In Vivo Genotoxicity and Cytotoxicity Assessment of Allowable Concentrations of Nickel and Lead: Comet Assay and Nuclear Abnormalities in Acridine Orange Stained Erythrocytes of Common. Carp (Cyprinus carpio L.)

The aim of the present study was to assess the possibility of in vivo genotoxicity by nickel and lead concentrations considered safe by regulatory agencies. In order to evaluate their genotoxic and cytotoxic potential, young specimens of the common carp (Cyprinus carpio L.) were exposed for 72 h in laboratory conditions to different concentrations of Ni and Pb, considered as annual average according to DIRECTIVE 2008/105/EC. The alkaline comet assay in circulating erythrocytes was applied and blood smears stained with acridine orange were tested for the presence of micronuclei and other nuclear abnormalities. The comet parameters % tail DNA and tail moment indicated statistically significant genotoxic damage for both metals at 100%, 75% and 50% of the permissible concentrations, as compared to controls. Increased levels of micronuclei were not observed in carp erythrocytes, but we found a significant increase in other nuclear abnormalities-notched, blebbed, lobed, eight-shaped nuclei and nuclear buds. This demonstrated evident cytotoxic effects and confirmed the use of nuclear abnormalities as an effective biomarker. The obtained results confirmed the genotoxic and cytotoxic effects of Ni and Pb, even at low permissible levels, and illustrated the need for additional investigations in order to reduce the allowable concentrations of heavy metals in water basins.