Ginsenoside Rb_1 facilitates adipocyte differentiation and inhibits lipolysis in 3T3-L1 adipocytes / 中华内分泌代谢杂志

ABSTRACT

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 preadipoeytes were induced under standard differentiation process in the presence of 0.1,1,10,100?mol/L ginsenoside Rb_1 for 6 days.Oil red O staining,measurement of triglyceride contents and glucose uptake assay were performed.The expressions of mRNA and protein of PPAR?2,C/EBP?,ap2,glucose transporter (Glut) 1,and Glut4 were analysed with quantitative real time-PCR and Western blot.The binding affinity of Rb_1 to PPAR?-LBD was evaluated by Surface Plasmon Resonance (SPR).Lipolysis of adipocytes was examined by the measurement of glycerol released from adipoeytes treated with Rb_1 for 1 h.Results Ginsenoside Rb_1 facilitated differentiation of 3T3-L1 preadipoeytes in a dose-depondent manner.10?mol/L ginsenoside Rb_1 increased lipid accumulation by about 56%.Treatment of differentiating adipocytes with 10?mol/L ginsenoside Rb_1 increased the expressions of PPAR?2 and C/EBP?mRNA and protein,as well as mRNA expression of ap2,one of their target genes.After treatment of differentiating adipoeytes with Rb_1,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_1 could bind to PPAR?which suggested Rb_1 was a ligand of PPAR?.Ginsenoside Rb_1 inhibited basal lipolysis in adipoeytos in a dose-dependent manner.However,it did not affect isoproterenol-stimulated lipolysis.Conclusion As a PPAR?ligand,ginsenoside Rb_1 promotes adipogenesis,inhibitas basal lipolysis and inereasos basal and insulin-mediated glucose transport in cultured adipoeytes.Therefore,anti-diabetic and insulin-sensitizing activity of ginsenosides is,at least in part,involved in the enhancing effect on PPAR?2 and C/EBP?expressions,hence promoting adipogenesis and glucose uptake,and inhibiting lipolysis in adipocytes.