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本试验旨在研究胚胎期大鼠性腺生长与分化的情况。选取12.5~15.5 dpc SD大鼠胚胎为研究对象,运用PCR技术进行大鼠胚胎性别鉴定,采用H-E技术对大鼠性腺分化形态进行观察。结果表明:12.5 d的鼠胚肾管已经开始形成,生殖嵴已经建立,此时仍无明显的性别分化形态;13.5 d的鼠胚开始出现性别分化的迹象,雄性的原始性索开始形成,雌性性腺分化比雄性稍晚,此期仍不易辨别出典型的卵巢特征结构;14.5 d的鼠胚性腺形态初步成型,此期性别明显分化,雄性的原始性索开始分化为实心原始生精小管,雌性胚胎中性腺分为两层,初步形成卵巢特征;15.5 d的鼠胚,雄性胚胎性腺中已经具有明显的曲精小管的雏形,雌性胚胎卵巢特征也开始明显。大鼠胚胎性腺从13.5 d胚龄时开始分化,15.5 d胚龄性腺特征明显。  相似文献   

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Epithelial cell proliferation and apoptosis during morphogenesis of the murine palatal rugae (PR) were examined histochemically by using anti-bromodeoxyuridine (BrdU) and the terminal deoxynucleotidyl transferase-mediated UTP nick-end-labelling (TUNEL) technique. Formation of the PR rudiment was observed as an epithelial placode in fetuses at 12.5 days post-coitus (dpc). During the PR formation, BrdU-positive cells were detected mainly in the epithelium of the interplacode and interprotruding areas in fetuses administered BrdU maternally at 2 h before killing. TUNEL-positive cells were detected only at the epithelial placode area in 12.5-14.5 dpc. At 16.5-18.5 dpc, the BrdU-positive cells were decreased in number in the epithelial cells at the interprotruding area of the PR. Only a few TUNEL-positive cells were observed in the protruding area of the PR at 16.5 dpc. These results suggest that cell proliferation and apoptosis in the palatal epithelium are involved spatiotemporally in the murine PR morphogenesis.  相似文献   

5.
Bisphenol A (BPA), a candidate endocrine disruptor (ED), is considered to bind to estrogen receptors and to regulate expressions of estrogen responsive genes. It has also shown evidence of affecting the reproductive, immunological and nervous systems of mammalian embryos. However, the effects of BPA on placentae, a central organ of feto-maternal interlocution, are still unclear. To reveal the mechanisms of BPA effects on placentae in mammals, we compared the mRNA expression of 20 nuclear receptors between placentae of vehicle controls and those of orally BPA exposed pregnant mice by a DNA microarray technique. In murine placentae, mRNAs of 11 nuclear receptors were not detected. However, greater than 1.5 fold changes in mRNA expression of nine nuclear receptors between vehicle control and BPA treated mice were noted. Moreover, remarkable changes in mRNA expression of six non-nuclear receptor proteins were induced by BPA exposure. There were various differences in the effects of BPA on the expression of these mRNAs between the placentae with male embryos and those with female embryos. Such embryo-sex dependent differences are interesting and important pointers to understanding of the endocrine disrupting effect of BPA. The present data indicate that BPA affects the expression of nuclear receptor mRNAs in placentae and may disrupt the physiological functions of placentae.  相似文献   

6.
Rat uterine sensitization-associated gene-1 (USAG-1) mRNA is expressed in the uterus during the peri-implantation period, and its mRNA expression in uterine epithelial cells is highest on day 5 of pregnancy. On the other hand, since changes in USAG-1 mRNA expression in the mouse uterus are not seen during the estrous cycle, USAG-1 expression might be specifically regulated by embryonic factors rather than by the maternal environment. However, the expression pattern and function of USAG-1 in the mouse uterus have not been determined. Thus, we examined the tissue-specific USAG-1 mRNA expression in the uteri of ICR mice during peri-implantation using real-time quantitative PCR. Uterine tissues, such as the myometrium, luminal epithelium, and stroma, were collected by laser capture microdissection at 3.5-6.5 dpc. USAG-1 mRNA was expressed in the uteri of pregnant mice from 3.5 dpc to 6.5 dpc, and the highest level of expression was seen at 4.5 dpc (P<0.01). Significantly high USAG-1 mRNA expression was detected in the luminal epithelium at 4.5 dpc (P<0.05). The stroma and myometrium exhibited unchanged expression levels of USAG-1 mRNA at 3.5-5.5 dpc. USAG-1 mRNA was undetectable in blastocysts and implanting embryos. Expression of USAG-1 mRNA appears to be associated with blastocyst implantation to the luminal epithelium, suggesting that physiological or biochemical contact of the blastocyst to the uterus is required for USAG-1 expression.  相似文献   

