Anti-Diabetic Effect of Long-Term Aerobic Training in Type 2 Diabetic Rats with Emphasis on Adiponectin Expression in Subcutaneous Adipose Tissue

Background and objectives: Clinical evidence has demonstrated the important role of adiponectin in insulin signaling pathways in target tissue. The aim of this study was to determine effects of aerobic training on insulin sensitivity, glucose level, and adiponectin expression in subcutaneous adipose tissue of type 2 diabetic rats. Methods: Type 2 diabetes was induced in 14 male wistar rats by intraperitoneal injection of nicotine amide and streptozotocin. The rats were randomly divided into an exercise group (n=7) and a control group (n=7). The rats in the exercise group performed aerobic training in from of treadmill running, five sessions a week, for 12 weeks. Subjects in the control group did not perform any training. Glucose level, insulin level, insulin sensitivity, and adiponectin expression in subcutaneous adipose tissue were determined at baseline and 48 hours after the lasting training session. Independent t-test was used for comparing the variables between the study groups. Results: Aerobic training resulted in a significant increase in serum insulin (p=0.006), insulin sensitivity (p=0.003), and adiponectin expression in subcutaneous adipose tissue (p=0.037) compared with the control group. In addition, the training caused a significant decrease in fasting glucose level compared with the control group (p<0.001). Conclusion: Based on these findings, the decrease in blood glucose may be attributed to the improvement of adiponectin-dependent insulin signaling pathways in adipose tissue in response to aerobic training. However, more cellular-molecular studies are needed to understand the mechanisms responsible for these changes.