核转录因子-κB在热休克预处理抑制过氧化氢所致心肌细胞损伤中的作用

目的探讨热休克预处理抑制氧化应激损伤心肌细胞的分子机制。方法采用1mmol/L的过氧化氢(H2O2)作用于原代培养的新生大鼠心肌细胞;用总抗氧化能力检测试剂盒及福林酚法检测心肌细胞中总抗氧化能力的变化;用蛋白质免疫印迹法(Westernblot)检测热休克蛋白70(HSP70)、αB晶状体蛋白、核转录因子κB(NFκB)抑制物(IκB)含量;免疫组化检测NFκB及HSP70在细胞内的分布情况。结果1与H2O2(1mmol/L,3h)损伤组比,热休克预处理组(43℃1h,恢复6h)的总抗氧化能力明显增加(P均<0.01);2心肌细胞经热休克预处理(43℃1h)后3h,HSP70、αB晶状体蛋白、IκBα的表达均增加,6～12h达高峰,并可维持至24h;3与正常心肌细胞比较,H2O2(1mmol/L)处理的心肌细胞中IκBα的含量明显下降,而热休克预处理则可抑制H2O2所致的这种变化;4H2O2(1mmol/L,30min)可使心肌细胞胞质中的NF-κB及HSP70向胞核移位,若先经热休克预处理(43℃1h,恢复6h)则可使这种移位显著减少。结论热休克预处理可抑制H2O2所致的心肌细胞损伤,其保护作用可能与其诱导HSP70、αB晶状体蛋白及IκBα的表达,从而抑制NF-κB的活化有关。

Roles of nuclear factor-κB in heat shock pretreatment to abate cardiomyocyte injury induced by hydrogen peroxide

OBJECTIVE: To investigate the role of nuclear factor-kappaB (NF-kappaB) in heat shock pretreatment to abate cardiomyocyte injury induced by hydrogen peroxide (H(2)O(2)). METHODS: The primary generation of cultured neonatal rat cardiomyocytes were injured by exposure to 1 mmol/L H(2)O(2) for different durations. The total antioxidant in cardiomyocytes was detected. The changes in heat shock protein 70 (HSP70), alphaB-crystallin, inhibitor of NF-kappaB (I-kappaB) were assayed by Western-blotting. The translocation of NF-kappaB and HSP70 from cytoplasm to nucleus was observed by immunohistochemical analysis. RESULTS: (1)Compared with H(2)O(2) (1 mmol/L, 3 h) treated cells, cells subjected to heat shock pretreatment showed significant increase in total antioxidant capability (all P<0.01). (2)Western blot analysis demonstrated that heat shock pretreatment could induce expression of HSP70, alphaB-crystallin and I-kappaB. (3)Heat shock pretreatment inhibited H(2)O(2)-mediated I-kappaB degradation. (4)Immunohistochemical analysis showed that heat shock pretreatment could abate HSP70 and NF-kappaB translocation from cytoplasm to nucleus. CONCLUSION: Heat shock pretreatment could protect cardiomyocytes against H(2)O(2)-induced injury, and its mechanism might involve expression of HSP70, alphaB-crystallin and I-kappaB, which could inhibit H(2)O(2) -mediated NF-kappaB activation.