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目的研究乙酰左旋肉碱(ALC)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6组,分别为对照组、100nmol/L胰岛素组、100nmol/L胰岛素+10ng/ml TNF-α组、胰岛素+TNF-α+三个不同浓度ALC组(浓度分别为0.1、0.3、0.6mmol/L),继续培养24h。实验结束后分别用葡萄糖消耗实验、葡萄糖转运实验检测胰岛素刺激下L6细胞对葡萄糖的消耗和利用情况,Western blot检测细胞胰岛素受体底物-1(insulin receptor substrate-1,IRS-1)的蛋白表达水平。结果与100nmol/L胰岛素组比较,10ng/ml TNF-α作用24h后胰岛素刺激下细胞上清液中葡萄糖的残存量显著增加和细胞内葡萄糖转运量明显减少(P<0.05),而ALC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磷酸化表达,而ALC作用后减少IRS-1的Ser307磷酸化表达。结论10ng/ml TNF-α作用24h能诱导L6肌细胞的胰岛素抵抗,而ALC能改善这种胰岛素抵抗,可能是通过减少IRS-1的Ser307磷酸化表达来实现的。
Objective To investigate the effect of acetyl leucocarnitine (ALC) on the insulin resistance of rat myocytes induced by tumor necrosis factor α (TNF-α). Methods The differentiated L6 myocytes were divided into 6 groups: control group, 100 nmol / L insulin group, 100 nmol / L insulin + 10 ng / ml TNF-α group and insulin + TNF- Respectively 0.1,0.3,0.6 mmol / L), continue to train for 24h. At the end of the experiment, glucose consumption and glucose depletion were measured in glucose-depleted and glucose-depleted L6 cells respectively. Western blot was used to detect the protein expression of insulin receptor substrate-1 (IRS-1) The expression level. Results Compared with the 100 nmol / L insulin group, the residual glucose in the supernatant of the cells stimulated by 10 ng / ml TNF-α increased significantly and the intracellular glucose transport decreased significantly (P <0.05) Significantly improve the inhibition of TNF-α (P <0.05), and dose-response relationship. Western blot results showed that compared with the insulin group, TNF-α increased Ser307 phosphorylation of IRS-1, while ALC decreased the phosphorylation of Ser307 of IRS-1. Conclusion The effect of 10ng / ml TNF-α for 24 h can induce insulin resistance in L6 myocytes. However, ALC can improve the insulin resistance by reducing the phosphorylation of Ser307 in IRS-1.