α-硫辛酸对糖尿病大鼠肾脏miR-21和Smad7表达及纤维化的影响

目的:观察α-硫辛酸(ALA)对糖尿病(DM)大鼠肾脏的保护作用,并探讨其作用机制。方法:将SD大鼠分为正常对照(NC)组、DM组和ALA组,给药6周后处死大鼠测定相应生化指标和肾脏指数。HE和Masson染色观察肾组织的形态结构变化; Western blot检测大鼠肾组织中转化生长因子β1 (TGF-β1)、p-Smad2/3、Smad7、collagen I和collagen III的蛋白表达水平; RT-qPCR检测肾组织微小RNA-21 (miR-21)的表达。结果:与NC组相比,DM组大鼠肾重/体重、血葡萄糖(BG)、血总胆固醇、血甘油三酯和24 h尿蛋白均显著增高,肾脏病理学检查显示出现肾纤维化改变,Smad7蛋白水平显著降低,TGF-β1、p-Smad2/3、collagen I和collagen III显著增高,miR-21水平亦显著升高(P 0. 05); ALA治疗后,DM大鼠除了BG无明显变化外,其余生化指标和肾脏指数均明显低于DM组,肾脏病理学检查显示肾纤维化病变明显得到改善,Smad7蛋白较DM组显著升高,TGF-β1、p-Smad2/3、collagen I和collagen III较DM组显著降低,miR-21水平较DM组显著降低(P 0. 05)。结论:ALA可抑制DM大鼠肾脏纤维化的发生发展,其机制可能是通过抑制TGF-β1和miR-21表达而上调Smad7蛋白的表达水平,使细胞外基质沉积减少。

Effect of alpha-lipoic acid on expression of miR-21/Smad7 and fibrosis in kidney of diabetic rats

AIM: To investigate the protective effect of alpha-lipoic acid (ALA) on the kidney of the rats with diabetes mellitus (DM), and to discuss the mechanism. METHODS: The DM rats were divided into normal control (NC) group, DM group and ALA group. After treated with ALA for 6 weeks, the rats were sacrificed to detect the relevant biochemical parameters, and the pathological changes of the kidney tissues were observed by HE staining and Masson staining. The protein levels of transforming growth factor-β1 (TGF-1), p-Smad2/3, Smad7, collagen I and collagen Ⅲ were determined by Western blot. In addition, the expression of microRNA-21 (miR-21) was detected by RT-qPCR. RESULTS: Compared with NC group, the kidney weight/body weight, blood glucose (BG), total cholesterol, triglyceride and 24-h urine protein were remarkably increased in DM group (P<0.05). The pathological observation of the kidney tissues showed fibrosis changes in DM group. The level of Smad7 was reduced in DM group, while the levels of TGF-β1, p-Smad2/3, collagen I, collagen Ⅲ and miR-21 in the kidney tissues were increased (P<0.05). After treatment with ALA for 6 weeks, all the relevant biochemical parameters were reduced except BG, and the renal fibrosis lesions were obviously alleviated. Compared with DM group, the levels of TGF-1, p-Smad2/3, collagen I, collagen Ⅲ and miR-21 in the kidney tissues were reduced in ALA group, while the level of Smad7 was increased (P<0.05).CONCLUSION: ALA may prevent the development of renal fibrosis in rats through restraining the expression of TGF-β1 and miR-21, increasing the levels of Smad7 protein, and reducing the deposition of extra cellular matrix.