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The Effects of Alpha-Lipoic Acid on Diabetic Muscle Regeneration Capacity

Skeletal muscle is an extremely heterogeneous tissue composed of four fibre types with different sensitivity to insulin action. Diabetes mellitus type 1 is associated with neuromyopathy. Increased oxidative stress and impaired antioxidant defence are important mechanisms in the pathogenesis of this diabetic complication. Regeneration capacity of skeletal muscle during diabetes mellitus is reduced. Since alpha-lipoic acid (LA) is potent biological antioxidant the aim of present study was to determine the influence of LA on the process of muscle regeneration. Two-months-old male Wistar rats were randomised to control group, untreated diabetes group and diabetes group treated with LA. Diabetes was induced by i.p. injection of streptozotocin (STZ). Regeneration process was induced in slow (m.soleus, SOL) and fast (m.extensor digitorum longus, EDL) skeletal muscles by injection of local anaesthetic, bupivacain. At intervals of 10 days and 4 weeks, morphometric analysis of skeletal muscles was performed. The percentage of type I fibres in diabetic SOL muscles was significantly lower in respect to control group after 4 weeks of diabetes. In the diabetic group treated with LA the percentage of type I and IIA are similar to those in control group. In diabetic soleus muscle treated with LA, the fibre cross areas of type I and type IIA were significantly higher after 4 weeks of treatment in respect to diabetic muscles. Diabetic untreated EDL muscles, 4 weeks after regeneration, showed statistically increased percentage of type IIX fibres. In diabetic EDL muscle treated with LA there was statistically more fibres of type I and IIB. In diabetic EDL muscle, the cross areas of all fibre types were significantly smaller than in control muscles. In diabetic group treated with LA the fibre cross areas were significantly higher than in diabetic group. Our results suggest that treatment with LA can restore fibre type distribution and cross sectional areas induced by diabetes mellitus in regenerating slow and fast skeletal muscles.

muscle regeneration; diabetes mellitus; Alpha-Lipoic Acid

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