDM+NACP group showed lower scores (better biocompatibility) than control group (p = 0.014 for 8 d, p = 0.018 for 30 d). For tissue disorganization, NACP and DMADDM+NACP had better scores than control (p = 0.027) at 30 d. At 8 d, restorations containing NACP had tertiary dentin thickness (TDT) that was 5-6 fold that of control. At 30 d, restorations containing NACP had TDT that was 4-6 fold that of control. In conclusion, novel antibacterial and remineralizing restorations were tested in rat teeth in vivo for the first time. Composite and adhesive containing NACP and DMADDM exhibited milder pulpal inflammation and much greater tertiary dentin formation, than control adhesive and composite. Therefore, the novel composite and adhesive containing NACP and DMADDM are promising as a new therapeutic restorative system to not only combat oral pathogens and biofilm acids as shown previously, but also facilitate the healing of the dentin-pulp complex. PMID:24583320

Bisphosphonates inhibit bone remodeling in the jaw bones of rats and delay healing following tooth extractions.

PubMed

Jabbour, Zaher; El-Hakim, Michel; Henderson, Janet E; de Albuquerque, Rubens F

2014-05-01

This study aimed to evaluate the impact of concurrent administration of clinically relevant doses of zoledronic acid (ZA) and dexamethasone (DX) on bone healing after tooth extraction (EXO). Forty-four Sprague-Dawley rats (6-8 month old) were randomized into five groups: ZA + DX = weekly injection of ZA with DX for 7 weeks; WD = ZA with DX for 3 weeks then DX alone for 4 weeks; C = control saline for 7 weeks; ZA = ZA alone for 7 weeks and DX = DX alone for 7 weeks. ZA was administered at 0.13 mg/kg/week and DX at 3.8 mg/kg/week and body weights recorded at the time of injection. All rats underwent extraction (EXO) of the mandibular and maxillary first molars at 3 weeks and were euthanized at 7 weeks. The extracted and non-extracted sides of both jaws were harvested for micro-CT analyses. All rats, particularly those injected with ZA, exhibited weight gain till EXO followed by decline then recovery. ZA + DX group demonstrated highest fractional bone to tissue volume (BV/TV) in the non-extracted side. ZA + DX rats exhibited also highest volume and surface of sequestra. Only sequestra volume was statistically higher in the WD group compared to C group. Combined treatment with ZA and DX over a prolonged period inhibits bone remodeling and increased sequestra formation to a greater extent than either drug alone. Trauma caused by these sequestra cutting through the mucosa could play a key role in the development of BRONJ by potentially facilitating infection. ZA withdrawal may promote bone-remodeling reactivation following EXO. Copyright © 2014 Elsevier Ltd. All rights reserved.

Establishment and localization of mixtures of Streptococcus mutans serotypes in the oral cavity of the rat.

PubMed

Huis in 't Veld, J H; Drost, J S; Havenaar, R

1982-10-01

The colonization of S. mutans serotypes on different tooth surfaces of the rat was investigated. Fissures appeared to be the main habitat. In the presence of a serotype c strain, S. mutans serotype d could only be established when sucrose-containing diets were supplied. However, the serotype c strain was always present in higher proportions. The production of a bacteriocin for which the serotype d strain was sensitive appeared to be responsible for the observed predominance of the serotype c strain.

Mites (acari) infesting commensal rats in Suez Canal zone, Egypt.

PubMed

el Kady, G A; Shoukry, A; Ragheb, D A; el Said, A M; Habib, K S; Morsy, T A

1995-08-01

Mites are arthropods distinguished from ticks by usually being microscopical in size and have a hypostome unarmed with tooth-like anchoring processes. They are group in a number of suborders, each with super-families and families including many genera of medical and economic importance. In this paper, commensal rodents (Rattus norvegicus, R. r. alexandrinus and R. r. frugivorous) were surveyed in the Suez Canal Zone for their acari ectoparasites. Four species of mites were recovered. In a descending order of mite indices, they were Eulaelaps stabularis (4.83 on 6 rats), Laelaps nuttalli (3.11 on 27 rats), Ornithonyssus bacoti (1.66 on 9 rats) and Dermanyssus gallinae (0.66 on 24 rats). The overall mite indices in the three governorates were 3.66 in Suez, 2.82 in Ismailia and zero in Port Said. The medical and economic importance of the mites were discussed.

The effect of anchovy substrate application to fluor retention rate on Sprague Dawley rat tooth email (in vivo)

NASA Astrophysics Data System (ADS)

Zabrina, S.; Puspitawati, R.; Gunawan, H. A.

2017-08-01

Usage of anchovies (Stolephorus insularis), which contain a high fluoride concentration in a CaF2 compound, needs to be examined as a topical fluoridative agent. Aim: To study the effects of an anchovy substrate application, either by chewing or smearing, in increasing fluoride retention of enamel. Fourteen Sprague Dawley rats were divided into five groups: baseline, experimental (feeding and smearing), and negative controls. After 15 days, lower incisor teeth were extracted and fluoride retention on the enamel surface was measured using EDX. Data were analyzed by the independent samples t-test, the Mann-Whitney U test, and the Kruskal-Wallis test. There was a significant increase in fluoride retention on enamel from the experimental groups compared to the negative control group (p < 0.05). Fluoride retention levels of the experimental feeding group (6.823%) were slightly higher than those of the experimental smearing group (6.783%), though the difference was not statistically significant (p < 0.05). Anchovy substrate application, either by chewing or smearing, increases fluoride retention on tooth enamel.

Positive Selection Linked with Generation of Novel Mammalian Dentition Patterns.

PubMed

Machado, João Paulo; Philip, Siby; Maldonado, Emanuel; O'Brien, Stephen J; Johnson, Warren E; Antunes, Agostinho

2016-09-11

A diverse group of genes are involved in the tooth development of mammals. Several studies, focused mainly on mice and rats, have provided a detailed depiction of the processes coordinating tooth formation and shape. Here we surveyed 236 tooth-associated genes in 39 mammalian genomes and tested for signatures of selection to assess patterns of molecular adaptation in genes regulating mammalian dentition. Of the 236 genes, 31 (∼13.1%) showed strong signatures of positive selection that may be responsible for the phenotypic diversity observed in mammalian dentition. Mammalian-specific tooth-associated genes had accelerated mutation rates compared with older genes found across all vertebrates. More recently evolved genes had fewer interactions (either genetic or physical), were associated with fewer Gene Ontology terms and had faster evolutionary rates compared with older genes. The introns of these positively selected genes also exhibited accelerated evolutionary rates, which may reflect additional adaptive pressure in the intronic regions that are associated with regulatory processes that influence tooth-gene networks. The positively selected genes were mainly involved in processes like mineralization and structural organization of tooth specific tissues such as enamel and dentin. Of the 236 analyzed genes, 12 mammalian-specific genes (younger genes) provided insights on diversification of mammalian teeth as they have higher evolutionary rates and exhibit different expression profiles compared with older genes. Our results suggest that the evolution and development of mammalian dentition occurred in part through positive selection acting on genes that previously had other functions. © The Author(s) 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Orthodontic buccal tooth movement by nickel-free titanium-based shape memory and superelastic alloy wire.

PubMed

Suzuki, Akihiro; Kanetaka, Hiroyasu; Shimizu, Yoshinaka; Tomizuka, Ryo; Hosoda, Hideki; Miyazaki, Shuichi; Okuno, Osamu; Igarashi, Kaoru; Mitani, Hideo

2006-11-01

To examine the mechanical properties and the usefulness of titanium-niobium-aluminum (Ti-Nb-Al) wire in orthodontic tooth movement as compared with nickel-titanium (Ni-Ti) wire. The load deflection of expansion springs was gauged with an original jig. The gradient of the superelastic region was measured during the unloading process. Expansion springs comprising the two types of alloy wires were applied to upper first molars of rats. The distance between the first molars was measured with micrometer calipers. The force magnitude of the Ti-Nb-Al expansion spring was lower than that of the Ni-Ti expansion spring over the entire deflection range. The initial force magnitude and the gradient in the superelastic region of the Ti-Nb-Al expansion springs were half those of the Ni-Ti expansion springs. Thus, Ti-Nb-Al expansion springs generated lighter and more continuous force. Tooth movement in the Ni-Ti group proceeded in a stepwise fashion. On the other hand, tooth movement in the Ti-Nb-Al group showed relatively smooth and continuous progression. At 17 days after insertion of expansion springs, there were no significant differences between the Ti-Nb-Al and Ni-Ti groups in the amount of tooth movement. These results indicate that Ti-Nb-Al wire has excellent mechanical properties for smooth, continuous tooth movement and suggest that Ti-Nb-Al wire may be used as a practical nickel-free shape memory and superelastic alloy wire for orthodontic treatment as a substitute for Ni-Ti wire.

Finite element modelling of squirrel, guinea pig and rat skulls: using geometric morphometrics to assess sensitivity.

PubMed

Cox, P G; Fagan, M J; Rayfield, E J; Jeffery, N

2011-12-01

Rodents are defined by a uniquely specialized dentition and a highly complex arrangement of jaw-closing muscles. Finite element analysis (FEA) is an ideal technique to investigate the biomechanical implications of these specializations, but it is essential to understand fully the degree of influence of the different input parameters of the FE model to have confidence in the model's predictions. This study evaluates the sensitivity of FE models of rodent crania to elastic properties of the materials, loading direction, and the location and orientation of the models' constraints. Three FE models were constructed of squirrel, guinea pig and rat skulls. Each was loaded to simulate biting on the incisors, and the first and the third molars, with the angle of the incisal bite varied over a range of 45°. The Young's moduli of the bone and teeth components were varied between limits defined by findings from our own and previously published tests of material properties. Geometric morphometrics (GMM) was used to analyse the resulting skull deformations. Bone stiffness was found to have the strongest influence on the results in all three rodents, followed by bite position, and then bite angle and muscle orientation. Tooth material properties were shown to have little effect on the deformation of the skull. The effect of bite position varied between species, with the mesiodistal position of the biting tooth being most important in squirrels and guinea pigs, whereas bilateral vs. unilateral biting had the greatest influence in rats. A GMM analysis of isolated incisor deformations showed that, for all rodents, bite angle is the most important parameter, followed by elastic properties of the tooth. The results here elucidate which input parameters are most important when defining the FE models, but also provide interesting glimpses of the biomechanical differences between the three skulls, which will be fully explored in future publications. © 2011 The Authors. Journal of Anatomy © 2011 Anatomical Society of Great Britain and Ireland.

Delayed replantation of rat teeth after use of reconstituted powdered milk as a storage medium.

PubMed

dos Santos, Cláudia Letícia Vendrame; Sonoda, Celso Koogi; Poi, Wilson Roberto; Panzarini, Sônia Regina; Sundefeld, Maria Lúcia Marçal Mazza; Negri, Márcia Regina

2009-02-01

Minimal extraoral dry storage period and moist storage for the avulsed tooth are identified as key steps for the treatment protocol of tooth replantation. Among the possible moist storage media, bovine milk has stood out because of its capacity of preserving the integrity of the periodontal ligament (PDL) fibers. This condition has attracted the attention to investigate the use of powdered milk, which is one of the presentation forms of bovine milk, as a feasible storage medium in cases of delayed tooth replantation. The aim of this study was to evaluate the healing process after delayed replantation of rat teeth stored in reconstituted powdered milk and long shelf-life (ultra high temperature) whole milk. Forty maxillary right rat incisors were assigned to four groups (n = 10): group I--the teeth were extracted and immediately replanted into theirs sockets; group II--the teeth were stored for 60 min in 200 ml of freshly reconstituted powdered milk; group III--the teeth were stored for 60 min in 200 ml of long shelf-life whole milk; group IV--the teeth were kept dry for the same time. All procedures were performed at room temperature. Next, the root canals of teeth in groups II, III, and IV were instrumented, filled with a calcium hydroxide-based paste, and replanted into their sockets. All animals received systemic antibiotic therapy and were killed by anesthetic overdose 60 days after replantation. The pieces containing the replanted teeth were removed, fixed, decalcified, and paraffin-embedded. Semi-serial 6-microm-thick sections were obtained and stained with hematoxylin and eosin for histomorphological analysis. There was statistically significant difference (P < 0.05) between groups I and IV regarding the presence of replacement resorption and PDL remnants on root surface. The powdered milk and long shelf-life whole milk presented similar results to each other and may be indicated as storage media for avulsed teeth.

Effect of iron containing supplements on rats' dental caries progression.

PubMed

Eshghi, Ar; Kowsari-Isfahan, R; Rezaiefar, M; Razavi, M; Zeighami, S

2012-01-01

Iron deficiency is the most common form of malnutrition in developing countries. Iron containing supplements have been used effectively to solve this problem. In children, because of teeth staining after taking iron drops, parents have the idea that iron drops are the cause of tooth decay; therefore, they limit this vital supplement in their children's diet. Hereby, we evaluate the histologic effect of iron containing supplements on tooth caries in rice rats with cariogenic or non-cariogenic diet. Twelve rats were selected and divided into four groups for this interventional experimental study. Four different types of dietary regimens were used for four months; group A, cariogenic diet with iron containing supplements; group B, cariogenic diet without iron containing supplements; group C, non-cariogenic diet with iron containing supplements; group D, non-cariogenic diet without iron containing supplements. After sacrificing the rats, 20-micron histological sections of their posterior teeth were prepared using the Ground Section method, then they were studied under polarized light microscopy. In order to compare the progression of caries in different samples, the depth of the lesions in the enamel was measured as three grades I, II and III. The mean grade value of A, B, C and D groups were 1.61, 2.61, 1.37 and 1.80, respectively. Statistical analysis revealed that significantly fewer caries were seen in the group which had received iron containing supplements and cariogenic diet compared with cariogenic diet without iron supplements (p<0.05). Ferrous sulfate reduces the progression of dental caries in the cariogenic dietary regimen.

Innovative evaluation of local injective gel of curcumin on the orthodontic tooth movement in rats.

PubMed

Asefi, Sohrab; Seifi, Massoud; Fard, Ghazal Hatami; Lotfi, Ali

2018-01-01

Curcumin is the most active compound in turmeric. It can suppress the nuclear factor kappa-light-chain-enhancer of activated B cells pathway and prevent the osteoclastogenesis procedure. This study aimed to be the first to evaluate the effect of curcumin on the rate of orthodontic tooth movement (OTM). Forty rats were used as follows in each group: (1) negative control: Did not receive any appliance or injection; (2) positive control: received 0.03 cc normal saline and appliance; (3) gelatin plus curcumin (G): Received 0.03 cc hydrogel and appliance; and (4) chitosan plus curcumin (Ch): Received 0.03 cc hydrogel and appliance. They were anesthetized and closed nickel-titanium coil springs were installed between the first molars and central incisors unilaterally as the orthodontic appliance. After 21 days, the rats were decapitated, and the distance between the first and second molars was measured by a leaf gauge. Howship's lacunae, blood vessels, osteoclast-like cells, and root resorption lacunae were evaluated in the histological analysis. Data were analyzed by one-way ANOVA, Tukey's test, and t -test ( P < 0.05 consider significant). No significant difference was found in OTM between groups delivered orthodontic forces. Curcumin inhibited root and bone resorption, osteoclastic recruitment, and angiogenesis significantly. Curcumin had no significant inhibitory effect on OTM. While it had a significant role on decreasing bone or root resorption ( P > 0.05).

Prevaccination with SRL172 (heat-killed Mycobacterium vaccae) inhibits experimental periodontal disease in Wistar rats

PubMed Central

Breivik, T; Rook, G A W

2000-01-01

Periodontal disease is a bacterial dental plaque-induced destructive inflammatory condition of the tooth-supporting tissues, which is thought to be mediated by T lymphocytes secreting T helper 2 (Th2) cytokines, resulting in recruitment of high numbers of antibody-producing B lymphocytes/plasma cells as well as polymorphonuclear leucocytes (PMN) secreting tissue-destructive components, such at matrix metalloproteinases and reactive oxygen metabolites into the gingival connective tissues. One treatment strategy may be to down-regulate the Th2 response to those dental plaque microorganisms which induce the destructive inflammatory response. In this study we have examined the effects of a potent down-regulator of Th2 responses on ligature-induced periodontal disease in an experimental rat model. A single s.c. injection into Wistar rats of 0·1 or 1 mg of SRL172, a preparation of heat-killed Mycobacterium vaccae (NCTC 11659), 13 days before application of the ligature, significantly reduced the subsequent destruction of the tooth-supporting tissues, as measured by loss of periodontal attachment fibres (P < 0·001) and bone (P < 0·002). This protective effect occurred not only on the experimental (ligatured) side but also on the control unligatured side. SRL172 has undergone extensive toxicological studies and safety assessments in humans, and it is suggested that it may provide a safe and novel therapeutic approach to periodontal disease. PMID:10844524

To What Extent is Primate Second Molar Enamel Occlusal Morphology Shaped by the Enamel-Dentine Junction?

PubMed Central

Gilissen, Emmanuel; Thiery, Ghislain

2015-01-01

The form of two hard tissues of the mammalian tooth, dentine and enamel, is the result of a combination of the phylogenetic inheritance of dental traits and the adaptive selection of these traits during evolution. Recent decades have been significant in unveiling developmental processes controlling tooth morphogenesis, dental variation and the origination of dental novelties. The enamel-dentine junction constitutes a precursor for the morphology of the outer enamel surface through growth of the enamel cap which may go along with the addition of original features. The relative contribution of these two tooth components to morphological variation and their respective response to natural selection is a major issue in paleoanthropology. This study will determine how much enamel morphology relies on the form of the enamel-dentine junction. The outer occlusal enamel surface and the enamel-dentine junction surface of 76 primate second upper molars are represented by polygonal meshes and investigated using tridimensional topometrical analysis. Quantitative criteria (elevation, inclination, orientation, curvature and occlusal patch count) are introduced to show that the enamel-dentine junction significantly constrains the topographical properties of the outer enamel surface. Our results show a significant correlation for elevation, orientation, inclination, curvature and occlusal complexity between the outer enamel surface and the enamel dentine junction for all studied primate taxa with the exception of four modern humans for curvature (p<0.05). Moreover, we show that, for all selected topometrical parameters apart from occlusal patch count, the recorded correlations significantly decrease along with enamel thickening in our sample. While preserving tooth integrity by providing resistance to wear and fractures, the variation of enamel thickness may modify the curvature present at the occlusal enamel surface in relation to enamel-dentine junction, potentially modifying dental functionalities such as blunt versus sharp dental tools. In terms of natural selection, there is a balance between increasing tooth resistance and maintaining efficient dental tools. In this sense the enamel cap acts as a functional buffer for the molar occlusal pattern. In primates, results suggest a primary emergence of dental novelties on the enamel-dentine junction and a secondary transposition of these novelties with no or minor modifications of dental functionalities by the enamel cap. Whereas enamel crenations have been reported by previous studies, our analysis do not support the presence of enamel tubercles without dentine relief nuclei. As is, the enamel cap is, at most, a secondary source of morphological novelty. PMID:26406597

G3139, an Anti-Bcl-2 Antisense Oligomer that Binds Heparin-Binding Growth Factors and Collagen I, Alters In Vitro Endothelial Cell Growth and Tubular Morphogenesis

PubMed Central

Stein, C.A.; Wu, SiJian; Voskresenskiy, Anatoliy M.; Zhou, Jin-Feng; Shin, Joongho; Miller, Paul; Souleimanian, Naira; Benimetskaya, Luba

2009-01-01

Purpose We examined the effects of G3139 on the interaction of heparin-binding proteins (e.g., FGF2 and collagen I) with endothelial cells. G3139 is an 18mer phosphorothioate oligonucleotide targeted to the initiation codon region of the Bcl-2 mRNA. A randomized, prospective global Phase III trial in advanced melanoma (GM301) has evaluted G3139 in combination with dacarbazine. However, the mechanism of action of G3139 is incompletely understood, as it is unlikely that Bcl-2 silencing is the sole mechanism for chemo-sensitization in melanoma cells. Experimental Design The ability of G3139 to interact with and protect heparin-binding proteins was quantitated. The effects of G3139 on the binding of FGF2 to high affinity cell surface receptors, and the induction of cellular mitogenesis and tubular morphogenesis in HMEC-1 and HUVEC cells were determined. Results G3139 binds with picomolar affinity to collagen I. By replacing heparin, the drug can potentiate the binding of FGF2 to FGFR1 IIIc, and it protects FGF from oxidation and from proteolysis. G3139 can increase endothelial cell mitogenesis and tubular morphogenesis of HMEC-1 cells in 3D collagen gels, increases the mitogenesis of HUVEC cells similarly, and induces vessel sprouts in the rat aortic ring model. Conclusions G3139 dramatically affects the behavior of endothelial cells. There may be a correlation between this observation and the treatment interaction with LDH observed clinically. PMID:19351753

Mutations in zebrafish pitx2 model congenital malformations in Axenfeld-Rieger syndrome but do not disrupt left-right placement of visceral organs.

PubMed

Ji, Yongchang; Buel, Sharleen M; Amack, Jeffrey D

2016-08-01

Pitx2 is a conserved homeodomain transcription factor that has multiple functions during embryonic development. Mutations in human PITX2 cause autosomal dominant Axenfeld-Rieger syndrome (ARS), characterized by congenital eye and tooth malformations. Pitx2(-/-) knockout mouse models recapitulate aspects of ARS, but are embryonic lethal. To date, ARS treatments remain limited to managing individual symptoms due to an incomplete understanding of PITX2 function. In addition to regulating eye and tooth development, Pitx2 is a target of a conserved Nodal (TGFβ) signaling pathway that mediates left-right (LR) asymmetry of visceral organs. Based on its highly conserved asymmetric expression domain, the Nodal-Pitx2 axis has long been considered a common denominator of LR development in vertebrate embryos. However, functions of Pitx2 during asymmetric organ morphogenesis are not well understood. To gain new insight into Pitx2 function we used genome editing to create mutations in the zebrafish pitx2 gene. Mutations in the pitx2 homeodomain caused phenotypes reminiscent of ARS, including aberrant development of the cornea and anterior chamber of the eye and reduced or absent teeth. Intriguingly, LR asymmetric looping of the heart and gut was normal in pitx2 mutants. These results suggest conserved roles for Pitx2 in eye and tooth development and indicate Pitx2 is not required for asymmetric looping of zebrafish visceral organs. This work establishes zebrafish pitx2 mutants as a new animal model for investigating mechanisms underlying congenital malformations in ARS and high-throughput drug screening for ARS therapeutics. Additionally, pitx2 mutants present a unique opportunity to identify new genes involved in vertebrate LR patterning. We show Nodal signaling-independent of Pitx2-controls asymmetric expression of the fatty acid elongase elovl6 in zebrafish, pointing to a potential novel pathway during LR organogenesis. Copyright © 2016 Elsevier Inc. All rights reserved.

Tbx1 Regulates Progenitor Cell Proliferation in the Dental Epithelium by Modulating PITX2 Activation of p21

PubMed Central

Cao, Huojun; Florez, Sergio; Amen, Melanie; Huynh, Tuong; Skobe, Ziedonis; Baldini, Antonio; Amendt, Brad A.

2012-01-01

Tbx1−/− mice present with phenotypic effects observed in DiGeorge syndrome patients however, the molecular mechanisms of Tbx1 regulating craniofacial and tooth development are unclear. Analyses of the Tbx1 null mice reveal incisor microdontia, small cervical loops and BrdU labeling reveals a defect in epithelial cell proliferation. Furthermore, Tbx1 null mice molars are lacking normal cusp morphology. Interestingly, p21 (associated with cell cycle arrest) is up regulated in the dental epithelium of Tbx1−/− embryos. These data suggest that Tbx1 inhibits p21 expression to allow for cell proliferation in the dental epithelial cervical loop, however Tbx1 does not directly regulate p21 expression. A new molecular mechanism has been identified where Tbx1 inhibits Pitx2 transcriptional activity and decreases the expression of Pitx2 target genes, p21, Lef-1 and Pitx2c. p21 protein is increased in PITX2C transgenic mouse embryo fibroblasts (MEF) and chromatin immunoprecipitation assays demonstrate endogenous Pitx2 binding to the p21 promoter. Tbx1 attenuates PITX2 activation of endogenous p21 expression and Tbx1 null MEFs reveal increased Pitx2a and activation of Pitx2c isoform expression. Tbx1 physically interacts with the PITX2 C-terminus and represses PITX2 transcriptional activation of the p21, LEF-1, and Pitx2c promoters. Tbx1−/+/Pitx2−/+ double heterozygous mice present with an extra premolar-like tooth revealing a genetic interaction between these factors. The ability of Tbx1 to repress PITX2 activation of p21 may promote cell proliferation. In addition, PITX2 regulation of p21 reveals a new role for PITX2 in repressing cell proliferation. These data demonstrate new functional mechanisms for Tbx1 in tooth morphogenesis and provide a molecular basis for craniofacial defects in DiGeorge syndrome patients. PMID:20816801

Tbx1 regulates progenitor cell proliferation in the dental epithelium by modulating Pitx2 activation of p21.

PubMed

Cao, Huojun; Florez, Sergio; Amen, Melanie; Huynh, Tuong; Skobe, Ziedonis; Baldini, Antonio; Amendt, Brad A

2010-11-15

Tbx1(-/-) mice present with phenotypic effects observed in DiGeorge syndrome patients however, the molecular mechanisms of Tbx1 regulating craniofacial and tooth development are unclear. Analyses of the Tbx1 null mice reveal incisor microdontia, small cervical loops and BrdU labeling reveals a defect in epithelial cell proliferation. Furthermore, Tbx1 null mice molars are lacking normal cusp morphology. Interestingly, p21 (associated with cell cycle arrest) is up regulated in the dental epithelium of Tbx1(-/-) embryos. These data suggest that Tbx1 inhibits p21 expression to allow for cell proliferation in the dental epithelial cervical loop, however Tbx1 does not directly regulate p21 expression. A new molecular mechanism has been identified where Tbx1 inhibits Pitx2 transcriptional activity and decreases the expression of Pitx2 target genes, p21, Lef-1 and Pitx2c. p21 protein is increased in PITX2C transgenic mouse embryo fibroblasts (MEF) and chromatin immunoprecipitation assays demonstrate endogenous Pitx2 binding to the p21 promoter. Tbx1 attenuates PITX2 activation of endogenous p21 expression and Tbx1 null MEFs reveal increased Pitx2a and activation of Pitx2c isoform expression. Tbx1 physically interacts with the PITX2 C-terminus and represses PITX2 transcriptional activation of the p21, LEF-1, and Pitx2c promoters. Tbx1(-/+)/Pitx2(-/+) double heterozygous mice present with an extra premolar-like tooth revealing a genetic interaction between these factors. The ability of Tbx1 to repress PITX2 activation of p21 may promote cell proliferation. In addition, PITX2 regulation of p21 reveals a new role for PITX2 in repressing cell proliferation. These data demonstrate new functional mechanisms for Tbx1 in tooth morphogenesis and provide a molecular basis for craniofacial defects in DiGeorge syndrome patients. Copyright © 2010 Elsevier Inc. All rights reserved.

Comparative proteomic analysis reveals heart toxicity induced by chronic arsenic exposure in rats.

PubMed

Huang, Qingyu; Xi, Guochen; Alamdar, Ambreen; Zhang, Jie; Shen, Heqing

2017-10-01

Arsenic is a widespread metalloid in the environment, which poses a broad spectrum of adverse effects on human health. However, a global view of arsenic-induced heart toxicity is still lacking, and the underlying molecular mechanisms remain unclear. By performing a comparative quantitative proteomic analysis, the present study aims to investigate the alterations of proteome profile in rat heart after long-term exposure to arsenic. As a result, we found that the abundance of 81 proteins were significantly altered by arsenic treatment (35 up-regulated and 46 down-regulated). Among these, 33 proteins were specifically associated with cardiovascular system development and function, including heart development, heart morphology, cardiac contraction and dilation, and other cardiovascular functions. It is further proposed that the aberrant regulation of 14 proteins induced by arsenic would disturb cardiac contraction and relaxation, impair heart morphogenesis and development, and induce thrombosis in rats, which is mediated by the Akt/p38 MAPK signaling pathway. Overall, these findings will augment our knowledge of the involved mechanisms and develop useful biomarkers for cardiotoxicity induced by environmental arsenic exposure. Copyright © 2017 Elsevier Ltd. All rights reserved.

Modulated regeneration of acid-etched human tooth enamel by a functionalized dendrimer that is an analog of amelogenin.

PubMed

Chen, Mei; Yang, Jiaojiao; Li, Jiyao; Liang, Kunneng; He, Libang; Lin, Zaifu; Chen, Xingyu; Ren, Xiaokang; Li, Jianshu

2014-10-01

In the bioinspired repair process of tooth enamel, it is important to simultaneously mimic the organic-matrix-induced biomineralization and increase the binding strength at the remineralization interface. In this work, a fourth-generation polyamidoamine dendrimer (PAMAM) is modified by dimethyl phosphate to obtain phosphate-terminated dendrimer (PAMAM-PO3H2) since it has a similar dimensional scale and peripheral functionalities to that of amelogenin, which plays important role in the natural development process of enamel. Its phosphate group has stronger affinity for calcium ion than carboxyl group and can simultaneously provide strong hydroxyapatite (HA)-binding capability. The MTT assay demonstrates the low cytotoxicity of PAMAM-PO3H2. Adsorption tests indicate that PAMAM-PO3H2 can be tightly adsorbed on the human tooth enamel. Scanning electron microscopy and X-ray diffraction are used to analyze the remineralization process. After being incubated in artificial saliva for 3weeks, there is a newly generated HA layer of 11.23μm thickness on the acid-etched tooth enamel treated by PAMAM-PO3H2, while the thickness for the carboxyl-terminated one (PAMAM-COOH) is only 6.02μm. PAMAM-PO3H2 can regulate the remineralization process to form ordered new crystals oriented along the Z-axis and produce an enamel prism-like structure that is similar to that of natural tooth enamel. The animal experiment also demonstrates that PAMAM-PO3H2 can induce significant HA regeneration in the oral cavity of rats. Thus PAMAM-PO3H2 shows great potential as a biomimetic restorative material for human tooth enamel. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Locally limited inhibition of bone resorption and orthodontic relapse by recombinant osteoprotegerin protein.

PubMed

Schneider, D A; Smith, S M; Campbell, C; Hayami, T; Kapila, S; Hatch, N E

2015-04-01

To determine minimal dose levels required for local inhibition of orthodontic relapse by recombinant OPG protein (OPG-Fc), while also determining effects of injected OPG-Fc on alveolar bone and long bone. The Department of Orthodontics and Pediatric Dentistry at the University of Michigan. Eighteen male Sprague Dawley rats. Maxillary molars were moved with nickel-titanium springs and then allowed to relapse in Sprague Dawley rats. Upon appliance removal, animals were injected with a single dose of 1.0 mg/kg OPG-Fc, 0.1 mg/kg OPG-Fc, or phosphate-buffered saline (vehicle) just distal to the molar teeth. Tooth movement measurements were made from stone casts, which were scanned and digitally measured. Alveolar tissues were examined by histology. Micro-computed tomography was used to quantify changes in alveolar and femur bone. Local injection of OPG-Fc inhibited molar but not incisor relapse, when compared to vehicle-injected animals. No significant differences in alveolar or femur bone were seen between the three treatment groups after 24 days of relapse. Our results demonstrate that a single local injection of OPG-Fc effectively inhibits orthodontic relapse, with minimal systemic bone metabolic effects. Our results also show that a single injection of OPG-Fc will influence tooth movement only in teeth close to the injection site. These findings indicate that OPG-Fc has potential as a safe and effective pharmacological means to locally control osteoclasts, for uses such as maintaining anchorage during orthodontic tooth movement and preventing orthodontic relapse in humans. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Industrial Noise and Tooth Wear - Experimental Study

PubMed Central

Cavacas, Maria Alzira; Tavares, Vitor; Borrecho, Gonçalo; Oliveira, Maria João; Oliveira, Pedro; Brito, José; Águas, Artur; dos Santos, José Martins

2015-01-01

Tooth wear is a complex multifactorial process that involves the loss of hard dental tissue. Parafunctional habits have been mentioned as a self-destructive process caused by stress, which results in hyperactivity of masticatory muscles. Stress manifests itself through teeth grinding, leading to progressive teeth wear. The effects of continuous exposure to industrial noise, a “stressor” agent, cannot be ignored and its effects on the teeth must be evaluated. Aims: The aim of this study was to ascertain the effects of industrial noise on dental wear over time, by identifying and quantifying crown area loss. Material and Methods: 39 Wistar rats were used. Thirty rats were divided in 3 experimental groups of 10 animals each. Animals were exposed to industrial noise, rich in LFN components, for 1, 4 and 7 months, with an average weekly exposure of 40 hours (8h/day, 5 days/week with the weekends in silence). The remaining 9 animals were kept in silence. The areas of the three main cusps of the molars were measured under light microscopy. Statistical analysis used: A two-way ANOVA model was applied at significance level of 5%. Results: The average area of the molar cusps was significantly different between exposed and non-exposed animals. The most remarkable differences occurred between month 1 and 4. The total crown loss from month 1 to month 7 was 17.3% in the control group, and 46.5% in the exposed group, and the differences between these variations were significant (p<0.001). Conclusions: Our data suggest that industrial noise is an important factor in the pathogenesis of tooth wear. PMID:25798052

Impairment of Bony Crypt Development Associated With Hexavalent Chromium Exposure During Tooth Eruption.

PubMed

Sánchez, Luciana M; Lewicki, Marianela; De Lucca, Romina C; Ubios, Ángela M

2015-12-01

Improperly treated hexavalent chromium-containing industrial wastes contaminate drinking water, potentially affecting children taking breast milk or baby bottles prepared with infant formula. Thus, the aim of the present work was to determine the effect of this toxic on bone activity in the developing alveolus during tooth eruption of suckling Wistar rats intoxicated with potassium dichromate. Experimental animals received a daily dose of 12.5mg/kg body weight of potassium dichromate by gavage for 10 days; controls received an equivalent volume of saline solution. Histologic and histomorphometric studies of the mandible were performed. The data were statistically analyzed using Student's t test; statistical significance was set at a value of p <0.05. Experimental animals exhibited delayed tooth eruption, decreased periodontal width and bone volume, a lower percentage of bone formation surfaces, and higher percentage of quiescent surfaces (p<0.05) compared to controls. The delay in tooth eruption observed after exposure to hexavalent chromium is the result of a lower rate of bone remodeling in the developing alveolus. The obtained results show the importance of controlling toxic substances in drinking water, since their effects may alter the growth and development of subjects who were exposed during early infancy. Sociedad Argentina de Investigación Odontológica.

The AMPA receptor subunit GluR1 regulates dendritic architecture of motor neurons

NASA Technical Reports Server (NTRS)

Inglis, Fiona M.; Crockett, Richard; Korada, Sailaja; Abraham, Wickliffe C.; Hollmann, Michael; Kalb, Robert G.

2002-01-01

The morphology of the mature motor neuron dendritic arbor is determined by activity-dependent processes occurring during a critical period in early postnatal life. The abundance of the AMPA receptor subunit GluR1 in motor neurons is very high during this period and subsequently falls to a negligible level. To test the role of GluR1 in dendrite morphogenesis, we reintroduced GluR1 into rat motor neurons at the end of the critical period and quantitatively studied the effects on dendrite architecture. Two versions of GluR1 were studied that differed by the amino acid in the "Q/R" editing site. The amino acid occupying this site determines single-channel conductance, ionic permeability, and other essential electrophysiologic properties of the resulting receptor channels. We found large-scale remodeling of dendritic architectures in a manner depending on the amino acid occupying the Q/R editing site. Alterations in the distribution of dendritic arbor were not prevented by blocking NMDA receptors. These observations suggest that the expression of GluR1 in motor neurons modulates a component of the molecular substrate of activity-dependent dendrite morphogenesis. The control of these events relies on subunit-specific properties of AMPA receptors.

Dental and oropharyngeal lesions in rats with chronic acid reflux esophagitis.

PubMed

Shimazu, Rintaro; Yamamoto, Mihoko; Minesaki, Akimichi; Kuratomi, Yuichiro

2018-06-01

In this study, we evaluated pathological changes in the tooth and pharynx of GERD rats to elucidate the association between gastric acid reflux and oral and pharyngeal diseases. An experimental rat model of chronic acid reflux esophagitis was surgically created. The oral cavities were observed histologically every 2 weeks until 20 weeks after surgery. At 10 weeks after surgery, molar crown heights in GERD rats were shorter than that in control rats, and inflammatory cell infiltration by gastric acid reflux was found in the periodontal mucosa of GERD rats. Furthermore, dental erosion progressed in GERD rats at 20 weeks after surgery, and enamel erosion and dentin exposure were observed. During the same period, inflammatory cell infiltration was observed in the mucosa of the posterior part of the tongue. These findings suggest that gastric acid reflux may be one of the exacerbating factors of dental erosion, periodontitis and glossitis. We investigated oral changes in an experimental rat model of GERD and observed development of dental erosion, periodontitis and glossitis. Our findings suggested chronic gastric acid reflux may be involved in the pathogenesis of oral disease. Copyright © 2017 Elsevier B.V. All rights reserved.

Nitrofen interferes with trophoblastic expression of retinol-binding protein and transthyretin during lung morphogenesis in the nitrofen-induced congenital diaphragmatic hernia model.

PubMed

Kutasy, Balazs; Gosemann, Jan H; Doi, Takashi; Fujiwara, Naho; Friedmacher, Florian; Puri, Prem

2012-02-01

Retinoids play a key role in lung development. Retinoid signaling pathway has been shown to be disrupted in the nitrofen model of congenital diaphragmatic hernia (CDH) but the exact mechanism is not clearly understood. Retinol-binding protein (RBP) and transthyretin (TTR) are transport proteins for delivery of retinol to the tissues via circulation. Previous studies have shown that pulmonary retinol levels are decreased during lung morphogenesis in the nitrofen CDH model. In human newborns with CDH, both retinol and RBP levels are decreased. It has been reported that maternal RBP does not cross the placenta and the fetus produces its own RBP by trophoblast. RBP and TTR synthesized in the fetus are essential for retinol transport to the developing organs including lung morphogenesis. We hypothesized that nitrofen interferes with the trophoblastic expression of RBP and TTR during lung morphogenesis and designed this study to examine the trophoblastic expression of RBP and TTR, and the total level of RBP and TTR in the lung in the nitrofen model of CDH. Pregnant rats were exposed to either olive oil or nitrofen on day 9 of gestation (D9). Fetal lungs and placenta harvested on D21 and divided into two groups: control (n = 8) and nitrofen with CDH (n = 8). Total lung RBP and TTR levels using protein extraction were compared with enzyme linked immunoassay (ELISA). Immunohistochemistry was performed to evaluate trophoblastic RBP and TTR expression. Total protein levels of lung RBP and TTR were significantly lower in CDH (0.26 ± 0.003 and 6.4 ± 0.5 μg/mL) compared with controls (0.4 ± 0.001 and 9.9 ± 1.6 μg/mL, p < 0.05). In the control group, immunohistochemical staining showed strong immunoreactivity of RBP and TTR in the trophoblast compared to CDH group. Decreased trophoblast expression of retinol transport proteins suggest that nitrofen may interfere with the fetal retinol transport resulting in reduced pulmonary RBP and TTR levels and causing pulmonary hypoplasia in CDH.

Development of the septal region in the rat. II. Morphogenesis in normal and x-irradiated embryos

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

Bayer, S.A.

1979-01-01

Morphogenesis of the septal region was examined in normal rat embryos from embryonic day (E) 10 to E22. The greater part of the septal region is postulated to form from two separate anlagen which can be clearly distinguished in the telencephalon by E13 and E14. One lies in the anterior ventromedial wall and presumably forms the nucleus of the diagonal band, medial, lateral, and triangular septal nuclei. The other lies in the posterior ventrolateral ridge and presumably forms the bed nuclei of the stria terminalis and the anterior commissure. On E15, the early differentiating cells in these anlagen fuse inmore » the same region where the anterior commissure will cross on E17. On E16 and E17, a prominent subependymal zone develops in the anterior septal region and presumably gives rise to the nucleus accumbens. A quantitative analysis was made of three cell zones (neuroepithelium, subependymal zone, differentiating cell zone) at coronal levels through the developing nucleus accumbens and the nucleus of the diagonal band (anterior level) and the medial and lateral septal nuclei (middle and posterior levels). To accurately locate regions of primitive mitotic and migratory cells within the zones at each level, the number of cells surviving a single exposure to 200 R x-rays in embryonic brains (E15 to E22) were compared with controls. Each zone responded differently to x-ray insult. The radiosensitivity of the neuroepithelium decreases significantly after E19; the subependymal zone is highly radiosensitive throughout; the differentiating cell zone is radioresistant throughout. The significance of these findings is discussed in the light of the autoradiographic determination of the time of formation of septal neurons.« less

Impact of maternal and postnatal zinc dietary status on the prostate of pubescent and adult rats.

PubMed

Camora, Lucas F; Silva, Ana Priscila G; Santos, Sérgio A A; Justulin, Luis A; Perobelli, Juliana E; Barbisan, Luis Fernando; Scarano, Wellerson R

2017-11-01

Zinc is important for cell physiology and alteration of its levels during development can modulate a series of biological events. The aim of this study was to investigate whether dietary zinc deficiency or supplementation during morphogenesis and early postnatal development could interfere in prostate maturation. Pregnant rats were exposed to a standard diet (NZ:35 mg Zn/kg chow), low-zinc diet (LZ:3 mg of Zn/kg chow) and zinc-supplemented diet (HZ:180 mg/Kg chow) from gestational day 10 (GD10) through postnatal day 21 (PND21). After weaning, male offspring were divided into three groups that were submitted to the same food conditions as their mothers until PND53. The animals were euthanized at PND53 and PND115. The ventral prostate was removed, weighed and its fragments were subjected to histological, western blot and zymography analysis. PND53: body and prostate weight were lower in LZ compared to NZ; the epithelial compartment was reduced while the stromal compartment was increased in LZ compared to NZ; there was an increase in the amount of collagen and reduction in AR and SIRT1 expression in LZ compared to NZ. PND115: body weight was lower in LZ compared to NZ and prostate weight was similar among the groups; peripheral physiological hyperplasia was observed, as well as an increased epithelial proliferation index and reduced PAR4 expression in LZ and HZ compared to NZ. Zinc deficiency during prostate morphogenesis and differentiation is potentially harmful to its morphology, however, by restoring the standard dietary environment, the gland responds to the new microenvironment independent of the previous dietary condition. © 2017 International Federation for Cell Biology.

Embryonic essential myosin light chain regulates fetal lung development in rats.

PubMed

Santos, Marta; Moura, Rute S; Gonzaga, Sílvia; Nogueira-Silva, Cristina; Ohlmeier, Steffen; Correia-Pinto, Jorge

2007-09-01

Congenital diaphragmatic hernia (CDH) is currently the most life-threatening congenital anomaly the major finding of which is lung hypoplasia. Lung hypoplasia pathophysiology involves early developmental molecular insult in branching morphogenesis and a late mechanical insult by abdominal herniation in maturation and differentiation processes. Since early determinants of lung hypoplasia might appear as promising targets for prenatal therapy, proteomics analysis of normal and nitrofen-induced hypoplastic lungs was performed at 17.5 days after conception. The major differentially expressed protein was identified by mass spectrometry as myosin light chain 1a (MLC1a). Embryonic essential MLC1a and regulatory myosin light chain 2 (MLC2) were characterized throughout normal and abnormal lung development by immunohistochemistry and Western blot. Disruption of MLC1a expression was assessed in normal lung explant cultures by antisense oligodeoxynucleotides. Since early stages of normal lung development, MLC1a was expressed in vascular smooth muscle (VSM) cells of pulmonary artery, and MLC2 was present in parabronchial smooth muscle and VSM cells of pulmonary vessels. In addition, early smooth muscle differentiation delay was observed by immunohistochemistry of alpha-smooth muscle actin and transforming growth factor-beta1. Disruption of MLC1a expression during normal pulmonary development led to significant growth and branching impairment, suggesting a role in branching morphogenesis. Both MLC1a and MLC2 were absent from hypoplastic fetal lungs during pseudoglandular stage of lung development, whereas their expression partially recovered by prenatal treatment with vitamin A. Thus, a deficiency in contractile proteins MLC1a and MLC2 might have a role among the early molecular determinants of lung hypoplasia in the rat model of nitrofen-induced CDH.

Patterns of immunoreactivity specific for gustducin and for NCAM differ in developing rat circumvallate papillae and their taste buds.

PubMed

Iwasaki, Shin-Ichi; Aoyagi, Hidekazu; Asami, Tomoichiro; Wanichanon, Chaitip; Jackowiak, Hanna

2012-05-01

α-Gustducin and neural cell adhesion molecule (NCAM) are molecules previously found to be expressed in different cell types of mammalian taste buds. We examined the expression of α-gustducin and NCAM during the morphogenesis of circumvallate papillae and the formation of their taste buds by immunofluorescence staining and laser-scanning microscopy of semi-ultrathin sections of fetal and juvenile rat tongues. Images obtained by confocal laser scanning microscopy in transmission mode were also examined to provide outlines of histology and cell morphology. Morphogenesis of circumvallate papillae had already started on embryonic day 13 (E13) and was evident as the formation of placode. By contrast, taste buds in the circumvallate papillae started to appear between postnatal day 0 (P0) and P7. Although no cells with immunoreactivity specific for α-gustducin were detected in fetuses from E13 to E19, cells with NCAM-specific immunoreactivity were clearly apparent in the entire epithelium of the circumvallate papillary placode, the rudiment of each circumvallate papilla and the developing circumvallate papilla itself from E13 to E19. However, postnatally, both α-gustducin and NCAM became concentrated within taste cells as the formation of taste buds advanced. After P14, neither NCAM nor α-gustducin was detectable in the epithelium around the taste buds. In conclusion, α-gustducin appeared in the cytoplasm of taste cells during their formation after birth, while NCAM appeared in the epithelium of the circumvallate papilla-forming area. However, these two markers of taste cells were similarly distributed within mature taste cells. Copyright © 2011 Elsevier GmbH. All rights reserved.

The polarity protein partitioning-defective 1 (PAR-1) regulates dendritic spine morphogenesis through phosphorylating postsynaptic density protein 95 (PSD-95).

PubMed

Wu, Qian; DiBona, Victoria L; Bernard, Laura P; Zhang, Huaye

2012-08-31

The polarity protein PAR-1 plays an essential role in many cellular contexts, including embryogenesis, asymmetric cell division, directional migration, and epithelial morphogenesis. Despite its known importance in different cellular processes, the role of PAR-1 in neuronal morphogenesis is less well understood. In particular, its role in the morphogenesis of dendritic spines, which are sites of excitatory synaptic inputs, has been unclear. Here, we show that PAR-1 is required for normal spine morphogenesis in hippocampal neurons. We further show that PAR-1 functions through phosphorylating the synaptic scaffolding protein PSD-95 in this process. Phosphorylation at a conserved serine residue in the KXGS motif in PSD-95 regulates spine morphogenesis, and a phosphomimetic mutant of this site can rescue the defects of kinase-dead PAR-1. Together, our findings uncover a role of PAR-1 in spine morphogenesis in hippocampal neurons through phosphorylating PSD-95.

Innovative evaluation of local injective gel of curcumin on the orthodontic tooth movement in rats

PubMed Central

Asefi, Sohrab; Seifi, Massoud; Fard, Ghazal Hatami; Lotfi, Ali

2018-01-01

Background: Curcumin is the most active compound in turmeric. It can suppress the nuclear factor kappa-light-chain-enhancer of activated B cells pathway and prevent the osteoclastogenesis procedure. This study aimed to be the first to evaluate the effect of curcumin on the rate of orthodontic tooth movement (OTM). Materials and Methods: Forty rats were used as follows in each group: (1) negative control: Did not receive any appliance or injection; (2) positive control: received 0.03 cc normal saline and appliance; (3) gelatin plus curcumin (G): Received 0.03 cc hydrogel and appliance; and (4) chitosan plus curcumin (Ch): Received 0.03 cc hydrogel and appliance. They were anesthetized and closed nickel-titanium coil springs were installed between the first molars and central incisors unilaterally as the orthodontic appliance. After 21 days, the rats were decapitated, and the distance between the first and second molars was measured by a leaf gauge. Howship's lacunae, blood vessels, osteoclast-like cells, and root resorption lacunae were evaluated in the histological analysis. Data were analyzed by one-way ANOVA, Tukey's test, and t-test (P < 0.05 consider significant). Results: No significant difference was found in OTM between groups delivered orthodontic forces. Curcumin inhibited root and bone resorption, osteoclastic recruitment, and angiogenesis significantly. Conclusion: Curcumin had no significant inhibitory effect on OTM. While it had a significant role on decreasing bone or root resorption (P > 0.05). PMID:29497446

Floral morphology and morphogenesis in Camptotheca (Nyssaceae), and its systematic significance.

PubMed

Gong, Jing-Zhi; Li, Qiu-Jie; Wang, Xi; Ma, Yue-Ping; Zhang, Xiao-Hui; Zhao, Liang; Chang, Zhao-Yang; Ronse De Craene, Louis

2018-03-22

Camptotheca is endemic to China and there are limited data about the breeding system and morphogenesis of the flowers. Camptotheca is thought to be related to Nyssa and Davidia in Nyssaceae, which has sometimes been included in Cornaceae. However, molecular phylogenetic studies confirmed the inclusion of Camptotheca in Nyssaceae and its exclusion from Cornaceae. The aim of this study was to reveal developmental features of the inflorescence and flowers in Camptotheca to compare with related taxa in Cornales. Inflorescences and flowers of Camptotheca acuminata at all developmental stages were collected and studied with a scanning electron microscope and stereo microscope. Camptotheca has botryoids which are composed of several capitate floral units (FUs) that are initiated acropetally. On each FU, flowers are grouped in dyads that are initiated acropetally. All floral organs are initiated centripetally. Calyx lobes are restricted to five teeth. The hypanthium, with five toothed calyx lobes, is adnate to the ovary. The five petals are free and valvate. Ten stamens are inserted in two whorls around the central depression, in which the style is immersed. Three carpels are initiated independently but the ovary is syncarpous and unilocular. The ovule is unitegmic and heterotropous. Inflorescences are functionally andromonoecious varying with the position of the FUs on the inflorescence system. Flowers on the upper FU often have robust styles and fully developed ovules. Flowers on the lower FU have undeveloped styles and aborted ovules, and the flowers on the middle FU are transitional. Camptotheca possesses several traits that unify it with Nyssa, Mastixia and Diplopanax. Inflorescence and floral characters support a close relationship with Nyssaceae and Mastixiaceae but a distant relationship with Cornus. Our results corroborate molecular inferences and support a separate family Nyssaceae.

The DP-1 transcription factor is required for keratinocyte growth and epidermal stratification.

PubMed

Chang, Wing Y; Bryce, Dawn M; D'Souza, Sudhir J A; Dagnino, Lina

2004-12-03

The epidermis is a stratified epithelium constantly replenished through the ability of keratinocytes in its basal layer to proliferate and self-renew. The epidermis arises from a single-cell layer ectoderm during embryogenesis. Large proliferative capacity is central to ectodermal cell and basal keratinocyte function. DP-1, a heterodimeric partner of E2F transcription factors, is highly expressed in the ectoderm and all epidermal layers during embryogenesis. To investigate the role of DP-1 in epidermal morphogenesis, we inhibited DP-1 activity through exogenous expression of a dominant-negative mutant (dnDP-1). Expression of the dnDP-1 mutant interferes with binding of E2F/DP-1 heterodimers to DNA and inhibits DNA replication, as well as cyclin A mRNA and protein expression. Chromatin immunoprecipitation analysis demonstrated that the cyclin A promoter is predominantly bound in proliferating keratinocytes by complexes containing E2F-3 and E2F-4. Thus, the mechanisms of decreased expression of cyclin A in the presence of dnDP-1 seem to involve inactivation of DP-1 complexes containing E2F-3 and E2F-4. To assess the consequences on epidermal morphogenesis of inhibiting DP-1 activity, we expressed dnDP-1 in rat epithelial keratinocytes in organotypic culture and observed that DP-1 inhibition negatively affected stratification of these cells. Likewise, expression of dnDP-1 in embryonic ectoderm explants produced extensive disorganization of subsequently formed epidermal basal and suprabasal layers, interfering with normal epidermal formation. We conclude that DP-1 activity is required for normal epidermal morphogenesis and ectoderm-to-epidermis transition.

Nitrofen increases total retinol levels in placenta during lung morphogenesis in the nitrofen model of congenital diaphragmatic hernia.

PubMed

Kutasy, Balazs; Pes, Lara; Friedmacher, Florian; Paradisi, Francesca; Puri, Prem

2014-10-01

It has been shown that pulmonary retinol level is decreased during lung morphogenesis in the nitrofen-induced PH in congenital diaphragmatic hernia (CDH). Placenta has a major role in the retinol homeostasis in fetal life. Since there is no fetal retinol synthesis, maternal retinol has to cross the placenta. Placenta is the main fetal retinol store where retinol is stored in retinyl-ester formation. Trophoblasts have to produce its own retinol-binding protein (RBP) for retinol transport from placenta to fetus. Recently, we demonstrated that trophoblastic RBP expression is decreased in the nitrofen model of CDH. The aim of this study was to investigate the retinol transfer from mother to the placenta in nitrofen model of CDH. Pregnant rats were exposed to either olive oil or nitrofen on day 9 of gestation (D9). Fetal placenta harvested on D21 and divided into two groups: control (n = 11) and nitrofen with CDH (n = 11). Retinoid levels in placenta were measured using HPLC. Immunohistochemistry was performed to evaluate trophoblastic expression of main RSP genes. Total retinol levels in the placenta were significantly increased in CDH placenta compared to control placenta. The retinyl-ester levels were significantly increased in CDH placenta compared to control placenta. Markedly, decreased immunoreactivity of retinoid signaling pathway was observed in trophoblast cells in CDH compared to control placenta. Increased placental retinol levels show that retinol is transferred from mother to placenta and stored in the placenta in nitrofen model of CDH during lung morphogenesis. Nitrofen may disturb the mobilization of retinol from placenta to fetal circulation causing PH in CDH.

The effects of binge-pattern alcohol consumption on orthodontic tooth movement

PubMed Central

de Araujo, Cristiano Miranda; Johann, Aline Cristina Batista Rodrigues; Camargo, Elisa Souza; Tanaka, Orlando Motohiro

2014-01-01

OBJECTIVE: This study aimed to assess tissue changes during orthodontic movement after binge-pattern ethanol 20% exposure. METHODS: Male Wistar rats (n = 54) were divided into two groups. The control group (CG) received 0.9% saline solution, while the experimental group (EG) received 20% ethanol in 0.9% saline solution (3 g/kg/day). On the 30th day, a force of 25 cN was applied with a nickel-titanium closed coil spring to move the maxillary right first molar mesially. The groups were further divided into three subgroups (2, 14 and 28 days). Tartrate-resistant acid phosphatase and picrosirius were used to assess bone resorption and neoformation, respectively. Data were compared by two-way ANOVA, Tukey's HSD, Games-Howell and chi-square test. Significance level was set at 5%. RESULTS: There was a decrease in the number of osteoclasts in EG at day 28. The percentage of collagen showed no interaction between group and time. CONCLUSION: Binge-pattern 20% ethanol promoted less bone resorption at the end of tooth movement, thereby suggesting delay in tooth movement. PMID:25628085

Carcinogenicity assessment of the Hedgehog pathway inhibitor, vismodegib in Tg.rasH2 mice and Sprague-Dawley rats.

