Does uranium exposure induce genotoxicity in the teleostean Danio rerio? First experimental results

¹ Laboratory of Radioecology and Ecotoxicology, IRSN (Institute for Radioprotection and Nuclear Safety), DEI/SECRE/LRE, Cadarache, Bd. 186, BP. 3, 13115 St-Paul-Lez-Durance Cedex, France, e-mail: sabrina.barillet@irsn.fr
² Environnemental Science Laboratory (LSE), ENTPE, 69518 Vaulx en Velin Cedex and INRA, EFPA department, 34398 Montpellier Cedex 5, France

Abstract

Zebrafish were exposed to different concentrations of waterborne uranium (0, 20, 100 and 500 μg U.L^-1) and were sacrificed for blood sampling after different exposure periods (12h, 36h, 72h, 5, 10 and 20 days) in order to assess DNA integrity in erythrocytes, using the comet assay and flow cytometry. Concurrently, uranium bioaccumulation was studied in the remaining tissues to understand the potential genotoxic biomarker responses. Both genotoxic assays revealed significant effect of waterborne uranium on DNA integrity of fish erythrocytes. However, comet assay only succeeded in detecting such an effect after a 20-day exposure whereas flow cytometry analysis showed a uranium concentration effect for any exposure duration. Regarding uranium bioaccumulation, significant effects of both uranium concentration and exposure duration have been highlighted in this experiment.