BALB/c小鼠重复药物流产模型的建立及后续妊娠结局的研究

【作者】 吕芳；

【导师】 王介东；

【作者基本信息】 北京协和医学院 ， 细胞生物学， 2012， 博士

【摘要】 目的：全球每年人工流产人数众多,并且重复流产比率高。重复流产是否对后续妊娠有影响,目前没有明确结论,亟待建立动物模型对妊娠预后进行研究。本实验目的为建立BALB/c小鼠重复药物流产模型,研究小鼠经历了重复流产之后的妊娠结局。方法：BALB/c小鼠经历2次RU486药物流产之后,观察后续妊娠结局(产仔量,小鼠出生体重等)；检测妊娠中期吸收胎数量,着床点数量以及雌孕激素水平变化。同时取材E13.5胎盘组织,使用Real-time PCR和免疫组化的方法检测与胎盘功能相关基因的表达状况。并且进一步研究经历了重复流产之后的后代F1雄鼠和F1雌鼠生长发育和生殖能力的变化。结果：经历了重复药物流产的BALB/c小鼠的后续妊娠过程中,自然流产的比率显著升高。E13.5时,实验组妊娠中期E13.5吸收胎比率显著升高,着床点数目和雌孕激素水平与对照组比较无统计学差异.Real-time PCR和免疫组化结果显示,有重复流产经历的小鼠妊娠E13.5的胎盘组织中GR,11β-HSD1/2,SGK1,TF,CD31和VEGF等表达水平降低,表明重复流产小鼠在后续正常妊娠过程中胎盘功能障碍或者胎盘功能不全。重复流产小鼠的F1代肝脏组织中与代谢有关的基因PPARA,PPARG,GR及11β-HSD1的mRNA表达量显著降低。重复流产组F1雄鼠睾丸重量,精子活动能力,精子体外存活时间,交配能力,以及F1雌鼠见栓后妊娠率均显著低于对照组。结论：本实验成功建立了BALB/c小鼠重复药物流产模型,研究发现有重复流产经历的小鼠在后续妊娠过程中出现高比率自然流产现象。重复流产经历会影响后续妊娠的胎盘功能,F1雄鼠和F1雌鼠的生殖能力。我们认为有重复流产经历的小鼠在后续妊娠过程中出现自然流产,其影响可能涉及后代的生长发育以及成年后与代谢相关的疾病,值得我们进一步研究探索。综上所述,BALB/c小鼠重复流产模型为研究与人类妊娠相关的疾病提供了有益的研究平台,并且有利于研究妇女及其后代子女的健康。更多还原

【Abstract】 Aim:Medical or surgical abortion is one of the oldest, most commonly practiced, and most controversial induced procedure performed in the world. Repeated abortions account for a large portion of early pregnancy termination. But knowledge is lacking on risks of recurrent pregnancy after abortion, and other effects of abortion on subsequent pregnancy remain an important public health concern. The widely increasing trend of medical abortion and repeated abortions, particularly becoming frequent in an even younger population, critically require risk estimation. In this study, we aimed to establish a mouse model of the repeated medical termination of pregnancy and determine its subsequent outcomes.Methods:Mifepriston (RU486) medical abortion in BALB/c mice model was established to investigate the impact of medical abortion on subsequent pregnancy, including litter size and newborn birth weight. Pregnant mice were sacrificed to examine the mid-term pregnancy status and investigate the frequency of fetal resorption and placental function gene expression by real-time PCR and immunohistochemistry. Offspring liver mRNA was harvested for real-time PCR to determine the gene expression. Adult males from Fl generations of control and treatment groups were sacrificed to collect the testes and caudal epididymal sperm for further analysis, and investigated sexual function of Fl male. And we also investigated sexual function of female Fl generations.Results:Mice that previously experienced early medical abortion exhibited spontaneous abortion and pregnancy loss on subsequent pregnancy. Litter size and newborn birth weight of subsequent pregnancy were likewise adversely affected. On midgestation, spontaneous abortion occured during the subsequent pregnancy after medical abortion by RU486, but the level of progesterone and estrogen were no difference compared with control groups. We detected and analyzed metabolic gene expressions in midgestation placental and offspring liver. Medical abortion caused reduced reproductivity and affected placental dysfunction, with downregulation of tissue factor (TF), platelet endothelial cell adhesion molecule-1(CD31), vascular endothelial growth factor (VEGF), especially a panel of genes for proteins involved in metabolic functions relevant for pregnancy, such as 11β-hydroxysteroiddehydrogenase1/2(11β-HSD1/2), serine/threonine protein kinase1(SGK1) and glucocorticoid receptor (GR) expression were reduced. In the offspring, genes involved in lipid metabolism which might enhance key lipid transcription factors (PPARA and PPARG) and GR/11β-HSD1were down-regulated in the liver. We also found that F1female and male reduced their reproduction ability.Conclusion:We established an inbred model system investigating the impact of repeated first trimester mifepristone induced abortions, which led to subsequent pregnancy loss, affected placental function related gene expression, and F1generation development. This mechanism may involve epigenetic manipulation and merits further study. Thus, the model provides useful means to study the mechanism underlying the above phenomena, which will ultimately benefit the health of women and their children.更多还原