In skeletal muscle, the composition of the fiber types has a profound impact on athletic performance, such as endurance or strength output. The proportions of muscle fiber types have also been associated with certain diseases, including dyskinesia, obesity and insulin resistance. Genistein, a natural estrogen, has been demonstrated to regulate fatty acid oxidation and insulin sensitivity in skeletal muscle. However, it is unknown whether genistein can regulate skeletal muscle fiber types. Furthermore, the mechanism of its effect on skeletal muscle energy metabolism is not entirely clear. In this study, in vivo and in vitro experiments were used to explore the effect of genistein on the muscle fiber-type transitions and muscle metabolism. The results indicated that genistein not only promotes skeletal muscle development but increases the expression of slow muscle fibers in mice as well. It was also demonstrated that genistein altered the ratios of fiber type and promoted mitochondrial biogenesis in C2C12 myoblasts. Interestingly, the expression of miR-222 was decreased by genistein, and it was demonstrated that this microRNA targets the PGC1α gene. In C2C12 myoblasts, miR-222 appears to regulate fiber type conversion and mitochondrial biogenesis. However, this function was significantly reduced following genistein treatment. These results suggest that miR-222 may be involved in the regulation of genistein on skeletal muscle fiber and muscle metabolism, and genistein may be used to improve muscle health.

在骨骼肌中，纤维类型的组成会对运动表现（如耐力或力量输出）产生深远影响。肌肉纤维类型的比例也与某些疾病有关，包括运动障碍，肥胖症和胰岛素抵抗。金雀异黄素是一种天然的雌激素，已被证明可以调节骨骼肌中的脂肪酸氧化和胰岛素敏感性。但是，染料木黄酮是否可以调节骨骼肌纤维类型尚不清楚。此外，其对骨骼肌能量代谢的作用机理尚不完全清楚。在这项研究中，体内和体外实验用于探讨染料木黄酮对肌纤维类型转变和肌肉代谢的影响。结果表明，染料木黄酮不仅促进骨骼肌发育，而且还增加了小鼠慢肌纤维的表达。还证明了染料木黄酮改变了C2C12成肌细胞中纤维类型的比率并促进了线粒体的生物发生。有趣的是，染料木黄酮降低了miR-222的表达，并证明了该microRNA靶向PGC1α基因。在C2C12成肌细胞中，miR-222似乎在调节纤维类型的转化和线粒体的生物发生。然而，在染料木黄酮治疗后，该功能显着降低。这些结果表明，miR-222可能参与了染料木黄酮对骨骼肌纤维和肌肉代谢的调控，