目的:探讨模拟失重对雌性大鼠生殖功能的影响及其发生机制,为太空探索者的健康保护提供可借鉴的科学线索.方法:利用尾部悬吊法建立模拟失重状态大鼠模型;选取Wistar雌性大鼠72只,随机均分为6组,3个实验组分别为:模拟失重7 d组、模拟失重14 d组和模拟失重21 d组;3个对照组是与模拟失重组相对应的自由活动组.应用酶联免疫吸附法(ELISA)检测血清中雌二醇(E2)、卵泡刺激素(FSH)和黄体生成素(LH)水平;HE染色观察卵巢组织结构,特异性脂褐素染色观察卵巢组织衰老状况;逆转录定量PCR(qRT-PCR)技术检测细胞衰老相关分子端粒酶逆转录酶(TERT)、p53、p16、p21和P27的mRNA表达水平;免疫组织化学方法检测P53、P16、P21和P27的蛋白表达;随机取健康雄性大鼠分别与各组雌性大鼠合笼,比较生育仔鼠数量和存活率.结果:与各对照组相比,模拟失重7 d组、14 d组和21 d组大鼠血清中E2下降,FSH和LH上升(P<0.05);大鼠卵巢组织卵泡数量明显减少,卵巢组织发生细胞衰老现象,细胞衰老相关分子TERT mRNA表达被抑制(P<0.05),衰老相关的细胞周期调控分子p53、p16、p21和p27在mRNA和蛋白水平表达均升高(P<0.05).各模拟失重组雌性大鼠生育的仔鼠数量较相应的对照组明显减少(P<0.05),仔鼠存活率显著下降(P<0.01).结论:尾悬吊模拟失重导致雌性大鼠生殖功能下降,该现象与模拟失重诱导卵巢组织细胞衰老和下丘脑-垂体-卵巢轴内分泌功能紊乱相关.%AIM: To investigate the effects of weightlessness simulated by tail - ventrofixation on reproductive functions in female rats and the underlying mechanism, and to provide some clues to health protection for the space explorers.METHODS: To mimic the weightless state, the rat model of tail - ventrofixation was set up.Seventy - two female Wistar rats were randomly divided into 6 groups: 7 - day, 14 - day and 21 - day tail - ventrofixation groups and the corresponding 3 control groups without tail - ventrofixation.The levels of estradiol ( E2 ), follicle stimulating hormone ( FSH ) and luteinizing hormone ( LH ) in the serum were detected by ELISA.The morphological characters of the ovary were examined under microscope with HE staining.The character of senescence was checked by senescence - specific lipofuscin staining in situ.The RNA of the ovary was extracted to detect the mRNA expression levels of telomerase reverse transeriptase ( TERT),p53, p27,p21 and P16 by qRT-PCR.The protein levels except TERT were also detected by immunohistochemistry.The male Wistar rats cohabited with the female ones to test the quantity and the survival rate of their offspring.RESULTS : Compared with the corresponding control groups, the serum level of E2 decreased in tail - ventrofixation groups ( P ＜0.05 ).However, the levels of FSH and LH increased ( P ＜0.05 ).At the same time, the number of ovarian follicle in tail - ventrofixation groups reduced compared with the corresponding control groups, and the ovary cells showed the characteristics of senescence.The expression of TERT was inhibited in tail - ventrofixation groups compared with the corresponding control groups not only in the level of mRNA but also of the proteins ( P ＜0.05 ).Meanwhile, the expression of p53 , p27 and pl6 increased ( P ＜ 0.05 ).Both the number and the survival rate of offspring rats decreased in tail - ventrofixation groups as compared with the corresponding control groups ( P ＜ 0.01 ).CONCLUSION: The state of simulated weightlessness results in decreased reproductive functions in female rats.Simulated weightlessness induces cell senescence and endocrine dysfunction of hypothalamus - pituitary - ovarian axis.
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