2,2',4,4'-四溴联苯醚对赤子爱胜蚓的抗氧化酶、代谢酶及其基因表达的影响

Effects of 2,2',4,4'-tetrabromodiphenyl ether on antioxidant and metabolic enzymes and gene expression levels of earthworms (Eisenia fetida)

多溴联苯醚(PBDEs)是广泛存在于环境中的一种新型持久性有机污染物.四溴联苯醚同分异构体中的BDE-47是多溴联苯醚中最重要的单体之一.试验采用人工土壤培养法,通过亚急性试验,研究了在不同暴露时间阶段下,不同BDE-47剂量对赤子爱胜蚓(Eisenia fetida)抗氧化酶(过氧化氢酶CAT)、代谢酶(谷胱甘肽转移酶GST)以及二者基因表达的影响.结果表明,在暴露14 d和28 d时,CAT活性被诱导上升并且差异显著;GST活性变化差异不显著;CAT基因表达水平在第14 d时呈现抑制效应,在后续的第28 d和第42 d基因表达水平上调;GST基因表达水平整体呈现诱导效应,并且差异显著,随着暴露时间的增加,低毒处理组(10、50 mg·kg-1)的基因表达水平逐渐下调至低于对照组的水平,高毒处理组(100、200 mg·kg-1)的基因表达量仍高于对照组水平;在BDE-47的暴露试验中,CAT与GST活性及其基因表达水平两项指标对低毒处理组较高毒处理组更为敏感.

PBDEs are recognized as persistent organic pollutants and widely distributed in environment.2,2',4,4'-tetrabromodiphenyl ether(BDE-47)is one of the main monomers of PBDEs.In this paper,an artificial soil method was applied to study the effects of BDE-47 on enzyme activities of antioxidant enzyme(CAT) and metabolic enzyme(GST) and their gene expression levels of earthworms(Eisenia fetida).Results showed that the changing tendency of CAT activity presented a pattern of significant induction efficiency to control levels with the increase of BDE-47 exposure time,while the change of GST activity was insignificant.In general,BDE-47 mainly induced the gene expression of GST all the time significantly and greatly inhibited the gene expression of CAT on the 14 thday.With increasing exposure time,the gene expression levels of GST recovered to the level as the control group at low concentrations(10 and 50 mg·kg-1) and remained the status of induction at high concentrations(100 and 200 mg·kg-1).The biological indicators of activities of antioxidant enzyme(CAT) and metabolic enzyme(GST) and their gene expressions at low BDE-47 concentrations were more sensitive than that at high BDE-47 concentrations.