抑制COX-2表达通过Akt/iNOS/NO信号通路发挥抗凋亡作用机制的研究

Inhibition of COX-2 protects against cardiomyocyte apoptosis via Akt/iNOS/NO pathway

目的探讨心肌缺血/再灌注损伤过程中环氧化酶-2(COX-2)的表达水平与细胞凋亡之间联系及作用机制。方法通过对心肌细胞进行缺氧/复氧(H/R)实验,模拟心肌缺血再灌注过程,检测COX-2及凋亡相关蛋白的表达水平;采用COX-2特异性抑制剂NS398对其活性进行抑制,观察细胞凋亡水平的变化,并研究其作用机制。结果与对照组相比,在H/R组中,Bcl2表达明显减少,cleaved capase-3的表达明显增强;在NS398预处理后,cleaved caspase-3的表达明显减少,Bcl2表达增强,TUNEL试验结果提示,NS398预处理明显减少阳性细胞的比例。结论在心肌细胞中,H/R刺激能够激活COX-2表达,并通过促凋亡途径导致细胞损伤;抑制COX-2活性能够激活Akt/iNOS/NO信号通路,并进而通过抗凋亡机制,发挥对心肌细胞的保护作用。

Objective To explore the potential relationship and mechanism between cyclooxygenase-2（COX-2）expression and apoptosis during myocardial ischemia/reperfusion injury（MI/RI）.Methods We simulated the process of MI/RI by hypoxia/reoxygenation（H/R）experiment in both H9C2 cell line and primary rat cardiomyocytes,and detected the expression of COX-2and apoptosis-related protein.Furthermore,COX-2expression was inhibited by NS398,COX-2specific inhibitor.Changes of cell apoptosis were detected,and the underlying mechanism was explored.Results Pre-treatment with NS398 significantly attenuated H/R-induced cell injury and apoptosis [increased expression of Bcl2 and reduced level of cleaved caspases-3and TUNEL-positive cells]in cardiomyocytes.Conclusion In cardiomyocytes,H/R stimulation will activate COX-2expression and induce cell damage through apoptotic pathway.Inhibition of COX-2will protect cardiomyocytes against apoptosis via Akt/iNOS/NO signaling pathway.