Effects of Diabetes, Insulin and Alpha-Lipoic Acid on Diabetic Myopathy
Posted: Monday. August 18, 2008
Background and Aims: The progression of diabetes mellitus is concomitant with decrease of the regenerative capacity of skeletal muscle and treatment with insulin can prevent futher atrophy of slow and fast skeletal muscles. The aim of this study was to explore the effectss of type 1 diabetes and its treatment with insulin plus antioxidant (alpha-lipoic acid – LA) on the the process of skeletal muscle regeneration because oxidative stress have been implicated in pathogenesis of diabetic myopathy. Material and methods: Diabetes was induced by streptozotocin. Wistar rats were divided in four groups: control, diabetes, diabetes treated with insulin and diabetes treated with insulin plus LA. Regeneration process was induced by injection of local anesthetic. Analysis od fibre cross areas and fibre type distribution was performed after 10 days and 4 weeks.
Results: Soleus muscle. After 4 weeks of regeneration , fiber type distribution of control group was similar to normal soleus without the regeneration. After 4 weeks of regeneration , the percentage and the fibre cross areas of type I and IIA of diabetic muscles, did not reach values of control and normal soleus without the process of regeneration. In the group treated with insulin and insulin plus LA, the morphometric analysis of muscle was similar to these in control group. Extensor digitorum longus muscle. After 4 weeks of experiment control muscles were completely regenerated. In diabetic untreated muscles after 4 weeks of diabetes the percentage of type I and IIA fibers was greater. The treatment with insulin and insulin plus LA prevented changes in fiber type distribution during all investigated periods. Insulin therapy, in all experimental periods, resulted in a significant increase in fibre cross areas all fibre types. Additional therapy with LA restored the cross areas all fibre types.
Conclusion: The additional use of antioxidant therapy with insulin have the potential benefit in the treatment of diabetic myopathy.