title: Protective effect of a mixture of radioprotective substances (AET and mexamine) on the haemopoietic stem cells of mice.
abstract: A protective effect of a combined application of radioprotectors (AET -i.p., mexamine -s.c.) was studied in experiments on mice. Duration of the protective effect on the haemopoietic stem cells and on the survival of mice after a lethal exposure to X-ray radiation lasted for 5 hours after the injection. DRF calculated from a change of LD 50/30 reached the maximum (1.53) within 30 min after the injection, and was equal to 1.17 within an interval of 5 hrs. The protection of haemopoiesis, as expressed by DRF calculated from an equieffective exposure for 2 ESC, reached the maximum within a 60 min interval after the injection (DRF=3.4). D0 calculated from the CFU survival curves of endogenous haemopoietic tissue colonies (ESC) was, within a 120 min interval, almost three times higher (310 R) than in the control group (110 R). After the injection of radioprotectors a greater number of haemopoietic CFU survives at an exposure of 100-400 R than after mere irradiation. The postirradiation decrease in the weight of small intestine was smaller in protected animals than in the controls. The role of a decrease of the radiation damage to the haemopoietic stem cells in the total protective effect of the radioprotectors used is discussed.
mesh_terms: D000818:Animals; D006412:Hematopoietic Stem Cells / Q000187:drug effects* / Q000528:radiation effects; D007928:Lethal Dose 50; D008738:Methyl Ethers / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D011837:Radiation-Protective Agents; D013997:Time Factors; D014363:Tryptamines / Q000494:pharmacology*; D014965:X-Rays; D000338:beta-Aminoethyl Isothiourea / Q000494:pharmacology*
chemical_list: D008738:Methyl Ethers; D011837:Radiation-Protective Agents; D014363:Tryptamines; D000338:beta-Aminoethyl Isothiourea