The effect of high intensity interval training on complex mammalian target of Rapamycin 1 (mTORC1) pathway in Flexor hallucis longus muscle (FHL) of streptozotocin-induced diabetic rats

The most well-known mechanism for regulating complex mammalian target of rapamycin 1 (mTORC1) pathway activity is the insulin/IGF-1-dependent pathway in skeletal muscles. The role of high intensity interval training (HIIT) exercise has not yet been studied on this important pathway in protein synthesis among people with type 2 diabetes. The purpose of the present study was to investigate the effects of HIIT on mTORC1 pathway in Flexor hallucis longus muscle (FHL) of streptozotocin (STZ)-induced diabetic rats. In this experimental study, sixty male Sprague–Dawley rats with a weight of 260±20 g were randomly assigned into two equal groups including control group (n= 8) and HIIT trained group (n=8) after inducing diabetes in them by STZ and nicotinamide. The latter group of rats were trained in accordance with the training program for 4 weeks (4 sessions per week). Control groups received no exercise intervention. Furthermore, rats did not receive any insulin therapy during the study period. Independent t-test was used to assess the difference between the groups. Differences were considered significant at p<0.05. There was a significant increase in the value of AKT1 (p<0.005), mTORC1 (p<0.0001), P70S6K1 (p<0.008) and 4E-BP1 (p<0.001) proteins in the HIIT trained group as compared to the control group. Given the increase in the content of these proteins (AKT1, mTORC1, P70S6K1 and 4E-BP1) in the FHL skeletal muscle tissue of type 2 diabetic subjects and their important role in protein synthesis, HIIT's exercise may be considered as an important approach for increasing protein synthesis or muscle hypertrophy in these individuals.