Juvenile Sea Bass Liver Biotransformation Induction and Erythrocytic Genotoxic Responses to Resin Acids

Abstract

Juvenile Dicentrarchus labrax L. (sea bass) were exposed for 0, 2, 4, 6, and 8 h to abietic acid (AA) and dehydroabietic acid (DHAA) in concentration ranges 0, 0.0125, 0.025, 0.05, 0.1, 0.3, 0.9, and 2.7 μM. Liver cytochrome P-450 content (P450) and liver ethoxyresorufin-O-deethylase activity (EROD) were determined as phase I biotransformation biomarkers. Genotoxicity was measured as erythrocytic micronuclei (EMN) and nuclear abnormalities (ENA). Liver damage was assessed as liver alanine aminotransferase activity (ALT) and liver somatic index (LSI) was used as a general health indicator. AA inhibited EROD (at 2 h exposure to 0.05 μM) or failed to induce it, whereas a significant P450 increase was observed at 2 h exposure to 0.05 (2.3-fold) and 2.7 μM (6.3-fold). A significant P450 increase was also observed at 6 and 8 h exposure, respectively, to 0.0125 (3.4-fold) and 0.025 μM (4.9-fold) AA. EMN and ENA frequency were significantly increased at 2 h exposure to 0.9 μM AA. A significant EMN and ENA time-related increase was observed with an increased exposure length up to 8 h. Therefore, all the AA concentrations tested promoted an EMN and ENA increase at 8 h exposure. DHAA induced a significant EROD increase (3.2-fold) at 2 h exposure to the lowest concentration tested. Liver P450 was significantly increased at 2 h exposure to 0.025 (1.8-fold) and 0.3 μM (2.5-fold), at 4 h exposure to 0.1 μM (3.6-fold), and at 6 h exposure to 0.1 (3.2-fold) and 0.3 μM (2.8-fold), whereas it was significantly decreased (30% of control value) at 4 h exposure to 0.9 μM. EMN and ENA frequency were significantly increased from 0 to 2 h exposure to all DHAA concentrations tested and remained high from 2 to 8 h. EMN frequency was increased 20 times over control at 2 h exposure to 0.0125 μM DHAA, whereas it increased 9-fold at 2 h exposure to 0.9 μM AA. Furthermore, ENA frequency was increased 3 times over control at 2 h exposure to 0.0125 μM DHAA, and 2-fold after exposure to 0.9 μM AA. Maximal EMN and ENA induction was observed at 2 h exposure to 0.0125 μM DHAA and only at 4 h exposure to 2.7 μM AA. Therefore, the comparative analysis of the two resin acids genotoxic effects, measured as EMN and ENA, indicated that DHAA is more genotoxic than AA.