Global metabolic response in the bile of pejerrey (Odontesthes bonariensis, Pisces) sublethally exposed to the pyrethroid cypermethrin.

CARRIQUIRIBORDE, P.; MARINO, D.J.; GIACHERO, G.; CASTRO, E.A.; RONCO, A.E.

ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Año: 2012 vol. 76 p. 46 - 54

0147-6513

The metabolic profile of O. bonariensis, and its global response to the insecticide cypermethrin, was studied using HPLC-MS based metabolomics. Three experiments using either juveniles or adults of O. bonariensis were performed exposing fish (from 24 to 96h) to sublethal concentrations of cypermethrin (from 1 to 10µg/L). Metabolic profiling was performed either on whole bile or aqueous and organic extracts. Chromatography was performed using a C18 column and ACN/H20 mobile phase. ESI and APCI interfaces were used in positive and negative mode. Full scan MS data was processed using the XCMS software, log-transformed and analyzed using either regression analysis or PCA. The highest amount of information (1163 peaks/ions) was yielded analyzing the whole bile with the ESI(-) interface. Complementary information, useful for metabolite confirmation, was obtained from the aqueous and organic extracts and using the ESI(+) and APCI interfaces. Bile metabolic profile of O. bonariensis was characterized by some abundant metabolite ions corresponding with taurine conjugated bile acids and cholesterol, which were useful as reference peaks. A characteristic global metabolic response to cypermethrin was identified in the bile of O. bonariensis. Variations of abundance 10-fold or higher were observed in the whole bile of exposed fish for a small group of peaks (32), and these peaks were corresponded to an even smaller number of metabolites (19). Both regression analysis and PCA were useful to identify those peaks better explaining differences between exposed and control groups, but some different variables were proposed by each of the methods. Unsupervised PCA scores were able to distinguish organisms from each treatment on the basis of the metabolic changes induced by the cypermethrin, being this variability mainly explained by only one principal component (PC3, 17.7% total variance). Two cypermethrin metabolites were identified as major contributors within the augmented peaks: the known glucuronide of 4’-hydroxy-cypermethrin and the non-previously reported in fish bile sulfate of 4’-hydroxy-cypermethrin. The used HPLC-MS based metabolomic approach demonstrated to be a powerful ecotoxicological tool for identifying biological responses to pollutants, discovering new metabolic pathways and proposing specific biomarkers using non-model organisms