内质网应激参与细胞脂肪变性的研究

Endoplasmic Reticulum Stress Participated in Fatty Degeneration Induced by Free Fatty Acids in vitro Hepatic Steatosis Model

目的阐述内质网应激是否参与了游离脂肪酸(FFA)诱导的细胞脂肪变性模型的脂变形成过程,并探讨二甲双胍对内质网应激的潜在影响。方法将HepG2细胞按培养液成分不同分为4组:空白对照组,二甲双胍组,游离脂肪酸组以及干预组。HepG2细胞培养24h后,检测细胞活力和脂质含量。以反转录PCR和Western blotting检测各组葡萄糖调节蛋白78(GRP78)和固醇调节元件结合蛋白1c(SREBP1c)表达水平。结果游离脂肪酸组诱导的细胞脂肪变性的HepG2细胞的甘油三酯、GRP78和SREBP1c的mRNA和蛋白表达水平均明显升高。同时,干预组的甘油三酯、GRP78和SREBP1c的mRNA和蛋白的表达水平均有所下降,但是没有显著性差异。结论内质网应激参与了游离脂肪酸诱导的细胞脂肪变性模型的脂变形成过程。内质网应激可能是非酒精性脂肪肝发病机制中新的干预靶点和治疗靶点。

Objective To elaborate whether the endoplasmic reticulum stress participateds in fatty degeneration induced by free fatty acids in vitro hepatic steatosis model, and potential impact of metformin on endoplasmic reticulum stress. Methods HepG2 cells were ex- posed to differrent types of culture media： control group（ conventional culture）, metformin group（2mmol/L metformin） , free fatty acid group （1 mmol/L fatty acids mixture） and the intervention group （1 mmol/L fatty acids mixture ＋ 2mmol/L metformin）. After incubation for 24h, survival rates and trigiyceridc level of HepG2 cells were determined. Reverse transcriptase polymerase chain reaction and Western blot were also performed to detect the expressions of glucose - regulated protein78 （ GRP78 ） , sterol response element - binding protein - 1 c （ SREBP1c）. Results The levels of triglyceride, mRNA and protein of GRP78 and SREBPlc significantly raised in the free fatty acids group compared with the other three groups. Then,when HepG2 cells with hepatic steatosis induced by free fatty acids were treated by met- formin, levels of triglyceride, mRNA and protein of GRP78 and SREBPlc were partially decreased but without significant differences. Conclusion Endoplasmic reticulum stress might participate in fatty degeneration induced by free fatty acids in vitro hepatic steatosis mod- el. Therefore, endoplasmic reticulum stress might serve as a novel target in the pathogenesis and therapeutic target for intervention for non - alcoholic fatty liver disease.