【摘要】 目的　探讨氧化应激损伤心肌细胞的分子机制。方法　采用0.5mmol/L过氧化氢(hydrogenperoxide,H2O2)作用于原代培养的新生大鼠心肌细胞;末端标记检测细胞凋亡;Westernblot检测蛋白质含量;免疫组化检测NF-κB在细胞内的分布。结果　①H2O2损伤3h,心肌细胞死亡率和乳酸脱氢酶(LDH)释放率均较对照组明显升高(P<0.01);②H2O2损伤24h,末端标记发现大量凋亡细胞;Westemblot示NF-κB内源性抑制蛋白Ⅰ-KB(inhibitorKB,I-KB)在H2O2损伤5min即减少,15min时减至最低,而后逐渐恢复;免疫组化显示H2O2损伤0.5h可引起心肌细胞中NF-κB从胞浆向胞核移位;与单纯损伤组比,NF-κB抑制剂吡咯烷二硫代氨基甲酸盐(pyrrolidinedithiocarbamate,PDTC)能明显降低心肌细胞LDH释放率(P<0.01)。结论　在H2O2所致心肌细胞损伤中,既有坏死,又有凋亡的发生,而NF-κB/Ⅰ-κB信号通路的激活可能介导了H2O2所致的心肌细胞损伤。更多还原

【Abstract】 Objective:This study was designed to investigate the role of NF-κB/I-κB in cardiomyocyte injury during the oxidative stress. Methods:Injury of neonatal rat cardiomyocytes was induced by exposure to 0.5 mmol/L hydrogen peroxide (H 2O 2) for different durations. Cardiomyocyte necrosis and apoptosis were determined by cell death rate, LDH release rate and terminal deoxynucleotidyl transferase-mediated biotin-dUTP nick-end labeling (TUNEL) respectively. The change of I-κB was assayed by Western Blot. The translocation of NF-κ B from cytoplasm to nucleus was observed by immunohistochemical analysis. Results: Exposure to 0.5 mmol/L H 2O 2 resulted in neonatal ratcardiomyocyte necrosis and apoptosis as shown by increase of cell death rate, LDH release rate and TUNEL positivity respectively. Level of I-κB,an endogenous inhibitory protein of NF-κB, began to decrease after 5 min of H 2O 2 treatment, reached nadir at 15 min, and recovered at 1 h. The translocation of NF-κB from cytoplasm to nucleus in cardiomyocytes was observed after exposure to H 2O 2 for 0.5 h. Pyrrolidine dithiocarbamate (PDTC), an inhibitor of NF-κB, could attenuate H 2O 2-induced increase of LDH release rate in cardiomyocyte ( P <0.01). Conclusion:H 2O 2 could induce both necrosis and apoptosis of cultured neonatal rat cardiomyocytes,which could be mediated by activation of NF-κB/I-κB pathway.更多还原