Alterations of mTOR pathway and autophagy in early type 2 diabetic cardiomyopathy in rats

Abstract

Objective: To investigate the alterations of mTOR signaling pathway and autophagy in the development of type 2 diabetes and early diabetic cardiomyopathy and to study their roles in pathogenesis of diabetic myocardium. Methods: A type 2 diabetes rat model was established by injection of streptozocin after five-week of high fat diet. The rats were randomly divided into control group, experiment group of 2 weeks and experiment group of 4 weeks. Alterations of mTOR, p-mTOR, S6K1, Beclin-1 and LC3-Ⅱ expression in myocardium were determined by Western blot and immunohistochemistry. Results: Compared with the control group, the expression of mTOR, p-mTOR, S6K1, Beclin-1 and LC3-Ⅱ level increased significantly in the experiment group of 2 weeks. The expression of p-mTOR and S6K1 increased significantly in the experiment group of 4 weeks compared with those of the experiment group of 2 weeks. Conclusions: mTOR signaling pathway is activated in early diabetic myocardial injury via autophagy. The findings may provide a new therapeutic target for diabetic cardiomyopathy.