The Effect of Endurance and Resistance Training on Apoptosis Activity and Collagen Deposition in Heart Tissue of Diabetic Rats

Diabetes causes chronic problems in the structure and function of tissues, such as apoptosis and fibrosis in addition to glycemic disorders. In this study the effect of 8 weeks of endurance and resistance training on various signaling pathways of apoptosis and tissue fibrosis of the heart of diabetic rats was investigated.

Thirty Wistar rats, approximately 8-10 weeks old, weight about 210-250 grams, received intraperitoneal injection of diabetic streptozotocin and were randomly divided into three groups: endurance training, resistance training and control group. The rats of the endurance training group were trained on the treadmill for 8 weeks, 5 days a week with intensity of vo2Max 60-80%. The resistance training group was trained on the ladder with a slope of 85 degrees and with a weight equals to 30-100% of their body weight. Forty eight hours after the last training session, blood samples were collected and ventricular tissues of mice were extracted. Glucose, insulin, serum insulin resistance index and Bcl-2, Bax, caspase 8 gene expression levels and Bax to Bcl-2 ratio were evaluated. Masson's trichrome and hematoxylin-eosin staining methods were used for histological examination of diabetic rat's heart structure to detect fibrosis.

There was a significant decrease in Bax gene expression and the ratio of Bax to Bcl-2, and also there was a significant increase in Bcl-2 and caspase 8 in the endurance and resistance training groups in comparison with the control group. The rate of cardiomyocyte fiber rupture in the endurance and resistance groups was less than the control group, and the presence of lymphocyte cells was observed in some fibers in the control group. (p≤0.05).

The results showed that high-intensity resistance training and moderate-intensity endurance training can prevent tissue fibrosis caused by collagen deposition in diabetes, and these two types of training can reduce the factors involved in apoptosis both in the internal and external pathways. On the other hand, this training intensity can be used as an effective non-pharmacological method to reduce the problems of apoptosis and fibrosis caused by diabetes in the heart tissue.