Exendin-4对脂肪细胞分化及糖脂代谢相关基因mRNA表达的影响

目的探讨Exendin-4对3T3-L1前脂肪细胞的分化及糖脂代谢相关基因mRNA表达的影响。方法体外培养3T3-L1前脂肪细胞，在脂肪细胞分化成熟过程中的不同时期分别用Exendin-4等干预，采用油红O染色，观察脂肪细胞分化及脂质积聚情况；采用荧光定量PCR检测脂肪细胞糖脂代谢标志基因GLUT-4、PPARγ、HSLmRNA表达水平。酶法测定脂肪细胞的甘油三酯含量。结果分化成熟的脂肪细胞经油红O染色可见细胞质内大片脂滴呈亮红色，而未分化细胞不被油红O染色。在脂肪细胞分化第0天和第6天用Exendin-4干预，脂肪细胞内TG的含量较空白组增加（P〈0．01），GLUT-4、HSL、PPARγ mRNA的表达上调（P〈0．01）；在脂肪细胞分化的第12天干预，Exendin-4对肪细胞分化及相关基因mRNA的表达与空白组无明显差异。结论Exendin-4促进脂肪细胞的分化并上调糖脂代谢相关基因GLUT-4、PPARγ、HSL mRNA表达，可能为Exendin-4抗糖尿病的部分作用机制。

Effects of exendin-4 treatment on differentiation of 3T3-L1 preadipocyte and on mRNA expressions of glucose and lipid metabolic marker genes

Objective To investigate the effect of exendin-4 on differentiation of 3T3-L1 preadipocytes and mRNA expression of glucose and lipid metabolic marker genes. Methods 3T3-L1 preadipocytes were cultured in vitro and diferentiated into the matured adipocytes. Cell diferentiation and lipid accumulation were determined by oil red O staining. Glucose and lipid metabolism marker genes （GluT-4, PPAR-γ and HSL） mRNA expression were evaluated by quantitative real-time PCR. The triglyceride contents of isopropanol extracts prepared from 3T3-L1 preadipocytes were quantitated with an acetylacetone-based colorimetrie kit. Results Mature adipocytes showed large lipid droplets within cytoplasm stained by oil red O. Preadipocyte differentiation were promoted, TG content and the mRNA expressions of GluT-4, HSL and PPAR-γ were increased （P%0.01） when 3T3-L1 preadipocytes were treated with exendin-4 at day 0 and day 6. Compared with control group, the effects of exendin 4 on adipocytes differentiation and mRNA expression of these genes had no significant difference when 3T3-L1 preadipocytes were treated at day 12. Conclusion Exendin-4 promotes the preadipocytes differentiation, increases glucose and lipid metabolism marker genes mRNA expression, which may be some new mechanisms of exendin-4 anti-diabetes action.