7.
Distribution of apoptotic cells and expression of the apoptosis-related factors p53, bcl-2 and bad during morphogenesis of the murine palatine rugae (PR) were examined histochemically using the terminal deoxynucleotidyl transferase-mediated UTP nick end-labeling (TUNEL) technique and specific antibodies against apoptosis and cell cycle-related molecules. Formation of the PR rudiment was controlled by cell proliferation and apoptosis in the palatal epithelium. TUNEL-positive cells were detected only at the epithelial placode area at 12.5-13.5 days post coitus (dpc), but only a few cells were positive at the protruding PR area at 14.5-16.5 dpc. Bcl-2 protein was expressed mainly in the areas outside of those containing TUNEL-positive cells at 15.5 -6.5 dpc. P53 protein was not detected throughout gestation. Bad was detected in the epithelial layer at 13.5 and 15.5 dpc and overlapping the apoptotic area at 13.5-15.5 dpc. Apoptosis of palatal epithelial cells might therefore involve spatiotemporally regulated expression of bad during murine PR development.  相似文献   

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The mRNA expression of GPRC5B, an orphan G protein-coupled receptor, is induced by retinoic acid (RA). Because RA plays critical roles in embryonic development, reproductive functions, metabolism and homeostasis, GPRC5B is also considered crucial in these physiological events. We investigated the changes in expression of GPRC5B and RA receptor (RAR) alpha mRNAs and immunohistochemical localization of their proteins in the murine placenta and yolk sac at 13.5, 15.5 and 17.5 days post coitus. Stable levels of GPRC5B and RARalpha mRNAs were detected in the placenta and yolk sac. In the placenta, GPRC5B was present in maternal and fetal vascular endothelial cells, stromal cells, fibroblast-like cells and glycogen cells. A strong reaction to RARalpha was detected in maternal and fetal vascular endothelial cells and stromal cells. The levels of GPRC5B and RARalpha proteins in maternal and fetal vascular endothelial cells decreased with gestation. In the yolk sac, GPRC5B and RARalpha proteins were detected in vascular endothelial cells, but their levels did not change during the gestation period. These findings indicate that GPRC5B is involved in RA-dependent morphogenesis/angiogenesis and regulation of extracellular matrix synthesis in the murine placenta and yolk sac.  相似文献   

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鹌鹑早期胚胎bcl-2基因表达的差异及发育性变化   总被引：1，自引：1，他引：0  
采用RT-PCR方法,用Wpkci和β-actin引物进行多重PCR鉴定66～120 h鹌鹑胚胎样本性别后,选取不同时间点雌、雄胚胎各4枚,以β-actin为内标,测定bcl-2 mRNA的相对丰度;探讨bcl-2对鹌鹑早期胚胎发育的影响。结果表明：①雄性胚胎在66～90 h bcl-2 mRNA表达量一直维持在较低水平,96～102 h bcl-2 mRNA有所增加,但96与102 h间差异不显著（P＞0.05）,在108 h显著降低（P＜0.05）;与108 h相比,114 h显著升高,120 h维持在较高水平。雄性胚胎在66～108 h（72 h除外）bcl-2 mRNA表达均比雌性胚胎的表达量低,在114～120 h bcl-2 mRNA表达水平均比雌性胚胎的高。②雌性胚胎在66～90 h bcl-2 mRNA表达量一直维持在较低水平;与90 h相比,96 h显著升高,96～120 h逐渐降低,其中96～108 h下降,但三者间差异不显著（P＞0.05）;与108 h相比,114～120 h显著下降（P＜0.05）。③相同时间点雌、雄胚胎间的比较结果表明,84 h雌性胚胎bcl-2 mRNA表达显著高于雄性胚胎（P＜0.05）,90、108 h雌性胚胎bcl-2 mRNA表达极显著高于雄性胚胎（P＜0.01）;而在120 h雄性胚胎bcl-2 mRNA表达极显著高于雌性胚胎（P＜0.01）。鹌鹑胚胎发育早期,雌、雄样本bcl-2 mRNA表达存在一定的时序性,说明bcl-2对雌、雄鹌鹑早期分化及早期胚胎发育有重要影响。  相似文献   