PubMed

Li, Jinze; Morinello, Eric; Larsen, Thomas; Frost, Denzil; Caro, Ivor; Gould, Stephen; Wong, Lisa; Hendricks, Angela; Dybdal, Noel; Dambach, Donna; Schutten, Melissa

2018-02-01

Vismodegib (also known as GDC-0449) is a novel small molecule inhibitor of the Hedgehog (Hh) signaling pathway currently approved for the treatment of metastatic or locally advanced basal cell carcinoma (BCC) in humans. Its tumorigenic potential was assessed in dedicated carcinogenicity studies in rasH2 transgenic (Tg.rasH2) mice and Sprague Dawley (SD) rats. Tumorigenicity potential of vismodegib was identified in rats only and was limited to benign hair follicle tumors, including pilomatricomas and keratoacanthomas at exposures of ≥0.1-fold and ≥0.6-fold, respectively, of the steady-state exposure (AUC 0-24h ) of the recommended human dose. No malignant tumors were identified in either species. Overall, the totality of pharmacology and nonclinical safety data (lack of genotoxicity, in vitro secondary pharmacological binding, and immunoregulatory effects, and limited effects on the endocrine system) suggests that the development of the benign hair follicle tumors may be related to pharmacologically-mediated disruption of hair follicle morphogenesis, although the exact mechanism of tumorigenesis is unclear. Hair follicle tumors have not been reported in vismodegib-treated patients. The relevance of this finding in rats to patients is uncertain. Copyright © 2018 Elsevier Inc. All rights reserved.

Effects of mangosteen peel extract combined with demineralized freeze-dried bovine bone xenograft on osteocalcin, collagen 1, and osteoblast as alveolar bone regeneration in socket preservation.

PubMed

Kresnoadi, Utari; Raharjo, Tika; Rostiny, Rostiny

2018-01-01

Tooth extraction will provoke changes in alveolar bone morphology and dimensions. Postextraction bone resorption can lead to significant problems for restorative dentistry. Therefore, the extracted tooth socket needs to be preserved to reduce alveolar ridge bone resorption. This research aimed to analyze the expression and levels of osteocalcin, collagen 1, and osteoblasts in extracted tooth sockets filled with a combination of mangosteen peel extract and demineralized freeze-dried bovine bone xenograft (DFDBBX). Fifty-six Cavia cobaya , whose lower left incisors had been extracted, were divided into eight groups according to the substance used to fill their sockets on days 7 and 30, Poly ethylene glycol, DFDBBX, mangosteen peel extract, or a combination of mangosteen peel extract and DFDBBX. This research was conducted in several stages; the application of mangosteen peel extract combined with graft material was performed as the form of tooth extraction socket preservation. The C. cobaya rats were subsequently examined by immunohistochemical methods to measure osteocalcin and collagen 1 expressions, whereas histological examination was conducted to calculate the number of osteoblasts in accordance with the duration of the research. On days 7 and 30, the group treated with a combination of DFDBBX and mangosteen peel extract which had the highest expression and levels of osteocalcin, collagen 1, and osteoblasts. The administration of mangosteen peel extract combined with DFDBBX as a means of tooth extraction socket preservation can increase osteocalcin and collagen 1 expression. Consequently, osteoblasts as a means of alveolar bone regeneration will increase in number.

BoneCeramic graft regenerates alveolar defects but slows orthodontic tooth movement with less root resorption.

PubMed

Ru, Nan; Liu, Sean Shih-Yao; Bai, Yuxing; Li, Song; Liu, Yunfeng; Wei, Xiaoxia

2016-04-01

BoneCeramic (Straumann, Basel, Switzerland) can regenerate bone in alveolar defects after tooth extraction, but it is unknown whether it is feasible to move a tooth through BoneCeramic grafting sites. The objective of this study was to investigate 3-dimensional real-time root resorption and bone responses in grafted sites during orthodontic tooth movement. Sixty 5-week-old rats were randomly assigned to 3 groups to receive BoneCeramic, natural bovine cancellous bone particles (Bio-Oss; Geistlich Pharma, Wolhusen, Switzerland), or no graft, after the extraction of the maxillary left first molar. After 4 weeks, the maxillary left second molar was moved into the extraction site for 28 days. Dynamic bone microstructures and root resorption were evaluated using in-vivo microcomputed tomography. Stress distribution and corresponding tissue responses were examined by the finite element method and histology. Mixed model analysis of variance was performed to compare the differences among time points with Bonferroni post-hoc tests at the significance level of P <0.05. The BoneCeramic group had the least amount of tooth movement and root resorption volumes and craters, and the highest bone volume fraction, trabecular number, and mean trabecular thickness, followed by the Bio-Oss and the control groups. The highest stress accumulated in the cervical region of the mesial roots. BoneCeramic has better osteoconductive potential and induces less root resorption compared with Bio-Oss grafting and naturally recovered extraction sites. Copyright © 2016 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

The Polarity Protein Partitioning-defective 1 (PAR-1) Regulates Dendritic Spine Morphogenesis through Phosphorylating Postsynaptic Density Protein 95 (PSD-95)*

PubMed Central

Wu, Qian; DiBona, Victoria L.; Bernard, Laura P.; Zhang, Huaye

2012-01-01

The polarity protein PAR-1 plays an essential role in many cellular contexts, including embryogenesis, asymmetric cell division, directional migration, and epithelial morphogenesis. Despite its known importance in different cellular processes, the role of PAR-1 in neuronal morphogenesis is less well understood. In particular, its role in the morphogenesis of dendritic spines, which are sites of excitatory synaptic inputs, has been unclear. Here, we show that PAR-1 is required for normal spine morphogenesis in hippocampal neurons. We further show that PAR-1 functions through phosphorylating the synaptic scaffolding protein PSD-95 in this process. Phosphorylation at a conserved serine residue in the KXGS motif in PSD-95 regulates spine morphogenesis, and a phosphomimetic mutant of this site can rescue the defects of kinase-dead PAR-1. Together, our findings uncover a role of PAR-1 in spine morphogenesis in hippocampal neurons through phosphorylating PSD-95. PMID:22807451

Effects of near-infrared LED therapy on experimental tooth replantation in rats.

PubMed

Pigatto Mitihiro, Débora; de Paula Ramos, Solange; Corazza Montero, Janaína; Alves Campos, Aline; de Oliveira Toginho Filho, Dari; Dezan Garbelini, Cassia Cilene

2017-02-01

Dental avulsion damages periodontal tissues and may induce dentoalveolar ankylosis and root resorption after replantation. The aim of this work was to evaluate the effects of light-emitting diode (LED) therapy after tooth replantation. The upper right incisors of 36 male Wistar rats were extracted and replanted after 15 min. The control group (Co, n = 18) was submitted to replantation and the LED group (n = 18) was submitted to replantation and LED therapy (940 nm, 4 J cm -2 ) for three consecutive days (0, 24, and 48 h). Six animals from each group were euthanized at 7, 14, and 21 days for histological analysis. The upper left incisors were used as a negative control. Data were compared using the Fisher exact test, considering P < 0.05. After 7 days, the Co (73.3%) and LED (72.2%) groups presented areas of periodontal ligament necrosis. However, periodontal ligament necrosis was more frequent in the LED group at 14 (70%, P < 0.05) and 21 days (43.2%, P < 0.05) in relation to the Co group (33 and 21.6%). Inflammatory cell infiltration was more frequent in the Co group at 7 days (100%) than the LED group (24.4%, P < 0.05), but increased in the LED group after 21 days (83.3%, P < 0.05). Bone necrosis was more frequent in the LED group after 14 (79%, P < 0.05) and 21 days (60%, P < 0.005) than in the Co group (45% and 20%). Bone repair was evident in the Co group at 14 days. All of the replanted teeth had pulp necrosis. The results suggest that the application of LED therapy up to 48 h after tooth replantation may delay periodontal ligament repair. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Early embryonic brain development in rats requires the trophic influence of cerebrospinal fluid.

PubMed

Martin, C; Alonso, M I; Santiago, C; Moro, J A; De la Mano, A; Carretero, R; Gato, A

2009-11-01

Cerebrospinal fluid has shown itself to be an essential brain component during development. This is particularly evident at the earliest stages of development where a lot of research, performed mainly in chick embryos, supports the evidence that cerebrospinal fluid is involved in different mechanisms controlling brain growth and morphogenesis, by exerting a trophic effect on neuroepithelial precursor cells (NPC) involved in controlling the behaviour of these cells. Despite it being known that cerebrospinal fluid in mammals is directly involved in corticogenesis at fetal stages, the influence of cerebrospinal fluid on the activity of NPC at the earliest stages of brain development has not been demonstrated. Here, using "in vitro" organotypic cultures of rat embryo brain neuroepithelium in order to expose NPC to or deprive them of cerebrospinal fluid, we show that the neuroepithelium needs the trophic influence of cerebrospinal fluid to undergo normal rates of cell survival, replication and neurogenesis, suggesting that NPC are not self-sufficient to induce their normal activity. This data shows that cerebrospinal fluid is an essential component in chick and rat early brain development, suggesting that its influence could be constant in higher vertebrates.

Neuroplastic changes in the sensorimotor cortex associated with orthodontic tooth movement in rats.

PubMed

Sood, Mandeep; Lee, Jye-Chang; Avivi-Arber, Limor; Bhatt, Poolak; Sessle, Barry J

2015-07-01

Orthodontic tooth movement (OTM) causes transient pain and changes in the dental occlusion that may lead to altered somatosensory inputs and patterns of mastication. This study used intracortical microstimulation (ICMS) and electromyographic (EMG) recordings to test whether neuroplastic changes occur in the ICMS-defined motor representations of left and right anterior digastric (LAD, RAD), masseter, buccinator, and genioglossus (GG) muscles within the rat's face primary motor cortex (face-M1) and adjacent face primary somatosensory cortex (face-S1) during OTM. Analyses included any changes in the number of ICMS sites representing these muscles and in the onset latencies of ICMS-evoked responses in the muscles. Sprague-Dawley rats were divided into experimental (E), sham (S), and naive (N) groups; OTM was induced in the E group. Statistical analyses involved a mixed model repeated-measures analysis of variance (MMRM ANOVA). OTM resulted in significant neuroplastic changes in the number of positive sites in the E group for LAD, RAD, and GG muscles in face-M1 and face-S1 at days 1, 7, and 28 of continuous orthodontic force application, and in the number of sites in face-M1 from which ICMS could simultaneously evoke EMG responses in different combinations of LAD, RAD, and GG muscles. However, the onset latencies of ICMS-evoked responses were not significantly different between groups or between face-M1 and face-S1. The neuroplastic changes documented in this study may reflect adaptive sensorimotor changes in response to the altered environment in the oral cavity induced by OTM. © 2015 Wiley Periodicals, Inc.

Effect of Iron Containing Supplements on Rats’ Dental Caries Progression

PubMed Central

Eshghi, AR.; Kowsari-Isfahan, R.; Rezaiefar, M.; Razavi, M.; Zeighami, S.

2012-01-01

Objective: Iron deficiency is the most common form of malnutrition in developing countries. Iron containing supplements have been used effectively to solve this problem. In children, because of teeth staining after taking iron drops, parents have the idea that iron drops are the cause of tooth decay; therefore, they limit this vital supplement in their children’s diet. Hereby, we evaluate the histologic effect of iron containing supplements on tooth caries in rice rats with cariogenic or non-cariogenic diet. Materials and Methods: Twelve rats were selected and divided into four groups for this interventional experimental study. Four different types of dietary regimens were used for four months; group A, cariogenic diet with iron containing supplements; group B, cariogenic diet without iron containing supplements; group C, non-cariogenic diet with iron containing supplements; group D, non-cariogenic diet without iron containing supplements. After sacrificing the rats, 20-micron histological sections of their posterior teeth were prepared using the Ground Section method, then they were studied under polarized light microscopy. In order to compare the progression of caries in different samples, the depth of the lesions in the enamel was measured as three grades I, II and III. Results: The mean grade value of A, B, C and D groups were 1.61, 2.61, 1.37 and 1.80, respectively. Statistical analysis revealed that significantly fewer caries were seen in the group which had received iron containing supplements and cariogenic diet compared with cariogenic diet without iron supplements (p<0.05). Conclusion: Ferrous sulfate reduces the progression of dental caries in the cariogenic dietary regimen. PMID:22924097

Effects of coffee intake and intraperitoneal caffeine on bone repair process--a histologic and histometric study.

PubMed

Macedo, Rander Moreira; Brentegani, Luiz Guilherme; Lacerda, Suzie Aparecida de

2015-01-01

Studies have suggested that caffeine acts on bone promoting an increase of calcium excretion, inhibition of osteoblast proliferation and delay in tissue repair process, raising the risk of fractures, osteoporosis, periodontal disease and affecting the success of bone reconstructive procedures. The aim of this study was to analyze histomorphometrically the process of alveolar bone healing after tooth extraction in rats subjected to daily intake of boiled coffee or intraperitoneal administration of caffeine. Forty-five male rats were divided according to the treatment in Control group (C); Coffee group (CO) - treated with coffee since birth; and Caffeine (CAF) - intraperitoneal injection of aqueous solution of caffeine 1.5% (0.2 mL/100g body weight) for 30 days. When weighing between 250-300 g they were anesthetized, subjected to extraction of the maxillary right incisor, and euthanized 7, 21 and 42 days after surgery for histological assessments of bone volume and the quality of formed bone in the dental socket. The qualitative results demonstrated larger amounts of blood clot and immature bone in animals under treatment of pure caffeine compared to coffee and control. Histometric analysis revealed that coffee treatment led to a 40% drop in bone formation, and caffeine a 60% drop in comparison to control animals (ANOVA p≤0.01). It was concluded that both the daily ingestion of coffee and the intraperitoneal administration of caffeine in rats delayed the alveolar bone reparative process after tooth extraction, and this effect was more aggressive when pure caffeine was used.

Physics and the canalization of morphogenesis: a grand challenge in organismal biology

PubMed Central

von Dassow, Michelangelo; Davidson, Lance A.

2011-01-01

Morphogenesis takes place in a background of organism-to-organism and environmental variation. Therefore, a fundamental question in the study of morphogenesis is how the mechanical processes of tissue movement and deformation are affected by that variability, and in turn, how the mechanics of the system modulates phenotypic variation. We highlight a few key factors, including environmental temperature, embryo size, and environmental chemistry that might perturb the mechanics of morphogenesis in natural populations. Then we discuss several ways in which mechanics – including feedback from mechanical cues – might influence intra-specific variation in morphogenesis. To understand morphogenesis it will be necessary to consider whole-organism, environment, and evolutionary scales because these larger scales present the challenges that developmental mechanisms have evolved to cope with. Studying the variation organisms express and the variation organisms experience will aid in deciphering the causes of birth defects. PMID:21750364

Biomechanics of a Bone-Periodontal Ligament-Tooth Fibrous Joint

PubMed Central

Lin, Jeremy D.; Özcoban, Hüseyin; Greene, Janelle; Jang, Andrew T.; Djomehri, Sabra; Fahey, Kevin; Hunter, Luke; Schneider, Gerold A; Ho, Sunita P.

2013-01-01

This study investigates bone-tooth association under compression to identify strain amplified sites within the bone-periodontal ligament (PDL)-tooth fibrous joint. Our results indicate that the biomechanical response of the joint is due to a combinatorial response of constitutive properties of organic, inorganic, and fluid components. Second maxillary molars within intact maxillae (N=8) of 5-month-old rats were loaded with a μ-XCT-compatible in situ loading device at various permutations of displacement rates (0.2, 0.5, 1.0, 1.5, 2.0 mm/min) and peak reactionary load responses (5, 10, 15, 20 N). Results indicated a nonlinear biomechanical response of the joint, in which the observed reactionary load rates were directly proportional to displacement rates (velocities). No significant differences in peak reactionary load rates at a displacement rate of 0.2 mm/min were observed. However, for displacement rates greater than 0.2 mm/min, an increasing trend in reactionary rate was observed for every peak reactionary load with significant increases at 2.0 mm/min. Regardless of displacement rates, two distinct behaviors were identified with stiffness (S) and reactionary load rate (LR) values at a peak load of 5 N (S5 N=290–523 N/mm) being significantly lower than those at 10 N (LR5 N=1–10 N/s) and higher (S10N–20 N=380–684 N/mm; LR10N–20 N=1–19 N/s). Digital image correlation revealed the possibility of a screw-like motion of the tooth into the PDL-space, i.e., predominant vertical displacement of 35 μm at 5 N, followed by a slight increase to 40 μm at 10 N and 50 μm at 20 N of the tooth and potential tooth rotation at loads above 10 N. Narrowed and widened PDL spaces as a result of tooth displacement indicated areas of increased apparent strain within the complex. We propose that such highly strained regions are “hot spots” that can potentiate local tissue adaptation under physiological loading and adverse tissue adaptation under pathological loading conditions. PMID:23219279

The lining of the gut in the developing rat embryo. Its relation to the hypoblast (primary endoderm) and the notochord.

PubMed

Lamers, W H; Spliet, W G; Langemeyer, R A

1987-01-01

A light microscopical study of the morphogenesis of the gut in the rat embryo was undertaken to provide a careful map of temporal changes in the topographical relations of the (definitive) endoderm, the notochord and the hypoblast (primary endoderm). The borderline between the (definitive) endoderm and the hypoblast that appears upon gastrulation defines the lateral extension of the future gut epithelium. Within this initially semiglobular disk, the foregut and hindgut originate sequentially as blind, rapidly growing pouches. Upon the turning of the embryo, the hardly growing peripheral part of the disk becomes located in the vitelline duct. Within the head process, endodermal and notochordal cells could not be separately identified. However, slightly more posteriorly notochordal cells are seen to become embedded into the endoderm of the foregut during gastrulation. This process is not seen over the hindgut and may explain why the detachment of the notochord from the (fore)gut begins caudally.

Analysis of the dentin-pulp complex in teeth submitted to orthodontic movement in rats

PubMed Central

MASSARO, Camila da Siveira; CONSOLARO, Renata Bianco; SANTAMARIA, Milton; CONSOLARO, Maria Fernanda Martins-Ortiz; CONSOLARO, Alberto

2009-01-01

ABSTRACT In order to microscopically analyze the pulpal effects of orthodontic movement, 49 maxillary first molars of rats were submitted to orthodontic appliance composed of a closed coil spring anchored to the maxillary incisors, placed for the achievement of mesial movement. Material and Methods: Ten animals were used as the control group and were not submitted to orthodontic force; the other animals were divided into groups according to the study period of tooth movement, namely 1, 2, 3, 4, 5, 6 and 7 days. The investigation of pulp and periodontal changes included hyalinization, fibrosis, reactive dentin and vascular congestion. Statistical evaluation was performed between control and experimental groups and between periods of observation using non-parametric chi-square, Kruskal-Wallis and Dunn tests. Results: There was no statistically significant difference concerning pulpal changes between control and experimental groups nor between periods of observation. The control group, at 3 and 5 days, revealed greater hyalinization of the periodontal ligament (p<0.05), whereas root resorption was significantly greater at 5 and 7 days (p<0.05). Conclusion: No morphological change from the effect of induced tooth movement could be found in the dentin-pulp complex. In addition, no inflammatory or pulp degeneration, detectable in optical microscopy, was found in experimental groups. PMID:21499653

[Periodontal ligament regeneration using apical tooth germ cell-conditioned medium induced periodontal ligament cells sheet between dental tube and ceramic biologic bone].

PubMed

Ning, Huiying; Liu, Hongwei

2011-08-01

The purpose of this study was to establish an indirect co-culture system of rat apical tooth germ-conditioned medium (APTG-CM) and periodontal ligament cells (PDLCs). PDLCs were isolated and cultured through the method of enzyme-digestion. Vimentin and cytokeratin(CK) were used to demonstrate the cells' mesenchymal derivation. Co-culture system of APTG-CM and PDLCs for 28 days, osteocalcin (OCN), collagen type I (COL I) and bone sialoprotein (BSP) were detected in PDLCs by immunocytochemistry. Morphological changes were observed by inverted microscope. With building a transplant by dental tube, periodontal ligament cell sheet and ceramic biologic bone (CBB) in vitro, then, the combinations of dental tube and PDLCs incubated by APTG-CM were implanted subcutaneously into athymic mice for 8 weeks. This study demonstrated that cellular cementum-like tissue formed along the dentin surface and CBB, with fibrous tissue adjacent or inserted into CBB in vivo. PDLCs were grown better in the CBB than in dentin tubes. And the vertical fibers can't embed in the control. PDLCs, embedded within this APTG-CM, exhibite several phenotypic characteristics of cementoblast lineages. Thereby it contributes to the main processes of periodontal tissue regeneration with rat APTG-CM.

Neuronal activity related to spontaneous and capsaicin-induced rhythmical jaw movements in the rat.

PubMed

Ohta, M; Sasamoto, K; Kobayashi, J

1998-02-01

Intraoral capsaicin induced rhythmical jaw movements (RJM) in anesthetized rats. Neurons in the trigeminal spinal nucleus caudalis or the cortico-peduncular (CP) axons were extracellularly recorded. Capsaicin excited dose-dependently most caudalis neurons, which were activated by stimulation of the oral cavity and/or the tooth pulp and activated during spontaneous or induced RJM. Ten of 55 CP axons were antidromically activated by stimulation of the contralateral trigeminal motor nucleus. All antidromic and 29 other CP axons discharged prior to the spontaneous RJM, but most of them did not during capsaicin-induced RJM. These neuronal activities possibly initiate spontaneous RJM although the activities of caudalis neurons are necessary for capsicin-induced RJM.

Normal morphogenesis of epithelial tissues and progression of epithelial tumors

PubMed Central

Wang, Chun-Chao; Jamal, Leen; Janes, Kevin A.

2011-01-01

Epithelial cells organize into various tissue architectures that largely maintain their structure throughout the life of an organism. For decades, the morphogenesis of epithelial tissues has fascinated scientists at the interface of cell, developmental, and molecular biology. Systems biology offers ways to combine knowledge from these disciplines by building integrative models that are quantitative and predictive. Can such models be useful for gaining a deeper understanding of epithelial morphogenesis? Here, we take inventory of some recurring themes in epithelial morphogenesis that systems approaches could strive to capture. Predictive understanding of morphogenesis at the systems level would prove especially valuable for diseases such as cancer, where epithelial tissue architecture is profoundly disrupted. PMID:21898857

Species and Sex Differences in the Morphogenic Response of Primary Rodent Neurons to 3,3′-Dichlorobiphenyl (PCB 11)

PubMed Central

Sethi, Sunjay; Keil, Kimberly P.

2017-01-01

PCB 11 is an emerging global pollutant that we recently showed promotes axonal and dendritic growth in primary rat neuronal cell cultures. Here, we address the influence of sex and species on neuronal responses to PCB 11. Neuronal morphology was quantified in sex-specific primary hippocampal and cortical neuron-glia co-cultures derived from neonatal C57BL/6J mice and Sprague Dawley rats exposed for 48 h to vehicle (0.1% DMSO) or PCB 11 at concentrations ranging from 1 fM to 1 nM. Total axonal length was quantified in tau-1 immunoreactive neurons at day in vitro (DIV) 2; dendritic arborization was assessed by Sholl analysis at DIV 9 in neurons transfected with MAP2B-FusRed. In mouse cultures, PCB 11 enhanced dendritic arborization in female, but not male, hippocampal neurons and male, but not female, cortical neurons. In rat cultures, PCB 11 promoted dendritic arborization in male and female hippocampal and cortical neurons. PCB 11 also increased axonal growth in mouse and rat neurons of both sexes and neuronal cell types. These data demonstrate that PCB 11 exerts sex-specific effects on neuronal morphogenesis that vary depending on species, neurite type, and neuronal cell type. These findings have significant implications for risk assessment of this emerging developmental neurotoxicant. PMID:29295518

Species and Sex Differences in the Morphogenic Response of Primary Rodent Neurons to 3,3'-Dichlorobiphenyl (PCB 11).

PubMed

Sethi, Sunjay; Keil, Kimberly P; Lein, Pamela J

2017-12-23

PCB 11 is an emerging global pollutant that we recently showed promotes axonal and dendritic growth in primary rat neuronal cell cultures. Here, we address the influence of sex and species on neuronal responses to PCB 11. Neuronal morphology was quantified in sex-specific primary hippocampal and cortical neuron-glia co-cultures derived from neonatal C57BL/6J mice and Sprague Dawley rats exposed for 48 h to vehicle (0.1% DMSO) or PCB 11 at concentrations ranging from 1 fM to 1 nM. Total axonal length was quantified in tau-1 immunoreactive neurons at day in vitro (DIV) 2; dendritic arborization was assessed by Sholl analysis at DIV 9 in neurons transfected with MAP2B-FusRed. In mouse cultures, PCB 11 enhanced dendritic arborization in female, but not male, hippocampal neurons and male, but not female, cortical neurons. In rat cultures, PCB 11 promoted dendritic arborization in male and female hippocampal and cortical neurons. PCB 11 also increased axonal growth in mouse and rat neurons of both sexes and neuronal cell types. These data demonstrate that PCB 11 exerts sex-specific effects on neuronal morphogenesis that vary depending on species, neurite type, and neuronal cell type. These findings have significant implications for risk assessment of this emerging developmental neurotoxicant.

Targeting of Streptococcus mutans Biofilms by a Novel Small Molecule Prevents Dental Caries and Preserves the Oral Microbiome.

PubMed

Garcia, S S; Blackledge, M S; Michalek, S; Su, L; Ptacek, T; Eipers, P; Morrow, C; Lefkowitz, E J; Melander, C; Wu, H

2017-07-01

Dental caries is a costly and prevalent disease characterized by the demineralization of the tooth's enamel. Disease outcome is influenced by host factors, dietary intake, cariogenic bacteria, and other microbes. The cariogenic bacterial species Streptococcus mutans metabolizes sucrose to initiate biofilm formation on the tooth surface and consequently produces lactic acid to degrade the tooth's enamel. Persistence of S. mutans biofilms in the oral cavity can lead to tooth decay. To date, no anticaries therapies that specifically target S. mutans biofilms but do not disturb the overall oral microbiome are available. We screened a library of 2-aminoimidazole antibiofilm compounds with a biofilm dispersion assay and identified a small molecule that specifically targets S. mutans biofilms. At 5 µM, the small molecule annotated 3F1 dispersed 50% of the established S. mutans biofilm but did not disperse biofilms formed by the commensal species Streptococcus sanguinis or Streptococcus gordonii. 3F1 dispersed S. mutans biofilms independently of biofilm-related factors such as antigen I/II and glucosyltransferases. 3F1 treatment effectively prevented dental caries by controlling S. mutans in a rat caries model without perturbing the oral microbiota. Our study demonstrates that selective targeting of S. mutans biofilms by 3F1 was able to effectively reduce dental caries in vivo without affecting the overall oral microbiota shaped by the intake of dietary sugars, suggesting that the pathogenic biofilm-specific treatment is a viable strategy for disease prevention.

Tegument Protein ORF45 Plays an Essential Role in Virion Morphogenesis of Murine Gammaherpesvirus 68

PubMed Central

Jia, Xing; Shen, Sheng; Lv, Ying; Zhang, Ziwei; Guo, Haitao

2016-01-01

Tegument proteins play critical roles in herpesvirus morphogenesis. ORF45 is a conserved tegument protein of gammaherpesviruses; however, its role in virion morphogenesis is largely unknown. In this work, we determined the ultrastructural localization of murine gammaherpesvirus 68 (MHV-68) ORF45 and found that this protein was incorporated into virions around the site of host-derived vesicles. Notably, the absence of ORF45 inhibited nucleocapsid egress and blocked cytoplasmic virion maturation, demonstrating that ORF45 is essential for MHV-68 virion morphogenesis. PMID:27226376

Up-regulated ephrinB3/EphB3 expression in intractable temporal lobe epilepsy patients and pilocarpine induced experimental epilepsy rat model.

PubMed

Huang, Hao; Li, Ruohan; Yuan, Jinxian; Zhou, Xin; Liu, Xi; Ou, Shu; Xu, Tao; Chen, Yangmei

2016-05-15

EphB family receptor tyrosine kinases, in cooperation with cell surface-bound ephrinB ligands, play a critical role in maintenance of dendritic spine morphogenesis, axons guidance, synaptogenesis, synaptic reorganization and plasticity in the central nervous system (CNS). However, the expression pattern of ephrinB/EphB in intractable temporal lobe epilepsy (TLE) and the underlying molecular mechanisms during epileptogenesis remain poorly understood. Here we investigated the expression pattern and cellular distribution of ephrinB/EphB in intractable TLE patients and lithium chloride-pilocarpine induced TLE rats using real-time quantitative polymerase chain reaction (RT-qPCR), immunohistochemistry, double-labeled immunofluorescence and Western blot analysis. Compared to control groups, ephrinB3 and EphB3 mRNA expression were significantly up-regulated in intractable TLE patients and TLE rats, while the mRNA expression trend of ephrinB1/2 and EphB1/2/4/6 in intractable TLE patients and TLE rats were inconsistent. Western blot analysis and semi-quantitative immunohistochemistry confirmed that ephrinB3 and EphB3 protein level were up-regulated in intractable TLE patients and TLE rats. At the same time, double-labeled immunofluorescence indicate that ephrinB3 was expressed mainly in the cytoplasm and protrusions of glia and neurons, while EphB3 was expressed mainly in the cytoplasm of neurons. Taken together, up-regulated expression of ephrinB3/EphB3 in intractable TLE patients and experimental TLE rats suggested that ephrinB3/EphB3 might be involved in the pathogenesis of TLE. Copyright © 2016 Elsevier B.V. All rights reserved.

Nicotine effect on bone remodeling during orthodontic tooth movement: Histological study in rats

PubMed Central

Shintcovsk, Ricardo Lima; Knop, Luégya; Tanaka, Orlando Motohiro; Maruo, Hiroshi

2014-01-01

Introduction Nicotine is harmful to angiogenesis, osteogenesis and synthesis of collagen. Objective The aim of this study was to investigate the effect of nicotine on bone remodeling during orthodontic movement in rats. Methods Eighty male Wistar rats were randomly divided into three groups: Group C (control), group CM (with orthodontic movement) and group NM (nicotine with orthodontic movement) groups. The animals comprising groups C and CM received 0.9% saline solution while group NM received nicotine solution (2 mg/kg). A nickel-titanium closed-coil spring was used to induce tooth movement. The animals were euthanized and tissue specimens were processed histologically. We quantified blood vessels, Howship's lacunae and osteoclast-like cells present in the tension and compression areas of periodontal ligaments. The extent of bone formation was evaluated under polarized light to determine the percentage of immature/mature collagen. Results We observed lower blood vessel densities in the NM group in comparison to the CM group, three (p < 0.001) and seven (p < 0.05) days after force application. Osteoclast-like cells and Howship's lacunae in the NM group presented lower levels of expression in comparison to the CM group, with significant differences on day 7 (p < 0.05 for both variables) and day 14 (p < 0.05 for osteoclast-like cells and p < 0.01 for Howship's lacunae). The percentage of immature collagen increased in the NM group in comparison to the CM group with a statistically significant difference on day 3 (p < 0.05), day 7 (p < 0.001), day 14 (p < 0.001) and day 21 (p < 0.001). Conclusions Nicotine affects bone remodeling during orthodontic movement, reducing angiogenesis, osteoclast-like cells and Howship's lacunae, thereby delaying the collagen maturation process in developed bone matrix. PMID:24945520

DELAYED TOOTH REPLANTATION AFTER ROOT SURFACE TREATMENT WITH SODIUM HYPOCHLORITE AND SODIUM FLUORIDE: HISTOMORPHOMETRIC ANALYSIS IN RATS

PubMed Central

Sottovia, André Dotto; Sonoda, Celso Koogi; Poi, Wilson Roberto; Panzarini, Sônia Regina; Lauris, José Roberto Pereira

2006-01-01

In cases of delayed tooth replantation, non-vital periodontal ligament remnants have been removed with sodium hypochlorite in an attempt to control root resorption. Nevertheless, reports of its irritating potential in contact with the alveolar connective tissue have been described. Therefore, this study evaluated the healing process on delayed replantation of rat teeth, after periodontal ligament removal by different treatment modalities. Twenty-four rats, assigned to 3 groups (n=8), had their upper right incisor extracted and left on the workbench for desiccation during 60 min. Afterwards, the teeth in group I were immersed in saline for 2 min. In group II, root surfaces were scrubbed with gauze soaked in saline for 2 min; and in group III, scrubbing was done with gauze soaked in 1% sodium hypochlorite solution. Thereafter, root surfaces were etched with 37% phosphoric acid and immersed in 2% acidulate-phosphate sodium fluoride solution, at pH 5.5. Root canals were filled with a calcium hydroxide-based paste and the teeth were replanted. The animals were sacrificed 60 days postoperatively and the pieces containing the replanted teeth were processed and paraffin-embedded. Semi-serial transversally sections were obtained from the middle third of the root and stained with hematoxylin and eosin for histomorphometric analysis. Data were analyzed statistically using Kruskal-Wallis and Dunn's tests. The results showed that root structure and cementum extension were more affected by resorption in group III (p<0.05). All groups were affected by root resorption but the treatment performed in group III was the least effective for its control. The treatment accomplished in groups I and II yielded similar results to each other. PMID:19089038

Delayed tooth replantation after root surface treatment with sodium hypochlorite and sodium fluoride: histomorphometric analysis in rats.

PubMed

Sottovia, André Dotto; Sonoda, Celso Koogi; Poi, Wilson Roberto; Panzarini, Sônia Regina; Lauris, José Roberto Pereira

2006-04-01

In cases of delayed tooth replantation, non-vital periodontal ligament remnants have been removed with sodium hypochlorite in an attempt to control root resorption. Nevertheless, reports of its irritating potential in contact with the alveolar connective tissue have been described. Therefore, this study evaluated the healing process on delayed replantation of rat teeth, after periodontal ligament removal by different treatment modalities. Twenty-four rats, assigned to 3 groups (n=8), had their upper right incisor extracted and left on the workbench for desiccation during 60 min. Afterwards, the teeth in group I were immersed in saline for 2 min. In group II, root surfaces were scrubbed with gauze soaked in saline for 2 min; and in group III, scrubbing was done with gauze soaked in 1% sodium hypochlorite solution. Thereafter, root surfaces were etched with 37% phosphoric acid and immersed in 2% acidulate-phosphate sodium fluoride solution, at pH 5.5. Root canals were filled with a calcium hydroxide-based paste and the teeth were replanted. The animals were sacrificed 60 days postoperatively and the pieces containing the replanted teeth were processed and paraffin- embedded. Semi-serial transversally sections were obtained from the middle third of the root and stained with hematoxylin and eosin for histomorphometric analysis. Data were analyzed statistically using Kruskal-Wallis and Dunn's tests. The results showed that root structure and cementum extension were more affected by resorption in group III (p<0.05). All groups were affected by root resorption but the treatment performed in group III was the least effective for its control. The treatment accomplished in groups I and II yielded similar results to each other.

Effect of local injection of Zolena, zoledronic acid made in Iran, on orthodontic tooth movement and root and bone resorption in rats.

PubMed

Seifi, Massoud; Asefi, Sohrab; Hatamifard, Ghazal; Lotfi, Ali

2017-01-01

Background. Anchorage control is an essential part of orthodontic treatment planning, especially in adult patients who demand a more convenient treatment. Zoledronic acid (ZA) is an effective choice to address this problem. It is the most potent member of the bisphosphonates family that has an inhibitory effect on bone resorption by suppressing osteoclast function. Therefore, ZA might be a good option for orthodontic anchorage control. The current study evaluated the effect of local administration of Zolena (ZA made in Iran) on orthodontic tooth movement (OTM) and root and bone resorption. Methods. The experimental group consisted of 30 rats in 3 subgroups (n=10). Anesthesia was induced, and one closed NiTi coil spring was installed between the first molar and central incisor unilaterally, except for the negative control group. The positive control group received vestibular injection of 0.01 mL of saline next to the maxillary first molar, and 0.01 mL of the solution was injected at the same site in the ZA group. After 21 days, the rats were sacrificed and the distance between the first and second molars was measured with a leaf gauge. Histological analysis was conducted by a blind pathologist for the number of Howship's lacunae, blood vessels, osteoclast-like cells and root resorption lacunae. Data were analyzed with ANOVA, Tukey test and t-test. Results. There were no significant differences in OTM between the force-applied groups. ZA significantly inhibited bone/root resorption and angiogenesis compared to the positive control group. Conclusion. Zolena did not decrease OTM but significantly inhibited bone and root resorption. Zolena might be less potent than its foreign counterparts.

Fibronectin regulates calvarial osteoblast differentiation

NASA Technical Reports Server (NTRS)

Moursi, A. M.; Damsky, C. H.; Lull, J.; Zimmerman, D.; Doty, S. B.; Aota, S.; Globus, R. K.

1996-01-01

The secretion of fibronectin by differentiating osteoblasts and its accumulation at sites of osteogenesis suggest that fibronectin participates in bone formation. To test this directly, we determined whether fibronectin-cell interactions regulate progressive differentiation of cultured fetal rat calvarial osteoblasts. Spatial distributions of alpha 5 integrin subunit, fibronectin, osteopontin (bone sialoprotein I) and osteocalcin (bone Gla-protein) were similar in fetal rat calvaria and mineralized, bone-like nodules formed by cultured osteoblasts. Addition of anti-fibronectin antibodies to cultures at confluence reduced subsequent formation of nodules to less than 10% of control values, showing that fibronectin is required for normal nodule morphogenesis. Anti-fibronectin antibodies selectively inhibited steady-state expression of mRNA for genes associated with osteoblast differentiation; mRNA levels for alkaline phosphatase and osteocalcin were suppressed, whereas fibronectin, type I collagen and osteopontin were unaffected. To identify functionally relevant domains of fibronectin, we treated cells with soluble fibronectin fragments and peptides. Cell-binding fibronectin fragments (type III repeats 6-10) containing the Arg-Gly-Asp (RGD) sequence blocked both nodule initiation and maturation, whether or not they contained a functional synergy site. In contrast, addition of the RGD-containing peptide GRGDSPK alone did not inhibit nodule initiation, although it did block nodule maturation. Thus, in addition to the RGD sequence, other features of the large cell-binding fragments contribute to the full osteogenic effects of fibronectin. Nodule formation and osteoblast differentiation resumed after anti-fibronectin antibodies or GRGDSPK peptides were omitted from the media, showing that the inhibition was reversible and the treatments were not cytotoxic. Outside the central cell-binding domain, peptides from the IIICS region and antibodies to the N terminus did not inhibit nodule formation. We conclude that osteoblasts interact with the central cell-binding domain of endogenously produced fibronectin during early stages of differentiation, and that these interactions regulate both normal morphogenesis and gene expression.

Decreased Expression of Integrin Subunits α3, α6, and α8 in the Branching Airway Mesenchyme of Nitrofen-Induced Hypoplastic Lungs.

PubMed

Takahashi, Toshiaki; Friedmacher, Florian; Zimmer, Julia; Puri, Prem

2018-02-01

 Pulmonary hypoplasia (PH), characterized by smaller lung size and reduced airway branching, remains a major cause of neonatal mortality in newborns with congenital diaphragmatic hernia (CDH). Integrin-mediated cell-matrix interactions play an essential role in the fetal lung mesenchyme by stimulating branching morphogenesis. Mice lacking integrin subunits α3 (Itga3) and α6 (Itga6) exhibit severe PH. Furthermore, Itga8-knockout mice show defective airway branching, suggesting that Itga3, Itga6, and Itga8 are crucial for fetal lung development. We hypothesized that expression of Itga3, Itga6, and Itga8 is decreased in the branching airway mesenchyme of hypoplastic rat lungs in the nitrofen-induced CDH model.  Time-mated rats received nitrofen or vehicle on gestational day 9 (D9). Fetuses were sacrificed on D15, D18, and D21, and dissected lungs were divided into control and nitrofen-exposed specimens ( n  = 12 per time-point and group, respectively). Pulmonary gene expression of Itga3, Itga6, and Itga8 was analyzed by quantitative real-time polymerase chain reaction. Immunofluorescence double-staining for Itga3, Itga6, and Itga8 was combined with the mesenchymal marker Fgf10 to evaluate protein expression and localization in branching airway tissue.  Relative mRNA expression of Itga3, Itga6, and Itga8 was significantly decreased in lungs of nitrofen-exposed fetuses on D15, D18, and D21 compared with controls. Confocal laser scanning microscopy showed markedly diminished immunofluorescence of Itga3, Itga6, and Itga8 mainly in mesenchymal cells surrounding branching airways of nitrofen-exposed fetuses on D15, D18, and D21 compared with controls.  Decreased expression of Itga3, Itga6, and Itga8 in the pulmonary mesenchyme may lead to disruptions in airway branching morphogenesis, thus contributing to PH in the nitrofen-induced CDH model. Georg Thieme Verlag KG Stuttgart · New York.

Effect of LED-mediated-photobiomodulation therapy on orthodontic tooth movement and root resorption in rats.

PubMed

Ekizer, Abdullah; Uysal, Tancan; Güray, Enis; Akkuş, Derya

2015-02-01

The aim of this experimental study was to evaluate the effects of light-emitting diode-mediated-photobiomodulation therapy (LPT), on the rate of orthodontic tooth movement (TM) and orthodontically induced root resorption, in rats. Twenty male 12-week-old Wistar rats were separated into two groups (control and LPT) and 50 cN of force was applied between maxillary left molar and incisor with a coil spring. In the treatment group, LPT was applied with an energy density of 20 mW/cm(2) over a period of 10 consecutive days directly over the movement of the first molar teeth area. The distance between the teeth was measured with a digital caliper on days 0 (T0), 10 (T1), and 21 (T2) on dental cast models. The surface area of root resorption lacunae was measured histomorphometrically using digital photomicrographs. Mann-Whitney U and Wilcoxon tests were used for statistical evaluation at p < 0.05 level. TM during two different time intervals (T1-T0 and T2-T1) were compared for both groups and a statistically significant difference was found in the LPT group (p = 0.016). The TM amount at the first time period (1.31 ± 0.36 mm) was significantly higher than the second time period (0.24 ± 0.23 mm) in the LPT group. Statistical analysis showed significant differences between two groups after treatment/observation period (p = 0.017). The magnitude of movement in the treatment group was higher (1.55 ± 0.33 mm) compared to the control group (1.06 ± 0.35 mm). Histomorphometric analysis of root resorption, expressed as a percentage, showed that the average relative root resorption affecting the maxillary molars on the TM side was 0.098 ± 0.066 in the LPT group and 0.494 ± 0.224 in the control group. Statistically significant inhibition of root resorption with LPT was determined (p < 0.001) on the TM side. The LPT method has the potential of accelerating orthodontic tooth movement and inhibitory effects on orthodontically induced resorptive activity.

[Effect of overdose fluoride on expression of bone sialoprotein in developing dental tissues of rats].

PubMed

Xu, Zhi-ling; Wang, Qiang; Liu, Tian-lin; Guo, Li-ying; Jing, Feng-qiu; Liu, Hui

2006-04-01

To investigate the changes of bone sialoprotein (BSP) in developing dental tissues of rats exposed to fluoride. Twenty rats were randomly divided into two groups, one was with distilled water (control group), the other was with distilled water treated by fluoride (experimental group). When the fluorosis model was established, the changes of the expression of BSP were investigated and compared between the two groups. HE staining was used to observe the morphology of the cell, and immunohistochemisty assay was used to determine the expression of BSP in rat incisor. Student's t test was used for statistical analysis. The ameloblasts had normal morphology and arranged orderly. Immunoreactivitis of BSP was present in matured ameloblasts, dentinoblasts, cementoblasts, and the matrix in the control group. But in the experimental group the ameloblasts arranged in multiple layers, the enamel matrix was confused and the expression of BSP was significantly lower than that of the control group. Statistical analysis showed significant differences between the two groups (P<0.01). Fluoride can inhibit the expression of BSP in developing dental tissues of rats, and then inhibit differentiation of the tooth epithelial cells and secretion of matrix. This is a probable intracellular mechanism of dental fluorosis.

The role of the BMP signaling cascade in regulation of stem cell activity following massive small bowel resection in a rat.

PubMed

Sukhotnik, I; Berkowitz, D; Dorfman, T; Halabi, Salim; Pollak, Y; Bejar, J; Bitterman, A; Coran, A G

2016-02-01

Bone morphogenetic proteins (BMPs) are a group of growth factors that are implicated in intestinal growth, morphogenesis, differentiation, and homeostasis. The role of the BMP signaling cascade in stimulation of cell proliferation after massive small bowel resection is unknown. The purpose of this study was to evaluate the role of BMP signaling during intestinal adaptation in a rat model of short bowel syndrome (SBS). Male rats were divided into two groups: Sham rats underwent bowel transection and SBS rats underwent a 75 % bowel resection. Parameters of intestinal adaptation, enterocyte proliferation and apoptosis were determined 2 weeks after operation. Illumina's Digital Gene Expression analysis was used to determine the BMP signaling gene expression profiling. BMP-related genes and protein expression were determined using real-time PCR, Western blotting and immunohistochemistry. From the total number of 20,000 probes, 8 genes related to BMP signaling were investigated. From these genes, five genes were found to be up-regulated in jejunum (BMP1-10 %, BMP2-twofold increase, BMP3-10 %, BMP2R-12 % and STAT3-28 %) and four genes to be up-regulated in ileum (BMP1-16 %, BMP2-27 %, BMP3-10 %, and STAT3-20 %) in SBS vs sham animals with a relative change in gene expression level of 10 % or more. SBS rats also demonstrated a significant increase in BMP2 and STAT3 mRNA and protein levels (determined by real-time PCR and Western blot) compared to control animals. Two weeks following massive bowel resection in rats, the BMP signaling pathway is stimulated. BMP signaling may serve as an important mediator of reciprocal interactions between the epithelium and the underlying mesenchymal stroma during intestinal adaptation following massive bowel resection in a rat.

The Pea Seedling as a Model of Normal and Abnormal Morphogenesis

ERIC Educational Resources Information Center

Kurkdjian, Armen; And Others

1974-01-01

Describes several simple and inexpensive experiments designed to facilitate the study of normal and abnormal morphogenesis in the biology laboratory. Seedlings of the common garden pea are used in the experiments, and abnormal morphogenesis (tumors) are induced by a virulent strain of the crown-gall organism, Agrobacterium tumefaciens. (JR)

MT2-MMP-dependent release of collagen IV NC1 domains regulates submandibular gland branching morphogenesis.

PubMed

Rebustini, Ivan T; Myers, Christopher; Lassiter, Keyonica S; Surmak, Andrew; Szabova, Ludmila; Holmbeck, Kenn; Pedchenko, Vadim; Hudson, Billy G; Hoffman, Matthew P

2009-10-01

Proteolysis is essential during branching morphogenesis, but the roles of MT-MMPs and their proteolytic products are not clearly understood. Here, we discover that decreasing MT-MMP activity during submandibular gland branching morphogenesis decreases proliferation and increases collagen IV and MT-MMP expression. Specifically, reducing epithelial MT2-MMP profoundly decreases proliferation and morphogenesis, increases Col4a2 and intracellular accumulation of collagen IV, and decreases the proteolytic release of collagen IV NC1 domains. Importantly, we demonstrate the presence of collagen IV NC1 domains in developing tissue. Furthermore, recombinant collagen IV NC1 domains rescue branching morphogenesis after MT2-siRNA treatment, increasing MT-MMP and proproliferative gene expression via beta1 integrin and PI3K-AKT signaling. Additionally, HBEGF also rescues MT2-siRNA treatment, increasing NC1 domain release, proliferation, and MT2-MMP and Hbegf expression. Our studies provide mechanistic insight into how MT2-MMP-dependent release of bioactive NC1 domains from collagen IV is critical for integrating collagen IV synthesis and proteolysis with epithelial proliferation during branching morphogenesis.

Developmental expression of Hsp90, Hsp70 and HSF during morphogenesis in the vetigastropod Haliotis asinina.

PubMed

Gunter, Helen M; Degnan, Bernard M

2007-08-01

Heat shock proteins (Hsps) have dual functions, participating in both the stress response and a broad range of developmental processes. At physiological temperatures, it has been demonstrated in deuterostomes (vertebrates) and ecdysozoans (insects) that Hsps are expressed in tissues that are undergoing differentiation and morphogenesis. Here we investigate the developmental expression of Hsp70, Hsp90 and their regulatory transcription factor heat shock transcription factor (HSF) in the marine gastropod Haliotis asinina, a representative of the 3rd major lineage of bilaterian animals, the Lophotrochozoa. HasHsp70, HasHsp90 and HasHSF are maternally expressed in H. asinina and are progressively restricted to the micromere lineage during cleavage. During larval morphogenesis, they are expressed in unique and overlapping patterns in the prototroch, foot, and mantle. Hsp expression peaked in these tissues during periods of cell differentiation and morphogenesis, returning to lower levels after morphogenesis was complete. These patterns of Hsp and HSF expression in H. asinina are akin to those observed in ecdysozoans and deuterostomes, with Hsps being activated in cells and tissues undergoing morphogenesis.

Multiscale biomechanical responses of adapted bone-periodontal ligament-tooth fibrous joints

PubMed Central

Jang, Andrew T.; Merkle, Arno; Fahey, Kevin; Gansky, Stuart A.; Ho, Sunita P.

2015-01-01

Reduced functional loads cause adaptations in organs. In this study, temporal adaptations of bone-ligament-tooth fibrous joints to reduced functional loads were mapped using a holistic approach. Systematic studies were performed to evaluate organ-level and tissue-level adaptations in specimens harvested periodically from rats given powder food for 6 months (N = 60 over 8,12,16,20, and 24 weeks). Bone-periodontal ligament (PDL)-tooth fibrous joint adaptation was evaluated by comparing changes in joint stiffness with changes in functional space between the tooth and alveolar bony socket. Adaptations in tissues included mapping changes in the PDL and bone architecture as observed from collagen birefringence, bone hardness and volume fraction in rats fed soft foods (soft diet, SD) compared to those fed hard pellets as a routine diet (hard diet, HD). In situ biomechanical testing on harvested fibrous joints revealed increased stiffness in SD groups (SD:239-605 N/mm) (p<0.05) at 8 and 12 weeks. Increased joint stiffness in early development phase was due to decreased functional space (at 8wks change in functional space was −33 µm, at 12wks change in functional space was −30 µm) and shifts in tissue quality as highlighted by birefringence, architecture and hardness. These physical changes were not observed in joints that were well into function, that is, in rodents older than 12 weeks of age. Significant adaptations in older groups were highlighted by shifts in bone growth (bone volume fraction 24wks: Δ-0.06) and bone hardness (8wks: Δ−0.04 GPa, 16 wks: Δ−0.07 GPa, 24wks: Δ−0.06 GPa). The response rate (N/s) of joints to mechanical loads decreased in SD groups. Results from the study showed that joint adaptation depended on age. The initial form-related adaptation (observed change in functional space) can challenge strain-adaptive nature of tissues to meet functional demands with increasing age into adulthood. The coupled effect between functional space in the bone-PDLtooth complex and strain-adaptive nature of tissues is necessary to accommodate functional demands, and is temporally sensitive despite joint malfunction. From an applied science perspective, we propose that adaptations are registered as functional history in tissues and joints. PMID:26151121

The case for applying tissue engineering methodologies to instruct human organoid morphogenesis.

PubMed

Marti-Figueroa, Carlos R; Ashton, Randolph S

2017-05-01

Three-dimensional organoids derived from human pluripotent stem cell (hPSC) derivatives have become widely used in vitro models for studying development and disease. Their ability to recapitulate facets of normal human development during in vitro morphogenesis produces tissue structures with unprecedented biomimicry. Current organoid derivation protocols primarily rely on spontaneous morphogenesis processes to occur within 3-D spherical cell aggregates with minimal to no exogenous control. This yields organoids containing microscale regions of biomimetic tissues, but at the macroscale (i.e. 100's of microns to millimeters), the organoids' morphology, cytoarchitecture, and cellular composition are non-biomimetic and variable. The current lack of control over in vitro organoid morphogenesis at the microscale induces aberrations at the macroscale, which impedes realization of the technology's potential to reproducibly form anatomically correct human tissue units that could serve as optimal human in vitro models and even transplants. Here, we review tissue engineering methodologies that could be used to develop powerful approaches for instructing multiscale, 3-D human organoid morphogenesis. Such technological mergers are critically needed to harness organoid morphogenesis as a tool for engineering functional human tissues with biomimetic anatomy and physiology. Human PSC-derived 3-D organoids are revolutionizing the biomedical sciences. They enable the study of development and disease within patient-specific genetic backgrounds and unprecedented biomimetic tissue microenvironments. However, their uncontrolled, spontaneous morphogenesis at the microscale yields inconsistences in macroscale organoid morphology, cytoarchitecture, and cellular composition that limits their standardization and application. Integration of tissue engineering methods with organoid derivation protocols could allow us to harness their potential by instructing standardized in vitro morphogenesis to generate organoids with biomimicry at all scales. Such advancements would enable the use of organoids as a basis for 'next-generation' tissue engineering of functional, anatomically mimetic human tissues and potentially novel organ transplants. Here, we discuss critical aspects of organoid morphogenesis where application of innovative tissue engineering methodologies would yield significant advancement towards this goal. Copyright © 2017. Published by Elsevier Ltd.

Expression of EMAP-II in the rat dental follicle and its potential role in tooth eruption

PubMed Central

Liu, Dawen; Wise, Gary E.

2008-01-01

Endothelial monocyte-activating polypeptide II (EMAP-II) is an inflammatory cytokine with chemotactic activity. Because the dental follicle (DF) recruits mononuclear cells (osteoclast precursors) to promote the osteoclastogenesis needed for tooth eruption, it was the aim of this study to determine if EMAP-II may contribute to this recruitment. Using a DNA microarray, EMAP-II was found to be highly expressed in vivo in the DFs of day 1 to day 11 postnatal rats, with its expression elevated at days 1 and 3. Using a siRNA to knock down EMAP-II expression also resulted in a reduction in expression of CSF-1 and MCP-1 in the DF cells. Addition of EMAP-II protein to the DF cells partially restored the expression of CSF-1 and MCP-1. In chemotaxis assays using either conditioned medium of the DF cells with anti-EMAP-II antibody added or conditioned medium of DF cells with EMAP-II knocked down by siRNA, migration indexes of bone marrow mononuclear cells were significantly reduced. These results suggest that EMAP-II is another chemotactic molecule in the dental follicle involved in recruitment of mononuclear cells, and that EMAP-II may exert its chemotactic function directly by recruiting mononuclear cells and indirectly by enhancing the expression of other chemotactic molecules (CSF-1 and MCP-1). PMID:18705801

Postnatal epithelium and mesenchyme stem/progenitor cells in bioengineered amelogenesis and dentinogenesis.

