The effects of exercise on contractile properties of skeletal muscle in type I diabetic rats

It is well known that regular physical activity has the beneficial effects on several pathological states such as obesity, cardiovascular diseases, and diabetes. The present study aims to investigate the effects of 4 week swimming exercise on contractile properties of skeletal muscle in type 1 diabetic male rats. A total of 36 male adult Wistar Albino rats were used in the study. The groups in the experiment were generated as diabetes, diabetes + exercise, exercise and control. A single dose (50 mg/kg, intraperitoneal) of streptozotocin (STZ) was administered to induce type 1 diabetes. After STZ injection, the rats in group diabetes+exercise and exercise only were subjected to 1 h daily swimming exercise for 4 weeks. The initial and final blood glucose levels and weekly body weight were recorded. In situ isometric tension responses of gastrocnemius muscle were determined at the end of the experiment. The mean and standard error of the mean were determined for each variable. Shapiro-Wilk and Levene tests were used to analyse the normal distribution and homogeneity of variance of the data. Repeated measurements of variance analysis were performed for body weight and glucose values. One-way ANOVA was conducted to evaluate the effects of diabetes and exercise. Single twitch force, maximal isotonic tetanic contraction, and initial tension of fatigue protocol decreased in diabetic rats (p<0.01). Time to peak tension and single twitch half relaxation time were not affected by diabetes and/or exercise (p=0,265 ve p=0,066, respectively). Response of single twitch force obtained three minutes after fatigue protocol decreased depending on diabetes but exercise restored this impairment (p=0.002). It was found that diabetes has negative effects on, contractile properties of skeletal muscle and exercise could have beneficial effects on this process.