title: Genotoxicity of acute and chronic gamma-irradiation on zebrafish cells and consequences for embryo development.
abstract: The effects of radiation on biological systems have been studied for many years, and it is now accepted that direct damage to DNA from radiation is the triggering event leading to biological effects. In the present study, DNA damage induced by acute or chronic irradiation was compared at the cellular (zebrafish [Danio rerio] cell line ZF4) and developmental (embryo) levels. Zebrafish ZF4 cells and embryos (at 3 h postfertilization) were exposed within ranges of acute doses (0.3-2 Gy/d) or chronic dose rates (0.1-0.75 Gy/d). DNA damage was assessed by immunodetection of γ-H2AX and DNA-PK (DNA double-strand breaks) and the alkaline comet assay (DNA single-strand breaks). Zebrafish embryo development and DNA damage were examined after 120 h. At low doses, chronic irradiation induced more residual DNA damage than acute irradiation, but embryo development was normal. From 0.3 Gy, a hyper-radiosensitivity phenomenon compared to other species was shown for acute exposure with an increase of DNA damage, an impairment of hatching success, and larvae abnormalities. These results suggest a dose-dependent correlation between unrepaired DNA damage and abnormalities in embryo development, supporting the use of DNA repair proteins as predictive biomarkers of ionizing radiation exposure. This could have important implications for environmental protection.
authors.affiliation: Institut de Radioprotection et de Sûreté Nucléaire, DEI/SECRE/LRE, Cadarache, France. sandrine.pereira@ymail.com
authors.forename: Sandrine
authors.initials: S
authors.lastname: Pereira
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Bourrachot
authors.forename: Isabelle
authors.initials: I
authors.lastname: Cavalie
authors.forename: Delphine
authors.initials: D
authors.lastname: Plaire
authors.forename: Morgan
authors.initials: M
authors.lastname: Dutilleul
authors.forename: Rodolphe
authors.initials: R
authors.lastname: Gilbin
authors.forename: Christelle
authors.initials: C
authors.lastname: Adam-Guillermin
mesh_terms: D000818:Animals; D002460:Cell Line; D020552:Comet Assay; D004247:DNA / Q000528:radiation effects; D053903:DNA Breaks, Double-Stranded; D004249:DNA Damage; D004625:Embryo, Nonmammalian / Q000528:radiation effects*; D047108:Embryonic Development / Q000528:radiation effects*; D005260:Female; D005720:Gamma Rays / Q000009:adverse effects*; D008297:Male; D009152:Mutagenicity Tests; D011836:Radiation Tolerance; D014875:Water Pollutants, Radioactive / Q000633:toxicity*; D015027:Zebrafish / Q000196:embryology
chemical_list: D014875:Water Pollutants, Radioactive; D004247:DNA