PubMed

Jiang, Nan; Zhou, Jian; Chen, Mo; Schiff, Michael D; Lee, Chang H; Kong, Kimi; Embree, Mildred C; Zhou, Yanheng; Mao, Jeremy J

2014-02-01

Rodent incisors provide a classic model for studying epithelial-mesenchymal interactions in development. However, postnatal stem/progenitor cells in rodent incisors have not been exploited for tooth regeneration. Here, we characterized postnatal rat incisor epithelium and mesenchyme stem/progenitor cells and found that they formed enamel- and dentin-like tissues in vivo. Epithelium and mesenchyme cells were harvested separately from the apical region of postnatal 4-5 day rat incisors. Epithelial and mesenchymal phenotypes were confirmed by immunocytochemistry, CFU assay and/or multi-lineage differentiation. CK14+, Sox2+ and Lgr5+ epithelium stem cells from the cervical loop enhanced amelogenin and ameloblastin expression upon BMP4 or FGF3 stimulation, signifying their differentiation towards ameloblast-like cells, whereas mesenchyme stem/progenitor cells upon BMP4, BMP7 and Wnt3a treatment robustly expressed Dspp, a hallmark of odontoblastic differentiation. We then control-released microencapsulated BMP4, BMP7 and Wnt3a in transplants of epithelium and mesenchyme stem/progenitor cells in the renal capsule of athymic mice in vivo. Enamel and dentin-like tissues were generated in two integrated layers with specific expression of amelogenin and ameloblastin in the newly formed, de novo enamel-like tissue, and DSP in dentin-like tissue. These findings suggest that postnatal epithelium and mesenchyme stem/progenitor cells can be primed towards bioengineered tooth regeneration. Copyright © 2013 Elsevier Ltd. All rights reserved.

Comparison of Gingiva, Dental Pulp, and Periodontal Ligament Cells From the Standpoint of Mesenchymal Stem Cell Properties.

PubMed

Otabe, Koji; Muneta, Takeshi; Kawashima, Nobuyuki; Suda, Hideaki; Tsuji, Kunikazu; Sekiya, Ichiro

2012-01-01

The specific properties of mesenchymal stem cells (MSCs) in oral tissues still remain unknown though their existence has been previously reported. We collected gingiva, dental pulp, and periodontal ligament tissues from removed teeth and isolated MSCs. These MSCs were compared in terms of their yields per tooth, surface epitopes, and differentiation potentials by patient-matched analysis. For in vivo calcification analysis, rat gingival and dental pulp cells mounted on β-tricalcium phospateTCP were transplanted into the perivertebral muscle of rats for 6 weeks. Gingival cells and dental pulp cells showed higher yield per tooth than periodontal ligament cells (n=6, p<0.05). Yields of periodontal ligament cells were too low for further analysis. Gingival and dental pulp cells expressed MSC markers such as CD44, CD90, and CD166. Gingival and dental pulp cells obtained phenotypes of chondrocytes and adipocytes in vitro. Approximately 60% of the colonies of gingival cells and 40% of the colonies of dental pulp cells were positively stained with alizarin red in vitro, and both gingival and dental pulp cells were calcified in vivo. We clarified properties of MSCs derived from removed teeth. We could obtain a high yield of MSCs with osteogenic potential from gingiva and dental pulp. These results indicate that gingiva and dental pulp are putative cell sources for hard tissue regeneration.

Comparison of Gingiva, Dental Pulp, and Periodontal Ligament Cells From the Standpoint of Mesenchymal Stem Cell Properties

PubMed Central

Otabe, Koji; Muneta, Takeshi; Kawashima, Nobuyuki; Suda, Hideaki; Tsuji, Kunikazu; Sekiya, Ichiro

2012-01-01

The specific properties of mesenchymal stem cells (MSCs) in oral tissues still remain unknown though their existence has been previously reported. We collected gingiva, dental pulp, and periodontal ligament tissues from removed teeth and isolated MSCs. These MSCs were compared in terms of their yields per tooth, surface epitopes, and differentiation potentials by patient-matched analysis. For in vivo calcification analysis, rat gingival and dental pulp cells mounted on β-tricalcium phospateTCP were transplanted into the perivertebral muscle of rats for 6 weeks. Gingival cells and dental pulp cells showed higher yield per tooth than periodontal ligament cells (n=6, p<0.05). Yields of periodontal ligament cells were too low for further analysis. Gingival and dental pulp cells expressed MSC markers such as CD44, CD90, and CD166. Gingival and dental pulp cells obtained phenotypes of chondrocytes and adipocytes in vitro. Approximately 60% of the colonies of gingival cells and 40% of the colonies of dental pulp cells were positively stained with alizarin red in vitro, and both gingival and dental pulp cells were calcified in vivo. We clarified properties of MSCs derived from removed teeth. We could obtain a high yield of MSCs with osteogenic potential from gingiva and dental pulp. These results indicate that gingiva and dental pulp are putative cell sources for hard tissue regeneration. PMID:26858852

Expression of transcripts for fibroblast growth factor 18 and its possible receptors during postnatal dentin formation in rat molars.

PubMed

Baba, Otto; Ota, Masato S; Terashima, Tatsuo; Tabata, Makoto J; Takano, Yoshiro

2015-05-01

Fibroblast growth factors (FGFs) regulate the proliferation and differentiation of various cells via their respective receptors (FGFRs). During the early stages of tooth development in fetal mice, FGFs and FGFRs have been shown to be expressed in dental epithelia and mesenchymal cells at the initial stages of odontogenesis and to regulate cell proliferation and differentiation. However, little is known about the expression patterns of FGFs in the advanced stages of tooth development. In the present study, we focused on FGF18 expression in the rat mandibular first molar (M1) during the postnatal crown and root formation stages. FGF18 signals by RT-PCR using cDNAs from M1 were very weak at postnatal day 5 and were significantly up-regulated at days 7, 9 and 15. Transcripts were undetectable by in situ hybridization (ISH) but could be detected by in situ RT-PCR in the differentiated odontoblasts and cells of the sub-odontoblastic layer in both crown and root portions of M1 at day 15. The transcripts of FGFR2c and FGFR3, possible candidate receptors of FGF18, were detected by RT-PCR and ISH in differentiated odontoblasts throughout postnatal development. These results suggest the continual involvement of FGF18 signaling in the regulation of odontoblasts during root formation where it may contribute to dentin matrix formation and/or mineralization.

High-frequency pulsed low-level diode laser therapy accelerates wound healing of tooth extraction socket: An in vivo study.

PubMed

Noda, Masahiro; Aoki, Akira; Mizutani, Koji; Lin, Taichen; Komaki, Motohiro; Shibata, Shunichi; Izumi, Yuichi

2016-12-01

This study aimed to evaluate the effects of high-frequency pulsed (HiFP) low-level laser therapy (LLLT) on early wound healing of tooth extraction sockets in rats. Bilateral maxillary first molars were extracted from 6-week-old Sprague-Dawley rats. Sockets on the right were treated by HiFP low-level diode laser irradiation (904-910 nm); the left sides served as unirradiated controls. LLLT (0.28 W, 30 kHz, 200-ns pulse, 0.6% duty cycle, 61.2 J/cm 2 total power density) was employed immediately after extraction and every 24 hours thereafter. The maxillae including the sockets were resected 3 or 7 days after extraction. Soft-tissue healing was evaluated on days 0, 3, and 7. The bone mineral content (BMC), bone volume (BV), and bone mineral density (BMD) of the extraction sockets were evaluated by microcomputed tomography, and histomorphometric analysis was carried out on day 7. Real-time PCR analysis of osteogenic marker expression and immunohistochemical detection of proliferating cell nuclear antigen (PCNA)-positive cells were performed on day 3. Compared with control sites, the un-epithelialized areas of the extracted sites were significantly reduced by irradiation (P = 0.04), and the BMC, BV, and BMD of laser-treated sites were significantly increased (P = 0.004, 0.006, and 0.009, respectively). On day 7, the mean height of newly formed immature woven bone was higher in laser-treated sites (P = 0.24). On day 3, laser-treated sites showed significantly higher osteocalcin mRNA expression (P = 0.04) and PCNA-positive cell numbers (P = 0.01). HiFP low-level diode laser irradiation enhanced soft- and hard-tissue healing of tooth extraction sockets. Lasers Surg. Med. 48:955-964, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Graphene oxide scaffold accelerates cellular proliferative response and alveolar bone healing of tooth extraction socket.

PubMed

Nishida, Erika; Miyaji, Hirofumi; Kato, Akihito; Takita, Hiroko; Iwanaga, Toshihiko; Momose, Takehito; Ogawa, Kosuke; Murakami, Shusuke; Sugaya, Tsutomu; Kawanami, Masamitsu

2016-01-01

Graphene oxide (GO) consisting of a carbon monolayer has been widely investigated for tissue engineering platforms because of its unique properties. For this study, we fabricated a GO-applied scaffold and assessed the cellular and tissue behaviors in the scaffold. A preclinical test was conducted to ascertain whether the GO scaffold promoted bone induction in dog tooth extraction sockets. For this study, GO scaffolds were prepared by coating the surface of a collagen sponge scaffold with 0.1 and 1 µg/mL GO dispersion. Scaffolds were characterized using scanning electron microscopy (SEM), physical testing, cell seeding, and rat subcutaneous implant testing. Then a GO scaffold was implanted into a dog tooth extraction socket. Histological observations were made at 2 weeks postsurgery. SEM observations show that GO attached to the surface of collagen scaffold struts. The GO scaffold exhibited an interconnected structure resembling that of control subjects. GO application improved the physical strength, enzyme resistance, and adsorption of calcium and proteins. Cytocompatibility tests showed that GO application significantly increased osteoblastic MC3T3-E1 cell proliferation. In addition, an assessment of rat subcutaneous tissue response revealed that implantation of 1 µg/mL GO scaffold stimulated cellular ingrowth behavior, suggesting that the GO scaffold exhibited good biocompatibility. The tissue ingrowth area and DNA contents of 1 µg/mL GO scaffold were, respectively, approximately 2.5-fold and 1.4-fold greater than those of the control. Particularly, the infiltration of ED2-positive (M2) macrophages and blood vessels were prominent in the GO scaffold. Dog bone-formation tests showed that 1 µg/mL GO scaffold implantation enhanced bone formation. New bone formation following GO scaffold implantation was enhanced fivefold compared to that in control subjects. These results suggest that GO was biocompatible and had high bone-formation capability for the scaffold. The GO scaffold is expected to be beneficial for bone tissue engineering therapy.

Expression of Iroquois genes is up-regulated during early lung development in the nitrofen-induced pulmonary hypoplasia.

PubMed

Doi, Takashi; Lukošiūtė, Aušra; Ruttenstock, Elke; Dingemann, Jens; Puri, Prem

2011-01-01

Iroquois homeobox (Irx) genes have been implicated in the early lung morphogenesis of vertebrates. Irx1-3 and Irx5 gene expression is seen in fetal lung in rodents up to day (D) 18.5 of gestation. Fetal lung in Irx knockdown mice shows loss of mesenchyme and dilated airspaces, whereas nitrofen-induced hypoplastic lung displays thickened mesenchyme and diminished airspaces. We hypothesized that the Irx genes are up-regulated during early lung morphogenesis in the nitrofen-induced hypoplastic lung. Pregnant rats were exposed either to olive oil or nitrofen on D9. Fetal lungs harvested on D15 were divided into control and nitrofen groups; and the lungs harvested on D18 were divided into control, nitrofen without congenital diaphragmatic hernia (CDH[-]), and nitrofen with CDH (CDH[+]). Irx gene expression levels were analyzed by reverse transcriptase polymerase chain reaction. Immunohistochemistry was performed to evaluate protein expression of Irx family. Pulmonary Irx1-3 and Irx5 messenger RNA expression levels were significantly up-regulated in nitrofen group compared with controls at D15. On D15, Irx immunoreactivity was increased in nitrofen-induced hypoplastic lung compared with controls. Overexpression of Irx genes in the early lung development may cause pulmonary hypoplasia in the nitrofen CDH model by inducing lung dysmorphogenesis with thickened mesenchyme and diminished airspaces. Copyright © 2011 Elsevier Inc. All rights reserved.

Interference by 2,3,7,8-tetrachlorodibenzo-p-dioxin with cultured mouse submandibular gland branching morphogenesis involves reduced epidermal growth factor receptor signaling

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

Kiukkonen, Anu; Sahlberg, Carin; Partanen, Anna-Maija

2006-05-01

Toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) to mouse embryonic teeth, sharing features of early development with salivary glands in common, involves enhanced apoptosis and depends on the expression of epidermal growth factor (EGF) receptor. EGF receptor signaling, on the other hand, is essential for salivary gland branching morphogenesis. To see if TCDD impairs salivary gland morphogenesis and if the impairment is associated with EGF receptor signaling, we cultured mouse (NMRI) E13 submandibular glands with TCDD or TCDD in combination with EGF or fibronectin (FN), both previously found to enhance branching morphogenesis. Explants were examined stereomicroscopically and processed to paraffin sections. TCDD exposuremore » impaired epithelial branching and cleft formation, resulting in enlarged buds. The glands were smaller than normal. EGF and FN alone concentration-dependently stimulated or inhibited branching morphogenesis but when co-administered with TCDD, failed to compensate for its effect. TCDD induced cytochrome P4501A1 expression in the glandular epithelium, indicating activation of the aryl hydrocarbon receptor. TCDD somewhat increased epithelial apoptosis as observed by terminal deoxynucleotidyl transferase (TdT)-mediated nick end-labeling method but the increase could not be correlated with morphological changes. The frequency of proliferating cells was not altered. Corresponding to the reduced cleft sites in TCDD-exposed explants, FN immunoreactivity in the epithelium was reduced. The results show that TCDD, comparably with EGF and FN at morphogenesis-inhibiting concentrations, impaired salivary gland branching morphogenesis in vitro. Together with the failure of EGF and FN at morphogenesis-stimulating concentrations to compensate for the effect of TCDD this implies that TCDD toxicity to developing salivary gland involves reduced EGF receptor signaling.« less

Live imaging of heart tube development in mouse reveals alternating phases of cardiac differentiation and morphogenesis

PubMed Central

Ivanovitch, Kenzo; Temiño, Susana

2017-01-01

During vertebrate heart development, two progenitor populations, first and second heart fields (FHF, SHF), sequentially contribute to longitudinal subdivisions of the heart tube (HT), with the FHF contributing the left ventricle and part of the atria, and the SHF the rest of the heart. Here, we study the dynamics of cardiac differentiation and morphogenesis by tracking individual cells in live analysis of mouse embryos. We report that during an initial phase, FHF precursors differentiate rapidly to form a cardiac crescent, while limited morphogenesis takes place. In a second phase, no differentiation occurs while extensive morphogenesis, including splanchnic mesoderm sliding over the endoderm, results in HT formation. In a third phase, cardiac precursor differentiation resumes and contributes to SHF-derived regions and the dorsal closure of the HT. These results reveal tissue-level coordination between morphogenesis and differentiation during HT formation and provide a new framework to understand heart development. PMID:29202929

Un(MaSC)ing Stem Cell Dynamics in Mammary Branching Morphogenesis.

PubMed

Greenwood, Erin; Wrenn, Emma D; Cheung, Kevin J

2017-02-27

The properties of stem cells that participate in mammary gland branching morphogenesis remain contested. Reporting in Nature, Scheele et al. (2017) establish a model for post-pubertal mammary branching morphogenesis in which position-dependent, lineage-restricted stem cells undergo cell mixing in order to contribute to long-term growth. Copyright © 2017 Elsevier Inc. All rights reserved.

MT2-MMP-dependent release of collagen IV NC1 domains regulates submandibular gland branching morphogenesis

PubMed Central

Rebustini, Ivan T.; Myers, Christopher; Lassiter, Keyonica S.; Surmak, Andrew; Szabova, Ludmila; Holmbeck, Kenn; Pedchenko, Vadim; Hudson, Billy G.; Hoffman, Matthew P.

2009-01-01

Summary Proteolysis is essential during branching morphogenesis, but the roles of MT-MMPs and their proteolytic products are not clearly understood. Here we discover that decreasing MT-MMP activity during submandibular gland branching morphogenesis decreases proliferation and increases collagen IV and MT-MMP expression. Importantly, reducing epithelial MT2-MMP profoundly decreases proliferation and morphogenesis, increases Col4a2 and intracellular accumulation of collagen IV, and decreases the proteolytic release of collagen IV NC1 domains. Importantly, we demonstrate the presence of collagen IV NC1 domains in developing tissue. Furthermore, recombinant collagen IV NC1 domains rescue branching morphogenesis after MT2-siRNA-treatment, increasing MT-MMP and pro-proliferative gene expression via β1 integrin and PI3K-AKT signaling. Additionally, HBEGF also rescues MT2-siRNA-treatment, increasing NC1 domain release, proliferation, and MT2-MMP and Hbegf expression. Our studies provide mechanistic insight into how MT2-MMP-dependent release of bioactive NC1 domains from collagen IV is critical for integrating collagen IV synthesis and proteolysis with epithelial proliferation during branching morphogenesis. PMID:19853562

Melatonin Inhibits Embryonic Salivary Gland Branching Morphogenesis by Regulating Both Epithelial Cell Adhesion and Morphology

PubMed Central

Miura, Jiro; Sakai, Manabu; Uchida, Hitoshi; Nakamura, Wataru; Nohara, Kanji; Maruyama, Yusuke; Hattori, Atsuhiko; Sakai, Takayoshi

2015-01-01

Many organs, including salivary glands, lung, and kidney, are formed by epithelial branching during embryonic development. Branching morphogenesis occurs via either local outgrowths or the formation of clefts that subdivide epithelia into buds. This process is promoted by various factors, but the mechanism of branching morphogenesis is not fully understood. Here we have defined melatonin as a potential negative regulator or “brake” of branching morphogenesis, shown that the levels of it and its receptors decline when branching morphogenesis begins, and identified the process that it regulates. Melatonin has various physiological functions, including circadian rhythm regulation, free-radical scavenging, and gonadal development. Furthermore, melatonin is present in saliva and may have an important physiological role in the oral cavity. In this study, we found that the melatonin receptor is highly expressed on the acinar epithelium of the embryonic submandibular gland. We also found that exogenous melatonin reduces salivary gland size and inhibits branching morphogenesis. We suggest that this inhibition does not depend on changes in either proliferation or apoptosis, but rather relates to changes in epithelial cell adhesion and morphology. In summary, we have demonstrated a novel function of melatonin in organ formation during embryonic development. PMID:25876057

Rac1/RhoA antagonism defines cell-to-cell heterogeneity during epidermal morphogenesis in nematodes

PubMed Central

Ouellette, Marie-Hélène

2016-01-01

The antagonism between the GTPases Rac1 and RhoA controls cell-to-cell heterogeneity in isogenic populations of cells in vitro and epithelial morphogenesis in vivo. Its involvement in the regulation of cell-to-cell heterogeneity during epidermal morphogenesis has, however, never been addressed. We used a quantitative cell imaging approach to characterize epidermal morphogenesis at a single-cell level during early elongation of Caenorhabditis elegans embryos. This study reveals that a Rac1-like pathway, involving the Rac/Cdc42 guanine-exchange factor β-PIX/PIX-1 and effector PAK1/PAK-1, and a RhoA-like pathway, involving ROCK/LET-502, control the remodeling of apical junctions and the formation of basolateral protrusions in distinct subsets of hypodermal cells. In these contexts, protrusions adopt lamellipodia or an amoeboid morphology. We propose that lamella formation may reduce tension building at cell–cell junctions during morphogenesis. Cell-autonomous antagonism between these pathways enables cells to switch between Rac1- and RhoA-like morphogenetic programs. This study identifies the first case of cell-to-cell heterogeneity controlled by Rac1/RhoA antagonism during epidermal morphogenesis. PMID:27821782

Biological Effects of Orthodontic Tooth Movement Into the Grafted Alveolar Cleft.

PubMed

Sun, Jian; Zhang, Xiaoyue; Li, Renmei; Chen, Zhengxi; Huang, Yuanliang; Chen, Zhenqi

2018-03-01

Functional stimulus during orthodontic tooth movement into the grafted bone can lead to better alveolar bone grafting outcomes. The aim of this study was to analyze the biological effects of orthodontic tooth movement into the grafted alveolar cleft area with histologic staining, fluorescence staining, and real-time polymerase chain reaction (PCR). An animal model of orthodontic tooth movement into the grafted alveolar cleft area was established in 8-week-old Sprague-Dawley rats. The animals were divided into the experimental group and the control group. Four checkpoints were observed: before orthodontic stimuli, day 1 after orthodontic stimuli, day 3 after orthodontic stimuli, and day 5 after orthodontic stimuli. The cleft bone formation conditions, including the collagen fibers and the activities of the osteoclasts and osteoblasts, were evaluated by histologic staining. The expression of tartrate-resistant acid phosphatase (TRAP), receptor activator nuclear factor κB ligand, and Runt-related transcription factor 2 was detected by real-time PCR in both groups. Hematoxylin-eosin staining showed that the remodeling process of iliac autografts was completed when the orthodontic stress was applied, whereas the bone tissues first showed osteoclastogenesis and then osteogenesis. On the basis of TRAP staining, the osteoclasts increased to the maximal amount on day 3 and decreased thereafter. Evidence from tetracycline fluorescence staining indicated that no obvious changes in osteoblast activity were detected at the early stage; however, it gradually increased, especially in the region close to the root surface. According to real-time PCR, the expression of TRAP increased in both the early and middle stages, that of receptor activator nuclear factor κB ligand increased in the early stage, and that of Runt-related transcription factor 2 increased in the late stage. Moreover, the results showed significant differences between the experimental and control groups. Orthodontic tooth movement into the alveolar cleft bone graft area promoted bone remodeling of embedded bone, thus inducing bone resorption and subsequent deposition. Copyright © 2017. Published by Elsevier Inc.

36th Annual David W. Smith Workshop on Malformations and Morphogenesis: Abstracts of the 2015 annual meeting.

PubMed

Gripp, Karen W; Adam, Margaret P; Hudgins, Louanne; Carey, John C

2016-07-01

The 36th Annual David W Smith Workshop on Malformations and Morphogenesis was held on August 14-19, 2015 at the Harbourtowne Conference Center in St. Michaels Maryland. The Workshop, which honors the legacy of David W Smith, brought together over 120 clinicians and researchers interested in congenital malformations and their underlying mechanisms of morphogenesis. As is the tradition of the meeting, the Workshop highlighted five themes besides mechanisms of morphogenesis: Rasopathies, Eye Malformations, Therapeutics, Prenatal Diagnosis, and Disorders of Sex Development. This Conference Report includes the abstracts presented at the 2015 Workshop. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Extracellular matrix motion and early morphogenesis

PubMed Central

Loganathan, Rajprasad; Rongish, Brenda J.; Smith, Christopher M.; Filla, Michael B.; Czirok, Andras; Bénazéraf, Bertrand

2016-01-01

For over a century, embryologists who studied cellular motion in early amniotes generally assumed that morphogenetic movement reflected migration relative to a static extracellular matrix (ECM) scaffold. However, as we discuss in this Review, recent investigations reveal that the ECM is also moving during morphogenesis. Time-lapse studies show how convective tissue displacement patterns, as visualized by ECM markers, contribute to morphogenesis and organogenesis. Computational image analysis distinguishes between cell-autonomous (active) displacements and convection caused by large-scale (composite) tissue movements. Modern quantification of large-scale ‘total’ cellular motion and the accompanying ECM motion in the embryo demonstrates that a dynamic ECM is required for generation of the emergent motion patterns that drive amniote morphogenesis. PMID:27302396

SU-E-T-492: Implementing a Method for Brain Irradiation in Rats Utilizing a Commercially Available Radiosurgery Irradiator

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

Cates, J; Drzymala, R

2014-06-01

Purpose: The purpose of the study was to implement a method for accurate rat brain irradiation using the Gamma Knife Perfexion unit. The system needed to be repeatable, efficient, and dosimetrically and spatially accurate. Methods: A platform (“rat holder”) was made such that it is attachable to the Leskell Gamma Knife G Frame. The rat holder utilizes two ear bars contacting bony anatomy and a front tooth bar to secure the rat. The rat holder fits inside of the Leskell localizer box, which utilizes fiducial markers to register with the GammaPlan planning system. This method allows for accurate, repeatable setup.Amore » cylindrical phantom was made so that film can be placed axially in the phantom. We then acquired CT image sets of the rat holder and localizer box with both a rat and the phantom. Three treatment plans were created: a plan on the rat CT dataset, a phantom plan with the same prescription dose as the rat plan, and a phantom plan with the same delivery time as the rat plan. Results: Film analysis from the phantom showed that our setup is spatially accurate and repeatable. It is also dosimetrically accurate, with an difference between predicted and measured dose of 2.9%. Film analysis with prescription dose equal between rat and phantom plans showed a difference of 3.8%, showing that our phantom is a good representation of the rat for dosimetry purposes, allowing for +/- 3mm diameter variation. Film analysis with treatment time equal showed an error of 2.6%, which means we can deliver a prescription dose within 3% accuracy. Conclusion: Our method for irradiation of rat brain has been shown to be repeatable, efficient, and accurate, both dosimetrically and spatially. We can treat a large number of rats efficiently while delivering prescription doses within 3% at millimeter level accuracy.« less

Polycystin-1 Binds Par3/aPKC and Controls Convergent Extension During Renal Tubular Morphogenesis

PubMed Central

Castelli, Maddalena; Boca, Manila; Chiaravalli, Marco; Ramalingam, Harini; Rowe, Isaline; Distefano, Gianfranco; Carroll, Thomas; Boletta, Alessandra

2013-01-01

Several organs, including lungs and kidneys, are formed by epithelial tubes whose proper morphogenesis ensures correct function. This is best exemplified by the kidney, where defective establishment or maintanance of tubular diameter results in polycystic kidney disease, a common genetic disorder. Most polycystic kidney disease cases result from loss-of-function mutations in the PKD1 gene, encoding Polycystin-1 (PC-1), a large receptor of unknown function. Here we demonstrate that PC-1 plays an essential role in establishment of correct tubular diameter during nephron development. PC-1 associates with Par3 favoring the assembly of a pro-polarizing Par3/aPKC complex and it regulates a program of cell polarity important for oriented cell migration and for a convergent extension-like process during tubular morphogenesis. Par3 inactivation in the developing kidney results in defective convergent extension and tubular morphogenesis and in renal cyst formation. Our data define PC-1 as central to cell polarization and to epithelial tube morphogenesis and homeostasis. PMID:24153433

Polycystin-1 binds Par3/aPKC and controls convergent extension during renal tubular morphogenesis

NASA Astrophysics Data System (ADS)

Castelli, Maddalena; Boca, Manila; Chiaravalli, Marco; Ramalingam, Harini; Rowe, Isaline; Distefano, Gianfranco; Carroll, Thomas; Boletta, Alessandra

2013-10-01

Several organs, including the lungs and kidneys, are formed by epithelial tubes whose proper morphogenesis ensures correct function. This is best exemplified by the kidney, where defective establishment or maintenance of tubular diameter results in polycystic kidney disease, a common genetic disorder. Most polycystic kidney disease cases result from loss-of-function mutations in the PKD1 gene, encoding Polycystin-1, a large receptor of unknown function. Here we demonstrate that PC-1 has an essential role in the establishment of correct tubular diameter during nephron development. Polycystin-1 associates with Par3 favouring the assembly of a pro-polarizing Par3/aPKC complex and it regulates a programme of cell polarity important for oriented cell migration and for a convergent extension-like process during tubular morphogenesis. Par3 inactivation in the developing kidney results in defective convergent extension and tubular morphogenesis, and in renal cyst formation. Our data define Polycystin-1 as central to cell polarization and to epithelial tube morphogenesis and homeostasis.

Strontium coating by electrochemical deposition improves implant osseointegration in osteopenic models

PubMed Central

LIANG, YONGQIANG; LI, HAOYAN; XU, JIANG; LI, XIN; LI, XINCHANG; YAN, YUTING; QI, MENGCHUN; HU, MIN

2015-01-01

Osteopenia, a preclinical state of osteoporosis, restricts the application of adult orthodontic implant anchorage and tooth implantation. Strontium (Sr) is able to promote bone formation and inhibit bone absorption. The aim of the present study was to evaluate a new method for improving the success rate of dental implantation. In this study, an electrochemical deposition (ECD) method was used to prepare a Sr coating on a titanium implant. The coating composition was investigated by energy dispersive X-ray spectroscopy and X-ray diffraction, and the surface morphology of the coating was studied using scanning electron microscopy. A total of 24 Sprague-Dawley rats received bilateral ovariectomy (OVX) and an additional 12 rats underwent a sham surgery. All rats were then implanted in the bilateral tibiae with titanium mini-implants with or without a Sr coating. The results of histological examination and a fluorescence double labeling assay showed strong new bone formation with a wider zone between the double labels, a higher rate of bone mineralization and better osseointegration in the OVX rats that received Sr-coated implants compared with the OVX rats that received uncoated implants. The study indicates that Sr coatings are easily applied by an ECD method, and that Sr coatings have a promoting effect on implant osseointegration in animals with osteopenia. PMID:25452797

Identification and Expression of Acetylcholinesterase in Octopus vulgaris Arm Development and Regeneration: a Conserved Role for ACHE?

PubMed

Fossati, Sara Maria; Candiani, Simona; Nödl, Marie-Therese; Maragliano, Luca; Pennuto, Maria; Domingues, Pedro; Benfenati, Fabio; Pestarino, Mario; Zullo, Letizia

2015-08-01

Acetylcholinesterase (ACHE) is a glycoprotein with a key role in terminating synaptic transmission in cholinergic neurons of both vertebrates and invertebrates. ACHE is also involved in the regulation of cell growth and morphogenesis during embryogenesis and regeneration acting through its non-cholinergic sites. The mollusk Octopus vulgaris provides a powerful model for investigating the mechanisms underlying tissue morphogenesis due to its high regenerative power. Here, we performed a comparative investigation of arm morphogenesis during adult arm regeneration and embryonic arm development which may provide insights on the conserved ACHE pathways. In this study, we cloned and characterized O. vulgaris ACHE, finding a single highly conserved ACHE hydrophobic variant, characterized by prototypical catalytic sites and a putative consensus region for a glycosylphosphatidylinositol (GPI)-anchor attachment at the COOH-terminus. We then show that its expression level is correlated to the stage of morphogenesis in both adult and embryonic arm. In particular, ACHE is localized in typical neuronal sites when adult-like arm morphology is established and in differentiating cell locations during the early stages of arm morphogenesis. This possibility is also supported by the presence in the ACHE sequence and model structure of both cholinergic and non-cholinergic sites. This study provides insights into ACHE conserved roles during processes of arm morphogenesis. In addition, our modeling study offers a solid basis for predicting the interaction of the ACHE domains with pharmacological blockers for in vivo investigations. We therefore suggest ACHE as a target for the regulation of tissue morphogenesis.

MyD88 expression in the rat dental follicle: Implications for osteoclastogenesis and tooth eruption

PubMed Central

Liu, Dawen; Yao, Shaomian; Wise, Gary E.

2010-01-01

Myeloid differentiation factor 88 (MyD88) is a key adaptor molecule in the interleukin-1 (IL-1) and IL-18 Toll-like receptor signaling pathway. Because it is present in dental follicle (DF) cells in vitro, the purpose of this study was to determine its chronological expression in vivo, as well as its possible role in osteoclastogenesis and tooth eruption. An oligo DNA microarray was used to determine gene expression of MyD88 in vivo in the DFs from the first mandibular molars of postnatal rats from days 1–11. The results showed that MyD88 was expressed maximally at day 3. Using siRNA to knock down MyD88 expression in the DF cells also reduced the gene expression of nuclear factor-kappa B-1 (NFKB1) and monocyte chemoattractant protein 1 (MCP-1). IL-1α up-regulated the expression of NFKB1, MCP-1 and receptor activator of nuclear factor kappa B ligand (RANKL), but knockdown of MyD88 nullified this IL-1α effect. Conditioned medium from DF cells with MyD88 knocked down reduced chemotactic activity for mononuclear cells and reduced osteoclastogenesis as opposed to controls. In conclusion, the maximal expression of MyD88 at day 3 in the DF may contribute to the major burst of osteoclastogenesis needed for eruption by up-regulating MCP-1 and RANKL expression. PMID:20662905

In vivo microcomputed tomography evaluation of rat alveolar bone and root resorption during orthodontic tooth movement.

PubMed

Ru, Nan; Liu, Sean Shih-Yao; Zhuang, Li; Li, Song; Bai, Yuxing

2013-05-01

To observe the real-time microarchitecture changes of the alveolar bone and root resorption during orthodontic treatment. A 10 g force was delivered to move the maxillary left first molars mesially in twenty 10-week-old rats for 14 days. The first molar and adjacent alveolar bone were scanned using in vivo microcomputed tomography at the following time points: days 0, 3, 7, and 14. Microarchitecture parameters, including bone volume fraction, structure model index, trabecular thickness, trabecular number, and trabecular separation of alveolar bone, were measured on the compression and tension side. The total root volume was measured, and the resorption crater volume at each time point was calculated. Univariate repeated measures analysis of variance with Bonferroni corrections were performed to compare the differences in each parameter between time points with significance level at P < .05. From day 3 to day 7, bone volume fraction, structure model index, trabecular thickness, and trabecular separation decreased significantly on the compression side, but the same parameters increased significantly on the tension side from day 7 to day 14. Root resorption volume of the mesial root increased significantly on day 7 of orthodontic loading. Real-time root and bone resorption during orthodontic movement can be observed in 3 dimensions using in vivo micro-CT. Alveolar bone resorption and root resorption were observed mostly in the apical third on day 7 on the compression side; bone formation was observed on day 14 on the tension side during orthodontic tooth movement.

Caffeine may enhance orthodontic tooth movement through increasing osteoclastogenesis induced by periodontal ligament cells under compression.

PubMed

Yi, Jianru; Yan, Boxi; Li, Meile; Wang, Yu; Zheng, Wei; Li, Yu; Zhao, Zhihe

2016-04-01

Caffeine is the kernel component of coffee and has multiple effects on bone metabolism. Here we aimed to investigate the effects of caffeine intake on orthodontic tooth movement (OTM). (1) In the in vivo study, two groups comprising 15 randomly assigned rats each underwent orthodontic treatment. One group ingested caffeine at 25mg/kg body weight per day and the other, plain water. After 3 weeks, the degree of tooth movement and effect on the periodontium were assessed. (2) In the in vitro study, we established a model mimicking the essential bioprocess of OTM, which contained a periodontal ligament tissue model (PDLtm), and a co-culture system of osteoblasts (OBs) and osteoclast precursors (pre-OCs). After being subjected to static compressive force with or without caffeine administration, the conditioned media from the PDLtm were used for the OB/pre-OC co-cultures to induce osteoclastogenesis. (1) In vivo, the caffeine group displayed a significantly greater rate of tooth movement than the control. The alveolar bone mineral density and bone volume fraction were similar between the two groups; however, immunohistochemical staining showed that the caffeine group had significantly more TRAP(+) osteoclasts and higher RANKL expression in the compressed periodontium. (2) In vitro, caffeine at 0.01mM significantly enhanced the compression-induced expression of RANKL and COX-2, as well as prostaglandin E2 production in the PDLtm. Furthermore, the "caffeine+compression"-conditioned media induced significantly more TRAP(+) OC formation when compared with compression alone. Daily intake of caffeine, at least at some specific dosage, may enhance OTM through increasing osteoclastogenesis. Copyright © 2016 Elsevier Ltd. All rights reserved.

The effect of silver nanoparticles on apoptosis and dark neuron production in rat hippocampus

PubMed Central

Bagheri-abassi, Farzaneh; Alavi, Hassan; Mohammadipour, Abbas; Motejaded, Fatemeh; Ebrahimzadeh-bideskan, Alireza

2015-01-01

Objective(s): Silver nanoparticles (Ag-NPs) are used widely in bedding, water purification, tooth paste and toys. These nanoparticles can enter into the body and move into the hippocampus. The aim of this study was to investigate the neurotoxicity of silver nanoparticles in the adult rat hippocampus. Materials and Methods: 12 male Wistar rats were randomly divided into two experimental and control groups (6 rats in each group). Animals in the experimental group received Ag-NPs (30 mg/kg) orally (gavage) for 28 consecutive days. Control group in the same period was treated with distilled water via gavage. At the end of experiment, animals were deeply anesthetized, sacrificed, and their brains were collected from each group. Finally the brain sections were stained using toluidine blue and TUNEL. Then to compare the groups, dark neurons (DNs) and apoptotic neurons were counted by morphometric method. Results: Results showed that the numbers of DNs and apoptotic cells in the CA1, CA2, CA3, and dentate gyrus (DG) of hippocampus significantly increased in the Ag-NPs group in comparison to the control group (P<0.05). Conclusion: Exposure to Ag-NPs can induce dark neuron and apoptotic cells in the hippocampus. PMID:26351553

Extracellular matrix motion and early morphogenesis.

PubMed

Loganathan, Rajprasad; Rongish, Brenda J; Smith, Christopher M; Filla, Michael B; Czirok, Andras; Bénazéraf, Bertrand; Little, Charles D

2016-06-15

For over a century, embryologists who studied cellular motion in early amniotes generally assumed that morphogenetic movement reflected migration relative to a static extracellular matrix (ECM) scaffold. However, as we discuss in this Review, recent investigations reveal that the ECM is also moving during morphogenesis. Time-lapse studies show how convective tissue displacement patterns, as visualized by ECM markers, contribute to morphogenesis and organogenesis. Computational image analysis distinguishes between cell-autonomous (active) displacements and convection caused by large-scale (composite) tissue movements. Modern quantification of large-scale 'total' cellular motion and the accompanying ECM motion in the embryo demonstrates that a dynamic ECM is required for generation of the emergent motion patterns that drive amniote morphogenesis. © 2016. Published by The Company of Biologists Ltd.

Perinatal xenohormone exposure impacts sweet preference and submandibular development in male rats.

PubMed

Kouidhi, W; Bergès, R; Tiffon, C; Desmetz, C; El May, M; Auger, J; Canivenc-Lavier, Mc

2013-11-01

To determine the effect of perinatal exposure to low doses of genistein and/or vinclozolin on submandibular salivary gland (SSG) development in juvenile and adult male rats and to establish a link with sweet preference. Female rats received orally (1 mg kg(-1) body weight/day) genistein and vinclozolin, alone or in combination, from the first gestational day up to weaning. Sweet preference was assessed at weaning and in adulthood in male offspring; submandibular glands were then collected to study the morphogenesis and mRNA expression of steroid receptors, growth factors and taste related proteins. Exposure to genistein and/or vinclozolin resulted in a higher saccharin intake on postnatal day 25 (P < 0.05) linked to a higher number of pro-acinar cells (P < 0.01) and mRNA expression of progesterone receptor, growth factors and gustine (P < 0.01). These increases disappeared in adulthood, but mRNA expressions of sex hormone receptors and growth factors were strongly repressed in all treated groups (P < 0.01). Our findings confirm that the SSG are target for xenohormones and provide evidence that perinatal exposure to low doses of genistein and/or vinclozolin could simultaneously disrupt not only the salivary gland prepubertal development and sweet intake but also endocrine gene mRNA expression later in life. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Absence of αvβ6 Integrin Is Linked to Initiation and Progression of Periodontal Disease

PubMed Central

Ghannad, Farzin; Nica, Daniela; Garcia Fulle, Maria I.; Grenier, Daniel; Putnins, Edward E.; Johnston, Sarah; Eslami, Ameneh; Koivisto, Leeni; Jiang, Guoqiao; McKee, Marc D.; Häkkinen, Lari; Larjava, Hannu

2008-01-01

Integrin αvβ6 is generally not expressed in adult epithelia but is induced in wound healing, cancer, and certain fibrotic disorders. Despite this generalized absence, we observed that αvβ6 integrin is constitutively expressed in the healthy junctional epithelium linking the gingiva to tooth enamel. Moreover, expression of αvβ6 integrin was down-regulated in human periodontal disease, a common medical condition causing tooth loss and also contributing to the development of cardiovascular diseases by increasing the total systemic inflammatory burden. Remarkably, integrin β6 knockout mice developed classic signs of spontaneous, chronic periodontal disease with characteristic inflammation, epithelial down-growth, pocket formation, and bone loss around the teeth. Integrin αvβ6 acts as a major activator of transforming growth factor-β1 (TGF-β1), a key anti-inflammatory regulator in the immune system. Co-expression of TGF-β1 and αvβ6 integrin was observed in the healthy junctional epithelium. Moreover, an antibody that blocks αvβ6 integrin-mediated activation of TGF-β1 initiated inflammatory periodontal disease in a rat model of gingival inflammation. Thus, αvβ6 integrin is constitutively expressed in the epithelium sealing the gingiva to the tooth and plays a central role in protection against inflammatory periodontal disease through activation of TGF-β1. PMID:18385522

Amniotic fluid derived mesenchymal stromal cells augment fetal lung growth in a nitrofen explant model.

PubMed

Di Bernardo, Julie; Maiden, Michael M; Hershenson, Marc B; Kunisaki, Shaun M

2014-06-01

Recent experimental work suggests the therapeutic role of mesenchymal stromal cells (MSCs) during lung morphogenesis. The purpose of this study was to investigate the potential paracrine effects of amniotic fluid-derived MSCs (AF-MSCs) on fetal lung growth in a nitrofen explant model. Pregnant Sprague-Dawley dams were gavage fed nitrofen on gestational day 9.5 (E9.5). E14.5 lung explants were subsequently harvested and cultured ex vivo for three days on filter membranes in conditioned media from rat AF-MSCs isolated from control (AF-Ctr) or nitrofen-exposed (AF-Nitro) dams. The lungs were analyzed morphometrically and by quantitative gene expression. Although there were no significant differences in total lung surface area among hypoplastic lungs, there were significant increases in terminal budding among E14.5+3 nitrofen explants exposed to AF-Ctr compared to explants exposed to medium alone (58.8±8.4 vs. 39.0±10.0 terminal buds, respectively; p<0.05). In contrast, lungs cultured in AF-Nitro medium failed to augment terminal budding. Nitrofen explants exposed to AF-Ctr showed significant upregulation of surfactant protein C to levels observed in normal fetal lungs. AF-MSCs can augment branching morphogenesis and lung epithelial maturation in a fetal explant model of pulmonary hypoplasia. Cell therapy using donor-derived AF-MSCs may represent a novel strategy for the treatment of fetal congenital diaphragmatic hernia. Copyright © 2014 Elsevier Inc. All rights reserved.

A global sensitivity analysis approach for morphogenesis models.

PubMed

Boas, Sonja E M; Navarro Jimenez, Maria I; Merks, Roeland M H; Blom, Joke G

2015-11-21

Morphogenesis is a developmental process in which cells organize into shapes and patterns. Complex, non-linear and multi-factorial models with images as output are commonly used to study morphogenesis. It is difficult to understand the relation between the uncertainty in the input and the output of such 'black-box' models, giving rise to the need for sensitivity analysis tools. In this paper, we introduce a workflow for a global sensitivity analysis approach to study the impact of single parameters and the interactions between them on the output of morphogenesis models. To demonstrate the workflow, we used a published, well-studied model of vascular morphogenesis. The parameters of this cellular Potts model (CPM) represent cell properties and behaviors that drive the mechanisms of angiogenic sprouting. The global sensitivity analysis correctly identified the dominant parameters in the model, consistent with previous studies. Additionally, the analysis provided information on the relative impact of single parameters and of interactions between them. This is very relevant because interactions of parameters impede the experimental verification of the predicted effect of single parameters. The parameter interactions, although of low impact, provided also new insights in the mechanisms of in silico sprouting. Finally, the analysis indicated that the model could be reduced by one parameter. We propose global sensitivity analysis as an alternative approach to study the mechanisms of morphogenesis. Comparison of the ranking of the impact of the model parameters to knowledge derived from experimental data and from manipulation experiments can help to falsify models and to find the operand mechanisms in morphogenesis. The workflow is applicable to all 'black-box' models, including high-throughput in vitro models in which output measures are affected by a set of experimental perturbations.

Extracellular matrix and growth factors in branching morphogenesis

NASA Technical Reports Server (NTRS)

Hardman, P.; Spooner, B. S.

1993-01-01

The unifying hypothesis of the NSCORT in gravitational biology postulates that the ECM and growth factors are key interrelated components of a macromolecular regulatory system. The ECM is known to be important in growth and branching morphogenesis of embryonic organs. Growth factors have been detected in the developing embryo, and often the pattern of localization is associated with areas undergoing epithelial-mesenchymal interactions. Causal relationships between these components may be of fundamental importance in control of branching morphogenesis.

Genetic Interaction of Centrosomin and Bazooka in Apical Domain Regulation in Drosophila Photoreceptor

PubMed Central

Chen, Geng; Rogers, Alicia K.; League, Garrett P.; Nam, Sang-Chul

2011-01-01

Background Cell polarity genes including Crumbs (Crb) and Par complexes are essential for controlling photoreceptor morphogenesis. Among the Crb and Par complexes, Bazooka (Baz, Par-3 homolog) acts as a nodal component for other cell polarity proteins. Therefore, finding other genes interacting with Baz will help us to understand the cell polarity genes' role in photoreceptor morphogenesis. Methodology/Principal Findings Here, we have found a genetic interaction between baz and centrosomin (cnn). Cnn is a core protein for centrosome which is a major microtubule-organizing center. We analyzed the effect of the cnn mutation on developing eyes to determine its role in photoreceptor morphogenesis. We found that Cnn is dispensable for retinal differentiation in eye imaginal discs during the larval stage. However, photoreceptors deficient in Cnn display dramatic morphogenesis defects including the mislocalization of Crumbs (Crb) and Bazooka (Baz) during mid-stage pupal eye development, suggesting that Cnn is specifically required for photoreceptor morphogenesis during pupal eye development. This role of Cnn in apical domain modulation was further supported by Cnn's gain-of-function phenotype. Cnn overexpression in photoreceptors caused the expansion of the apical Crb membrane domain, Baz and adherens junctions (AJs). Conclusions/Significance These results strongly suggest that the interaction of Baz and Cnn is essential for apical domain and AJ modulation during photoreceptor morphogenesis, but not for the initial photoreceptor differentiation in the Drosophila photoreceptor. PMID:21253601

Mis-expression of grainyhead-like transcription factors in zebrafish leads to defects in enveloping layer (EVL) integrity, cellular morphogenesis and axial extension.

PubMed

Miles, Lee B; Darido, Charbel; Kaslin, Jan; Heath, Joan K; Jane, Stephen M; Dworkin, Sebastian

2017-12-14

The grainyhead-like (grhl) transcription factors play crucial roles in craniofacial development, epithelial morphogenesis, neural tube closure, and dorso-ventral patterning. By utilising the zebrafish to differentially regulate expression of family members grhl2b and grhl3, we show that both genes regulate epithelial migration, particularly convergence-extension (CE) type movements, during embryogenesis. Genetic deletion of grhl3 via CRISPR/Cas9 results in failure to complete epiboly and pre-gastrulation embryonic rupture, whereas morpholino (MO)-mediated knockdown of grhl3 signalling leads to aberrant neural tube morphogenesis at the midbrain-hindbrain boundary (MHB), a phenotype likely due to a compromised overlying enveloping layer (EVL). Further disruptions of grhl3-dependent pathways (through co-knockdown of grhl3 with target genes spec1 and arhgef19) confirm significant MHB morphogenesis and neural tube closure defects. Concomitant MO-mediated disruption of both grhl2b and grhl3 results in further extensive CE-like defects in body patterning, notochord and somite morphogenesis. Interestingly, over-expression of either grhl2b or grhl3 also leads to numerous phenotypes consistent with disrupted cellular migration during gastrulation, including embryo dorsalisation, axial duplication and impaired neural tube migration leading to cyclopia. Taken together, our study ascribes novel roles to the Grhl family in the context of embryonic development and morphogenesis.

Cell confinement controls centrosome positioning and lumen initiation during epithelial morphogenesis

PubMed Central

Rodríguez-Fraticelli, Alejo E.; Auzan, Muriel; Alonso, Miguel A.; Bornens, Michel

2012-01-01

Epithelial organ morphogenesis involves sequential acquisition of apicobasal polarity by epithelial cells and development of a functional lumen. In vivo, cells perceive signals from components of the extracellular matrix (ECM), such as laminin and collagens, as well as sense physical conditions, such as matrix stiffness and cell confinement. Alteration of the mechanical properties of the ECM has been shown to promote cell migration and invasion in cancer cells, but the effects on epithelial morphogenesis have not been characterized. We analyzed the effects of cell confinement on lumen morphogenesis using a novel, micropatterned, three-dimensional (3D) Madin-Darby canine kidney cell culture method. We show that cell confinement, by controlling cell spreading, limits peripheral actin contractility and promotes centrosome positioning and lumen initiation after the first cell division. In addition, peripheral actin contractility is mediated by master kinase Par-4/LKB1 via the RhoA–Rho kinase–myosin II pathway, and inhibition of this pathway restores lumen initiation in minimally confined cells. We conclude that cell confinement controls nuclear–centrosomal orientation and lumen initiation during 3D epithelial morphogenesis. PMID:22965908

Synthetic Morphogenesis.

PubMed

Teague, Brian P; Guye, Patrick; Weiss, Ron

2016-09-01

Throughout biology, function is intimately linked with form. Across scales ranging from subcellular to multiorganismal, the identity and organization of a biological structure's subunits dictate its properties. The field of molecular morphogenesis has traditionally been concerned with describing these links, decoding the molecular mechanisms that give rise to the shape and structure of cells, tissues, organs, and organisms. Recent advances in synthetic biology promise unprecedented control over these molecular mechanisms; this opens the path to not just probing morphogenesis but directing it. This review explores several frontiers in the nascent field of synthetic morphogenesis, including programmable tissues and organs, synthetic biomaterials and programmable matter, and engineering complex morphogenic systems de novo. We will discuss each frontier's objectives, current approaches, constraints and challenges, and future potential. Copyright © 2016 Cold Spring Harbor Laboratory Press; all rights reserved.

Prenatal retinoic acid upregulates pulmonary gene expression of PI3K and AKT in nitrofen-induced pulmonary hypoplasia.

PubMed

Doi, Takashi; Sugimoto, Kaoru; Ruttenstock, Elke; Dingemann, Jens; Puri, Prem

2010-10-01

The precise mechanism of pulmonary hypoplasia associated with congenital diaphragmatic hernia (CDH) still remains unclear. Recently, prenatal treatment with retinoic acid (RA) has been reported to stimulate alveologenesis in hypoplastic lungs in the nitrofen model of CDH. The serine/threonine protein kinase B (AKT) plays a key role in lung morphogenesis through epithelial-mesenchymal interaction in phosphatidylinositide 3-kinase (PI3K)-dependent manner. It has been reported that the lung morphogenesis in explants in mice is interfered by inhibitors of PI3K-AKT signaling pathway. Furthermore, we have recently shown that nitrofen inhibits PI3K-AKT signaling during mid-to-late lung morphogenesis in the nitrofen-induced hypoplastic lung. We hypothesized that prenatal administration of RA upregulates pulmonary gene expression of PI3K and AKT in the nitrofen-induced hypoplastic lung. Pregnant rats were exposed to either olive oil or nitrofen on day 9 of gestation (D9). 5 mg/kg of RA was given on D18, D19 and D20. The fetuses were harvested on D21, and fetal lungs were obtained and divided into four groups: control, control + RA, nitrofen, nitrofen + RA. The mRNA expression levels of PI3K and AKT were analyzed in each lung by real-time RT-PCR and statistically analyzed. Immunohistochemistry was also performed to evaluate protein expression of PI3K and AKT in the fetal lungs at D21. The pulmonary gene expression levels of PI3K and AKT were significantly upregulated in nitrofen + RA group compared to nitrofen group and control + RA group (p < 0.05), whereas there were no significant differences between controls and control + RA group. Immunoreactivity of PI3K and AKT was markedly increased in nitrofen + RA lungs compared to nitrofen-induced hypoplastic lungs. Upregulation of PI3K and AKT genes after prenatal treatment with RA in the nitrofen-induced hypoplastic lung suggests that RA may have a therapeutic potential in modulating lung alveologenesis by stimulating epithelial-mesenchymal interaction via PI3K-AKT signaling.

The Effect of An Angiogenic Cytokine on Orthodontically Induced Inflammatory Root Resorption

PubMed Central

Seifi, Massoud; Lotfi, Ali; Badiee, Mohammad Reza; Abdolazimi, Zahra; Amdjadi, Parisa; Bargrizan, Majid

2016-01-01

Objective Orthodontically induced inflammatory root resorption (OIIRR) is an undesirable sequel of tooth movement after sterile necrosis that takes place in periodontal ligament due to blockage of blood vessels following exertion of orthodontic force. This study sought to assess the effect of an angiogenic cytokine on OIIRR in rat model. Materials and Methods In this experimental animal study, 50 rats were randomly divided into 5 groups of 10 each: E10, E100 and E1000 receiving an injection of 10, 100 and 1000 ng of basic fibroblast growth factor (bFGF), respectively, positive control group (CP) receiving an orthodontic appliance and injection of phosphate buffered saline (PBS) and the negative control group (CN) receiving only the anesthetic agent. A nickel titanium coil spring was placed between the first molar and the incisor on the right side of maxilla. Twenty-one days later, the rats were sacrificed. Histopathological sections were made to assess the number and area of resorption lacunae, number of blood vessels, osteoclasts and Howship’s lacunae. Data were statistically analyzed using ANOVA and Tukey’s honest significant difference (HSD) test. Results Number of resorption lacunae and area of resorption lacunae in E1000 (0.97 ± 0.80 and 1. 27 ± 0.01×10-3, respectively) were significantly lower than in CP (4.17 ± 0.90 and 2.77 ± 0.01×10-3, respectively, P=0.000). Number of blood vessels, osteoclasts and Howship’s lacunae were significantly higher in E1000 compared to CP (P<0.05). Conclusion Tooth movement as the outcome of bone remodeling is concomitant with the formation of sterile necrosis in the periodontal ligament following blocked blood supply. Thus, bFGF can significantly decrease the risk of root resorption by providing more oxygen and angiogenesis. PMID:27551674

Strain-guided mineralization in the bone–PDL–cementum complex of a rat periodontium

DOE PAGES

Grandfield, Kathryn; Herber, Ralf -Peter; Chen, Ling; ...

