N-乙酰半胱氨酸对脂多糖诱导大鼠肝细胞内质网应激的抑制作用

N-acetyl-L-cysteine inhibits endoplasmic reticulum stress induced by lipopolysaccharide in rat hepatocytes

目的:探讨N-乙酰半胱氨酸(N-acetyl-L-cysteine,NAC)对脂多糖(lipopolysaccharide,LPS)诱导大鼠肝细胞内质网应激的影响。方法:培养大鼠肝细胞系BRL细胞,用NAC或LPS分别或共同处理BRL细胞,其中共同处理时把NAC加入培养液中预处理1 h再给予LPS处理肝细胞。用锥虫蓝拒染法检测细胞存活率;Hoechst33258染色荧光显微技术检测肝细胞凋亡的形态学变化;免疫印迹法检测内质网应激标志蛋白GRP78及凋亡相关蛋白CHOP、Caspase-12和Caspase-3的表达。结果:与溶剂对照组比较,LPS能时间依赖性地引起肝细胞细胞活力显著降低和细胞凋亡增多,诱导内质网应激标志蛋白GRP78表达明显上调;NAC预处理抑制LPS引起细胞存活率降低和细胞凋亡增多,并且能显著抑制LPS诱导的GRP78及凋亡相关蛋白CHOP、Caspase-12和Caspase-3表达上调。结论:NAC通过阻断LPS诱导的肝细胞内质网应激而减轻肝细胞损伤。

Objective： To investigate the effect of N-acetyl-L-cysteine（NAC） on endoplasmic reticulum stress（ERS） induced by lipopolysaccharide（LPS） in rat hepatocytes. Methods： Rat hepatocyte line BRL cells were cultured and treated with LPS, NAC in respective or combine manners, NAC was added into cell medium 1 h prior to LPS exposure. The cell viability was evaluated using trypan blue exclusion test. The cyto-nuclear morphological changes of apoptosis cells was detected by using the fluorescent dye Hoechst33258. Expressions of GRP78, CHOP, Caspase-12 and Caspase-3 were detected by Western Blot. Results： Compared with vehicle,LPS caused a significant decrease in cell viability and enhancement in apoptosis in a time-dependent manner, Western Blot showed that the expression of GRP78 protein increased significantly along with the treatment of LPS. Pretreatment with NAC significantly not only inhibited LPS-induced the decrease of cell viability, but also reversed the increase of apoptosis induced by LPS. Furthermore, NAC preconditioning obviously blocked the upregulation of GRP78, CHOP, Caspase-12 and Caspase-3 expression induced by LPS. Conclusion： NAC protected against the hepatocyte injuries induced by LPS through the inhibition of ERS.