title: Effects of chronic exposure of methomyl on the antioxidant system in kidney of Nile tilapia (Oreochromis niloticus) and recovery pattern.
abstract: Tilapia were exposed to sublethal methomyl concentrations of 0, 0.2, 2, 20, or 200 μg/L for 30 d, and then were transferred to methomyl-free water for 18 d. Renal antioxidant parameters, including catalase (CAT), superoxide dismutase (SOD), glutathione S-transferase (GST), glutathione peroxidase (GPx) , glutathione reductase (GR), total glutathione (GSH), and reduced glutathione (GSSG), were examined in tilapia at d 0, 6, 12, 18, 24, and 30 after starting the experiment and at 18 d after transferring to methomyl-free water. There were no significant changes in enzymatic activity and content of antioxidants in kidney of tilapia exposed to 0.2 μg/L methomyl compared to controls. The results showed significant increases in SOD, CAT, GST, GR, GPx, and level of GSSG accompanied by a decrease in GSH levels following methomyl exposure in tilapia to 2, 20, or 200 μg/L over the 30-d exposure period, suggesting the presence of oxidative stress. Thus, it would appear the 0.2 μg/L methomyl might be considered the no-observed-adverse-effect level (NOAEL). Recovery data showed that the effects produced by lower concentration of methomyl at 20 μg/L were reversible but not at the higher 200 μg/L concentration.
authors.affiliation: a Wuxi Fishery College, Nanjing Agricultural University , Wuxi , China.
authors.forename: Shun Long
authors.initials: SL
authors.lastname: Meng
authors.forename: Geng Dong
authors.initials: GD
authors.lastname: Hu
authors.forename: Li Ping
authors.initials: LP
authors.lastname: Qiu
authors.forename: Chao
authors.initials: C
authors.lastname: Song
authors.forename: Li Min
authors.initials: LM
authors.lastname: Fan
authors.forename: Jia Zhang
authors.initials: JZ
authors.lastname: Chen
authors.forename: Pao
authors.initials: P
authors.lastname: Xu
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D023681:Cichlids / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D007306:Insecticides / Q000633:toxicity*; D007668:Kidney / Q000187:drug effects* / Q000201:enzymology; D008297:Male; D008724:Methomyl / Q000633:toxicity*; D019055:No-Observed-Adverse-Effect Level; D018384:Oxidative Stress / Q000187:drug effects*; D010088:Oxidoreductases / Q000378:metabolism; D018675:Toxicity Tests; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D015415:Biomarkers; D007306:Insecticides; D014874:Water Pollutants, Chemical; D008724:Methomyl; D010088:Oxidoreductases