Radiosensitivity of Progenitor Cells of the Hematopoietic Microenvironment

Publisher Website
Google Scholar
Abstract
The radiosensitivity of cells which transfer hematopoietic microenvironment was studied in a model by transplanting femoral bone marrow under the renal capsule of a mouse. For in vitro 137Cs .gamma.-irradiation, the mean dose [Do] for the hematopoietic microenvironment transferring units (HMTU) was 444 .+-. 5 rad and the extrapolation number (n) was 5.2. The value of the quasi-threshold dose (Dq) was .apprx. 500 rad which reflects the high capacity of HMTU for repair of sublethal injury. After in vivo exposure to .gamma. rays, HMTU radiosensitivity was somewhat higher (Do of 325 .+-. 25 rad, n of 3.5 and Dq of 635 rad). For in vitro irradiation with fast neutrons, the Do was 161 .+-. 19 rad and n, 1.4. Based on the fraction of transplant failures after exposure to different radiation doses, it was calculated that 1 femoral marrow plug contains .apprx. 50 HMTU.