NADPH氧化酶亚单位nox-1在心肌细胞急性缺氧复氧损伤时的变化及心肌营养素-1的作用

摘要

AIM: To observe the change of subunit of NADPH oxidation enzyme complex nox - 1 protein in cardiocyte hypoxia - reoxygenation injury and the role of cardiotrophin -1.METHODS: Cardiomyocytes from the hearts of 1 -3 d old neonatal rats were prepared by a modified method. Five groups were included in the study: control; hypoxia/ reoxygenation; hypoxia/reoxygenation + CT - 1; CT - 1 + hypoxia/reoxygenation + LY294002 (PIK3/Akt inhibitor) ; CT -1 + hypoxia/reoxygenation + PD98059 (ERK inhibitor) ; CT - 1 + hypoxia/reoxygenation + DMSO. The concentration of CT -1 was 10 μg/L. The survival rate of myocytes was evaluated by MTS method. Apoptosis, mitochondrial permeability transition pore ( △ψm) and reactive oxygen species ( ROS) were detected by flow cytometry. Nox - 1 protein was determined by Western blotting. RESULTS: Apoptosis of cardiomyocytes and the level of ROS (19.7% ±1.4% vs 2.1% ± 0.5% , 14.07% ± 1.25% vs 3.54% ± 0.86% , P < 0.05 ) increased markedly after hypoxia/reoxygenation, but cardio-myocyte survival rate and the level of △ψm (40.55% ±4.25% vs 86.28% ±7.15% , P <0.01) decreased significantly. The expression of nox - 1 protein was upregulated markedly. With CT - 1 intervention, cardiomyocyte survival rate increased markedly, apoptosis, both ROS and expression of nox - 1 protein reduced significantly. The level of △ψm increased obviously. The effect of CT - 1 was inhibited by LY294002.No significant effect was observed on cells survival in DMSO group, which confirmed that LY294002 was specifically involved in blocking the protective effect of CT - 1.CONCLUSION : The expression of subunit of NADPH oxidation enzyme complex nox - 1 protein is upregulated markedly in cardiocyte hypoxia - reoxygenation injury. CT - 1 protects cardiac cells against hypoxia - reoxygenation injury by downregulating the expression of nox -1 protein to decrease the level of ROS.%目的:探讨心肌细胞急性缺氧复氧损伤时NADPH氧化酶亚单位nox-1的变化及心肌营养素-1的作用.方法:用改良的方法培养出生1-3 d的乳鼠心肌细胞,分为6组:(1)对照组;(2)缺氧复氧组;(3)缺氧复氧+CT-1组;(4)缺氧复氧+CT-1+LY294002组 (PIK3/Akt 阻断剂);(5)缺氧复氧+CT-1+PD98059组(ERK 阻断剂);(6)缺氧复氧+CT-1+助溶剂DMSO组. CT-1 的浓度为10 μg/L.MTS法测定心肌细胞的存活率,四氯四乙基苯丙咪唑基羰化青碘化物(JC1)检测心肌细胞线粒体膜电位(Δψm),二氯荧光黄双乙酸盐(DCFH-CA)检测细胞活性氧(ROS),流式细胞仪检测心肌细胞凋亡率.Nox-1蛋白采用Western blotting检测.结果:缺氧复氧培养后心肌细胞凋亡率及细胞内ROS较对照组明显增加,分别是(19.7%±1.4% vs 2.1%±0.5%, 14.07%±1.25% vs 3.54%±0.86%, P<0.05),而心肌细胞存活率显著降低,线粒体膜电位(Δψm)下降;nox-1表达明显升高.CT-1处理的心肌细胞,较缺氧复氧组心肌细胞存活率明显上升 (87.0%±7.3%),而心肌细胞凋亡率及细胞内ROS 显著减少,Δψm水平增加,nox-1蛋白表达下调.而CT-1的这些作用能被PIK3/Akt和ERK阻断剂抑制.结论:心肌细胞急性缺氧复氧损伤时NADPH氧化酶亚单位nox-1表达上调,而心肌营养素-1能通过下调nox-1表达,发挥对心肌细胞保护作用.