[Effects of transcutaneous electric acupoint stimulation on plasma SOD and MDA in rats with sports fatigue].

Objective: To observe the effect of transcutaneous electric acupoint stimulation (TEAS) on plasma superoxide dismutase (SOD) and malondialdehyde (MDA) in rats with sports fatigue so as to explore its mechanisms in resisting exercise-induced fatigue.

Methods: Twenty-seven male adult SD rats were randomly divided into control group (n 9), model group (n=9) and TEAS group (n=9). Sports fatigue model was established by using treadmill method, i.e. forcing the rat to run 10 min at a speed of 10 m/min, 15 m/min, 20 m/min, 24 m/min and 28 m/min, once daily for 6 days. TEAS (continuous waves, 2 Hz, 5 mA) was applied to unilateral "Zusanli" (ST 36) for 30 min, once per day for 7 days. The exhausted exercise time from starting running to exhaustion was recorded on the 7th day and the lactate levels, SOD activity and MDA contents in plasma were measured by lactate oxidase method, xanthine oxidase method and thiobarbituric acid method respectively.

Results: The duration of exhausted exercise in model group and TEAS group were (56.00 +/- 12.27) min and (70.88 +/- 13.74) min respectively, displaying significant increase in exercise tolerance after TEAS (P<0.05). The lactate level and MDA content in model group were markedly higher than those in control group (P<0.05); while compared with model group, lactate and MDA contents in TEAS group were significantly lower (P<0.05), and plasma SOD activity in TEAS group was significantly higher (P<0.01). No significant differences were found in plasma lactate content between control and TEAS groups and in SOD activity between model group and control group (P>0.05). SOD/MDA of model group was significantly lower than those of control group and TEAS group (P<0.05, 0.01).

Conclusion: TEAS at "Zusanli"(ST 36) can effectively postpone exercise-induced fatigue by reducing accumulation of blood lactate, improving anti-oxidative ability and relieving lipid peroxidation in the rat.