The study of mechanisms of radioprotective action of indometofen n hematopoietic stem cells in mouse long-term bone marrow cultures

The influence of indometophen (an analog of tamoxiphen) on the dynamic content and the proliferative activity of CFUs (colony-forming units) and CFU-GM (granulocyto-macrophages precursors) and the level of colony-stimulating factor (GM-CSF) in mouse long-term bone marrow cultures were studied for 4 weeks after administration. Five days after indometophen injection the long-term cultures were exposed to irradiation with a dose of 2 Gy and on the time course of postirradiation recovery haemopoietic precursors cells and dynamic release of GM-CSF in the culture supernatants were examined. The data of this report suggest that the mechanisms responsible for the radioprotective action of indometophen may be associated both with its direct effects on the proliferation and differentiation of hemopoietic cellular precursors and with the stimulation of release of growth-differential factors by hemopoietic microenvironmental elements.