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目的观察表没食子儿茶素没食子酸酯(EGCG)对肿瘤坏死因子-α(TNF-α)诱导的大鼠肌细胞胰岛素抵抗的影响。方法分化好的L6肌细胞分为7组:A组(对照)、B组(100nmol/L胰岛素)、C组(10μg/LTNF-α)、D组(100nmol/L胰岛素+10μg/LTNF-α)、E组(胰岛素+TNF-α+10μmol/LEGCG)、F组(胰岛素+TNF-α+20μmol/LEGCG)、G组(胰岛素+TNF-α+40μmol/LEGCG),继续培养24 h。实验结束后采用葡萄糖转运实验检测胰岛素刺激下L6细胞对葡萄糖的利用情况,Western blot检测细胞胰岛素受体底物-1(IRS-1)和AMP激活的蛋白激酶(AMPK)的蛋白表达水平。结果与100 nmol/L胰岛素组比较,10μg/L TNF-α作用24h后胰岛素刺激下细胞内葡萄糖转运量明显减少(P<0.05),而EGCG作用后明显改善TNF-α的抑制作用(P<0.05),并呈剂量反应关系。Western blot结果显示,与胰岛素组相比,TNF-α增高IRS-1的Ser307磷酸化表并降低AMPK的磷酸化水平,而EGCG作用后减少IRS-1的Ser307磷酸化表达同时升高AMPK的磷酸化水平。结论10μg/L TNF-α作用24 h能诱导L6肌细胞的胰岛素抵抗,而EGCG能改善这种胰岛素抵抗,可能是通过减少IRS-1的Ser307磷酸化进而增加AMPK的磷酸化表达来实现的。
Objective To observe the effect of epigallocatechin gallate (EGCG) on the insulin resistance of rat myocytes induced by tumor necrosis factor-α (TNF-α). Methods The differentiated L6 myocytes were divided into 7 groups: group A (control), group B (100nmol / L insulin), group C (10μg / LTNF-α) and group D (100nmol / L insulin + 10μg / , Group E (insulin + TNF-α + 10μmol / LEGCG), group F (insulin + TNF-α + 20μmol / LEGCG) and group G (insulin + TNF-α + 40μmol / LEGCG) Glucose transport was used to test glucose utilization in L6 cells stimulated by insulin. Western blot was used to detect the protein expression of insulin receptor substrate-1 (IRS-1) and AMP-activated protein kinase (AMPK). Results Compared with the 100 nmol / L insulin group, the intracellular glucose transport was significantly decreased (P <0.05) after treated with 10 μg / L TNF-α for 24 h, while the inhibitory effect of EGCG on TNF-α significantly decreased (P < 0.05), and showed a dose-response relationship. Western blot results showed that compared with the insulin group, TNF-α increased the Ser307 phosphorylation of IRS-1 and decreased the phosphorylation of AMPK, while the effect of EGCG decreased Ser307 phosphorylation of IRS-1 while increasing the phosphorylation of AMPK Level CONCLUSION: Twenty-four hours after treatment with 10μg / L TNF-α, insulin resistance of L6 myocytes can be induced. However, EGCG can improve this insulin resistance by decreasing phosphorylation of Ser307 and increasing phosphorylation of AMPK in IRS-1 cells.