10.
Retinoids show antitumor effects on human acute promyelocytic leukemia and other tumors via retinoid receptors. In dogs, the role of retinoid receptors in inhibiting tumor development remains unclear. To evaluate the correlation between the degree of expression of retinoic acid receptor alpha (RARalpha) mRNA and the antiproliferative effects of all-trans retinoic acid (ATRA) treatments, expression analysis of RARalpha mRNA and cell growth inhibition assay were performed on 17 established canine tumor cell lines, including 6 mammary gland tumor (MGT) cell lines, 3 osteosarcoma cell lines, 5 melanoma cell lines, and 3 mast cell tumor (MCT) cell lines. Among the cell lines investigated, all 3 MCT cell lines showed high expression of RARalpha, and the most effective cell growth inhibition was observed in ATRA-treated MCT cell lines. However, remarkable antiproliferative effects of ATRA treatments were not observed on other tumor cell lines with moderate or low RARalpha mRNA expression. As a result of the relationship between RARalpha mRNA expression and ATRA treatment with regression analysis, statistically significant correlation was suggested. Furthermore, real-time quantitative polymerase chain reaction analysis of RARalpha was performed on MCT tissue samples of dogs with spontaneous disease, and 5 of 9 tissues showed high expression. These results suggest that ATRA may be an effective antitumor agent for MCT in dogs, and that prior measurement of expression of RARalpha mRNA may be a good indicator of the effectiveness of ATRA treatment.  相似文献   

11.
After birth the development of appropriate detoxification mechanisms is important. Nuclear receptors (NR), such as constitutive androstane receptor (CAR), pregnane X receptor (PXR), peroxisome proliferator-activated receptor-alpha (PPARalpha), retinoid receptors (RAR, RXR), and NR target genes are involved in the detoxification of exogenous and endogenous substances. We quantified abundances of hepatic mRNA of NR and several NR target genes (cytochromes, CYP; cytochrome P450 reductase, CPR; UDP-glucuronosyl transferase, UDP) in calves at different ages. Gene expression was quantified by real-time RT-PCR. Abundance of mRNA of CAR and PXR increased from low levels at birth in pre-term calves (P0) and full-term calves (F0) to higher levels in 5-day-old calves (F5) and in 159-day-old veal calves (F159), whereas mRNA levels of PPARalpha did not exhibit significant ontogenetic changes. RARbeta mRNA levels were higher in F5 and F159 than in F0, whereas no age differences were observed for RARalpha levels. Levels of RXRalpha and RXRbeta mRNA were lower in F5 than in P0 and F0. Abundance of CYP2C8 and CYP3A4 increased from low levels in P0 and F0 to higher levels in F5 and to highest levels in F159. Abundance of CPR was transiently decreased in F0 and F5 calves. Levels of UGT1A1 mRNA increased from low levels in P0 and F0 to maximal level in F5 and F159. In conclusion, mRNA levels of NR and NR target genes exhibited ontogenetic changes that are likely of importance for handling of xeno- and endobiotics with increasing age.  相似文献   

