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Nereis virens (Annelida: Polychaeta) is not an adequate sentinel species to assess the genotoxic risk (Comet assay) of PAH exposure to the environment

par De Boeck, Marlies;Kirsch-Volders, Micheline
Référence Environmental and molecular mutagenesis, 30, 1, page (82-90)
Publication Publié, 1997

Article révisé par les pairs

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Résumé :

Polychaetes, because of their bioturbation capacity, play an important role in the distribution of anthropogenic contaminants (including polycyclic aromatic hydrocarbons [PAHs]) throughout the sediments. In this work the use of Nereis virens (Annelida: Polychaeta) as a bioindicator to assess the genotoxic risk of PAH exposure for the environment was evaluated. For this purpose the alkaline single cell gel electrophoresis (comet) assay was applied on the coelomocytes of in vivo exposed Nereis virens. Benzo[a]pyrene (B[a]P) was chosen because it is classified by the IARC [international Agency for Research on Cancer) as 'probably carcinogenic to humans' and because its mechanisms of action are well-known. Nereis virens was exposed to B[a]P in concentrations of 0.3, 0.6, 10, 20, 35 and 45 mg/ ml by an intracoelomic injection of B[a]P (20 μl) dissolved in dimethyl sulphoxide (DMSO). A solvent control with DMSO, a positive control with ethyl methane sulphonate (EMS) (12.1 mg/ml) and a negative control were included in each experiment. For each treatment four animals were analysed. After 1 hr treatment coelomocytes were harvested by puncturing the coelomic cavity with a sharpened Pasteur pipette, mixed with 0.5% low melting point agarose and sandwiched between two other gel layers. Ethidium bromide stained nuclei were analysed For tail length and tail moment. 12.1 mg/ml EMS, pure DMSO (98.9%) and B[a]P in all tested concentrations induced a statistically significant increase of DNA single strand breaks in the comet assay. The effect of B[a]P, however, was only at the highest concentration 145 mg/ml) significantly stronger than the effect of DMSO alone. Although a relatively large heterogeneity in the results could be observed, these experiments clearly showed that Nereis virens is not suited as a sentinel species for the assessment of the genotoxic risk of PAH exposure because this species seems to be very resistant to benzo[a]pyrene.