title: Effects of chronic exposure of 2,4-dichlorophenol on the antioxidant system in liver of freshwater fish Carassius auratus.
abstract: There were few reports on the antioxidant response of aquatic organisms exposed to 2,4-dichlorophenol (2,4-DCP). This research explored the hepatic antioxidant responses of fish to long-term exposure of 2,4-DCP for the first time. Freshwater fish Carassius auratus were chosen as experimental animals. The fish were exposed to six different concentrations of 2,4-DCP (0.005-1.0 mg/l) for 40 days and then liver tissues were separated for determination. As shown from the results, 40 days afterwards, the activities of catalase (CAT) and selenium-dependent glutathione peroxidase (Se-GPx) and the content of oxidized glutathione (GSSG) were induced significantly on the whole compared to control group; superoxide dismutase (SOD) responded to 2,4-DCP exposure at only 0.005 mg/l; the content of reduced glutathione (GSH) was suppressed continuously except Group 7; the activity of glutathione reductase was inhibited initially and then restored to control level from Group 4 on; glutathione S-transferase had only slight responses in Groups 3 and 4. Total glutathione (tGSH) and GSH/GSSG ratio were also calculated to analyze the occurrence of oxidative stress. Besides, good dose-effect relations, which cover most of the exposure concentration range, were found between 2,4-DCP level and CAT activity, GSSG content, Se-GPx activity, respectively. In conclusion, SOD and Se-GPx may be potential early biomarkers of 2,4-DCP contamination in aquatic ecosystems, and further studies will be necessary.
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, School of Environment, Nanjing University, Nanjing 210093, People's Republic of China.
authors.forename: Jingfei
authors.initials: J
authors.lastname: Zhang
authors.forename: Hua
authors.initials: H
authors.lastname: Shen
authors.forename: Xiaorong
authors.initials: X
authors.lastname: Wang
authors.forename: Jichun
authors.initials: J
authors.lastname: Wu
authors.forename: Yuqun
authors.initials: Y
authors.lastname: Xue
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002374:Catalase / Q000378:metabolism; D002681:China; D002733:Chlorophenols / Q000633:toxicity*; D005618:Fresh Water; D005978:Glutathione / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D006054:Goldfish / Q000378:metabolism*; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D002733:Chlorophenols; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D005978:Glutathione; C004762:2,4-dichlorophenol