Response of Hematopoietic Stem and Progenitor Cells to Reserpine in C57Bl/6 Mice.

We studied the response of hematopoietic stem cells and progenitor cells to sympatholytic reserpine in intact C57Bl/6 mice and in animals with cyclophosphamide-induced leukopenia. The count of long-term hematopoietic stem cells (Lin(-)Sca-1(+)c-kit(+)CD34(-)) in the bone marrow of healthy mice increased in 7 min after reserpine injection and remained elevated in 2 h in parallel with elevated content of short-term stem (Lin(-)Sca-1(+)c-kit(+)CD34(+)) and progenitor (Lin(-)Sca-1(+)c-kit(+)) cells. Reserpine produced no effect on recruitment of hematopoietic stem and progenitor cells into the peripheral blood, but increased the serum level of granulocyte CSF and increased the count of metamyelocytes and neutrophilic granulocytes in the blood (in 2 h postinjection). Transplantation of bone marrow hematopoietic stem and progenitor cells from reserpine-treated donor C57Bl/6 mice to recipient CBA mice with 5-fluorouracil-induced leukopenia accelerated regeneration of the granulocytic lineage cells in leukemic mice. In cyclophosphamide-treated C57Bl/6 mice, reserpine reduced the level of short-term hematopoietic stem cells and increased the count of progenitor hematopoietic cells in the bone marrow in parallel with recruitment of the progenitors into the peripheral blood.