The influence of the novel drug Ukrain on hemo- and immunopoiesis at the time of its maximum radioprotective effect.

Several studies have demonstrated that when Ukrain, a complex preparation of great celandine alkaloids, is used as a preventive agent it increases the survival of animals exposed to whole body gamma-irradiation and enhances the restoration of hemopoiesis. The aim of this study was to describe qualitative and quantitative changes in hemopoietic precursor cells and in myelokaryocytes and leukocytes in the blood caused by Ukrain from its administration to the time the maximal radioresistance potential of the organism is reached. Ukrain was administered i.p. at the dose of 0.2 mg/kg, 24 h prior to investigation. Control animals were injected with saline. Colony-forming units (CFU) were counted in the spleen and bone marrow of the mice, and myelokaryocyte and leukocyte (lymphocyte and granulocyte) counts were determined. The results of this study suggest that Ukrain causes qualitative and quantitative alterations in different pools of hemopoietic cells (stem cells, proliferating cells, maturing cells, and competent cells). These alterations affect the size of the stem cell pool, the kinetics of stem cell proliferation, the direction of their differentiation pathways, the rate of circulation of stem cells and precursor cells, the efficiency of recolonization of cell-depleted sites, and other parameters, which in effect modify standard responses of hemopoiesis and immunogenesis to irradiation so that the radioresistance of the whole organism increases.