Comparison of the Effect of Six Weeks of Aerobic and Resistance Training on miR-373 Gene Expression in Male Rats with Cardiomyopathy

Diabetic cardiomyopathy (DCM) is a functional, metabolic, and morphological deterioration of the myocardium caused by changes in glucose homeostasis caused by diabetes. miRs play a significant role in the occurrence of DCM. Reducing the overexpression of miR373 gene has a potential role in the appearance of this disease. Therefore, the purpose of this research was to compare the effect of six weeks of aerobic and resistance training on the expression of miR373 gene in mice with diabetic cardiomyopathy and male Wistar rats.

This research had a developmental goal, from the point of view of the experimental method and from the point of view of the laboratory execution method, with a post-test design. 36 healthy male Wistar rats with an average weight of 200 ± 20 grams and an age of 8 weeks were purchased from Pasteur Institute in Tehran. To induce diabetes, 50 mg/kg of streptozotocin (STZ) was injected intraperitoneally in a single dose to 27 rats. To confirm the validity of diabetes induction, glucose ≥ 200 mg/dl or hema index ≥ 3.5 were considered. According to research, diabetic cardiomyopathy occurs two months after the induction of diabetes. To confirm the occurrence of diabetic cardiomyopathy in the form of a pilot project, 3 heads of healthy rats (before the start of the research) and 3 heads of diabetic rats (after two months of becoming diabetic) were dissected and samples of myocardial tissue were taken. Rats with cardiomyopathy were randomly classified into four groups of 6 vertices (control, sham exercise, resistance exercise and aerobic exercise). A healthy group of 6 vertices was also considered for comparison with other groups. After two weeks of familiarization with the environment and learning to exercise, aerobic (running on a treadmill) and resistance (walking on an ascending ladder) training protocols were implemented for six weeks. 48 hours after the last training session (along with 12 hours of fasting), all rats were anesthetized using ketamine and xylazine and dissected and sampled from the left ventricular tissue. Real Time PCR was used to evaluate the expression of miR373 genes. For the statistical analysis of the data, ANOVA and T-correlated tests were used at the significance level of P ≤ 0.05.

Both exercise protocols led to a significant (P ≤ 0.05) decrease in fasting blood glucose (FBS) and insulin resistance index (HOMA-IR%). VO2peak (P: 0.1) of the aerobic group and 1RM (P: 0.73) of the resistance group increased significantly. The miR-373 gene expression level decreased in the control and sham diabetic groups compared to the healthy group, but increased in both exercise groups. But this increase was not significant (P > 0.05). It was also shown that resistance training had more significant changes on FBS and HOMA-IR indices compared to aerobic training (P = 0.001). Finally, aerobic and resistance training led to a significant increase in Vpeak (T = -4.9, P = 0.004) and 1RM (T = -7.68, P = 0.001).

Aerobic and resistance training improved the aerobic capacity and strength of the training groups, respectively. In addition, both exercises led to the improvement of diabetic complications (increased the expression level of miR-373), but aerobic exercise caused a better improvement of diabetic cardiomyopathy complications.