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Gastrointestinal glutathione peroxidase (GI-GPx) is an antioxidant enzyme that has been known to be restricted to the gastrointestinal tract in rodents. In an effort to determine the expression pattern of GI-GPx mRNA during organogenesis, quantitative real-time PCR and in situ hybridization for GI-GPx mRNA were conducted in whole embryos or each developing organ of mice. GI-GPx mRNA was expressed more abundantly in the extraembryonic tissues, including placenta than in embryos on embryonic days (EDs) 7.5-18.5 (P < 0.05). When compared with the expression levels of cytosolic GPx (cGPx) mRNA, GI-GPx mRNA levels were low in the embryos, but relatively high in the extraembryonic tissues (P < 0.05). According to the results of whole mount in situ hybridizations, GI-GPx mRNA was principally expressed in the ectoplacental cone, neural tube and fold, and primitive heart at EDs 7.5-8.5. At EDs 9.5-12.5, GI-GPx mRNA was abundantly expressed in nervous tissues such as the telencephalon, mesencephalon and dorsal neural tube and was also detected in the forelimb and hindlimb at EDs 10.5-12.5. In the sectioned embryos after ED 13.5, GI-GPx mRNA levels were high in the cerebral cortex, metanephric corpuscle, pancreatic ducts, surface epithelia of the skin, inner ear, and nasal conchae, gastrointestinal tract, liver, urinary bladder, airway passages of lung, and whisker follicles. These findings indicate that GI-GPx is not only spatiotemporally expressed in a variety of embryonic organs during organogenesis but also may perform a mutual compensatory role with the cGPx in the protection of embryos and extraembryonic tissues against the reactive oxygen species generated in ontogenetic periods.  相似文献   

14.
Bisphenol A (BPA) is a xenoestrogen commonly used in food storage plastics. The present study was conducted to clarify the effects of BPA administration to pregnant mice on serum calcium (Ca) and Ca metabolism of the gut and kidney. From 6.5 to 16.5 days post coitus (dpc), pregnant mice were administered at 2 mg or 20 mg/kg body weight/day of BPA. Serum Ca was decreased in mice treated with 20 mg BPA at 17.5 dpc, but no remarkable differences were detected in the alkaline phosphatase activity and vitamin D receptor protein expression in the duodenum and jejunum. The messenger RNA (mRNA) expressions of calcium binding protein (CaBP‐9k) and active vitamin D synthesis enzyme (CYP27B1) in the kidney were increased in mice treated with 20 mg BPA. The mRNA expressions of occludin and junction adherence molecular A (JAM‐A) in the duodenum and ileum, which regulate paracellular transport, were increased in mice treated with 20 mg BPA. However, the administration of 2 mg BPA had no effect on serum Ca and mRNA expressions of relative genes in Ca metabolism. These results imply that BPA administration at 20 mg/kg body weight/day during pregnancy decreases serum Ca in pre‐delivery mice, which may be partly due to decreased paracellular Ca absorption.  相似文献   

15.
Ossification during embryogenesis of female and male mouse fetuses between 14.5 and 18.5 days post coitum (d.p.c.) was investigated with two methods. The Alizarin-red based method allows differential staining of cartilage and bone tissue on whole animal, however standard histochemical methods allow detailed identification of cells involved in ossification process. There were minor differences in the time of occurrence of some ossification centers between male and female mouse fetuses in a period of 14.5 - 18.5 d.p.c. At 14.5 d.p.c. ossification of female but not male mandible was observed and at 18.5 d.p.c. histochemistry demonstrated ossification in the phalanges in male but not in female.  相似文献   

16.
Sequential pattern of ossification and expression of oestrogen receptor alpha (ERalpha) during development of the skeleton in male and female mice fetuses was investigated. Twenty-seven mice fetuses of gestational age between 14.5 and 18.5 days post coitum (p.c.) were examined by haematoxylin-eosin and toluidine blue staining to determine the ossification. The presence of ERalpha was detected by immunostaining using ERalpha-specific antibodies. Ossification centres were determined in fetuses of 14.5 days p.c. of both sexes in the base of skull, ribs and front limbs, while in the mandible ossification was observed only in female fetuses at that age. ERalpha was found in all investigated tissues in which the occurrence of ossification centres was determined. ERalpha was first detected in some tissues involved in ossification at 14.5 days p.c. in fetuses of both genders. There were some minor gender differences in the pattern of ERalpha expression. ERalpha was localized in the metatarsal chondrogenic condensations at 14.5 days p.c. and in phalangeal chondrocytes at 17.5 and 18.5 days p.c. only in females. ERalpha-positive osteogenic cells at 14.5 days p.c. in the mandible were seen only in females. At 16.5 days p.c. male but not female fetuses expressed ERalpha in the vertebrae. Our findings support the view that ERalpha protein is found in the tissues that undergo bone formation and that ERalpha expression in these tissues shows only minor gender differences in mice fetuses.  相似文献   

