Cytogenetic Effects of Carbendazim on Mouse Bone Marrow Cells

Abstract

A study of the genotoxic activity of fungicide carbendazim was carried out. It was demonstrated that the tested technical grade active ingredient of carbendazim in the dose range of 125–2000 mg/kg body weight induced a statistically significant dose-dependent increase in the frequency of micronucleated polychromatic (PCE) and normochromatic erythrocytes (NCE) in the bone marrow of CD-1 mice. After administration of carbendazim at doses of 250–2000 mg/kg body weight, the accumulation of cells containing two or more micronuclei was observed. According to the results of comet assay, there was no increase in the level of breaks and alkali-labile sites in the DNA of the mouse bone marrow and liver cells after administration of technical grade carbendazim at doses up to 2000 mg/kg body weight. It is therefore suggested that the observed accumulation of cells with micronuclei is due to the aneugenic effect of carbendazim. In addition, a dose-dependent increase in the proportion of macrocytes/gigantocytes and dumbbell-shaped cells with constrictions among PCEs and NCEs was observed, which might be indicative of the inhibitory effect of the test pesticide on cytokinesis. The accumulation of polychromatophiles with pyknotic nuclei after exposure to carbendazim is probably caused by the distortion of nuclear extrusion. A possible general mechanism underlying the impairment of karyokinesis, cytokinesis, and nuclear extrusion in mammalian bone marrow erythroid cells is discussed.