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.