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

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），apoB100 mRNA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。

Effects of Exendin-4 on expressions of lipid metabolism related genes in HepG2 cells with insulin resistance

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.