Naphthalene and beta-naphthoflavone effects on Anguilla anguilla L. hepatic metabolism and erythrocytic nuclear abnormalities.
The effects of a polycyclic aromatic hydrocarbon (PAH) such as naphthalene (NAP)--an environmental contaminant--and beta-naphthoflavone (BNF)--a model substance (PAH-like compound)--were investigated in European eel (Anguilla anguilla L.) over 3-, 6-, and 9-day exposure (0.1-2.7 microM). Both xenobiotics revealed to be strong biotransformation (phase I) inducers. After 3-day exposure, liver ethoxyresorufin O-deethylase (EROD) activity was significantly increased by all NAP and BNF tested concentrations. At 6 and 9 days, liver EROD activity was significantly induced mainly by the highest NAP and BNF concentrations. Liver cytochrome P450 content was significantly induced after 3-day exposure to 0.9 and 2.7 microM BNF and 9-day exposure to 0.1, 0.3 and 0.9 microM NAP. Liver alanine transaminase (ALT) activity was measured as an indicator of hepatic health condition, revealing a significant decrease after 6-day exposure to 0.9 microM BNF. Genotoxicity measured as erythrocytic nuclear abnormalities (ENA) was detected in all BNF treated fish on day 6, whereas on day 9, ENA frequencies returned to control levels, significantly decreasing at 0.9 microM BNF exposure. Immature erythrocytes (IE) frequency demonstrated a decreasing tendency along the BNF experiment and concomitantly with the above ENA response. The present experimental results elect EROD activity in A. anguilla as a useful short- to medium-term biomarker of exposure to both PAH and PAH-like compounds. However, some problems can emerge in the presence of high xenobiotic concentrations. Concerning genotoxicity, it is hypothesized that ENA response depends on different factors such as the exhaustion of the detoxification process, the balance erythropoiesis/erythrocytic catabolism and the DNA repairing capacity.
Pacheco
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M
Department of Biology, University of Aveiro, Portugal. mpacheco@bio.ua.pt
Santos
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MA
D000410:Alanine Transaminase / Q000187:drug effects / Q000494:pharmacology; D000811:Anguilla / Q000502:physiology*; D000818:Animals; D001711:Biotransformation; D019363:Cytochrome P-450 CYP1A1 / Q000187:drug effects* / Q000494:pharmacology; D004249:DNA Damage; D004260:DNA Repair; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000009:adverse effects* / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000201:enzymology; D009281:Naphthalenes / Q000009:adverse effects* / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000009:adverse effects* / Q000378:metabolism; D019324:beta-Naphthoflavone / Q000009:adverse effects* / Q000378:metabolism
D004791:Enzyme Inhibitors; D009281:Naphthalenes; D014874:Water Pollutants, Chemical; C031721:naphthalene; D019324:beta-Naphthoflavone; D019363:Cytochrome P-450 CYP1A1; D000410:Alanine Transaminase