2015-04-18

Objective: The objective of this study was to investigate the effect of mechanical strain by mapping physicochemical properties at periodontal ligament (PDL)–bone and PDL–cementum attachment sites and within the tissues per se. Design: Accentuated mechanical strain was induced by applying a unidirectional force of 0.06 N for 14 days on molars in a rat model. The associated changes in functional space between the tooth and bone, mineral forming and resorbing events at the PDL–bone and PDL–cementum attachment sites were identified by using micro-X-ray computed tomography (micro-XCT), atomic force microscopy (AFM), dynamic histomorphometry, Raman microspectroscopy, and AFM-based nanoindentation technique. Results frommore » these analytical techniques were correlated with histochemical strains specific to low and high molecular weight GAGs, including biglycan, and osteoclast distribution through tartrate resistant acid phosphatase (TRAP) staining. Results: Unique chemical and mechanical qualities including heterogeneous bony fingers with hygroscopic Sharpey's fibers contributing to a higher organic (amide III — 1240 cm⁻¹) to inorganic (phosphate — 960 cm⁻¹) ratio, with lower average elastic modulus of 8 GPa versus 12 GPa in unadapted regions were identified. Furthermore, an increased presence of elemental Zn in cement lines and mineralizing fronts of PDL–bone was observed. Adapted regions containing bony fingers exhibited woven bone-like architecture and these regions rich in biglycan (BGN) and bone sialoprotein (BSP) also contained high-molecular weight polysaccharides predominantly at the site of polarized bone growth. Conclusions: From a fundamental science perspective the shift in local properties due to strain amplification at the soft–hard tissue attachment sites is governed by semiautonomous cellular events at the PDL–bone and PDL–cementum sites. Over time, these strain-mediated events can alter the physicochemical properties of tissues per se, and consequently the overall biomechanics of the bone–PDL–tooth complex. From a clinical perspective, the shifts in magnitude and duration of forces on the periodontal ligament can prompt a shift in physiologic mineral apposition in cementum and alveolar bone albeit of an adapted quality owing to the rapid mechanical translation of the tooth.« less

Strain-guided mineralization in the bone–PDL–cementum complex of a rat periodontium

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

Grandfield, Kathryn; Herber, Ralf -Peter; Chen, Ling

Objective: The objective of this study was to investigate the effect of mechanical strain by mapping physicochemical properties at periodontal ligament (PDL)–bone and PDL–cementum attachment sites and within the tissues per se. Design: Accentuated mechanical strain was induced by applying a unidirectional force of 0.06 N for 14 days on molars in a rat model. The associated changes in functional space between the tooth and bone, mineral forming and resorbing events at the PDL–bone and PDL–cementum attachment sites were identified by using micro-X-ray computed tomography (micro-XCT), atomic force microscopy (AFM), dynamic histomorphometry, Raman microspectroscopy, and AFM-based nanoindentation technique. Results frommore » these analytical techniques were correlated with histochemical strains specific to low and high molecular weight GAGs, including biglycan, and osteoclast distribution through tartrate resistant acid phosphatase (TRAP) staining. Results: Unique chemical and mechanical qualities including heterogeneous bony fingers with hygroscopic Sharpey's fibers contributing to a higher organic (amide III — 1240 cm⁻¹) to inorganic (phosphate — 960 cm⁻¹) ratio, with lower average elastic modulus of 8 GPa versus 12 GPa in unadapted regions were identified. Furthermore, an increased presence of elemental Zn in cement lines and mineralizing fronts of PDL–bone was observed. Adapted regions containing bony fingers exhibited woven bone-like architecture and these regions rich in biglycan (BGN) and bone sialoprotein (BSP) also contained high-molecular weight polysaccharides predominantly at the site of polarized bone growth. Conclusions: From a fundamental science perspective the shift in local properties due to strain amplification at the soft–hard tissue attachment sites is governed by semiautonomous cellular events at the PDL–bone and PDL–cementum sites. Over time, these strain-mediated events can alter the physicochemical properties of tissues per se, and consequently the overall biomechanics of the bone–PDL–tooth complex. From a clinical perspective, the shifts in magnitude and duration of forces on the periodontal ligament can prompt a shift in physiologic mineral apposition in cementum and alveolar bone albeit of an adapted quality owing to the rapid mechanical translation of the tooth.« less

Antidiabetic activity and phytochemical screening of crude extract of Stevia rebaudiana in alloxan-induced diabetic rats

PubMed Central

Kujur, R. S.; Singh, Vishakha; Ram, Mahendra; Yadava, Harlokesh Narayan; Singh, K. K.; Kumari, Suruchi; Roy, B. K.

2010-01-01

Background: Stevia rebaudiana regulates blood sugar, prevents hypertension and tooth decay. Other studies have shown that it has antibacterial as well as antiviral property. Methods: Preliminary phytochemical screening of aqueous, ether and methanolic extracts of S. rebaudiana was done. Acute and sub-acute toxicity were conducted on twenty four Albino rats, divided into one control (Group I) and three treatment groups viz. aqueous extract (Group II), ether extract (Group III) and methanolic extract (Group IV). For the study of antidiabetic effect of S. rebaudiana rats were divided into seven groups (n=6). Diabetes was induced by a single dose of 5% alloxan monohydrate (125 mg/kg, i.p.) after 24 hour fasting.Blood samples were analysed on day 0, 1, 5, 7, 14 and 28. Results: Phytochemical tests showed presence of different kinds of phyto-constituents in aqueous, ether and methanol extract of Stevia rebaudiana leaves. Daily single dose (2.0 g/kg) administration of aqueous extract (A.E.) , ether extract (E.E.) and methanol extract (M.E.) for 28 days of S. rebaudiana could not show any significant change in ALT and AST levels in rats. Blood sugar level was found to be decreased on day 28 in groups of rats treated with A.E., E.E. and M.E. of S. rebaudiana. Conclusion: The extracts of Stevioside rebaudiana could decrease the blood glucose level in diabetic rats in time dependent manner. PMID:21808578

Endotoxin-induced nitric oxide production rescues airway growth and maturation in atrophic fetal rat lung explants

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

Rae, C.; Cherry, J.I.; Land, F.M.

Inflammation induces premature maturation of the fetal lung but the signals causing this effect remain unclear. We determined if nitric oxide (NO) synthesis, evoked by Escherichia coli lipopolysaccharide (LPS, 2 {mu}g ml{sup -1}), participated in this process. Fetal rat lung airway surface complexity rose 2.5-fold over 96 h in response to LPS and was associated with increased iNOS protein expression and activity. iNOS inhibition by N6-(1-iminoethyl)-L-lysine-2HCl (L-NIL) abolished this and induced airway atrophy similar to untreated explants. Surfactant protein-C (SP-C) expression was also induced by LPS and abolished by L-NIL. As TGF{beta} suppresses iNOS activity, we determined if feedback regulationmore » modulated NO-dependent maturation. LPS induced TGF{beta}1 release and SMAD4 nuclear translocation 96 h after treatment. Treatment of explants with a blocking antibody against TGF{beta}1 sustained NO production and airway morphogenesis whereas recombinant TGF{beta}1 antagonized these effects. Feedback regulation of NO synthesis by TGF{beta} may, thus, modulate airway branching and maturation of the fetal lung.« less

Bone mineralization and vascularization in bisphosphonate-related osteonecrosis of the jaw: an experimental study in the rat.

PubMed

Kün-Darbois, Jean-Daniel; Libouban, Hélène; Mabilleau, Guillaume; Pascaretti-Grizon, Florence; Chappard, Daniel

2018-02-16

Pathogenesis of bisphosphonate-related osteonecrosis of the jaws (BRONJ) is not fully explained. An antiangiogenic effect of bisphosphonates (BPs) or an altered bone quality have been advocated. The aims of the present study were to analyze alveolar mandibular vascularization and bone quality in rats with BRONJ. Thirty-eight Sprague-Dawley rats were randomized into two groups: zoledronic acid (ZA), n = 27, and control (CTRL) n = 11. The ZA group received a weekly IV injection of ZA (100 μg/kg) during 10 weeks. The CTRL group received saline. After 6 weeks, extraction of the right mandibular molars was performed. Rats were sacrificed after 14 weeks. Microtomography characterized bone lesions and vascularization after injection of a radio-opaque material. Raman microspectroscopy evaluated bone mineralization. Fifty-five percent of ZA rats presented bone exposure and signs of BRONJ. None sign was found at the left hemimandible in the ZA group and in the CTRL group. Vascular density appeared significantly increased in the right hemimandibles of the CTRL group compared to the left hemimandibles. Vascularization was reduced in the ZA group. A significantly increased of the mineral-to-amide ratio was found in the alveolar bone of ZA rats by Raman microspectroscopy. In a rat model of BRONJ, microtomography evidenced osteonecrosis in BRONJ. Raman spectroscopy showed an increased mineralization. Vascularization after tooth extraction was impaired by ZA. Prolonged BP administration caused an increase in the mineralization and a quantitative reduction of the vascularization in the alveolar bone; both factors might be involved concomitantly in the BRONJ pathophysiology.

Orthodontically induced osteocyte apoptosis under different force magnitudes in rats: an immunohistochemical study.

PubMed

Kassem, Hassan E; Talaat, Iman M; El-Sawa, Afaf; Ismail, Hanan; Zaher, Abbas

2017-10-01

We investigated the effect of different force magnitudes on osteocyte apoptosis in a model of orthodontic tooth movement. Forty-nine male Sprague Dawley rats (7-9 wk of age) were divided into light- and heavy-force groups (n = 21 each group) and a control group (n = 7). A coil spring delivered pressure (either 10-15 g or 20-25 g) to the left maxillary first molar. The rats were sacrificed 1, 3, or 5 d after placement of the appliance. Sections of the maxillary first molars were immunostained for caspase-3. Upon force application, the number of apoptotic osteocytes significantly increased in the pressure side at 1 d and remained the same at 3 d and 5 d. However, there was no significant difference in the number of apoptotic osteocytes between the two force groups. We conclude that osteocyte apoptosis appears to increase under orthodontic loading, reaching a plateau after 1 d. However, osteocyte apoptosis seems to be independent of the magnitude of orthodontic forces tested. © 2017 Eur J Oral Sci.

Medication-related osteonecrosis of the jaw. Introduction of a new modified experimental model.

PubMed

Curra, Cláudia; Cardoso, Camila Lopes; Ferreira, Osny; Curi, Marcos Martins; Matsumoto, Mariza Akemi; Cavenago, Bruno Cavalini; Santos, Pâmela Letícia Dos; Santiago, Joel Ferreira

2016-05-01

To evaluate a modified experimental model for medication-related osteonecrosis of the jaw (MRONJ) through the upper right central incisor extraction followed by intravenous bisphosphonate administration. Forty five rats underwent the upper right central incisor tooth extraction were divided in 2 groups: Group I - experimental group, 30 rats received an intravenous administration protocol of zoledronic acid 35μg/kg into the tail vein every two weeks, totalizing four administrations, during eight weeks of administration, previously the extraction, and Group II - control group, 15 rats didn't received any medication before extraction. The groups were subdivided in postoperative periods: 14/28/42 days. Clinical analysis and microtomography were performed to verify the presence of osteonecrosis. In addition, descritive histological analysis of hematoxylin-eosin stained sections was performed to evaluate the presence of osteonecrosis or necrotic foci. Twelve (40%) rats, from experimental group, showed clinical signs of MRONJ (p=0.005), however, all samples showed imaginologic findings like osteolysis and loss of integrity of the cellular walls (p≤0.001). Microscopic evaluation revealed osteonecrosis areas with microbial colonies and inflammatory infiltrate (p≤0.001). In the control group, all animals presented the chronology of a normal wound healing. The presence of medication-related osteonecrosis of the jaw after maxillary central incisor extraction in rats. This new experimental model may be considered an option for the study of MRONJ.

Reactive oxygen species in the presence of high glucose alter ureteric bud morphogenesis.

PubMed

Zhang, Shao-Ling; Chen, Yun-Wen; Tran, Stella; Chenier, Isabelle; Hébert, Marie-Josée; Ingelfinger, Julie R

2007-07-01

Renal malformations are a major cause of childhood renal failure. During the development of the kidney, ureteric bud (UB) branching morphogenesis is critical for normal nephrogenesis. These studies investigated whether renal UB branching morphogenesis is altered by a high ambient glucose environment and studied underlying mechanism(s). Kidney explants that were isolated from different periods of gestation (embryonic days 12 to 18) from Hoxb7-green fluorescence protein mice were cultured for 24 h in either normal d-glucose (5 mM) or high d-glucose (25 mM) medium with or without various inhibitors. Alterations in renal morphogenesis were assessed by fluorescence microscopy. Paired-homeobox 2 (Pax-2) gene expression was determined by real-time quantitative PCR, Western blotting, and immunohistology. The results revealed that high d-glucose (25 mM) specifically stimulates UB branching morphogenesis via Pax-2 gene expression, whereas other glucose analogs, such as d-mannitol, l-glucose, and 2-deoxy-d-glucose, had no effect. The stimulatory effect of high glucose on UB branching was blocked in the presence of catalase and inhibitors of NADPH oxidase, mitochondrial electron transport chain complex I, and Akt signaling. Moreover, in in vivo studies, it seems that high glucose induces, via Pax-2 (mainly localized in UB), acceleration of UB branching but not nephron formation. Taken together, these data demonstrate that high glucose alters UB branching morphogenesis. This occurs, at least in part, via reactive oxygen species generation, activation of Akt signaling, and upregulation of Pax-2 gene expression.

A System for Modelling Cell–Cell Interactions during Plant Morphogenesis

PubMed Central

Dupuy, Lionel; Mackenzie, Jonathan; Rudge, Tim; Haseloff, Jim

2008-01-01

Background and aims During the development of multicellular organisms, cells are capable of interacting with each other through a range of biological and physical mechanisms. A description of these networks of cell–cell interactions is essential for an understanding of how cellular activity is co-ordinated in regionalized functional entities such as tissues or organs. The difficulty of experimenting on living tissues has been a major limitation to describing such systems, and computer modelling appears particularly helpful to characterize the behaviour of multicellular systems. The experimental difficulties inherent to the multitude of parallel interactions that underlie cellular morphogenesis have led to the need for computer models. Methods A new generic model of plant cellular morphogenesis is described that expresses interactions amongst cellular entities explicitly: the plant is described as a multi-scale structure, and interactions between distinct entities is established through a topological neighbourhood. Tissues are represented as 2D biphasic systems where the cell wall responds to turgor pressure through a viscous yielding of the cell wall. Key Results This principle was used in the development of the CellModeller software, a generic tool dedicated to the analysis and modelling of plant morphogenesis. The system was applied to three contrasting study cases illustrating genetic, hormonal and mechanical factors involved in plant morphogenesis. Conclusions Plant morphogenesis is fundamentally a cellular process and the CellModeller software, through its underlying generic model, provides an advanced research tool to analyse coupled physical and biological morphogenetic mechanisms. PMID:17921524

Synthesis and morphogenesis of organic and inorganic polymers by means of biominerals and biomimetic materials.

PubMed

Kijima, Misako; Oaki, Yuya; Munekawa, Yurika; Imai, Hiroaki

2013-02-11

We have studied the simultaneous synthesis and morphogenesis of polymer materials with hierarchical structures from nanoscopic to macroscopic scales. The morphologies of the original materials can be replicated to the polymer materials. In general, it is not easy to achieve the simultaneous synthesis and morphogenesis of polymer material even using host materials. In the present work, four biominerals and three biomimetic mesocrystal structures are used as the host materials or templates and polypyrrole, poly(3-hexylthiopehene), and silica were used as the precursors for the simultaneous syntheses and morphogenesis of polymer materials. The host materials with the hierarchical structure possess the nanospace for the incorporation of the monomers. After the incorporation of the monomers, the polymerization reaction proceeds in the nanospace with addition of the initiator agents. Then, the dissolution of the host materials leads to the formation and morphogenesis of the polymer materials. The scheme of the replication can be classified into the three types based on the structures of the host materials (types I-III). The type I template facilitates the hierarchical replication of the whole host material, type II mediates the hierarchical surface replication, and type III induces the formation of the two-dimensional nanosheets. Based on these results, the approach for the coupled synthesis and morphogenesis can be applied to a variety of combinations of the templates and polymer materials. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Periodontal Bioengineering: A Discourse in Surface Topographies, Progenitor Cells and Molecular Profiles

NASA Astrophysics Data System (ADS)

Dangaria, Smit J.

2011-12-01

Stem/progenitor cells are a population of cells capable of providing replacement cells for a given differentiated cell type. We have applied progenitor cell-based technologies to generate novel tissue-engineered implants that use biomimetic strategies with the ultimate goal of achieving full regeneration of lost periodontal tissues. Mesenchymal periodontal tissues such as cementum, alveolar bone (AB), and periodontal ligament (PDL) are neural crest-derived entities that emerge from the dental follicle (DF) at the onset of tooth root formation. Using a systems biology approach we have identified key differences between these periodontal progenitors on the basis of global gene expression profiles, gene cohort expression levels, and epigenetic modifications, in addition to differences in cellular morphologies. On an epigenetic level, DF progenitors featured high levels of the euchromatin marker H3K4me3, whereas PDL cells, AB osteoblasts, and cementoblasts contained high levels of the transcriptional repressor H3K9me3. Secondly, we have tested the influence of natural extracellular hydroxyapatite matrices on periodontal progenitor differentiation. Dimension and structure of extracellular matrix surfaces have powerful influences on cell shape, adhesion, and gene expression. Here we show that natural tooth root topographies induce integrin-mediated extracellular matrix signaling cascades in tandem with cell elongation and polarization to generate physiological periodontium-like tissues. In this study we replanted surface topography instructed periodontal ligament progenitors (PDLPs) into rat alveolar bone sockets for 8 and 16 weeks, resulting in complete attachment of tooth roots to the surrounding alveolar bone with a periodontal ligament fiber apparatus closely matching physiological controls along the entire root surface. Displacement studies and biochemical analyses confirmed that progenitor-based engineered periodontal tissues were similar to control teeth and uniquely derived from pre-implantation green fluorescent protein (GFP)-labeled progenitors. Together, these studies illustrate the capacity of natural extracellular surface topographies to instruct PDLPs to fully regenerate complex cellular and structural morphologies of tissues once lost to disease. We suggest that our strategy could be used for the replantation of teeth lost due to trauma or as a novel approach for tooth replacement using tooth-shaped replicas.

Eph/Ephrin signalling maintains eye field segregation from adjacent neural plate territories during forebrain morphogenesis

PubMed Central

Cavodeassi, Florencia; Ivanovitch, Kenzo; Wilson, Stephen W.

2013-01-01

During forebrain morphogenesis, there is extensive reorganisation of the cells destined to form the eyes, telencephalon and diencephalon. Little is known about the molecular mechanisms that regulate region-specific behaviours and that maintain the coherence of cell populations undergoing specific morphogenetic processes. In this study, we show that the activity of the Eph/Ephrin signalling pathway maintains segregation between the prospective eyes and adjacent regions of the anterior neural plate during the early stages of forebrain morphogenesis in zebrafish. Several Ephrins and Ephs are expressed in complementary domains in the prospective forebrain and combinatorial abrogation of their activity results in incomplete segregation of the eyes and telencephalon and in defective evagination of the optic vesicles. Conversely, expression of exogenous Ephs or Ephrins in regions of the prospective forebrain where they are not usually expressed changes the adhesion properties of the cells, resulting in segregation to the wrong domain without changing their regional fate. The failure of eye morphogenesis in rx3 mutants is accompanied by a loss of complementary expression of Ephs and Ephrins, suggesting that this pathway is activated downstream of the regional fate specification machinery to establish boundaries between domains undergoing different programmes of morphogenesis. PMID:24026122

Ultrastructural visualisation of proteoglycans in early unmineralised dentine of rat tooth germs stained with cuprolinic blue.

PubMed Central

Tenorio, D; Reid, A R; Katchburian, E

1990-01-01

The ultrastructural distribution and localisation of proteoglycans (PGs) of early developing rat dentine were examined using cuprolinic blue in a critical electrolyte concentration procedure. Results show that the cuprolinic blue method produces images of higher morphological quality than other cationic dyes. PGs appeared as ribbon-like electron-opaque precipitates of various sizes, ranging between 1.4 and 0.2 microns in length, distributed throughout the matrix and in close association with well preserved matrix vesicles and collagen fibrils. Matrix vesicles revealed tightly packed PG filaments which appeared to be attached to their membrane. It is possible that the close association of PG filaments with matrix vesicles and collagen indicates that PGs are related to the process of mineralisation of dentine. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 PMID:2384338

Streptococcus mutans in a Wild, Sucrose-Eating Rat Population

PubMed Central

Coykendall, Alan L.; Specht, Patricia A.; Samol, Harry H.

1974-01-01

Streptococcus mutans, an organism implicated in dental caries and not previously found outside of man and certain laboratory animals, was isolated from the mouths of wild rats which ate sugar cane. The strains isolated fermented mannitol and sorbitol, and failed to grow in 6.5% NaCl or at 45 C. They formed in vitro plaques on nichrome wires when grown in sucrose broth. They also stored intracellular polysaccharide which could be catabolized by washed, resting cells. Deoxyribonucleic acid-deoxyribonucleic acid reassociations revealed two genetic types. One type shared extensive deoxyribonucleic acid base sequences with S. mutans strains HS6 and OMZ61, two members of a genetic type found in man and laboratory hamsters. The other type seemed unrelated to any S. mutans genetic type previously encountered. It is concluded that the ecological triad of tooth-sucrose-S. mutans is not a phenomenon unique to man and experimental animals. Images PMID:4601769

Evaluation of the topical effect of alendronate on the root surface of extracted and replanted teeth. Microscopic analysis on rats' teeth.

PubMed

Lustosa-Pereira, Adriana; Garcia, Roberto Brandão; de Moraes, Ivaldo Gomes; Bernardineli, Norberti; Bramante, Clovis Monteiro; Bortoluzzi, Eduardo Antunes

2006-02-01

The treatment of choice for tooth avulsion is replantation. The ideal replantation should be realized as quickly as possible, or at least, the avulsed tooth should be kept in an adequate solution to preserve the periodontal ligament attached to the root. If that is not possible, treatment of the radicular surface should be done in order to prevent radicular resorption. The purpose of this study was to test sodium alendronate as a substance for topical treatment of the radicular surface of avulsed teeth in an attempt to prevent the occurrence of dental resorptions. Fifty-four rat maxillary right central incisors were extracted and replanted. Group I--extra-alveolar dry period of 15 min, intracanal dressing with calcium hydroxide (CALEN, S.S. White, Artigos Dentários LTDA, Rio de Janeiro, Brazil) and replantation; Groups II and III - extra-alveolar dry periods of 30 and 60 min, respectively, immersion in 1% sodium hypochlorite for 30 min for removal of the periodontal ligament, washing in saline solution for 5 min, and treatment of the radicular surface with 3.2 mg/l sodium alendronate solution for 10 min. Intracanal dressing with calcium hydroxide and replantation followed. At 15, 60, and 90 days post-reimplantation, the animals were killed and the samples obtained and processed for microscopic analysis. The results indicated that sodium alendronate was able to reduce the incidence of radicular resorption, but not of dental ankylosis. No significant differences were observed regarding variations in the extra-alveolar periods among the groups.

The control of branching morphogenesis

PubMed Central

Iber, Dagmar; Menshykau, Denis

2013-01-01

Many organs of higher organisms are heavily branched structures and arise by an apparently similar process of branching morphogenesis. Yet the regulatory components and local interactions that have been identified differ greatly in these organs. It is an open question whether the regulatory processes work according to a common principle and how far physical and geometrical constraints determine the branching process. Here, we review the known regulatory factors and physical constraints in lung, kidney, pancreas, prostate, mammary gland and salivary gland branching morphogenesis, and describe the models that have been formulated to analyse their impacts. PMID:24004663

Programming Morphogenesis through Systems and Synthetic Biology.

PubMed

Velazquez, Jeremy J; Su, Emily; Cahan, Patrick; Ebrahimkhani, Mo R

2018-04-01

Mammalian tissue development is an intricate, spatiotemporal process of self-organization that emerges from gene regulatory networks of differentiating stem cells. A major goal in stem cell biology is to gain a sufficient understanding of gene regulatory networks and cell-cell interactions to enable the reliable and robust engineering of morphogenesis. Here, we review advances in synthetic biology, single cell genomics, and multiscale modeling, which, when synthesized, provide a framework to achieve the ambitious goal of programming morphogenesis in complex tissues and organoids. Copyright © 2017 Elsevier Ltd. All rights reserved.

Remodeling a tissue: subtraction adds insight.

PubMed

Axelrod, Jeffrey D

2012-11-27

Sculpting a body plan requires both patterning of gene expression and translating that pattern into morphogenesis. Developmental biologists have made remarkable strides in understanding gene expression patterning, but despite a long history of fascination with the mechanics of morphogenesis, knowledge of how patterned gene expression drives the emergence of even simple shapes and forms has grown at a slower pace. The successful merging of approaches from cell biology, developmental biology, imaging, engineering, and mathematical and computational sciences is now accelerating progress toward a fuller and better integrated understanding of the forces shaping morphogenesis.

Canonical TGF-β Signaling Negatively Regulates Neuronal Morphogenesis through TGIF/Smad Complex-Mediated CRMP2 Suppression.

PubMed

Nakashima, Hideyuki; Tsujimura, Keita; Irie, Koichiro; Ishizu, Masataka; Pan, Miao; Kameda, Tomonori; Nakashima, Kinichi

2018-05-16

Functional neuronal connectivity requires proper neuronal morphogenesis and its dysregulation causes neurodevelopmental diseases. Transforming growth factor-β (TGF-β) family cytokines play pivotal roles in development, but little is known about their contribution to morphological development of neurons. Here we show that the Smad-dependent canonical signaling of TGF-β family cytokines negatively regulates neuronal morphogenesis during brain development. Mechanistically, activated Smads form a complex with transcriptional repressor TG-interacting factor (TGIF), and downregulate the expression of a neuronal polarity regulator, collapsin response mediator protein 2. We also demonstrate that TGF-β family signaling inhibits neurite elongation of human induced pluripotent stem cell-derived neurons. Furthermore, the expression of TGF-β receptor 1, Smad4, or TGIF, which have mutations found in patients with neurodevelopmental disorders, disrupted neuronal morphogenesis in both mouse (male and female) and human (female) neurons. Together, these findings suggest that the regulation of neuronal morphogenesis by an evolutionarily conserved function of TGF-β signaling is involved in the pathogenesis of neurodevelopmental diseases. SIGNIFICANCE STATEMENT Canonical transforming growth factor-β (TGF-β) signaling plays a crucial role in multiple organ development, including brain, and mutations in components of the signaling pathway associated with several human developmental disorders. In this study, we found that Smads/TG-interacting factor-dependent canonical TGF-β signaling regulates neuronal morphogenesis through the suppression of collapsin response mediator protein-2 (CRMP2) expression during brain development, and that function of this signaling is evolutionarily conserved in the mammalian brain. Mutations in canonical TGF-β signaling factors identified in patients with neurodevelopmental disorders disrupt the morphological development of neurons. Thus, our results suggest that proper control of TGF-β/Smads/CRMP2 signaling pathways is critical for the precise execution of neuronal morphogenesis, whose impairment eventually results in neurodevelopmental disorders. Copyright © 2018 the authors 0270-6474/18/384791-20$15.00/0.

[Husbandry appropriate to the species for African naked mole rats (Heterocephalus glaber)].

PubMed

Petry, H

2003-12-01

It is reported about the keeping of a group of Naked Mole Rats (Heterocephalus glaber; nine males and 13 females), which had been imported from Kenya in 1996. The animals are kept in a small experimental room without windows at permanent darkness, 30 degrees C environmental temperature and relative humidity above 70%. They live in a glass container, to which a collapsible system of plexiglass tubes is connected. The moles are daily fed ad libitum with different fresh root crops. Until today three adult animals of the colony have died (tooth problems; bite injuries; parturition complication). The first queen of the colony had three litters with altogether 10 puppies, of which four are still alive. It died during its last litter caused by a complicated stillbirth. The female established after that as new queen in the colony had up to now only one litter with two puppies, which did not survive. The evaluation of the motor activity of the naked mole rats - continously recorded by video techniques - showed the period length of their circadian activity rhythm on the average with 24 h 13.5 +/- 14.4 min. It is supposed that the activity of the mole rats is regulated by the alteration of the local earth magnet field running in a 24-h rhythm.

Perithecium morphogenesis in Sordaria macrospora.

PubMed

Lord, Kathryn M; Read, Nick D

2011-04-01

The perithecium of the self-fertile ascomycete Sordaria macrospora provides an excellent model in which to analyse fungal multicellular development. This study provides a detailed analysis of perithecium morphogenesis in the wild type and eight developmental mutants of S. macrospora, using a range of correlative microscopical techniques. Fundamentally, perithecia and other complex multicellular structures produced by fungi arise by hyphal aggregation and adhesion, and these processes are followed by specialization and septation of hyphal compartments within the aggregates. Perithecial morphogenesis can be divided into the ascogonial, protoperithecial, and perithecial stages of development. At least 13 specialized, morphologically distinct cell-types are involved in perithecium morphogenesis, and these fall into three basic classes: hyphae, conglutinate cells and spores. Conglutinate cells arise from hyphal adhesion and certain perithecial hyphae develop from conglutinate cells. Various hypha-conglutinate cell transitions play important roles during the development of the perithecial wall and neck. Copyright © 2010. Published by Elsevier Inc.

The ureteric bud epithelium: morphogenesis and roles in metanephric kidney patterning.

PubMed

Nagalakshmi, Vidya K; Yu, Jing

2015-03-01

The mammalian metanephric kidney is composed of two epithelial components, the collecting duct system and the nephron epithelium, that differentiate from two different tissues -the ureteric bud epithelium and the nephron progenitors, respectively-of intermediate mesoderm origin. The collecting duct system is generated through reiterative ureteric bud branching morphogenesis, whereas the nephron epithelium is formed in a process termed nephrogenesis, which is initiated with the mesenchymal-epithelial transition of the nephron progenitors. Ureteric bud branching morphogenesis is regulated by nephron progenitors, and in return, the ureteric bud epithelium regulates nephrogenesis. The metanephric kidney is physiologically divided along the corticomedullary axis into subcompartments that are enriched with specific segments of these two epithelial structures. Here, we provide an overview of the major molecular and cellular processes underlying the morphogenesis and patterning of the ureteric bud epithelium and its roles in the cortico-medullary patterning of the metanephric kidney. © 2015 Wiley Periodicals, Inc.

Bis-enoxacin Inhibits Bone Resorption and Orthodontic Tooth Movement

PubMed Central

Toro, E.J.; Zuo, J.; Guiterrez, A.; La Rosa, R.L.; Gawron, A.J.; Bradaschia-Correa, V.; Arana-Chavez, V.; Dolce, C.; Rivera, M.F.; Kesavalu, L.; Bhattacharyya, I.; Neubert, J.K.; Holliday, L.S.

2013-01-01

Enoxacin inhibits binding between the B-subunit of vacuolar H+-ATPase (V-ATPase) and microfilaments, and also between osteoclast formation and bone resorption in vitro. We hypothesized that a bisphosphonate derivative of enoxacin, bis-enoxacin (BE), which was previously studied as a bone-directed antibiotic, might have similar activities. BE shared a number of characteristics with enoxacin: It blocked binding between the recombinant B-subunit and microfilaments and inhibited osteoclastogenesis in cell culture with IC50s of about 10 µM in each case. BE did not alter the relative expression levels of various osteoclast-specific proteins. Even though tartrate-resistant acid phosphatase 5b was expressed, proteolytic activation of the latent pro-enzyme was inhibited. However, unlike enoxacin, BE stimulated caspase-3 activity. BE bound to bone slices and inhibited bone resorption by osteoclasts on BE-coated bone slices in cell culture. BE reduced the amount of orthodontic tooth movement achieved in rats after 28 days. Analysis of these data suggests that BE is a novel anti-resorptive molecule that is active both in vitro and in vivo and may have clinical uses. Abbreviations: BE, bis-enoxacin; V-ATPase, vacuolar H+-ATPase; TRAP, tartrate-resistant acid phosphatase; αMEM D10, minimal essential media, alpha modification with 10% fetal bovine serum; SDS-PAGE, sodium dodecyl sulfate-polyacrylamide gel electrophoresis; RANKL, receptor activator of nuclear factor kappa B-ligand; NFATc1, nuclear factor of activated T-cells; ADAM, a disintegrin and metalloprotease domain; OTM, orthodontic tooth movement. PMID:23958763

Effectiveness of anchovy substrate application on decreasing acid solubility of Sprague Dawley rats’ tooth enamel (in vivo)

NASA Astrophysics Data System (ADS)

Triputra, F.; Puspitawati, R.; Gunawan, H. A.

2017-08-01

Anchovies (Stolephorus insularis), a natural resource of Indonesia, contain fluoride in the form of CaF2 and can function as a fluoridation material to prevent dental caries. The aim of this study is to study the effectiveness of anchovy substrate, through food or topical application, in decreasing the acid solubility of tooth enamel. This research used 14 Sprague Dawley rats as subjects divided into the following 5 groups: baseline, experimental feeding, experimental smearing, and their negative controls. After 15 days of anchovy substrate application, lower incisors were extracted and the acid solubility of enamel was analyzed qualitatively and quantitatively using a stereo microscope and a Micro-Vickers Hardness Tester. Analysis of enamel surface destruction and enamel surface microscopic hardness shifting after a 60 sec application of H2PO4 (50% concentration) resulted in a decrease in acid solubility of enamel treated with anchovy substrate. This result can be seen with both the chewing and smearing method. S. insularis can be used as an alternative material for fluoridation.

In utero and lactational exposure to low-dose genistein-vinclozolin mixture affects the development and growth factor mRNA expression of the submandibular salivary gland in immature female rats.

PubMed

Kouidhi, Wided; Desmetz, Catherine; Nahdi, Afef; Bergès, Raymond; Cravedi, Jean-Pierre; Auger, Jacques; El May, Michèle; Canivenc-Lavier, Marie Chantal

2012-06-01

It has been suggested that hormonally controlled submandibular salivary gland (SSG) development and secretions may be affected by endocrine disruptor compounds. We investigated the effects of oral gestation-lactation exposure to 1 mg/kg body weight daily dose of the estrogenic soy-isoflavone genistein and/or the anti-androgenic food contaminant vinclozolin in female rats. The SSGs of female offspring were collected at postnatal day 35 to study gland morphogenesis and mRNA expression of sex-hormone receptors and endocrine growth factors as sex-dependent biomarkers. Because of high expression in neonatal SSG, mRNA expression of transforming growth factor α was also studied. Exposure to genistein, vinclozolin, or a genistein+vinclozolin mixture resulted in significantly lower numbers of striated ducts linked to an increase in their area and lower acinar proliferation (Ki-67-positive nuclei). Exposure to the mixture had the highest significant effects, which were particularly associated with repression of epidermal growth factor, nerve growth factor, and transforming growth factor α expression. In conclusion, early exposure to low doses of genistein and vinclozolin can affect glandular structure and endocrine gene mRNA expression in prepubertal SSG in female rats, and the effects are potentialized by the genistein+vinclozolin mixture. Our study provides the first evidence that SSG are targeted by both estrogenic and anti-androgenic disrupting compounds and are more sensitive to mixtures.

Human Development VI: Supracellular Morphogenesis. The Origin of Biological and Cellular Order

PubMed Central

Ventegodt, Søren; Hermansen, Tyge Dahl; Flensborg-Madsen, Trine; Nielsen, Maj Lyck; Merrick, Joav

2006-01-01

Uninterrupted morphogenesis shows the informational potentials of biological organisms. Experimentally disturbed morphogenesis shows the compensational dynamics of the biological informational system, which is the rich informational redundancy. In this paper, we use these data to describe morphogenesis in terms of the development of supracellular levels of the organism, and we define complex epigenesis and supracellular differentiation. We review the phenomena of regeneration and induction of Hydra and amphibians, and the higher animals informational needs for developing their complex nervous systems. We argue, also building on the NO-GO theorem for ontogenesis as chemistry, that the traditional chemical explanations of high-level informational events in ontogenesis, such as transmutation, regeneration, and induction, are insufficient. We analyze the informational dynamics of three embryonic compensatory reactions to different types of disturbances: (1) transmutations of the imaginal discs of insects, (2) regeneration after removal of embryonic tissue, and (3) embryonic induction, where two tissues that normally are separated experimentally are made to influence each other. We describe morphogenesis as a complex bifurcation, and the resulting morphological levels of the organism as organized in a fractal manner and supported by positional information. We suggest that some kind of real nonchemical phenomenon must be taking form in living organisms as an information-carrying dynamic fractal field, causing morhogenesis and supporting the organisms morphology through time. We argue that only such a phenomenon that provides information-directed self-organization to the organism is able to explain the observed dynamic distribution of biological information through morphogenesis and the organism's ability to rejuvenate and heal. PMID:17115082

Direct activation of Shroom3 transcription by Pitx proteins drives epithelial morphogenesis in the developing gut

PubMed Central

Chung, Mei-I; Nascone-Yoder, Nanette M.; Grover, Stephanie A.; Drysdale, Thomas A.; Wallingford, John B.

2010-01-01

Individual cell shape changes are essential for epithelial morphogenesis. A transcriptional network for epithelial cell shape change is emerging in Drosophila, but this area remains largely unexplored in vertebrates. The distinction is important as so far, key downstream effectors of cell shape change in Drosophila appear not to be conserved. Rather, Shroom3 has emerged as a central effector of epithelial morphogenesis in vertebrates, driving both actin- and microtubule-based cell shape changes. To date, the morphogenetic role of Shroom3 has been explored only in the neural epithelium, so the broad expression of this gene raises two important questions: what are the requirements for Shroom3 in non-neural tissues and what factors control Shroom3 transcription? Here, we show in Xenopus that Shroom3 is essential for cell shape changes and morphogenesis in the developing vertebrate gut and that Shroom3 transcription in the gut requires the Pitx1 transcription factor. Moreover, we show that Pitx proteins directly activate Shroom3 transcription, and we identify Pitx-responsive regulatory elements in the genomic DNA upstream of Shroom3. Finally, we show that ectopic expression of Pitx proteins is sufficient to induce Shroom3-dependent cytoskeletal reorganization and epithelial cell shape change. These data demonstrate new breadth to the requirements for Shroom3 in morphogenesis, and they also provide a cell-biological basis for the role of Pitx transcription factors in morphogenesis. More generally, these results provide a foundation for deciphering the transcriptional network that underlies epithelial cell shape change in developing vertebrates. PMID:20332151

Fibronectin Deposition Participates in Extracellular Matrix Assembly and Vascular Morphogenesis

PubMed Central

Hielscher, Abigail; Ellis, Kim; Qiu, Connie; Porterfield, Josh; Gerecht, Sharon

2016-01-01

The extracellular matrix (ECM) has been demonstrated to facilitate angiogenesis. In particular, fibronectin has been documented to activate endothelial cells, resulting in their transition from a quiescent state to an active state in which the cells exhibit enhanced migration and proliferation. The goal of this study is to examine the role of polymerized fibronectin during vascular tubulogenesis using a 3 dimensional (3D) cell-derived de-cellularized matrix. A fibronectin-rich 3D de-cellularized ECM was used as a scaffold to study vascular morphogenesis of endothelial cells (ECs). Confocal analyses of several matrix proteins reveal high intra- and extra-cellular deposition of fibronectin in formed vascular structures. Using a small peptide inhibitor of fibronectin polymerization, we demonstrate that inhibition of fibronectin fibrillogenesis in ECs cultured atop de-cellularized ECM resulted in decreased vascular morphogenesis. Further, immunofluorescence and ultrastructural analyses reveal decreased expression of stromal matrix proteins in the absence of polymerized fibronectin with high co-localization of matrix proteins found in association with polymerized fibronectin. Evaluating vascular kinetics, live cell imaging showed that migration, migration velocity, and mean square displacement, are disrupted in structures grown in the absence of polymerized fibronectin. Additionally, vascular organization failed to occur in the absence of a polymerized fibronectin matrix. Consistent with these observations, we tested vascular morphogenesis following the disruption of EC adhesion to polymerized fibronectin, demonstrating that block of integrins α5β1 and αvβ3, abrogated vascular morphogenesis. Overall, fibronectin deposition in a 3D cell-derived de-cellularized ECM appears to be imperative for matrix assembly and vascular morphogenesis. PMID:26811931

Arp2/3 and VASP Are Essential for Fear Memory Formation in Lateral Amygdala.

PubMed

Basu, Sreetama; Kustanovich, Irina; Lamprecht, Raphael

2016-01-01

The actin cytoskeleton is involved in key neuronal functions such as synaptic transmission and morphogenesis. However, the roles and regulation of actin cytoskeleton in memory formation remain to be clarified. In this study, we unveil the mechanism whereby actin cytoskeleton is regulated to form memory by exploring the roles of the major actin-regulatory proteins Arp2/3, VASP, and formins in long-term memory formation. Inhibition of Arp2/3, involved in actin filament branching and neuronal morphogenesis, in lateral amygdala (LA) with the specific inhibitor CK-666 during fear conditioning impaired long-term, but not short-term, fear memory. The inactive isomer CK-689 had no effect on memory formation. We observed that Arp2/3 is colocalized with the actin-regulatory protein profilin in LA neurons of fear-conditioned rats. VASP binding to profilin is needed for profilin-mediated stabilization of actin cytoskeleton and dendritic spine morphology. Microinjection of poly-proline peptide [G(GP 5 ) 3 ] into LA, to interfere with VASP binding to profilin, impaired long-term but not short-term fear memory formation. Control peptide [G(GA 5 ) 3 ] had no effect. Inhibiting formins, which regulate linear actin elongation, in LA during fear conditioning by microinjecting the formin-specific inhibitor SMIFH2 into LA had no effect on long-term fear memory formation. We conclude that Arp2/3 and VASP, through the profilin binding site, are essential for the formation of long-term fear memory in LA and propose a model whereby these proteins subserve cellular events, leading to memory consolidation.

Dlx homeobox gene family expression in osteoclasts.

PubMed

Lézot, F; Thomas, B L; Blin-Wakkach, C; Castaneda, B; Bolanos, A; Hotton, D; Sharpe, P T; Heymann, D; Carles, G F; Grigoriadis, A E; Berdal, A

2010-06-01

Skeletal growth and homeostasis require the finely orchestrated secretion of mineralized tissue matrices by highly specialized cells, balanced with their degradation by osteoclasts. Time- and site-specific expression of Dlx and Msx homeobox genes in the cells secreting these matrices have been identified as important elements in the regulation of skeletal morphology. Such specific expression patterns have also been reported in osteoclasts for Msx genes. The aim of the present study was to establish the expression patterns of Dlx genes in osteoclasts and identify their function in regulating skeletal morphology. The expression patterns of all Dlx genes were examined during the whole osteoclastogenesis using different in vitro models. The results revealed that Dlx1 and Dlx2 are the only Dlx family members with a possible function in osteoclastogenesis as well as in mature osteoclasts. Dlx5 and Dlx6 were detected in the cultures but appear to be markers of monocytes and their derivatives. In vivo, Dlx2 expression in osteoclasts was examined using a Dlx2/LacZ transgenic mouse. Dlx2 is expressed in a subpopulation of osteoclasts in association with tooth, brain, nerve, and bone marrow volumetric growths. Altogether the present data suggest a role for Dlx2 in regulation of skeletal morphogenesis via functions within osteoclasts. (c) 2010 Wiley-Liss, Inc.

Multicellular Models of Morphogenesis

EPA Science Inventory

EPA’s Virtual Embryo project (v-Embryo™), in collaboration with developers of CompuCell3D, aims to create computer models of morphogenesis that can be used to address the effects of chemical perturbation on embryo development at the cellular level. Such computational (in silico) ...

Morphogenesis in Plants: Modeling the Shoot Apical Meristem, and Possible Applications

NASA Technical Reports Server (NTRS)

Mjolsness, Eric; Gor, Victoria; Meyerowitz, Elliot; Mann, Tobias

1998-01-01

A key determinant of overall morphogenesis in flowering plants such as Arabidopsis thaliana is the shoot apical meristem (growing tip of a shoot). Gene regulation networks can be used to model this system. We exhibit a very preliminary two-dimensional model including gene regulation and intercellular signaling, but omitting cell division and dynamical geometry. The model can be trained to have three stable regions of gene expression corresponding to the central zone, peripheral zone, and rib meristem. We also discuss a space-engineering motivation for studying and controlling the morphogenesis of plants using such computational models.

The Ron Receptor Tyrosine Kinase Negatively Regulates Mammary Gland Branching Morphogenesis

PubMed Central

Meyer, Sara E.; Zinser, Glendon M.; Stuart, William D.; Pathrose, Peterson; Waltz, Susan E.

2009-01-01

The Ron receptor tyrosine kinase is expressed in normal breast tissue and is overexpressed in approximately 50% of human breast cancers. Despite the recent studies on Ron in breast cancer, nothing is known about the importance of this protein during breast development. To investigate the functional significance of Ron in the normal mammary gland, we compared mammary gland development in wild-type mice to mice containing a targeted ablation of the tyrosine kinase (TK) signaling domain of Ron (TK−/−). Mammary glands from RonTK−/− mice exhibited accelerated pubertal development including significantly increased ductal extension and branching morphogenesis. While circulating levels of estrogen, progesterone, and overall rates of epithelial cell turnover were unchanged, significant increases in phosphorylated MAPK, which predominantly localized to the epithelium, were associated with increased branching morphogenesis. Additionally, purified RonTK−/− epithelial cells cultured ex vivo exhibited enhanced branching morphogenesis, which was reduced upon MAPK inhibition. Microarray analysis of pubertal RonTK−/− glands revealed 393 genes temporally impacted by Ron expression with significant changes observed in signaling networks regulating development, morphogenesis, differentiation, cell motility, and adhesion. In total, these studies represent the first evidence of a role for the Ron receptor tyrosine kinase as a critical negative regulator of mammary development. PMID:19576199

Evaluation of an experimental rat model for comparative studies of bleaching agents.

PubMed

Cintra, Luciano Tavares Angelo; Benetti, Francine; Ferreira, Luciana Louzada; Rahal, Vanessa; Ervolino, Edilson; Jacinto, Rogério de Castilho; Gomes Filho, João Eduardo; Briso, André Luiz Fraga

2016-04-01

Dental materials in general are tested in different animal models prior to the clinical use in humans, except for bleaching agents. Objectives To evaluate an experimental rat model for comparative studies of bleaching agents, by investigating the influence of different concentrations and application times of H2O2 gel in the pulp tissue during in-office bleaching of rats' vital teeth. Material and Methods The right and left maxillary molars of 50 Wistar rats were bleached with 20% and 35% H2O2 gels, respectively, for 5, 10, 15, 30, or 45 min (n=10 rats/group). Ten animals were untreated (control). The rats were killed after 2 or 30 days, and the maxillae were examined by light microscopy. Inflammation was evaluated through histomorphometric analysis with inflammatory cell count in the coronal and radicular thirds of the pulp. Fibroblasts were also counted. Scores were attributed to odontoblastic layer and vascular changes. Tertiary dentin area and pulp chamber central area were measured histomorphometrically. Data were compared by analysis of variance and Kruskal-Wallis test (p<0.05). Results After 2 days, the amount of inflammatory cells increased in the coronal pulp occlusal third up to the 15-min application groups of each bleaching gel. In the groups exposed to each concentration for 30 and 45 min, the number of inflammatory cells decreased along with the appearance of necrotic areas. After 30 days, reduction on the pulp chamber central area and enlargement of the tertiary dentin area were observed, without the detection of inflammation areas. Conclusion The rat model of extracoronal bleaching showed to be adequate for studies of bleaching protocols, as it was possible to observe alterations in the pulp tissues and tooth structure caused by different concentrations and application periods of bleaching agents.

Histomorphometric study of alveolar bone healing in rats fed a boron-deficient diet.

PubMed

Gorustovich, Alejandro A; Steimetz, Tammy; Nielsen, Forrest H; Guglielmotti, María B

2008-04-01

Bone healing after tooth extraction in rats is a suitable experimental model to study bone formation. Thus, we performed a study to determine the effects of boron (B) deficiency on bone healing by using this model. The first lower right molar of weanling Wistar rats was extracted under anesthesia. The animals were divided into two groups: +B (adequate; 3 mg B/kg diet), and -B (boron-deficient; 0.07 mg/kg diet). The animals in both groups were killed in groups of 10 at 7 and 14 days after surgery. The guidelines of the NIH for the care and use of laboratory animals were observed. The mandibles were resected, fixed, decalcified, and embedded in paraffin. Buccolingually oriented sections were obtained at the level of the mesial alveolus and used for histometric evaluations. Total alveolar volume (TAV) and trabecular bone volume per total volume (BV/TV) in the apical third of the alveolus were determined. Percentages of osteoblast surface (ObS), eroded surface (ES), and quiescent surface (QS) were determined. No statistical significant differences in food intake and body weight were observed. Histomorphometric evaluation found -B rats had 36% and 63% reductions in BV/TV at 7 and 14 days, respectively. When compared with +B rats, -B rats had significant reductions (57% and 87%) in ObS concomitantly with increases (120% and 126%) in QS at 7 and 14 days, respectively. The findings show that boron deficiency results in altered bone healing because of a marked reduction in osteogenesis. 2008 Wiley-Liss, Inc

Histomorphometric study of the periodontal ligament in the initial period of orthodontic movement in Wistar rats with induced allergic asthma.

PubMed

Machado, Cristiane Correia Pereira; Nojima, Matilde da Cunha Gonçalves; Rodrigues e Silva, Patrícia Machado; Mandarim-de-Lacerda, Carlos Alberto

2012-09-01

Asthma is a common systemic disease occurring in infancy and adolescence, time periods that could encompass orthodontic treatment. Asthma is an inflammatory disease; therefore, it might interfere with orthodontic tooth movement. The purpose of the study was to analyze the histomorphologic aspects of the periodontal ligament of asthmatic Wistar rats in the initial period of orthodontic movement. Thirty-two Wistar rats were divided into 4 groups: 2 control groups consisting of rats without induced allergic asthma, and 2 experimental groups consisting of rats with induced allergic asthma. The animals of the first control and experimental groups did not receive orthodontic forces, whereas those in the second control and experimental groups were subjected to mesial movement of the maxillary left first molar for 3 days. The samples were prepared for histomorphometric analysis of the periodontal ligament. The area of the periodontal ligament was calculated as a function of root length in the cervical and apical regions of the distal face of the maxillary first molar mesial root. The Student t test and the Welch correlation test were applied to the data obtained. There was a statistically significant difference (P <0.05) between the control and experimental groups. An enhanced response to orthodontic force was observed in the asthmatic animals: the periodontal ligament was more compressed at the pressure area and more stretched in the traction area. Our findings indicate that experimental allergic asthma seems to exacerbate orthodontic movement in rats. Copyright © 2012 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Could zoledronic acid prevent root resorption in replanted rat molar?

PubMed

Yoo, Jung Eun; Kim, Mi Sun; Kwon, Yong-Dae; Kim, Eun-Cheol; Kim, Kwang Chul; Choi, Sung Chul

2015-12-01

In this study, we evaluated whether zoledronate could suppress the progression of external root resorption in rat due to delayed replantation by inhibiting osteoclastic activity. Also, we estimated the optimal dosage of zoledronate in root treatment of the rat model for a maximum effect of zoledronate. Maxillary first molars in Sprague Dawley rats (N = 84) were extracted, dried for 60 min, and then replanted. The rats were divided into 6 groups (1 mM alendronate, and 1, 5, 10, 20, 40 μM zoledronate). At 4 and 8 weeks postreplantation, the animals were sacrificed and evaluated by radiographic and histological analysis. There were no significant differences at 4 weeks. However, at 8 weeks, 10, 20, and 40 μM ZOL showed more increased radiopaque and smaller periapical lesion in radiographic analysis. In histological analysis, all groups showed similar inflammatory root resorption rate at 4 weeks. However, at 8 weeks, 20 and 40 μM ZOL showed lower rate than those of other groups (P < 0.05). In concerning of replacement resorption, there were no significant differences statistically. In this animal experiment, zoledronate was capable of limiting the occurrence of root resorption in delayed replantation model. In particular, 20 μM dosage of zoledronate solution showed the most effective dose in long-term follow up and might be suitable for inhibition of root resorption in delayed tooth replantation. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Adenosine kinase modulates root gravitropism and cap morphogenesis in Arabidopsis.

PubMed

Young, Li-Sen; Harrison, Benjamin R; Narayana Murthy, U M; Moffatt, Barbara A; Gilroy, Simon; Masson, Patrick H

2006-10-01

Adenosine kinase (ADK) is a key enzyme that regulates intra- and extracellular levels of adenosine, thereby modulating methyltransferase reactions, production of polyamines and secondary compounds, and cell signaling in animals. Unfortunately, little is known about ADK's contribution to the regulation of plant growth and development. Here, we show that ADK is a modulator of root cap morphogenesis and gravitropism. Upon gravistimulation, soluble ADK levels and activity increase in the root tip. Mutation in one of two Arabidopsis (Arabidopsis thaliana) ADK genes, ADK1, results in cap morphogenesis defects, along with alterations in root sensitivity to gravistimulation and slower kinetics of root gravitropic curvature. The kinetics defect can be partially rescued by adding spermine to the growth medium, whereas the defects in cap morphogenesis and gravitropic sensitivity cannot. The root morphogenesis and gravitropism defects of adk1-1 are accompanied by altered expression of the PIN3 auxin efflux facilitator in the cap and decreased expression of the auxin-responsive DR5-GUS reporter. Furthermore, PIN3 fails to relocalize to the bottom membrane of statocytes upon gravistimulation. Consequently, adk1-1 roots cannot develop a lateral auxin gradient across the cap, necessary for the curvature response. Interestingly, adk1-1 does not affect gravity-induced cytoplasmic alkalinization of the root statocytes, suggesting either that ADK1 functions between cytoplasmic alkalinization and PIN3 relocalization in a linear pathway or that the pH and PIN3-relocalization responses to gravistimulation belong to distinct branches of the pathway. Our data are consistent with a role for ADK and the S-adenosyl-L-methionine pathway in the control of root gravitropism and cap morphogenesis.

Adenosine Kinase Modulates Root Gravitropism and Cap Morphogenesis in Arabidopsis1[W][OA

PubMed Central

Young, Li-Sen; Harrison, Benjamin R.; U.M., Narayana Murthy; Moffatt, Barbara A.; Gilroy, Simon; Masson, Patrick H.

2006-01-01

Adenosine kinase (ADK) is a key enzyme that regulates intra- and extracellular levels of adenosine, thereby modulating methyltransferase reactions, production of polyamines and secondary compounds, and cell signaling in animals. Unfortunately, little is known about ADK's contribution to the regulation of plant growth and development. Here, we show that ADK is a modulator of root cap morphogenesis and gravitropism. Upon gravistimulation, soluble ADK levels and activity increase in the root tip. Mutation in one of two Arabidopsis (Arabidopsis thaliana) ADK genes, ADK1, results in cap morphogenesis defects, along with alterations in root sensitivity to gravistimulation and slower kinetics of root gravitropic curvature. The kinetics defect can be partially rescued by adding spermine to the growth medium, whereas the defects in cap morphogenesis and gravitropic sensitivity cannot. The root morphogenesis and gravitropism defects of adk1-1 are accompanied by altered expression of the PIN3 auxin efflux facilitator in the cap and decreased expression of the auxin-responsive DR5-GUS reporter. Furthermore, PIN3 fails to relocalize to the bottom membrane of statocytes upon gravistimulation. Consequently, adk1-1 roots cannot develop a lateral auxin gradient across the cap, necessary for the curvature response. Interestingly, adk1-1 does not affect gravity-induced cytoplasmic alkalinization of the root statocytes, suggesting either that ADK1 functions between cytoplasmic alkalinization and PIN3 relocalization in a linear pathway or that the pH and PIN3-relocalization responses to gravistimulation belong to distinct branches of the pathway. Our data are consistent with a role for ADK and the S-adenosyl-l-methionine pathway in the control of root gravitropism and cap morphogenesis. PMID:16891550

Expression Pattern of the Pro-apoptotic Gene PAR-4 During the Morphogenesis of MCF-10A Human Mammary Epithelial Cells.

