PDH调控的糖代谢途径对缺氧后复氧的大鼠肥大心肌细胞凋亡的影响

Effects of glucose metabolism mediated by PDH on apoptosis of hypertrophied cardiac myocytes during post-hypoxia reoxygenation

目的 探讨丙酮酸脱氢酶 (pyruvatedehydrogenase ,PDH)介导糖代谢途径对缺血再灌注肥大心肌细胞凋亡的影响。方法 应用血管紧张素Ⅱ (angiotensinⅡ ,AngⅡ ) +去甲肾上腺素 (norepinephrine ,NE)诱导体外培养的大鼠心肌细胞肥大 ,采用 [3 H] Leu掺入法和测定细胞表面积来鉴定心肌细胞肥大 ;通过体外培养心肌细胞的缺氧复氧模拟缺血再灌注模型 ;分别以二氯乙酸 (dichloroacetate ,DCA)和抗阿霉素A(AntimycinA)干预并采用同位素液闪记数法测定PDH活性 ;流式细胞术测定细胞caspase 3表达 ;TUNEL检测细凋亡率。结果 ①AngⅡ 0 1μmol/L +NE 1μmol/L使心肌细胞体积增大49 73 % ,[3 H] Leu掺入量增加 115 17% ,P <0 .0 5。②DCA和AntimycinA分别增强和抑制PDH活性 ,呈量效关系 ,而无明显时间依赖性。③DCA各组 10 0 μmol/L ,10 0 0 μmol/L ,10 0 0 0 μmol/L均能抑制caspase 3表达和降低细胞凋亡率 ,出现量效反应和时间依赖性。④AntimycinA各组 0 1μmol/L ,1μmol/L ,10 μmol/L均增强caspase 3表达和增加凋亡率 ,也出现量效反应和时间依赖性。结论 caspase 3表达和细胞凋亡率与PDH活性呈反向变化 ,PDH介导的糖代谢途径参与了缺氧后复氧的肥大心肌细胞的凋亡过程。

Objective To explore effects of glucose metabolism regulated by pyruvate dehydrogenase (PDH) on the apoptosis of hypertrophied cardiomyocytes during post-hypoxia reoxygen. Methods Cultured rat cardiomyocytes were induced to be hypertrophy by angiotensinⅡ (AngⅡ) and norepinephrine (NE), which was confirmed by [ 3H]-Leu incorporation in cardiomyocytes and detection surface area of cells. We established a model of post-hypoxia reoxygenation of cultured cardiac cells in vitro. Dichloroacetate (DCA) and antimycin A were added respectively, and then the activity of PDH was determined by liquid scintillation counting. We used the flow cytometer to assay caspase-3 expression in hypertrophic cardiomyocytes and TUNEL technology to assay the apoptotic rates of cardiac cells. Results ① Surface area of cells increased by 49.73% and [ 3H]-Leu incorporation by 115.17% Ang Ⅱ (0.1 μmol/L) plus NE (1 μmol/L), P<0.05. ② DCA and antimycin A respectively enhanced and inhibited the activity of PDH in dose- and time-dependent manners. ③ DCA at the doses of 100, 1 000, and 10 000 μmol/L inhibited caspase-3 expression and apoptotic rates in dose- and time-dependent manners. ④ Antimycin A at the doses of 100, 1 000, and 10 000 μmol/L inhibited caspase-3 expression and apoptotic rates of cells in dose- and time-dependent manners. Conclusion Caspase-3 expression and apoptotic rates of cardiomyocytes change inversely with PDH activity. Glucose metabolism regulated by PDH is involved in apoptotic process of hypertrophic cardiomyocytes during post-hypoxia reoxygenation.