17.
Cytoplasmic Cu/Zn superoxide dismutase (SOD1) is an antioxidant enzyme that converts superoxide to hydrogen peroxide in cells. Its spatial distribution matches that of superoxide production, allowing it to protect cells from oxidative stress. SOD1 deficiencies result in embryonic lethality and a wide range of pathologies in mice, but little is known about normal SOD1 protein expression in developing embryos. In this study, the expression pattern of SOD1 was investigated in post-implantation mouse embryos and extraembryonic tissues, including placenta, using Western blotting and immunohistochemical analyses. SOD1 was detected in embryos and extraembryonic tissues from embryonic day (ED) 8.5 to 18.5. The signal in embryos was observed at the lowest level on ED 9.5-11.5, and the highest level on ED 17.5-18.5, while levels remained constant in the surrounding extraembryonic tissues during all developmental stages examined. Immunohistochemical analysis of SOD1 expression on ED 13.5-18.5 revealed its ubiquitous distribution throughout developing organs. In particular, high levels of SOD1 expression were observed in the ependymal epithelium of the choroid plexus, ganglia, sensory cells of the olfactory and vestibulocochlear epithelia, blood cells and vessels, hepatocytes and hematopoietic cells of the liver, lymph nodes, osteogenic tissues, and skin. Thus, SOD1 is highly expressed at late stages of embryonic development in a cell- and tissue-specific manner, and can function as an important antioxidant enzyme during organogenesis in mouse embryos.  相似文献   

18.
为了研究孕鼠在孕期暴露双酚A（bisphenol A,BPA）对仔鼠生殖激素及相关基因的影响,试验将40只昆明孕鼠随机分为A、B、C、D共4组,每组10只。其中A组为对照组,饲喂普通鼠粮;B、C、D组孕鼠整个妊娠期（妊娠1 d至分娩）分别按每只鼠每天50、500、2 500 mg/kg体重给予BPA,待孕鼠自然分娩,观察记录仔鼠死亡情况。至仔鼠性成熟（56日龄）剖杀仔鼠,摘取睾丸或卵巢称重并计算脏器指数,HE染色观察卵巢或睾丸组织结构的变化,ELISA试剂盒分析仔鼠血清睾酮（T）、促卵泡素（FSH）及雌二醇（E2）水平,免疫组织化学方法检测仔鼠睾丸或卵巢Bax、Bcl-2蛋白的表达,实时荧光定量PCR检测仔鼠睾丸StAR、CYP11a或卵巢AMH、Kitlg mRNA表达。结果显示,孕鼠暴露BPA极显著增加了仔鼠死亡率（P<0.01）,显著降低了仔鼠睾丸重（P<0.05）。ELISA检测结果表明,孕鼠暴露BPA极显著降低了仔鼠T（♂）及FSH（♀）含量（P<0.01）,极显著升高了仔鼠（♀） E2水平（P<0.01）。HE染色结果显示,随BPA剂量增加,仔鼠睾丸组织损伤严重,间质细胞减少;卵巢组织结构随BPA剂量增大,空泡逐渐增多,黄体颗粒数量逐渐减少。免疫组化结果显示,孕鼠暴露BPA增加了仔鼠睾丸或卵巢组织中Bax阳性蛋白表达,减少了Bcl-2阳性蛋白表达,显著降低了雄性仔鼠StAR mRNA表达量（P<0.05）;B、D组雄性仔鼠CYP11a mRNA表达量极显著降低（P<0.01）,而C组CYP11a mRNA表达量极显著升高（P<0.01）;C、D组雌鼠Kitlg mRNA表达极显著降低（P<0.01）,AMH mRNA表达量显著升高（P<0.05）。本试验结果表明,孕鼠妊娠期暴露不同剂量BPA增加了仔鼠死亡率,扰乱了生殖激素平衡和睾丸/卵巢中相关凋亡蛋白及生殖基因表达。  相似文献   

