Abstract
Following exposure of p53 (-/-) and p53 (+/+) mice to 0.5 or 1 Gy of X-rays, micronucleus (MN) frequency was measured in the reticulocytes sampled at multiple time points after exposure. In either strain of mice, MN frequency increased over the spontaneous level as the time elapsed after exposure to a peak at 24 h and then decreased time-dependently to the spontaneous level at 120 h after exposure, irrespective of the dose used; the frequency averaged for the sampling times from 12 to 96 h, F (%), followed a linear equation of F=a+bD, where a is spontaneous MN frequency (%), b induced rate of MNs (% Gy−1) and D dose (Gy). Experimentally obtained a values for p53 (-/-) and p53 (+/+) mice are 0.24±0.04 and 0.71±0.08, respectively; the b values are 1.1±0.1 and 2.3±0.3, respectively. These results suggest that normal p53-gene function is involved in apoptotic elimination of DNA damage induced, either spontaneously or after radiation, in erythroblasts of mice. [J Radiat Res 44:449 (2003)]
