Chromosome Aberrations do not Persist in the Lymphocytes or Bone Marrow Cells of Mice Irradiated In Utero or Soon after Birth

Abstract Nakano, M., Kodama, Y., Ohtaki, K., Nakashima, E., Niwa, O., Toyoshima, M. and Nakamura, N. Chromosome Aberrations do not Persist in the Lymphocytes or Bone Marrow Cells of Mice Irradiated In Utero or Soon after Birth. Radiat. Res. 167, 693–702 (2007). Mice were exposed at various ages to 1 Gy or 2 Gy of X rays, and translocation frequencies in peripheral blood T cells, spleen cells, and bone marrow cells were determined with FISH painting of chromosomes 1 and 3 when the animals were 20 weeks old. It was found that the mean translocation frequencies were very low (≤0.8%) in mice exposed in the fetal or early postnatal stages. However, with the increase in animal age at the time of irradiation, the frequency observed at 20 weeks old became progressively higher then reached a plateau (about 5%) when mice were irradiated when ≥6 weeks old. A major role of p53 (Trp53)-dependent apoptosis for elimination of aberrant cells was not suggested because irradiated fetuses, regardless of the p53 gene status,...