19.
This study was aimed to investigate the reproductive toxicity of bisphenol A (BPA) exposed to the mother on the offsprings mice. Forty pregnant Kunming mice were randomly divided into 4 groups, i.e. groups A, B, C and D with 10 mice in each group. Group A was the control group and the mice received conventional feeds, mice in groups B, C and D were given 50,500 and 2 500 mg/kg BW BPA in feedstuffs during the whole gestation period (from 1 d to parturition), respectively. The death rates of the offsprings were calculated every week. The offspring mice were sacrificed at 56 days of age (at puberty). The morphology of ovary and testicular tissues were observed with hematoxylin-eosin (HE) staining. The levels of estradiol (E2), follicle stimulating hormone (FSH), testosterone (T) in mice serum were detected with ELISA Kit. The protein levels of Bax and Bcl-2 in ovary or testicular tissues were detected with immunohistochemistry, and the StAR,CYP11a mRNA levels in testicular tissues, the AMH, Kitlg mRNA levels in ovary were measured using Real-time PCR. The results showed that exposure of BPA to the mother extremely significantly increased the mortality (P<0.01),and significantly reduced the testicular weight of offspring mice (P<0.05). Maternal exposure to BPA extremely significantly reduced the levels of T (♂) and FSH(♀) (P<0.01),and extremely significantly elevated E2 (♀) level in offspring mice (P<0.01). BPA exposure damaged the testicular with less leydig cells and ovarian tissues with more vacuoles and less corpus granules in offspring mice. Immunohistochemistry results revealed that maternal exposure to BPA increased the Bax protein level and decreased the Bcl-2 protein level of testicular and ovary tissues in offspring mice. BPA significantly reduced the StAR mRNA expression in male offsprings (P<0.05). However, the mRNA level of CYP11a in groups B and D extremely significantly decreased while group C showed an significant elevation in male offsprings (P<0.01). The expression levels of Kitlg mRNA in groups C and D were decreased extremely significantly in female offsprings (P<0.01), the AMH mRNA expression in groups C and D increased significantly (P<0.05). The conclusion indicated that pregnant mice exposed to different doses of BPA had harmful effects on survival rate in offspring mice, and impact the reproductive hormones, proteins and genes expression.  相似文献   

20.
Whereas sexual differentiation is considered as the onset of differentiation of the male or female gonads, mounting evidence indicates that sex differences in developmental programming are established as early as the zygotic stage. Genetic and epigenetic differences between the sexes might govern how each responds to shifts in their early environment, including in the uterus or culture dish, as in the case of in vitro cultured pre-implantational embryos. Even if no differences are evident between the sexes at birth, divergent conceptus responses to surrounding changes, such as maternal diet and exposure to endocrine disrupting compounds (EDC), such as bisphenol A (BPA), might predispose one sex over the other to later adult-onset diseases, otherwise termed developmental origin of health and disease (DOHaD). Overall, males subjected to less than optimal in utero conditions tend to be at greater risk for various diseases, including neurobehavioural disorders. As the placenta is the primary nutrient acquisition and communication organ between the dam and foetus, its ability to adapt rapidly to environmental shifts might buffer the conceptus against environmental insults. The placenta of one sex over the other might possess greater ability to respond to environmental fluctuations. In utero environmental changes, including maternal nutrient excess or reduction or exposure to the EDC, BPA, might govern sex-dependent behavioural alterations. In sum, this review examines the evidence to date that male and female zygotes and conceptuses diverge in their responses to shifting environmental conditions and whether these contrasting sexually dimorphic responses underpin later DOHaD outcomes, namely neurobehavioural changes.  相似文献   

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