Acute exercise induced mitochondrial H₂O₂ production in mouse skeletal muscle: Association with p^66Shc and FOXO3a signaling and antioxidant enzymes

Exercise induced skeletal muscle phenotype change involves a complex interplay between signaling pathways and downstream regulators. This study aims to investigate the effect of acute exercise on mitochondrial H₂O₂ production and its association with p66Shc, FOXO3a, and antioxidant enzymes. Male ICR/CD-1 mice were subjected to an acute exercise. Muscle tissues (gastrocnemius and quadriceps femoris) were taken after exercise to measure mitochondrial H₂O₂ content, expression of p66Shc and FOXO3a, and the activity of antioxidant enzymes. The results showed that acute exercise significantly increased mitochondrial H₂O₂ content and expressions of p66Shc and FOXO3a in a time-dependent manner, with a linear correlation between the increase in H₂O₂ content and p66Shc or FOXO3a expression. The activity of mitochondrial catalase was slightly reduced in the 90 min exercise group, but it was significantly higher in groups with 120 and 150 min exercise compared to that of 90 min exercise group. The activity of SOD was not significantly affected. The results indicate that acute exercise increases mitochondrial H₂O₂ production in the skeletal muscle, which is associated with the upregulation of p66Shc and FOXO3a. The association of p66Shc and FOXO3a signaling with exercise induced H₂O₂ generation may play a role in regulating cellular oxidative stress during acute exercise.