肿瘤坏死因子α诱导肝细胞胰岛素抵抗的机制

Mechanism of TNF-α-induced hepatic insulin resistance

目的探讨NADPH氧化酶(NOX)在肿瘤坏死因子α(TNF-α)诱导的肝细胞胰岛素抵抗(IR)中的作用。方法用TNF-α(4ng/ml)刺激HepG2细胞48h,建立IR细胞模型。蒽酮法测定细胞内糖原水平;DCFH-DA探针标记,流式细胞仪检测细胞内活性氧(ROS)水平;Western blot观察胰岛素受体底物1(IRS1)和p-IRS1水平。结果 TNF-α处理后,细胞内ROS水平增加,细胞内糖原含量显著降低。NOX的抑制剂DPI显著抑制TNF-α诱导的ROS产生,并且促进细胞内糖原的合成,同时逆转TNF-α对胰岛素信号通路的影响。结论 TNF-α通过激活NOX促进细胞内ROS水平增加,抑制NOX源性的ROS可以改善糖原合成。

Objective To demonstrate the key role of NADPH oxidase（NOX） derived ROS in TNF-α-induced hepatic insulin resistance.Methods Cultured HepG2 cells were treated for 48 h with 4ng/ml TNF-α to prepare a cellular model of insulin resistance.ROS level was determined by DCF-DA and FACS.The expression of IRS1 and p-IRS1 was analyzed by Western blot.Results In cultured HepG2 cells,TNF-α induced the decrease of glycogen and the increase of ROS.TNF-α down-regulated the level of IRS1 and stimulated its inhibited phosphorylation on Ser307.DPI can reverse the effect of TNF-α.Conclusions The effects of TNF-α on hepatic insulin resistance appear to be,at least in part,mediated by NOX-derived ROS.