大鼠心肌缺血预处理中COX_2基因表达及作用的研究

The function and expression of COX_2 gene in late phase of preconditioning in rat cardiomyocyte

目的探讨大鼠心肌细胞缺血预处理时COX2 mRNA、COX2 蛋白的表达及作用。方法以RT PCR法观察缺血预处理后不同时间点COX2 mRNA的表达 ,以用Westernblotting法测定缺血预处理后 2 4小时、4 8小时和 72小时心肌细胞中COX2 表达量。分 3组 (对照组、缺血预处理组和NS398组 ) ,以LDH释放和台盼蓝排斥试验判断心肌细胞损伤程度。结果缺血预处理后心肌细胞COX2 mR NA表达量在 1小时始上升 (P <0 .0 1) ,3小时达高峰 ,随后开始降低 ,至 2 4小时到缺血预处理前水平 ;缺血预处理后 2 4小时 ,COX2 蛋白表达增高 ,4 8小时达高峰 ,72小时后降低 ;缺血预处理组的LDH释放较对照组少、细胞存活率高 ;NS398组LDH释放、细胞存活率与对照组相当。结论缺血预处理后COX2 mRNA和COX2 增高 ,COX2

Objective To explore the function and expression of COX 2 mRNA and COX 2 in late phase of ischemic preconditioning. Methods The expression of COX 2 mRNA and COX 2 activity were determinated by polymerase chain reaction and western blotting techniques respectively in different time after ischemic preconditioning. The injury of cardiomyocyte was assessed by LDH release and trypan blue uptake in three groups Group control, Gyoup IPC,Group NS 398 .Results The expression of COX 2 mRNA was markedly increased at 1h after ischemic preconditioning, remained elevated at 3h , and returned to the level before ischemic preconditioning by 24h. The amount of COX 2 increased at 24h after ischemic preconditioning, remained elevated at 48, and returned to near the level before ischemic preconditioning at 72h. The LDH was higher in Group IPC than Group control, the difference of the amount of LDH was not significant between Group NS 398 and Group control ( P >0.05). Conclusion In late phase of preconditioning, the expression of COX 2 mRNA and COX 2 increased significantly in rat cardiomycyte. COX 2 mediates the cardioprotective effects of the late phase of ischemic preconditioning.