EFFECT OF RECOMBINANT MOUSE INTERLEUKIN-3 ON HEMATOPOIESIS IN NORMAL AND CYCLOPHOSPHAMIDE-TREATED MICE

Intraperitoneal injection of recombinant mouse IL-3 in normal mice for 6 days did not induce any significant changes in leukocyte and neutrophil counts. In comparison with saline controls, IL-3-treated mice experienced a 1.7-fold increase of bone marrow nucleated cells and 3.6-fold increase of CFU-GM colonies. Tritium thymidine incorporation of bone marrow cells significantly increased in IL-3-treated mice as compared with that in normal saline-treated mice. These results suggested that IL-3 expanded the number of granulocyte-macrophage progenitor cells but not the peripheral neutrophils. We examined the effect of IL-3 on hematopoietic reconstitution in a cyclophosphamide-treated mouse model. We found that the absolute neutrophil number of mice treated with IL-3 increased significantly on day 6 post injection when compared with the control mice (6.2± 4.1×109 / L versus 0.98± 1.4 × 109/ L, P【0.01) . The results demonstrated that IL-3 stimulated an early recovery of neutrophils after

Intraperitoneal injection of recombinant mouse IL-3 in normal mice for 6 days did not induce any significant changes in leukocyte and neutrophil counts. In comparison with saline controls, IL-3-treated mice experienced a 1.7-fold increase of bone marrow nucleated cells and 3.6-fold increase of CFU-GM colonies. Tritium thymidine incorporation of bone marrow cells significantly increased in IL-3-treated mice as compared with that in normal saline-treated mice. These results suggested that IL-3 expanded the number of granulocyte-macrophage progenitor cells but not the peripheral neutrophils. We examined the effect of IL-3 on hematopoietic reconstitution in a cyclophosphamide-treated mouse model. We found that the absolute neutrophil number of mice treated with IL-3 increased significantly on day 6 post injection when compared with the control mice (6.2± 4.1×109 / L versus 0.98± 1.4 × 109/ L, P<0.01) . The results demonstrated that IL-3 stimulated an early recovery of neutrophils after cyclophosphamide-induced myelosuppression.