Whey Protein Mitigates Oxidative Stress Injury and Improves Protein Synthesis in Mouse Skeletal Muscle by Regulating the SIRT1/Nrf2/HO-1 Axis and AMPK/TSC2/mTOR/4EBP1 Pathway

Whey protein (WP) can improve muscle mass and strength. However, its effects and underlying molecular mechanism in promoting recovery from muscle damage caused by excessive physical exercise remains unknown. Therefore, the present study aimed to investigate the therapeutic effect of WP on skeletal muscle injury caused by exogenous oxidants and excessive physical exercise and the potential underlying mechanism. An oxidative stress injury model of mouse skeletal muscle cells was established using hydrogen peroxide (H₂O₂) and excessive physical exercise. The results revealed that WP effectively improved the migration and differentiation of C2C12 cells exposed to H₂O₂. Moreover, WP significantly increased the body weight of mice following excessive physical exercise. It also reduced food intake, improved behavioral parameters, enhanced skeletal muscle morphology and function, and promoted protein synthesis, thereby alleviating oxidative stress injury in skeletal muscles. The results further indicated that the mechanism underlying the mitigation of oxidative stress injury in skeletal muscles may involve the silent information regulator sirtuin 1 (SIRT1)/ NF-E2-related factor-2 (Nrf2)/ hemeoxygenase-1 (HO-1) axis. This axis could, in turn, activates the AMP-activated protein kinase (AMPK)/tuberous sclerosis complex subunit 2 (TSC2)/mammalian target of rapamycin (mTOR)/4E-binding protein 1 (4EBP1) pathway, thereby promoting protein synthesis and improving the physiological function of skeletal muscles. This study provides important insights into the role of WP in promoting recovery from muscle damage, offering a basis for future research on WP-based nutritional intervention strategies.