Exendin-4对胰岛素抵抗人肝癌HepG2细胞脂代谢相关因子基因表达的影响

摘要

目的:探讨Exendin-4 (Ex-4)对胰岛素抵抗(IR)人肝癌HepG2细胞脂代谢相关因子表达的影响,阐明Ex-4改善IR的作用.方法:选取处于对数生长期的人肝癌HepG2细胞,采用高浓度胰岛素诱导HepG2细胞制备IR模型(HepG2-IR细胞),再将其分为对照组(不含胰岛素的HepG2细胞)、IR组(IR模型,即HepG2-IR细胞)和Ex-4组(IR模型中加入10 nmol·L-1 Ex-4).采用葡萄糖氧化酶法(GOD-POD)检测细胞中葡萄糖消耗量,采用油红O染色观察细胞形态及胞内脂滴形成情况,应用甘油三酯(TG)试剂盒检测细胞中TG水平,采用荧光定量PCR (qRT-PCR)法检测细胞中乙酰辅酶A羧化酶(ACC)、脂肪酸合成酶(FAS)、固醇调节元件结合蛋白1c (SREBP-1c)和载脂蛋白B100 (apoB100)等脂代谢相关因子mRNA表达水平.结果:HepG2细胞建立IR模型后,与对照组比较,IR组HepG2-IR细胞葡萄糖消耗量明显降低(P＜0.01);与IR组比较,Ex-4组HepG2-IR细胞葡萄糖消耗量明显增加(P＜0.05).油红O染色法,与对照组比较,IR组细胞含脂率明显升高(P＜0.05);与IR组比较,Ex-4组细胞中含脂率明显降低(P＜0.05).与对照组比较,IR组细胞中TG水平明显升高(P＜0.01);与IR组比较,Ex-4组细胞中TG水平明显降低(P＜0.05).qRT-PCR检测,与对照组比较,IR组细胞中ACC、FAS和SREBP-1c mRNA表达水平明显升高(P＜0.01),apoB100mRNA表达水平明显降低(P＜0.05);与IR组比较,Ex-4组细胞中ACC、FAS和SREBP-1c mRNA表达水平降低(P＜0.05),apoB100mRNA表达水平升高(P＜0.01).结论:Ex-4可通过调节人肝癌HepG2细胞脂类代谢相关因子的表达进而改善IR.%Objective:To investigate the effects of Exendin-4 (Ex-4) on the expressions of lipid metabolism related genes in the human liver cancer HepG2 cells with insulin resistance (IR),and to elucidate the effect of Ex-4in improvement of IR.Methods:The HepG2 cells in logarithmic growth phase were induced into IR model with high concentration of insulin,then divided into control group (HepG2 cells),IR group (HepG2 cells were treated with insulin,HepG2-IR cells),and Ex-4 group (HepG2-IR cells were treated with Ex-4).Glucose oxidase (GOD-POD)kit was used to detect the consumption of glucose.The cell morphology and intracellular lipid drip formation were observed by Oil red O staining.The triglyceride (TG) level in cells was detected by kit;qRT-PCR was used to detect the mRNA expression levels of acetyl-CoA carboxylase (ACC),fatty acid synthase (FAS),sterol regulatory element-binding protein-1c (SREBP-1c) and apolipoprotein B100 (apoB100).Results:Compared with control group (HepG2 cells),the glucose consumption in the HepG2-IR cells in IR group was significantly decreased (P＜0.01).Compared with IR group,the glucose consumption in the HepG2-IR cells in Ex-4 group was increased (P＜0.05).The Oil O red staining results showed that compared with control group,the fat percentage in the HepG2-IR cells in IR group was increased (P＜0.05);compared with IR group,the fat percentage in Ex-4 group was decreased (P＜0.05).Compared with control group,the level of TG in the cells in IR group was significantly increased (P＜0.01);compared with IR group,the level of TG in the cells in Ex-4 group was significantly decreased (P＜0.05).The qT-PCR results showed that compared with control group,the expression levels of ACC FAS and SREBP-1cmRNA in the cells in IR group were increased (P＜0.01),and the expression level of apoB100 mRNA was decreased (P＜0.05);compared with IR group,the expression levels of ACC,FAS and SREBP-1c mRNA in the cells in Ex-4 group were decreased (P＜0.05),and the expression level of apoB100 mRNA was increased (P＜0.01).Conclusion:Ex-4 can regulate the expressions of lipid metabolism related genes in the HepG2 cells and improve IR.