姜黄素诱导Nrf2核转位对氧化应激诱导人肝细胞胰岛素抵抗的影响

摘要

目的:研究姜黄素诱导转录因子NF-E2相关因子2(NF-E2-related factor 2,Nrf2)核转位对氧化应激诱导人肝细胞L02胰岛素抵抗的影响.方法:用15μM和30μM姜黄素干预L02肝细胞6h和12h,Western blot检测Nrf2核转位水平;将肝细胞分为对照组、模型组、干预组,对照组用RPMI1640正常培养,模型组用100U/L葡萄糖氧化酶(GO)干预2 h,干预组用15 μ M和30μ M姜黄素分别干预12 h后给予100 U/L GO干预2 h,各细胞均给予100 nM胰岛素干预30 min.流式细胞术检测细胞内活性氧簇(ROS),用荧光强度(FI)来表示ROS水平.分光光度法检测检测细胞MDA、GSH,葡萄糖氧化酶-过氧化物酶法检测细胞培养液中葡萄糖的水平,Western blot检测胰岛素受体底物-1(IRS-1)磷酸化水平.结果:①姜黄素明显诱导Nrf2核转位.②模型组FI、MDA水平较对照组显著升高(P＜0.01),干预组FI、MDA水平均较模型组显著降低(P＜0.01),姜黄素15 μ M组FI、MDA水平高于30 μ M组(P＜0.01).模型组GSH水平较对照组显著降低(P＜0.01),干预组GSH水平较模型组显著升高(P＜0.01),姜黄素15μ M组FI、MDA水平高于30 μ M组(P＜0.01).③模型组上清液葡萄糖浓度显著高于对照组(P＜0.01),干预组上清液葡萄糖浓度显著低于模型组(P＜0.01),姜黄素15 μ M组上清液葡萄糖浓度高于30 μ M组(P＜0.01).模型组IRS-1磷酸化水平较对照组降低,干预组IRS-1磷酸化水平均较模型组增高,姜黄素30μM组IRS-1磷酸化水平高于15 μ M组.结论:姜黄素通过诱导Nrf2核转位,降低细胞内氧化应激水平,进而逆转氧化应激诱导的胰岛素抵抗.%Objective: To investigate the effect of nuclear factor E2-related factor 2 (Nrf2) translocation induced by curcumine on oxidative stress mediated insulin resistance (IR) in human LO2 hepatocyte. Methods: The Nrf2 in nuclear fractions was assayed by westem blot analysis. The intercellular ROS level was analyzed on a flow cytometer by dihydroethidium and was indicated with fluorescence intensity (FI). The levels of MDA and GSH were measured by spectrophotometric method. The glucose in culture medium was detected by the glucose oxidizes peroxides method. The levels of IRS-1/p-IRS-1 were measured by western blot. Results: ①The levels of Nrf2 in the nucleus increased markedly in hepatocytes treated by curcumine compared with that of the cells in control group. At the same time point, nuclear Nrf2 was higher in cells treated by 30 μ M curcumine than that in cells treated by 15 lμ M curcumine. Treated by the same curcumine concentration, the nuclear Nrf2 level was higher in cells treated for 12 h than that in cells treated for 6 h. ②The levels of FI and MDA increased significantly in model compared with that in the control group (P＜0.01), both of which were significantly abrogated in curcumine group (P＜0.01). However, the levels of FI and MDA in 15 μ M curcumine group were significantly higher than those in 15 μ M curcumine group (P＜0.01). Compared with control group, the level of GSH decreased significantly in model group(P＜0,01), the decreased GSH levels in model group were significantly abrogated in curcumine group (P＜0.01), and the GSH levels in 15 μ M curcumine group were significantly higher than that in 30 μ M curcumine group (P＜0.01). ③The glucose in culture medium increased significantly in model group compared with that in control group (P＜0.01), the increased level was significantly abrogated in curcumine group (P＜0.01). However, the level in 15 μ M curcumine group were significantly lower than that in 30 μ M curcumine group (P＜0.01). IRS-1 phosphorylation in model group decreased compared with that in control group and IRS-1 phosphorylation in curcumine group increased in comparison with model group. The level of IRS-1 phosphorylation in 15 μ M curcumine group was markedly lower than that in 30 μ M curcumine group. Conclusion: Curcumine could induce Nrt2 nuclear translocation in cultured hepatocyte L02 and decrease intercellular ROS, subsequently improve oxidative stress-mediated IR.