血管紧张素-(1-7)通过抑制活性氧激活的环氧合酶-2通路保护心肌细胞对抗高糖引起的损伤

Angiotensin-(1-7) protects cardiomyocytes against the high glucose-induced injury by inhibiting ROS-activated Cox-2 pathway

目的探讨活性氧(ROS)激活的环氧合酶-2(COX-2)通路在高糖(HG)损伤H9c2心肌细胞中的作用及血管紧张素-(1-7)[Ang-(1-7)]能否通过调控ROS激活的COX-2通路抑制HG引起的心肌细胞损伤。方法应用Western blot法检测COX-2蛋白的表达;细胞计数盒(CCK-8)测定细胞存活率;Hoechst 33258核染色检测凋亡细胞的形态及数量的变化;DCFH-DA染色荧光显微镜测定细胞内ROS水平;JC-1染色荧光显微镜照相测定线粒体膜电位(MMP)。结果应用1000μmol/L ROS清除剂(N-乙酰半胱氨酸,NAC)或1μmol/L Ang-(1-7)共处理H9c2心肌细胞12 h能显著地抑制HG对COX-2表达的上调作用;35 mmol/L葡萄糖(HG)处理心肌细胞24 h引起明显的损伤作用,使细胞存活率和MMP降低,凋亡细胞数量及细胞内ROS生成增多;Ang-(1-7)或COX-2抑制剂(NS-398)共处理心肌细胞明显地抑制上述HG引起的损伤作用。结论 Ang-(1-7)通过抑制ROS激活COX-2通路保护心肌细胞对抗HG引起的损伤。

Objective To investinate the roles of reactive oxygen species（ROS）-activated cyclooxygenase-2（COX-2） in high glucose（HG）-induced cardiomyocyte injury and whether Angiotensin-（1-7） [Ang-（1-7）] inhibits the HG-induced injury by modulating the ROS-activated COX-2 pathway in cardiomyocytes.Methods The expression of COX-2 was detected by Western blot assay; Cell viability was measured by cell counter kit（CCK-8）; The changes in morphology and amount of apoptotic cells were tested by Hoechst33258 nuclear staining; The intracellular level of ROS was assessed by DCFH-DA staining and photofluorography; The mitochondrial membrane potential（MMP） was analysed by JC-1 staining and photofluorography.Results Co-treatment of H9c2 cariac cells with HG and 1 μmol / L Ang-（1-7） or 1000 μmol / L N-acetyl-L-cysteine（NAC）,attenuated up-regulation of COX-2 expression induced by HG.Exposure of the cells to 35 mmol / L glucose（HG） for 24 h induced significant injuries,evidenced by decreases in cell viability and MMP,increases in the number of apoptotic cells and the intracellular level of ROS generation.The co-treatment of the cells with HG and Ang-（1-7） or NS-398（an inhibitor of COX-2） obviously attenuated the HG-induced injuries mentioned above.Conclusion Ang-（1-7）protects cardiomyocytes against the HG-induced injury by inhibiting ROS-activated COX-2 pathway.