Akt/FoxO Signaling Pathway Mechanism of Resveratrol Regulating Oxidative Stress-Induced Fast-Twitch Transformation in Bovine Myotubes

Optimizing the distribution of myofiber types is an important strategy for improving beef quality. To explore the effect of resveratrol on myofiber type transformation in bovine myotubes and its mediating mechanism via the Akt/FoxO signaling pathway, MTT assay was used to determine the effects of different concentrations of resveratrol, wortmannin (a PI3K inhibitor), and SC79 (an Akt activator) on cell viability and their effective concentrations. An oxidative stress model was established by treating bovine myotubes with 400 μmol/L H₂O₂ for 24 h. Real-time quantitative fluorescent PCR (qPCR) was used to measure the mRNA expression levels of myofiber type marker genes (MyHC Ⅰ, MyHC Ⅱa, MyHC Ⅱx, and MyHC Ⅱb) and key genes of the Akt/FoxO signaling pathway (PI3K, Akt, FoxO1, and FoxO3). Concentration gradient experiments showed that 10 μmol/L resveratrol had the optimal regulatory effect on myofiber types under oxidative stress, significantly reversing the expression trends of the above genes (P<0.05). qPCR analysis revealed that resveratrol treatment significantly upregulated the mRNA expression of positive regulators of the Akt/FoxO pathway (PI3Kα, PI3Kβ, Akt1, and Akt2) and oxidative metabolism-related genes (MEF2C and PGC-1α), while inhibiting the transcription of negative regulators (FoxO1 and FoxO3) (P<0.05). Western blot experiments further confirmed that resveratrol increased PI3K protein expression and the phosphorylation levels of Akt, FoxO1, and FoxO3, while reducing the total protein content of FoxO1 and FoxO3 (P<0.05). Wortmannin significantly blocked these regulatory effects and attenuated promotion effect of resveratrol on slow-twitch myofiber protein and inhibition effect of fast-twich myofiber protein (P<0.05). Additionally, H₂O₂ treatment suppressed PI3K/Akt pathway activity, while co-treatment of resveratrol and SC79 restored normal pathway function. The results showed that resveratrol effectively reversed the oxidative stress-induced shift toward fast-twitch myofibers, promoted slow-twitch myofiber gene expression, and inhibited fast-twitch myofiber gene expression through the activation of the Akt/FoxO signaling pathway. This study aimed to investigate the mechanism of resveratrol in oxidative stress-induced myofiber type transformation in bovine myotubes via the Akt/FoxO signaling pathway, elucidate its action pathway for improving the edible quality of beef, and provide theoretical support for the application of natural active substances in the quality regulation of livestock and poultry meat.