Accelerated recovery of hematopoiesis following sub-lethal whole body irradiation with recombinant murine interleukin-1 (IL-1).

This communication reports the results of studies designed to investigate the ability of recombinant murine interleukin-1 (rIL-1) to enhance the recovery of hematopoiesis following administration of sub-lethal whole body irradiation (2 Gy). Mice were administered rIL-1 (100 and 500 units) i.p. Twenty-four hours later these mice were administered 2 Gy radiation. Irradiated control mice were given only phosphate buffered saline (PBS). Animals were then serially sacrificed (on days 1, 2, 4, 7, 9, and 12 following irradiation) and their peripheral blood was analyzed for indices (packed red cell volume, WBC, platelets, and differential). Femoral bone marrow was harvested and assayed for their stem cell content--erythroid (CFU-E, BFU-E), granulocyte-macrophage (CFU-GM), and megakaryocyte (CFU-MEG). Irradiated mice pretreated with rIL-1 demonstrated accelerated hematopoietic recovery as measured by higher WBC, platelets and femoral stem cell content than PBS-treated irradiated controls. These results indicate IL-1 may be an effective radioprotective agent against the hematotoxicity induced by ionizing radiation.