title: Teratogenicity, genotoxicity and oxidative stress in zebrafish embryos (Danio rerio) co-exposed to arsenic and atrazine.
abstract: Arsenic and atrazine are common environmental contaminants probably due to their extensive use as pesticides on agricultural farmlands. In this study, zebrafish embryos were exposed to 0.8mM arsenic, 0.1mM atrazine or mixture of both for 96h, and various indices which are indicative of teratogenicity (egg coagulation, growth retardation, edema formation, hatching success, scoliosis), genotoxicity (DNA tail moments) and oxidative stress (lipid peroxidation and reduced glutathione (GSH) levels, catalase and glutathione peroxidase activities) were determined. The negative control were exposed to 0.5% DMSO while the positive control group were exposed to 4mg/L 3,4 dichloroaniline. Egg coagulation was highest in the positive control (85%), followed by the group that was exposed to mixture of arsenic and atrazine (30%) and least in the arsenic-exposed group (20%). The incidences of edema (59%) and growth retardation (35.2%) were more frequent in the group that was exposed to contaminant mixture and least in atrazine-exposed group where incidences of both edema and growth retardation were 15%. The incidence of scoliosis ranged between 20% in arsenic-exposed group and 10% in atrazine-exposed group. Hatching success was generally high in all the groups ranging between 95% in atrazine-exposed group and 88% in the group that was exposed to mixture of arsenic and atrazine. There was no evidence of teratogenic effect in the negative control group. DNA tail moments and lipid peroxidation levels increased significantly while GSH levels and catalase activity decreased significantly in contaminant-exposed groups, especially the mixture compared to the negative control. There was no significant change in GPx activity in the exposed groups compared to the negative control. The results of this study demonstrate that both arsenic and atrazine are potentially teratogenic and genotoxic, and can cause oxidative stress in zebrafish embryos, and these effects are potentiated by toxic interactions between the two contaminants.
authors.affiliation: Department of Clinical Analyses, Toxicology and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Avenida do Café s/n°, CEP 14040-903, Ribeirão Preto, São Paulo, Brazil; Department of Biological Sciences, Faculty of Basic and Applied Sciences, Osun State University, P.M.B. 4494 Osogbo, Osun State, Nigeria. Electronic address: joseph.adeyemi@gmail.com.
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Adeyemi
authors.affiliation: Department of Clinical Analyses, Toxicology and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Avenida do Café s/n°, CEP 14040-903, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Airton
authors.initials: A
authors.lastname: da Cunha Martins-Junior
authors.affiliation: Department of Clinical Analyses, Toxicology and Food Sciences, School of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Avenida do Café s/n°, CEP 14040-903, Ribeirão Preto, São Paulo, Brazil.
authors.forename: Fernando
authors.initials: F
authors.lastname: Barbosa
mesh_terms: D000818:Animals; D001151:Arsenic / Q000633:toxicity*; D001280:Atrazine / Q000633:toxicity*; D002273:Carcinogens / Q000633:toxicity; D020552:Comet Assay; D004249:DNA Damage; D004625:Embryo, Nonmammalian / Q000187:drug effects*; D004785:Environmental Pollutants / Q000633:toxicity; D005978:Glutathione; D006540:Herbicides / Q000633:toxicity*; D015227:Lipid Peroxidation; D018384:Oxidative Stress / Q000187:drug effects*; D017392:Thiobarbituric Acid Reactive Substances; D015027:Zebrafish
chemical_list: D002273:Carcinogens; D004785:Environmental Pollutants; D006540:Herbicides; D017392:Thiobarbituric Acid Reactive Substances; D005978:Glutathione; D001151:Arsenic; D001280:Atrazine
keywords: Arsenic; Atrazine; Comet assay; Contaminant mixture; Oxidative stress; Teratogenicity