Purpose: Assessing the role of various factors in the formation of radioresistance is an important branch of radiobiology. The quality of drinking water, as it turned out, can significantly affect radioresistance. Against the background of studying the antiradiation properties of various types of water, differing in mineral and isotopic composition, the problem of the influence of tap water on the course of radiation injury remained underestimated. This circumstance determined the purpose of the work: to evaluate the modifying effect of tap water on the course of acute radiation sickness after X-ray irradiation of mice at an average lethal dose. Material and methods: Female ICR (CD-1) mice were irradiated with an average lethal dose once – 6.5 Gy of X-ray irradiation. After irradiation, half of the mice received tap water as drinking water, and the other half received artificially mineralized drinking water. Results: Keeping animals on tap water significantly reduced the survival rate of mice both with a single dose (log-rank test p=0.02, χ2=5.38) compared with animals receiving artificially mineralized distilled water. In addition, in the group of mice that received tap water, an increase in the rate of death of mice and a lower preservation of the group mass of animals during the development of acute radiation injury was noted. Conclusion: Tap water, used as drinking water, increases the damaging effect of radiation when X-rays are irradiated in mice.

Purpose: To clarify the frequency, nosological forms, the timing of development and the features of the clinical course of developed oncohematological diseases on the basis of a retrospective analysis of the results of long-term follow-up of patients who underwent acute radiation syndrome (ARS). Material and methods: An analysis of clinical histories from archives of A.I. Burnasyan Federal Medical Biophysical Center of 157 patients who underwent ARS of varying severity, and some scientific publications. Various oncohematological diseases developed in the long-term period in 8 patients with ARS I–III severity: in 5 patients – myelodysplastic syndromes (MDS), in 2 – chronic myeloid leukemia (CML) and in 1 – acute myelomonoblastic leukemia (OMML). Results: The excess absolute risk of developing MDS and leukemia in the group is 7.2×10–4 man-years/Gy. All patients underwent relatively uniform irradiation. MDS developed in 5 patients who underwent ARS as a result of a single acute gamma-beta- and gamma-neutron irradiation at doses of 1.2–5.0 Gy. Nosological forms of MDS: with unilinear dysplasia, with multilinear dysplasia (2 cases), with ringed sideroblasts, with excess blasts. The latency period lasted from 3 to 31 years. Age at the time of irradiation was 28–55 years. CML, Ph-positive form, was detected in 2 patients. Doses of gamma-beta-radiation were 2.0 and 4.3 Gy. Age of patients at the time of irradiation was 22 and 25 years. Diseases developed 3 and 15 years after the undergone ARS and were characterized by a long period of inactive phase (10 and 7 years), which resulted in a blast crisis. OMML in the patient, who suffered during the Chernobyl accident and since 1990 was observed in the URCRM, developed 11.8 years after irradiation at a dose of 3.0 Gy. An analysis of available clinical data makes it possible to question the diagnosis of acute leukemia, and to suppose that chronic myelomonocytic leukemia developed in this patient. Conclusion: The obtained data indicate that chronic leukemia forms are characteristic for radiation leukemia, often with a long preceding cytopenic stage (MDS). An essential factor in the realization of the leukemogenic effect is the uniformity of the whole body exposure undoubtedly. In addition, it can’t be ruled out that the carriage of hepatitis B and C viruses also played a role in the formation of MDS.

The products of radiolysis released from cellular compartment under the influence of ionizing radiation: highly mobile groups of proteins, damaged nuclear and mitochondrial DNA, extracellular ATP and oxidized low density lipoproteins, cause stress activation in irradiated tissues through a pattern of the receptors with start of the cascade r53 and NF-κB of pro-inflammatory ways conducting to an expression of pro-inflammatory genes stimulating synthesis of cytokines of the IL-1 family. Excessive activation of pro-inflammatory way under the influence of a radioactive stress is limited to synthesis, anti-inflammatory cytokines: IL-4, IL-10, IL-11, IL-13 and also antagonists of IL-1 receptor and TGF-β. G-CSF and MG-CSF induced by action of pro-inflammatory cytokines have anti-inflammatory and anti-apoptotic properties decreasing level of pro-inflammatory cytokines IL-6 and TNF. Glucocorticoids participate in regulation of primary radioactive stress, suppressing an excessive expression of genes of pro-inflammatory cytokines. Increased IL-1 level stimulates secretion of corticosteroids through mechanism of feedback. Adrenergic stimulation is capable to raise a gene IL-1β expression. The mechanism of radiation apoptosis of stem cells is implemented through p53-Puma way which blocks interaction anti-apoptotic proteins of Bcl-2 with pro-apoptotic proteins of Bax and Bak. After release from mitochondrion of cytochrome C and apoptosis-inducing factor there is an activation of effector caspases: caspases 3, 6 and 7 through caspase 9, and final cell destruction. Wnt way is crucial for post-radiation repair. Potential of the regenerative response of hemopoietic tissue to radiation injury depends on catenin and ability of Wnt way to stimulate post-radiation bone marrow reparation. Mesenchymal stem cells of bone marrow play a large role in post-radiation regeneration of hemopoietic tissue. Their main action is carried out through TLR2 and TLR4 receptors. Mobilization of hemopoietic stem cells is bound to release proteases from bone marrow, including neutrophil elastase and cathepsin G, and a matrix metalproteinase-9. Radioprotective properties of exogenous IL-1 aren’t limited only by induction of raised G-CSF and GM-CSF production. The larger role in radiation protection is played by the reaction induced by IL-1 in the form of feedback with production anti-apoptotic and anti-inflammatory factors. Primary radioactive stress limits time of radiomitigable effect of IL-1 by 1-2 h after its application after radiation.

Purpose: A synthetic study of published data on the growth and development of laboratory rats (albino random-bred, Wistar and Long–Evans) depending on the period of their breeding since 1906 was carried out. Material and methods: Data for the dynamics of growth and age periods of rats were used for calculations and general analysis. Results: Acceleration in terms of age–weight indices for strain animals was found: in conditions of complete diets ad libitum the contemporary rats grew several times faster than the bred ones of 1906–1932. For random-bred rats only the tendency to acceleration was obtained. For more than a century, the Wistar males showed an inverse linear correlation between the breeding year and the age (in weeks) at the of the onset of puberty period (according to the Spearman test: r = –0.952; p = 0.00026; Pearson’s criterion: r = –0.950, p = 0.0003). There was also a direct correlation between the body mass of rats at the time of puberty onset and the year of their breeding (according to the Spearman test: r = 0.975; p = 0.005; Pearson criterion: r = 0.927; p = 0.023). The possible reasons for the acceleration of laboratory growth of rats, which are unlikely to be analogous to the factors presumably causing the known ‘growth acceleration’ in humans (changes in natural and artificial lighting, the effect of heterosis, improvement of socio-hygienic conditions, the growth of information flow, warming of the climate, change in the geomagnetic or radiation background, etc.) were discussed. Apparently, in addition to the probability of special and/or subconscious selection during century, the stimulation of rat acceleration may be explained by the ‘increase in living space and resources’ due to improved standards for keeping animals in the modern period (fewer animals in the cage or even an individual cage). In random-bred animals such standards can be apply for economic reasons to a lesser extent. Conclusions: It is concluded that the physiological, anatomical, possibly behavioral and other standards and patterns for strain rats, including, possibly, its radiosensitivity, published even 30 years ago, and especially more than 50 years ago, should be cautiously transferred to the animals grown under present-day conditions.