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 in food, whose consumption in a diet implies a genotoxic risk. The potential for chronic toxicity of CYP and CPF 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 + CPF in five concentrations, from 5.9 to 175 µg/mL, on bovine lymphocytes. By means of the cytokinesis-block micronucleus cytome assay, a decrease in the cell proliferation index was observed (r = -0.89 p = 0.04); and also an increase in the frequencies of binucleated cells (BN) with micronuclei (BNMn) (r = 0.93, p = 0.02) and BN with nuclear buds (BNBud) (r = 0.778 p = 0.04), depending on the concentrations of CPF. An increase in BNMn frequencies was observed as a function of CYP concentrations (r = 0.89, p = 0.04) and also of the CYP + CPF mix (r = 0.99, p = 0.008). CYP caused greater genotoxic damage (BNMn) than CPF and the mixture on bovine lymphocytes. Cells with simultaneous presentation of micronuclei and nuclear buds 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 primary bovine cultures, animal species adjacent to man in the food chain, for genotoxicity studies.
