Biomarkers of genotoxicity and genomic instability in a non-human primate, Cebus libidinosus (Cebidae, Platyrrhini), exposed to nitroimidazole derivatives

The genotoxicity of two nitroimidazole derivatives, ornidazole (ONZ) and metronidazole (MTZ) in the peripheral blood lymphocytes of Cebus libidinosus (CLI) (Primates, Cebidae) was assessed. Endpoints measured included sister chromatid exchange (SCE) frequency, cell proliferation kinetics (CPK), replication index (RI), mitotic index (MI), and damage incidence in or near CLI heterochromatin regions. MI and SCE values following ONZ or MTZ treatments were significantly different (p < 0.001) from control. SCE frequency per chromosome was not proportional to chromosome length. The chromosomes most affected for SCE were 1, 2, 4, 6, 11–13, 17, and 18, many of which possess interstitial or terminal heterochromatin. In the CLI genome, chromosomes 11 and 17 showed higher susceptibility to damage RI was the only biomarker that did not show statistically significant differences between control and treated cultures. C. libidinosus bands 11q1.4 and 11q1.5 may be hot-spots in the context of nitroimidazole exposure.