This study investigated the effects of resveratrol and miR-22-3p on muscle fiber type conversion in mouse C2C12 myotubes. Here we showed that resveratrol significantly increased the protein level of slow myosin heavy chain (MyHC) and the activities of succinic dehydrogenase and malate dehydrogenase, as well as markedly decreased the protein level of fast MyHC and the activity of lactate dehydrogenase. Immunofluorescence staining showed that resveratrol remarkably upregulated the number of slow MyHC-positive myotubes and downregulated the number of fast MyHC-positive myotubes, suggesting that resveratrol promoted muscle fiber type conversion from fast-twitch to slow-twitch in C2C12 myotubes. We also showed that miR-22-3p had an opposite function on muscle fiber type conversion and resveratrol was able to repress the expression of miR-22-3p. Furthermore, AMP-activated protein kinase (AMPK) inhibitor Compound C and miR-22-3p mimics could attenuate and eliminate muscle fiber type conversion from fast-twitch to slow-twitch cause by resveratrol, respectively. Together, we provided the first evidence that resveratrol promotes muscle fiber type conversion from fast-twitch to slow-twitch via miR-22-3p and AMPK/SIRT1/PGC-1α pathway in C2C12 myotubes.

这项研究调查了白藜芦醇和miR-22-3p对小鼠C2C12肌管中肌纤维类型转化的影响。在这里，我们显示白藜芦醇显着增加了慢肌球蛋白重链（MyHC）的蛋白质水平以及琥珀酸脱氢酶和苹果酸脱氢酶的活性，并显着降低了快速MyHC的蛋白质水平和乳酸脱氢酶的活性。免疫荧光染色显示，白藜芦醇显着上调了慢MyHC阳性肌管的数量，而下调了快速MyHC阳性肌管的数量，这表明白藜芦醇促进了C2C12肌管中肌纤维类型从快搏转变为慢肌。我们还表明，miR-22-3p在肌肉纤维类型转换中具有相反的功能，白藜芦醇能够抑制miR-22-3p的表达。此外，AMP激活的蛋白激酶（AMPK）抑制剂化合物C和miR-22-3p模拟物可分别减弱和消除白藜芦醇引起的从快速抽动到慢速抽动引起的肌纤维类型转换。在一起，我们提供了第一个证据，即白藜芦醇通过miR-22-3p和AMPK / SIRT1 /PGC-1α途径促进C2C12肌管中肌肉纤维类型从快肌转变为慢肌。