Effect of metformin on fatty liver and endoplasmic reticulum stress in high-fat-feeding-induced mice / 中华消化杂志

ABSTRACT

Objective To observe the effects of high-fat diet on liver steatosis and liver endoplasm reticulum stress in mice and to investigate the interventional effect of metfomin on them.Methods Forth-five male C57BL/J6 mice were divided into healthy control group,high-fat group and metformin group.High fat group and metformin group were fed with high-fat diet.Mice in metformin group were given metformin since the fourth week of high-fat feeding.After feeding for eight weeks,subperitoneal glucose tolerance test was performed in mice.After mice were sacrificed,liver triglyceride (TG) content and the expression of endoplasmic reticulum stress related factors at gene and protein levels were measured.One-way ANOVA was applied for analysis between groups.Results Compared with healthy control group,area under curve (AUC) of glucose tolerance and TG contents in liver tissues significantly increased in high-fat group [998±87 vs 1409±106,(10.05±0.29) μmol/g vs (27.11 ±4.76) μmol/g].Glucose tolerance and liver steatosis were improved in metformin group,AUC and TG of metformin group were significantly lower than those of high-fat group in metformin group [1178±90,(15.12±2.11) μmol/g,F=55.328,89.212,both P ＜0.01].Compared with healthy control group,the expression of glucose-regulated protein 94 (GRP94)at mRNA level significantly increased in high-fat group.Meanwhile,the expression of phosphorylated eukaryotic translation initiation factor 2α at protein level,which indicated endoplasmic reticulum stress,significantly increased.However,the expression of those endoplasmic reticulum stress markers at mRNA and protein level of metformin group were both lower than those of high fat group (F=84.002,137.321,both P＜0.05).Conclusions High fat diet caused liver steatosis in mice and accompanied by endoplasmic reticulum stress.Fatty liver was significantly improved by metformin treatment in high-fat-fed mice.The mechanism may be related with the improvement of endoplasmic reticulum stress by metformin.