Induction of chromosomal instability in mouse hemopoietic cells by fetal irradiation.

Mice were exposed to 0.25-1.5Gy of gamma radiation on day 14 or 17 of gestation and chromosomal aberrations were scored in the bone marrow at 12 months of age. Irradiation had resulted in low peripheral blood counts, while some animals developed very high leukocyte counts. Exposed animals showed a significant dose dependent increase in the number of aberrant metaphases, compared to unexposed animals. Fragments and polyploidy were the major types of aberrations. Mice with abnormally high blood leukocyte counts showed a higher incidence of chromosomal aberrations, especially high levels of polyploidy than in animals with low blood counts. It is concluded that radiation induced genomic instability in the fetal hemopoietic cells of mouse is transmitted to postnatal and adult bone marrow which may lead to the development of hematological disorders, including malignancies.