PubMed

de Bessa Garcia, Simone A; Pereira, Michelly C; Nagai, Maria A

2010-12-21

The histological organization of the mammary gland involves a spatial interaction of epithelial and myoepithelial cells with the specialized basement membrane (BM), composed of extra-cellular matrix (ECM) proteins, which is disrupted during the tumorigenic process. The interactions between mammary epithelial cells and ECM components play a major role in mammary gland branching morphogenesis. Critical signals for mammary epithelial cell proliferation, differentiation, and survival are provided by the ECM proteins. Three-dimensional (3D) cell culture was developed to establish a system that simulates several features of the breast epithelium in vivo; 3D cell culture of the spontaneously immortalized cell line, MCF10A, is a well-established model system to study breast epithelial cell biology and morphogenesis. Mammary epithelial cells grown in 3D form spheroids, acquire apicobasal polarization, and form lumens that resemble acini structures, processes that involve cell death. Using this system, we evaluated the expression of the pro-apoptotic gene PAWR (PKC apoptosis WT1 regulator; also named PAR-4, prostate apoptosis response-4) by immunofluorescence and quantitative real time PCR (qPCR). A time-dependent increase in PAR-4 mRNA expression was found during the process of MCF10A acinar morphogenesis. Confocal microscopy analysis also showed that PAR-4 protein was highly expressed in the MCF10A cells inside the acini structure. During the morphogenesis of MCF10A cells in 3D cell culture, the cells within the lumen showed caspase-3 activation, indicating apoptotic activity. PAR-4 was only partially co-expressed with activated caspase-3 on these cells. Our results provide evidence, for the first time, that PAR-4 is differentially expressed during the process of MCF10A acinar morphogenesis.

Regulation of polarized morphogenesis by protein kinase C iota in oncogenic epithelial spheroids.

PubMed

Linch, Mark; Sanz-Garcia, Marta; Rosse, Carine; Riou, Philippe; Peel, Nick; Madsen, Chris D; Sahai, Erik; Downward, Julian; Khwaja, Asim; Dillon, Christian; Roffey, Jon; Cameron, Angus J M; Parker, Peter J

2014-02-01

Protein kinase C iota (PKCι), a serine/threonine kinase required for cell polarity, proliferation and migration, is commonly up- or downregulated in cancer. PKCι is a human oncogene but whether this is related to its role in cell polarity and what repertoire of oncogenes acts in concert with PKCι is not known. We developed a panel of candidate oncogene expressing Madin-Darby canine kidney (MDCK) cells and demonstrated that H-Ras, ErbB2 and phosphatidylinositol 3-kinase transformation led to non-polar spheroid morphogenesis (dysplasia), whereas MDCK spheroids expressing c-Raf or v-Src were largely polarized. We show that small interfering RNA (siRNA)-targeting PKCι decreased the size of all spheroids tested and partially reversed the aberrant polarity phenotype in H-Ras and ErbB2 spheroids only. This indicates distinct requirements for PKCι and moreover that different thresholds of PKCι activity are required for these phenotypes. By manipulating PKCι function using mutant constructs, siRNA depletion or chemical inhibition, we have demonstrated that PKCι is required for polarization of parental MDCK epithelial cysts in a 3D matrix and that there is a threshold of PKCι activity above and below which, disorganized epithelial morphogenesis results. Furthermore, treatment with a novel PKCι inhibitor, CRT0066854, was able to restore polarized morphogenesis in the dysplastic H-Ras spheroids. These results show that tightly regulated PKCι is required for normal-polarized morphogenesis in mammalian cells and that H-Ras and ErbB2 cooperate with PKCι for loss of polarization and dysplasia. The identification of a PKCι inhibitor that can restore polarized morphogenesis has implications for the treatment of Ras and ErbB2 driven malignancies.

Bmp signaling mediates endoderm pouch morphogenesis by regulating Fgf signaling in zebrafish.

PubMed

Lovely, C Ben; Swartz, Mary E; McCarthy, Neil; Norrie, Jacqueline L; Eberhart, Johann K

2016-06-01

The endodermal pouches are a series of reiterated structures that segment the pharyngeal arches and help pattern the vertebrate face. Multiple pathways regulate the complex process of endodermal development, including the Bone morphogenetic protein (Bmp) pathway. However, the role of Bmp signaling in pouch morphogenesis is poorly understood. Using genetic and chemical inhibitor approaches, we show that pouch morphogenesis requires Bmp signaling from 10-18 h post-fertilization, immediately following gastrulation. Blocking Bmp signaling during this window results in morphological defects to the pouches and craniofacial skeleton. Using genetic chimeras we show that Bmp signals directly to the endoderm for proper morphogenesis. Time-lapse imaging and analysis of reporter transgenics show that Bmp signaling is necessary for pouch outpocketing via the Fibroblast growth factor (Fgf) pathway. Double loss-of-function analyses demonstrate that Bmp and Fgf signaling interact synergistically in craniofacial development. Collectively, our analyses shed light on the tissue and signaling interactions that regulate development of the vertebrate face. © 2016. Published by The Company of Biologists Ltd.

klf2a couples mechanotransduction and zebrafish valve morphogenesis through fibronectin synthesis

PubMed Central

Steed, Emily; Faggianelli, Nathalie; Roth, Stéphane; Ramspacher, Caroline; Concordet, Jean-Paul; Vermot, Julien

2016-01-01

The heartbeat and blood flow signal to endocardial cell progenitors through mechanosensitive proteins that modulate the genetic program controlling heart valve morphogenesis. To date, the mechanism by which mechanical forces coordinate tissue morphogenesis is poorly understood. Here we use high-resolution imaging to uncover the coordinated cell behaviours leading to heart valve formation. We find that heart valves originate from progenitors located in the ventricle and atrium that generate the valve leaflets through a coordinated set of endocardial tissue movements. Gene profiling analyses and live imaging reveal that this reorganization is dependent on extracellular matrix proteins, in particular on the expression of fibronectin1b. We show that blood flow and klf2a, a major endocardial flow-responsive gene, control these cell behaviours and fibronectin1b synthesis. Our results uncover a unique multicellular layering process leading to leaflet formation and demonstrate that endocardial mechanotransduction and valve morphogenesis are coupled via cellular rearrangements mediated by fibronectin synthesis. PMID:27221222

Rap1, Canoe and Mbt cooperate with Bazooka to promote zonula adherens assembly in the fly photoreceptor

PubMed Central

Burki, Mubarik

2018-01-01

ABSTRACT In Drosophila epithelial cells, apical exclusion of Bazooka (the Drosophila Par3 protein) defines the position of the zonula adherens (ZA), which demarcates the apical and lateral membrane and allows cells to assemble into sheets. Here, we show that the small GTPase Rap1, its effector Canoe (Cno) and the Cdc42 effector kinase Mushroom bodies tiny (Mbt), converge in regulating epithelial morphogenesis by coupling stabilization of the adherens junction (AJ) protein E-Cadherin and Bazooka retention at the ZA. Furthermore, our results show that the localization of Rap1, Cno and Mbt at the ZA is interdependent, indicating that their functions during ZA morphogenesis are interlinked. In this context, we find the Rap1-GEF Dizzy is enriched at the ZA and our results suggest that it promotes Rap1 activity during ZA morphogenesis. Altogether, we propose the Dizzy, Rap1 and Cno pathway and Mbt converge in regulating the interface between Bazooka and AJ material to promote ZA morphogenesis. PMID:29507112

Ngn3+ endocrine progenitor cells control the fate and morphogenesis of pancreatic ductal epithelium

PubMed Central

Magenheim, Judith; Klein, Allon M.; Stanger, Ben Z.; Ashery-Padan, Ruth; Sosa-Pineda, Beatriz; Gu, Guoqiang; Dor, Yuval

2013-01-01

Summary During pancreas development, endocrine and exocrine cells arise from a common multipotent progenitor pool. How these cell fate decisions are coordinated with tissue morphogenesis is poorly understood. Here we have examined ductal morphology, endocrine progenitor cell fate and Notch signaling in Ngn3−/− mice, which do not produce islet cells. Ngn3 deficiency results in reduced branching and enlarged pancreatic duct-like structures, concomitant with Ngn3 promoter activation throughout the ductal epithelium and reduced Notch signaling. Conversely, forced generation of surplus endocrine progenitor cells causes reduced duct caliber and an excessive number of tip cells. Thus, endocrine progenitor cells normally provide a feedback signal to adjacent multipotent ductal progenitor cells that activates Notch signaling, inhibits further endocrine differentiation and promotes proper morphogenesis. These results uncover a novel layer of regulation coordinating pancreas morphogenesis and endocrine/exocrine differentiation, and suggest ways to enhance the yield of beta-cells from stem cells. PMID:21888903

Bmp signaling mediates endoderm pouch morphogenesis by regulating Fgf signaling in zebrafish

PubMed Central

Swartz, Mary E.; McCarthy, Neil; Norrie, Jacqueline L.; Eberhart, Johann K.

2016-01-01

The endodermal pouches are a series of reiterated structures that segment the pharyngeal arches and help pattern the vertebrate face. Multiple pathways regulate the complex process of endodermal development, including the Bone morphogenetic protein (Bmp) pathway. However, the role of Bmp signaling in pouch morphogenesis is poorly understood. Using genetic and chemical inhibitor approaches, we show that pouch morphogenesis requires Bmp signaling from 10-18 h post-fertilization, immediately following gastrulation. Blocking Bmp signaling during this window results in morphological defects to the pouches and craniofacial skeleton. Using genetic chimeras we show that Bmp signals directly to the endoderm for proper morphogenesis. Time-lapse imaging and analysis of reporter transgenics show that Bmp signaling is necessary for pouch outpocketing via the Fibroblast growth factor (Fgf) pathway. Double loss-of-function analyses demonstrate that Bmp and Fgf signaling interact synergistically in craniofacial development. Collectively, our analyses shed light on the tissue and signaling interactions that regulate development of the vertebrate face. PMID:27122171

Gonadal morphogenesis and gene expression in reptiles with temperature-dependent sex determination.

PubMed

Merchant-Larios, H; Díaz-Hernández, V; Marmolejo-Valencia, A

2010-01-01

In reptiles with temperature-dependent sexual determination, the thermosensitive period (TSP) is the interval in which the sex is defined during gonadal morphogenesis. One-shift experiments in a group of eggs define the onset and the end of the TSP as all and none responses, respectively. Timing for sex-undetermined (UG) and -determined gonads (DG) differs at male- (MPT) or female-producing temperatures (FPT). During the TSP a decreasing number of embryos respond to temperature shifts indicating that in this period embryos with both UG and DG exist. Although most UG correspond to undifferentiated gonads, some embryos extend UG after the onset of histological differentiation. Thus, temperature affects gonadal cells during the process of morphogenesis, but timing of commitment depends on individual embryos. A correlation between gonadal morphogenesis, TSP, and gene expression suggests that determination of the molecular pathways modulated by temperature in epithelial cells (surface epithelium and medullary cords) holds the key for a unifying hypothesis on temperature-dependent sex determination. (c) 2010 S. Karger AG, Basel.

An animal model of intrinsic dental erosion caused by gastro-oesophageal reflux disease.

PubMed

Higo, T; Mukaisho, K; Ling, Z-Q; Oue, K; Chen, K-H; Araki, Y; Sugihara, H; Yamamoto, G; Hattori, T

2009-07-01

To explore the association between dental erosion and gastro-oesophageal reflux disease (GORD), we used an animal model of GORD. We performed an operation to force gastro-duodenal contents reflux in male Wistar rats, and examined the teeth in the reflux rats at 15 or 30 weeks postoperatively. Dental erosion was evaluated based on a slightly modified index from a previous report. Estimation of pH was employed in the oesophageal and gastric contents. Macroscopically, dental erosion was only detected in the reflux rats. Histopathologically, dentin exposure was detected in three of the seven cases after 30 weeks. Alveolar bone destruction and osteomyelitis were also noted in severe cases. The pH of the oesophageal and stomach contents was 6.93 +/- 0.15 and 3.7 +/- 0.39, respectively. We confirmed the relationship between dental erosion and GORD. First step of dental erosion caused by GORD is the loss of surface enamel induced by regurgitation of an acidic liquid and acidic gas. Subsequently, further destruction of dental hard tissues and tooth supporting structure is accelerated by mixed juice with gastric and duodenal contents. The reflux animal model is a useful tool to examine the mechanism of dental erosion in GORD.

Endoscopic near-infrared dental imaging with indocyanine green: a pilot study.

PubMed

Li, Zhongqiang; Yao, Shaomian; Xu, Jian; Wu, Ye; Li, Chunhong; He, Ziying

2018-06-01

Current dental diagnosis, especially tooth abnormalities, relies largely on X-ray-based imaging, a technique that requires specialized skills and suffers from ionizing radiation. Here, we present a pilot study in rats of an efficient, ionizing-radiation-free and easy-to-use alternative for dental imaging. Postnatal rats at different ages were injected with indocyanine green and molars were imaged by a laboratory-designed endoscopic near-infrared (NIR) dental imaging system. The results indicate that the endoscopic NIR dental imaging can be used to observe the morphology of postnatal rat molars, especially at early postnatal stages when morphology of the molar is indistinguishable under visible conditions. A small abnormal cusp was observed and distinguished from the normal cusps by the NIR dental imaging system. Dental structures, such as unerupted molars, can be imaged as soon as 10 min after the injection of indocyanine green; imaging after 24 h shows improved imaging contrast. Overall, the endoscopic NIR fluorescence dental imaging system described here may be useful in dental research; this technique may serve as a safe, real-time imaging tool for dental diagnosis and treatment beyond experimental systems in the future. © 2018 New York Academy of Sciences.

Plant Growth and Morphogenesis under Different Gravity Conditions: Relevance to Plant Life in Space.

PubMed

Hoson, Takayuki

2014-05-16

The growth and morphogenesis of plants are entirely dependent on the gravitational acceleration of earth. Under microgravity conditions in space, these processes are greatly modified. Recent space experiments, in combination with ground-based studies, have shown that elongation growth is stimulated and lateral expansion suppressed in various shoot organs and roots under microgravity conditions. Plant organs also show automorphogenesis in space, which consists of altered growth direction and spontaneous curvature in the dorsiventral (back and front) directions. Changes in cell wall properties are responsible for these modifications of growth and morphogenesis under microgravity conditions. Plants live in space with interesting new sizes and forms.

Analysis of Transforming Growth Factor- β1 Expression in Resorptive Lacunae following Orthodontic Tooth Movement in An Animal Model.

PubMed

Seifi, Massoud; Kazemi, Bahram; Kabiri, Sattar; Badiee, Mohammadreza

2017-01-01

Root resorption is a complication of orthodontic treatment and till date, there is a dearth of information regarding this issue. The aim of this study was to determine whether the expression of transforming growth factor-β1 (TGF-β1, an inflammatory cytokine) is related to orthodontic force. Moreover, if associated, the expression level may be helpful in differential diagnosis, control and ultimate treatment of the disease. In this experimental study, a total of 24 eight-week-old male Wistar rats were selected randomly. On day 0, an orthodontic appliance, which consisted of a closed coil spring, was ligated to the upper right first molar and incisor. The upper left first molar in these animals was not placed under orthodontic force, thus serving as the control group. On day 21, after anesthesia, the animals were sacrificed. The rats were then divided into two equal groups where the first group was subjected to histological evaluation and the second group to reverse transcriptase-polymerase chain reaction (RT-PCR). Orthodontic tooth movement was measured in both groups to determine the influence of the applied force. Statistical analysis of data showed a significant root resorption between the experimental group and control group (P<0.05), however, there was no significant difference in the expression level of the inflammatory cytokine, TGF-β1 . Based on the findings of this study, we suggest that there is a direct relationship between orthodontic force and orthodontic induced inflammatory root resorption. In addition, no relationship is likely to exist between root resorption and TGF-β1 expression in the resorptive lacunae.

Analysis of Transforming Growth Factor- β1 Expression in Resorptive Lacunae following Orthodontic Tooth Movement in An Animal Model

PubMed Central

Seifi, Massoud; Kazemi, Bahram; Kabiri, Sattar; Badiee, Mohammadreza

2017-01-01

Objective Root resorption is a complication of orthodontic treatment and till date, there is a dearth of information regarding this issue. The aim of this study was to determine whether the expression of transforming growth factor-β1 (TGF-β1, an inflammatory cytokine) is related to orthodontic force. Moreover, if associated, the expression level may be helpful in differential diagnosis, control and ultimate treatment of the disease. Materials and Methods In this experimental study, a total of 24 eight-week-old male Wistar rats were selected randomly. On day 0, an orthodontic appliance, which consisted of a closed coil spring, was ligated to the upper right first molar and incisor. The upper left first molar in these animals was not placed under orthodontic force, thus serving as the control group. On day 21, after anesthesia, the animals were sacrificed. The rats were then divided into two equal groups where the first group was subjected to histological evaluation and the second group to reverse transcriptase-polymerase chain reaction (RT-PCR). Orthodontic tooth movement was measured in both groups to determine the influence of the applied force. Results Statistical analysis of data showed a significant root resorption between the experimental group and control group (P<0.05), however, there was no significant difference in the expression level of the inflammatory cytokine, TGF-β1. Conclusion Based on the findings of this study, we suggest that there is a direct relationship between orthodontic force and orthodontic induced inflammatory root resorption. In addition, no relationship is likely to exist between root resorption and TGF-β1 expression in the resorptive lacunae. PMID:28670520

Alendronate promotes bone formation by inhibiting protein prenylation in osteoblasts in rat tooth replantation model.

PubMed

Komatsu, Koichiro; Shimada, Akemi; Shibata, Tatsuya; Wada, Satoshi; Ideno, Hisashi; Nakashima, Kazuhisa; Amizuka, Norio; Noda, Masaki; Nifuji, Akira

2013-11-01

Bisphosphonates (BPs) are a major class of antiresorptive drug, and their molecular mechanisms of antiresorptive action have been extensively studied. Recent studies have suggested that BPs target bone-forming cells as well as bone-resorbing cells. We previously demonstrated that local application of a nitrogen-containing BP (N-BP), alendronate (ALN), for a short period of time increased bone tissue in a rat tooth replantation model. Here, we investigated cellular mechanisms of bone formation by ALN. Bone histomorphometry confirmed that bone formation was increased by local application of ALN. ALN increased proliferation of bone-forming cells residing on the bone surface, whereas it suppressed the number of tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts in vivo. Moreover, ALN treatment induced more alkaline phosphatase-positive and osteocalcin-positive cells on the bone surface than PBS treatment. In vitro studies revealed that pulse treatment with ALN promoted osteocalcin expression. To track the target cells of N-BPs, we applied fluorescence-labeled ALN (F-ALN) in vivo and in vitro. F-ALN was taken into bone-forming cells both in vivo and in vitro. This intracellular uptake was inhibited by endocytosis inhibitors. Furthermore, the endocytosis inhibitor dansylcadaverine (DC) suppressed ALN-stimulated osteoblastic differentiation in vitro and it suppressed the increase in alkaline phosphatase-positive bone-forming cells and subsequent bone formation in vivo. DC also blocked the inhibition of Rap1A prenylation by ALN in the osteoblastic cells. These data suggest that local application of ALN promotes bone formation by stimulating proliferation and differentiation of bone-forming cells as well as inhibiting osteoclast function. These effects may occur through endocytic incorporation of ALN and subsequent inhibition of protein prenylation.

Kidney and bladder calculi in spontaneously hypertensive rats.

PubMed Central

Wexler, B. C.; McMurtry, J. P.

1981-01-01

Naturally occurring kidney stones are rare in animals. The Japanese strains of spontaneously hypertensive rats (SHR) are normotensive at birth but develop high blood pressure, hyperglycaemia and hyperlipidaemia as they mature. The SHR strain is prone to develop kidney stones. A unique sub-strain of SHR has been developed in which some animals develop hypothalamic obesity concomitantly with their rising blood pressure, i.e. Obese/SHR. The Obese/SHR characteristically develop microscopic kidney stones which become detached at an early stage of formation, migrate to the bladder, and grow by concretion into huge, rounded calculi. The stone nidus starts as a subepithelial cyst-like focus containing oedema, colloidal acidic mucoprotein, and red and white blood cells suspended on a delicate network of fibrils. THe nidi grow by concretion of an admixture of calcium and acidic protein in a lamellar arrangement. The disparate morphogenesis and anatomic location of kidney stones in Obese is opposed to non-obese/SHR suggest that calculus formation may be governed by specific differences in genetic programming. The incidence of kidney stones parallels the severity and chronicity of the hypertension in SHR, non-obese and Obese/SHR, and the Cushingoid habitus in the Obese/SHR. Images Fig. 1 Fig. 3 Fig. 2 Fig. 4 Fig. 5 Fig. 6 PMID:7295530

Foregut separation and tracheo-oesophageal malformations: The role of tracheal outgrowth, dorso-ventral patterning and programmed cell death

PubMed Central

Ioannides, Adonis S.; Massa, Valentina; Ferraro, Elisabetta; Cecconi, Francesco; Spitz, Lewis; Henderson, Deborah J.; Copp, Andrew J.

2010-01-01

Foregut division—the separation of dorsal (oesophageal) from ventral (tracheal) foregut components—is a crucial event in gastro-respiratory development, and frequently disturbed in clinical birth defects. Here, we examined three outstanding questions of foregut morphogenesis. The origin of the trachea is suggested to result either from respiratory outgrowth or progressive septation of the foregut tube. We found normal foregut lengthening despite failure of tracheo-oesophageal separation in Adriamycin-treated embryos, whereas active septation was observed only in normal foregut morphogenesis, indicating a primary role for septation. Dorso-ventral patterning of Nkx2.1 (ventral) and Sox2 (dorsal) expression is proposed to be critical for tracheo-oesophageal separation. However, normal dorso-ventral patterning of Nkx2.1 and Sox2 expression occurred in Adriamycin-treated embryos with defective foregut separation. In contrast, Shh expression shifts dynamically, ventral-to-dorsal, solely during normal morphogenesis, particularly implicating Shh in foregut morphogenesis. Dying cells localise to the fusing foregut epithelial ridges, with disturbance of this apoptotic pattern in Adriamycin, Shh and Nkx2.1 models. Strikingly, however, genetic suppression of apoptosis in the Apaf1 mutant did not prevent foregut separation, indicating that apoptosis is not required for tracheo-oesophageal morphogenesis. Epithelial remodelling during septation may cause loss of cell-cell or cell-matrix interactions, resulting in apoptosis (anoikis) as a secondary consequence. PMID:19913007

WNTLESS IS REQUIRED FOR PERIPHERAL LUNG DIFFERENTIATION AND PULMONARY VASCULAR DEVELOPMENT

PubMed Central

Cornett, Bridget; Snowball, John; Varisco, Brian M.; Lang, Richard; Whitsett, Jeffrey; Sinner, Debora

2013-01-01

Wntless (Wls), a gene highly conserved across the animal kingdom, encodes for a transmembrane protein that mediates Wnt ligand secretion. Wls is expressed in developing lung, wherein Wnt signaling is necessary for pulmonary morphogenesis. We hypothesize that Wls plays a critical role in modulating Wnt signaling during lung development and therefore affects processes critical for pulmonary morphogenesis. We generated conditional Wls mutant mice utilizing Shh-Cre and Dermo1-Cre mice to delete Wls in the embryonic respiratory epithelium and mesenchyme, respectively. Epithelial deletion of Wls disrupted lung branching morphogenesis, peripheral lung development and pulmonary endothelial differentiation. Epithelial Wls mutant mice died at birth due to respiratory failure caused by lung hypoplasia and pulmonary hemorrhage. In the lungs of these mice, VEGF and Tie2-angiopoietin signaling pathways, which mediate vascular development, were downregulated from early stages of development. In contrast, deletion of Wls in mesenchymal cells of the developing lung did not alter branching morphogenesis or early mesenchymal differentiation. In vitro assays support the concept that Wls acts in part via Wnt5a to regulate pulmonary vascular development. We conclude that epithelial Wls modulates Wnt ligand activities critical for pulmonary vascular differentiation and peripheral lung morphogenesis. These studies provide a new framework for understanding the molecular mechanisms underlying normal pulmonary vasculature formation and the dysmorphic pulmonary vasculature development associated with congenital lung disease. PMID:23523683

Wntless is required for peripheral lung differentiation and pulmonary vascular development.

PubMed

Cornett, Bridget; Snowball, John; Varisco, Brian M; Lang, Richard; Whitsett, Jeffrey; Sinner, Debora

2013-07-01

Wntless (Wls), a gene highly conserved across the animal kingdom, encodes for a transmembrane protein that mediates Wnt ligand secretion. Wls is expressed in developing lung, wherein Wnt signaling is necessary for pulmonary morphogenesis. We hypothesize that Wls plays a critical role in modulating Wnt signaling during lung development and therefore affects processes critical for pulmonary morphogenesis. We generated conditional Wls mutant mice utilizing Shh-Cre and Dermo1-Cre mice to delete Wls in the embryonic respiratory epithelium and mesenchyme, respectively. Epithelial deletion of Wls disrupted lung branching morphogenesis, peripheral lung development and pulmonary endothelial differentiation. Epithelial Wls mutant mice died at birth due to respiratory failure caused by lung hypoplasia and pulmonary hemorrhage. In the lungs of these mice, VEGF and Tie2-angiopoietin signaling pathways, which mediate vascular development, were downregulated from early stages of development. In contrast, deletion of Wls in mesenchymal cells of the developing lung did not alter branching morphogenesis or early mesenchymal differentiation. In vitro assays support the concept that Wls acts in part via Wnt5a to regulate pulmonary vascular development. We conclude that epithelial Wls modulates Wnt ligand activities critical for pulmonary vascular differentiation and peripheral lung morphogenesis. These studies provide a new framework for understanding the molecular mechanisms underlying normal pulmonary vasculature formation and the dysmorphic pulmonary vasculature development associated with congenital lung disease. Copyright © 2013 Elsevier Inc. All rights reserved.

Geranylgeranyl Diphosphate Synthase Modulates Fetal Lung Branching Morphogenesis Possibly through Controlling K-Ras Prenylation.

PubMed

Jia, Wen-Jun; Jiang, Shan; Tang, Qiao-Li; Shen, Di; Xue, Bin; Ning, Wen; Li, Chao-Jun

2016-06-01

G proteins play essential roles in regulating fetal lung development, and any defects in their expression or function (eg, activation or posttranslational modification) can lead to lung developmental malformation. Geranylgeranyl diphosphate synthase (GGPPS) can modulate protein prenylation that is required for protein membrane-anchoring and activation. Here, we report that GGPPS regulates fetal lung branching morphogenesis possibly through controlling K-Ras prenylation during fetal lung development. GGPPS was continuously expressed in lung epithelium throughout whole fetal lung development. Specific deletion of geranylgeranyl diphosphate synthase 1 (Ggps1) in lung epithelium during fetal lung development resulted in neonatal respiratory distress syndrome-like disease. The knockout mice died at postnatal day 1 of respiratory failure, and the lungs showed compensatory pneumonectasis, pulmonary atelectasis, and hyaline membranes. Subsequently, we proved that lung malformations in Ggps1-deficient mice resulted from the failure of fetal lung branching morphogenesis. Further investigation revealed Ggps1 deletion blocked K-Ras geranylgeranylation and extracellular signal-related kinase 1 or 2/mitogen-activated protein kinase signaling, which in turn disturbed fibroblast growth factor 10 regulation on fetal lung branching morphogenesis. Collectively, our data suggest that GGPPS is essential for maintaining fetal lung branching morphogenesis, which is possibly through regulating K-Ras prenylation. Copyright © 2016 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Tissue architecture, cell traction, deformable scaffolds, and the forces that shape the embryo during morphogenesis.

NASA Astrophysics Data System (ADS)

Davidson, Lance

2005-03-01

Morphogenesis is the process of constucting form and shape. Morphogenesis during early development of the embryo involves orchestrated movements of cells and tissues. These morphogenetic movements establish the body plan and organs of the early embryo. The rates and trajectories of these movements depend on three physical features of the early embryo: 1) the forces generated by cells, 2) the mechanical properties of the tissues, and 3) the architecture of the tissues. These three mechanical features of the embryo are some of the earliest phenotypic features generated by the genome. We are taking an interdisciplinary approach combining biophysical, cell biological, and classical embryological techniques to understand the mechanics of morphogenesis. Using nanoNewton-sensitive force transducers we can apply forces and measure time dependent elastic modulii of tissue fragments 100 micrometers across. Using traction-force microscopy we can measure forces generated by cells on their environment. We use drugs and chimeric proteins to investigate the localization and function of molecular complexes responsible for force generation and the modulus. We use microsurgery to take-apart and construct novel tissues to investigate the role of geometry and architecture in the mechanics of morphogenesis. Together with simulation techniques these quantitative approaches will provide us with a practical nuts-and-bolts understanding of how the genome encodes the shapes and forms of life.

DRhoGEF2 and Diaphanous Regulate Contractile Force during Segmental Groove Morphogenesis in the Drosophila Embryo

PubMed Central

Mulinari, Shai; Barmchi, Mojgan Padash

2008-01-01

Morphogenesis of the Drosophila embryo is associated with dynamic rearrangement of the actin cytoskeleton mediated by small GTPases of the Rho family. These GTPases act as molecular switches that are activated by guanine nucleotide exchange factors. One of these factors, DRhoGEF2, plays an important role in the constriction of actin filaments during pole cell formation, blastoderm cellularization, and invagination of the germ layers. Here, we show that DRhoGEF2 is equally important during morphogenesis of segmental grooves, which become apparent as tissue infoldings during mid-embryogenesis. Examination of DRhoGEF2-mutant embryos indicates a role for DRhoGEF2 in the control of cell shape changes during segmental groove morphogenesis. Overexpression of DRhoGEF2 in the ectoderm recruits myosin II to the cell cortex and induces cell contraction. At groove regression, DRhoGEF2 is enriched in cells posterior to the groove that undergo apical constriction, indicating that groove regression is an active process. We further show that the Formin Diaphanous is required for groove formation and strengthens cell junctions in the epidermis. Morphological analysis suggests that Dia regulates cell shape in a way distinct from DRhoGEF2. We propose that DRhoGEF2 acts through Rho1 to regulate acto-myosin constriction but not Diaphanous-mediated F-actin nucleation during segmental groove morphogenesis. PMID:18287521

Structure and epitope distribution of heparan sulfate is disrupted in experimental lung hypoplasia: a glycobiological epigenetic cause for malformation?

PubMed

Thompson, Sophie M; Connell, Marilyn G; van Kuppevelt, Toin H; Xu, Ruoyan; Turnbull, Jeremy E; Losty, Paul D; Fernig, David G; Jesudason, Edwin C

2011-06-14

Heparan sulfate (HS) is present on the surface of virtually all mammalian cells and is a major component of the extracellular matrix (ECM), where it plays a pivotal role in cell-cell and cell-matrix cross-talk through its large interactome. Disruption of HS biosynthesis in mice results in neonatal death as a consequence of malformed lungs, indicating that HS is crucial for airway morphogenesis. Neonatal mortality (~50%) in newborns with congenital diaphragmatic hernia (CDH) is principally associated with lung hypoplasia and pulmonary hypertension. Given the importance of HS for lung morphogenesis, we investigated developmental changes in HS structure in normal and hypoplastic lungs using the nitrofen rat model of CDH and semi-synthetic bacteriophage ('phage) display antibodies, which identify distinct HS structures. The pulmonary pattern of elaborated HS structures is developmentally regulated. For example, the HS4E4V epitope is highly expressed in sub-epithelial mesenchyme of E15.5 - E17.5 lungs and at a lower level in more distal mesenchyme. However, by E19.5, this epitope is expressed similarly throughout the lung mesenchyme.We also reveal abnormalities in HS fine structure and spatiotemporal distribution of HS epitopes in hypoplastic CDH lungs. These changes involve structures recognised by key growth factors, FGF2 and FGF9. For example, the EV3C3V epitope, which was abnormally distributed in the mesenchyme of hypoplastic lungs, is recognised by FGF2. The observed spatiotemporal changes in HS structure during normal lung development will likely reflect altered activities of many HS-binding proteins regulating lung morphogenesis. Abnormalities in HS structure and distribution in hypoplastic lungs can be expected to perturb HS:protein interactions, ECM microenvironments and crucial epithelial-mesenchyme communication, which may contribute to lung dysmorphogenesis. Indeed, a number of epitopes correlate with structures recognised by FGFs, suggesting a functional consequence of the observed changes in HS in these lungs. These results identify a novel, significant molecular defect in hypoplastic lungs and reveals HS as a potential contributor to hypoplastic lung development in CDH. Finally, these results afford the prospect that HS-mimetic therapeutics could repair defective signalling in hypoplastic lungs, improve lung growth, and reduce CDH mortality.

Down-regulation of lung Kruppel-like factor in the nitrofen-induced hypoplastic lung.

PubMed

Lukošiūtė, A; Doi, T; Dingemann, J; Ruttenstock, E M; Puri, P

2011-01-01

Pulmonary hypoplasia is a primary cause of high morbidity and mortality in neonates with Congenital Diaphragmatic Hernia (CDH). However, the precise pathogenesis of PH associated with CDH is still not clearly understood. It has been recently reported that lung Kruppel-like factor (LKLF), a member of the Kruppel-like factor family of transcription factors, is predominantly expressed in lungs and plays an important role in lung morphogenesis and functional maturation. It has been reported that homozygous deletion of LKLF gene in mice results in reduced lung morphogenesis. It is further reported that chimeric mice derived from LKLF (-/-) embryonic stem cells exhibit delayed lung development especially in the later gestational stages. We therefore designed this study to test the hypothesis that the LKLF gene is down-regulated during later stages of lung development in nitrofen-induced hypoplastic lungs. Pregnant rats were exposed to either olive oil or nitrofen on day 9 of gestation (D9). Fetal lungs were harvested on D15, D18, and D21 and divided into 3 groups:control, nitrofen without CDH(CDH(-)) and nitrofen with CDH(CDH(+)) (n=24 for each group). Real-time RT-PCR analysis was performed to investigate pulmonary gene expression levels of LKLF. Differences between the 3 groups at each time point were tested statistically and significance was accepted at p<0.05. Immunohistochemistry was also performed to evaluate LKLF protein expression and distribution. The relative mRNA expression levels of LKLF on D18 and D21 were significantly decreased (p<0.01) in CDH(-) and CDH(+) groups compared to controls. The gene expression levels of LKLF on D15 did not differ significantly between the nitrofen group and controls. Immunohistochemical study showed strong LKLF immunoreactivity on D18 and D21 in nitrofen-induced hypoplastic lung compared to controls, whereas no difference was seen on D15. Our results provide evidence for the first time that LKLF is down-regulated in the later stages of lung development in nitrofen-induced hypoplastic lungs. These data suggest that the down-regulation of LKLF during this critical period of lung morphogenesis may impair lung development and maturation, resulting in pulmonary hypoplasia in the nitrofen CDH model. © Georg Thieme Verlag KG Stuttgart · New York.

Structure and epitope distribution of heparan sulfate is disrupted in experimental lung hypoplasia: a glycobiological epigenetic cause for malformation?

PubMed Central

2011-01-01

Background Heparan sulfate (HS) is present on the surface of virtually all mammalian cells and is a major component of the extracellular matrix (ECM), where it plays a pivotal role in cell-cell and cell-matrix cross-talk through its large interactome. Disruption of HS biosynthesis in mice results in neonatal death as a consequence of malformed lungs, indicating that HS is crucial for airway morphogenesis. Neonatal mortality (~50%) in newborns with congenital diaphragmatic hernia (CDH) is principally associated with lung hypoplasia and pulmonary hypertension. Given the importance of HS for lung morphogenesis, we investigated developmental changes in HS structure in normal and hypoplastic lungs using the nitrofen rat model of CDH and semi-synthetic bacteriophage ('phage) display antibodies, which identify distinct HS structures. Results The pulmonary pattern of elaborated HS structures is developmentally regulated. For example, the HS4E4V epitope is highly expressed in sub-epithelial mesenchyme of E15.5 - E17.5 lungs and at a lower level in more distal mesenchyme. However, by E19.5, this epitope is expressed similarly throughout the lung mesenchyme. We also reveal abnormalities in HS fine structure and spatiotemporal distribution of HS epitopes in hypoplastic CDH lungs. These changes involve structures recognised by key growth factors, FGF2 and FGF9. For example, the EV3C3V epitope, which was abnormally distributed in the mesenchyme of hypoplastic lungs, is recognised by FGF2. Conclusions The observed spatiotemporal changes in HS structure during normal lung development will likely reflect altered activities of many HS-binding proteins regulating lung morphogenesis. Abnormalities in HS structure and distribution in hypoplastic lungs can be expected to perturb HS:protein interactions, ECM microenvironments and crucial epithelial-mesenchyme communication, which may contribute to lung dysmorphogenesis. Indeed, a number of epitopes correlate with structures recognised by FGFs, suggesting a functional consequence of the observed changes in HS in these lungs. These results identify a novel, significant molecular defect in hypoplastic lungs and reveals HS as a potential contributor to hypoplastic lung development in CDH. Finally, these results afford the prospect that HS-mimetic therapeutics could repair defective signalling in hypoplastic lungs, improve lung growth, and reduce CDH mortality. PMID:21672206

Pulp Cell Tracking by Radionuclide Imaging for Dental Tissue Engineering

PubMed Central

Souron, Jean-Baptiste; Petiet, Anne; Decup, Franck; Tran, Xuan Vinh; Lesieur, Julie; Poliard, Anne; Le Guludec, Dominique; Letourneur, Didier; Chaussain, Catherine; Rouzet, Francois

2014-01-01

Pulp engineering with dental mesenchymal stem cells is a promising therapy for injured teeth. An important point is to determine the fate of implanted cells in the pulp over time and particularly during the early phase following implantation. Indeed, the potential engraftment of the implanted cells in other organs has to be assessed, in particular, to evaluate the risk of inducing ectopic mineralization. In this study, our aim was to follow by nuclear imaging the radiolabeled pulp cells after implantation in the rat emptied pulp chamber. For that purpose, indium-111-oxine (111In-oxine)-labeled rat pulp cells were added to polymerizing type I collagen hydrogel to obtain a pulp equivalent. This scaffold was implanted in the emptied pulp chamber space in the upper first rat molar. Labeled cells were then tracked during 3 weeks by helical single-photon emission computed tomography (SPECT)/computed tomography performed on a dual modality dedicated small animal camera. Negative controls were performed using lysed radiolabeled cells obtained in a hypotonic solution. In vitro data indicated that 111In-oxine labeling did not affect cell viability and proliferation. In vivo experiments allowed a noninvasive longitudinal follow-up of implanted living cells for at least 3 weeks and indicated that SPECT signal intensity was related to implanted cell integrity. Notably, there was no detectable systemic release of implanted cells from the tooth. In addition, histological analysis of the samples showed mitotically active fibroblastic cells as well as neoangiogenesis and nervous fibers in pulp equivalents seeded with entire cells, whereas pulp equivalents prepared from lysed cells were devoid of cell colonization. In conclusion, our study demonstrates that efficient labeling of pulp cells can be achieved and, for the first time, that these cells can be followed up after implantation in the tooth by nuclear imaging. Furthermore, it appears that grafted cells retained the label and are viable to follow the repair process. This technique is expected to be of major interest for monitoring implanted cells in innovative therapies for injured teeth. PMID:23789732

Newt tail regeneration: a model for gravity-dependent morphogenesis and clues to the molecular mechanisms involved.

NASA Astrophysics Data System (ADS)

Radugina, Elena A.; Almeida, Eduardo; Grigoryan, Eleonora

Gravity alterations are widely recognized to influence living systems. They may cause temporary or permanent effects on physiology and development at different levels, from gene expression to morphogenesis. However, the molecular mechanisms underlying these effects are often unclear, and adequate model systems to study them are required. To address this problem we developed a new experimental model of how gravity affects morphogenesis during tail regeneration in the newt Pleurodeles waltl. The effects of increased gravity on newt tail morphogenesis were first documented in two joint Russian-US NASA spaceflight experiments in the Russian Foton-M2 (2005) and Foton-M3 (2007) missions. In these experiments the shape of newt tail regenerate was found to depend on the gravity level, being dorso-ventrally symmetrical in microgravity and in neutrally-buoyant aquarium controls, versus hook-like and bent downward in 1g controls. These 1g controls were conducted in spaceflight habitats using a water-saturated PVA sponge mat. These results were reproducible in multiple spaceflight, and ground laboratory studies, both in the US at NASA ARC and in Russia at IDB RAS, and were characterized in detail using morphometry and histology approaches. The role of hypergravity in shaping morphogenesis was confirmed at NASA ARC with an experiment in the ISS Testbed 8-foot diameter centrifuge operating at 2g. Animals that experienced two-week centrifugation (the period of time used in the Foton flights) developed the same hook-like regenerates as 1g controls, and morphometric analysis revealed no significant difference between 1g and 2g groups, however both were significantly different from aquarium controls. We hypothesize that exposure to 1g or 2g during tail morphogenesis constitutes excessive loading for newts that are adapted to microgravity-like conditions in their aquatic habitat. Because Heat Shock Proteins (HSPs) are stress-induced molecules that respond to a broad variety of factors and are expressed during development, we hypothesized they may play a role newt tail regenerative morphogenesis under altered g-levels. Specifically there is increasing evidence for HSPs expression changes as a result of hyper-and microgravity. HSPs are also expressed throughout regeneration, rather than just after surgery. To test this hypothesis we performed heat shock on intact and regenerating newts and collected tail tissues. In these experiments we observed that some tails had uplifted tips while others mimicked hook-like regenerates at 1g or 2g. These findings suggest that heat shock, and HSPs induction, may be involved in the mechanism responsible for gravity effects on morphogenesis, or at least interact with them. Current work underway is focused on analyzing the expression of mRNA and localization of proteins for two members of the group, Hsp70 and Hsp90. In summary, we developed and characterized a new practical animal model in which gravity mechanostimulation at 1g, versus unloading in aquaria, causes prominent effects on newt tail regenerative morphogenesis. This model can be achieved without the use of a centrifuge, significantly simplifying its research applications. Initial results using this model suggest that induction of HSPs may be involved in gravity regulation of newt tail regenerative morphogenesis. Further research based on this simple model may help to unravel mechanisms of gravity influence relevant not only to newt tail regeneration, but also to a broad range of other biological processes in amphibian models.

Evolution of high tooth replacement rates in sauropod dinosaurs.

PubMed

D'Emic, Michael D; Whitlock, John A; Smith, Kathlyn M; Fisher, Daniel C; Wilson, Jeffrey A

2013-01-01

Tooth replacement rate can be calculated in extinct animals by counting incremental lines of deposition in tooth dentin. Calculating this rate in several taxa allows for the study of the evolution of tooth replacement rate. Sauropod dinosaurs, the largest terrestrial animals that ever evolved, exhibited a diversity of tooth sizes and shapes, but little is known about their tooth replacement rates. We present tooth replacement rate, formation time, crown volume, total dentition volume, and enamel thickness for two coexisting but distantly related and morphologically disparate sauropod dinosaurs Camarasaurus and Diplodocus. Individual tooth formation time was determined by counting daily incremental lines in dentin. Tooth replacement rate is calculated as the difference between the number of days recorded in successive replacement teeth. Each tooth family in Camarasaurus has a maximum of three replacement teeth, whereas each Diplodocus tooth family has up to five. Tooth formation times are about 1.7 times longer in Camarasaurus than in Diplodocus (315 vs. 185 days). Average tooth replacement rate in Camarasaurus is about one tooth every 62 days versus about one tooth every 35 days in Diplodocus. Despite slower tooth replacement rates in Camarasaurus, the volumetric rate of Camarasaurus tooth replacement is 10 times faster than in Diplodocus because of its substantially greater tooth volumes. A novel method to estimate replacement rate was developed and applied to several other sauropodomorphs that we were not able to thin section. Differences in tooth replacement rate among sauropodomorphs likely reflect disparate feeding strategies and/or food choices, which would have facilitated the coexistence of these gigantic herbivores in one ecosystem. Early neosauropods are characterized by high tooth replacement rates (despite their large tooth size), and derived titanosaurs and diplodocoids independently evolved the highest known tooth replacement rates among archosaurs.

Evolution of High Tooth Replacement Rates in Sauropod Dinosaurs

PubMed Central

Smith, Kathlyn M.; Fisher, Daniel C.; Wilson, Jeffrey A.

2013-01-01

Background Tooth replacement rate can be calculated in extinct animals by counting incremental lines of deposition in tooth dentin. Calculating this rate in several taxa allows for the study of the evolution of tooth replacement rate. Sauropod dinosaurs, the largest terrestrial animals that ever evolved, exhibited a diversity of tooth sizes and shapes, but little is known about their tooth replacement rates. Methodology/Principal Findings We present tooth replacement rate, formation time, crown volume, total dentition volume, and enamel thickness for two coexisting but distantly related and morphologically disparate sauropod dinosaurs Camarasaurus and Diplodocus. Individual tooth formation time was determined by counting daily incremental lines in dentin. Tooth replacement rate is calculated as the difference between the number of days recorded in successive replacement teeth. Each tooth family in Camarasaurus has a maximum of three replacement teeth, whereas each Diplodocus tooth family has up to five. Tooth formation times are about 1.7 times longer in Camarasaurus than in Diplodocus (315 vs. 185 days). Average tooth replacement rate in Camarasaurus is about one tooth every 62 days versus about one tooth every 35 days in Diplodocus. Despite slower tooth replacement rates in Camarasaurus, the volumetric rate of Camarasaurus tooth replacement is 10 times faster than in Diplodocus because of its substantially greater tooth volumes. A novel method to estimate replacement rate was developed and applied to several other sauropodomorphs that we were not able to thin section. Conclusions/Significance Differences in tooth replacement rate among sauropodomorphs likely reflect disparate feeding strategies and/or food choices, which would have facilitated the coexistence of these gigantic herbivores in one ecosystem. Early neosauropods are characterized by high tooth replacement rates (despite their large tooth size), and derived titanosaurs and diplodocoids independently evolved the highest known tooth replacement rates among archosaurs. PMID:23874921

The effect of in vitro tracheal occlusion on branching morphogenesis in fetal lung explants from the rat nitrofen model of congenital diaphragmatic hernia.

PubMed

Grushka, Jeremy R; Al-Abbad, Saleh; Baird, Robert; Puligandla, Pramod; Kaplan, Feige; Laberge, Jean-Martin

2010-05-01

Fetal tracheal occlusion (TO) has been investigated as a treatment option for lung hypoplasia secondary to congenital diaphragmatic hernia. Tracheal occlusion has been shown to accelerate lung growth, but its effect on bronchial branching is unknown. In this study, we characterize the effects of in vitro TO on bronchial branch development in fetal lung explants derived from the nitrofen rat model of congenital diaphragmatic hernia. Rat dams were gavaged nitrofen on gestational day 9.5, and fetal lungs were harvested for explant culture on gestational day 14 (term, 22 days). Four experimental groups were investigated, with TO performed ex vivo using cautery: control, control + TO, nitrofen, and nitrofen + TO. Explants were incubated for 72 hours. Representative photographs were taken at 0, 24, 48, and 72 hours from the time of culture, and the number of distal branches was counted for each explant. The Student t test was used to compare distal branch measurements. A minimum of 12 fetal lung explants were cultured for each group. By 24 hours, all explants undergoing TO had more branch iterations than explants that did not. Moreover, TO in nitrofen-exposed explants increased bronchial branching to control levels by 24 hours in culture. Our results suggest that TO at day 14 increases branching in normal and nitrofen-exposed lung explants. In addition, TO increases airway branching in nitrofen-exposed explants to control levels suggesting that early TO reverses the lung hypoplasia seen in this model. Copyright (c) 2010 Elsevier Inc. All rights reserved.

Transduction of Wnt11 promotes mesenchymal stem cell transdifferentiation into cardiac phenotypes.

PubMed

He, Zhisong; Li, Hongxia; Zuo, Shi; Pasha, Zeeshan; Wang, Yigang; Yang, Yueting; Jiang, Wenping; Ashraf, Muhammad; Xu, Meifeng

2011-10-01

Transplantation of mesenchymal stem cells (MSCs) has emerged as a potential treatment for ischemic heart repair. Previous studies have suggested that Wnt11 plays a critical role in cardiac specification and morphogenesis. In this study, we examined whether transduction of Wnt11 directly increases MSC differentiation into cardiac phenotypes. MSCs harvested from rat bone marrow were transduced with both Wnt11 and green fluorescent protein (GFP) (MSC(Wnt11)) using the murine stem cell virus (pMSCV) retroviral expression system; control cells were only GFP-transfected (MSC(Null)). Compared with control cells, MSC(Wnt11) was shown to have higher expression of Wnt11 by immunofluorescence, real-time polymerase chain reaction, and western blotting. MSC(Wnt11) shows a higher expression of cardiac-specific genes, including GATA-4, brain natriuretic peptide (BNP), islet-1, and α-actinin, after being cultured with cardiomyocytes (CMs) isolated from ventricles of neonatal (1-3 day) SD rats. Some MSC(Wnt11) were positive for α-actinin when MSCs were cocultured with native CMs for 7 days. Electron microscopy further confirmed the appearance of sarcomeres in MSC(Wnt11). Connexin 43 was found between GFP-positive MSCs and neonatal rat CMs labeled with red fluorescent probe PKH26. The transdifferentiation rate was significantly higher in MSC(Wnt11) than in MSC(Null), as assessed by flow cytometry. Functional studies indicated that the differentiation of MSC(Wnt11) was diminished by knockdown of GATA-4 with GATA-4-siRNA. Transduction of Wnt11 into MSCs increases their differentiation into CMs by upregulating GATA-4.

Gravity and animal embryos

NASA Technical Reports Server (NTRS)

Wiley, Lynn M.

1989-01-01

Out of more than 4,500 rat hours in space there was only one experimental attempt (Cosmos 1129) at mating with an apparent absence of fertilization, implantation and subsequent development to term and partuition. Portions of this process were successfully flown, however, including the major portion of organogenesis in the rat (Cosmos 1524). These observations show that the cellular and molecular events underlying morphogenesis and differentiation in a small mammal can proceed normally in-utero under microgravity and other conditions encountered during short-duration flight. However, it is not known whether this situation will hold for larger mammals over several generations during extended missions that venture outside of near Earth. Furthermore, it is not understood why the previous attempt at obtaining copulation, fertilization and implantation in orbit failed but may be related to limitations of the rat habitat for meeting the preconditions for reproductive behavior. With respect to mammalian development it is important to appreciate that fertilization and development occur internally within the female and take a long time to complete and their success will, therefore, be contingent upon the maternal response to the space environment. One process central to development (the establishment of cell lines) is initiated prior to implantation by environmental asymmetries preceived by progenitor cells. These asymmetries appear to result from the formation of asymmetric cell-cell contacts and the concommitant development of an electrical axis across the progenitor cells. Other asymmetries were also documented. It is not known whether any of the known asymmetries perceived by progenitor cells are influenced by gravity vectors and/or by the maternal response to microgravity and other conditions encountered in space.

Evaluation of an experimental rat model for comparative studies of bleaching agents

PubMed Central

CINTRA, Luciano Tavares Angelo; BENETTI, Francine; FERREIRA, Luciana Louzada; RAHAL, Vanessa; ERVOLINO, Edilson; JACINTO, Rogério de Castilho; GOMES, João Eduardo; BRISO, André Luiz Fraga

2016-01-01

ABSTRACT Dental materials in general are tested in different animal models prior to the clinical use in humans, except for bleaching agents. Objectives To evaluate an experimental rat model for comparative studies of bleaching agents, by investigating the influence of different concentrations and application times of H2O2 gel in the pulp tissue during in-office bleaching of rats’ vital teeth. Material and Methods The right and left maxillary molars of 50 Wistar rats were bleached with 20% and 35% H2O2 gels, respectively, for 5, 10, 15, 30, or 45 min (n=10 rats/group). Ten animals were untreated (control). The rats were killed after 2 or 30 days, and the maxillae were examined by light microscopy. Inflammation was evaluated through histomorphometric analysis with inflammatory cell count in the coronal and radicular thirds of the pulp. Fibroblasts were also counted. Scores were attributed to odontoblastic layer and vascular changes. Tertiary dentin area and pulp chamber central area were measured histomorphometrically. Data were compared by analysis of variance and Kruskal-Wallis test (p<0.05). Results After 2 days, the amount of inflammatory cells increased in the coronal pulp occlusal third up to the 15-min application groups of each bleaching gel. In the groups exposed to each concentration for 30 and 45 min, the number of inflammatory cells decreased along with the appearance of necrotic areas. After 30 days, reduction on the pulp chamber central area and enlargement of the tertiary dentin area were observed, without the detection of inflammation areas. Conclusion The rat model of extracoronal bleaching showed to be adequate for studies of bleaching protocols, as it was possible to observe alterations in the pulp tissues and tooth structure caused by different concentrations and application periods of bleaching agents. PMID:27119766

[Expression and significance of wingless-type MMTV integration site family, member 5A/receptor tyrosine kinase-like orphan receptor 2 in the rat dental follicle].

PubMed

Liping, Wang; Boqi, Li; Qi, Wang; Xiaomin, Tie; Yishan, Liu

2016-08-01

To observe the expression of wingless-type MMTV integration site family, member 5A (Wnt5A)/receptor tyrosine kinase-like orphan receptor 2 (Ror2) signal in the dental follicle cells during the normal eruption of the teeth as well as to explore the relationship between the expression of dental follicle cells and the formation of mature osteoclasts and eruption of the teeth. The mandibulars of 1-13 d old SD rats were separated to observe the growth and develop-ment of the teeth and alveolar bone through hematoxylin-eosin(HE) staining. Ror2 and Wnt5A expressions in rat dental follicle were also observed through immunohistochemistry. Dental follicle cells from the lower first intact molar germs of 5-6-day old SD rats were separated and cultured. On the second day after birth, the dental follicle began to differentiate into periodontal tissues, but no obvious changes were observed in the alveolar bone one to three days after birth. On the fourth day, the number of osteoclasts increased significantly. The results of immunohistochemistry showed that Wnt5A was not significantly expressed in rat dental follicle tissues before the fourth day, but positive expression was expressed in the next day and continued to express to thirteenth days. Ror2 was expressed in the rat dental follicle at postnatal days 1-3, but weak expression was found in days 4-13. Wnt5A and Ror2 expressions in the process of tooth eruption have specific time distributions, suggesting that these expressions may participate in the regulation of the eruption of the teeth.

