Coffee is a widely consumed beverage worldwide and is believed to help prevent the occurrence of various chronic diseases. However, the effect of coffee on skeletal muscle hypertrophy, differentiation and the mechanisms of action responsible have remained unclear. To investigate the effect of coffee on skeletal muscle hypertrophy, mice were fed a normal diet or a normal diet supplemented with 0.3% coffee or 1% coffee. Coffee supplementation was observed to increase skeletal muscle hypertrophy, while simultaneously upregulating protein expression of total MHC, MHC2A, and MHC2B in quadricep muscle. Myostatin expression was also attenuated, and IGF1 was upregulated with subsequent phosphorylation of Akt and mTOR, while AMPK phosphorylation was attenuated. Coffee also increased the grip strength and PGC-1α protein expression, and decreased the expressions of TGF-β and myostatin in tricep muscle. Coffee activated the MKK3/6-p38 pathway and upregulated PGC-1α, which may play a role in promoting myogenic differentiation and myogenin expression in C2C12 cells. These results suggest that coffee increases skeletal muscle function and hypertrophy by regulating the TGF-β/myostatin – Akt – mTORC1.

中文翻译：

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喝咖啡促进骨骼肌肥大和成肌细胞分化

咖啡是世界范围内被广泛使用的饮料，被认为有助于预防各种慢性疾病的发生。然而，咖啡对骨骼肌肥大，分化和负责的作用机制的影响尚不清楚。为了研究咖啡对骨骼肌肥大的影响，给小鼠喂食正常饮食或补充0.3％咖啡或1％咖啡的正常饮食。补充咖啡可增加骨骼肌肥大，同时上调四头肌中总MHC，MHC2A和MHC2B的蛋白质表达。肌生长抑制素的表达也被减弱，IGF1被随后的Akt和mTOR磷酸化上调，而AMPK的磷酸化被减弱。咖啡还增加了抓地力和PGC-1α蛋白的表达，降低了三头肌中TGF-β和肌生长抑制素的表达。咖啡激活了MKK3 / 6-p38途径并上调了PGC-1α，这可能在促进C2C12细胞的肌原性分化和肌原蛋白表达中发挥了作用。这些结果表明，咖啡可通过调节TGF-β/肌生成抑制素– Akt – mTORC1来增强骨骼肌功能和肥大。