Induction and persistence of cytogenetic damage in mouse splenocytes following whole-body X-irradiation analysed by fluorescence in situ hybridization. I. Dicentrics and translocations

Chromosome translocations (stable aberrations) can persist longer during cellular proliferation than dicentrics (unstable aberrations). It is important to know the kinetics of the elimination of dicentrics and to what extent translocations persist in an in vivo cell population after irradiation. The female Swiss mouse were used to study the induction and persistence of dicentrics and translocations in splenocytes up to 112 days after exposure to 2Gy whole-body X-irradiation. Metaphase spreads at different time intervals were analyzed by fluorescence in situ hybridization (FISH) using chromosome-specific DNA libraries for chromosomes 1, 11 and 13. The frequencies of dicentrics and translocations appear to be equal immediately after irradiation. Frequencies of dicentrics decreased exponentially with time according to the relationship D=ae-kt. The rate of elimination was faster in the early period (days 0-14) than in the later period (14 days). The frequency of translocations was constant in the period 0-7 d...