The presence of genotoxic agents in the environment may cause chromosomal mutations through different mechanisms, which are associated with serious health effects. Genotoxicity is commonly evaluated for the chemical safety assessment, in which the in vivo micronucleus test is paid more attention in the field of genotoxicity as compared to other toxicological endpoints. This assay is an in vivo cytogenetic test which uses erythrocytes in the bone marrow of rodents to detect chemical damage to the chromosomes or mitotic apparatus of mammalian cells. At the time of erythroblast development into a polychromatic erythrocyte (PCEs) in bone marrow, the main nucleus is extruded, so any micronucleus (MN) that has been formed may remain behind in the otherwise anucleated cytoplasm. The damage in the chromosome appears as a small additional nucleus and is readily identifiable by light microscope. An increase in the frequency of micronucleated polychromatic erythrocytes (MN PCEs) in treated animals is an indication of genotoxicity.
Keywords: Bone marrow May–Grunwald stain; Giemsa stain; In vivo MN; Micronucleus; NCEs; Normochromatic erythrocyte; PCEs; Polychromatic erythrocyte.