目的：研究α-硫辛酸（α-LA）对氯化镉（CdCl2）诱导HepG2细胞内产生rGSH水平、rGSH/GSSG比值及对GR酶活力的影响。方法实验采用的是HepG2细胞，CdCl2诱导细胞产生氧化损伤模型。实验分组如下：正常组、25μM CdCl2组、50μM α-LA组、（1μM、5μM、50μM）α-LA-CdCl2联合作用组。用含不同浓度梯度的α-LA培养液体外培养HepG2细胞8 h，再加入终浓度为25μM CdCl2继续培养16 h。采用DTNB法结合GSH和GSSG检测试剂盒，检测α-LA对CdCl2致HepG2细胞内rGSH水平和GR酶活力。结果与正常对照组相比较，经CdCl2诱导处理后，HepG2细胞内rGSH水平[（10.182±0.634） nM/μg蛋白]和rGSH/GSSG比值[（4.674±0.537）]降低（P＜0.01）、GR的酶活力[（0.072±0.005） U/mg protein]降低（P＜0.05）；不同浓度α-LA预处理后，随着浓度增加，细胞内rGSH水平[（11.519±0.492） nM/μg蛋白，（14.486±0.718） nM/μg蛋白，（17.802±0.372） nM/μg蛋白]和rGSH/GSSG比值[（5.068±0.978），（6.382±0.483），（7.823±0.284）]逐渐增高，GR酶活力[（0.080±0.031） U/mg protein，（0.087±0.061） U/mg protein，（0.092±0.015） U/mg protein]逐渐增加，并且中剂量（5μM）和高剂量（50μM）α-LA-CdCl2联合作用组细胞内rGSH水平与低剂量（1μM）α-LA-CdCl2联合作用组相比，差异有统计学意义（P＜0.05）。结论α-LA能有效拮抗CdCl2所诱导HepG2细胞内rGSH水平的降低，提高rGSH/GSSG比值和GR酶活力。%Objective To study the effect of α-lipoic acid on the production of glutathione in HepG2 cells induced by cadmium chloride.Methods We use HepG2 cells in the experiment, then induced by cadmium chloride to produce oxidative damage model. The whole cells were divided into normal group, cadmium chloride group andα-lipoic acid pre-treatment group. Cells were cultured with different concentrations ofα-lipoic acid (1 μM, 5 μM, 50 μM) for 8h,and exposed to a final concentration of 25 μM cadmium chloride for 16 h in the presence of α-lipoic acid. Then using DNTB method and GSH/GSSG assay kit to determine the rGSH contents, GSSG contents and GR activity of each group.Results Compared with the untreated group, the rGSH contents [(10.182±0.634) nM/μg protein] and the ratio of rGSH/GSSG [(4.674±0.537)] in HepG2 cells treated with 25 μM cadmium chloride were signiifcantly decreased(P<0.01), GR activity [(0.072±0.005) U/mg protein]were also decreased (P<0.05). After pre-treatment with different concentration of α-lipoic acid, the rGSH contents [(11.519±0.492) nM/μg protein ,(14.486±0.718) nM/μg protein, (17.802±0.372) nM/μg protein], the ratio of rGSH/GSSG [(5.068±0.978), (6.382±0.483), (7.823±0.284)]and GR activity [(0.080±0.031) U/mg protein, (0.087±0.061) U/mg protein, (0.092±0.015) U/mg protein]were significantly increased in a dose-dependent manner of HepG2 cells compared to 25 μM cadmium chloride.Conclusion α-lipoic acid could effectively prevent the decrease of the rGSH contents in HepG2 cells caused by cadmium chloride, increase of the ratio of rGSH/GSSG and the GR activity.
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