苦荞清蛋白酶解物对高糖诱导的HepG2细胞胰岛素抵抗的保护作用

目的：建立胰岛素抵抗HepG2细胞模型，观察苦荞清蛋白酶解物（tartary buckwheat albumin hydrolysate，TBAH）对HepG2细胞胰岛素抵抗的影响。方法：采用碱性蛋白酶水解苦荞清蛋白制备TBAH，超滤法截留分子质量小于3 kDa的TBAH；利用高糖高胰岛素诱导HepG2细胞36 h建立胰岛素抵抗模型，以2.5、5、10 μg/mL的TBAH培养细胞24 h。观察TBAH对HepG2细胞葡萄糖代谢的影响；检测细胞氧化损伤指标（一氧化氮（nitric oxide，NO）、丙二醛（malondialdehyde，MDA）、乳酸脱氢酶（lactic dehydrogenase，LDH）、超氧化物歧化酶（superoxide dismutase，SOD）和活性氧（reactive oxygen species，ROS））水平；Western blot检测胰岛素受体底物1（insulin receptor substrate 1，IRS-1）/磷脂酰肌醇3-激酶（phosphatidylinositol 3-kinase，PI3K）/蛋白激酶B（protein kinase B，Akt）信号通路中相关蛋白表达情况。结果：与IR模型组相比，TBAH组葡萄糖消耗量显著增多（P＜0.05），且呈剂量依赖性，同时MDA、NO和ROS水平显著降低（P＜0.01，P＜0.05），SOD活力显著升高（P＜0.05），LDH活力显著下降（P＜0.05）；p-IRS-1蛋白表达水平显著降低（P＜0.05），磷酸化Akt、PI3K、葡萄糖转运蛋白4表达水平极显著上升（P＜0.01）。结论：TBAH通过抑制氧化应激改善胰岛素抵抗。

Protective Effect of Tartary Buckwheat Albumin Hydrolysate on High Glucose Induced Insulin Resistance in HepG2 Cells

Objective:To observe the effect of tartary buckwheat(FagoPyrum tataricum Gaertn.)albumin hydrolysate(TBAH)on insulin resistance in HepG2 cells.Methods:TBAH,prepared with alkaline protease,was ultrafiltrated to retain peptides with molecular mass less than 3 kDa.HepG2 cells were induced by high glucose and high insulin for 36 h to establish an insulin resistance model.Then,the cells were cultured with 2.5,5 and 10μg/mL TBAH for 24 h.The effect of TBAH on glucose metabolism in HepG2 cells was observed.The effects on oxidative damage indicators nitric oxide(NO),malondialdehyde(MDA),lactic dehydrogenase(LDH),superoxide dismutase(SOD),reactive oxygen species(ROS)and the insulin receptor substrate 1(IRS-1)/phosphatidylinositol 3-kinase(PI3K)/protein kinase B(Akt)signaling pathway in insulin-resistant HepG2 cells were also detected.Results:Compared with the insulin resistance model group,glucose consumption in the TBAH group was significantly increased(P<0.05)in a dose-dependent manner,while MDA,NO and ROS contents were significantly decreased(P<0.01,P<0.05);SOD activity was significantly increased(P<0.05),whereas LDH activity was significantly decreased(P<0.05);Phosphorylated IRS-1 protein expression level was decreased(P<0.05),whereas phosphorylated Akt,PI3K and glucose transporter 4 protein expression levels were significantly increased(P<0.01).Conclusion:TBAH can improve insulin resistance by inhibiting oxidative stress.