title: Detection of DNA damage in yolk-sac larvae of the Japanese Medaka, Oryzias latipes, by the comet assay.
abstract: This study was set up to determine the suitability of the early life stage (ELS) alkaline comet assay for the detection of DNA strand breaks induced by genotoxicants in whole organism. This assay was performed on cells of medaka 2 days posthatch (dph). An efficient procedure for cell dissociation using enzymatic and mechanical digestion was developed. This protocol ensures 80% viability of cells and low DNA damage background. Cells from 2 dph medaka larvae were exposed in vitro to model genotoxicants, hydrogen peroxide, cadmium, and fluoranthene, followed by comet assay analysis. Results show a significant increase in the percentage of DNA damage of dissociated cells by all the tested compounds when compared to controls. The assay was also performed in vivo on medaka larvae (2 dph) exposed for 24 h to waterborne cadmium or fluoranthene. Significant induction of DNA damage levels were observed following larvae exposure to cadmium and fluoranthene at concentrations of 0.1 and 50 μM, respectively. This study demonstrates that cells of embryo life stage medaka respond to known DNA damaging agents and that the ELS comet assay may be a useful biomarker to detect DNA strand breakage in whole body of pluricellular organism induced by a range of agents. This technique may provide a sensitive, nonspecific endpoint of genotoxicity as part of ELS toxicity test.
authors.affiliation: Institute of Molecular Sciences (ISM), University Bordeaux 1, UMR 5255 CNRS, Group LPTC, 33405 Talence Cedex, France. b.morin@ism.u-bordeaux1.fr
authors.forename: Bénédicte
authors.initials: B
authors.lastname: Morin
authors.forename: Julien
authors.initials: J
authors.lastname: Filatreau
authors.forename: Ludovic
authors.initials: L
authors.lastname: Vicquelin
authors.forename: Iris
authors.initials: I
authors.lastname: Barjhoux
authors.forename: Sylvain
authors.initials: S
authors.lastname: Guinel
authors.forename: Joelle
authors.initials: J
authors.lastname: Leray-Forget
authors.forename: Jérôme
authors.initials: J
authors.lastname: Cachot
mesh_terms: D000818:Animals; D019256:Cadmium Chloride / Q000633:toxicity; D020552:Comet Assay / Q000379:methods*; D004249:DNA Damage / Q000187:drug effects; D005449:Fluorenes / Q000633:toxicity; D007814:Larva / Q000737:chemistry* / Q000187:drug effects / Q000235:genetics; D009990:Oryzias / Q000196:embryology / Q000235:genetics*
chemical_list: D005449:Fluorenes; C007738:fluoranthene; D019256:Cadmium Chloride