Abstract
Radioadaptive response (AR) is a complex interplay between the irradiations and the organisms with the surrounding conditions involved. Genetic background is one of the crucial factors among the prerequisite conditions essential to the successful AR induction. As genetic diversity plays important roles in survival and adaptability of a species, laboratory mice provide good animal models for studying the differences among individuals in humans. On induction of AR, in vivo studies show clearly strain-specific differences in adult mice and in utero investigations demonstrate different efficient priming doses in fetal mice of different strains. For possible practical application of AR in tailor-made therapy, it is an approach to elucidate the similarity and dissimilarity of molecular mechanisms in different strains by comparing gene regulations under conditions efficient and inefficient in AR induction and correlating their functions with AR phenotype. As the first step, in this study AR induction in utero was tested in several strains of fetal mice using prenatal death, gross malformation and prenatal developmental retardation as the indexes. Two priming doses of X-irradiations efficient in C57BL strain were adopted and applied to the pure fetal mice of the C3H strain and BALB/c strain, and the hybrid fetal mice of mixed parentage from such as female C57BL and male C3H mice, female C3H and male C57BL mice and other combinations. Being different from the ICR and C57BL strains, AR was not observable in C3H and BALB/c strains. Interestingly, the hybrid fetal mice showed varied responses to these priming doses. These findings indicate the strain-specific differences in AR induction in fetal mice.
