三磷酸腺苷后处理通过RISK信号通路和mKATP减轻兔心肌缺血再灌注损伤

Role of RISK Signal Pathway and mKATP in ATP-induced Cardioprotection Against Myocardial Ischemia/Reperfusion Injury

目的探讨再灌注损伤挽救激酶(RISK)信号通路和线粒体ATP敏感性钾通道(mKATP)在三磷酸腺苷(ATP)后处理减轻兔心肌缺血再灌注损伤中的作用。方法选择60只雄性大耳白兔随机为缺血再灌注损伤组(IRI组)、ATP后处理组、PI3K抑制剂Wortmannin+ATP后处理组(Wortmannin+ATP组)、ERK1/2抑制剂PD98059+ATP后处理组(PD98059+ATP组)、选择性mKATP抑制剂5-HD+ATP后处理组(5-HD+ATP组),每组12只,建立心肌缺血再灌注模型。采用依文思蓝和四氮唑蓝双重染色测定心肌梗死面积,TUNEL法检测心肌细胞凋亡,Western blot检测心肌Akt、p-Akt、ERK1/2及p-ERK1/2蛋白的表达。结果 ATP后处理组心肌梗死面积、心肌细胞凋亡指数明显低于IRI组(P<0.01)。Wortmannin+ATP组、PD98059+ATP组和5-HD+ATP后处理组心肌梗死面积、心肌细胞凋亡指数与IRI组比较差异无统计学意义。Western blot检测显示,ATP后处理组p-Akt、p-ERK1/2表达水平明显高于IRI组(P<0.05)。结论 ATP后处理可通过缩小心肌梗死面积和减少心肌细胞凋亡发挥对缺血再灌注心肌的保护作用,其机制可能与RISK信号通路及mKATP有关。

Aim To investigate the roles of reperfusion injury salvage kinase （RISK） signaling pathway and mitochondrial ATP-sensitive potassium channels （mKATP） in the postconditioning effect of adenosine triphosphate （ATP） for rabbits with myocardial ischemia/reperfusion injury （IRI）. Methods Sixty white male rabbits were exposed to 40 min of ischemia followed by 180 min of reperfusion. Rabbits were intravenously injected 3 mg/kg of ATP （ ATP group） or saline （ IRI group） immediately after reperfusion within 30 min. The Wortmannin ＋ ATP, PI）98059 ＋ ATP, and 5- hydroxydecanoic acid sodium salt （5-HD） ＋ ATP groups were respectively injected with Wortmannin （PI3K inhibitor, 0. 6 mg/kg）, PD98059 （ERK1/2 inhibitor, 0. 3 mg/kg）, and 5-HD （a mKATP blocker, 5 mg/kg） 5 rain before ATP admin- istration. Myocardial infarction size was measured by Evans blue and NBT staining. Myocardial apoptosis index was determined by TUNEL methods. Expressions of myocardial Akt, p-Akt, ERK1/2 and p-ERK1/2 were detected by Western blot. Results The myocardial infarction size and apoptosis index were significantly lower in ATP group than those in IRI group, Wortmannin ＋ ATP group, PD98059 ＋ ATP group and 5-HD ＋ ATP group （P 〈 0. 01 ）. Western blot showed that the expressions of p-Akt and p-ERK1/2 were significantly higher in ATP group than those in other four groups （P 〈0. 05）.Conclusions ATP postconditioning attenuated IRI by reducing the myocardial infarction size and apoptosis, which is mediated through activation of RISK signaling pathway and opening of mKATP.