Differential sensitivity of two predominant stromal progenitor cell subpopulations in bone marrow to single and fractionated radiation doses.
The sensitivity of fibroblastoid precursor cells in rat bone marrow to single and fractionated doses of gamma rays delivered in vivo was measured. In vitro colonies were classified as being compact or diffuse, and the progenitor cells for both types were slowly cycling in vivo (survival levels after exposure to hydroxyurea were 90 +/- 6% and 93 +/- 11%, respectively). The progenitor cells forming diffuse colonies were more resistant (D0 = 1.39 Gy) than those forming compact colonies (D0 = 0.76 Gy). The fractionation sensitivities were characterized by an alpha/beta ratio of 12.7 +/- 5.5 Gy for diffuse colonies and 4.5 +/- 3.0 Gy for compact colonies, respectively. The progenitor cells forming diffuse colonies may contribute more to long-term regeneration after high doses in vivo.
D000818:Animals; D001853:Bone Marrow / Q000528:radiation effects*; D001854:Bone Marrow Cells; D002453:Cell Cycle / Q000187:drug effects / Q000528:radiation effects; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D002478:Cells, Cultured; D003114:Colony-Forming Units Assay; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000187:drug effects / Q000528:radiation effects; D006918:Hydroxyurea / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects / Q000528:radiation effects*; D017154:Stromal Cells / Q000166:cytology / Q000187:drug effects / Q000528:radiation effects*; D014916:Whole-Body Irradiation
D006918:Hydroxyurea