effect of vitamin e on preovulatory stage irradiated female mouse expressed as chromosomal abnormalities in generated embryos

background: the present study has been carried out to investigate the effects of preovulatory stage gamma-irradiation of female mice in the absence or presence of vitamin e on numerical chromosome abnormalities in 8-cell embryos after mating with non-irradiated males. materials and methods: the 8-11 weeks adult female nmri mice were whole body irradiated at preovulatory stage (post pmsg injection and about 12-18 hours before injecting hcg) with 4 gy gamma-rays generated from a cobalt-60 source alone or in combination with 200 iu/kg vitamin e, intrapretoneally administered one hour prior to irradiation. soon after hcg injection super ovulated irradiated females were mated with non-irradiated males. about 68-h post coitous (p.c), 8-cell embryos were flushed from the oviducts of pregnant mice and were fixed on slides using standard methods in order to screen for metaphase spreads and numerical chromosome abnormalities. results: in control embryos, 8% of metaphase plates were aneuploid, whereas in preovulatory stage irradiated female mice, about 50% of metaphase plates of embryos showed numerical chromosome aberrations ( p<0.001 ). administration of vitamin e one hour before the irradiation reduced chromosomal aberrations significantly (p=0.005). conclusion: results show that the effects of gamma-irradiation on preovulatory stage oocytes led to chromosomal abnormalities in subsequent embryos generated by these oocytes. increase the frequency of numerical chromosome abnormalities -mostly aneuploidy- may be due to abnormal chromosomal non disjunctions during 2nd meiotic division. reduction of the frequency of chromosome aberrations in the presence of vitamin e is probably due to antioxidant effects of this vitamin, and scavenging free radicals induced by gamma-rays in mice oocytes’ environment.