Biomarker responses in liver of zebrafish (Danio rerio) after acute exposure to sublethal concentration of triclosan in water

SCARCIA, PAOLA; DE LA TORRE, FERNANDO; SAGER, EMANUEL; ROSSI, ANDREA; MARINO, DAMIÁN

Santos-SP

Congreso; SETAC Latin America 12th Biennial Meeting; 2017

SETAC

Triclosan (TC) is a widely used antibacterial/antifungal compound found in gels, toothpaste, deodorants, etc. The responses of hepatic biomarkers were evaluated in zebrafish (Danio rerio) after acute exposure to two sublethal concentrations of TC. Fish (391 ± 58 mg) were exposed to nominal concentrations of TC in water: 160 µg/L (TC1) and 340 μg/L (TC2) using a stock solution of TC dissolved in methanol, with a continuous flow system. Control fish remained in unchlorinated water (Ctrl) and water with the maximum concentration of methanol used (CtrlSv). Water samples were taken for determining TC exposure concentration by HPLC-MS. After 48 hours, fish were anesthetized, measured, weighed, sacrificed, and the liver was excised. Pooled samples were made up from 4 individuals, and 8 samples per treatment were processed (n=128). Enzymatic and non-enzymatic biomarkers were evaluated: activities of glutathione-S-transferase (GST), superoxide dismutase (SOD) and catalase (CAT), total antioxidant capacity against peroxyl radicals (ACAP) and lipid peroxidation levels as thiobarbituric acid reactive substance (TBARS). Statistical differences (p˂0.05) between groups were determined using analysis of variance followed by Tukey`s test. No fish mortality was observed during assay period. There were no significant differences between Ctrl and CtrlSv in the different biomarkers tested. In addition no significant difference in SOD activity and ACAP level were observed. Acute exposure to TC promoted significant increase in TBARS levels by 20% in TC1 and TC2 with respect to Ctrl. However, an inhibition in CAT activity was detected in zebrafish exposed to TC1 (-24%) and TC2 (-34%) while GST activity decreased by 24% in both concentration relative to Ctrl. These results suggest that acute exposure of zebrafish to TC promoted an inhibitory response in liver at both, antioxidant activity (CAT) and biotransformation (GST). Furthermore, exposure to TC showed that lipid peroxidation in liver was promoted. Finally, both tested TC concentrations lead to similar biomarker responses after acute exposure.