缺氧复氧诱导大鼠心肌细胞内质网应激反应

目的:观察大鼠心肌细胞缺氧复氧时内质网应激蛋白表达的改变及其意义,以探讨心肌缺血再灌注损伤与内质网应激的关系.方法:原代培养乳鼠心肌细胞,缺氧5.5 h后复氧2～24 h制备缺氧复氧损伤模型,用Western blot和RT-PCR方法测定内质网应激蛋白GRP78表达水平.2-脱氧葡萄糖作为本实验的阳性对照,2-脱氧葡萄糖孵育心肌细胞10 h,用Western blot和RT-PCR检测GRP78表达水平.结果:缺氧复氧处理的心肌细胞活力减低,胞内乳酸脱氢酶漏出.与对照组比较,缺氧复氧组心肌细胞内质网应激蛋白GRP78在蛋白及mRNA水平表达均于复氧后2 h开始增加,4 h达峰值,蛋白水平为对照组的142%,mRNA水平为对照组的200%,表达的增加可持续到复氧24 h.结论:缺氧复氧可以诱导心肌细胞内质网应激.

Hypoxia/reoxygenation induced endoplasmic reticulum stress in cultured neonatal rat cardiomyocyte

Objective: To investigate the effect of hypoxia/reoxygenation on endoplasmic reticulum stress in cultured neonatal rat cardiomyocytes. Methods: Neonatal rat cardiac myocytes in primary culture were exposed to hypoxia for 5.5 hours and subsequently reoxygenation for 2-24 hours. Western blot and RT- PCR were applied to monitor the expression change of GRP78(glucose regulated protein 78). 2-deoxy-D-glucose(2-DG) was the positive control of this study. Then Western blot and RT- PCR were used to examine the expression of GRP78. Results: Cell viability was decreased obviously after hypoxia/reoxygenation. Compared with untreated cells, the GRP78 content of the cells had increased significantly in the hypoxia/reoxygenation cells. The level of GRP78 protein and mRNA elevated from the points of 2 hours to 24 hours after reoxygenation, and increased most obviously at the point of 4 hours after reoxygenation.(4 hours: protein level 142% of the control, mRNA level 200%). 2-DG could induce the increasing expression of GRP78 in a concentration-dependent manner from 10-50 mmol/L. Conclusion: Hypoxia/reperfusion can induce endoplasmic reticulum stress in rat cardiomyocytes.