[Comparative protective action of radiorotectors and shielding in gamma-irradiated mice]

Experiments with male mice were performed to evaluate comparative effectiveness of radioprotectors cystamine, aminoethyl isothiuronium, mexamine and indralin against minimal absolutely lethal gamma-doses (9 Gy). The best protective effect was demonstrated by indralin at a dose of 75 mg/kg. Supportive data were received in experiments with rats. The radioprotective action of indralin consists mainly in quite successful preservation of the blood-forming components, i.e. the pool of stem cells in the marrow and spleen. Gamma-irradiation at superlethal doses (10 Gy and higher) weakens significantly or fully neutralizes these protectors in rodents. Shielding of radiosensitive organs with the help of lead and plastics proved to be a good protection of animals from minimal lethal gamma-doses. However, the superlethal doses of gamma-irradiation penetrated the shielding materials and disabled them to a large and full extent. Evaluation of effectiveness of the combined protection against superlethal gamma-doses by pharmaceutical agents and shielding revealed a potentiating effect. For instance, mexamine and shielding of the abdomen together increased survivability of rats to 76.7%. An even stronger effect was noted when shielding was combined with indraline which raised survivability to 100%. It should be emphasized that this combination is effective against superlethal gamma-doses that usually unassailable to radioprotectors and shielding.