Spermatozoa: A relevant biological target for genotoxicity assessment of contaminants in the estuarine bivalve Scrobicularia plana.

Evaluation of DNA quality of gametes is a relevant method to predict potential consequences of pollutants in the next generations, as it allows to define adverse outcome pathways implicated in pollutant-mediated toxicity for risk assessment. In the present study, a comet assay was developed for the spermatozoa of Scrobicularia plana exposed to 10 and 100μg/L of benzo[a]pyrene (B[a]P) for 24h and 5days. The induction of apoptosis and repair mechanisms was assessed by determining caspase-3 activity and polymerase cell nuclear antigen (PCNA) mRNA expression level. Results showed that B[a]P induced high levels of DNA breaks that were associated with apoptosis for all the conditions tested, indicating that the spermatozoa were sensitive to B[a]P. PCNA gene expression was induced in animals exposed to the highest concentrations of B[a]P, suggesting that defence mechanisms were enhanced in these animals. This preliminary study demonstrated the utility of spermatozoa as a relevant biological target for genotoxicity assessment of contaminants and will enable to predict the effect of contaminants on future generations.