Ginsenoside Re reduces insulin resistance through activation of PPAR-γ pathway and inhibition of TNF-α production
Ginsenoside Re reduces insulin resistance through activation of PPAR-γ pathway and inhibition of TNF-α production
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DOI：
10.1016/j.jep.2013.03.057
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发表时间：
2013-05-20
影响因子：
5.4
通讯作者：
Zhang, Hai-long
中科院分区：
文献类型：
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作者：
Gao, Yang;Yang, Min-fei;Zhang, Hai-long
民族药理学相关性：人参是一种著名的传统中药，在亚洲已被用于治疗各种疾病超过四千年。人参皂苷是人参的有效成分，具有抗糖尿病活性，但其降血糖机制尚未完全阐明。本研究采用体外模型研究了抗肿瘤药物的作用机制，材料与方法：以3 T3-L1细胞为模型，研究抗肿瘤药物的分子作用机制。采用TG氧化酶法测定3 T3-L1脂肪细胞中TG含量，观察不同浓度的抗氧化剂对3 T3-L1脂肪细胞成脂能力的影响。通过测量H-3-2-脱氧-D-葡萄糖水平来定量在不存在或存在β-内酰胺Re的情况下由胰岛素刺激的3 T3-L1细胞中的葡萄糖摄取。使用各自的ELISA试剂盒测试释放到培养基中的细胞因子蛋白，包括脂联素和TNF-α。采用真实的实时RT-PCR检测PPAR-gamma及其相关基因ap 2、adiponectin、IRS-1、GLUT 4和TNF-α的表达变化。Western blot分析GLUT 4的易位情况。结果：人参皂苷Re可诱导3 T3-L1脂肪细胞成脂，其作用机制是通过增加TG、葡萄糖摄取、上调PPAR-gamma 2、IRS-1、ap 2和脂联素等基因表达。同时，Re也增加了脂联素的产生和释放。Re虽然对GLUT 4基因表达没有影响，但促进了GLUT 4蛋白向膜的转运。此外，Re抑制TNF-α的表达和释放。最后，Re对LPS、TNF-α和IFN-γ刺激的3 T3-L1细胞和LPS刺激的小鼠腹腔巨噬细胞中NO的产生没有显示出抑制作用。人参皂苷Re通过直接增加PPAR-gamma 2及其应答基因脂联素、IRS-1、ap 2、抑制TNF-α的产生并促进GLUT 4的易位以促进3 T3-L1脂肪细胞中葡萄糖的摄取和处置。(C)2013爱思唯尔爱尔兰有限公司版权所有。
Ethnopharmacological relevance: Panax ginseng is a well-known traditional Chinese medicine and has been used for treatment of various diseases for more than four thousand years in Asia. Ginseng saponins or ginsenosides, the active constituents are reported to possess antidiabetic activity, but their antihyperglycemic mechanisms are not fully elucidated. In the present study, the mechanisms of action of ginsenoside Re were investigated in vitro models.Materials and methods: 3T3-L1 cells were chosen as the model to investigate the molecular mechanisms of action of ginsenoside Re. Influence of ginsenoside Re on the adipogenesis was examined by determining TG levels in 3T3-L1 adipocytes by the method of TG oxidation enzyme. Glucose uptake in 3T3-L1 cells stimulated by insulin in the absence or presence of ginsenoside Re were quantified by measuring H-3-2-deoxy-D-glucose levels. Cytokine proteins released into the medium including adiponectin and TNF-alpha were tested using respective ELISA kits. In addition, real time RT-PCR was conducted to investigate the expression changes of PPAR-gamma and its responsive genes, ap2, adiponectin, IRS-1, GLUT4 and TNF-alpha. And western blot analysis was performed to determine the translocation of GLUT4. Finally, effects of ginsenoside Re on NO production in 3T3-L1 adipocytes and in macrophages were investigated through measurement of nitrite concentration by Griess reagent.Results: Ginsenoside Re induced adipogenesis of 3T3-L1 adipocytes by accumulating TG, increased glucose uptake and up-regulated PPAR-gamma 2, IRS-1, ap2 and adiponectin genes expressions. Meanwhile, Re also increased production and release of adiponectin. Although having no effects on GLUT4 gene expression, Re facilitated GLUT4 protein translocation to the membranes. In addition, Re inhibited the expression and release of TNF-alpha. Finally, Re did not show inhibitory effects on NO production both in 3T3-L1 cells stimulated by LPS, TNF-alpha and IFN-gamma and in LPS-stimulated mouse peritoneal macrophages.Conclusions: Ginsenoside Re exhibited the action of reducing insulin resistance through activation of PPAR-gamma pathway by directly increasing the expressions of PPAR-gamma 2 and its responsive genes, adiponectin, IRS-1, ap2, inhibiting TNF-alpha production and facilitating the translocation of GLUT4 to promote glucose uptake and disposal in 3T3-L1 adipocytes. (C) 2013 Elsevier Ireland Ltd. All rights reserved.