title: Different effects of low- and high-dose waterborne zinc on Zn accumulation, ROS levels, oxidative damage and antioxidant responses in the liver of large yellow croaker Pseudosciaena crocea.
abstract: The aim of the present study was to assess survival rate, Zn accumulation, reactive oxygen species (ROS) levels, oxidative damage and antioxidant responses after Zn exposure (2 and 8 mg L-1Zn) at different exposure times (6, 12, 24, 48 and 96 h) in the liver of large yellow croaker. Survival rate was reduced at 96 h, and hepatic Zn content increased during 24-96 by 8 mg L-1Zn. In the 2 mg L-1Zn group, no fish died and the increase in Zn content merely occurred at 96 h. Exposure to 8 mg L-1Zn induced accumulation of ROS, lipid peroxidation and protein carbonylation during the late stage of exposure. In contrast, exposure to 2 mg L-1Zn did not result in oxidative damage, which may result from the up-regulation of antioxidant defenses. Although exposure to 8 mg L-1Zn increased activities and mRNA levels of antioxidant enzymes during the early stage of exposure, including Cu/Zn-SOD, Mn-SOD, CAT, GPx and GR, the activities of these enzymes except Cu/Zn-SOD were inhibited at 96 h. Furthermore, a sharp increase in Nrf2 expression was observed in fish exposed to 8 mg L-1at 6 and 12 h, and 2 mg L-1at 12 h and 24 h, suggesting that Nrf2 was required for the protracted induction of these genes. The late increase in Keap1 expression may support its role in switching off the Nrf2 response. In conclusion, the present study demonstrated different effects of low- and high-dose waterborne Zn on antioxidant responses, which could contribute to the understanding of antioxidant and toxic roles of zinc on a molecular level.
authors: National Engineering Research Center of Marine Facilities Aquaculture, Zhejiang Ocean University, Zhoushan, 316022, People's Republic of China.
authors: Jia-Lang
authors: JL
authors: Zheng
authors: National Engineering Research Center of Marine Facilities Aquaculture, Zhejiang Ocean University, Zhoushan, 316022, People's Republic of China.
authors: Lin
authors: L
authors: Zeng
authors: National Engineering Research Center of Marine Facilities Aquaculture, Zhejiang Ocean University, Zhoushan, 316022, People's Republic of China.
authors: Mei-Ying
authors: MY
authors: Xu
authors: National Engineering Research Center of Marine Facilities Aquaculture, Zhejiang Ocean University, Zhoushan, 316022, People's Republic of China.
authors: Bin
authors: B
authors: Shen
authors: National Engineering Research Center of Marine Facilities Aquaculture, Zhejiang Ocean University, Zhoushan, 316022, People's Republic of China. wucw2013@126.com.
authors: Chang-Wen
authors: CW
authors: Wu
mesh_terms: D000818:Animals; D002374:Catalase / Q000235:genetics; D029941:Fish Proteins / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D005979:Glutathione Peroxidase / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D051267:NF-E2-Related Factor 2 / Q000235:genetics; D018384:Oxidative Stress / Q000187:drug effects; D010473:Perciformes / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000235:genetics; D014874:Water Pollutants, Chemical / Q000493:pharmacokinetics / Q000633:toxicity*; D015032:Zinc / Q000493:pharmacokinetics / Q000633:toxicity*
chemical_list: D029941:Fish Proteins; D051267:NF-E2-Related Factor 2; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D014874:Water Pollutants, Chemical; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D005980:Glutathione Reductase; D015032:Zinc
keywords: Antioxidant response; Large yellow croaker; Waterborne zinc; Zn accumulation