[Effect of hydroxyurea on the number of hematopoietic stem cells, stromal cell precursors and cell precursors of thymus lymphoid tissue in the bone marrow of mice during aging].

The concentration of hemopoietic stem cells (colony-forming cells in the spleen - CFC-S) decreases in the bone marrow of CBA mice during ageing, whereas the concentration of precursors for stromal fibroblasts (colony-forming cells for fibroblasts-CFC-F) increases. The total numbers of nucleated cells, CFC-S and CFC-F in the bone marrow of old mice essentially increase. Hydroxyurea, administered in vivo, does not effect the concentration of CFC-S, but it increases CFC-F concentration in the bone marrow of mice. Hydroxyurea produces just the same suppressive effect on the numbers of nucleated cells, CFC-S and CFC-F in the mice of different ages, and stimulates the capacity of bone marrow donors to repopulate the thymus of the irradiated young recipients.