Effects of aging and/or training on antioxidant enzyme system in diaphragm of mice

We investigated the effects of aging and/or swimming training on the antioxidant enzyme system in diaphragm of mice. Young (2 months old) and old (26 months old) male mice were swimming-trained for 6 weeks (1 h/day, 5 days/week). Cu,Zn-Superoxide dismutase (Cu,Zn-SOD) activity was significantly upregulated with aging, and swimming training definitely enhanced the activity only in young mice. Neither aging nor swimming training had overt effect on Mn-SOD activity. Glutathione peroxidase activity in young mice was significantly increased after training, but not in old mice. Both of immunoreactive Cu,Zn-SOD and Mn-SOD were significantly increased with aging but were unaffected by swimming training. Consequently, physical training significantly enhanced the specific activity of Cu,Zn-SOD in young mice, but not in old mice. Meanwhile, swimming training significantly increased xanthine oxidase activity in both age groups, the extent of the increase being greater in old mice than in young mice. We concluded that the antioxidant enzyme system in mouse diaphragm trends to be upregulated with aging, but that swimming training improved the system only in young mouse diaphragm.