GLP-1对3T3-L1前脂肪细胞分化过程中FABP-4、CPT-1A水平的影响

Effect of glucagon-like peptide-1 on the levels of FABP-4 and CPT-1A during the process of 3T3-L1 preadipocyte differentiation

目的探讨胰高糖素肽-1(GLP-1)对3T3-L1前脂肪细胞分化过程中游离脂肪酸结合蛋白4(FABP-4)、肉碱脂酰转移酶1A(CPT-1A)表达水平的影响。方法采用传统"鸡尾酒"法诱导3T3-L1前脂肪细胞分化,并在分化过程中加入1×10-8mol/L GLP-1进行干预。在诱导分化的第6、8天,用油红O染色检测细胞内脂质聚集,RT-PCR及Western blotting法检测FABP-4、CPT-1A的mRNA及蛋白水平。结果①在诱导分化第6天,大约40%的细胞出现脂滴聚集,第8天时大约80%的细胞已分化成熟;②油红O染色结果显示,与对照组相比,GLP-1组脂质总量在分化第6天略有增加,在分化第8天轻度下降(P>0.05);③RT-PCR结果显示,GLP-1组FABP-4的mRNA水平在分化第6、8天都明显增加;CPT1-A的mRNA水平在分化第8天增加明显(P<0.05);④Western blotting结果显示,GLP-1显著增加了FABP-4的蛋白表达(P<0.05)。对照组CPT-1A的蛋白水平在分化第6、8天无显著变化;而GLP-1组CPT-1A蛋白水平显著增加,尤其在分化第8天,与对照组相比增加了3.57倍(P<0.01)。结论在3T3-L1前脂肪细胞分化过程中,GLP-1显著促进了FABP-4和CPT-1A的mRNA及蛋白水平,提示GLP-1同时促进脂肪细胞对游离脂肪酸的吸收及分解,能有效改善游离脂肪酸介导的胰岛素抵抗。

Objective To examine the effect of glucagon-like peptide-I （ GLP-1 ） on the levels of fatty acid binding protein 4 （FABP-4） and carnitine palmitoyltransferase 1A （CPT-1A） during 3T3-L1 preadipocyte differentiation process. Methods In this paper, the traditional ＂Cocktail method＂ was adopted to induce the 3T3-L1 preadipocyte differentiation and 1 ×10 -8 mol/L GLP-1 was added to the medium. At the 6th day and the 8th day of differentiation, Oil Red O staining was used to examine the lipid accumulation; RT-PCR and Western blotting were employed to test the levels of FABP-4 and Ct＇T-1A. Results 0）It is found that about forty percent of the cells appeared lipid droplets at the6th day; about eighty percent of the cells had differentiated to mature adipocytes at the 8th day. （1）The results of Oil Red O staining showed that the lipid accumulations in GLP-1 group were slightly increased at the 6th day while modestly decreased at the 8th day （ both P 〉 0.05 ）, as compared to the control group. （1）RT-PCR results indicated that the mRNA level of FABP-4 in GLP-1 group was significantly increased at the 6th day and the 8th day. And the mRNA lev- el of CPT-1A was also enhanced at the 8th day （P 〈 0.05 ）. （2） Western blotting results showed that the protein expres- sion of FABP-4 in GLP-1 group was improved markedly at the 6th day and the 8th day （ P 〈 0.05 ）. The protein level of CPT-1A in control group was not changed significantly. While it was greatly increased in the cells treated with GLP- 1, which was increased 3.57 times as compared to control group at the 8th day （ P 〈 0.01 ）. Conclusion GLP-1 can significantly promote the expressions of FABP-4 and CPT-1A during the process of 3T3-L1 preadipocyte differentiation, which indicates that GLP-1 can simultaneously promote the fatty acid absorption and decomposition and it has played an important role in improving the free fatty aicd induced insulin resistance.