Cytogenetic Alterations in Preimplantation Mice Embryos Following Male Mouse Gonadal Gamma-irradiation: Comparison of Two Methods for

Background: Genome instability is a main cause of chromosomal alterations in both somatic and germ cells when exposed to environmental, physical and chemical genotoxicants. Germ cells especially spermatozoa are more vulnera-ble to suffering from DNA damaging agents during spermatogenesis and also more potent in transmitting genome instability to next generation. Methods: To investigate the effects of γ-rays on inducing abnormalities mani-fested as numerical Chromosome Aberrations (CA) and Micronucleus (MN) in preimplantation embryos, adult male NMRI mice were irradiated with 4 Gy of γ-rays. They were then mated at weekly intervals with superovulated, non-irradiated female mice in 6 successive weeks. About 68 hr post coitous, four to eight cell embryos were retrieved and fixed on slides using standard methods in order to screen for CA and MN. Results: In embryos generated from irradiated mice, the frequency of aneu-ploidy and MN increased dramatically at all post-irradiation sampling time