Evaluation of mitochondrial respiratory chain activity in muscle healing by low-level laser therapy

Background: Recent studies demonstrate that low-level laser therapy (LLLT) modulates many biochemical processes, especially the decrease of muscle injures, the increase in mitochondrial respiration and ATP synthesis for accelerating the healing process. Objective: In this work, we evaluated mitochondrial respiratory chain complexes I, II, III and IV and succinate dehydrogenase activities after traumatic muscular injury. Methods: Male Wistar rats were randomly divided into three groups (n = 6): sham (uninjured muscle), muscle injury without treatment, muscle injury with LLLT (AsGa) 5 J/cm(2). Gastrocnemius injury was induced by a single blunt-impact trauma. LLLT was used 2, 12, 24, 48, 72, 96, and 120 hours after muscle-trauma. Results: Our results showed that the activities of complex II and succinate dehydrogenase after 5 days of muscular lesion were significantly increased when compared to the control group. Moreover, our results showed that LLLT significantly increased the activities of complexes I, II, III and IV and succinate dehydrogenase, when compared to the group of injured muscle without treatment. Conclusion: These results suggest that the treatment with low-level laser may induce an increase in ATP synthesis, and that this may accelerate the muscle healing process. (C) 2009 Published by Elsevier B.V.