Abstract: This study investigated the effect of resveratrol on muscle fiber type transformation in bovine myotubes. Cell viability and related metabolic enzyme activities were measured by methyl thiazolyl tetrazolium (MTT) and colorimetric assays, and myogenic regulatory factors (MRFs), myosin heavy chains (MyHCs), and gene and protein expression related to mitochondrial biogenesis were determined. The results showed that resveratrol treatment significantly increased the gene expression of Myf5, Myf6, MyoG, and MyoD (P < 0.05) and promoted the differentiation of bovine myotubes. Resveratrol significantly increased slow MyHC expression and decreased fast MyHC expression, while upregulating the mRNA expression levels of MyHC I and MyHC IIa and downregulating the mRNA expression levels of MyHC IIx and MyHC IIb (P < 0.05). Resveratrol also significantly increased succinate dehydrogenase (SDH) and malate dehydrogenase (MDH) activity and decreased lactic dehydrogenase (LDH) activity (P < 0.05). In addition, resveratrol increased the gene and protein expression levels of silent information regulator 1 (SIRT1), peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α), nucleus respiratory factors-1 (NRF-1), mitochondrial transcription factor A (TFAM) (P < 0.05). Addition of the SIRT1 inhibitor 6-chloro-2,3,4,9-tetrahydro-1H-carbazole-1-carboxamide (EX527) significantly attenuated resveratrol-induced muscle fiber type transformation (P < 0.05), and the promoting effect of resveratrol on the gene and protein expression of SIRT1, PGC-1α, NRF-1, and TFAM (P < 0.05). Taken together, resveratrol can promote mitochondrial biogenesis and consequently muscle fiber type transformation by activating the SIRT1/PGC-1α signaling pathway.

Key words: resveratrol; bovine myotubes; silent information regulator 1/peroxisome proliferator-activated receptor-gamma coactivator-1α; muscle fiber type transformation; mitochondrial biogenesis