Age-related changes in various hemopoietic progenitor cells in senescence-accelerated (SAM-P) mice.

The effect of aging process on the hemopoietic system in senescence-accelerated (SAM-P) mice with respect to numbers of hemopoietic progenitor cells was investigated. The numbers of femoral granulocyte-macrophage colony-forming cells (CFU-GM), mast cell progenitors (mast colony-forming units, CFU-Mast), erythroid burst-forming units (BFU-E), and erythroid colony-forming units (CFU-E) in old mice (30-35 weeks old) decreased to 96%, 81%, 83%, and 87% of those of young mice (8-12 weeks old), respectively. The numbers of femoral fibroblast colony-forming cells (CFU-F) in old mice increased to 315% of those of young mice. The numbers of splenic CFU-GM, CFU-Mast, BFU-E, and CFU-E in old mice decreased to 7%, 43%, 25%, and 40% of those of young mice, respectively. In contrast, significant changes in these progenitor cells were not observed in the bone marrow. These findings suggest that the effect of the aging process on hemopoietic tissues in SAM-P mice is predominantly in the spleen.