Abstract:This study investigated the effect of ethanol extract of Ganoderma lucidum on insulin resistance in 3T3-L1 adipocytes induced by dexamethasone.An adipocyte insulin resistance model induced by dexamethasone was adopted.Cells were divided into a normal group，a model group，a G.lucidum ethanol extract group，and a metformin（positive control）group.The effect of G.lucidum ethanol extract on insulin resistance was analyzed through detecting the glucose consumption and triglyceride content of each group.Compared with the normal group，1 μmol/L dexamethasone significantly reduced glucose consumption of 3T3-L1 adipocytes after treatment for 72 h（P＜0.05），and the state of insulin resistance was stable within 24 h，indicating that the adipocyte insulin resistance model was successfully established.G.lucidum ethanol extract with 10，50 mg/L，and 100 mg/L had no significant effect on cell viability.G.lucidum ethanol extract significantly increased glucose consumption and intracellular triglyceride content of adipocytes in a dose-dependent manner after treatment for 24 h.At the same time，the protein expressions of insulin receptor substrate（IRS1），glucose transporter 4（GLUT4），phosphoinositide 3 kinase p110 （PI3K p110），PI3K p85，phosphor-kinase-protein kinase B （p-AKT），and phosphorylated glycogen synthase kinase-3β（p-GSK3β）was significantly increased after G.lucidum ethanol extract treatment.The results showed that G.lucidum ethanol extract ameliorated dexamethasone-induced insulin resistance in adipocytes through the expression of IRS1/PI3K/AKT signaling pathway.