糖尿病大鼠肾组织中PTEN/AKT/mTOR通路对自噬的调控作用

目的:观察糖尿病大鼠肾组织中PTEN和自噬水平的变化,探讨糖尿病肾病中PTEN/AKT/m TOR通路对自噬的调控机制。方法:将SD大鼠随机分为正常对照组(NC组)和糖尿病组(DM组),每组各8只。用链脲佐菌素复制DM大鼠模型。于成模后10周处死大鼠后测定相应生化指标和肾脏指数,免疫组化观察肾小管上皮细胞PTEN蛋白的表达部位;Western blotting法检测肾组织LC3、PTEN及PTEN/AKT/m TOR通路的变化;realtime PCR检测肾组织PTEN的mRNA表达水平。结果:DM组的血糖、24 h尿蛋白量和肾脏指数均显著高于NC组(P0.05)。与NC组相比,DM组大鼠肾组织的LC3I和LC3II水平明显降低(P0.05)。PTEN主要分布于肾小管上皮细胞中,DM组PTEN蛋白的表达水平明显低于NC组(P0.05)。DM大鼠肾组织中,PTEN/AKT/m TOR通路的活性增高。结论:糖尿病大鼠肾脏组织中细胞自噬水平下降,而参与自噬调控的PTEN/AKT/m TOR通路活性升高,提示其自噬水平的变化可能受到PTEN/AKT/m TOR通路的调节。

Effects of PTEN/AKT/mTOR signalling pathway on regulation of autophagy in renal tissues of diabetic rats

ATM:To observe the expression change of PTEN and autophagy in the renal tissues of diabetic rats, and to explore the regulatory mechanism of PTEN/AKT/mTOR pathway to autophagy in diabetic nephropathy. METHODS: The Sprague-Dawley rats were randomly divided into normal control group and diabetic group (8 in each group). The diabetic rat model was established by injection of streptozotocin. The biochemical and kidney indexes were measured after the model of diabetic nephropathy was successfully established. The expression location of PTEN in the renal tubular epithelial cells was observed by the method of immunohistochemistry. The protein levels of autophagy-related protein LC3, PTEN and PTEN/AKT/mTOR signalling molecules were determined by Western blotting. The mRNA expression of PTEN was detected by real-time PCR. RESULTS: The blood glucose, 24 h urine protein and kidney index in diabetic group were all obviously higher than those in control group. Compared with control group, the protein levels of LC3I and LC3II in diabetic group were obviously decreased. PTEN was mainly located in the renal tubular epithelial cells. Compared with control group, the protein expression of PTEN was significantly down-regulated in diabetic group. Furthermore, the activity of PTEN/AKT/mTOR pathway increased in diabetic nephropathy rats. CONCLUSION: The level of autophagy in renal tissues of diabetic rats is decreased, whereas the activity of PTEN/AKT/mTOR pathway is increased. The level of autophagy may be mediated by PTEN/AKT/mTOR pathway.