Biochemical assessments of oxidative stress, erythrocyte membrane fluidity and antioxidant status in professional soccer players and sedentary controls.

BACKGROUND: Physical exercise is characterized by an increase in oxygen consumption by the whole body. This leads to a decrease in antioxidant levels that could promote both an increase in the markers of lipoprotein peroxidation and damage to the erythrocyte membrane with consequent modification of membrane fluidity.
MATERIALS AND METHODS: Different markers of oxidative stress, erythrocyte membrane fluidity and antioxidant status were determined in 20 professional soccer players and 20 sedentary controls. Plasma lipoperoxides and kinetics of Cu-stimulated plasma peroxidation were measured together with hydrosoluble (albumin, uric acid and vitamin C), liposoluble (vitamin E and bilirubin) and enzymatic (superoxide dismutase and glutathione peroxidase) serum antioxidants. Erythrocyte membrane rigidity was determined by measuring fluorescence anisotropy (rs) of the fluorescent probe 1, 3, 5 diphenylexatriene.
RESULTS: The sportsmen showed higher levels of the following plasmatic antioxidants: ascorbic acid (P<0.0001), uric acid (P<0.0001), alpha-tocopherol (P=0.03) and superoxide dismutase activity (P=0.0001). According to this evidence, the lipoperoxide levels (P=0.0158), the duration of the latency phase of plasma peroxidation (P=0.0123) and erythrocytes membrane fluidity (P=0.0152) were found to be significantly higher in the soccer players. DISCUSSION: Athletes undergoing regular and adequate training show improved antioxidant status together with a more fluid membrane status, which could contribute to improving both peripheral resistance to insulin and all the functional metabolic interchanges in the cellular membrane.