Electron leak causes proton leak in skeletal muscle mitochondria in exercise-induced fatigue

Using an animal model of exercise-induced fatigue by incremental exercise to exhaustion on a motor-driven treadmill, the changes of the mitochondrial proton leak and electron leak in mitochondria of skeletal muscle from rats immediately after exhaustive exercise were observed. The results showed that, in exercise-in-duced fatigue conditions, superoxide anions of rat skeletal muscle mitochondria increased;State 4 respiration rate significantly accelerated and respiration control ratio clearly decreased. Results show that, in the condition of exercise-induced fatigue, the increased mitochondrial proton leak and electron leak may be important factors that cause the decrease in coupling of oxidative phosphorylation. Our results provide evidence supporting a hypothesis that electron leak causes proton leak in mitochondria.