Mechanics and morphogenesis of fission yeast cells.

PubMed

Davì, Valeria; Minc, Nicolas

2015-12-01

The integration of biochemical and biomechanical elements is at the heart of morphogenesis. While animal cells are relatively soft objects which shape and mechanics is mostly regulated by cytoskeletal networks, walled cells including those of plants, fungi and bacteria are encased in a rigid cell wall which resist high internal turgor pressure. How these particular mechanical properties may influence basic cellular processes, such as growth, shape and division remains poorly understood. Recent work using the model fungal cell fission yeast, Schizosaccharomyces pombe, highlights important contribution of cell mechanics to various morphogenesis processes. We envision this genetically tractable system to serve as a novel standard for the mechanobiology of walled cell. Copyright © 2015 Elsevier Ltd. All rights reserved.

To grow or not to grow: Hair morphogenesis and human genetic hair disorders

PubMed Central

Duverger, Olivier; Morasso, Maria I.

2014-01-01

Mouse models have greatly helped in elucidating the molecular mechanisms involved in hair formation and regeneration. Recent publications have reviewed the genes involved in mouse hair development based on the phenotype of transgenic, knockout and mutant animal models. While much of this information has been instrumental in determining molecular aspects of human hair development and cycling, mice exhibit a specific pattern of hair morphogenesis and hair distribution throughout the body that cannot be directly correlated to human hair. In this mini-review, we discuss specific aspects of human hair follicle development and present an up-to-date summary of human genetic disorders associated with abnormalities in hair follicle morphogenesis, structure or regeneration. PMID:24361867

Dentin and pulp sense cold stimulus.

PubMed

Tokuda, Masayuki; Tatsuyama, Shoko; Fujisawa, Mari; Morimoto-Yamashita, Yoko; Kawakami, Yoshiko; Shibukawa, Yoshiyuki; Torii, Mistuso

2015-05-01

Dentin hypersensitivity is a common symptom, and recent convergent evidences have reported transient receptor potential (TRP) channels in odontoblasts act as mechanical and thermal molecular sensor, which detect stimulation applied on the exposed dentin surface, to drive multiple odontoblastic cellular functions, such as sensory transduction and/or dentin formation. In the present study, we confirmed expression of TRP melastatin subfamily member-8 (TRPM8) channels in primary cultured cells derived from human dental pulp cells (HPCs) and mouse odontoblast-lineage cells (OLCs) as well as in dentin matrix protein-1 (DMP-1) and dentin sialoprotein (DSP) positive acutely isolated rat odontoblasts from dental pulp tissue slice culture by immunohistochemical analyses. In addition, we detected TRPM8 channel expression on HPCs and OLCs by RT-PCR and Western blotting analyses. These results indicated that both odontoblasts and dental pulp cells express TRPM8 channels in rat, mouse and human, and therefore we hypothesize they may contribute as cold sensor in tooth. Copyright © 2015 Elsevier Ltd. All rights reserved.

A Case of endoscopic retrieval of a long bamboo stick from a Humboldt penguin (Spheniscus humboldti).

PubMed

Jung, Woo-Sung; Ko, Minho; Cho, Hyun Kee; Kang, Byung-Jae; Choi, Jung Hoon; Chung, Jin-Young

2017-02-28

An eighteen-month-old female Humboldt penguin (Spheniscus humboldti) that was 50 cm in length and 4.5 kg in weight was presented with anorexia and vomiting. The hematological and blood biochemical profiles revealed no remarkable findings, and no Salmonella, Shigella or Vibrio spp. were isolated from the fecal culture. However, radiographic imaging revealed a long linear foreign body presenting from the lower esophagus to the stomach. To retrieve this foreign body, flexible endoscopic extraction was performed using flexible rat tooth grasping forceps. A long bamboo stick (29 × 1 cm) was removed from the stomach, and the penguin fully recovered.

A Case of endoscopic retrieval of a long bamboo stick from a Humboldt penguin (Spheniscus humboldti)

PubMed Central

JUNG, Woo-Sung; KO, Minho; CHO, Hyun Kee; KANG, Byung-Jae; CHOI, Jung Hoon; CHUNG, Jin-Young

2016-01-01

An eighteen-month-old female Humboldt penguin (Spheniscus humboldti) that was 50 cm in length and 4.5 kg in weight was presented with anorexia and vomiting. The hematological and blood biochemical profiles revealed no remarkable findings, and no Salmonella, Shigella or Vibrio spp. were isolated from the fecal culture. However, radiographic imaging revealed a long linear foreign body presenting from the lower esophagus to the stomach. To retrieve this foreign body, flexible endoscopic extraction was performed using flexible rat tooth grasping forceps. A long bamboo stick (29 × 1 cm) was removed from the stomach, and the penguin fully recovered. PMID:27990010

Adhesion mechanisms in embryogenesis and in cancer invasion and metastasis.

PubMed

Thiery, J P; Boyer, B; Tucker, G; Gavrilovic, J; Valles, A M

1988-01-01

Cell-substratum and cell-cell adhesion mechanisms contribute to the development of animal form. The adhesive status of embryonic cells has been analysed during epithelial-mesenchymal cell interconversion and in cell migrations. Clear-cut examples of the modulation of cell adhesion molecules (CAMs) have been described at critical periods of morphogenesis. In chick embryos the three primary CAMs (N-CAM. L-CAM and N-cadherin) present early in embryogenesis are expressed later in a defined pattern during morphogenesis and histogenesis. The axial mesoderm derived from gastrulating cells expresses increasing amounts of N-cadherin and N-CAM. During metamerization these two adhesion molecules become abundant at somitic cell surfaces. Both CAMs are functional in an in vitro aggregation assay; however, the calcium-dependent adhesion molecule N-cadherin is more sensitive to perturbation by specific antibodies. Neural crest cells which separate from the neural epithelium lose their primary CAMs in a defined time-sequence. Adhesion to fibronectins via specific surface receptors becomes a predominant interaction during the migratory process, while some primary and secondary CAMs are expressed de novo during the ontogeny of the peripheral nervous system. In vitro, different fibronectin functional domains have been identified in the attachment, spreading and migration of neural crest cells. The fibronectin receptors which transduce the adhesive signals play a key role in the control of cell movement. All these results have prompted us to examine whether similar mechanisms operate in carcinoma cell invasion and metastasis. In vitro, rat bladder transitional carcinoma cells convert reversibly into invasive mesenchymal cells. A rapid modulation of adhesive properties is found during the epithelial-mesenchymal carcinoma cell interconversion. The different model systems analysed demonstrate that a limited repertoire of adhesion molecules, expressed in a well-defined spatiotemporal pattern, is involved in tissue formation and in key processes of tumour spread.

Profilin is required for viral morphogenesis, syncytium formation, and cell-specific stress fiber induction by respiratory syncytial virus

PubMed Central

Bitko, Vira; Oldenburg, Anja; Garmon, Nicolle E; Barik, Sailen

2003-01-01

Background Actin is required for the gene expression and morphogenesis of respiratory syncytial virus (RSV), a clinically important Pneumovirus of the Paramyxoviridae family. In HEp-2 cells, RSV infection also induces actin stress fibers, which may be important in the immunopathology of the RSV disease. Profilin, a major regulator of actin polymerization, stimulates viral transcription in vitro. Thus, we tested the role of profilin in RSV growth and RSV-actin interactions in cultured cells (ex vivo). Results We tested three cell lines: HEp-2 (human), A549 (human), and L2 (rat). In all three, RSV grew well and produced fused cells (syncytium), and two RSV proteins, namely, the phosphoprotein P and the nucleocapsid protein N, associated with profilin. In contrast, induction of actin stress fibers by RSV occurred in HEp-2 and L2 cells, but not in A549. Knockdown of profilin by RNA interference had a small effect on viral macromolecule synthesis but strongly inhibited maturation of progeny virions, cell fusion, and induction of stress fibers. Conclusions Profilin plays a cardinal role in RSV-mediated cell fusion and viral maturation. In contrast, interaction of profilin with the viral transcriptional proteins P and N may only nominally activate viral RNA-dependent RNA polymerase. Stress fiber formation is a cell-specific response to infection, requiring profilin and perhaps other signaling molecules that are absent in certain cell lines. Stress fibers per se play no role in RSV replication in cell culture. Clearly, the cellular architecture controls multiple steps of host-RSV interaction, some of which are regulated by profilin. PMID:12740026

Myelin protein zero gene mutated in Charcot-Marie-Tooth type 1B patients

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

Su, Ying; Li, Lanying; Lepercq, J.

1993-11-15

The autosomal dominant of Charcot-Marie-Tooth disease (CMT), whose gene is type 1B (CMT1B), has slow nerve conduction with demyelinated Schwann cells. In this study the abundant peripheral myelin protein zero (MPZ) gene, MPZ, was mapped 130 kb centromeric to the Fc receptor immunoglobulin gene cluster in band 1q22, and a major MPZ point mutation was found to cosegregate with CMT1B in one large CMT1B family. The MPZ point mutation in 18 of 18 related CMT1B pedigree 1 patients converts a positively charged lysine in codon 96 to a negatively charged glutamate. The same MPZ locus cosegregates with the CMT1B diseasemore » gene in a second CMT1B family [total multipoint logarithm of odds (lod) = 11.4 at [theta] = 0.00] with a splice junction mutation. Both mutations occur in MPZ protein regions otherwise conserved identically in human, rat, and cow since these species diverged 100 million years ago. MPZ protein, expressed exclusively in myelinated peripheral nerve Schwann cells, constitutes >50% of myelin protein. These mutations are anticipated to disrupt homophilic MPZ binding and result in CMT1B peripheral nerve demyelination.« less

Modulation of Morphogenesis in Candida albicans by Various Small Molecules ▿

PubMed Central

Shareck, Julie; Belhumeur, Pierre

2011-01-01

The pathogenic yeast Candida albicans, a member of the mucosal microbiota, is responsible for a large spectrum of infections, ranging from benign thrush and vulvovaginitis in both healthy and immunocompromised individuals to severe, life-threatening infections in immunocompromised patients. A striking feature of C. albicans is its ability to grow as budding yeast and as filamentous forms, including hyphae and pseudohyphae. The yeast-to-hypha transition contributes to the overall virulence of C. albicans and may even constitute a target for the development of antifungal drugs. Indeed, impairing morphogenesis in C. albicans has been shown to be a means to treat candidiasis. Additionally, a large number of small molecules such as farnesol, fatty acids, rapamycin, geldanamycin, histone deacetylase inhibitors, and cell cycle inhibitors have been reported to modulate the yeast-to-hypha transition in C. albicans. In this minireview, we take a look at molecules that modulate morphogenesis in this pathogenic yeast. When possible, we address experimental findings regarding their mechanisms of action and their therapeutic potential. We discuss whether or not modulating morphogenesis constitutes a strategy to treat Candida infections. PMID:21642508

The ERM protein Moesin is essential for neuronal morphogenesis and long-term memory in Drosophila.

PubMed

Freymuth, Patrick S; Fitzsimons, Helen L

2017-08-29

Moesin is a cytoskeletal adaptor protein that plays an important role in modification of the actin cytoskeleton. Rearrangement of the actin cytoskeleton drives both neuronal morphogenesis and the structural changes in neurons that are required for long-term memory formation. Moesin has been identified as a candidate memory gene in Drosophila, however, whether it is required for memory formation has not been evaluated. Here, we investigate the role of Moesin in neuronal morphogenesis and in short- and long-term memory formation in the courtship suppression assay, a model of associative memory. We found that both knockdown and overexpression of Moesin led to defects in axon growth and guidance as well as dendritic arborization. Moreover, reduction of Moesin expression or expression of a constitutively active phosphomimetic in the adult Drosophila brain had no effect on short term memory, but prevented long-term memory formation, an effect that was independent of its role in development. These results indicate a critical role for Moesin in both neuronal morphogenesis and long-term memory formation.

Growth and morphogenesis of embryonic mouse organs on non-coated and extracellular matrix-coated Biopore membrane

NASA Technical Reports Server (NTRS)

Hardman, P.; Klement, B. J.; Spooner, B. S.

1993-01-01

Embryonic mouse salivary glands, pancreata, and kidneys were isolated from embryos of appropriate gestational age by microdissection, and were cultured on Biopore membrane either non-coated or coated with type I collagen or Matrigel. As expected, use of Biopore membrane allowed high quality photomicroscopy of the living organs. In all organs extensive mesenchymal spreading was observed in the presence of type I collagen or Matrigel. However, differences were noted in the effects of extracellular matrix (ECM) coatings on epithelial growth and morphogenesis: salivary glands were minimally affected, pancreas morphogenesis was adversely affected, and kidney growth and branching apparently was enhanced. It is suggested that these differences in behaviour reflect differences in the strength of interactions between the mesenchymal cells and their surrounding endogenous matrix, compared to the exogenous ECM macromolecules. This method will be useful for culture of these and other embryonic organs. In particular, culture of kidney rudiments on ECM-coated Biopore offers a great improvement over previously used methods which do not allow morphogenesis to be followed in vitro.

Embryologic and Fetal Development of the Human Eyelid

PubMed Central

Abdulhafez, Mohamed H.; Fouad, Yousef A.; Dutton, Jonathan J.

2016-01-01

Purpose: To review the recent data about eyelid morphogenesis, and outline a timeline for eyelid development from the very early stages during embryonic life till final maturation of the eyelid late in fetal life. Methods: The authors extensively review major studies detailing human embryologic and fetal eyelid morphogenesis. These studies span almost a century and include some more recent cadaver studies. Numerous studies in the murine model have helped to better understand the molecular signals that govern eyelid embryogenesis. The authors summarize the current findings in molecular biology, and highlight the most significant studies in mice regarding the multiple and interacting signaling pathways involved in regulating normal eyelid morphogenesis. Results: Eyelid morphogenesis involves a succession of subtle yet strictly regulated morphogenetic episodes of tissue folding, proliferation, contraction, and even migration, which may occur simultaneously or in succession. Conclusions: Understanding the extraordinary process of building eyelid tissue in embryonic life, and deciphering its underlying signaling machinery has far reaching clinical implications beyond understanding the developmental abnormalities involving the eyelids, and may pave the way for achieving scar-reducing therapies in adult mammalian wounds, or control the spread of malignancies. PMID:27124372

Huntingtin Is Required for Epithelial Polarity through RAB11A-Mediated Apical Trafficking of PAR3-aPKC

PubMed Central

Elias, Salah; McGuire, John Russel; Yu, Hua; Humbert, Sandrine

2015-01-01

The establishment of apical-basolateral polarity is important for both normal development and disease, for example, during tumorigenesis and metastasis. During this process, polarity complexes are targeted to the apical surface by a RAB11A-dependent mechanism. Huntingtin (HTT), the protein that is mutated in Huntington disease, acts as a scaffold for molecular motors and promotes microtubule-based dynamics. Here, we investigated the role of HTT in apical polarity during the morphogenesis of the mouse mammary epithelium. We found that the depletion of HTT from luminal cells in vivo alters mouse ductal morphogenesis and lumen formation. HTT is required for the apical localization of PAR3-aPKC during epithelial morphogenesis in virgin, pregnant, and lactating mice. We show that HTT forms a complex with PAR3, aPKC, and RAB11A and ensures the microtubule-dependent apical vesicular translocation of PAR3-aPKC through RAB11A. We thus propose that HTT regulates polarized vesicular transport, lumen formation and mammary epithelial morphogenesis. PMID:25942483

Crk synergizes with epidermal growth factor for epithelial invasion and morphogenesis and is required for the met morphogenic program.

PubMed

Lamorte, Louie; Rodrigues, Sonia; Naujokas, Monica; Park, Morag

2002-10-04

Activation of the Met receptor tyrosine kinase through its ligand, hepatocyte growth factor, stimulates cell spreading, cell dispersal, and the inherent morphogenic program of various epithelial cell lines. Although both hepatocyte growth factor and epidermal growth factor (EGF) can activate downstream signaling pathways in Madin-Darby canine kidney epithelial cells, EGF fails to promote the breakdown of cell-cell junctional complexes and initiate an invasive morphogenic program. We have undertaken a strategy to identify signals that synergize with EGF in this process. We provide evidence that the overexpression of the CrkII adapter protein complements EGF-stimulated pathways to induce cell dispersal in two-dimensional cultures and cell invasion and branching morphogenesis in three-dimensional collagen gels. This finding correlates with the ability of CrkII to promote the breakdown of adherens junctions in stable cell lines and the ability of EGF to stimulate enhanced Rac activity in cells overexpressing CrkII. We have previously shown that the Gab1-docking protein is required for branching morphogenesis downstream of the Met receptor. Consistent with a role for CrkII in promoting EGF-dependent branching morphogenesis, the binding of Gab1 to CrkII is required for the branching morphogenic program downstream of Met. Together, our data support a role for the CrkII adapter protein in epithelial invasion and morphogenesis and underscores the importance of considering the synergistic actions of signaling pathways in cancer progression.

Cell Cycle Dynamics and Quorum Sensing in Candida albicans Chlamydospores Are Distinct from Budding and Hyphal Growth

PubMed Central

Martin, Stephen W.; Douglas, Lois M.; Konopka, James B.

2005-01-01

The regulation of morphogenesis in the human fungal pathogen Candida albicans is under investigation to better understand how the switch between budding and hyphal growth is linked to virulence. Therefore, in this study we examined the ability of C. albicans to undergo a distinct type of morphogenesis to form large thick-walled chlamydospores whose role in infection is unclear, but they act as a resting form in other species. During chlamydospore morphogenesis, cells switch to filamentous growth and then develop elongated suspensor cells that give rise to chlamydospores. These filamentous cells were distinct from true hyphae in that they were wider and were not inhibited by the quorum-sensing factor farnesol. Instead, farnesol increased chlamydospore production, indicating that quorum sensing can also have a positive role. Nuclear division did not occur across the necks of chlamydospores, as it does in budding. Interestingly, nuclei divided within the suspensor cells, and then one daughter nucleus subsequently migrated into the chlamydospore. Septins were not detected near mitotic nuclei but were localized at chlamydospore necks. At later stages, septins localized throughout the chlamydospore plasma membrane and appeared to form long filamentous structures. Deletion of the CDC10 or CDC11 septins caused greater curvature of cells growing in a filamentous manner and morphological defects in suspensor cells and chlamydospores. These studies identify aspects of chlamydospore morphogenesis that are distinct from bud and hyphal morphogenesis. PMID:16002645

Flight feather development: its early specialization during embryogenesis.

PubMed

Kondo, Mao; Sekine, Tomoe; Miyakoshi, Taku; Kitajima, Keiichi; Egawa, Shiro; Seki, Ryohei; Abe, Gembu; Tamura, Koji

2018-01-01

Flight feathers, a type of feather that is unique to extant/extinct birds and some non-avian dinosaurs, are the most evolutionally advanced type of feather. In general, feather types are formed in the second or later generation of feathers at the first and following molting, and the first molting begins at around two weeks post hatching in chicken. However, it has been stated in some previous reports that the first molting from the natal down feathers to the flight feathers is much earlier than that for other feather types, suggesting that flight feather formation starts as an embryonic event. The aim of this study was to determine the inception of flight feather morphogenesis and to identify embryological processes specific to flight feathers in contrast to those of down feathers. We found that the second generation of feather that shows a flight feather-type arrangement has already started developing by chick embryonic day 18, deep in the skin of the flight feather-forming region. This was confirmed by shh gene expression that shows barb pattern, and the expression pattern revealed that the second generation of feather development in the flight feather-forming region seems to start by embryonic day 14. The first stage at which we detected a specific morphology of the feather bud in the flight feather-forming region was embryonic day 11, when internal invagination of the feather bud starts, while the external morphology of the feather bud is radial down-type. The morphogenesis for the flight feather, the most advanced type of feather, has been drastically modified from the beginning of feather morphogenesis, suggesting that early modification of the embryonic morphogenetic process may have played a crucial role in the morphological evolution of this key innovation. Co-optation of molecular cues for axial morphogenesis in limb skeletal development may be able to modify morphogenesis of the feather bud, giving rise to flight feather-specific morphogenesis of traits.

Expression and Functional Role of Sprouty-2 in Breast Morphogenesis

PubMed Central

Hilmarsdottir, Bylgja; Gustafsdottir, Sigrun M.; Franzdottir, Sigridur Rut; Arason, Ari Jon; Steingrimsson, Eirikur; Magnusson, Magnus K.; Gudjonsson, Thorarinn

2013-01-01

Branching morphogenesis is a mechanism used by many species for organogenesis and tissue maintenance. Receptor tyrosine kinases (RTKs), including epidermal growth factor receptor (EGFR) and the sprouty protein family are believed to be critical regulators of branching morphogenesis. The aim of this study was to analyze the expression of Sprouty-2 (SPRY2) in the mammary gland and study its role in branching morphogenesis. Human breast epithelial cells, breast tissue and mouse mammary glands were used for expression studies using immunoblotting, real rime PCR and immunohistochemistry. Knockdown of SPRY2 in the breast epithelial stem cell line D492 was done by lentiviral transduction of shRNA constructs targeting SPRY2. Three dimensional culture of D492 with or without endothelial cells was done in reconstituted basement membrane matrix. We show that in the human breast, SPRY2 is predominantly expressed in the luminal epithelial cells of both ducts and lobuli. In the mouse mammary gland, SPRY2 expression is low or absent in the virgin state, while in the pregnant mammary gland SPRY2 is expressed at branching epithelial buds with increased expression during lactation. This expression pattern is closely associated with the activation of the EGFR pathway. Using D492 which generates branching structures in three-dimensional (3D) culture, we show that SPRY2 expression is low during initiation of branching with subsequent increase throughout the branching process. Immunostaining locates expression of phosphorylated SPRY2 and EGFR at the tip of lobular-like, branching ends. SPRY2 knockdown (KD) resulted in increased migration, increased pERK and larger and more complex branching structures indicating a loss of negative feedback control during branching morphogenesis. In D492 co-cultures with endothelial cells, D492 SPRY2 KD generates spindle-like colonies that bear hallmarks of epithelial to mesenchymal transition. These data indicate that SPRY2 is an important regulator of branching morphogenesis and epithelial to mesenchymal transition in the mammary gland. PMID:23573284

Expression and functional role of sprouty-2 in breast morphogenesis.

PubMed

Sigurdsson, Valgardur; Ingthorsson, Saevar; Hilmarsdottir, Bylgja; Gustafsdottir, Sigrun M; Franzdottir, Sigridur Rut; Arason, Ari Jon; Steingrimsson, Eirikur; Magnusson, Magnus K; Gudjonsson, Thorarinn

2013-01-01

Branching morphogenesis is a mechanism used by many species for organogenesis and tissue maintenance. Receptor tyrosine kinases (RTKs), including epidermal growth factor receptor (EGFR) and the sprouty protein family are believed to be critical regulators of branching morphogenesis. The aim of this study was to analyze the expression of Sprouty-2 (SPRY2) in the mammary gland and study its role in branching morphogenesis. Human breast epithelial cells, breast tissue and mouse mammary glands were used for expression studies using immunoblotting, real rime PCR and immunohistochemistry. Knockdown of SPRY2 in the breast epithelial stem cell line D492 was done by lentiviral transduction of shRNA constructs targeting SPRY2. Three dimensional culture of D492 with or without endothelial cells was done in reconstituted basement membrane matrix. We show that in the human breast, SPRY2 is predominantly expressed in the luminal epithelial cells of both ducts and lobuli. In the mouse mammary gland, SPRY2 expression is low or absent in the virgin state, while in the pregnant mammary gland SPRY2 is expressed at branching epithelial buds with increased expression during lactation. This expression pattern is closely associated with the activation of the EGFR pathway. Using D492 which generates branching structures in three-dimensional (3D) culture, we show that SPRY2 expression is low during initiation of branching with subsequent increase throughout the branching process. Immunostaining locates expression of phosphorylated SPRY2 and EGFR at the tip of lobular-like, branching ends. SPRY2 knockdown (KD) resulted in increased migration, increased pERK and larger and more complex branching structures indicating a loss of negative feedback control during branching morphogenesis. In D492 co-cultures with endothelial cells, D492 SPRY2 KD generates spindle-like colonies that bear hallmarks of epithelial to mesenchymal transition. These data indicate that SPRY2 is an important regulator of branching morphogenesis and epithelial to mesenchymal transition in the mammary gland.

Biomaterial Selection for Tooth Regeneration

PubMed Central

Yuan, Zhenglin; Nie, Hemin; Wang, Shuang; Lee, Chang Hun; Li, Ang; Fu, Susan Y.; Zhou, Hong

2011-01-01

Biomaterials are native or synthetic polymers that act as carriers for drug delivery or scaffolds for tissue regeneration. When implanted in vivo, biomaterials should be nontoxic and exert intended functions. For tooth regeneration, biomaterials have primarily served as a scaffold for (1) transplanted stem cells and/or (2) recruitment of endogenous stem cells. This article critically synthesizes our knowledge of biomaterial use in tooth regeneration, including the selection of native and/or synthetic polymers, three-dimensional scaffold fabrication, stem cell transplantation, and stem cell homing. A tooth is a complex biological organ. Tooth loss represents the most common organ failure. Tooth regeneration encompasses not only regrowth of an entire tooth as an organ, but also biological restoration of individual components of the tooth including enamel, dentin, cementum, or dental pulp. Regeneration of tooth root represents perhaps more near-term opportunities than the regeneration of the whole tooth. In the adult, a tooth owes its biological vitality, arguably more, to the root than the crown. Biomaterials are indispensible for the regeneration of tooth root, tooth crown, dental pulp, or an entire tooth. PMID:21699433

Tumour compartment transcriptomics demonstrates the activation of inflammatory and odontogenic programmes in human adamantinomatous craniopharyngioma and identifies the MAPK/ERK pathway as a novel therapeutic target.

PubMed

Apps, John R; Carreno, Gabriela; Gonzalez-Meljem, Jose Mario; Haston, Scott; Guiho, Romain; Cooper, Julie E; Manshaei, Saba; Jani, Nital; Hölsken, Annett; Pettorini, Benedetta; Beynon, Robert J; Simpson, Deborah M; Fraser, Helen C; Hong, Ying; Hallang, Shirleen; Stone, Thomas J; Virasami, Alex; Donson, Andrew M; Jones, David; Aquilina, Kristian; Spoudeas, Helen; Joshi, Abhijit R; Grundy, Richard; Storer, Lisa C D; Korbonits, Márta; Hilton, David A; Tossell, Kyoko; Thavaraj, Selvam; Ungless, Mark A; Gil, Jesus; Buslei, Rolf; Hankinson, Todd; Hargrave, Darren; Goding, Colin; Andoniadou, Cynthia L; Brogan, Paul; Jacques, Thomas S; Williams, Hywel J; Martinez-Barbera, Juan Pedro

2018-05-01

Adamantinomatous craniopharyngiomas (ACPs) are clinically challenging tumours, the majority of which have activating mutations in CTNNB1. They are histologically complex, showing cystic and solid components, the latter comprised of different morphological cell types (e.g. β-catenin-accumulating cluster cells and palisading epithelium), surrounded by a florid glial reaction with immune cells. Here, we have carried out RNA sequencing on 18 ACP samples and integrated these data with an existing ACP transcriptomic dataset. No studies so far have examined the patterns of gene expression within the different cellular compartments of the tumour. To achieve this goal, we have combined laser capture microdissection with computational analyses to reveal groups of genes that are associated with either epithelial tumour cells (clusters and palisading epithelium), glial tissue or immune infiltrate. We use these human ACP molecular signatures and RNA-Seq data from two ACP mouse models to reveal that cell clusters are molecularly analogous to the enamel knot, a critical signalling centre controlling normal tooth morphogenesis. Supporting this finding, we show that human cluster cells express high levels of several members of the FGF, TGFB and BMP families of secreted factors, which signal to neighbouring cells as evidenced by immunostaining against the phosphorylated proteins pERK1/2, pSMAD3 and pSMAD1/5/9 in both human and mouse ACP. We reveal that inhibiting the MAPK/ERK pathway with trametinib, a clinically approved MEK inhibitor, results in reduced proliferation and increased apoptosis in explant cultures of human and mouse ACP. Finally, we analyse a prominent molecular signature in the glial reactive tissue to characterise the inflammatory microenvironment and uncover the activation of inflammasomes in human ACP. We validate these results by immunostaining against immune cell markers, cytokine ELISA and proteome analysis in both solid tumour and cystic fluid from ACP patients. Our data support a new molecular paradigm for understanding ACP tumorigenesis as an aberrant mimic of natural tooth development and opens new therapeutic opportunities by revealing the activation of the MAPK/ERK and inflammasome pathways in human ACP.

Alteration in the ultrastructural morphology of mycelial hyphae and the dynamics of transcriptional activity of lytic enzyme genes during basidiomycete morphogenesis.

PubMed

Vetchinkina, Elena; Kupryashina, Maria; Gorshkov, Vladimir; Ageeva, Marina; Gogolev, Yuri; Nikitina, Valentina

2017-04-01

The morphogenesis of macromycetes is a complex multilevel process resulting in a set of molecular-genetic, physiological-biochemical, and morphological-ultrastructural changes in the cells. When the xylotrophic basidiomycetes Lentinus edodes, Grifola frondosa, and Ganoderma lucidum were grown on wood waste as the substrate, the ultrastructural morphology of the mycelial hyphal cell walls differed considerably between mycelium and morphostructures. As the macromycetes passed from vegetative to generative development, the expression of the tyr1, tyr2, chi1, chi2, exg1, exg2, and exg3 genes was activated. These genes encode enzymes such as tyrosinase, chitinase, and glucanase, which play essential roles in cell wall growth and morphogenesis.

Computational models of airway branching morphogenesis.

PubMed

Varner, Victor D; Nelson, Celeste M

2017-07-01

The bronchial network of the mammalian lung consists of millions of dichotomous branches arranged in a highly complex, space-filling tree. Recent computational models of branching morphogenesis in the lung have helped uncover the biological mechanisms that construct this ramified architecture. In this review, we focus on three different theoretical approaches - geometric modeling, reaction-diffusion modeling, and continuum mechanical modeling - and discuss how, taken together, these models have identified the geometric principles necessary to build an efficient bronchial network, as well as the patterning mechanisms that specify airway geometry in the developing embryo. We emphasize models that are integrated with biological experiments and suggest how recent progress in computational modeling has advanced our understanding of airway branching morphogenesis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Polarized protein transport and lumen formation during epithelial tissue morphogenesis.

PubMed

Blasky, Alex J; Mangan, Anthony; Prekeris, Rytis

2015-01-01

One of the major challenges in biology is to explain how complex tissues and organs arise from the collective action of individual polarized cells. The best-studied model of this process is the cross talk between individual epithelial cells during their polarization to form the multicellular epithelial lumen during tissue morphogenesis. Multiple mechanisms of apical lumen formation have been proposed. Some epithelial lumens form from preexisting polarized epithelial structures. However, de novo lumen formation from nonpolarized cells has recently emerged as an important driver of epithelial tissue morphogenesis, especially during the formation of small epithelial tubule networks. In this review, we discuss the latest findings regarding the mechanisms and regulation of de novo lumen formation in vitro and in vivo.

Morphogenesis and gravity in a whole amphibian embryo and in isolated blastomeres of sea urchins.

PubMed

Izumi-Kurotani, Akemi; Kiyomoto, Masato

2003-01-01

Fertilization and subsequent embryogenesis of newts occurred normally under microgravity in two Astronewt flight experiments. By accumulation of the results from the amphibian flight experiments including 'Astronewt', it is considered that gravity has rather small effects on the early development of amphibian eggs. However, some temporary abnormalities, which recover in the course of the further developmental process, have been observed. Some regulations may occur in whole embryos. For a thorough knowledge about the role of gravity in morphogenesis, we need to investigate the gravitational effects on a single cell in a whole embryo. We propose a new experimental system with sea urchin embryos and micromeres for further studies at a cellular level of the effects of gravity on morphogenesis.

To grow or not to grow: hair morphogenesis and human genetic hair disorders.

PubMed

Duverger, Olivier; Morasso, Maria I

2014-01-01

Mouse models have greatly helped in elucidating the molecular mechanisms involved in hair formation and regeneration. Recent publications have reviewed the genes involved in mouse hair development based on the phenotype of transgenic, knockout and mutant animal models. While much of this information has been instrumental in determining molecular aspects of human hair development and cycling, mice exhibit a specific pattern of hair morphogenesis and hair distribution throughout the body that cannot be directly correlated to human hair. In this mini-review, we discuss specific aspects of human hair follicle development and present an up-to-date summary of human genetic disorders associated with abnormalities in hair follicle morphogenesis, structure or regeneration. Published by Elsevier Ltd.

A novel ALS-associated variant in UBQLN4 regulates motor axon morphogenesis.

PubMed

Edens, Brittany M; Yan, Jianhua; Miller, Nimrod; Deng, Han-Xiang; Siddique, Teepu; Ma, Yongchao C

2017-05-02

The etiological underpinnings of amyotrophic lateral sclerosis (ALS) are complex and incompletely understood, although contributions to pathogenesis by regulators of proteolytic pathways have become increasingly apparent. Here, we present a novel variant in UBQLN4 that is associated with ALS and show that its expression compromises motor axon morphogenesis in mouse motor neurons and in zebrafish. We further demonstrate that the ALS-associated UBQLN4 variant impairs proteasomal function, and identify the Wnt signaling pathway effector beta-catenin as a UBQLN4 substrate. Inhibition of beta-catenin function rescues the UBQLN4 variant-induced motor axon phenotypes. These findings provide a strong link between the regulation of axonal morphogenesis and a new ALS-associated gene variant mediated by protein degradation pathways.

From The Cover: Reconstruction of functionally normal and malignant human breast tissues in mice

NASA Astrophysics Data System (ADS)

Kuperwasser, Charlotte; Chavarria, Tony; Wu, Min; Magrane, Greg; Gray, Joe W.; Carey, Loucinda; Richardson, Andrea; Weinberg, Robert A.

2004-04-01

The study of normal breast epithelial morphogenesis and carcinogenesis in vivo has largely used rodent models. Efforts at studying mammary morphogenesis and cancer with xenotransplanted human epithelial cells have failed to recapitulate the full extent of development seen in the human breast. We have developed an orthotopic xenograft model in which both the stromal and epithelial components of the reconstructed mammary gland are of human origin. Genetic modification of human stromal cells before the implantation of ostensibly normal human mammary epithelial cells resulted in the outgrowth of benign and malignant lesions. This experimental model allows for studies of human epithelial morphogenesis and differentiation in vivo and underscores the critical role of heterotypic interactions in human breast development and carcinogenesis.

Apoptosis in Early Salivary Gland Duct Morphogenesis and Lumen Formation.

PubMed

Teshima, T H N; Wells, K L; Lourenço, S V; Tucker, A S

2016-03-01

Salivary glands are essential for the maintenance of oral health by providing lubrication and antimicrobial protection to the mucosal and tooth surfaces. Saliva is modified and delivered to the oral cavity by a complex multifunctional ductal system. During development, these ducts form as solid tubes, which undergo cavitation to create lumens. Apoptosis has been suggested to play a role in this cavitation process along with changes in cell polarity. Here, we show that apoptosis occurs from the very earliest stages of mouse salivary gland development, much earlier than previously reported. Apoptotic cells were observed in the center of the first epithelial stalk at early-stage embryonic day 12.5 (E12.5) according to both TUNEL staining and cleaved caspase 3 immunofluorescence. The presumptive lumen space was highlighted by the colocalization of a predictive lumen marker, cytokeratin 7. At E14.5, as lumens start to form throughout the glands, apoptotic expression decreased while cytokeratin 7 remained positive. In vitro inhibition of all caspases in E12.5 and E13.5 salivary glands resulted in wider ducts, as compared with the controls, and a defect in lumen formation. In contrast, no such defect in lumen formation was observed at E14.5. Our data indicate that apoptosis is involved during early stages of gland formation (E12.5 onward) and appears important for shaping the forming ducts. © International & American Associations for Dental Research 2015.

Enamel protein regulation and dental and periodontal physiopathology in MSX2 mutant mice.

PubMed

Molla, Muriel; Descroix, Vianney; Aïoub, Muhanad; Simon, Stéphane; Castañeda, Beatriz; Hotton, Dominique; Bolaños, Alba; Simon, Yohann; Lezot, Frédéric; Goubin, Gérard; Berdal, Ariane

2010-11-01

Signaling pathways that underlie postnatal dental and periodontal physiopathology are less studied than those of early tooth development. Members of the muscle segment homeobox gene (Msx) family encode homeoproteins that show functional redundancy during development and are known to be involved in epithelial-mesenchymal interactions that lead to crown morphogenesis and ameloblast cell differentiation. This study analyzed the MSX2 protein during mouse postnatal growth as well as in the adult. The analysis focused on enamel and periodontal defects and enamel proteins in Msx2-null mutant mice. In the epithelial lifecycle, the levels of MSX2 expression and enamel protein secretion were inversely related. Msx2+/- mice showed increased amelogenin expression, enamel thickness, and rod size. Msx2-/- mice displayed compound phenotypic characteristics of enamel defects, related to both enamel-specific gene mutations (amelogenin and enamelin) in isolated amelogenesis imperfecta, and cell-cell junction elements (laminin 5 and cytokeratin 5) in other syndromes. These effects were also related to ameloblast disappearance, which differed between incisors and molars. In Msx2-/- roots, Malassez cells formed giant islands that overexpressed amelogenin and ameloblastin that grew over months. Aberrant expression of enamel proteins is proposed to underlie the regional osteopetrosis and hyperproduction of cellular cementum. These enamel and periodontal phenotypes of Msx2 mutants constitute the first case report of structural and signaling defects associated with enamel protein overexpression in a postnatal context.

The prevalence of tooth discolouration and the self-satisfaction with tooth colour in a Chinese urban population.

PubMed

Xiao, J; Zhou, X D; Zhu, W C; Zhang, B; Li, J Y; Xu, X

2007-05-01

To determine the prevalence of tooth discolouration, self-satisfaction with tooth colour, and correlation with socio-demographic-behavioural factors in adults and teenagers in Chengdu, China. A cross-sectional survey. 405 Chinese urban adults and teenagers from a multistage random probability sample. Tooth colour was measured on the maxillary central incisors using a colorimeter. Tooth discolouration was determined according to the discolouration level figure and evaluation criteria. Self-satisfaction with tooth colour was assessed on a five-point qualitative scale. Data were coded and analyzed using SPSS software. The mean values for L*, a* and b* were 70.67 (s.d. 1.91), 4.29 (s.d. 2.05) and 17.51 (s.d. 4.13), respectively. Age and sex were the most important factors associated with tooth colour (P < 0.05). About half of the study population (48.9%) suffered from some tooth discolouration, and 52.6% were dissatisfied with their tooth colour. Education and smoking were significant factors affecting self-satisfaction with tooth colour (P < 0.05). Tooth discolouration is common among the Chinese, and many Chinese are dissatisfied with their tooth colour. Self-satisfaction with tooth colour decreased with increasing severity of discolouration. Further research is needed to determine types of tooth discolouration among broader regions in China.

[Effect of a tooth-brushing education program on oral health of preschool children].

PubMed

Kang, Bok-Hee; Park, Sun-Nam; Sohng, Kyeong-Yae; Moon, Jung-Soon

2008-12-01

To examine the effect of tooth-brushing education on the oral health of preschoolers. A quasi-experimental design with a non-equivalent control group was used. Two kindergartens were selected and 39 preschoolers from one kindergarten were assigned to the experimental group with tooth-brushing education and 39 from the other kindergarten to the control group. The tooth-brushing education program included 1 session on oral health education, individual tooth-brushing instruction for 1 week and supervised tooth-brushing after lunch for 4 weeks. Oral health behavior including use of tooth paste, tooth-brushing time and method of tooth-brushing, plague, streptococcus mutans, lactobacillus and dental caries were measured before and after the education. Fisher's exact test, t-test and paired t-test with the Window SAS 9.1 program were used to analyze the data. A significant increase in the use of tooth paste, tooth-brushing time and the practice of correct tooth-brushing and a decrease in plague and development of dental caries were observed in the experimental group. This tooth-brushing education was partially effective in improving oral health of preschoolers.

Evaluation of an experimental rat model for comparative studies of bleaching agents.

PubMed

Cintra, Luciano Tavares Angelo; Benetti, Francine; Ferreira, Luciana Lousada; Rahal, Vanessa; Ervolino, Edilson; Jacinto, Rogério de Castilho; Gomes Filho, João Eduardo; Briso, André Luiz Fraga

2016-01-01

Dental materials, in general, are tested in different animal models prior to their clinical use in humans, except for bleaching agents. To evaluate an experimental rat model for comparative studies of bleaching agents by investigating the influence of different concentrations and application times of H2O2 gel in the pulp tissue during in-office bleaching of rats' vital teeth. The right and left maxillary molars of 50 Wistar rats were bleached with 20% and 35% H2O2 gels, respectively, for 5, 10, 15, 30, or 45 min (n=10 rats/group). Ten animals (control) were untreated. The rats were killed after 2 or 30 days, and the maxillae were examined by light microscopy. Inflammation was evaluated by histomorphometric analysis with inflammatory cell counting in the coronal and radicular thirds of the pulp. The counting of fibroblasts was also performed. Scores were attributed to the odontoblastic layer and to vascular changes. The tertiary dentin area and the pulp chamber central area were histomorphometrically measured. Data were compared by the analysis of variance and the Kruskal-Wallis test (p<0.05). After 2 days, the amount of inflammatory cells increased in the occlusal third of the coronal pulp until the time of 15 min for both concentrations of bleaching gels. In 30 and 45 min groups of each concentration, the number of inflammatory cells decreased along with the appearance of necrotic areas. After 30 days, a reduction in the pulp chamber central area and an enlargement of tertiary dentin area were observed without the detection of inflammation areas. The rat model of extra coronal bleaching showed to be adequate for bleaching protocols studies, as it was possible to observe alterations in the pulp tissues and in the tooth structure caused by different concentrations and periods of application of bleaching agents.

Mechanical stress regulates osteogenic differentiation and RANKL/OPG ratio in periodontal ligament stem cells by the Wnt/β-catenin pathway.

PubMed

Zhang, Liqiang; Liu, Wenjia; Zhao, Jiangdong; Ma, Xiaojie; Shen, Lin; Zhang, Yongjie; Jin, Fang; Jin, Yan

2016-10-01

The balance between osteoblastic and osteoclastic activity is critical in orthodontic tooth movement (OTM). Mesenchymal stem cells (MSCs) play an important role in maintaining bone homeostasis, and periodontal ligament stem cells (PDLSCs) are tissue-specific MSCs in the periodontal ligament. However, whether PDLSCs are required for periodontal tissue remodeling during OTM is not fully understood. Here, we used PDGFRα and Nestin to trace PDLSCs during OTM in rats. We treat human PDLSCs with 100kpa static pressure for 1h or 12h in vitro, and examined the phenotypic changes and expression of RANKL and OPG in these cells. In vivo, we found that positive signals of PDGFRα and Nestin in the PDL gradually increased and then decreased on the pressure side to which pressure was applied. In vitro, the osteogenic differentiation of PDLSCs was significantly increased after force treatment for 1h relative to 12h. In contrast, the expression ratio of RANKL/OPG was reduced at 1h and significantly increased at 12h. Furthermore, we found that the Wnt/β-catenin pathway was dynamically activated in the PDL and in PDLSCs after mechanical stimulation. Importantly, the canonical Wnt pathway inhibitor DKK1 blocked the osteogenesis effect and rescued the ratio of RANKL/OPG in PDLSCs under force treatment for 1h. Our findings reveal that PDLSCs participate in OTM and that the Wnt/β-catenin pathway maintains bone homeostasis during tooth movement by regulating the balance between osteoblastic and osteoclastic activity. We describe a novel potential mechanism related to tooth movement. Copyright © 2016 Elsevier B.V. All rights reserved.

Chronological gene expression of parathyroid hormone-related protein (PTHrP) in the stellate reticulum of the rat: implications for tooth eruption.

PubMed

Yao, Shaomian; Pan, Fenghui; Wise, Gary E

2007-03-01

Tooth eruption is a localized event that requires the expression of certain molecules at precise times to regulate bone resorption and bone formation. Parathyroid hormone-related protein (PTHrP) may be one of those molecules. Although PTHrP is produced in the stellate reticulum (SR) of the tooth and exerts its effect on the adjacent dental follicle, its expression pattern in the SR is unknown. Thus, it was the objectives of this study to determine the chronology of expression of PTHrP, and then to determine its effect on vascular endothelial growth factor (VEGF) expression for osteoclastogenesis and on bone morphogenetic protein-2 (BMP-2) for bone growth. Laser capture microdissection and RT-PCR were used to determine the chronological expression of PTHrP in vivo. In vitro, dental follicle cells were incubated with PTHrP and RT-PCR was conducted to determine its effect on VEGF and BMP-2 gene expression. PTHrP was maximally expressed at day 7 postnatally in the SR with the level of expression still high at day 9. In vitro, PTHrP upregulated VEGF120 and VEGF164 expression after 4h of incubation with a maximum effect at 6h. PTHrP upregulated BMP-2 gene expression with a maximal effect at 2h. Because the secondary burst of osteoclastogenesis needed for eruption occurs around day 10, it is possible that PTHrP is stimulating this osteoclastogenesis by upregulating VEGF. Concurrently, the upregulation of BMP-2 by PTHrP may stimulate bone growth at the base of the bony crypt to promote eruption.

IL-8 and MCP-1 induced by excessive orthodontic force mediates odontoclastogenesis in periodontal tissues.

PubMed

Asano, M; Yamaguchi, M; Nakajima, R; Fujita, S; Utsunomiya, T; Yamamoto, H; Kasai, K

2011-07-01

The aim of this study was to investigate how interleukin (IL)-8 (cytokine-induced neutrophil chemoattractant; CINC-1) and monocyte chemotactic protein (MCP)-1/CCL2 contribute to root resorption during orthodontic tooth movement. Forty 6-week-old male Wistar rats were subjected to orthodontic force of 10 or 50 g to induce a mesially tipping movement of the upper first molars for 7 days. We determined the expressions of CINC-1, CXCR2, and MCP-1 proteins in root resorption area using immunohistochemistry. Furthermore, we investigated the effects of compression forces (CF) on IL-8 and MCP-1 production by human periodontal ligament (hPDL) cells. We observed an effect of chemokine treatment on rat odonto/osteoclasts in dentin slices that recapitulated root resorption. The immunoreactivity for CINC-1/CXCR2 and MCP-1 was detected in odontoclasts and PDL fibroblasts by the orthodontic force of 50 g on day 7. CF increased the secretion and the expression of mRNA of IL-8 and MCP-1 from PDL cells in a magnitude-dependent manner. Moreover, CINC-1 and MCP-1 stimulated osteoclastogenesis from rat osteoclast precursor cells. IL-8 (CINC-1) and MCP-1 may therefore facilitate the process of root resorption because of excessive orthodontic force. © 2010 John Wiley & Sons A/S.

Nifedipine-induced gingival overgrowth in rats: brief review and experimental study.

PubMed

Fu, E; Nieh, S; Hsiao, C T; Hsieh, Y D; Wikesjö, U M; Shen, E C

1998-07-01

The first case report of gingival overgrowth induced by nifedipine (NIF), a calcium-beta blocker, was in 1984. However, the association between gingival alterations and the drug therapy of sodium diphenyl hydantoinate was initially described in 1939. The purpose of the experimental study was to examine the effect of NIF on gingival morphology in an animal model. Forty-five male Sprague-Dawley rats were randomly divided into 3 groups. Animals in each group daily received NIF in dimethyl sulfoxide by gastric feeding at a dosage of 0 (control), 30, or 50 mg/kg body weight for 9 weeks. Gingival gross morphology was assessed tri-weekly from stone models obtained from the mandibular incisal region. Animals were sacrificed at the end of study and tissue blocks were processed for histopathologic and histometric evaluation. Histometric analysis was performed at 5 selected tissue levels. Macro- and microscopic significantly increased gingival dimensions were demonstrated in NIF-treated animals compared to control. Although a fibrovascular tissue was observed in the tooth-gingiva interface for both NIF-treated and control animals, it was thicker and appeared earlier in NIF-treated animals. The results of the present study suggest that gingival overgrowth can be induced by NIF in rats and that the gingival overgrowth appears dose dependent.

Synaptic protein changes after a chronic period of sensorimotor perturbation in adult rats: a potential role of phosphorylation/O-GlcNAcylation interplay.

PubMed

Fourneau, Julie; Canu, Marie-Hélène; Cieniewski-Bernard, Caroline; Bastide, Bruno; Dupont, Erwan

2018-05-28

In human, a chronic sensorimotor perturbation (SMP) through prolonged body immobilization alters motor task performance through a combination of peripheral and central factors. Studies performed on a rat model of SMP have shown biomolecular changes and a reorganization of sensorimotor cortex through events such as morphological modifications of dendritic spines (number, length, functionality). However, underlying mechanisms are still unclear. It is well known that phosphorylation regulates a wide field of synaptic activity leading to neuroplasticity. Another post-translational modification that interplays with phosphorylation is O-GlcNAcylation. This atypical glycosylation, reversible and dynamic, is involved in essential cellular and physiological processes such as synaptic activity, neuronal morphogenesis, learning and memory. We examined potential roles of phosphorylation/O-GlcNAcylation interplay in synaptic plasticity within rat sensorimotor cortex after a SMP period. For this purpose, sensorimotor cortex synaptosomes were separated by sucrose gradient, in order to isolate a subcellular compartment enriched in proteins involved in synaptic functions. A period of SMP induced plastic changes at the pre- and postsynaptic levels, characterized by a reduction of phosphorylation (synapsin1, AMPAR GluA2) and expression (synaptophysin, PSD-95, AMPAR GluA2) of synaptic proteins, as well as a decrease in MAPK/ERK42 activation. Expression levels of OGT/OGA enzymes was unchanged but we observed a specific reduction of synapsin1 O-GlcNAcylation in sensorimotor cortex synaptosomes. The synergistic regulation of synapsin1 phosphorylation/O-GlcNAcylation could affect presynaptic neurotransmitter release. Associated with other pre- and postsynaptic changes, synaptic efficacy could be impaired in somatosensory cortex of SMP rat. Thus, synapsin1 O-GlcNAcylation/phosphorylation interplay also appears to be involved in this synaptic plasticity by finely regulating neural activity. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Tissue-specific activities of the Fat1 cadherin cooperate to control neuromuscular morphogenesis

PubMed Central

2018-01-01

Muscle morphogenesis is tightly coupled with that of motor neurons (MNs). Both MNs and muscle progenitors simultaneously explore the surrounding tissues while exchanging reciprocal signals to tune their behaviors. We previously identified the Fat1 cadherin as a regulator of muscle morphogenesis and showed that it is required in the myogenic lineage to control the polarity of progenitor migration. To expand our knowledge on how Fat1 exerts its tissue-morphogenesis regulator activity, we dissected its functions by tissue-specific genetic ablation. An emblematic example of muscle under such morphogenetic control is the cutaneous maximus (CM) muscle, a flat subcutaneous muscle in which progenitor migration is physically separated from the process of myogenic differentiation but tightly associated with elongating axons of its partner MNs. Here, we show that constitutive Fat1 disruption interferes with expansion and differentiation of the CM muscle, with its motor innervation and with specification of its associated MN pool. Fat1 is expressed in muscle progenitors, in associated mesenchymal cells, and in MN subsets, including the CM-innervating pool. We identify mesenchyme-derived connective tissue (CT) as a cell type in which Fat1 activity is required for the non–cell-autonomous control of CM muscle progenitor spreading, myogenic differentiation, motor innervation, and for motor pool specification. In parallel, Fat1 is required in MNs to promote their axonal growth and specification, indirectly influencing muscle progenitor progression. These results illustrate how Fat1 coordinates the coupling of muscular and neuronal morphogenesis by playing distinct but complementary actions in several cell types. PMID:29768404

Tissue stiffening coordinates morphogenesis by triggering collective cell migration in vivo.

PubMed

Barriga, Elias H; Franze, Kristian; Charras, Guillaume; Mayor, Roberto

2018-02-22

Collective cell migration is essential for morphogenesis, tissue remodelling and cancer invasion. In vivo, groups of cells move in an orchestrated way through tissues. This movement involves mechanical as well as molecular interactions between cells and their environment. While the role of molecular signals in collective cell migration is comparatively well understood, how tissue mechanics influence collective cell migration in vivo remains unknown. Here we investigated the importance of mechanical cues in the collective migration of the Xenopus laevis neural crest cells, an embryonic cell population whose migratory behaviour has been likened to cancer invasion. We found that, during morphogenesis, the head mesoderm underlying the cephalic neural crest stiffens. This stiffening initiates an epithelial-to-mesenchymal transition in neural crest cells and triggers their collective migration. To detect changes in their mechanical environment, neural crest cells use mechanosensation mediated by the integrin-vinculin-talin complex. By performing mechanical and molecular manipulations, we show that mesoderm stiffening is necessary and sufficient to trigger neural crest migration. Finally, we demonstrate that convergent extension of the mesoderm, which starts during gastrulation, leads to increased mesoderm stiffness by increasing the cell density underneath the neural crest. These results show that convergent extension of the mesoderm has a role as a mechanical coordinator of morphogenesis, and reveal a link between two apparently unconnected processes-gastrulation and neural crest migration-via changes in tissue mechanics. Overall, we demonstrate that changes in substrate stiffness can trigger collective cell migration by promoting epithelial-to-mesenchymal transition in vivo. More broadly, our results raise the idea that tissue mechanics combines with molecular effectors to coordinate morphogenesis.

Ylpex5 mutation partially suppresses the defective hyphal growth of a Yarrowia lipolytica ceramide synthase mutant, Yllac1, by recovering lipid raft polarization and vacuole morphogenesis.

PubMed

Bal, Jyotiranjan; Lee, Hye-Jeong; Cheon, Seon Ah; Lee, Kyung Jin; Oh, Doo-Byoung; Kim, Jeong-Yoon

2013-01-01

Sphingolipids are involved in cell differentiation and morphogenesis in eukaryotic cells. In this study, YlLac1p, a ceramide synthase required for glucosylceramide (GlcCer) synthesis, was found to be essential for hyphal growth in Yarrowia lipolytica. Y. lipolytica GlcCer was shown to be composed of a C16:0 fatty acid, which is hydroxylated at C2, and a C18:2 long chain base, which is unsaturated at both C4 and C8 and methylated at C9. Domain swapping analysis revealed that the entire TRAM/Lag1/CLN8 (TLC) domain, not the Lag1 motif, is crucial for the function of YlLac1p. YlDes1p, the C4 desaturase of the ceramide synthesized by YlLac1p, was also required for Y. lipolytica morphogenesis. Both Yllac1Δ and Yldes1Δ mutants neither polarize lipid rafts nor form normal vacuoles. Interestingly, mutation in YlPEX5, which encode a peroxisomal targeting signal receptor, partially suppressed the defective hyphal growth of Yllac1Δ. The Yllac1ΔYlpex5Δ mutant restored the ability to polarize lipid rafts and to form normal vacuoles, although it could not synthesize GlcCer. Taken together, our results suggest that GlcCer or GlcCer derivatives may be involved in hyphal morphogenesis in Y. lipolytica, at least in part, by affecting polarization of lipid rafts and vacuole morphogenesis. Copyright © 2012 Elsevier Inc. All rights reserved.

