title: Oxidative stress response in zebrafish (Danio rerio) gill experimentally exposed to subchronic microcystin-LR.
abstract: The worldwide occurrence of cyanobacterial blooms makes it necessary to perform environmental risk assessment procedures to monitor the effects of microcytins on fish. Oxidative stress biomarkers are valuable tools in this regard. Considering that zebrafish (Danio rerio) is a common model species in fish toxicology and the zebrafish gill is potentially useful in screening waterborne pollutants, this study investigated the oxidative stress response in zebrafish gill exposed to subchronic microcystin-LR (MCLR) concentrations (2 or 20 μg/l) via measurement of toxin accumulation, protein phosphatase (PP) activity, and the antioxidant parameters (glutathione-S-transferase-GST; glutathione-GSH; superoxide dismutase-SOD; catalase-CAT; glutathione peroxide-GPx; glutathione reductase-GR), as well as levels of hydroxyl radical (OH) and lipid peroxidation (LPO). The results showed that after 30 days exposure, MCLR accumulated in zebrafish gill and MCLR exposure induced PP activity in gill. A linear inhibition of GST activity and GSH content was observed in the gills, revealing that they were involved in the first step of MCLR detoxification. The 2 μg/l MCLR treatment neglectably affected OH content and the antioxidant enzymes (SOD, CAT, GPx, and GR), however oxidative stress was induced under the 20 μg/l MCLR treatment in which an enhanced OH content and alterations of the antioxidant enzymes were observed in the treated gills, although both treatments exerted little effect on LPO level. The principal component analysis results indicated that the most sensitive biomarkers of MCLR exposure were GST and GSH in zebrafish gill. So, D. rerio could be regarded as a suitable bioindicator of MCLR exposure by measuring CAT, GR, GST, and GSH as biomarkers.
authors: Xiamen Marine Environmental Monitoring Center, Xiamen 361008, China. baby_680@xmu.edu.cn
authors: Yao
authors: Y
authors: Chen
authors: Song-Fu
authors: SF
authors: Zeng
authors: Yu-Feng
authors: YF
authors: Cao
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000633:toxicity; D005880:Gills / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D008387:Marine Toxins; D052998:Microcystins / Q000633:toxicity*; D018384:Oxidative Stress / Q000502:physiology; D013482:Superoxide Dismutase / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D015027:Zebrafish
chemical_list: D015415:Biomarkers; D004791:Enzyme Inhibitors; D008387:Marine Toxins; D052998:Microcystins; D014874:Water Pollutants, Chemical; D002374:Catalase; D013482:Superoxide Dismutase; D005980:Glutathione Reductase; D005982:Glutathione Transferase; C057862:cyanoginosin LR; D005978:Glutathione