Effects of ginsenoside Rg3 on fatigue resistance and skeletal muscle mitochondrial function in rats exposed to a simulated altitude of 5 000 m

Objective To observe the effects of ginsenoside Rg3 (Rg3) in improving fatigue resistance and functionality of skeletal muscle mitochondria in rats at a simulated high altitude. Methods Forty adult male SD rats were randomly divided into 4 groups (n=10), namely the normal group (NG), Rg3-treated normal group (NG+Rg3), model group (MG), and Rg3-treated model group (MG+Rg3). In the latter 2 groups, the rats were exposed to a stimulated altitude of 5 000 m in a hypobaric chamber, and on a daily basis, the rats were taken from the chamber for intragastric administration of 20 mg/kg Rg3 (completed in 1 h). After 15 d of treatment, forced swimming test was performed and 30 min later blood samples were collected from the abdominal aorta for testing the levels of total cholesterol (TC), plasma triglyceride (TG), lactate dehydrogenase (LDH), blood glucose (GLU), blood ammonia (BA) and blood urea nitrogen (BUN); The quadriceps were quickly isolated for detecting malondialdehyde (MDA), Mn-superoxide dismutase (Mn-SOD) and the activity of compound Ⅲ and Ⅳ in the respiratory chain. Results Rg3 treatment significantly increased the swimming time (P < 0.05 or 0.01) and serum levels of TC, TG, LDH and GLU (P < 0.05 or 0.01) and enhanced Mn-SOD activity and mitochondrial respiratory chain complex Ⅲ and Ⅳ activities (P < 0.01) both in rats kept in normal conditions and in those exposed to the simulated high altitude. Rg3 also significantly decreased serum BUN level and MDA content in the skeletal muscle mitochondria in rats exposed to the simulated high altitude (P < 0.01). Conclusion Rg3 can extend forced swimming time, improve the biochemical indexes related to fatigue, and enhance free radical clearance and energy supply of skeletal muscle mitochondria of rats.