Outbred CD-1 mice females aged 4 to 4.5-months were investigated in 21-22 hours following total γ-irradiation at 10, 25, 50, 75, 100 and 200 mGy. Loss in bone marrow karyocytes, as well as spleen and thymus mass reductions were significant in the group of animals irradiated at 50 and 200 mGy and less dramatic in mice irradiated at 75 mGy. The orientative-trying behavior reaction (OTBR) in the open field tested in 19-20 hours after exposure to 10 and 25 mGy was reliably stronger than in the group of biological control; however, emotional status (ES) in the animals that received 10 mGy dropped significantly. Mice irradiated at 50 mGy were found to weaken the grip of their front limbs. Dose levels differing in opposite radiobiological effects on the parameters under study were established. Doses in the range from 10 to 25 mGy maximized OTBR and ES, while doses of 50, 100 and 200 mGy produced high reactions of the immune and hemopoietic organs.

The experiment was performed with outbred ICR (CD-1). female mice (SPF). The animals were irradiated by 171 MeV protons at a dose of 20 cGy. The spacecraft radiation protection elements used in the experiment were a construction of wet hygiene wipes called a "protective blind", and a glass plate imitating an ISS window. Physical obstacles on the path of 171 MeV protons increase their linear energy transfer leading to the absorbed dose elevation and strengthening of the radiobiological effect. In the experiment, two types of obstacles together raised the absorbed dose from 20 to 23.2 cGy. Chemically different materials (glass and water in the wipes) were found to exert unequal modifying effects on physical and biological parameters of the proton-irradiated mice. There was a distinct dose-dependent reduction of bone marrow cellularity within the dose range from 20 cGy to 23.2 cGy in 24 hours after exposure. No modifying effect of the radiation protection elements on spontaneous motor activity was discovered when compared with entrance protons. The group of animals protected by the glass plate exhibited normal orientative-trying reactions and weakened grip with the forelimbs. Rationalization of physical methods of spacecrew protection should be based as on knowledge in physical dosimetry (ionizing chambers, thermoluminescent, track detectors etc.), so the radiobiological criteria established in experiments with animals.

The eye retina consists of terminally differentiated cells that have lost their ability to proliferate. The death of these cells leads tothe loss of sight. The mice retina is characterized by relatively high resistance to radiation, which is provided by its ability to repair damage caused by environmental factors. The aim of our work was to assess the damaging effect of ionizing radiation and methylnitrosourea (MNU) on the DNA structure in the mouse retina, the functional activity of the retina, and its ability to recover in vivo. The results confirm the ability of the mature retina to structural and functional recovery. Adapting influence of low dose chemical agent increases retina resistance to cytotoxic dose of genotoxicants and prevents degeneration of photoreceptor layer of the retina. The results show the possibility of neurohormesis effect in the mice retina after exposure to ionizing radiation and chemicals.

Сетчатка глаза состоит из терминально дифференцированных клеток, утративших способность к делению. Гибель этих клеток приводит к утрате зрения. Сетчатка мышей характеризуется сравнительно высокой устойчивостью к радиации. Эта устойчивость сетчатки обеспечивается ее способностью к восстановлению от повреждений, вызываемых факторами внешней среды. Цель работы заключалась в оценке повреждающего действия ионизирующего излучения и метилнитрозомочевины (МНМ) на структуру ДНК в сетчатке глаза мышей, функциональную активность сетчатки и в оценке ее способности к восстановлению in vivo. Результаты подтверждают способность зрелой сетчатки к структурному и функциональному восстановлению. Адаптирующее воздействие в малой дозе химического агента повышает устойчивость сетчатки к цитотоксической дозе этого генотоксиканта и препятствует дегенерации фоторецепторного слоя сетчатки. Полученные результаты указывают на возможность эффекта нейрогормезиса в сетчатке глаза мышей при действии ионизирующей радиации и химических веществ.