人参皂甙Rb_1促进3T3-L1脂肪细胞分化并抑制脂解  

Ginsenoside Rb_1 facilitates adipocyte differentiation and inhibits lipolysis in 3T3-L1 adipocytes

作　　者：尚文斌[1] 杨颖[1] 姜博仁[1] 周丽斌[1] 唐金凤[1] 李凤英[1] 金华[1] 刘尚全[1] 陈名道[1] 

机构地区：[1]上海内分泌代谢病研究所上海交通大学医学院附属瑞金医院内分泌代谢病科上海市内分泌代谢病临床医学中心

出　　处：《中华内分泌代谢杂志》2007年第3期258-263,共6页Chinese Journal of Endocrinology and Metabolism

基　　金：上海市优秀青年医学人才培养基金(2004);上海市教委科研基金(05BZ28);上海联合利华研究发展基金(2004)

摘　　要：目的 观察人参皂甙Rb1（Rb1）对3T3-L1脂肪细胞分化和脂肪分解的作用，并探讨人参抗糖尿病的作用机制。方法 在3T3-L1脂肪细胞诱导分化过程中，分别加入不同浓度的Rb1作用6d，各组脂肪细胞分别进行油红O染色，甘油三酯（TG）含量、^3H-葡萄糖转运率检测，并用实时定量PCR和免疫印迹对脂肪细胞PPARγ2、CCAAT增强子结合蛋白（C／EBPα）、脂肪酸结合蛋白（ap2）和葡萄糖转运体（Glut）1、Glut4的mRNA和蛋白水平进行测定；运用表面等离子体共振技术（SPR）测定Rb1与PPARγ结合亲和力；在分化成熟的脂肪细胞加入Rb1孵育后，测定释放到上清液的甘油含量。结果Rb1能促进3T3-L1脂肪细胞的分化程度，并呈剂量依赖关系，10μmol／L浓度使细胞内TG含量增加约56％，同时PPARγ2和C／EBPα的mRNA和蛋白水平均显著升高，其下游基因ap2的mRNA水平也明显增加。分化过程中加入Rb1的脂肪细胞基础和胰岛素介导的葡萄糖转运率增加。Glut4的mRNA和蛋白水平均上升，而Glut1则未见显著变化；SPR检测结果显示Rb1具有PPARγ结合活性，提示Rb1是PPARγ的配体；在诱导分化成熟的脂肪细胞中，Rb1抑制基础脂肪分解，10μmol／L浓度使上清甘油含量下降约50％，但对异丙肾上腺素介导的脂解没有影响。结论 Rb1作为PPARγ的配体，通过上调PPARγ2,2C／EBPα的表达促进脂肪细胞的脂肪形成；增加基础和胰岛素刺激的葡萄糖利用；同时抑制基础脂解。以上结果表明人参和人参皂甙抗糖尿病的作用可能与促进脂肪细胞分化，增加胰岛素敏感性和抑制基础脂解有关。Objective To observe the effect of ginsenoside Rb1, the most abundant ginsenoside in ginseng root, on differentiation and lipolysis of 3T3-L1 cells and to explore its anti-diabetic mechanism. Methods 3T3-L1 preadipecytes were induced under standard differentiation process in the presence of 0. 1, 1,10, 100 μmol/L ginsenoside Rb, for 6 days. Oil red O staining, measurement of triglyceride contents and glucose uptake assay were performed. The expressions of mRNA and protein of PPARγ2, C/EBPα, ap2, glucose transporter （Glut）1, and Glut4 were analysed with quantitative real time-PCR and Western blot. The binding affinity of Rb1 to PPARγ-LBD was evaluated by Surface Plasmon Resonance （SPR）. Lipolysis of adipocytes was examined by the measurement of glycerol released from adipecytes treated with Rb1 for 1 h. Results Ginsenoside Rb, facilitated differentiation of 3T3-L1 preadipecytes in a dose-dependent manner. 10 μmol/L ginsenoside Rb, increased lipid accumulation by about 56%. Treatment of differentiating adipocytes with 10 μmol/L ginsenoside Rb, increased the expressions of PPARγ2 and C/EBPct mRNA and protein, as well as mRNA expression of ap2, one of their target genes. After treatment of differentiating adipocytes with Rb1, basal and insulin-mediated glucose transport augmented significantly accompanied by up-regulations of mRNA and protein level of Glut4, but not of Glutl. SPR showed Rb, could bind to PPARγ which suggested Rb, was a ligand of PPARγ. Ginsenoside Rb1 inhibited basal lipolysis in adipocytes in a dose-dependent manner. However, it did not affect isoproterenol-stimulated lipolysis. Conclusion As a PPARγ ligand, ginsenoside Rb, promotes adipogenesis, inhibites basal lipolysis and increases basal and insulin-mediated glucose transport in cultured adipocytes. Therefore, anti-diabetic and insulin-sensitizing activity of ginsenosides is, at least in part, involved in the enhancing effect on PPARγ2 and C/EBPα expressions, hence promoting adipogenesis and glucose uptake, and inhibiting lip

关 键 词：人参皂甙 脂肪细胞 分化 PPARγ CCAAT增强子结合蛋白 脂解作用 

分 类 号：R285.5[医药卫生—中药学]