[Changes in the age structure of the hematopoietic stem cells of older mice under the influence of a factor inhibiting their proliferative activity].

The effect of stem cell proliferation inhibitor (PIF) on hemopoietic stem cell and committed precursor cell subpopulations in aged mice was studied. The following parameters were analyzed: the number of CFUs-5, CFUs-8, and CFUs-12 in bone marrow and spleen, the number of BFUe, CFUs-GM, CFUs-M, and the ability of bone marrow cells of aged mice to repopulate bone marrow of lethally irradiated recipients (MRA). Characteristic of aged mice were an increased number of precursors (mainly in bone marrow), changes in their erythropoietic differentiation, and a decreased MRA of bone marrow cells. The suppression of stem cell proliferation by PIF was accompanied by a decrease in the total number of precursors and led to changes in their migration and differentiation, which might provide for restoration of hemopoiesis in aged mice to the level characteristic of young mice.