This research was conducted in order to study the influence of long-time and short-time intensive exercise on the level of SOD mRNA expression in human lymphocytes. Eight male university students (aged 20-22) undertook a 30-km run, while 10 others (aged 18-20) undertook a maximal exercise test using an aero bike. All 18 subjects were members of the track and field club. Blood samples were obtained before and 30 minutes after both types of exercise. Expression of manganese-SOD (Mn-SOD) mRNA and copper-zinc SOD (Cu/Zn-SOD) mRNA in the lymphocytes was measured. The results of the 30-km run showed a significant increase in the expression levels of both Mn-SOD mRNA and Cu/Zn-SOD mRNA (p<0.05 in both cases). In the maximal exercise test, Cu/Zn-SOD mRNA expression levels were not significantly altered; however, Mn-SOD mRNA expression levels showed a significant increase 30 minutes after the test, in comparison with those before the test (p<0.05). These results suggest that SOD mRNA in lymphocytes is enhanced not only during longtime but also during short-time intensive exercise, probably due to the induction of oxidative stress. It is also suggested that Mn-SOD mRNA in lymphocytes is more susceptible to the effects of exercise than Cu/Zn-SOD mRNA.
