Acta Pharmacologica Sinica 2005 Aug; 26 (8): 992-999; doi: 10.1111/j.1745-7254.2005.00155.x

Aim: To assess the effects of L-arginine (L-Arg) supplementation on pulmonary oxidative stress and antioxidant defenses in rats after exhaustive exercise.

Methods: Rats were randomly divided into four groups: sedentary control (SC), sedentary control with L-Arg treatment (SC+Arg), exhaustive exercise with control diet (E) and exhaustive exercise with L-Arg treatment (E+Arg). Rats in groups SC+Arg and E+Arg received a 2% L-Arg diet. Rats in groups E and E+Arg underwent an exhaustive running test on a motorized treadmill. Pulmonary oxidative stress indices [xanthine oxidase (XO), myeloperoxidase (MPO), and malondialdehyde (MDA)] and antioxidant defense systems [superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione reductase (GR), and glutathione (GSH)] were investigated in this study.

Results: L-Arg supplementation significantly reduced exercise-induced elevations of XO and MPO activities in lung. L-Arg reversed the exercise-induced increase in SOD and GR activities, but increased CAT and GPX activities. L-Arg administration also significantly increased the GSH levels in plasma.

Conclusion: L-Arg supplementation can prevent elevations of XO and MPO activities in the lung and favorably influence pulmonary antioxidant defense systems after exhaustive exercise.

Keywords: L-arginine; oxidative stress; xanthine oxidase; myeloperoxidase; exhaustive exercise; lung