BACKGROUND: For many years, the world community has been concerned with the problem of the consequences of radiation exposure on the human body. A wide range of possible variants of radiation effects on humans and biota determines the range of necessary pharmacological means of protecting the organism and populations. In the mechanisms of the formation of radioresistance, the leading role is assigned to the processes of lipid peroxidation (LPO) and the antioxidant (AO) system. The study of the effect of such factors as radiation and immobilization stress on the body separately and in combination is relevant since the modern conditions of human habitation are characterized by high urbanization, physical inactivity, and a complex radioecological situation in a number of regions. AIM: The aim of the study was to study the role of free radical oxidation in the tissues of the adrenal glands and immunocompetent organs and cells under the combined effect of a sublethal dose of gamma radiation and immobilization stress in the experiment. MATERIALS AND METHODS: The work was carried out on 40 male Wistar rats: I-control; II-subjected to immobilization stress after 1 h; III-exposed to gamma irradiation; and IV-tested combined effects (immobilization stress and gamma radiation). Before the exposure, there was topometric-dosimetric preparation of the experimental animals. To this end, the object was placed on an isocentric therapeutic desk of Terasix X-ray simulator (Czech Republic), which is similar to the therapeutic desk of the γ-irradiator by its construction and parameters. RESULTS: The results obtained make it possible to assess the role of free radical oxidation under the combined action of ionizing radiation at a sublethal dose and immobilization stress in the experiment. The combined effect was accompanied by the accumulation of diene conjugates and malondialdehyde products in homogenates and the development of double oxidative stress in the test objects. The dominant role of ionizing radiation was revealed under the combined effects of immobilization stress and radiation factor. CONCLUSIONS: In animals of the 4th group, the state of oxidative-metabolic processes was characterized by overproduction of LPO products and subsequently by depression of AO defense. The urgency of continuing research on the combined effects of radiation and stress factors on public health and taking measures to eliminate negative effects on the population seems to be undoubted.
BackgroundWe studied the life history of Gagea graeca (L.) A. Terracc. (sect. Anthericoides) by field surveys on the Greek island of Crete, including quantitative analyses of 405 individuals, estimation of resource allocation by measuring the nitrogen content of different plant organs, assessing seed set and recording genetic diversity via amplified fragment length polymorphism (AFLP) analyses. In contrast to most species of the genus G. graeca seems to be a short-lived perennial, developing several characters that are rather typical for annual plants.ResultsAlthough seed set varies largely, flowering plants produce many (68 ± 79) small, flattened seeds (mean weight 73 ± 22 µg) in comparison to a single bulbil. If measured as nitrogen content of the respective plant parts, investment in seeds (25%) is much higher than that in bulbils (4%). In addition, the threshold for flower formation (expressed as bulb size where 50% of the plants form the respective structure) is with 2.17 ± 0.05 mm lower than that for bulbils with 2.80 ± 0.16 mm. This is in accordance with AFLP analyses revealing predominantly sexual reproduction (only 9.1% of 110 investigated plants belonged to clones).ConclusionIn the genus Gagea early, predominantly sexual reproduction seems to be characteristic for species from arid habitats, coupled with a low proportion of clonal plants.
We studied the combined effect of gamma radiation (6 Gy, remote period) and immobilization stress on immunological reactivity. Materials and methods. To address this, we carried out experiments on 40 white male Wistar rats weighing 220 ± 20 g, which were divided into 4 groups: Group I - intact animals, group II - animals exposed to gamma radiation (dose of 6 Gy), group III - animals exposed to immobilization stress and group IV - animals exposed to combined exposure to gamma radiation (dose of 6 Gy) and immobilization stress. Animals in groups II and IV were irradiated 90 days before the study on the TERAGAM radiotherapeutic cobalt unit. In groups III and IV, animals were modeled for acute immobilization stress by immobilization for 6 h in bright light. Results. At the early period of immobilization stress, all indicators of the immune system, such as cellular, humoral and nonspecific phagocytic links of immunity were activated, indicating the activation of the general adaptive syndrome of the organism. The suppressive action of gamma radiation on the immune system was preserved in a remote period, with this suppression being revealed not only on the T-cellular link, but also on nonspecific phagocytic links, and the functional metabolic activity of neutrophils. In the remote period after the combined effect of sublethal gamma radiation and immobilization stress in the early stage of the adaptation syndrome, there was a decrease in all cells of the T system of immunity, in the functional ability of leukocytes, and in the mononuclear phagocytic system of the body. The experimental immobilization-radiation pathological process was accompanied by disorders of the functional activity of the essential adaptive systems of the body. Based on our results, we could conclude about the dominant role of ionizing radiation in immunological reactivity. HIGHLIGHTS At an early stage, after exposure to stress, the general adaptation syndrome is activated in the body The suppressive effect of gamma radiation on the immune status and phagocytic activity persists in the long term The pathological process that occurs under the combined effects of radiation and immobilization stress is accompanied by a violation of the functional activity of the most important adaptive systems of the body Under the combined influence of radiation and non-radiation factors, the radiation factor has a predominant influence GRAPHICAL ABSTRACT
Background: Under physiological conditions, the activity of the formation of active oxygen is low. The activity of these processes is intensified under stress-induced situations. This study aimed to investigate the role of free-radical oxidation (FRO) in adrenal tissues and immunocompetent organs and cells in mature white rats after 6 hours of immobilization stress. Methods: The studies were performed on 40 White male rats of the Wistar line with a bodyweight of 200 to 240 g. Two series of experiments were conducted: I series: determination of indices in intact rats (10 rats); II series: determination of indices after a 6-hour immobilization stress action on them. Animals of II series were divided into 3 groups of 10 rats in each: group 1: those undergoing acute immobilization stress, withdrawal from the experiment in 1 hour; group 2: those undergoing acute immobilization stress, withdrawal from the experiment in 25 hours; and group 3: those undergoing acute immobilization stress, withdrawal from the experiment in 49 hours. The obtained data were processed by statistical methods with the help of the "Biostat" and "Excel" software packages. Results: In groups 1, 2, and 3, the animals were simulated acute immobilization stress by fixing the animals for 6 hours in bright light. The results of the conducted studies indicate changes in lipid peroxidation and antioxidant system (LPO-AOS) in case of immobilization stress-excitation. In developing free-radical pathology at immobilization stress-excitation, the more expressed disturbance of LPO-AOS, and accordingly the intensity of lipoperoxidation in the structural membrane of all investigated organs was high at the initial stage of exposure. Conclusion: At 49 hours after immobilization, stress less pronounced influence on the lipoperoxidation process was noted. The increase in the intensity of excessive lipoperoxidation testifies to the inhibited manifestation of AOS in the organism.
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