围生期环境雌激素暴露对子代睾丸发育和生精过程的影响及其分子机制

发布时间：2018-03-26 03:25

本文选题：BPA　切入点：睾丸　出处：《南京医科大学》2012年硕士论文

【摘要】：双酚A（bisphenol A，BPA）是酚类环境雌激素的一种，结构类似于雌二醇（E2）和己烯雌酚（diethylstilbestrol，DES），主要用于生产聚碳酸酯、环氧树脂、聚砜树脂、聚苯醚树脂等多种高分子材料，也可用于生产增塑剂、阻燃剂、抗氧化剂、热稳定剂、橡胶防老化剂、农药、涂料等精细化工产品，这些物品的反复使用及暴露于高热环境会导致BPA的浸出。BPA不仅在多种环境介质和低等生物体中被广泛检出，而且在许多国家人群样本，如血液、尿液、精液、羊水、乳汁中等，也不断有被检出的报道[1]，这表明BPA能通过胎盘屏障，影响子代的发育。本研究的目的是探讨围产期低剂量BPA暴露对雄性子代生殖系统的影响及其机制。SD大鼠妊娠期第10d至产后第7d（GD10－PND7）皮下注射BPA2ug/kgbw/d，检测F1代雄性大鼠：①PND18、PND21、PND24血清卵泡刺激素（FSH）、黄体生成素（LH）、血清睾酮（T）、血清雌激素（E2）及睾丸内睾酮水平；②PND11、PND18、PND21、PND24体重和睾丸重；③睾丸组织形态学改变；④PND54（SD雄性大鼠附睾尾部第一波精子出现的时间点）附睾尾部精子数目以及形态学改变。研究结果显示：①从PND21开始，BPA组F1代雄性血清卵泡刺激素（FSH）、黄体生成素（LH）水平明显高于control组，而睾丸内睾酮水平相对于control组下降；②从PND21开始，BPA组F1代雄性体重相对于control组增加；③PND24（SD雄性大鼠睾丸生精小管精子细胞出现的时间点），，BPA组F1代雄性精子细胞阳性的生精小管数占总生精小管数的百分比、平均每个生精小管的精子细胞数目、生精小管直径明显高于control组；④PND54，BPA组F1代雄性附睾尾部第一波精子畸形率明显高于control组。因此我们推测围产期BPA的暴露可能影响了F1代雄性睾丸生精细胞减数分裂细胞周期，减数分裂异常，第一波精子畸形率增加。为了探寻BPA组F1代雄性睾丸内睾酮水平下降的机制，我们运用real-timePCR，检测了F1代雄性睾丸内睾酮合成相关限速酶基因star、p450scc、CYP17a、3-HSD、173-HSD的相对mRNA水平，和control组相比，BPA组大部分都存在下降趋势，且BPA组3-HSD相对mRNA水平在PND21明显低于control组。为了探寻BPA组F1代雄性大鼠睾丸生精细胞减数分裂细胞周期异常的机制，我们运用real-timePCR检测了F1代雄性睾丸内减数分裂细胞周期蛋白及其激酶基因和checkpoint基因相对mRNA水平。周期蛋白基因cyclinA1相对mRNA水平在PND21、PND24的BPA组明显高于control组；checkpoint基因TRIP13相对mRNA水平在PND21的BPA组明显低于control组；这些基因对于减数分裂的过程是至关重要的，因此我们推测这些基因相对mRNA水平的差异可能和睾丸形态学以及精子形态学差异有联系。我们结合形态学表型以及这些基因的表达趋势，寻找到F1代雄性睾丸内与精子发生相关的c-jun、c-fos原癌基因相对mRNA水平在BPA组和control组差异有明显差异。因此我们推测围产期SD大鼠低剂量BPA暴露，可能影响了F1代雄性大鼠睾丸生精细胞减数分裂的相关事件，从而促使精子发生紊乱，第一波精子畸形率增加，为进一步探讨EDCs导致男性不育的分子机制提供基础。
[Abstract]:Bisphenol A (bisphenol A BPA) is a kind of phenolic environmental estrogens, a structure similar to estradiol (E2) and diethylstilbestrol (diethylstilbestrol, DES), mainly for the production of polycarbonate, epoxy resin, polysulfone resin, a polyphenylene ether resin and other polymer materials, can also be used in the production of plasticizer, flame retardant antioxidant, heat stabilizer, anti ageing agent, rubber, pesticide, paint and other fine chemical products, these items for repeated use and exposure to high temperature environment will lead to the leaching of.BPA BPA not only in various environmental media and lower organisms are widely detected in many countries, and the population samples, such as blood, urine, semen, amniotic fluid. Milk medium, also have been reported to be detected [1], suggesting that BPA can pass through the placenta barrier and affect the development of the offspring.
The purpose of this study is to explore the perinatal exposure to low doses of BPA the reproductive system of male offspring and its mechanism in.SD rats during pregnancy and postpartum in 10d 7d (GD10 PND7) by subcutaneous injection of BPA2ug/kgbw/d, detection of F1 generation male rats: PND18, PND21, PND24 of serum follicle stimulating hormone, luteinizing hormone (FSH) erythropoietin (LH), serum testosterone (T), serum estradiol (E2) and intratesticular testosterone levels; the PND11, PND18, PND21, PND24 body weight and testis weight; the change of testicular tissue morphology; 4 PND54 (SD male rat epididymal sperm at the first time point) change of epididymal sperm the number and morphology.
