多囊卵巢综合征大鼠模型AR与CARM1及其产物的表达

Expression of AR and CARM1 as well as its product in rat PCOS model

目的:探讨脱氢表雄酮(dehydroepiandrosterone,DHEA)诱导的SD大鼠多囊卵巢综合征(polycystic ovarian syndrome,PCOS)模型效果,检测该模型中雄激素受体(androgen receptor,AR)与共激活因子相关的精氨酸甲基转移酶1(coactivator-associated arginine methyltransferase 1,CARM1)表达情况,研究PCOS模型中胰岛素抵抗、激素改变、AR与CARM1及其产物非对称二甲精氨酸(asymmetric dimethylarginines,ADMA)之间的关系。方法:将40只23日龄雌性SD大鼠随机分为实验组和对照组,每组20只,实验组每日皮下注射DHEA 0.6 mg/kg,对照组同时同位置注射等量注射用油。连续20 d后观察大鼠卵巢组织学形态及体质量、性激素、空腹血糖、胰岛素(insulin,Ins)及血清ADMA变化,评价胰岛素抵抗情况,并用免疫组化确定CARM1在卵巢组织中的表达情况,Western blot及荧光定量PCR检测卵巢AR、CARM1蛋白及m RNA转录表达情况。结果:PCOS实验组最终体质量、增加体质量、卵巢重量均明显高于对照组(P<0.05);血清空腹血糖、胰岛素、胰岛素抵抗指数(homeostasis model assessment index,HOMA index)、ADMA、睾酮(testosterone,T)、雌二醇(estrodiol,E2)均明显高于对照组(P<0.05);实验组卵巢出现大量闭锁卵泡、囊状卵泡,颗粒细胞层减少,卵母细胞消失等特征;卵巢组织中的CARM1主要由颗粒细胞表达;AR、CARM1蛋白量及m RNA表达量实验组明显高于对照组(P<0.05)。结论:CARM1及其产物ADMA与PCOS高雄激素血症、排卵功能障碍和胰岛素抵抗之间存在相关性,但二者与PCOS上述三大病理生理特点之间的内在联系及其具体机理仍需要进一步验证。

Objective：To explore the efficacy of dehydroepiandrosterone （DHEA） induced SD rat polycystic ovarian syndrome （P COS） model,to detect androgen receptor（AR） and coactivator-associated arginine methyhransferase 1 （CARM1）expressions, and to investi- gate the relationship between hormone change,insulin resistance, AR and CARM1, asymmetric dimethylarginines（ADMA）. Methods： The 23-day-old female SD rats were randomly divided into two groups. The rats in model group were injected with 0.6 ml/kg DHEA daily for 20 days while the rats in control group were injected with the same volum oil at the same time. Ovarian morphology changes, hormone in blood,insulin resistance,mRNA and protein expression of AR and CARM1 were dected one by one. Immunohistoehemistry identified the expression of CARM1 in ovarian tissue. Results：The average body weight of rats in model group at the end of this ex- periment was significantly higher than that in control group（P〈0.05）. The same result was achived concerning the average weight of ovaries and the weight gain of rats during the experiment（P〈0.05）.The fasting insulin and HOMA index,ADMA,testosterone, estro- diol were significantly higher in model group than those in control group（P〈0.05）, so as the mRNA and protein expression of AR and CARM1 （P〈0.05）. In ovarian tissue of rats in model group, a large number of atretic and cystic ovarian follicles emerged, granulosa cell layer decreased and oocytes disappeared. CARM1 expressed mainly by the granulosa cells in ovarian tissue. Conclusion ：There is a correlation between CARM1 and three major pathophysiological characteristics of PCOS,hyperandrogenism,ovarian dysfunction and insulin resistance, but the internal relations and specific mecha- nism still need further verification.