Effects of chemotherapeutic agents on hemopoietic stromal tissue: I. Effects of cyclophosphamide and bleomycin on hemopoiesis in subcutaneous femur implants.

To evaluate the effect of bleomycin and cyclophosphamide on the hemopoietic support capacity of marrow tissue, femurs were excised from mice at various times after treatment with one of these agents and implanted subcutaneously for up to 12 weeks. The cellularity, histologic appearance, hemopoietic progenitor cell contents, reticuloendothelial cell function (99mTc-sulfur colloid incorporation) and colony-stimulating activity (CSA) production of these femurs were evaluated. The results suggest that cyclophosphamide does suppress the capacity of implanted femurs to support normal hemopoietic precursor cell population for up to 13 weeks after cessation of treatment; bleomycin has no such adverse effects. The defect produced by cyclophosphamide is not mirrored in the histologic appearance of the subcutaneously regenerating femurs. Neither 99mTc-sulfur colloid incorporation nor CSA production of femurs was suppressed by drug treatment.