中文摘要：

目的：研究不同强度跑台运动对AMPKα2三种不同基因状态鼠MEF2/GLUT4DNA结合活性及GLUT4基因表达的影响,以探讨运动提高骨骼肌MEF2/GLUT4DNA结合活性及GLUT4基因表达可能机制。方法：野生小鼠和AMPKα2高表达转基因小鼠,AMPKα2基因敲除小鼠各30只,分别随机分为安静对照组、低强度（12m/min）跑台运动组和高强度（20/min）跑台运动组。运动时间均为1h。运动后3h取材。Westernblot法测定AMPK（THr72）磷酸化水平。CHIP法测定MEF2/GLUT4DNA结合活性。Real-TimePCR法测定GLUT4mRNA含量。结果：1）野生鼠1h不同强度跑台运动后,GLUT4基因表达量显著增加的同时,伴随着骨骼肌核内MEF2/GLUT4DNA结合活性的显著增加;2）AMPKα2高表达转基因鼠1h不同强度跑台运动后,其骨骼肌细胞核内MEF2/GLUT4DNA结合活性及GLUT4基因表达量,均比野生鼠增加更为显著;3）AMPKα2敲除鼠1h不同强度跑台运动后,骨骼肌核内MEF2/GLUT4DNA结合活性显著低于野生鼠,但GLUT4基因表达量与野生鼠相比没有显著差异。结论：1）运动通过提高MEF2/GLUT4DNA结合活性而提高GLUT4表达;2）AMPKα2参与调解了运动诱导的MEF2/GLUT4DNA结合活性及GLUT4基因表达量的升高;3）虽然AMPKα2参与调节了运动诱导的MEF2/GLUT4DNA结合活性的提高,但机体还可以募集其他的信号通路代偿AMPKα2对GLUT4表达的调节作用。

英文摘要：

Purpose：The role of AMPK in regulating the exercise induced MEF2A binding to the GLUT4 promoter,and GLUT4 mRNA expression was investigated.Methods：Wild-type（WT;n=30）,AMPKα2 over-expression（OE;n=30）,and AMPKα2 knockout（KO;n=30） C57/BL mice were randomly divided into three groups：control group,low-intensity（12m/min） group and high-intensity（20m/min） group.Mice were killed after 3h of treadmill running completed by 60 min of continuous running on the experimental day.1） AMPKα-Thr172 phosphorylation by western blot.2） Total and nuclear MEF2A by western bolt.3） Bound MEF2A at the GLUT4 MEF2 cis-e,m lement by CHIP.4） GLUT4 expression by Real Time-PCR and Western blot.Results：Over-expression of AMPKα2,which was associated with higher AMPKα-P in exercise muscles,heightens the exercise-induced increase in MEF2A binding to the GLUT4 promoter and GLUT4 mRNA expression.Exercise-induced increases of GLUT4 mRNA expression,were normal in α2-KO muscles despite the reduced AMPK signaling and GLUT4 promoter-bound MEF2A.Conclusion：1）Exercise increases Glut4 expression by increase the binding of MEF2A to the Glut4 promoter.2）Exercise increases the binding of MEF2A to their binding sites on the Glut4 gene by an AMPK-dependent mechanism.3）AMPK activity during exercise is not indispensable for expression of GLUT4.