Evaluation of the genotoxic potential of cypermethrin, chlorpyrifos and their subsequent mixture, on cultured bovine lymphocytes

Abstract

Cypermethrin (CYP) and chlorpyrifos (CPF) are insecticides/parasiticides used in the production of fruits,vegetables and beef cattle. These substances or their metabolites are frequently reported as residues infood, whose consumption in a diet implies a genotoxic risk. The potential for chronic toxicity of CYP andCPF is unclear, and only a few genotoxicological evaluations based on their mixture have been performed.The aim of this study was to evaluate the genotoxic potential of CYP, CPF and CYP þ CPF in five concentrations,from 5.9 to 175 mg/mL, on bovine lymphocytes. By means of the cytokinesis-block micronucleuscytome assay, a decrease in the cell proliferation index was observed (r ¼ 0.89 p ¼ 0.04); andalso an increase in the frequencies of binucleated cells (BN) with micronuclei (BNMn) (r ¼ 0.93, p ¼ 0.02)and BN with nuclear buds (BNBud) (r ¼ 0.778 p ¼ 0.04), depending on the concentrations of CPF. Anincrease in BNMn frequencies was observed as a function of CYP concentrations (r ¼ 0.89, p ¼ 0.04) andalso of the CYP þ CPF mix (r ¼ 0.99, p ¼ 0.008). CYP caused greater genotoxic damage (BNMn) than CPFand the mixture on bovine lymphocytes. Cells with simultaneous presentation of micronuclei and nuclearbuds were detected, as well as cells with irregular nuclei, something never previously reported,whose origin and significance should be investigated. The genotoxic effect of chlorpyrifos, cypermethrin and their mixture on bovine lymphocytes was observed. We recognized the value of the use of primarybovine cultures, animal species adjacent to man in the food chain, for genotoxicity studies.