Exposure to Sodium Fluoride Produces Signs of Apoptosis in Rat Leukocytes

PubMed Central

Gutiérrez-Salinas, José; Morales-González, José A.; Madrigal-Santillán, Eduardo; Esquivel-Soto, Jaime; Esquivel-Chirino, César; González-Rubio, Manuel García-Luna y; Suástegui-Domínguez, Sigrit; Valadez-Vega, Carmen

2010-01-01

Fluoride is naturally present in the earth’s crust and can be found in rocks, coal, and clay; thus, it can be found in small quantities in water, air, plants, and animals. Therefore, humans are exposed to fluoride through food, drinking water, and in the air they breathe. Flouride is essential to maintain bone strength and to protect against dental decay, but if it is absorbed too frequently, it can cause tooth decay, osteoporosis, and damage to kidneys, bones, nerves, and muscles. Therefore, the present work was aimed at determining the effect of intake of sodium fluoride (NaF) as an apoptosis inducer in leukocytes of rats treated for eight weeks with 1 or 50 parts per million (ppm) NaF. Expression of p53, bcl-2, and caspade-3 were used as apoptotic and general metabolism indicators of leukocyte-like indicators of the (INT) oxidation system. Male rats were exposed to NaF (1 and 500 ppm) for eight weeks, and then sacrificed weekly to obtain blood samples. Expression of p53, bcl-2, and caspase-3 were determined in leukocytes by Western blot, and general metabolism of leukocytes was analyzed with a commercial kit. We found changes in the expression of the proteins described, especially when the animals received 50 ppm of NaF. These results indicate that NaF intoxication can be an apoptosis inducer in rat leukocytes treated with the compound for eight weeks. PMID:20957113

[Tooth wear, a proposal for an evaluation system].

PubMed

Wetselaar, P; van der Zaag, J; Lobbezoo, F

2011-06-01

The present-day terminology and definitions of tooth wear are not unambiguous. For diagnosing tooth wear, however, it is essential that they are unambiguous. In this article a proposal is presented for a tooth wear evaluation system with simplified definitions. This system consists ofa number of modules and can be used for various aspects of the diagnostic procedure. It can be used for the quantification of tooth wear, both for periodic screening and for the monitoring of tooth wear in individual patients. The scoring of occlusal/incisal tooth wear as well as of non-occlusal/non-incisal tooth wear is possible. The evaluative system is also suitable for determining which type of tooth wear, such as attrition, abrasion and erosion, is most likely to have caused any observed loss of hard tooth tissue.

Multidisciplinary Inquiry-Based Investigation Learning Using an Ex Ovo Chicken Culture Platform: Role of Vitamin A on Embryonic Morphogenesis

ERIC Educational Resources Information Center

Buskohl, Philip R.; Gould, Russell A.; Curran, Susan; Archer, Shivaun D.; Butcher, Jonathan T.

2012-01-01

Embryonic development offers a unique perspective on the function of many biological processes because of embryos' heightened sensitivity to environmental factors. This hands-on lesson investigates the effects of elevated vitamin A on the morphogenesis of chicken embryos. The active form of vitamin A (retinoic acid) is applied to shell-less (ex…

Epithelial organization and cyst lumen expansion require efficient Sec13-Sec31-driven secretion.

PubMed

Townley, Anna K; Schmidt, Katy; Hodgson, Lorna; Stephens, David J

2012-02-01

Epithelial morphogenesis is directed by interactions with the underlying extracellular matrix. Secretion of collagen and other matrix components requires efficient coat complex II (COPII) vesicle formation at the endoplasmic reticulum. Here, we show that suppression of the outer layer COPII component, Sec13, in zebrafish embryos results in a disorganized gut epithelium. In human intestinal epithelial cells (Caco-2), Sec13 depletion causes defective epithelial polarity and organization on permeable supports. Defects are seen in the ability of cells to adhere to the substrate, form a monolayer and form intercellular junctions. When embedded in a three-dimensional matrix, Sec13-depleted Caco-2 cells form cysts but, unlike controls, are defective in lumen expansion. Incorporation of primary fibroblasts within the three-dimensional culture substantially restores normal morphogenesis. We conclude that efficient COPII-dependent secretion, notably assembly of Sec13-Sec31, is required to drive epithelial morphogenesis in both two- and three-dimensional cultures in vitro, as well as in vivo. Our results provide insight into the role of COPII in epithelial morphogenesis and have implications for the interpretation of epithelial polarity and organization assays in cell culture.

Epithelial organization and cyst lumen expansion require efficient Sec13–Sec31-driven secretion

PubMed Central

Townley, Anna K.; Schmidt, Katy; Hodgson, Lorna; Stephens, David J.

2012-01-01

Epithelial morphogenesis is directed by interactions with the underlying extracellular matrix. Secretion of collagen and other matrix components requires efficient coat complex II (COPII) vesicle formation at the endoplasmic reticulum. Here, we show that suppression of the outer layer COPII component, Sec13, in zebrafish embryos results in a disorganized gut epithelium. In human intestinal epithelial cells (Caco-2), Sec13 depletion causes defective epithelial polarity and organization on permeable supports. Defects are seen in the ability of cells to adhere to the substrate, form a monolayer and form intercellular junctions. When embedded in a three-dimensional matrix, Sec13-depleted Caco-2 cells form cysts but, unlike controls, are defective in lumen expansion. Incorporation of primary fibroblasts within the three-dimensional culture substantially restores normal morphogenesis. We conclude that efficient COPII-dependent secretion, notably assembly of Sec13–Sec31, is required to drive epithelial morphogenesis in both two- and three-dimensional cultures in vitro, as well as in vivo. Our results provide insight into the role of COPII in epithelial morphogenesis and have implications for the interpretation of epithelial polarity and organization assays in cell culture. PMID:22331354

Dynamics of vascular branching morphogenesis: The effect of blood and tissue flow

NASA Astrophysics Data System (ADS)

Nguyen, Thi-Hanh; Eichmann, Anne; Le Noble, Ferdinand; Fleury, Vincent

2006-06-01

Vascularization of embryonic organs or tumors starts from a primitive lattice of capillaries. Upon perfusion, this lattice is remodeled into branched arteries and veins. Adaptation to mechanical forces is implied to play a major role in arterial patterning. However, numerical simulations of vessel adaptation to haemodynamics has so far failed to predict any realistic vascular pattern. We present in this article a theoretical modeling of vascular development in the yolk sac based on three features of vascular morphogenesis: the disconnection of side branches from main branches, the reconnection of dangling sprouts (“dead ends”), and the plastic extension of interstitial tissue, which we have observed in vascular morphogenesis. We show that the effect of Poiseuille flow in the vessels can be modeled by aggregation of random walkers. Solid tissue expansion can be modeled by a Poiseuille (parabolic) deformation, hence by deformation under hits of random walkers. Incorporation of these features, which are of a mechanical nature, leads to realistic modeling of vessels, with important biological consequences. The model also predicts the outcome of simple mechanical actions, such as clamping of vessels or deformation of tissue by the presence of obstacles. This study offers an explanation for flow-driven control of vascular branching morphogenesis.

Differentiated roles for MreB-actin isologues and autolytic enzymes in Bacillus subtilis morphogenesis.

PubMed

Domínguez-Cuevas, Patricia; Porcelli, Ida; Daniel, Richard A; Errington, Jeff

2013-09-01

Cell morphogenesis in most bacteria is governed by spatiotemporal growth regulation of the peptidoglycan cell wall layer. Much is known about peptidoglycan synthesis but regulation of its turnover by hydrolytic enzymes is much less well understood. Bacillus subtilis has a multitude of such enzymes. Two of the best characterized are CwlO and LytE: cells lacking both enzymes have a lethal block in cell elongation. Here we show that activity of CwlO is regulated by an ABC transporter, FtsEX, which is required for cell elongation, unlike cell division as in Escherichia coli. Actin-like MreB proteins are thought to play a key role in orchestrating cell wall morphogenesis. B. subtilis has three MreB isologues with partially differentiated functions. We now show that the three MreB isologues have differential roles in regulation of the CwlO and LytE systems and that autolysins control different aspects of cell morphogenesis. The results add major autolytic activities to the growing list of functions controlled by MreB isologues in bacteria and provide new insights into the different specialized functions of essential cell wall autolysins. © 2013 The Authors. Molecular Microbiology published by John Wiley & Sons Ltd.

Multiple Phosphatidylinositol 3-Kinases Regulate Vaccinia Virus Morphogenesis

PubMed Central

McNulty, Shannon; Bornmann, William; Schriewer, Jill; Werner, Chas; Smith, Scott K.; Olson, Victoria A.; Damon, Inger K.; Buller, R. Mark; Heuser, John; Kalman, Daniel

2010-01-01

Poxvirus morphogenesis is a complex process that involves the successive wrapping of the virus in host cell membranes. We screened by plaque assay a focused library of kinase inhibitors for those that caused a reduction in viral growth and identified several compounds that selectively inhibit phosphatidylinositol 3-kinase (PI3K). Previous studies demonstrated that PI3Ks mediate poxviral entry. Using growth curves and electron microscopy in conjunction with inhibitors, we show that that PI3Ks additionally regulate morphogenesis at two distinct steps: immature to mature virion (IMV) transition, and IMV envelopment to form intracellular enveloped virions (IEV). Cells derived from animals lacking the p85 regulatory subunit of Type I PI3Ks (p85α−/−β−/−) presented phenotypes similar to those observed with PI3K inhibitors. In addition, VV appear to redundantly use PI3Ks, as PI3K inhibitors further reduce plaque size and number in p85α−/−β−/− cells. Together, these data provide evidence for a novel regulatory mechanism for virion morphogenesis involving phosphatidylinositol dynamics and may represent a new therapeutic target to contain poxviruses. PMID:20526370

Embryo mechanics: balancing force production with elastic resistance during morphogenesis.

PubMed

Davidson, Lance A

2011-01-01

Morphogenesis requires the spatial and temporal control of embryo mechanics, including force production and mechanical resistance to those forces, to coordinate tissue deformation and large-scale movements. Thus, biomechanical processes play a key role in directly shaping the embryo. Additional roles for embryo mechanics during development may include the patterning of positional information and to provide feedback to ensure the success of morphogenetic movements in shaping the larval body and organs. To understand the multiple roles of mechanics during development requires familiarity with engineering principles of the mechanics of structures, the viscoelastic properties of biomaterials, and the integration of force and stress within embryonic structures as morphogenesis progresses. In this chapter, we review the basic engineering principles of biomechanics as they relate to morphogenesis, introduce methods for quantifying embryo mechanics and the limitations of these methods, and outline a formalism for investigating the role of embryo mechanics in birth defects. We encourage the nascent field of embryo mechanics to adopt standard engineering terms and test methods so that studies of diverse organisms can be compared and universal biomechanical principles can be revealed. Copyright © 2011 Elsevier Inc. All rights reserved.

The ciliopathy gene Rpgrip1l is essential for hair follicle development.

PubMed

Chen, Jiang; Laclef, Christine; Moncayo, Alejandra; Snedecor, Elizabeth R; Yang, Ning; Li, Li; Takemaru, Ken-Ichi; Paus, Ralf; Schneider-Maunoury, Sylvie; Clark, Richard A

2015-03-01

The primary cilium is essential for skin morphogenesis through regulating the Notch, Wnt, and hedgehog signaling pathways. Prior studies on the functions of primary cilia in the skin were based on the investigations of genes that are essential for cilium formation. However, none of these ciliogenic genes has been linked to ciliopathy, a group of disorders caused by abnormal formation or function of cilia. To determine whether there is a genetic and molecular link between ciliopathies and skin morphogenesis, we investigated the role of RPGRIP1L, a gene mutated in Joubert (JBTS) and Meckel (MKS) syndromes, two severe forms of ciliopathy, in the context of skin development. We found that RPGRIP1L is essential for hair follicle morphogenesis. Specifically, disrupting the Rpgrip1l gene in mice resulted in reduced proliferation and differentiation of follicular keratinocytes, leading to hair follicle developmental defects. These defects were associated with significantly decreased primary cilium formation and attenuated hedgehog signaling. In contrast, we found that hair follicle induction and polarization and the development of interfollicular epidermis were unaffected. This study indicates that RPGRIP1L, a ciliopathy gene, is essential for hair follicle morphogenesis likely through regulating primary cilia formation and the hedgehog signaling pathway.

Morphogenesis of the C. elegans vulva

PubMed Central

Schindler, Adam J

2012-01-01

Understanding how cells move, change shape, and alter cellular behaviors to form organs, a process termed morphogenesis, is one of the great challenges of developmental biology. Formation of the C. elegans vulva is a powerful, simple, and experimentally accessible model for elucidating how morphogenetic processes produce an organ. In the first step of vulval development, three epithelial precursor cells divide and differentiate to generate 22 cells of seven different vulval subtypes. The 22 vulval cells then rearrange from a linear array into a tube, with each of the seven cell types undergoing characteristic morphogenetic behaviours that construct the vulva. Vulval morphogenesis entails many of the same cellular activities that underlie organogenesis and tissue formation across species, including invagination, lumen formation, oriented cell divisions, cell-cell adhesion, cell migration, cell fusion, extracellular matrix remodelling and cell invasion. Studies of vulval development have led to pioneering discoveries in a number of these processes and are beginning to bridge the gap between the pathways that specify cells and their connections to morphogenetic behaviors. The simplicity of the vulva and the experimental tools available in C. elegans will continue to make vulval morphogenesis a powerful paradigm to further our understanding of the largely mysterious mechanisms that build tissues and organs. PMID:23418408

Multi-scale mechanics from molecules to morphogenesis

PubMed Central

Davidson, Lance; von Dassow, Michelangelo; Zhou, Jian

2009-01-01

Dynamic mechanical processes shape the embryo and organs during development. Little is understood about the basic physics of these processes, what forces are generated, or how tissues resist or guide those forces during morphogenesis. This review offers an outline of some of the basic principles of biomechanics, provides working examples of biomechanical analyses of developing embryos, and reviews the role of structural proteins in establishing and maintaining the mechanical properties of embryonic tissues. Drawing on examples we highlight the importance of investigating mechanics at multiple scales from milliseconds to hours and from individual molecules to whole embryos. Lastly, we pose a series of questions that will need to be addressed if we are to understand the larger integration of molecular and physical mechanical processes during morphogenesis and organogenesis. PMID:19394436

Embryonic lung morphogenesis in organ culture: experimental evidence for a proteoglycan function in the extracellular matrix

NASA Technical Reports Server (NTRS)

Spooner, B. S.; Bassett, K. E.; Spooner, B. S. Jr

1993-01-01

The lung rudiment, isolated from mid-gestation (11 day) mouse embryos, can undergo morphogenesis in organ culture. Observation of living rudiments, in culture, reveals both growth and ongoing bronchiolar branching activity. To detect proteoglycan (PG) biosynthesis, and deposition in the extracellular matrix, rudiments were metabolically labeled with radioactive sulfate, then fixed, embedded, sectioned and processed for autoradiography. The sulfated glycosaminoglycan (GAG) types, composing the carbohydrate component of the proteoglycans, were evaluated by selective GAG degradative approaches that showed chondroitin sulfate PG principally associated with the interstitial matrix, and heparan sulfate PG principally associated with the basement membrane. Experiments using the proteoglycan biosynthesis disrupter, beta-xyloside, suggest that when chondroitin sulfate PG deposition into the ECM is perturbed, branching morphogenesis is compromised.

Insights into the Sigma-1 receptor chaperone’s cellular functions: a microarray report

PubMed Central

Tsai, Shang-Yi; Rothman, Richard Kyle; Su, Tsung-Ping

2013-01-01

We previously demonstrated that Sig-1Rs are critical regulators in neuronal morphogenesis and development via the regulation of oxidative stress and mitochondrial functions. In the present study, we sought to identify pathways and genes that are affected by Sig-1R. Gene expression profiles were examined in rat hippocampal neurons that had been cultured for18 days in vitro (DIV). The cells were transduced with AAV siRNA targeting Sig-1R on DIV 10 for 7 days, followed by gene expression analysis using a rat genome cDNA array. The gene array results indicated that Sig-1R knockdown hampered cellular functions including steroid biogenesis, protein ubiquitination, actin cytoskeleton network, and Nrf-2 mediated oxidative stress. Many of the cellular components important for actin polymerization and synapse plasticity, including F-actin capping protein and neurofilaments, were significantly changed in AAV-siSig-1R neurons. Further, cytochrome c was reduced in AAV-Sig-1R neurons whereas free-radical generating enzymes including cytochrome p450 and cytochrome b-245 were increased. The microarray results also suggest that Sig-1Rs may regulate genes that are involved in the pathogenesis of many CNS diseases including Alzheimer’s disease and Parkinson’s disease. These data further confirmed that Sig-1Rs play critical roles in the CNS and thus these findings may aid in future development of therapeutic treatments targeting neurodegenerative disorders. PMID:21905129

The Effect of Gestational Age on Angiogenic Gene Expression in the Rat Placenta

PubMed Central

Vaswani, Kanchan; Hum, Melissa Wen-Ching; Chan, Hsiu-Wen; Ryan, Jennifer; Wood-Bradley, Ryan J.; Nitert, Marloes Dekker; Mitchell, Murray D.; Armitage, James A.; Rice, Gregory E.

2013-01-01

The placenta plays a central role in determining the outcome of pregnancy. It undergoes changes during gestation as the fetus develops and as demands for energy substrate transfer and gas exchange increase. The molecular mechanisms that coordinate these changes have yet to be fully elucidated. The study performed a large scale screen of the transcriptome of the rat placenta throughout mid-late gestation (E14.25–E20) with emphasis on characterizing gestational age associated changes in the expression of genes invoved in angiogenic pathways. Sprague Dawley dams were sacrificed at E14.25, E15.25, E17.25 and E20 (n = 6 per group) and RNA was isolated from one placenta per dam. Changes in placental gene expression were identifed using Illumina Rat Ref-12 Expression BeadChip Microarrays. Differentially expressed genes (>2-fold change, <1% false discovery rate, FDR) were functionally categorised by gene ontology pathway analysis. A subset of differentially expressed genes identified by microarrays were confirmed using Real-Time qPCR. The expression of thirty one genes involved in the angiogenic pathway was shown to change over time, using microarray analysis (22 genes displayed increased and 9 gene decreased expression). Five genes (4 up regulated: Cd36, Mmp14, Rhob and Angpt4 and 1 down regulated: Foxm1) involved in angiogenesis and blood vessel morphogenesis were subjected to further validation. qPCR confirmed late gestational increased expression of Cd36, Mmp14, Rhob and Angpt4 and a decrease in expression of Foxm1 before labour onset (P<0.0001). The observed acute, pre-labour changes in the expression of the 31 genes during gestation warrant further investigation to elucidate their role in pregnancy. PMID:24391823

The axonal guidance cue semaphorin 3C contributes to alveolar growth and repair.

PubMed

Vadivel, Arul; Alphonse, Rajesh S; Collins, Jennifer J P; van Haaften, Tim; O'Reilly, Megan; Eaton, Farah; Thébaud, Bernard

2013-01-01

Lung diseases characterized by alveolar damage such as bronchopulmonary dysplasia (BPD) in premature infants and emphysema lack efficient treatments. Understanding the mechanisms contributing to normal and impaired alveolar growth and repair may identify new therapeutic targets for these lung diseases. Axonal guidance cues are molecules that guide the outgrowth of axons. Amongst these axonal guidance cues, members of the Semaphorin family, in particular Semaphorin 3C (Sema3C), contribute to early lung branching morphogenesis. The role of Sema3C during alveolar growth and repair is unknown. We hypothesized that Sema3C promotes alveolar development and repair. In vivo Sema3C knock down using intranasal siRNA during the postnatal stage of alveolar development in rats caused significant air space enlargement reminiscent of BPD. Sema3C knock down was associated with increased TLR3 expression and lung inflammatory cells influx. In a model of O2-induced arrested alveolar growth in newborn rats mimicking BPD, air space enlargement was associated with decreased lung Sema3C mRNA expression. In vitro, Sema3C treatment preserved alveolar epithelial cell viability in hyperoxia and accelerated alveolar epithelial cell wound healing. Sema3C preserved lung microvascular endothelial cell vascular network formation in vitro under hyperoxic conditions. In vivo, Sema3C treatment of hyperoxic rats decreased lung neutrophil influx and preserved alveolar and lung vascular growth. Sema3C also preserved lung plexinA2 and Sema3C expression, alveolar epithelial cell proliferation and decreased lung apoptosis. In conclusion, the axonal guidance cue Sema3C promotes normal alveolar growth and may be worthwhile further investigating as a potential therapeutic target for lung repair.

Positioning the actual interference fringe pattern on the tooth flank in measuring gear tooth flanks by laser interferometry

NASA Astrophysics Data System (ADS)

Fang, Suping; Wang, Leijie; Liu, Shiqiao; Komori, Masaharu; Kubo, Aizoh

2011-05-01

In measuring form deviation of gear tooth flanks by laser interferometry, the collected interference fringe pattern (IFP) is badly distorted, in the case of shape, relative to the actual tooth flank. Meanwhile, a clear and definite mapping relationship between the collected IFP and the actual tooth flank is indispensable for both transforming phase differences into deviation values and positioning the measurement result on the actual tooth flank. In order to solve these problems, this paper proposes a method using the simulation tooth image as a bridge connecting the actual tooth flank and the collected IFP. The mapping relationship between the simulation tooth image and the actual tooth flank has been obtained by ray tracing methods [Fang et al., Appl. Opt. 49(33), 6409-6415 (2010)]. This paper mainly discusses how to build the relationship between the simulation tooth image and the collected IFP by using a matching algorithm of two characteristic point sets. With the combination of the two above-mentioned assistant mapping relationships, the mapping relationship between the collected IFP and the actual tooth flank can be built; the collected IFP can be positioned on the actual tooth flank. Finally, the proposed method is employed in a measurement of the form deviation of a gear tooth flank and the result proves the feasibility of the proposed method.

Cloning of rat amelotin and localization of the protein to the basal lamina of maturation stage ameloblasts and junctional epithelium.

PubMed

Moffatt, Pierre; Smith, Charles E; St-Arnaud, René; Simmons, Darrin; Wright, J Timothy; Nanci, Antonio

2006-10-01

Formation of tooth enamel is a very complex process in which a specific set of proteins secreted by ameloblasts play a primordial role. As part of a screening procedure to identify novel proteins secreted by EO (enamel organ) cells of rat incisors, we isolated a partial cDNA fragment (EO-017) that is the homologue of the recently described mouse Amtn (amelotin) gene [Iwasaki, Bajenova, Somogyi-Ganss, Miller, Nguyen, Nourkeyhani, Gao, Wendel and Ganss (2005) J. Dent. Res. 84, 1127-1132]. Presented herein is the cloning of rat and pig full-length cDNAs with their deduced protein sequences. Detailed expression profiling by Northern-blot analysis and RT (reverse transcriptase)-PCR on rat and mouse tissues revealed highest expression in the mandible, more specifically in the maturation stage of the EO. Among all tissues tested, low expression was detected only in periodontal ligament, lung, thymus and gingiva. In silico analyses revealed that the Amtn gene is highly conserved in seven other mammals, but is absent from fish, birds and amphibians. The Amtn protein is enriched in proline, leucine, glutamine and threonine (52% of total) and contains a perfectly conserved protein kinase CK2 phosphorylation site. Transient transfection experiments in HEK-293 cells (human embryonic kidney cells) showed that secreted Amtn is post-translationally modified possibly through O-linked oligosaccharides on threonine residues. In concordance with its predominant expression site, immunofluorescence localization within the rat and mouse mandibles revealed Amtn localized to the basal lamina of maturation stage ameloblasts of incisors and unerupted molars. Intense Amtn protein expression was also detected in the internal basal lamina of junctional epithelium in molars. The peculiar and unique cellular localization of Amtn suggests a role in cell adhesion.

Satisfaction with appearance and the desired treatment to improve aesthetics.

PubMed

Al-Zarea, Bader K

2013-01-01

Objective. To identify participants' satisfaction with appearance and the desired treatment to improve aesthetics. Materials and Methods. 220 participants (127 males and 93 females, mean age = 21.4 ± 1.5 years) were recruited into the study. A structured questionnaire was used to assess patients' satisfaction with appearance and what treatment they desire to improve aesthetics. Participants scored the level of satisfaction with appearance using visual analogue scale. Results. The VAS mean score of satisfaction with general appearance was 6.8 ± 2.3. Half participants were dissatisfied with tooth appearance and 65.9% were dissatisfied with tooth colour. Higher VAS scores were associated with higher desire for all treatments that improve tooth appearance (P < .05). Dissatisfaction with tooth appearance increased with increased dissatisfaction with teeth colour, feeling of poor tooth alignment, presence of fractured anterior teeth, and increased desire for orthodontic, crowns, and dentures treatments (P < .05). Dissatisfaction with tooth colour was associated with increased desire for tooth whitening and tooth coloured fillings (P < .05). Conclusions. Participants had high levels of dissatisfaction with tooth appearance and tooth colour. Dissatisfaction with tooth colour contributed to the increased dissatisfaction with tooth appearance. Dissatisfaction with tooth appearance, colour, alignment, and condition was significantly related to high desire for aesthetic treatments.

Effects of Trans-Resveratrol on hyperglycemia-induced abnormal spermatogenesis, DNA damage and alterations in poly (ADP-ribose) polymerase signaling in rat testis

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

Abdelali, Ala

Diabetes induces oxidative stress, DNA damage and alters several intracellular signaling pathways in organ systems. This study investigated modulatory effects of Trans-Resveratrol on type 1 diabetes mellitus (T1DM)-induced abnormal spermatogenesis, DNA damage and alterations in poly (ADP-ribose) polymerase (PARP) signaling in rat testis. Trans-Resveratrol administration (5mg/kg/day, ip) to Streptozotocin-induced T1DM adult male Wistar rats from day 22–42 resulted in recovery of induced oxidative stress, abnormal spermatogenesis and inhibited DNA synthesis, and led to mitigation of 8-hydroxy-2'-deoxyguanosine formation in the testis and spermatozoa, and DNA double-strand breaks in the testis. Trans-Resveratrol aggravated T1DM-induced up-regulation of aminoacyl tRNA synthetase complex-interacting multifunctional proteinmore » 2 expression; however, it did not modify the up-regulated total PARP and down-regulated PARP1 expressions, but recovered the decreased SirT1 (Sirtuin 1) levels in T1DM rat testis. Trans-Resveratrol, when given alone, reduced the poly (ADP-ribosyl)ation (pADPr) process in the testis due to an increase in PAR glycohydrolase activity, but when given to T1DM rats it did not affect the pADPr levels. T1DM with or without Trans-Resveratrol did not induce nuclear translocation of apoptosis-inducing factor and the formation of 50 kb DNA breaks, suggesting to the lack of caspase-3-independent cell death called parthanatos. T1DM with or without Trans-Resveratrol did not increase necrotic cell death in the testis. Primary spermatocytes, Sertoli cells, Leydig cells and intra-testicular vessels showed the expression of PARP pathway related proteins. In conclusion, Trans-Resveratrol mitigates T1DM-induced sperm abnormality and DNA damage, but does not significantly modulate PARP signaling pathway, except the SirT1 expression, in the rat testis. - Highlights: • Resveratrol inhibits diabetes-induced abnormal sperm morphogenesis • Resveratrol recovers diabetes-induced DNA damage in testis and spermatozoa • Resveratrol does not normalize diabetes-induced increase in total PARP • Resveratrol does not modulate diabetes-induced decrease in PARP1 • Resveratrol normalizes diabetes-induced decrease in SirT1 levels in testis.« less

A numerical algorithm of tooth profile of non-circular cylindrical gear

NASA Astrophysics Data System (ADS)

Wang, Xuan

2017-08-01

Non-circular cylindrical gear (NCCG) is a common form of non-circular gear. Different from the circular gear, the tooth profile equation of NCCG cannot be obtained. So it is necessary to use a numerical algorithm to calculate the tooth profile of NCCG. For this reason, this paper presents a simple and highly efficient numerical algorithm to obtain the tooth profile of NCCG. Firstly, the mathematical model of tooth profile envelope of NCCG is established based on the principle of gear shaping, and the tooth profile envelope of NCCG is obtained. Secondly, the polar radius and polar angle of shaper cutter tooth profile are chosen as the criterions, by which the points of NCCG tooth cogging can be screened out. Finally, the boundary of tooth cogging points is extracted by a distance criterion and correspondingly the tooth profile of NCCG is obtained.

Practical whole-tooth restoration utilizing autologous bioengineered tooth germ transplantation in a postnatal canine model

PubMed Central

Ono, Mitsuaki; Oshima, Masamitsu; Ogawa, Miho; Sonoyama, Wataru; Hara, Emilio Satoshi; Oida, Yasutaka; Shinkawa, Shigehiko; Nakajima, Ryu; Mine, Atsushi; Hayano, Satoru; Fukumoto, Satoshi; Kasugai, Shohei; Yamaguchi, Akira; Tsuji, Takashi; Kuboki, Takuo

2017-01-01

Whole-organ regeneration has great potential for the replacement of dysfunctional organs through the reconstruction of a fully functional bioengineered organ using three-dimensional cell manipulation in vitro. Recently, many basic studies of whole-tooth replacement using three-dimensional cell manipulation have been conducted in a mouse model. Further evidence of the practical application to human medicine is required to demonstrate tooth restoration by reconstructing bioengineered tooth germ using a postnatal large-animal model. Herein, we demonstrate functional tooth restoration through the autologous transplantation of bioengineered tooth germ in a postnatal canine model. The bioengineered tooth, which was reconstructed using permanent tooth germ cells, erupted into the jawbone after autologous transplantation and achieved physiological function equivalent to that of a natural tooth. This study represents a substantial advancement in whole-organ replacement therapy through the transplantation of bioengineered organ germ as a practical model for future clinical regenerative medicine. PMID:28300208

SEPT9_v1 Functions in Breast Cancer Cell Division

DTIC Science & Technology

2012-01-01

the regulation and function of septin filaments, and define new mechanisms regulating important cellular functions. BODY: 1). Study the effects...ciliogenesis. However, mechanisms for retaining these proteins and lipids in the primary cilia are not clear. We directly tested the presence of a diffusion...polarity and morphogenesis;  Defined mechanisms involving the roles of septins and microtubules in vesicle trafficking and epithelial morphogenesis

Tooth-meshing-harmonic static-transmission-error amplitudes of helical gears

NASA Astrophysics Data System (ADS)

Mark, William D.

2018-01-01

The static transmission errors of meshing gear pairs arise from deviations of loaded tooth working surfaces from equispaced perfect involute surfaces. Such deviations consist of tooth-pair elastic deformations and geometric deviations (modifications) of tooth working surfaces. To a very good approximation, the static-transmission-error tooth-meshing-harmonic amplitudes of helical gears are herein expressed by superposition of Fourier transforms of the quantities: (1) the combination of tooth-pair elastic deformations and geometric tooth-pair modifications and (2) fractional mesh-stiffness fluctuations, each quantity (1) and (2) expressed as a function of involute "roll distance." Normalization of the total roll-distance single-tooth contact span to unity allows tooth-meshing-harmonic amplitudes to be computed for different shapes of the above-described quantities (1) and (2). Tooth-meshing harmonics p = 1, 2, … are shown to occur at Fourier-transform harmonic values of Qp, p = 1, 2, …, where Q is the actual (total) contact ratio, thereby verifying its importance in minimizing transmission-error tooth-meshing-harmonic amplitudes. Two individual shapes and two series of shapes of the quantities (1) and (2) are chosen to illustrate a wide variety of shapes. In most cases representative of helical gears, tooth-meshing-harmonic values p = 1, 2, … are shown to occur in Fourier-transform harmonic regions governed by discontinuities arising from tooth-pair-contact initiation and termination, thereby showing the importance of minimizing such discontinuities. Plots and analytical expressions for all such Fourier transforms are presented, thereby illustrating the effects of various types of tooth-working-surface modifications and tooth-pair stiffnesses on transmission-error generation.

Social ranking effects on tooth-brushing behaviour.

PubMed

Maltby, John; Paterson, Kevin; Day, Liz; Jones, Ceri; Kinnear, Hayley; Buchanan, Heather

2016-05-01

A tooth-brushing social rank hypothesis is tested suggesting tooth-brushing duration is influenced when individuals position their behaviour in a rank when comparing their behaviour with other individuals. Study 1 used a correlation design, Study 2 used a semi-experimental design, and Study 3 used a randomized intervention design to examine the tooth-brushing social rank hypothesis in terms of self-reported attitudes, cognitions, and behaviour towards tooth-brushing duration. Study 1 surveyed participants to examine whether the perceived health benefits of tooth-brushing duration could be predicted from the ranking of each person's tooth-brushing duration. Study 2 tested whether manipulating the rank position of the tooth-brushing duration influenced participant-perceived health benefits of tooth-brushing duration. Study 3 used a longitudinal intervention method to examine whether messages relating to the rank positions of tooth-brushing durations causally influenced the self-report tooth-brushing duration. Study 1 demonstrates that perceptions of the health benefits from tooth-brushing duration are predicted by the perceptions of how that behaviour ranks in comparison to other people's behaviour. Study 2 demonstrates that the perceptions of the health benefits of tooth-brushing duration can be manipulated experimentally by changing the ranked position of a person's tooth-brushing duration. Study 3 experimentally demonstrates the possibility of increasing the length of time for which individuals clean their teeth by focusing on how they rank among their peers in terms of tooth-brushing duration. The effectiveness of interventions using social-ranking methods relative to those that emphasize comparisons made against group averages or normative guidelines are discussed. What is already known on this subject? Individual make judgements based on social rank information. Social rank information has been shown to influence positive health behaviours such as exercise. What does this study add? The health benefits of tooth-brushing are predicted by how tooth-brushing duration ranks within a distribution. Focussing on how teeth-cleaning duration ranks among others produces longer teeth-cleaning durations. © 2015 The British Psychological Society.

A numerical simulation of tooth movement by wire bending.

PubMed

Kojima, Yukio; Fukui, Hisao

2006-10-01

In orthodontic treatment, wires are bent and attached to teeth to move them via elastic recovery. To predict how a tooth will move, the initial force system produced from the wire is calculated. However, the initial force system changes as the tooth moves and may not be used to predict the final tooth position. The purpose of this study was to develop a comprehensive mechanical, 3-dimensional, numerical model for predicting tooth movement. Tooth movements produced by wire bending were simulated numerically. The teeth moved as a result of bone remodeling, which occurs in proportion to stress in the periodontal ligament. With an off-center bend, a tooth near the bending position was subjected to a large moment and tipped more noticeably than the other teeth. Also, a tooth far from the bending position moved slightly in the mesial or the distal direction. With the center V-bend, when the second molar was added as an anchor tooth, the tipping angle and the intrusion of the canine increased, and movement of the first molar was prevented. When a wire with an inverse curve of Spee was placed in the mandibular arch, the calculated tendency of vertical tooth movements was the same as the measured result. In these tooth movements, the initial force system changed as the teeth moved. Tooth movement was influenced by the size of the root surface area. Tooth movements produced by wire bending could be estimated. It was difficult to predict final tooth positions from the initial force system.

E- and P-cadherin expression during murine hair follicle morphogenesis and cycling.

PubMed

Müller-Röver, S; Tokura, Y; Welker, P; Furukawa, F; Wakita, H; Takigawa, M; Paus, R

1999-08-01

The role of adhesion molecules in the control of hair follicle (HF) morphogenesis, regression and cycling is still rather enigmatic. Since the adhesion molecules E- and P-cadherin (Ecad and Pcad) are functionally important, e.g. during embryonic pattern formation, we have studied their expression patterns during neonatal HF morphogenesis and cycling in C57/BL6 mice by immunohistology and semi-quantitative RT-PCR. The expression of both cadherins was strikingly hair cycle-dependent and restricted to distinct anatomical HF compartments. During HF morphogenesis, hair bud keratinocytes displayed strong Ecad and Pcad immunoreactivity (IR). While neonatal epidermis showed Ecad IR in all epidermal layers, Pcad IR was restricted to the basal layer. During later stages of HF morphogenesis and during anagen IV-VI of the adolescent murine hair cycle, the outer root sheath showed strong E- and Pcad IR. Instead, the outermost portion of the hair matrix and the inner root sheath displayed isolated Ecad IR, while the innermost portion of the hair matrix exhibited isolated Pcad IR. During telogen, all epidermal and follicular keratinocytes showed strong Ecad IR. This is in contrast to Pcad, whose IR was stringently restricted to matrix and secondary hair germ keratinocytes which are in closest proximity to the dermal papilla. These findings suggest that isolated or combined E- and/or Pcad expression is involved in follicular pattern formation by segregating HF keratinocytes into functionally distinct subpopulations; most notably, isolated Pcad expression may segregate those hair matrix keratinocytes into one functional epithelial tissue unit, which is particularly susceptible to growth control by dermal papilla-derived morphogens. The next challenge is to define which secreted agents implicated in hair growth control modulate these follicular cadherin expression patterns, and to define how these basic parameters of HF topobiology are altered during common hair growth disorders.

Review of aragonite and calcite crystal morphogenesis in thermal spring systems

NASA Astrophysics Data System (ADS)

Jones, Brian

2017-06-01

Aragonite and calcite crystals are the fundamental building blocks of calcareous thermal spring deposits. The diverse array of crystal morphologies found in these deposits, which includes monocrystals, mesocrystals, skeletal crystals, dendrites, and spherulites, are commonly precipitated under far-from-equilibrium conditions. Such crystals form through both abiotic and biotic processes. Many crystals develop through non-classical crystal growth models that involve the arrangement of nanocrystals in a precisely controlled crystallographic register. Calcite crystal morphogenesis has commonly been linked to a ;driving force;, which is a conceptual measure of the distance of the growth conditions from equilibrium conditions. Essentially, this scheme indicates that increasing levels of supersaturation and various other parameters that produce a progressive change from monocrystals and mesocrystals to skeletal crystals to crystallographic and non-crystallographic dendrites, to dumbbells, to spherulites. Despite the vast amount of information available from laboratory experiments and natural spring systems, the precise factors that control the driving force are open to debate. The fact that calcite crystal morphogenesis is still poorly understood is largely a reflection of the complexity of the factors that influence aragonite and calcite precipitation. Available information indicates that variations in calcite crystal morphogenesis can be attributed to physical and chemical parameters of the parent water, the presence of impurities, the addition of organic or inorganic additives to the water, the rate of crystal growth, and/or the presence of microbes and their associated biofilms. The problems in trying to relate crystal morphogenesis to specific environmental parameters arise because it is generally impossible to disentangle the controlling factor(s) from the vast array of potential parameters that may act alone or in unison with each other.

Zic1 and Zic4 regulate zebrafish roof plate specification and hindbrain ventricle morphogenesis

PubMed Central

Elsen, Gina E.; Choi, Louis; Millen, Kathleen; Grinblat, Yevgenya; Prince, Victoria E.

2008-01-01

During development, the lumen of the neural tube develops into a system of brain cavities or ventricles, which play important roles in normal CNS function. We have established that the formation of the hindbrain (4th) ventricle in zebrafish is dependent upon the pleiotropic functions of the genes implicated in human Dandy Walker Malformation, Zic1 and Zic4. Using morpholino knockdown we show that zebrafish Zic1 and Zic4 are required for normal morphogenesis of the 4th ventricle. In Zic1 and/or Zic4 morphants the ventricle does not open properly, but remains completely or partially fused from the level of rhombomere (r) 2 towards the posterior. In the absence of Zic function early hindbrain regionalization and neural crest development remain unaffected, but dorsal hindbrain progenitor cell proliferation is significantly reduced. Importantly, we find that Zic1 and Zic4 are required for development of the dorsal roof plate. In Zic morphants expression of roof plate markers, including lmx1b.1 and lmx1b.2, is disrupted. We further demonstrate that zebrafish Lmx1b function is required for both hindbrain roof plate development and 4th ventricle morphogenesis, confirming that roof plate formation is a critical component of ventricle development. Finally, we show that dorsal rhombomere boundary signaling centers depend on Zic1 and Zic4 function and on roof plate signals, and provide evidence that these boundary signals are also required for ventricle morphogenesis. In summary, we conclude that Zic1 and Zic4 control zebrafish 4th ventricle morphogenesis by regulating multiple mechanisms including cell proliferation and fate specification in the dorsal hindbrain. PMID:18191121

Binding of Glutathione to Enterovirus Capsids Is Essential for Virion Morphogenesis

PubMed Central

Thibaut, Hendrik Jan; Thys, Bert; Canela, María-Dolores; Aguado, Leire; Wimmer, Eckard; Paul, Aniko; Pérez-Pérez, María-Jesús; van Kuppeveld, Frank J. M.; Neyts, Johan

2014-01-01

Enteroviruses (family of the Picornaviridae) cover a large group of medically important human pathogens for which no antiviral treatment is approved. Although these viruses have been extensively studied, some aspects of the viral life cycle, in particular morphogenesis, are yet poorly understood. We report the discovery of TP219 as a novel inhibitor of the replication of several enteroviruses, including coxsackievirus and poliovirus. We show that TP219 binds directly glutathione (GSH), thereby rapidly depleting intracellular GSH levels and that this interferes with virus morphogenesis without affecting viral RNA replication. The inhibitory effect on assembly was shown not to depend on an altered reducing environment. Using TP219, we show that GSH is an essential stabilizing cofactor during the transition of protomeric particles into pentameric particles. Sequential passaging of coxsackievirus B3 in the presence of low GSH-levels selected for GSH-independent mutants that harbored a surface-exposed methionine in VP1 at the interface between two protomers. In line with this observation, enteroviruses that already contained this surface-exposed methionine, such as EV71, did not rely on GSH for virus morphogenesis. Biochemical and microscopical analysis provided strong evidence for a direct interaction between GSH and wildtype VP1 and a role for this interaction in localizing assembly intermediates to replication sites. Consistently, the interaction between GSH and mutant VP1 was abolished resulting in a relocalization of the assembly intermediates to replication sites independent from GSH. This study thus reveals GSH as a novel stabilizing host factor essential for the production of infectious enterovirus progeny and provides new insights into the poorly understood process of morphogenesis. PMID:24722756

Application of a nuclear microprobe to the study of calcified tissues

NASA Astrophysics Data System (ADS)

Coote, Graeme E.; Vickridge, Ian C.

1988-03-01

The mineral fraction of calcified tissue is largely calcium hydroxyapatite (bones and teeth) or calcium carbonate (shells and fish otoliths). Apatite has such a strong affinity for fluoride ions that the F/Ca ratio can vary markedly with position in a bone or tooth, depending on the amount of fluoride present at the time of calcification or partial recrystallization. New biological information can be obtained by introducing extra fluoride into the diet of an animal and using a microprobe later to scan sections of bones or teeth. In suitable burial sites extra fluoride is introduced after death, and the new distribution may have applications in forensic science and archaeology. Fish otoliths are also of interest since a new carbonate layer is formed each day and the distribution of trace elements may record some aspects of the fish's life history. Results from the following studies are presented: fluorine distributions in the teeth of sheep which ingested extra fluoride for known periods; distributions of calcium and fluorine in femurs of rats which drank water high in fluoride for periods from 2 to 15 weeks; calcium and fluorine distributions in artificially-prepared lesions in tooth enamel; diffusion profiles in archaeological human teeth and animal bones; patterns in the strontium/calcium ratio in sectioned otoliths of several species of fish.

Histological evaluation of the pulp in teeth from dogs with naturally occurring periodontal disease.

PubMed

Nemec, Ana; Pavlica, Zlatko; Stiblar-Martincic, Draga; Petelin, Milan; Erzen, Damjan; Crossley, David

2007-12-01

The purpose of this investigation was to evaluate the pulp of dog teeth affected by advanced periodontal disease. Histological examination was done on demineralized teeth extracted during clinical treatment of mature, client owned small and medium-size breed dogs with either good periodontal health or with advanced naturally occurring periodontal disease. Routinely stained sections from 5 clinically normal teeth and 22 teeth with advanced periodontitis from dogs between 5 and 12-years of age were examined using light microscopy. The pulp cavities of most teeth were narrow with low cellularity and some fibrosis of the pulp. Findings specific to periodontally affected teeth included acute and chronic pulpitis, vascular congestion, and pulp necrosis. A glomus body was identified in the pulp of one tooth and areas of poorly mineralized cementum were seen in both normal and diseased teeth. Age related changes in dog teeth appear similar to those reported for man and the rat. In addition to age related changes, the pulp of dog teeth with advanced periodontal disease were frequently inflamed or necrotic. This may reflect the advanced periodontitis affecting these teeth or a mechanical effect related to excessive tooth mobility. Further study is required to determine the etiology and significance of these findings and to investigate pulp status in less severely diseased teeth.

Development and growth of compound tooth plates in Callorhinchus milii (chondrichthyes, holocephali).

PubMed

Didier, D A; Stahl, B J; Zangerl, R

1994-10-01

The chimaeroid holocephalian fishes are distinguished among extant chondrichthyans by the possession of three pairs of tooth plates, evergrowing and partially hypermineralized, that are not shed and replaced like the teeth of living elasmobranchs. Although derivation of the chimaeroid tooth plate from the fusion of members of a plesiomorphic chondrichthyan tooth family has been proposed, evidence for this hypothesis has been lacking. A new analysis of the development and structure of the tooth plates in Callorhinchus milii (Holocephali, Chimaeriformes) reveals the compound nature of the tooth plates in a chimaeroid fish. Each tooth plate consists of an oral and aboral territory that form independently in the embryo and maintain separate growth surfaces through life. The descending lamina on the aboral surface of the tooth plate demarcates the growth surface of the aboral territory. Comparison with the tooth plates of Chimaera monstrosa indicates that compound tooth plates may be a feature of all chimaeroids in which a descending lamina is present. The tooth plates in these fishes represent the fusion of two members of a reduced tooth family. The condition of the tooth plates in C. milii is plesiomorphic for chimaeroids and is of evolutionary significance in that it provides further evidence to support a lyodont dentition in chimaeroid fishes similar to that found in other chondrichthyans. © 1994 Wiley-Liss, Inc. Copyright © 1994 Wiley-Liss, Inc.

An integrated miRNA functional screening and target validation method for organ morphogenesis.

PubMed

Rebustini, Ivan T; Vlahos, Maryann; Packer, Trevor; Kukuruzinska, Maria A; Maas, Richard L

2016-03-16

The relative ease of identifying microRNAs and their increasing recognition as important regulators of organogenesis motivate the development of methods to efficiently assess microRNA function during organ morphogenesis. In this context, embryonic organ explants provide a reliable and reproducible system that recapitulates some of the important early morphogenetic processes during organ development. Here we present a method to target microRNA function in explanted mouse embryonic organs. Our method combines the use of peptide-based nanoparticles to transfect specific microRNA inhibitors or activators into embryonic organ explants, with a microRNA pulldown assay that allows direct identification of microRNA targets. This method provides effective assessment of microRNA function during organ morphogenesis, allows prioritization of multiple microRNAs in parallel for subsequent genetic approaches, and can be applied to a variety of embryonic organs.

JunB is required for endothelial cell morphogenesis by regulating core-binding factor β

PubMed Central

Licht, Alexander H.; Pein, Oliver T.; Florin, Lore; Hartenstein, Bettina; Reuter, Hendrik; Arnold, Bernd; Lichter, Peter; Angel, Peter; Schorpp-Kistner, Marina

2006-01-01

The molecular mechanism triggering the organization of endothelial cells (ECs) in multicellular tubules is mechanistically still poorly understood. We demonstrate that cell-autonomous endothelial functions of the AP-1 subunit JunB are required for proper endothelial morphogenesis both in vivo in mouse embryos with endothelial-specific ablation of JunB and in in vitro angiogenesis models. By cDNA microarray analysis, we identified core-binding factor β (CBFβ), which together with the Runx proteins forms the heterodimeric core-binding transcription complex CBF, as a novel JunB target gene. In line with our findings, expression of the CBF target MMP-13 was impaired in JunB-deficient ECs. Reintroduction of CBFβ into JunB-deficient ECs rescued the tube formation defect and MMP-13 expression, indicating an important role for CBFβ in EC morphogenesis. PMID:17158955

Feedback, Lineages and Self-Organizing Morphogenesis

PubMed Central

Calof, Anne L.; Lowengrub, John S.; Lander, Arthur D.

2016-01-01

Feedback regulation of cell lineage progression plays an important role in tissue size homeostasis, but whether such feedback also plays an important role in tissue morphogenesis has yet to be explored. Here we use mathematical modeling to show that a particular feedback architecture in which both positive and negative diffusible signals act on stem and/or progenitor cells leads to the appearance of bistable or bi-modal growth behaviors, ultrasensitivity to external growth cues, local growth-driven budding, self-sustaining elongation, and the triggering of self-organization in the form of lamellar fingers. Such behaviors arise not through regulation of cell cycle speeds, but through the control of stem or progenitor self-renewal. Even though the spatial patterns that arise in this setting are the result of interactions between diffusible factors with antagonistic effects, morphogenesis is not the consequence of Turing-type instabilities. PMID:26989903

Measurement of cortical elasticity in Drosophila melanogaster embryos using ferrofluids

PubMed Central

Doubrovinski, Konstantin; Swan, Michael; Polyakov, Oleg; Wieschaus, Eric F.

2017-01-01

Many models of morphogenesis are forced to assume specific mechanical properties of cells, because the actual mechanical properties of living tissues are largely unknown. Here, we measure the rheology of epithelial cells in the cellularizing Drosophila embryo by injecting magnetic particles and studying their response to external actuation. We establish that, on timescales relevant to epithelial morphogenesis, the cytoplasm is predominantly viscous, whereas the cellular cortex is elastic. The timescale of elastic stress relaxation has a lower bound of 4 min, which is comparable to the time required for internalization of the ventral furrow during gastrulation. The cytoplasm was measured to be ∼103-fold as viscous as water. We show that elasticity depends on the actin cytoskeleton and conclude by discussing how these results relate to existing mechanical models of morphogenesis. PMID:28096360

Reverse engineering the mechanical and molecular pathways in stem cell morphogenesis.

PubMed

Lu, Kai; Gordon, Richard; Cao, Tong

2015-03-01

The formation of relevant biological structures poses a challenge for regenerative medicine. During embryogenesis, embryonic cells differentiate into somatic tissues and undergo morphogenesis to produce three-dimensional organs. Using stem cells, we can recapitulate this process and create biological constructs for therapeutic transplantation. However, imperfect imitation of nature sometimes results in in vitro artifacts that fail to recapitulate the function of native organs. It has been hypothesized that developing cells may self-organize into tissue-specific structures given a correct in vitro environment. This proposition is supported by the generation of neo-organoids from stem cells. We suggest that morphogenesis may be reverse engineered to uncover its interacting mechanical pathway and molecular circuitry. By harnessing the latent architecture of stem cells, novel tissue-engineering strategies may be conceptualized for generating self-organizing transplants. Copyright © 2013 John Wiley & Sons, Ltd.

MarvelD3 regulates the c-Jun N-terminal kinase pathway during eye development in Xenopus

PubMed Central

Vacca, Barbara; Sanchez-Heras, Elena; Steed, Emily; Balda, Maria S.; Ohnuma, Shin-Ichi; Sasai, Noriaki; Mayor, Roberto

2016-01-01

ABSTRACT Ocular morphogenesis requires several signalling pathways controlling the expression of transcription factors and cell-cycle regulators. However, despite a well-known mechanism, the dialogue between those signals and factors remains to be unveiled. Here, we identify a requirement for MarvelD3, a tight junction transmembrane protein, in eye morphogenesis in Xenopus. MarvelD3 depletion led to an abnormally pigmented eye or even an eye-less phenotype, which was rescued by ectopic MarvelD3 expression. Altering MarvelD3 expression led to deregulated expression of cell-cycle regulators and transcription factors required for eye development. The eye phenotype was rescued by increased c-Jun terminal Kinase activation. Thus, MarvelD3 links tight junctions and modulation of the JNK pathway to eye morphogenesis. PMID:27870636

A novel ALS-associated variant in UBQLN4 regulates motor axon morphogenesis

PubMed Central

Edens, Brittany M; Yan, Jianhua; Miller, Nimrod; Deng, Han-Xiang; Siddique, Teepu; Ma, Yongchao C

2017-01-01

The etiological underpinnings of amyotrophic lateral sclerosis (ALS) are complex and incompletely understood, although contributions to pathogenesis by regulators of proteolytic pathways have become increasingly apparent. Here, we present a novel variant in UBQLN4 that is associated with ALS and show that its expression compromises motor axon morphogenesis in mouse motor neurons and in zebrafish. We further demonstrate that the ALS-associated UBQLN4 variant impairs proteasomal function, and identify the Wnt signaling pathway effector beta-catenin as a UBQLN4 substrate. Inhibition of beta-catenin function rescues the UBQLN4 variant-induced motor axon phenotypes. These findings provide a strong link between the regulation of axonal morphogenesis and a new ALS-associated gene variant mediated by protein degradation pathways. DOI: http://dx.doi.org/10.7554/eLife.25453.001 PMID:28463112

Study of the kinematic and load sharing properties of wormgearing with non-symmetric tooth profiles

NASA Technical Reports Server (NTRS)

Sun, D. C.; Yuan, Qin

1995-01-01

The geometry of non-symmetric tooth profiles, i.e. tooth profiles with different pressure angles on the two sides of the tooth, is studied. A feasible non-symmetric tooth profile for application in helicopter transmissions is laid out as the best compromise among several conflicting factors. The non-symmetric tooth profile is then compared with the symmetric tooth profile studied previously. Based on the detailed comparisons it is concluded that the use of the non-symmetric tooth profile would severely limit the face width of the worm, consequently reduce the number of meshing teeth and cause much higher normal load on the individual gear teeth.

Immunodetection of osteoadherin in murine tooth extracellular matrices.

PubMed

Couble, Marie-Lise; Bleicher, Françoise; Farges, Jean-Christophe; Peyrol, Simone; Lucchini, Marion; Magloire, Henry; Staquet, Marie-Jeanne

2004-01-01

An antiserum was generated from synthetic peptides highly conserved between different mammalian species to immunolocalise the small leucine-rich proteoglycan osteoadherin (OSAD) in murine teeth. In 19-day-old embryos of rats and mice, a positive staining was found in incisor predentin and alveolar bone surrounding developing incisors and molars. In newborns, OSAD was detected at the tip of the first molar cusp where it accumulated in predentin concomitantly with odontoblast differentiation. In 2-day-old rats and mice, in the first molar, immunostaining revealed positive predentin, enamel matrix close to the apical pole of ameloblasts and a strong signal in dentin. At this stage, OSAD was detected in predentin in the second molar. Ultrastructural immunocytochemistry showed gold particles associated with collagen fibres in predentin and in foci at the dentin mineralisation front. Gold particles were also detected near the secretory pole of ameloblasts where enamel crystallites elongate. No staining was detected in pulp tissue and dental follicle. Restriction of OSAD expression to the extracellular matrix of bone, dentin and enamel suggests a role of this proteoglycan in the organisation of mineralised tissues.

