Genotoxic effect of the insecticide Chlorpyrifos on the erythrocytes of Odontophrynus carvalhoi tadpoles (Amphibia: Odontophrynidae)

Márcio Borba Silva, Ricardo Evangelista Fraga, Patrícia Belini Nishiyama, Natália Layane Badaró Costa, Inaiara Sousa Siqueira da Silva, Tiago Sousa de Queiroz, Mariane Amorim Rocha, Flora Acuña Juncá


Chlorpyrifos is an organophosphate insecticide widely used and it acts as an inhibitor of cholinesterases, overstimulating the nerve endings. This study analyzed the genotoxic effect of the organophosphate insecticide Chlorpyrifos upon the induction of micronucleated erythrocytes in the blood of Odontophrynus carvalhoi Brazilian neotropical tadpoles submitted to four different nominal concentrations of this insecticide (10, 100, 200 e 400 mg L-1) during 96 hours. The tadpoles were anesthetized, euthanized and their blood was collected through cardiac puncture and later on cyto smears were performed and stained with May Grunwald Giemsa. The frequencies of micronucleated erythrocytes were determined at different periods of exposure (24h, 48h e 96h) through the analysis of 1000 erythrocytes for each tadpole. The tadpoles that were submitted to the Chlorpyrifos showed high frequencies of genetic changes (micronuclei) when compared with the negative control. The differences in the frequencies of the micronuclei registered after 48 hours of exposure were statistically significant (p<0.05). Thus, it can be concluded that tadpoles of O. carvalhoi were susceptible to genetic alterations induced by the use of the commercial formulation of chlorpyrifos (Klorpan®), showing a clastogenic effect in the erythrocytes of this species. The use of this species as an animal model for genotoxic studies has shown promise.

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