芦荟多糖对D-半乳糖致HepG2细胞氧化损伤的保护作用

Protective Effect of Aloe Polysaccharide on Oxidative Stress Injury of HepG2 Cells Induced by D-galactose

目的:探讨芦荟多糖对HepG2细胞氧化损伤的保护作用,分析其体外抗氧化能力。方法:以HepG2细胞为研究对象,建立D-半乳糖诱导细胞氧化损伤模型,以不同浓度芦荟多糖进行预保护处理。采用细胞增殖与毒性检测试剂盒测定HepG2细胞存活率,生物化学法检测细胞超氧化物歧化酶、过氧化氢酶、谷胱甘肽过氧化物酶活力,酶联免疫吸附法测定细胞总抗氧化能力及丙二醛(malondialdehyde,MDA)含量,实时荧光定量PCR检测细胞Keap1、Nrf2、NQO1和HO-1基因表达水平。结果:与D-半乳糖模型组比较,25、50、100μg/mL的芦荟多糖预保护处理能不同程度地提高HepG2细胞存活率;芦荟多糖能显著增强细胞中抗氧化酶的活性,降低细胞MDA的生成量(P<0.05),且作用效果与芦荟多糖浓度成正比;细胞中Keap1基因表达显著降低,Nrf2、NQO1、HO-1 mRNA表达显著提高(P<0.05)。结论:芦荟多糖可以减轻HepG2细胞的氧化应激损伤,激活Nrf2表达并抑制其泛素化降解,提高下游NQO1、HO-1的转录水平,增强细胞抗氧化酶系活性并调控细胞氧化还原系统,以达到减轻细胞氧化损伤程度、提高细胞抗氧化应激损伤的效果。

Objective:To investigate the protective effect of aloe polysaccharide on oxidative damage in HepG2 cells,and analyze its antioxidant capacity in vitro.Methods:HepG2 cells were used as the study target,to establish D-galactose-induced cell oxidation damage model and pre-protected with different concentrations of aloe polysaccharide.Cell Counting Kit-8 was used to determine the survival rate of HepG2 cells,biochemical assays were performed to detect the cellular superoxide dismutase,catalase and glutathione peroxidase activities,enzyme-linked immunosorbent assay was used to determine the total antioxidant capacity and malondialdehyde content.Quantitative real-time PCR was used to detect the cellular Keap1,Nrf2,NQO1 and HO-1 gene expression levels.Results:Compared with the D-galactose model group,the pre-protection with 25,50,100μg/mL of aloe polysaccharide increased the survival rate of HepG2 cells to different degrees.Aloe polysaccharide significantly enhanced the activity of antioxidant enzymes in cells and reduced the production of malondialdehyde in cells(P<0.05),and the effect was proportional to the concentration of aloe polysaccharide.The expression of Keap1 in cells was significantly reduced,and the expression of Nrf2,NQO1 and HO-1 in cells was significantly increased(P<0.05).Conclusion:Aloe polysaccharide can reduce oxidative stress damage in HepG2 cells,activate Nrf2 expression and inhibit its ubiquitination degradation,increase the transcription level of downstream NQO1 and HO-1,enhance the activity of cellular antioxidant enzymes and regulate the cellular redox system,to reduce the degree of oxidative damage and improve the effectiveness of cellular resistance to oxidative stress damage.