痰脂消汤调控PCOS-IR模型大鼠卵巢PI3K/Akt途径探讨

目的:观察痰脂消汤对来曲唑灌胃联合高脂膳食诱导的多囊卵巢综合征胰岛素抵抗(PCOS-IR)模型大鼠卵巢胰岛素信号转导途径的影响。方法:来曲唑灌胃联合高脂膳食喂养SD大鼠建立PCOS-IR模型,大鼠随机分为模型组、痰脂消汤组(35 g·kg~(-1)·d~(-1))、二甲双胍组(200 mg·kg~(-1)·d~(-1)),连续灌胃20 d;另设正常组。实验结束后,腹主动脉采血,测定血清空腹血糖(FPG)和空腹胰岛素(FINS)浓度,并计算胰岛素抵抗指数(HOMA-IR);实时荧光定量PCR(Real-time PCR)检测大鼠卵巢胰岛素受体(INSR),胰岛素受体底物(IRS)-1,酯酰肌醇-3激酶(PI3K),蛋白激酶B(Akt)mRNA表达;蛋白免疫印迹法(Western blot)检测卵巢组织INSR,IRS-1,PI3K,Akt蛋白及其相应磷酸化水平表达。结果:与空白组比较,模型组大鼠空腹胰岛素(FINS),HOMA-IR水平均显著升高(P0.01),FPG无明显升高;模型组大鼠卵巢INSR,IRS,PI3K,Akt mRNA表达水平明显降低(P0.05);INSR,p-INSR,IRS,p-IRS,PI3K,p-PI3K,Akt,p-Akt等蛋白表达水平明显降低(P0.05);INSR,IRS,PI3K及Akt磷酸化比例明显降低(P0.05)。与模型组比较,中药和二甲双胍治疗后大鼠FINS,HOMA-IR均显著降低(P0.01);大鼠卵巢INSR,IRS,PI3K,Akt mRNA表达水平均明显升高(P0.05);INSR,p-INSR,IRS,p-IRS,PI3K,p-PI3K,Akt,p-Akt等蛋白表达水平明显升高(P0.05);INSR,IRS,PI3K及Akt磷酸化比例明显升高(P0.05)。结论:PCOS大鼠存在IR,卵巢内PI3K/Akt信号途径转导存在异常。痰脂消汤能够显著改善大鼠胰岛素抵抗,可能与调控胰岛素信号转导通路中关键的蛋白表达有关。

Effect of Tanzhixiao Recipe on PI3K/Akt Pathway in PCOS-IR Model Rats

Objective: To observe the effect of Tanzhixiao recipe (TZXR) on signal transduction of ovarian insulin in rats with letrozole and high-fat diet induced insulin resistance in polycystic ovary syndrome (PCOS-IR). Method: Female SD rats were fed with letrozole by gavage and high-fat diet to induce PCOS-IR models. Then the rats were randomly divided into model group, TZXR group (35 g·kg^-1·d^-1) and the metformin group (200 mg·kg^-1·d^-1). The drugs were given by gavage administration for 20 days, and another normal blank group was established. After the end of the experiment, abdominal aortic blood was taken to determine fasting plasma glucose (FPG), and fasting insulin (FINS), and insulin resistance index was calculated by homeostasis model of assessment for insulin resistance index (HOMA-IR). The mRNA expression levels of insulin receptor (INSR), insulin receptor substrate-1 (IRS-1), phosphatidylinositol-3-kinase (PI3K), and protein kinase B (Akt) were detected by Real-time PCR. In addition, the expression levels of INSR, IRS, PI3K, Akt protein and their corresponding phosphorylated forms were detected by Western blot. Result: As compared with the blank group, the levels of FINS and HOMA-IR were increased in model group (P<0.01), but there was no significant increase in FPG level, mRNA expression levels of INSR, IRS, PI3K and Akt were significantly decreased (P<0.05), protein expression levels of INSR, p-INSR, IRS, p-IRS, PI3K, p-PI3K, Akt and p-AKT were significantly decreased (P<0.05), the phosphorylation ratios of INSR, IRS, PI3K, and Akt were significantly decreased in the model group (P<0.05). As compared with the model group, the levels of FINS and HOMA-IR were significantly decreased (P<0.01), mRNA expression levels of INSR, IRS, PI3K and Akt were significantly increased (P<0.05),protein expression levels of INSR, p-INSR, IRS, p-IRS, PI3K, p-PI3K, Akt and p-Akt were significantly increased (P<0.05), and phosphorylation ratios of INSR, IRS, PI3K, and Akt were significantly increased (P<0.05) in the TZXR group and metformin group. Conclusion: IR and abnormal signal transduction of PI3K/Akt pathway existed in PCOS model rats. TZXR could improve IR of PCOS rats, and the mechanism may be associated with regulating key protein expression levels of insulin signal trasduction pathway.