Biomarkers responses in juvenile rainbow trout (Oncorhynchus mykiss) after single and combined exposure to low doses of cadmium, zinc, PCB77 and 17beta-estradiol

Selim Ait-Aissa (1) , Olivier Ausseil (2) , Olivier Palluel (1) , Eric Vindimian (1) , Jacqueline Garnier-Laplace (2) , Jean-Marc Porcher (1)

1 INERIS - Institut National de l'Environnement Industriel et des Risques
2 IRSN - Institut de Radioprotection et de Sûreté Nucléaire

The objective of this study was to examine biochemical responses of rainbow trout exposed to sublethal water concentrations of metals, cadmium (Cd, 1.5 micro g/L) and zinc (Zn, 150 micro g/L) and potential combined effects when applied in mixture (Cd/Zn) with/without co-exposure to model organic chemicals 3,3',4,4'-tetrachlorobiphenyl (PCB77, 1 mg/kg) and 17--estradiol (E2, 0.5 mg/kg). After 21 days of exposure, several biomarkers were assessed in the liver [enzymatic and non enzymatic antioxidants, heat shock proteins (HSP70 and 60), ethoxyresorufin-O-deethylase (EROD)] and in the plasma [vitellogenin (Vtg), aminotransferases]. Plasma aminotransferases were not affected by the treatments, whereas other biomarkers showed different patterns of response in function of the treatment. For example, Cd, and Zn to a lesser extent, induced an adaptive response in the liver shown by an increase of antioxidant defences [total glutathione (GSH), superoxide dismutase (SOD), Trolox equivalent antioxidant capacity (TEAC)], without any impairment of GSH redox status nor induction of HSPs. Antagonistic effects were observed on GSH-related biomarkers after Cd/Zn exposure. PCB77 strongly induced EROD activity, HSP70, and TEAC. Co-exposure with metals did not modulate significantly the effects of PCB77. E2 induced Vtg and inhibited liver antioxidants and basal EROD activity. These inhibitory effects were suppressed in fishes exposed to E2+Cd/Zn, suggesting additive effects of E2 and metals. In addition, E2-induced Vtg was not altered by metals. Multivariate analyses confirmed some correlation between biomarkers, the use of complementary biomarkers is necessary to discriminate the different treatments and to highlight interactive effects.

Mots clés: DEPOT MINIER; CHARBON; GUIDE<br />---<br />ENVIRONMENTAL CONCENTRATIONS; OXIDATIVE STRESS; HEAT SHOCK PROTEIN; CYTOCHROME P450 1A; METAL ACCUMULATION; PRINCIPAL COMPONENT ANALYSIS; FACTOR CORRESPONDENCE ANALYSIS

Domaines: Ecotoxicologie; Sciences de l'environnement

Selim Ait-Aissa, Olivier Ausseil, Olivier Palluel, Eric Vindimian, Jacqueline Garnier-Laplace, et al.. Biomarkers responses in juvenile rainbow trout (Oncorhynchus mykiss) after single and combined exposure to low doses of cadmium, zinc, PCB77 and 17beta-estradiol. Biomarkers, 2003, 8 (6), pp.491-508. ⟨10.1080/13547500310001640037⟩. ⟨ineris-00961882⟩