Discoloration Potential of Endodontic Sealers: A Brief Review

PubMed Central

Tour Savadkouhi, Sohrab; Fazlyab, Mahta

2016-01-01

Tooth discoloration induced by endodontic sealers, is a common finding that impairs aesthetic outcome of endodontic treatment. The aim of the present mini literature review, was to summarize the existing data on discoloration potential of different endodontic sealers. The research covered the article published in PubMed and Google Scholar from 2000 to 2015. The searched keywords included ‘tooth discoloration AND endodontic’, ‘tooth discoloration AND sealer, ‘tooth discoloration AND zinc-oxide eugenol sealer’, ‘tooth discoloration AND Calcium Hydroxide Sealer’, ‘tooth discoloration AND Glass Ionomer Sealer’, ‘tooth discoloration AND epoxy-resin Sealer’, ‘tooth discoloration AND Silicon Based Sealer’, ‘tooth discoloration AND Bioceramic Sealer’ and ‘Spectrophotometry’. Conclusion: A total number of 44 articles were gained which reduced to 11 after excluding the repetitive items. The available evidence for discoloration potential of endodontic sealers currently available on the market is scarce. However, it can be concluded that all endodontic sealers can potentially stain the tooth structure to different degrees. PMID:27790251

Tooth colour change with Ozicure Oxygen Activator: a comparative in vitro tooth bleaching study.

PubMed

Grundlingh, A A; Grossman, E S; Witcomb, M J

2012-08-01

This in vitro study compared a new tooth bleaching product, Ozicure Oxygen Activator (O3, RSA) with Opalescence Quick (Ultradent, USA) using a randomised block design to assess tooth colour change. Colour change, stability and relapse in canine, incisor and premolar teeth was assessed following three bleach treatments and subsequent tooth colour assessment. Ninety nine teeth (canines, incisors and premolars), which were caries free, had no surface defects and were within the colour range 1M2 and 5M3 were selected. Teeth were randomly divided into the three experimental groups: Opalescence Quick, Ozicure Oxygen Activator and control. The three experimental groups received three treatments of one hour each over three consecutive days. Tooth colour was assessed using the Vitapan 3D Master Tooth Guide (VITA, Germany). A General Linear Models test for analysis of variance for a fractional design with significance set at P < 0.05 was used to test for significance. Both bleaching methods significantly lightened the teeth (P < 0.0001). Tooth colour change was mainly after the first hour of tooth bleaching. The tooth type was significant in tooth colour change (P = 0.0416). Tooth colour relapse and resistance to colour change were observed. Ozicure Oxygen Activator bleached teeth in a manner and to an extent similar to Opalescence Quick.

Inhibitory effect of interferon-γ on experimental tooth movement in mice.

PubMed

Kohara, Haruka; Kitaura, Hideki; Yoshimatsu, Masako; Fujimura, Yuji; Morita, Yukiko; Eguchi, Toshiko; Yoshida, Noriaki

2012-09-01

The aim of this study was to investigate the effects of interferon (IFN)-γ on experimental tooth movement in mice using a murine experimental tooth movement model. An Ni-Ti closed-coil spring was inserted between the upper-anterior alveolar bones and the upper-left first molars in mice. We evaluated the relationship between local Ifn-γ mRNA levels and orthodontic tooth movement. In other experiments, IFN-γ was injected adjacent to each first molar every other day during tooth movement. After 12 days, the amount of tooth movement was measured. Tartrate-resistant acid phosphatase (TRAP)-positive cells at the pressure side of each experimental tooth were counted as osteoclasts. Local Ifn-γ mRNA expression increased with orthodontic tooth movement. The number of TRAP-positive cells increased on the pressure side of the first molar. In contrast, the degree of tooth movement and the number of TRAP-positive cells on the pressure side in IFN-γ-injected mice were less than those of control mice. IFN-γ was induced in experimental tooth movement, and could inhibit mechanical force-loaded osteoclastogenesis and tooth movement. These results suggest that IFN-γ might be useful in controlling orthodontic tooth movement because of its inhibitory action on excessive osteoclastogenesis during this movement.

[Morphogenesis in formative process in vitro from Rehmannia glutinosa].

PubMed

Xue, Jian-ping; Zhang, Ai-min; Liu, Jun; Xu, Xue-feng

2004-01-01

To study the morphogenesis in formative process of tuberous root in vitro from Rehmannia glutinosa and compare the anatomical shape of tuberous root with nature term R. glutinosa. Tuberous roots of different vegetal phase were cut and dyed, then made into paraffin cuts and observed microscope. In anatomical shape, nature R. glutinosa and tuberous root were the same, which showed that no structural variation occurred in tuberous root induced process.

Three-dimensional morphogenesis of MDCK cells induced by cellular contractile forces on a viscous substrate

PubMed Central

Imai, Misako; Furusawa, Kazuya; Mizutani, Takeomi; Kawabata, Kazushige; Haga, Hisashi

2015-01-01

Substrate physical properties are essential for many physiological events such as embryonic development and 3D tissue formation. Physical properties of the extracellular matrix such as viscoelasticity and geometrical constraints are understood as factors that affect cell behaviour. In this study, we focused on the relationship between epithelial cell 3D morphogenesis and the substrate viscosity. We observed that Madin-Darby Canine Kidney (MDCK) cells formed 3D structures on a viscous substrate (Matrigel). The structures appear as a tulip hat. We then changed the substrate viscosity by genipin (GP) treatment. GP is a cross-linker of amino groups. Cells cultured on GP-treated-matrigel changed their 3D morphology in a substrate viscosity-dependent manner. Furthermore, to elucidate the spatial distribution of the cellular contractile force, localization of mono-phosphorylated and di-phosphorylated myosin regulatory light chain (P-MRLCs) was visualized by immunofluorescence. P-MRLCs localized along the periphery of epithelial sheets. Treatment with Y-27632, a Rho-kinase inhibitor, blocked the P-MRLCs localization at the edge of epithelial sheets and halted 3D morphogenesis. Our results indicate that the substrate viscosity, the substrate deformation, and the cellular contractile forces induced by P-MRLCs play crucial roles in 3D morphogenesis. PMID:26374384

Carlactone-independent seedling morphogenesis in Arabidopsis.

PubMed

Scaffidi, Adrian; Waters, Mark T; Ghisalberti, Emilio L; Dixon, Kingsley W; Flematti, Gavin R; Smith, Steven M

2013-10-01

Strigolactone hormones are derived from carotenoids via carlactone, and act through the α/β-hydrolase D14 and the F-box protein D3/MAX2 to repress plant shoot branching. While MAX2 is also necessary for normal seedling development, D14 and the known strigolactone biosynthesis genes are not, raising the question of whether endogenous, canonical strigolactones derived from carlactone have a role in seedling morphogenesis. Here, we report the chemical synthesis of the strigolactone precursor carlactone, and show that it represses Arabidopsis shoot branching and influences leaf morphogenesis via a mechanism that is dependent on the cytochrome P450 MAX1. In contrast, both physiologically active Z-carlactone and the non-physiological E isomer exhibit similar weak activity in seedlings, and predominantly signal through D14 rather than its paralogue KAI2, in a MAX2-dependent but MAX1-independent manner. KAI2 is essential for seedling morphogenesis, and hence this early-stage development employs carlactone-independent morphogens for which karrikins from wildfire smoke are specific surrogates. While the commonly employed synthetic strigolactone GR24 acts non-specifically through both D14 and KAI2, carlactone is a specific effector of strigolactone signalling that acts through MAX1 and D14. © 2013 The Authors The Plant Journal © 2013 John Wiley & Sons Ltd.

Regulation of cellulase expression, sporulation, and morphogenesis by velvet family proteins in Trichoderma reesei.

PubMed

Liu, Kuimei; Dong, Yanmei; Wang, Fangzhong; Jiang, Baojie; Wang, Mingyu; Fang, Xu

2016-01-01

Homologs of the velvet protein family are encoded by the ve1, vel2, and vel3 genes in Trichoderma reesei. To test their regulatory functions, the velvet protein-coding genes were disrupted, generating Δve1, Δvel2, and Δvel3 strains. The phenotypic features of these strains were examined to identify their functions in morphogenesis, sporulation, and cellulase expression. The three velvet-deficient strains produced more hyphal branches, indicating that velvet family proteins participate in the morphogenesis in T. reesei. Deletion of ve1 and vel3 did not affect biomass accumulation, while deletion of vel2 led to a significantly hampered growth when cellulose was used as the sole carbon source in the medium. The deletion of either ve1 or vel2 led to the sharp decrease of sporulation as well as a global downregulation of cellulase-coding genes. In contrast, although the expression of cellulase-coding genes of the ∆vel3 strain was downregulated in the dark, their expression in light condition was unaffected. Sporulation was hampered in the ∆vel3 strain. These results suggest that Ve1 and Vel2 play major roles, whereas Vel3 plays a minor role in sporulation, morphogenesis, and cellulase expression.

Distinct subsets of Eve-positive pericardial cells stabilise cardiac outflow and contribute to Hox gene-triggered heart morphogenesis in Drosophila.

PubMed

Zmojdzian, Monika; de Joussineau, Svetlana; Da Ponte, Jean Philippe; Jagla, Krzysztof

2018-01-17

The Drosophila heart, composed of discrete subsets of cardioblasts and pericardial cells, undergoes Hox-triggered anterior-posterior morphogenesis, leading to a functional subdivision into heart proper and aorta, with its most anterior part forming a funnel-shaped cardiac outflow. Cardioblasts differentiate into Tin-positive 'working myocytes' and Svp-expressing ostial cells. However, developmental fates and functions of heart-associated pericardial cells remain elusive. Here, we show that the pericardial cells that express the transcription factor Even Skipped adopt distinct fates along the anterior-posterior axis. Among them, the most anterior Antp-Ubx-AbdA - negative cells form a novel cardiac outflow component we call the outflow hanging structure, whereas the Antp-expressing cells differentiate into wing heart precursors. Interestingly, Hox gene expression in the Even Skipped-positive cells not only underlies their antero-posterior diversification, but also influences heart morphogenesis in a non-cell-autonomous way. In brief, we identify a new cardiac outflow component derived from a subset of Even Skipped-expressing cells that stabilises the anterior heart tip, and demonstrate non-cell-autonomous effects of Hox gene expression in the Even Skipped-positive cells on heart morphogenesis. © 2018. Published by The Company of Biologists Ltd.

The anatomical placode in reptile scale morphogenesis indicates shared ancestry among skin appendages in amniotes

PubMed Central

Di-Poï, Nicolas; Milinkovitch, Michel C.

2016-01-01

Most mammals, birds, and reptiles are readily recognized by their hairs, feathers, and scales, respectively. However, the lack of fossil intermediate forms between scales and hairs and substantial differences in their morphogenesis and protein composition have fueled the controversy pertaining to their potential common ancestry for decades. Central to this debate is the apparent lack of an “anatomical placode” (that is, a local epidermal thickening characteristic of feathers’ and hairs’ early morphogenesis) in reptile scale development. Hence, scenarios have been proposed for the independent development of the anatomical placode in birds and mammals and parallel co-option of similar signaling pathways for their morphogenesis. Using histological and molecular techniques on developmental series of crocodiles and snakes, as well as of unique wild-type and EDA (ectodysplasin A)–deficient scaleless mutant lizards, we show for the first time that reptiles, including crocodiles and squamates, develop all the characteristics of an anatomical placode: columnar cells with reduced proliferation rate, as well as canonical spatial expression of placode and underlying dermal molecular markers. These results reveal a new evolutionary scenario where hairs, feathers, and scales of extant species are homologous structures inherited, with modification, from their shared reptilian ancestor’s skin appendages already characterized by an anatomical placode and associated signaling molecules. PMID:28439533

Lamellipodia-based migrations of larval epithelial cells are required for normal closure of the adult epidermis of Drosophila

PubMed Central

Bischoff, Marcus

2012-01-01

Cell migrations are an important feature of animal development. They are, furthermore, essential to wound healing and tumour progression. Despite recent progress, it is still mysterious how cell migration is spatially and temporally regulated during morphogenesis and how cell migration is coordinated with other cellular behaviours to shape tissues and organs. The formation of the abdominal epithelium of Drosophila during metamorphosis provides an attractive system to study morphogenesis. Here, the diploid adult histoblasts replace the polyploid larval epithelial cells (LECs). Using in vivo 4D microscopy, I show that, besides apical constriction and apoptosis, the LECs undergo extensive coordinated migrations. The migrations follow a transition from a stationary (epithelial) to a migratory mode. The migratory behaviour is stimulated by autocrine Dpp signalling. Directed apical lamellipodia-like protrusions propel the cells. Initially, planar cell polarity determines the orientation of LEC migration. While LECs are migrating they also constrict apically, and changes in activity of the small GTPase Rho1 can favour one behaviour over the other. This study shows that the LECs play a more active role in morphogenesis than previously thought, with their migrations contributing to abdominal closure. It furthermore provides insights into how the migratory behaviour of cells is regulated during morphogenesis. PMID:22230614

Spatial mapping and quantification of developmental branching morphogenesis.

PubMed

Short, Kieran; Hodson, Mark; Smyth, Ian

2013-01-15

Branching morphogenesis is a fundamental developmental mechanism that shapes the formation of many organs. The complex three-dimensional shapes derived by this process reflect equally complex genetic interactions between branching epithelia and their surrounding mesenchyme. Despite the importance of this process to normal adult organ function, analysis of branching has been stymied by the absence of a bespoke method to quantify accurately the complex spatial datasets that describe it. As a consequence, although many developmentally important genes are proposed to influence branching morphogenesis, we have no way of objectively assessing their individual contributions to this process. We report the development of a method for accurately quantifying many aspects of branching morphogenesis and we demonstrate its application to the study of organ development. As proof of principle we have employed this approach to analyse the developing mouse lung and kidney, describing the spatial characteristics of the branching ureteric bud and pulmonary epithelia. To demonstrate further its capacity to profile unrecognised genetic contributions to organ development, we examine Tgfb2 mutant kidneys, identifying elements of both developmental delay and specific spatial dysmorphology caused by haplo-insufficiency for this gene. This technical advance provides a crucial resource that will enable rigorous characterisation of the genetic and environmental factors that regulate this essential and evolutionarily conserved developmental mechanism.

Ascidian notochord morphogenesis

PubMed Central

Jiang, Di; Smith, William C.

2010-01-01

The development of the notochord involves a complex set of cellular behaviors. While these morphogenic behaviors are common to all chordates, the ascidian provides a particularly attractive experimental model because of its relative simplicity. In particular, all notochord morphogenesis in ascidians takes place with only 40 cells, as opposed to the hundreds of cells in vertebrate models systems. Initial steps in ascidian notochord development convert a monolayer of epithelial-like cells in the pre-gastrula embryo to a cylindrical rod of single-cell diameter. Convergent extension is responsible for the intercalation of notochord cells and some degree of notochord elongation, while a second phase of elongation is observed as the notochord narrows medially and increases in volume. The mechanism by which the volume of the notochord increases differs between ascidian species. Some ascidian species produce extracellular pockets that will eventually coalesce to form a lumen running the length of the notochord, while others appear to make intercellular vacuoles. By either mechanism, the resulting notochord serves as a hydrostatic skeleton allowing for the locomotion of the swimming larva. Several basic cell behaviors, such as cell shape changes, cell rearrangement, establishment of cell polarity, and alteration of extracellular environment, are displayed in the process of notochord morphogenesis. Modern analysis of ascidian notochord morphogenesis promises to contribute to our understanding of these fundamental biological processes. PMID:17497687

Ascidian notochord morphogenesis.

PubMed

Jiang, Di; Smith, William C

2007-07-01

The development of the notochord involves a complex set of cellular behaviors. While these morphogenic behaviors are common to all chordates, the ascidian provides a particularly attractive experimental model because of its relative simplicity. In particular, all notochord morphogenesis in ascidians takes place with only 40 cells, as opposed to the hundreds of cells in vertebrate model systems. Initial steps in ascidian notochord development convert a monolayer of epithelial-like cells in the pregastrula embryo to a cylindrical rod of single-cell diameter. Convergent extension is responsible for the intercalation of notochord cells and some degree of notochord elongation, while a second phase of elongation is observed as the notochord narrows medially and increases in volume. The mechanism by which the volume of the notochord increases differs between ascidian species. Some ascidians produce extracellular pockets that will eventually coalesce to form a lumen running the length of the notochord; whereas others do not. By either mechanism, the resulting notochord serves as a hydrostatic skeleton allowing for the locomotion of the swimming larva. Several basic cell behaviors, such as cell shape changes, cell rearrangement, establishment of cell polarity, and alteration of extracellular environment, are displayed in the process of notochord morphogenesis. Modern analysis of ascidian notochord morphogenesis promises to contribute to our understanding of these fundamental biological processes. Copyright 2007 Wiley-Liss, Inc.

Morphogenesis of the caenorhabditis elegans vulva.

PubMed

Schindler, Adam J; Sherwood, David R

2013-01-01

Understanding how cells move, change shape, and alter cellular behaviors to form organs, a process termed morphogenesis, is one of the great challenges of developmental biology. Formation of the Caenorhabditis elegans vulva is a powerful, simple, and experimentally accessible model for elucidating how morphogenetic processes produce an organ. In the first step of vulval development, three epithelial precursor cells divide and differentiate to generate 22 cells of 7 different vulval subtypes. The 22 vulval cells then rearrange from a linear array into a tube, with each of the seven cell types undergoing characteristic morphogenetic behaviors that construct the vulva. Vulval morphogenesis entails many of the same cellular activities that underlie organogenesis and tissue formation across species, including invagination, lumen formation, oriented cell divisions, cell–cell adhesion, cell migration, cell fusion, extracellular matrix remodeling, and cell invasion. Studies of vulval development have led to pioneering discoveries in a number of these processes and are beginning to bridge the gap between the pathways that specify cells and their connections to morphogenetic behaviors. The simplicity of the vulva and the experimental tools available in C. elegans will continue to make vulval morphogenesis a powerful paradigm to further our understanding of the largely mysterious mechanisms that build tissues and organs. © 2012 Wiley Periodicals, Inc.

Three-dimensional morphogenesis of MDCK cells induced by cellular contractile forces on a viscous substrate.

PubMed

Imai, Misako; Furusawa, Kazuya; Mizutani, Takeomi; Kawabata, Kazushige; Haga, Hisashi

2015-09-16

Substrate physical properties are essential for many physiological events such as embryonic development and 3D tissue formation. Physical properties of the extracellular matrix such as viscoelasticity and geometrical constraints are understood as factors that affect cell behaviour. In this study, we focused on the relationship between epithelial cell 3D morphogenesis and the substrate viscosity. We observed that Madin-Darby Canine Kidney (MDCK) cells formed 3D structures on a viscous substrate (Matrigel). The structures appear as a tulip hat. We then changed the substrate viscosity by genipin (GP) treatment. GP is a cross-linker of amino groups. Cells cultured on GP-treated-matrigel changed their 3D morphology in a substrate viscosity-dependent manner. Furthermore, to elucidate the spatial distribution of the cellular contractile force, localization of mono-phosphorylated and di-phosphorylated myosin regulatory light chain (P-MRLCs) was visualized by immunofluorescence. P-MRLCs localized along the periphery of epithelial sheets. Treatment with Y-27632, a Rho-kinase inhibitor, blocked the P-MRLCs localization at the edge of epithelial sheets and halted 3D morphogenesis. Our results indicate that the substrate viscosity, the substrate deformation, and the cellular contractile forces induced by P-MRLCs play crucial roles in 3D morphogenesis.

The anatomical placode in reptile scale morphogenesis indicates shared ancestry among skin appendages in amniotes.

PubMed

Di-Poï, Nicolas; Milinkovitch, Michel C

2016-06-01

Most mammals, birds, and reptiles are readily recognized by their hairs, feathers, and scales, respectively. However, the lack of fossil intermediate forms between scales and hairs and substantial differences in their morphogenesis and protein composition have fueled the controversy pertaining to their potential common ancestry for decades. Central to this debate is the apparent lack of an "anatomical placode" (that is, a local epidermal thickening characteristic of feathers' and hairs' early morphogenesis) in reptile scale development. Hence, scenarios have been proposed for the independent development of the anatomical placode in birds and mammals and parallel co-option of similar signaling pathways for their morphogenesis. Using histological and molecular techniques on developmental series of crocodiles and snakes, as well as of unique wild-type and EDA (ectodysplasin A)-deficient scaleless mutant lizards, we show for the first time that reptiles, including crocodiles and squamates, develop all the characteristics of an anatomical placode: columnar cells with reduced proliferation rate, as well as canonical spatial expression of placode and underlying dermal molecular markers. These results reveal a new evolutionary scenario where hairs, feathers, and scales of extant species are homologous structures inherited, with modification, from their shared reptilian ancestor's skin appendages already characterized by an anatomical placode and associated signaling molecules.

Occlusal tooth wear in the general population of Germany: effects of age, sex, and location of teeth.

PubMed

Schierz, Oliver; Dommel, Sandra; Hirsch, Christian; Reissmann, Daniel R

2014-09-01

Tooth wear is an increasing problem in a society where people are living longer. The purpose of this study was to assess the effect of age, sex, and location of teeth on the severity of tooth wear and to determine the prevalence of dentin exposure in the general population of Germany. Tooth wear was measured in casts of both jaws of 836 persons with a 6-point (0-5) ordinal rating scale. Linear random-intercept regression models with the covariates of age, sex, jaw, and tooth group (with the participant as a grouping variable) were computed to determine the association of these covariates with tooth wear of a single tooth. The mean tooth wear score across all age groups, both sexes, and all teeth was 2.9 (standard deviation, 0.8), and the prevalence of teeth with exposed dentin was 23.4%. The participants' age was correlated with the mean tooth wear scores (r=0.51). The tooth wear level among women was on average 0.15 units lower than among men, and tooth wear was on average 0.59 units higher for anterior teeth than for posterior teeth. Increased tooth wear in anterior teeth may be due to the initially predominant guidance by anterior teeth, with age-related linear progress in tooth wear. Occlusal tooth wear scores and dentin exposure increase with age. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Tooth bleaching and young adults in Nigeria: knowledge, experiences and intention.

PubMed

Azodo, C C; Ogbomo, A C; Agbor, M A

2012-12-01

To assess the knowledge, experiences and intention to have tooth bleaching among young adults studying in a Nigerian University. A cross-section of part-time undergraduate students of University of Benin, Benin City, Nigeria were studied in 2010 using a self-administered questionnaire. About three-quarters 289 (72.4%) of the respondents reported awareness of at least one cause of tooth discoloration. A total of 143 (35.8%) of the respondents have heard of tooth bleaching with main sources of information being friends/relatives, dentists and the internet. One-third 132 (33.1%) of the respondents correctly identified that the aim of tooth bleaching was to make the teeth whiter. The respondents that had correct knowledge about mechanism, duration and complications of tooth bleaching were 51 (12.8%), 25 (6.3%) and 35 (8.8%) respectively. The major perceived benefits of tooth bleaching reported by the respondents were self confidence boost 152 (38.1%) and improvement of one's beauty 107 (26.8%). Out of the 68 (17.0%) respondents that have attempted tooth bleaching, 36 (52.9%) used tooth whitening toothpaste. Out of the 151 (37.8%) respondents that expressed intention of having tooth bleaching procedure, 32 (21.2%) would pursue the course, no matter the cost. In the studied population, knowledge of tooth discoloration was high, awareness and experiences of tooth bleaching were low but significant number expressed intention of having tooth bleaching. It is important that dentists increase oral health information particularly tooth bleaching information accessibility to the young adult population to improve the knowledge and prevent adverse effects.

Age-Related Adaptation of Bone-PDL-Tooth Complex: Rattus-Norvegicus as a Model System

PubMed Central

Leong, Narita L.; Hurng, Jonathan M.; Djomehri, Sabra I.; Gansky, Stuart A.; Ryder, Mark I.; Ho, Sunita P.

2012-01-01

Functional loads on an organ induce tissue adaptations by converting mechanical energy into chemical energy at a cell-level. The transducing capacity of cells alters physico-chemical properties of tissues, developing a positive feedback commonly recognized as the form-function relationship. In this study, organ and tissue adaptations were mapped in the bone-tooth complex by identifying and correlating biomolecular expressions to physico-chemical properties in rats from 1.5 to 15 months. However, future research using hard and soft chow over relevant age groups would decouple the function related effects from aging affects. Progressive curvature in the distal root with increased root resorption was observed using micro X-ray computed tomography. Resorption was correlated to the increased activity of multinucleated osteoclasts on the distal side of the molars until 6 months using tartrate resistant acid phosphatase (TRAP). Interestingly, mononucleated TRAP positive cells within PDL vasculature were observed in older rats. Higher levels of glycosaminoglycans were identified at PDL-bone and PDL-cementum entheses using alcian blue stain. Decreasing biochemical gradients from coronal to apical zones, specifically biomolecules that can induce osteogenic (biglycan) and fibrogenic (fibromodulin, decorin) phenotypes, and PDL-specific negative regulator of mineralization (asporin) were observed using immunohistochemistry. Heterogeneous distribution of Ca and P in alveolar bone, and relatively lower contents at the entheses, were observed using energy dispersive X-ray analysis. No correlation between age and microhardness of alveolar bone (0.7±0.1 to 0.9±0.2 GPa) and cementum (0.6±0.1 to 0.8±0.3 GPa) was observed using a microindenter. However, hardness of cementum and alveolar bone at any given age were significantly different (P<0.05). These observations should be taken into account as baseline parameters, during development (1.5 to 4 months), growth (4 to 10 months), followed by a senescent phase (10 to 15 months), from which deviations due to experimentally induced perturbations can be effectively investigated. PMID:22558292

Effects on gastric mucosa induced by dental bleaching--an experimental study with 6% hydrogen peroxide in rats.

PubMed

Paula, Anabela Baptista; Dias, Maria Isabel; Ferreira, Manuel Marques; Carrilho, Teresa; Marto, Carlos Miguel; Casalta, João; Cabrita, António Silvério; Carrilho, Eunice

2015-10-01

The value of aesthetic dentistry has precipitated several developments in the investigation of dental materials related to this field. The free marketing of these products is a problem and it is subject to various interpretations regarding its legality. There are several techniques for tooth whitening, the most used one being the external bleaching. It is the later version of such technique that poses the greatest danger of ingesting the product. The present study analysed the systemic effect of these products when they are swallowed. This experimental study aimed to observe the effects of a tooth whitening product, whose active agent is 6% hydrogen peroxide, on the gastric mucosa of healthy and non-tumour gastric pathology animals. Fifty Wistar-Han rats were used and then distributed into 5 groups, one for control and four test groups in which the bleaching product was administered in animals with and without non-tumour gastric pathology (induced by the administration of 1 sample of 50% ethanol and 5% of drinking water during 6 days) at different times of study by gavage. There was a decrease in body weight in animals of groups handled during the study period, which was most pronounced in IV and VA groups. Changes in spleen weight relative to body weight revealed no statistically significant changes. An analysis of the frequency was performed on the results of macroscopic observation of the gastric mucosa. The gastric mucosa revealed lesions in all manipulated groups, being more frequent in groups III and IV. It appears that there is a synergism when using hydrogen peroxide and 50% ethanol in the same group. Therefore, it seems that there are some signs of toxicity 3 to 4 days after administration of 6% hydrogen peroxide. The prescription of these therapies must be controlled by the clinician and the risks must be minimized.

Effects on gastric mucosa induced by dental bleaching – an experimental study with 6% hydrogen peroxide in rats

PubMed Central

PAULA, Anabela Baptista; DIAS, Maria Isabel; FERREIRA, Manuel Marques; CARRILHO, Teresa; MARTO, Carlos Miguel; CASALTA, João; CABRITA, António Silvério; CARRILHO, Eunice

2015-01-01

The value of aesthetic dentistry has precipitated several developments in the investigation of dental materials related to this field. The free marketing of these products is a problem and it is subject to various interpretations regarding its legality. There are several techniques for tooth whitening, the most used one being the external bleaching. It is the later version of such technique that poses the greatest danger of ingesting the product. The present study analysed the systemic effect of these products when they are swallowed. Objective This experimental study aimed to observe the effects of a tooth whitening product, whose active agent is 6% hydrogen peroxide, on the gastric mucosa of healthy and non-tumour gastric pathology animals. Material and Methods Fifty Wistar-Han rats were used and then distributed into 5 groups, one for control and four test groups in which the bleaching product was administered in animals with and without non-tumour gastric pathology (induced by the administration of 1 sample of 50% ethanol and 5% of drinking water during 6 days) at different times of study by gavage. There was a decrease in body weight in animals of groups handled during the study period, which was most pronounced in IV and VA groups. Changes in spleen weight relative to body weight revealed no statistically significant changes. An analysis of the frequency was performed on the results of macroscopic observation of the gastric mucosa. Results The gastric mucosa revealed lesions in all manipulated groups, being more frequent in groups III and IV. It appears that there is a synergism when using hydrogen peroxide and 50% ethanol in the same group. Conclusion Therefore, it seems that there are some signs of toxicity 3 to 4 days after administration of 6% hydrogen peroxide. The prescription of these therapies must be controlled by the clinician and the risks must be minimized. PMID:26537721

Tooth quality in dental fluorosis genetic and environmental factors.

PubMed

Vieira, A P G F; Hanocock, R; Eggertsson, H; Everett, E T; Grynpas, M D

2005-01-01

Dental fluorosis (DF) affects the appearance and structure of tooth enamel and can occur following ingestion of excess fluoride during critical periods of amelogenesis. This tooth malformation may, depending on its severity, influence enamel and dentin microhardness and dentin mineralization. Poor correlation between tooth fluoride (F) concentration and DF severity was shown in some studies, but even when a correlation was present, tooth fluoride concentration explained very little of DF severity. This fact calls into question the generally accepted hypothesis that the main factor responsible for DF severity is tooth fluoride concentration. It has been shown previously that genetic factors (susceptibility to DF) play an important role in DF severity although DF severity relates to individual susceptibility to fluoride exposure (genetics), tooth fluoride concentration relates to fluoride ingestion (environmental). The objective of this study was to investigate the correlation between tooth fluoride concentration, DF severity, and tooth mechanical and materials properties. Three strains of mice (previously shown to have different susceptibility to DF) at weaning were treated with four different levels of F in their water (0, 25, 50, and 100 ppm) for 6 weeks. Mice teeth were tested for fluoride by instrumental neutron activation analysis (INAA), DF severity determined by quantitative light-induced fluorescence [QLF], and tooth quality (enamel and dentin microhardness and dentin mineralization). Tooth fluoride concentration (environment factor) correlated positively with DF severity (QLF) (rs=0.608), fluoride treatment group (rs=0.952). However, tooth fluoride concentration correlated negatively with enamel microhardness (rs=-0.587), dentin microhardness (rs=-0.268) and dentin mineralization (rs=-0.245). Dental fluorosis (genetic factor) severity (QLF) correlated positively with fluoride treatment (rs=0.608) and tooth fluoride concentration (rs=0.583). DF severity correlated negatively with enamel microhardness (rs=-0.564) and dentin microhardness (rs=-0.356). Genetic factors (DF severity) and the environmental factor (fluoride concentration in tooth structure) have similar influence on tooth biomechanical properties, whereas only the environmental factor has an influence on tooth material property (mineralization).

Tooth - abnormal shape

MedlinePlus

Hutchinson incisors; Abnormal tooth shape; Peg teeth; Mulberry teeth; Conical teeth ... The appearance of normal teeth varies, especially the molars. ... conditions. Specific diseases can affect tooth shape, tooth ...

Evaluation of an experimental rat model for comparative studies of bleaching agents

PubMed Central

Cintra, Luciano Tavares Angelo; Benetti, Francine; Ferreira, Luciana Lousada; Rahal, Vanessa; Ervolino, Edilson; Jacinto, Rogério de Castilho; Gomes, João Eduardo; Briso, André Luiz Fraga

2016-01-01

ABSTRACT Dental materials, in general, are tested in different animal models prior to their clinical use in humans, except for bleaching agents. Objectives To evaluate an experimental rat model for comparative studies of bleaching agents by investigating the influence of different concentrations and application times of H2O2 gel in the pulp tissue during in-office bleaching of rats’ vital teeth. Material and methods The right and left maxillary molars of 50 Wistar rats were bleached with 20% and 35% H2O2 gels, respectively, for 5, 10, 15, 30, or 45 min (n=10 rats/group). Ten animals (control) were untreated. The rats were killed after 2 or 30 days, and the maxillae were examined by light microscopy. Inflammation was evaluated by histomorphometric analysis with inflammatory cell counting in the coronal and radicular thirds of the pulp. The counting of fibroblasts was also performed. Scores were attributed to the odontoblastic layer and to vascular changes. The tertiary dentin area and the pulp chamber central area were histomorphometrically measured. Data were compared by the analysis of variance and the Kruskal-Wallis test (p<0.05). Results After 2 days, the amount of inflammatory cells increased in the occlusal third of the coronal pulp until the time of 15 min for both concentrations of bleaching gels. In 30 and 45 min groups of each concentration, the number of inflammatory cells decreased along with the appearance of necrotic areas. After 30 days, a reduction in the pulp chamber central area and an enlargement of tertiary dentin area were observed without the detection of inflammation areas. Conclusion The rat model of extra coronal bleaching showed to be adequate for bleaching protocols studies, as it was possible to observe alterations in the pulp tissues and in the tooth structure caused by different concentrations and periods of application of bleaching agents. PMID:27008262

Prevalence of Tooth Shade and its Correlation with Skin Colour - A Cross-sectional Study.

PubMed

Vadavadagi, Suneel V; Kumari, K V Halini; Choudhury, Gopal Krishna; Vilekar, Abhishek Madhukar; Das, Sitansu Sekhar; Jena, Debkant; Kataraki, Bharat; B L, Bhavana

2016-02-01

Aesthetics has become an important issue in modern society. Tooth shade is one of the factors in determining aesthetics. Studies have revealed that tooth shade is influenced by age, gender, eye colour, skin colour and other factors. The present study was aimed to assess the prevalence of tooth shade and its correlation with skin colour. A total of 300 subjects aged 18-20 years were evaluated for tooth shade using Vitapan - 3D shade guide. Anterior teeth were checked under natural light and facial skin colour by Lakme liquid foundation make up as a shade guide. Data was analysed using chi square test and spearman's correlation. Out of 300 students, 114 (38.00%) had A2 tooth shade; the least prevalent tooth shade among Chitradurga population was C1 (4.00%). There was a positive correlation between tooth shade and skin colour which was found to be statistically significant (p <0.05). The most prevalent tooth shade among Chitradurga population was A2 and least was C1. There was a significant correlation between tooth shade and skin colour with lighter skin tone subjects having lighter tooth shade hence skin colour can be used as a guide for shade selection.

Application of tooth brushing behavior to active rest.

PubMed

Sadachi, Hidetoshi; Murakami, Yoshinori; Tonomura, Manabu; Yada, Yukihiro; Simoyama, Ichiro

2010-01-01

We evaluated the usefulness of tooth brushing with toothpaste as active rest using the flicker value as a physiological parameter and a subjective questionnaire as a psychological parameter. Seventeen healthy, right-handed subjects (12 males and 5 females) aged 22.5 +/- 1.5 yr (mean +/- standard deviation) were randomly divided into tooth brushing with toothpaste (N=9) and non-tooth brushing groups (N=8). The subjects performed a serial calculation task for 20 min using personal computers. Subsequently, the tooth brushing group brushed their teeth, and the flicker value and mood were compared before and after the tooth brushing. The flicker value significantly increased in the tooth brushing group compared with the non-tooth brushing group (p<0.05). Concerning the mood, in the tooth brushing group, the incidence of a "feeling of being refreshed" significantly increased (p<0.05), that of "concentration power" or a "feeling of clear-headedness" tended to increase (p<0.1), and that of "lassitude" or "sleepiness" significantly decreased (p<0.01). Somatosensory stimulation and intraoral tactile stimulation during tooth brushing activated cerebral activity, producing refreshing effects. These results suggest the applicability of tooth brushing to active rest.

[Assessment of tooth bleaching efficacy with spectrophotometer].

PubMed

Zhu, Wenhao; Liu, Chang; Pan, Jie

2014-06-01

To analyze the changes in CIE L*, a*, and b* at cervical, body, and incisal sites after tooth bleaching by using a spectrophotometer. Sixty-seven intact and healthy maxillary central incisors were in-vestigated. These incisors were darker than A3 according to the Vita Classical shade guide. The CIE tooth shade parameters L*, a*, and b* were simultaneously recorded at three tooth areas (cervical, body, and incisal) with a spectrophotometer before and after tooth bleaching (35%H2O2 coordinating with Beyond whitening accelerator irradiating). The shade dif-ferential (DeltaE) was calculated. ANOVA, paired t-test, and Pearson correlation analysis were used for data analysis. The efficacy rates of tooth bleaching were satisfactory, with 86.6%, 86.6%, and 85.1% in the cervical, body, and incisal sites, respectively. The average values of DeltaE were 5.09, 4.44, and 4.40 in the cervical, body, and incisal sites. Tooth bleaching significantly increased L* and significantly decreased a* and b* in all tooth areas (P < 0.01). The decreasing range of Deltab* was more than the increasing range of DeltaL* at the cervical site; opposite results were observed at the incisal site. A positive correlation was detected between baseline b* and DeltaE. The spectrophotometer could objectively evaluate the whitening effect of tooth bleaching at the different tooth sites. The tooth bleaching system (35%H202 coordinating with Beyond whitening accelerator irradiating) exerts powerful bleaching actions in most of the tooth areas investigated. The order of tooth bleaching effectiveness is cervicalbody>incisal. Yellow coloration is decreased mainly at the cervical site, and brightness was increased mostly at theincisal site. The effectiveness of tooth bleaching increases as the baseline b* value increases.

Distinct developmental genetic mechanisms underlie convergently evolved tooth gain in sticklebacks

PubMed Central

Ellis, Nicholas A.; Glazer, Andrew M.; Donde, Nikunj N.; Cleves, Phillip A.; Agoglia, Rachel M.; Miller, Craig T.

2015-01-01

Teeth are a classic model system of organogenesis, as repeated and reciprocal epithelial and mesenchymal interactions pattern placode formation and outgrowth. Less is known about the developmental and genetic bases of tooth formation and replacement in polyphyodonts, which are vertebrates with continual tooth replacement. Here, we leverage natural variation in the threespine stickleback fish Gasterosteus aculeatus to investigate the genetic basis of tooth development and replacement. We find that two derived freshwater stickleback populations have both convergently evolved more ventral pharyngeal teeth through heritable genetic changes. In both populations, evolved tooth gain manifests late in development. Using pulse-chase vital dye labeling to mark newly forming teeth in adult fish, we find that both high-toothed freshwater populations have accelerated tooth replacement rates relative to low-toothed ancestral marine fish. Despite the similar evolved phenotype of more teeth and an accelerated adult replacement rate, the timing of tooth number divergence and the spatial patterns of newly formed adult teeth are different in the two populations, suggesting distinct developmental mechanisms. Using genome-wide linkage mapping in marine-freshwater F2 genetic crosses, we find that the genetic basis of evolved tooth gain in the two freshwater populations is largely distinct. Together, our results support a model whereby increased tooth number and an accelerated tooth replacement rate have evolved convergently in two independently derived freshwater stickleback populations using largely distinct developmental and genetic mechanisms. PMID:26062935

Factors associated with tooth loss and prosthodontic status among Sudanese adults.

PubMed

Khalifa, Nadia; Allen, Patrick F; Abu-bakr, Neamat H; Abdel-Rahman, Manar E

2012-01-01

A study was conducted to determine the degree of tooth loss, factors influencing tooth loss, and the extent of prosthodontic rehabilitation in Sudanese adults (≥ 16 years old) attending outpatient clinics in Khartoum State. Pearson and multivariate analyses were used to examine the relationships between tooth loss and specific characteristics determined through interviews and clinical examinations. The mean number of missing teeth was 3.6 (SD, 4.9) and the prevalence of edentulism was 0.1%. The prevalence of tooth loss (missing at least one tooth) was 78%; 66.9% of tooth loss was due to caries, and 11.2% was attributable to other reasons. Prosthetic replacement of missing teeth was evident in 3%, whereas a need for prosthetic replacement was evident in 57%. Having < 20 teeth was associated with age, gender, and socioeconomic status; tooth loss due to caries was associated with age, tribe, frequency of tooth-brushing, and a low rate of dental consultation. Tooth loss due to other reasons was associated with age, tribe, education, periodontal pocketing, tobacco use, tooth wear, and prosthetic status. The results of the present study indicated that the major cause of tooth loss was dental caries, thus emphasizing the importance of a public prevention-based healthcare program. Replacement of missing teeth was uncommon in the study subjects, which may reflect lack of access to this type of oral healthcare.

Development of the oxytalan fiber system in the periodontal space of rat incisors.

PubMed

Inoue, Kouji; Hara, Yaiko; Kuroda, Noriyuki; Sato, Tetsuji

2013-10-01

The present study clarifies developmental organization of the oxytalan fiber system in the periodontal space of both the enamel (labial) and cementum (lingual) sides of rat incisors. The number of oxytalan fibers per unit area (μm(2)) was counted in rat incisors at stages of embryonic day 20 (E20) to postnatal day 35 (P35). Oxytalan fibers in the periodontal space of the enamel side were apt to decrease in number during the postnatal period, whereas their number remained almost unchanged on the cementum side during the developmental period. When the incisor emerged through the gum at P11, thinner oxytalan fibers distributed in the apical growing periodontium of the cementum side seemed to be fused with one another to become thicker fibers as has been reported for rat molars (Inoue et al., 2012). Thus, the oxytalan fiber system in the periodontal space represented significant differences in its distributional density between the enamel and cementum sides after E23. At the stage of P35, oxytalan fibers presented significantly denser distribution in all territories of the periodontal ligament of the cementum side versus the enamel side. The present findings claim that the oxytalan fiber system might bind the tooth to the periodontal ligament and provide equilibrium of vascular system and control of blood flow in the periodontal ligament of the cementum side, while it might exclusively regulate the high level of physiologically adapted vasculature in the periodontal space of the enamel side. Copyright © 2013 Elsevier GmbH. All rights reserved.

Pulpal responses to cavity preparation in aged rat molars.

PubMed

Kawagishi, Eriko; Nakakura-Ohshima, Kuniko; Nomura, Shuichi; Ohshima, Hayato

2006-10-01

The dentin-pulp complex is capable of repair after tooth injuries including dental procedures. However, few data are available concerning aged changes in pulpal reactions to such injuries. The present study aimed to clarify the capability of defense in aged pulp by investigating the responses of odontoblasts and cells positive for class II major histocompatibility complex (MHC) to cavity preparation in aged rat molars (300-360 days) and by comparing the results with those in young adult rats (100 days). In untreated control teeth, immunoreactivity for intense heat-shock protein (HSP)-25 and nestin was found in odontoblasts, whereas class-II-MHC-positive cells were densely distributed in the periphery of the pulp. Cavity preparation caused two types of pulpal reactions based on the different extent of damage in the aged rats. In the case of severe damage, destruction of the odontoblast layer was conspicuous at the affected site. By 12 h after cavity preparation, numerous class-II-MHC-positive cells appeared along the pulp-dentin border but subsequently disappeared together with HSP-25-immunopositive cells, and finally newly differentiated odontoblast-like cells took the place of the degenerated odontoblasts and acquired immunoreactivity for HSP-25 and nestin by postoperative day 3. In the case of mild damage, no remarkable changes occurred in odontoblasts after operation, and some survived through the experimental stages. These findings indicate that aged pulp tissue still possesses a defense capacity, and that a variety of reactions can occur depending on the difference in the status of dentinal tubules and/or odontoblast processes in individuals.

Influence of tooth profile on the noncircular gear tooth contact

NASA Astrophysics Data System (ADS)

Cristescu, A.; Andrei, L.; Cristescu, B.

2017-02-01

With noncircular gears, the continuous modification of the tooth meshing, in terms of variation of the tooth profiles and the line of action position and inclination, makes difficult the implementation of a general standard procedure for the analysis of the noncircular gears tooth contact. In this paper, the authors present a graphical approach that enables the tooth contact static pattern to be produced and evaluated in case of a noncircular gear with complex geometry of the pitch curve. The study is virtually developed, in AutoCAD environment, by animating and investigating the gear solid models in mesh. The tooth static contact analysis enables the path of contact area and distribution to be evaluated in correlation with the following variable initial data: gear pitch curve geometry, tooth profile geometry, as a consequence of different generating procedures, and the gear pressure angle. It was found out that the noncircular gear tooth contact could be improved by choosing different procedures for the tooth flank generation in concave and convex zones and by increasing the gear pressure angle.

The prevalence, aetiology and clinical appearance of tooth wear: the Nigerian experience.

PubMed

Oginni, O; Olusile, A O

2002-08-01

To establish the prevalence and severity of tooth wear among Nigerians and to compare the pattern and aetiology with findings of earlier studies in Western populations. Clinical examinations for tooth wear using the tooth wear index (TWI). The Federal Republic of Nigeria. Patients attending the Dental Hospital, Obafemi Awolowo University Teaching Hospital's Complex Ile-Ife. Attrition, abrasion and erosion. Of the 126 patients with tooth wear 81 had attrition, 20 had abrasion, 9 had erosion and 16 had attrition and abrasion combined. A total of 15,480 tooth surfaces were examined. 2,229 (14.4%) surfaces had tooth wear out of which 1,007 (6.5%) were pathologically worn down. The frequency of tooth wear increased with the age of patients. Most of the pathologically worn surfaces were just one point above maximum acceptable value. The aetiological factors associated with tooth wear are not different from those encountered in Western cultures but the pattern of wear differs. Pathological tooth wear presents as an age related phenomenon and is probably more severe in Nigerians.

Mechanical Control of Tissue Morphogenesis

PubMed Central

Patwari, Parth; Lee, Richard T.

2008-01-01

Mechanical forces participate in morphogenesis from the level of individual cells to whole organism patterning. This manuscript reviews recent research that has identified specific roles for mechanical forces in important developmental events. One well-defined example is that dynein-driven cilia create fluid flow that determines left-right patterning in the early mammalian embryo. Fluid flow is also important for vasculogenesis, and evidence suggests that fluid shear stress rather than fluid transport is primarily required for remodeling the early vasculature. Contraction of the actin cytoskeleton, driven by nonmuscle myosins and regulated by the Rho family GTPases, is a recurring mechanism for controlling morphogenesis throughout development, from gastrulation to cardiogenesis. Finally, novel experimental approaches suggest critical roles for the actin cytoskeleton and the mechanical environment in determining differentiation of mesenchymal stem cells. Insights into the mechanisms linking mechanical forces to cell and tissue differentiation pathways are important for understanding many congenital diseases and for developing regenerative medicine strategies. PMID:18669930

Transcriptional regulation of neuronal polarity and morphogenesis in the mammalian brain

PubMed Central

de la Torre-Ubieta, Luis; Bonni, Azad

2012-01-01

The highly specialized morphology of a neuron, typically consisting of a long axon and multiple branching dendrites, lies at the core of the principle of dynamic polarization, whereby information flows from dendrites toward the soma and to the axon. For more than a century neuroscientists have been fascinated by how shape is important for neuronal function and how neurons acquire their characteristic morphology. During the past decade, substantial progress has been made in our understanding of the molecular underpinnings of neuronal polarity and morphogenesis. In these studies, transcription factors have emerged as key players governing multiple aspects of neuronal morphogenesis from neuronal polarization and migration to axon growth and pathfinding to dendrite growth and branching to synaptogenesis. In this review, we will highlight the role of transcription factors in shaping neuronal morphology with emphasis on recent literature in mammalian systems. PMID:21982366

MicroRNAs and the Evolution of Insect Metamorphosis.

PubMed

Belles, Xavier

2017-01-31

MicroRNAs (miRNAs) are involved in the regulation of a number of processes associated with metamorphosis, either in the less modified hemimetabolan mode or in the more modified holometabolan mode. The miR-100/let-7/miR-125 cluster has been studied extensively, especially in relation to wing morphogenesis in both hemimetabolan and holometabolan species. Other miRNAs also participate in wing morphogenesis, as well as in programmed cell and tissue death, neuromaturation, neuromuscular junction formation, and neuron cell fate determination, typically during the pupal stage of holometabolan species. A special case is the control of miR-2 over Kr-h1 transcripts, which determines adult morphogenesis in the hemimetabolan metamorphosis. This is an elegant example of how a single miRNA can control an entire process by acting on a crucial mediator; however, this is a quite exceptional mechanism that was apparently lost during the transition from hemimetaboly to holometaboly.

Engineering Three-dimensional Epithelial Tissues Embedded within Extracellular Matrix.

PubMed

Piotrowski-Daspit, Alexandra S; Nelson, Celeste M

2016-07-10

The architecture of branched organs such as the lungs, kidneys, and mammary glands arises through the developmental process of branching morphogenesis, which is regulated by a variety of soluble and physical signals in the microenvironment. Described here is a method created to study the process of branching morphogenesis by forming engineered three-dimensional (3D) epithelial tissues of defined shape and size that are completely embedded within an extracellular matrix (ECM). This method enables the formation of arrays of identical tissues and enables the control of a variety of environmental factors, including tissue geometry, spacing, and ECM composition. This method can also be combined with widely used techniques such as traction force microscopy (TFM) to gain more information about the interactions between cells and their surrounding ECM. The protocol can be used to investigate a variety of cell and tissue processes beyond branching morphogenesis, including cancer invasion.

Ciona intestinalis notochord as a new model to investigate the cellular and molecular mechanisms of tubulogenesis.

PubMed

Denker, Elsa; Jiang, Di

2012-05-01

Biological tubes are a prevalent structural design across living organisms. They provide essential functions during the development and adult life of an organism. Increasing progress has been made recently in delineating the cellular and molecular mechanisms underlying tubulogenesis. This review aims to introduce ascidian notochord morphogenesis as an interesting model system to study the cell biology of tube formation, to a wider cell and developmental biology community. We present fundamental morphological and cellular events involved in notochord morphogenesis, compare and contrast them with other more established tubulogenesis model systems, and point out some unique features, including bipolarity of the notochord cells, and using cell shape changes and cell rearrangement to connect lumens. We highlight some initial findings in the molecular mechanisms of notochord morphogenesis. Based on these findings, we present intriguing problems and put forth hypotheses that can be addressed in future studies. Copyright © 2012 Elsevier Ltd. All rights reserved.

Essential role for fibrillin-2 in zebrafish notochord and vascular morphogenesis.

PubMed

Gansner, John M; Madsen, Erik C; Mecham, Robert P; Gitlin, Jonathan D

2008-10-01

Recent studies demonstrate that lysyl oxidase cuproenzymes are critical for zebrafish notochord formation, but the molecular mechanisms of copper-dependent notochord morphogenesis are incompletely understood. We, therefore, conducted a forward genetic screen for zebrafish mutants that exhibit notochord sensitivity to lysyl oxidase inhibition, yielding a mutant with defects in notochord and vascular morphogenesis, puff daddygw1 (pfdgw1). Meiotic mapping and cloning reveal that the pfdgw1 phenotype results from disruption of the gene encoding the extracellular matrix protein fibrillin-2, and the spatiotemporal expression of fibrillin-2 is consistent with the pfdgw1 phenotype. Furthermore, each aspect of the pfdgw1 phenotype is recapitulated by morpholino knockdown of fibrillin-2. Taken together, the data reveal a genetic interaction between fibrillin-2 and the lysyl oxidases in notochord formation and demonstrate the importance of fibrillin-2 in specific early developmental processes in zebrafish. Copyright (c) 2008 Wiley-Liss, Inc.

Expansion of presoldier cuticle contributes to head elongation during soldier differentiation in termites

NASA Astrophysics Data System (ADS)

Sugime, Yasuhiro; Ogawa, Kota; Watanabe, Dai; Shimoji, Hiroyuki; Koshikawa, Shigeyuki; Miura, Toru

2015-12-01

In termites, the soldier caste possesses morphological features suitable for colony defence, despite some exceptions. Soldiers are differentiated via two moultings through a presoldier stage with dramatic morphogenesis. While a number of morphological modifications are known to occur during the presoldier moult, growth and morphogenesis seem to continue even after the moult. The present study, using the damp-wood termite Hodotermopsis sjostedti, carried out morphological and histological investigations on the developmental processes during the presoldier stage that is artificially induced by the application of a juvenile hormone analogue. Measurements of five body parameters indicated that head length significantly increased during the 14-day period after the presoldier moult, while it did not increase subsequently to the stationary moult (pseudergate moult as control). Histological observations also showed that the cuticular development played a role in the presoldier head elongation, suggesting that the soft and flexible presoldier cuticle contributed to the soldier morphogenesis in termites.

Pak4 Is Required during Epithelial Polarity Remodeling through Regulating AJ Stability and Bazooka Retention at the ZA

PubMed Central

Walther, Rhian F.; Nunes de Almeida, Francisca; Vlassaks, Evi; Burden, Jemima J.; Pichaud, Franck

2016-01-01

Summary The ability of epithelial cells to assemble into sheets relies on their zonula adherens (ZA), a circumferential belt of adherens junction (AJ) material, which can be remodeled during development to shape organs. Here, we show that during ZA remodeling in a model neuroepithelial cell, the Cdc42 effector P21-activated kinase 4 (Pak4/Mbt) regulates AJ morphogenesis and stability through β-catenin (β-cat/Arm) phosphorylation. We find that β-catenin phosphorylation by Mbt, and associated AJ morphogenesis, is needed for the retention of the apical determinant Par3/Bazooka at the remodeling ZA. Importantly, this retention mechanism functions together with Par1-dependent lateral exclusion of Par3/Bazooka to regulate apical membrane differentiation. Our results reveal an important functional link between Pak4, AJ material morphogenesis, and polarity remodeling during organogenesis downstream of Par3. PMID:27052178

Assembly of embryonic and extraembryonic stem cells to mimic embryogenesis in vitro.

PubMed

Harrison, Sarah Ellys; Sozen, Berna; Christodoulou, Neophytos; Kyprianou, Christos; Zernicka-Goetz, Magdalena

2017-04-14

Mammalian embryogenesis requires intricate interactions between embryonic and extraembryonic tissues to orchestrate and coordinate morphogenesis with changes in developmental potential. Here, we combined mouse embryonic stem cells (ESCs) and extraembryonic trophoblast stem cells (TSCs) in a three-dimensional scaffold to generate structures whose morphogenesis is markedly similar to that of natural embryos. By using genetically modified stem cells and specific inhibitors, we show that embryogenesis of ESC- and TSC-derived embryos-ETS-embryos-depends on cross-talk involving Nodal signaling. When ETS-embryos develop, they spontaneously initiate expression of mesoderm and primordial germ cell markers asymmetrically on the embryonic and extraembryonic border, in response to Wnt and BMP signaling. Our study demonstrates the ability of distinct stem cell types to self-assemble in vitro to generate embryos whose morphogenesis, architecture, and constituent cell types resemble those of natural embryos. Copyright © 2017, American Association for the Advancement of Science.