Radioprotection of hemopoiesis conferred by aqueous extract from chlorococcal algae (Ivastimul) administered to mice before irradiation.

In experiments on mice, single i.p. injections of aqueous extract from chlorococcal freshwater algae (Ivastimul) were found to increase their radioresistance. During the same period the number of spleen colony-forming units (CFUs) in the bone marrow and spleen and their proliferation activity increased. The amount of granulocyte-macrophage colony-forming cells (GM-CFC) in the bone marrow grows and the colony-stimulating activity (CSA) of the blood serum of mice is elevated at an early period after injection of the substance. The recovery of the CFUs and GM-CFC pools in femoral bone marrow after irradiation proceeds at a faster rate in Ivastimul-treated animals than in control groups. The activation of the pool of hemopoietic stem cells and stimulatory effects of Ivastimul on granulocytopoiesis act favorably on the repair of radiation damage and on increased percentage of animals surviving lethal doses of gamma radiation.