PI3K-Akt-eNOS信号通路在间歇性低氧减轻大鼠心肌缺血/再灌注损伤中的作用

Effect of PI3K-Akt-eNOS signaling pathway on reducing myocardial ischemia-reperfusion injury after intermittent hypoxia in rats

目的探讨间隙性低氧环境下,磷酯酰肌醇-3激酶/蛋白激酶B/内皮型一氧化氮合酶信号通路(PI3K-Akte NOS)在大鼠心肌缺血/再灌注损伤中的作用机制。方法 64只大鼠随机分为4组,假手术组(n=16)、缺血/再灌注组(n=16)、缺血/再灌注组-间歇性低氧组(n=16)、间歇性低氧-缺血/再灌注-磷脂酰肌醇3-激酶抑制剂组(n=16)。采用球囊结扎冠状动脉方法制作心肌缺血再灌注动物模型,将老鼠暴露在低氧循环制作间隙性低氧动物模型,实验处理结束后,通过TUNEL法检测心肌细胞凋亡指数,Western-Blot方法检测磷酸化AKT蛋白(p-Akt)、磷酸化e NOS(p-e NOS)蛋白表达。结果与缺血/再灌注组比较,间歇性低氧+缺血/再灌注组心肌细胞凋亡指数为(21.73±4.56)%,心肌细胞凋亡指数减少,磷酸化AKt蛋白及磷酸化e NOS蛋白分别为(1.228±0.269)、(1.427±0.375),表达均升高,各组差异均有统计学意义(P<0.05);与间歇性低氧+缺血/再灌注组比较,间歇性低氧-缺血/再灌注组大鼠+磷脂酰肌醇3-激酶抑制剂组大鼠心肌为(30.84±3.65),凋亡指数升高,磷酸化AKt蛋白及磷酸化e NOS蛋白分别为(0.624±0.146)、(0.842±0.246),表达均降低,各组差异均有统计学意义(P<0.05)。结论在间歇性低氧状态下,PI3K-Akt-e NOS信号通路可以减少心肌细胞凋亡,在心肌缺血/再灌注损伤中具有保护机制。

Objective To investigate the effect of phosphatidylinositol-3 kinase/protein kinase B/endothelial nitric oxide synthase （PI3K-Akt-eNOS） signaling pathway on reducing myocardial ischemia-reperfusion injury after intermittent hypoxia in rats. Methods 64 rats were randomly divided into 4 groups： sham operation group（n=16）, ischemia-reperfusion group（n=16）, ischemia-reperfusion-intermittent hypoxia group（n=16）, intermittent hypoxia-ischemia-reperfusion-phos- phatidylinositol 3-kinase inhibitor group （n=16）. The animal model of myocardial ischemia and reperfusion was estab- lished by balloon ligation of coronary artery. The rats were exposed to hypoxic circulation to produce intermittent hypoxic animal models. After the end of the experiment, the apoptotic index of myocardial cells was detected by TUNEL method, and the expression of phosphorylated Akt protein （p-Akt） and phosphorylated eNOS （p-eNOS） protein was detected by Western-Blot method. Results Compared with ischemia-reperfusion group, the apoptotic index of myocardial cells was（21.73±4.56）% in intermittent hypoxia＋ischemia-reperfusion group. The myocardial cell apoptosis index was decreased, and phosphorylated Akt protein and phosphorylated eNOS protein were（1.228±0.269）, （1.427±0.375） respectively. The expressions were all increased, and the differences between groups were statistically significant（P〈0.05）; compared with intermittent hypoxia＋ischemia-reperfusion group, the myocardium of rats was （30.84±3.65）% in intermittent hypoxia＋ischemia-reperfusion group＋phosphatidyllnositol 3-kinase inhibitor group. The apoptosis index was increased, and the phosphorylated AKt protein and phosphorylated eNOS protein were（0.624±0.146）, （0.842±0.246） respectively. The expressions were all decreased and the differences between groups were statistically significant（P〈0.05）. Conclusion Under the status of intermittent hypoxia, PI3K-Akt-eNOS signaling pathway can reduce myocardial ischemiareperfusion injury by reducing the apoptosis of myocardial cells.