In vivo chromosomal instability and transmissible aberrations in the progeny of haemopoietic stem cells induced by high- and low-LET radiations

Abstract

Purpose : To study stable and unstable chromosomal aberrations in the haemopoietic cells of CBA/H mice after exposure to both high- and low-LET radiations. Materials and methods : Chromosomal aberrations were scored in the clonal progeny of X-, α - or non-irradiated short-term repopulating stem cells using the spleen colony-forming unit (CFU-S) assay, 12 days post-transplantation and in the bone marrow reconstituted by X-, neutron- or non-irradiated exogenous (transplanted) or endogenous (X- or neutron whole-body-irradiated) long-term repopulating stem cells for up to 24 months. Results : Chromosomal instability was demonstrated in 3-6% of cells in all cases. After transplantation of X- or neutron-irradiated bone marrow ~8% of cells with stable aberrations were recorded at all times. After 3 Gy X- or 0.5Gy neutron- whole-body irradiation stable aberrations were detected in ~17 and 5% of cells respectively. Conclusions : Chromosomal instability induced in vitro can be transmitted in vivo by transplantation of haemopoietic stem cells exposed to high- or low-LET radiations. Comparable instability can be induced and shown to persist for the remaining lifetime after whole-body irradiation. There was no direct relationship between the expression of stable and unstable aberrations and significant interanimal variation in the expression of both stable and unstable aberrations.