中文摘要：

目的探讨单磷酸腺苷激活蛋白激酶（AMPK）对体外培养心肌细胞蛋白降解的影响。方法分离培养新生Sprague-Dawley大鼠心肌细胞，用AMPK特异性激动剂5氨基咪唑4-甲酰胺-1-β-D-呋喃核糖苷（AICAR）（2．0mmol／L）、抑制剂CompoundC（0．5mmol／L）干预，按干预方式分为：对照组、AICAR组、Compound C组及AICAR＋Compound C组。Western blot检测心肌细胞AMPK、p-AMPK蛋白的表达水平；高效液相色谱法检测细胞培养基中3-甲基组氨酸（3MH）的浓度。结果各组心肌细胞总AMPK蛋白水平没有明显变化，AICAR可上调心肌细胞PAMPK蛋白水平，Compound C下调心肌细胞PAMPK蛋白水平，并抑制AICAR对P—AMPK蛋白的上调作用。AMPK激活后心肌细胞3-MH释放增加，而AMPK活性受到抑制后，3-MH释放减少。结论AMPK激活能促进心肌细胞的蛋白降解。

英文摘要：

Objective To investigate the effects of adenosine monophosphate activated protein kinase（AMPK） on protein degradation in cardiomyocytes in vitro. Methods Neonatal Sprague Dawley rat cardiomyocytes were isolated and cultured,and then treated with specific AMPK activator 5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside（AICAR） （2. 0 mmol/L） and inhibitor Compound C （0.5 retool/L）. Cells were divided into Control, AMPK,Compound C and AMPK＋ Compound C group according to treatment manner. Western blot was employed to assay levels of AMPK and p AMPK protein in cardiomyocytes, and high performance liquid chromatography was used to detect 3-methylhistidine（3-MH） concentration in culture medium. Results Levels of total AMPK protein of cardiomyocytes in each group showed no obvious changes. AICAR treatment up-regulated level of pAMPK protein,whereas Compound C treatment down regulated it and reversed the up-regulation effect of AICAR on p-AMPK protein. AMPK activation increased 3 MH releasing from cardiomyocytes, whereas AMPK suppression decreased it. Conclusion AMPK activation promotes protein degradation in cardiomyocytes.