Melatonin Attenuates Oxidative Stress After an Exercise-induced Skeletal Muscle Damage

This study investigated whether, 24 hours after the exercise-induced muscle damage protocol (EIMDP), melatonin administration performed 30 minutes prior to the protocol exhibited responses about inflammatory and redox status. Control (CG), exercised (EG), and exercised+melatonin (EMG) groups were submitted to the incremental test through swimming exercise to determine the intensity of the maximal aerobic capacity (iMAC). Melatonin (10 mg kg^-1) was administered, and after 30 min, the EIMDP was induced through swimming exercise (10 sets of 1 min with 30-s interval at 120% of iMAC, followed by 20 minutes continuous exercise at 100% of iMAC). The animals were euthanized 24 hours after the EIMDP. No effect on superoxide dismutase but lower activities (p<0.05) of glutathione S-transferase for EMG in relation to EG and of catalase for EMG in relation to CG were observed. EMG showed lower (p<0.05) carbonylated protein and lipid peroxidation in relation to EG and CG, respectively. Hematoxylin-eosin (HE) demonstrated higher connective tissue for EG in relation to EMG. Integrated Biomarker Responses version 2 attested the melatonin capacity in reducing antioxidant enzyme activity and muscle oxidative damage. This study demonstrated the protective role of melatonin in reducing muscle oxidative stress caused after 24 hours of the EIMDP.