Radiation damage to femoral hemopoietic stroma measured by implant regeneration and quantitation of fibroblastic progenitors.

Radiation damage to femoral hemopoietic stroma in mice was measured 6 weeks after irradiation and reconstitution with syngeneic bone marrow by quantitation of fibroblastic progenitor cells (CFUF), and by assaying hemopoietic progenitors and CFUF numbers in regenerated subcutaneous femur implants. A dose-dependent effect of radiation on both preimplantation CFUF numbers and implant regeneration was observed. Changes in bone marrow cell (BMC) graft size did not alter these stromal parameters. Therefore, transplanted CFUF, which were present in the BMC graft, did not alter either the CFUF content of femurs or their regenerative capacity. The strong correlation between CFUF numbers and implant regenerative capacity after irradiation, leads us to suggest a function for CFUF in femoral implant stromal regeneration.