Effect of Sports on the Reduction of Cell Membtane Susceptibility, Antioxidant Defense and Oxidative Stress

The biological effects of potent oxidative agents in human body are under anti-oxidative control. Functional defects of organs may result from reactions of free radicals with the cell membrane. It is known that major targets of oxygen radicals are cell membrane lipids. Some reports indicate the role of peroxides in development of atherosclerosis. Human body tissues(eg.erythrocytes) contain major antioxidants including glutathione peroxidase and glutathione, hence normal erythrocytes are resistant to oxidative damage. Several controversial studies have demonstrated the effect of sport on improvement of antioxidants and prevention of oxidative damage. Our major objectives were to study the susceptibility of erythrocytes and to evaluate antioxidants such as glutathione peroxidase and glutathione in sports men and compare these variables with that of non-sports men. Patients and In this cross-sectional study 121 male subjects(80 sportsmen and 41 non sportsmen) have been studied. To evaluate the susceptibility of the erythrocytes, Malondialdehyde(MDA) was measured after they were exposed to H2O2. Glutathione was measured by use of SS Dithio-bis(2-Nitrobenzoic acid)(DTNB). The activity of glutathione peroxidase and Creatine phospho-kinase(CPK) were assessed by enzymatic methods and plasma total anti-oxidants were estimated by Ferric reducing ability of plasma(FRAP) method. For statistical analysis of quantitative and qualitative variables Chi-Square and student T test were used. Creatinine phosphokinase activities in sportsmen were significantly higher. Erythrocytes obtained from non-sportsmen were more susceptible. Since, malondialdehyde resulting from incubation of erythrocytes with hydrogen peroxide in sportsmen(with catalase inhibition: 625.23±132.71nmol/gHb and without catalase inhibition: 521.74±125.05nmol/gHb) was significantly lesser than malondialedehyde of non-sportsmen.(P<0.02 and P<0.01 respectively). Plasma total antioxidant levels, glutathione peroxidase activity and glutathione in the cells were not significantly different. Although anti-oxidative power in sportsmen is not different but it seems lipids of erythrocyte membranes are less susceptible to oxidative stress as compared to nonsportmen.