热休克基因表达对过氧化氢所致肺泡巨噬细胞损伤的保护作用

THE PROTECTIVE ROLE OF HEAT SHOCK GENE EXPRESSION ON HYDROGEN PEROXIDE INDUCED PULMONARY ALVEOLAR MACROPHAGES

经Ｎｏｒｔｈｅｒｎ及Ｗｅｓｔｅｒｎ印迹分析发现热休克预处理（４２℃，２ｈ）使肺泡巨噬细胞（ＰＡＭｓ）中热休克蛋白（ＨＳＰ）７０ｍＲＮＡ增多，ＨＳＰ７０合成增加，且获得抵抗Ｈ２Ｏ２损伤的能力。用放线菌酮和放线菌素Ｄ分别从蛋白合成及基因转录水平阻断热休克蛋白基因的表达，能取消热休克对Ｈ２Ｏ２所致ＰＡＭｓ损伤的保护效应。提示热休克系通过使热休克蛋白基因表达增强，ＨＳＰ７０合成增多，从而保护Ｈ２Ｏ２所致的ＰＡＭｓ损伤。

The aim of this study is to determine whether heat induced heat shock gene expression in rat pulmonary alveolar macrophages(PAMs) would protect PAMs against hydrogen peroxide (H 2O 2) mediated cell killing. In response to sublethal heat shock at 42℃ for 2h, the cells synthesized heat shock protein 70kD(HSP70) and other different molecular weight heat shock proteins, which were detected with gel electrophoresis after [ 35 S] methionin labeling cellular protein and Western blotting analysis in PAMs. Northern blot analysis showed the induction of HSP70 mRNA with heat shock treatment. Futhermore, with heat shock, there was a significant increment of survival cells after H 2O 2 (1,2,3mmol·L -1 , 45min) exposure. This increase was blocked both by Cycloheximide and by Actinomycin D, and was associated with inhibition of synthesis of HSP70 protein and transcription of HSP70 mRNA. These results strongly suggest that expression of heat shock gene(especially HSP70 gene) plays an important role in the intracelluar mechanism of cytoprotection against H 2O 2 in rat PAMs.