果糖通过激活Akt信号通路促进3T3-L1细胞的脂肪分化

Fructose promotes differentiation of 3T3-L1 preadipocytes by activating Akt signaling pathway

目的:研究果糖(fructose)对3T3-L1前脂肪细胞分化过程的影响及其作用机制。方法:对体外培养的3T3-L1前脂肪细胞给予鸡尾酒法诱导脂肪分化,并使用1 g/L的果糖进行诱导干预。油红O染色法定量分析细胞内的脂质含量;RT-qPCR法检测脂肪分化过程中脂滴包被蛋白2(Plin2)、CCAAT/增强子结合蛋白(C/EBP)α和C/EBPβ的mRNA表达水平;Western blot检测脂肪分化标志蛋白过氧化物酶体增殖物激活受体γ(PPARγ)和脂肪细胞蛋白2(αP2)的蛋白表达水平。结果:与单纯用分化培养基(DM)的对照组相比,实验(DM+fructose)组的脂肪细胞体积及胞质内脂滴积累量显著增加,脂肪分化标志蛋白PPARγ和aP2的表达水平显著上调(P<0.01),Plin2、C/EBPα和C/EBPβ的mRNA表达水平亦显著上调(P<0.05)。此外,加入果糖之后Akt信号通路中的关键分子Akt的磷酸化水平显著增加(P<0.01),加入Akt特异性阻断剂之后,PPARγ和aP2的表达水平显著下调。结论:果糖能够促进3T3-L1细胞的脂肪分化,可能是通过激活Akt信号通路实现的。

AIM: To study the effect of fructose on the differentiation of 3 T3-L1 preadipocytes and the specific mechanism. METHODS: 3 T3-L1 preadipocytes were cultured in vitro, induced to differentiate by cocktail method and treated with fructose at 1 g/L. The intracellular lipid content was identified and quantified by oil red O staining. The mRNA expression of perilipin-2(Plin2), CCAAT/enhancer binding protein(C/EBP) α and C/EBPβ was detected by RT-qPCR. The protein expression of peroxisome proliferator-activated receptor γ(PPARγ) and adipocyte protein 2(aP2) was determined by Western blot. RESULTS: The volume of differentiated adipocytes and the accumulation of cytoplasmic lipid droplets in the 3 T3-L1 cells with fructose intervention were increased compared with control group(P<0.05). Compared with control group, the expression levels of the marker proteins PPARγ and aP2 were up-regulated(P<0.01). The mRNA expression levels of Plin2, C/EBPα and C/EBPβ were up-regulated(P<0.05). In addition, the phosphorylation level of the key molecule Akt in the Akt signaling pathway was significantly increased(P<0.01) after the addition of fructose. After the addition of Akt blocker, the expression levels of PPARγ and aP2 were decreased. CONCLUSION: Fructose promotes the adipose differentiation of 3 T3-L1 cells possibly by activating the Akt signaling pathway.