目的 探索光甘草定改善肝细胞胰岛素抵抗（insulin resistance，IR）的作用和机制。方法 通过高胰岛素诱导人肝癌HepG2细胞建立IR模型，采用葡萄糖氧化酶法检测细胞的葡萄糖消耗量及生成；荧光标记法检测葡萄糖摄取量；蒽酮法检测糖原含量；ELISA检测葡萄糖代谢关键酶的活性；Western blotting检测磷脂酰肌醇3-激酶/蛋白激酶B（phosphatidylinositol3-kinase/protein kinase B，PI3K/Akt）、细胞外调节蛋白激酶/胰岛素受体底物-1（extracellular regulated protein kinase/insulinreceptor substrate-1，ERK/IRS-1）信号通路相关蛋白以及葡萄糖转运蛋白4（glucose transporter 4，GLUT4）的表达。采用分子对接技术研究光甘草定和ERK分子间的相互作用。结果 光甘草定显著增加IR-HepG2细胞的葡萄糖消耗和摄取（P＜0.05）；通过显著提高糖原合成酶（glycogen synthase，GS）、葡萄糖激酶（glucokinase，GCK）和丙酮酸激酶（pyruvate kinase，PK）活性（P＜0.05、0.01），促进IR-HepG2细胞的糖原合成和糖酵解；通过显著减弱磷酸烯醇丙酮酸羧激酶（phosphoenolpyruvate carboxykinase，PEPCK）和葡萄糖-6-磷酸酶（glucose-6-phosphatase，G6Pase）的活性（P＜0.05），抑制IR-HepG2细胞的糖异生。IR-HepG2细胞经光甘草定处理后，Akt、糖原合成酶激酶-3β（glycogen synthase kinase-3β，GSK-3β）和叉头框蛋白O1（forkhead boxing protein O1，FOXO1）的磷酸化水平得到显著恢复（P＜0.01），而这种作用被PI3K的抑制剂LY294002所逆转（P＜0.01）。同时，光甘草定显著促进GLUT4向质膜的易位（P＜0.01）。光甘草定显著降低IRHepG2细胞的ERK和IRS的磷酸化水平（P＜0.01），还可作为ERK的I1/2型抑制剂。结论 光甘草定通过抑制ERK/IRS-1通路，激活PI3K/Akt信号通路，修复IR-HepG2细胞的糖代谢紊乱，缓解IR症状。

Objective To explore the effect and mechanism of glabridin on ameliorating insulin resistance (IR) in hepatocytes. Methods IR model was established by high insulin-induced HepG2 cells. The cells we re evaluated for glucose consumption and production by glucose oxidase assay; The glucose consumption and Glucose uptake was detected by fluorescence method; The content of glycogen was detected by anthrone method; The activities of key enzymes in glucose metabolism was detected by ELISA; Western blotting was used to detect phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt), extracellular regulated protein kinase/insulin receptor substrate-1 (ERK/IRS-1) signaling pathway related protein and glucose transporter 4 (GLUT4) expressions. Molecular docking technique was used to study the interaction between glabridin and ERK molecules. Results Glabridin significantly increased the glucose consumption and uptake of IR-HepG2 cells (P<0.05); Glycogen synthesis and glycolysis of IR-HepG2 cells were promoted by significantly increasing the activities of glycogen synthase (GS), glucokinase (GCK) and pyruvate kinase (PK) (P<0.05, 0.01); The activities of phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) were significantly decreased (P<0.05), and gluconeogenesis of IR-HepG2 cells was inhibited. After IR-HepG2 cells were treated with glabridin, phosphorylation levels of Akt, glycogen synthase kinase-3β (GSK-3β) and forkhead boxing protein O1 (FOXO1) were significantly restored (P<0.01), and this effect was reversed by PI3K inhibitor LY294002 (P<0.01). Meanwhile, glabridin significantly promoted the translocation of GLUT4 to plasma membrane (P<0.01). Glabridin significantly reduced the phosphorylation levels of ERK and IRS in IR-HepG2 cells (P<0.01), and could be used as I^1/2 inhibitor of ERK. Conclusion Glabridin can repair the sugar metabolism disorder of IR-HepG2 cells and relieve IR symptoms by inhibiting ERK/IRS-1 pathway and activating PI3K/Akt signaling pathway.

R285.5

国家自然科学基金面上项目(31571800)