Genotoxicity of pesticides: the role of non-active ingredients

Amitraz is a formamidine-based insecticide and acaricide used in veterinary applications. Despite the use of various genetic assessment criteria and testing systems to investigate amitraz poisoning, studies have yielded diverse and inconclusive results. This study aimed to analyze the genotoxic potential of the insecticide amitraz and compare the effects of the active constituent and a commercial product containing amitraz. Chinese hamster ovary cells were cultured during one cellular cycle in Ham F12 medium containing 1.25, 2.5 and 3.75 μg mL-1 of amitraz. Quantitative comet and cytokinesis-block micronucleus assay were employed to evaluate the potential genotoxic effect. All genotoxicity parameters evaluated clearly demonstrated the capability of the commercial amitraz formulation to negatively affect DNA, inducing both cytogenetic and cytomolecular damage. After culturing the cells with the active component of the formula, only a slight, non-significant increase in damage was found. Since our findings showed that the active component of the formula is not the sole responsible for the genotoxic effect of the commercial product, we emphasize the importance of considering the adverse effects of the solvents used in commercial pesticide formulations.