Oxidative stress, liver biotransformation and genotoxic effects induced by copper in Anguilla anguilla L.--the influence of pre-exposure to beta-naphthoflavone.
Fish are exposed in the aquatic ecosystems to different classes of pollutants. Polycyclic aromatic hydrocarbons (PAHs) and heavy metals represent two important classes of aquatic contaminants. Thus, one lot of European eels (Anguilla anguilla L.) was pre-exposed during 24 h to 2.7 microM beta-naphthoflavone (BNF; a PAH-like compound), and subsequently exposed during 24 h to 0, 1 and 2.5 microM copper (Cu). Additionally, another lot not pre-exposed to BNF was exposed to the same Cu concentrations. BNF pre-exposure promoted a significant increase in liver ethoxyresorufin O-deethylase (EROD) activity, but did not change the other responses investigated in eels. On the other hand, both Cu concentrations did not modify the liver EROD activity either in eels pre-exposed to BNF or not. Liver total cytochrome P450 was increased in eels exposed to Cu 2.5 microM, being significantly only in eels not pre-exposed to BNF. Free sulfhydryl group content was decreased by 1 and 2.5 microM in eels pre-exposed to BNF or not pre-exposed, being significant at 2.5 microM Cu in eels not pre-exposed compared to its control. Liver total glutathione (TG), reduced glutathione (GSH) and GSH/oxidized glutathione (GSSG) levels were slightly decreased by 1 and 2.5 microM Cu in eels pre-exposed to BNF, whereas a slight tendency to increase was observed in eels not pre-exposed. Thus, liver TG and GSH significantly decreased in 2.5 microM Cu BNF pre-exposed eels compared to eels not pre-exposed to BNF. Liver glutathione reductase and catalase activities were significantly inhibited by 1 and 2.5 microM Cu in eels pre-exposed to BNF, concomitantly with a slight liver glutathione peroxidase tendency to decrease. Lipid peroxidation was significantly increased by 1 microM Cu in eels either pre-exposed or not pre-exposed to BNF. Liver H(2)O(2) was significantly increased by 1 microM Cu in eels pre-exposed to BNF. Liver DNA integrity was significantly decreased by 1 and 2.5 microM Cu in eels pre-exposed to BNF. The oxidative stress and genotoxic effects induced by Cu in eels pre-exposed to BNF revealed that the metal effects are potentiated by previous exposure to BNF.
Gravato
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Department of Biology, University of Aveiro, 3810-193 Aveiro, Portugal. gravatoc@bio.ua.pt
Teles
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Oliveira
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Santos
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D000811:Anguilla / Q000378:metabolism*; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001711:Biotransformation; D003300:Copper / Q000493:pharmacokinetics / Q000633:toxicity*; D019363:Cytochrome P-450 CYP1A1 / Q000187:drug effects; D003577:Cytochrome P-450 Enzyme System / Q000187:drug effects / Q000378:metabolism; D004249:DNA Damage; D004798:Enzymes / Q000187:drug effects / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D005982:Glutathione Transferase / Q000187:drug effects / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D009152:Mutagenicity Tests; D018384:Oxidative Stress; D014874:Water Pollutants, Chemical / Q000493:pharmacokinetics / Q000633:toxicity*; D019324:beta-Naphthoflavone / Q000633:toxicity*
D000975:Antioxidants; D004798:Enzymes; D014874:Water Pollutants, Chemical; D019324:beta-Naphthoflavone; D003300:Copper; D003577:Cytochrome P-450 Enzyme System; D006861:Hydrogen Peroxide; D019363:Cytochrome P-450 CYP1A1; D005982:Glutathione Transferase; D005978:Glutathione