Antioxidant enzyme activities and malondialdehyde levels related to aging

Abstract

Background: Free oxygen radicals have been proposed as important causative agents of aging. We have evaluated age-related changes in antioxidant enzyme activities and lipid peroxidation. Methods: We measured erythrocyte superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and plasma malondialdehyde (MDA) levels. One hundred and seventy six healthy subjects were divided into five groups: Group 1 ( n=25; 0.2–1 year-old), Group 2 ( n=28; 2–11 years), Group 3 ( n=23: 12–24 years), Group 4 ( n=40; 25–40 years), Group 5 ( n=60: 41–69 years). Results: SOD activities in Group 5 were significantly lower than in the other groups ( P<0.001). GPx and CAT activities and MDA levels in Group 5 were significantly higher than the other groups ( P<0.001, respectively). CAT activity in Group 4 was significantly higher than group 1 and group 2 (respectively, P<0.001), and in group 3 was high compared to Group 2 ( P<0.001). There were negative correlations between SOD activities and age ( P<0.001). Conversely, there were positive correlations between CAT, GPx and MDA levels and age ( P<0.001). CAT activities of women in Group 2 were found to be high compared to the men ( P<0.05). MDA levels of women in Group 5 were higher than in the male groups ( P<0.001). Conclusions: We found age-related differences in erythrocyte antioxidant enzyme activities. Furthermore, peroxidative injury is raised in the aging process.