The results showed as follows: starting from PND21, BPA group of F1 generation male serum follicle stimulating hormone (FSH), luteinizing hormone (LH) levels were significantly higher than that of control group, and the testosterone level in comparison to the control group decreased; the PND21 from the beginning, BPA group of F1 generation male weight compared with group control and PND24 (SD increase; male rat seminiferous tubule sperm cells the time), the percentage of the total number of seminiferous tubules seminiferous tubules in group BPA of F1 generation male sperm cells were positive, the average number of sperm cells in the seminiferous tubules of the seminiferous tubule diameter was significantly higher than that of control group; the PND54, BPA group of F1 generation male the first wave of epididymal sperm malformation rate was significantly higher than control group. So we speculate that BPA may affect the perinatal exposure of F1 generation male spermatogenic cell meiotic cell cycle, abnormal meiosis, the first wave of sperm deformity rate increased.
In order to explore the mechanism of testosterone in the testis of male BPA group decreased F1, we use real-timePCR, the detection of F1 generation male testicular testosterone synthesis related enzyme gene star, P450scc, CYP17a, 3-HSD, relative mRNA level of 173-HSD, compared with control group, BPA group of have downward trend, and the relative mRNA the level of BPA 3-HSD in group PND21 was significantly lower than that of control group.
In order to explore the mechanism of the BPA group of F1 generation male rats testis spermatogenic cell meiotic cell cycle abnormalities, we used real-timePCR to detect F1 generation male testis meiotic cell cycle protein and its relative level of mRNA kinase gene and checkpoint gene. The relative level of mRNA cyclin gene cyclinA1 in PND21, BPA group PND24 was significantly higher than control group mRNA; relative level of checkpoint gene in TRIP13 was significantly lower than that in control group BPA group PND21; these genes are essential for meiosis, so we speculate that these genes relative to the differences in the level of mRNA and the morphology of the testis and sperm morphological differences are linked. We combine the morphological phenotype and gene expression trend of these, to find the associated the c-Jun and F1 generation male sperm in the testis c-fos gene relative to the mRNA level in BPA group and control group There is a significant difference in the difference.
We therefore hypothesized that perinatal SD rats of low dose BPA exposure may affect the related events of F1 generation male rat spermatogenic cells meiosis, thus contributing tospermatogenesis disorder, the first wave of sperm deformity rate increased, provide the basis for the molecular mechanism of male sterility for the further study of EDCs causes.

【学位授予单位】：南京医科大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R114

【共引文献】