砷和二氯乙酰胺对HepG2细胞的联合暴露毒性效应  

Combined toxic effects of arsenic and dichloroacetamide in human HepG2 cells

作　　者：王智志 陈玲 张徐祥[1] 吴兵 Wang Zhizhi;Chen Ling;Zhang Xuxiang;Wu Bing(State Key Laboratory of Pollution Control and Resource Reuse,School of the Environmern,Nanjing University,Nanjing,210023,China)

机构地区：[1]污染控制与资源化研究国家重点实验室,南京大学环境学院,南京210023

出　　处：《南京大学学报（自然科学版）》2020年第5期719-728,共10页Journal of Nanjing University（Natural Science）

基　　金：江苏省科技支撑计划社会发展项目(BE2017709);国家重点研究发展计划(2016YF A0203103)。

摘　　要：饮用水中污染物间的联合毒性效应对评估饮用水健康风险具有重要意义,选择饮用水中备受关注的砷(arsenic,As)和消毒副产物二氯乙酰胺(dichloroacetamide,DCAcAm)为研究对象,分析人肝癌细胞HepG2暴露于As(0.375和0.75 mg·L^-1)和DCAcAm(0.1,1和10 mg·L^-1)24 h后的联合毒性效应.结果表明,DCAcAm单独暴露未降低HepG2细胞活力,但与As联合暴露时可增加As的细胞毒性.从化学检测和生物分子调控通路水平分析了联合毒性机制:DCAcAm提高了HepG2细胞对As的富集水平,并通过提高S-腺苷甲硫氨酸(S-adenosinemethionine,SAM)含量增加As的甲基化水平;DCAcAm还增强了As对氧化应激和DNA损伤等相关基因表达和代谢物水平的影响.上述研究结果表明,在进行饮用水中As毒性效应评估及其风险评价时,DCAcAm等消毒副产物的影响值得关注.Arsenic(As) and disinfection byproducts are of widespread concern in drinking water due to their high health risks.However,there is little report about the effect of co-exposure on their toxicological behaviors. In this paper,the dichloroacetamide(DCAcAm) was chosen as the representative disinfection byproduct. The human HepG2 cells were used to explore the combined toxicity of As(0.375 and 0.75 mg·L^-1) and DCAcAm(0.1,1 and 10 mg·L^-1). Experimental results showed that DCAcAm could significantly increase the cytotoxic effects of As with a certain dose-effect relationship.Underlying mechanisms of the combined toxicity were furtherly analyzed. First,the concentrations of total As and As species in the HepG2 cells were analyzed using ICP-MS and HPLC-ICP-MS,respectively. The concentrations of methyl donor,Sadenosine methionine(SAM),were determined by ELISA. The results showed that DCAcAm increased intracellular As accumulation in HepG2 cells,and increased the methylation level of As by increasing the SAM contents,which might be an important reason that DCAcAm increased As toxicity. Furthermore,the high-throughput PCR and NMR-based metabolomics studies were used to analyze the biological processes after combined exposure of As and DCAcAm. Results showed that DCAcAm enhanced the changes in expressions of genes related to intracellular oxidative stress and DNA damage,such as EGFR,ABCC2,APEX1 and ERCC2. Metabonomics analysis indicated that combined exposure of As and DCAcAm significantly altered the amino acid metabolism of HepG2 cells,decreased the levels of valine,leucine and isoleucine,and inhibited the process of aminoacyl-tRNA biosynthesis,which were similar with the effects of As alone exposure. The above results provide a mechanistic explanation for the synergistic toxic effects of As and DCAcAm. The results of this paper also show that during the evaluation of the toxic effects and health risks of As in drinking water,the influences of low concentration DCAcAm and other disinfection byproducts deserve our high

关 键 词：砷 二氯乙酰胺 联合毒性 基因表达 代谢组学 

分 类 号：X172[环境科学与工程—环境科学]