瘦素长受体缺失小鼠生殖功能障碍的分子机制研究

The Molecular Mechanism of db/db Mice Reproduction Disorder

目的:探讨引起瘦素长受体缺失(LR-)小鼠(db/db小鼠)生殖功能障碍的原因,阐明瘦素与生殖功能障碍的直接关系。方法:将LR-的雌性db/db小鼠和其同窝出生的有完整LR(LR+)的雌性野生型C57BL/6J小鼠进行异体卵巢原位移植,构建实验小鼠的LR基因型组合。分别为躯体LR-、卵巢LR+(KO组)和躯体LR+、卵巢LR+(WT组),每组各7只动物。移植后恢复2周然后监测卵巢的周期变化,连续2个周期。于小鼠动情间期取血检测血清性激素水平和糖脂代谢指标;用RT-PCR法检测卵巢组织STAR,CYP17,CYP19,OB-RB,JAK2,STAT3,PIAS3和SOCS3的mRNA表达水平。结果:①卵巢移植术后KO组小鼠无动情周期,WT组小鼠动情周期正常,2组间卵巢、子宫质量、雌二醇、促卵泡生成素水平、体质量、脂肪垫、葡萄糖、胰岛素、总胆固醇和低密度脂蛋白胆固醇差异均有统计学意义(P<0.01)。②KO组卵巢中甾体激素STAR,CYP17和CYP19的mRNA的表达量均低于WT组。2组卵巢中均有OB-RB mRNA表达,且KO组OB-RB,STAT3,PIAS3和SOCS3的mRNA表达强于WT组。结论:①db/db小鼠机体内分泌环境异常(高血糖高血脂内分泌环境、低促性腺激素)下调卵巢甾体激素合成酶基因的表达,引起卵巢功能减退。②卵巢作为一个较小的内分泌器官并不能影响全身的糖脂代谢。

Objective：To search the etiopathogenisis of db/db mice reproductive failure,which is supposed to be involved in the interaction of leptin and reproduction.Methods：Adult,female C57BL/6J mice were used in these studies.Littermate wide types（LR＋）,as well as diabetic（db/db）mutant genotypes（LR-）,were matched for the allograft of the ovary.Different genotypic mice were constructed with body LR-,ovary LR＋ in Group KO,as well as body LR＋,ovary LR＋ in Group WT,respectively（n=7）.The stage of cyclicity was determined by microscopic analysis of the predominant cell type in vaginal smears obtained daily,starting 2 weeks after transplantation,during two cycles.Mice in diestrus were decapitated.Blood was collected and centrifuged,and serum was stored for analysis of sex hormone and lipid profile.The ovaries were used to detect the levels of STAR,CYP 17,CYP 19,OB-RB,JAK 2,STAT 3,PIAS 3 and SOCS 3 mRNA.Results：Our results show that the mice displayed absent cycles in KO group,and the mice had normal cycles in WT group.The levels of E2,FSH,GLU,INS,CHO,LDL-C,body weight,fat weight and ovary weight as well as uterus weight were significant different in two groups.The ovarian mRNA expression of the STAR,CYP17 and CYP19 were lower in the KO group than in the WT group,but the expression of the OB-RB,STAT 3,PIAS 3,SOCS 3 mRNA were higher in the KO group than in the WT group.Conclusion：There were abnormal endocrine state in db/db mice（hyperglycaemia,hyperlipemia and lower gonadotropic hormone levels）.The abnormal state can down regulation the mRNA expression of the ovarian steroid synthetase and result the hyop-ovarianism.Ovary is not essential to whole glycometabolism and lipid metabolism.