Influence of Resistance Training on IL-15 mRNA Expression and the Protein Content in Slow and Fast Twitch Muscles of Diabetic Rats

Resistance exercise training represents an effective interventional strategy to augment muscle mass, strength, and function in diabetes. It has been demonstrated that IL-15 (Interleukin-15) can act as an anabolic factor for skeletal muscle, influencing protein metabolism. It has also been suggested that IL-15 could regulate peripheral glucose metabolism. Our aim was to investigate whether resistance training has any effect on IL-15 expression and protein of skeletal muscles in rats with diabetes. Rats were divided into the control, the training, and the streptozotocin induced diabetic and diabetic training groups. Training groups performed resistance training exercise which consisted of climbing a 1 m ladder with weight added to the tail. IL-15 Gene expression of soleus and Flexor Hallucis Longus muscles was analyzed using real time. Skeletal muscle protein of IL-15 was measured by ELIZA method. The results of this study indicate that resistance training provided an anabolic stimulus sufficient to maintain the Flexor Hallucis Longus muscle mass of the diabetic training group. IL-15 mRNA levels in soleus were increased in the diabetic training group. Protein levels of IL-15 increased in the training and diabetic training groups in both skeletal muscles. Having a high content of mitochondria and relying on an oxidative pathway, soleus muscle was found to be more affected by diabetes. The lack of correlation of IL-15 mRNA and protein levels is partly due to transcriptional and translational blocks, which are present in the IL-15 gene sequence.