Amendments of Antioxidant Enzyme Status in Different Skeletal Muscle Fibers under Age induced Oxidative Stress Conditions with Reference to Exercise Training

The purpose of the present investigation was to ascertain the influence of exercise training and aging on antioxidant enzyme status in functionally different skeletal muscle fiber types. Wistar strain albino rats of two age groups (3months young and 18months moderately aged/old) were divided into two experimental groups from each age and treated as sedentary control (SC) and exercise trained (ExT; 23m/min, 30min/day, 5days/week for 12 weeks). After completion of the last training session, the antioxidant capacity was evaluated by the assay of total superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione reductase (GR) and glutathione (GSH) content in the rat hind limb muscle fibers of soleus (SOL), red gastrocnemius (RG) and white gastrocnemius (WG). The results revealed that the activities of all antioxidant enzymes and GSH content were decreased in SOL, RG and WG muscle fibers of old rats compared to young rats. Whereas, the same parameters were up-regulated with exercise training in all muscle fibers. However, the exercise induced elevation in SOD and CAT activities was greater in older rats than the young rats. This elevation even in old muscle fibers with exercised may help to cope from age induced oxidative stress. The results obtained in the current investigation are discussed in the light of functional physiology of the muscle fiber types. From this study it was concluded that 12 weeks period of treadmill exercise training has beneficial in preventing the age-associated amendments in antioxidant machinery of different locomotor muscle fiber types.