Target. Analysis of changes in the morphological characteristics of neurons in such phylogenetically different parts of the rat cerebral cortex in different periods after total cerebral ischemia. Methodology. Experiments were performed on 42 male outbred white rats with an initial weight of 240±20 g. Total cerebral ischemia in outbred white rats was modeled by decapitation. The material was taken at the 1st, 5th, 15th, 30th, and 60th minutes, as well as 5 and 24 hours after decapitation. Results. With total cerebral ischemia, a significant decrease in the size of neurons and deformation of the perikarya were observed. Normochromic neurons completely disappeared at the 60th minute. The number of hyperchromic neurons increased and then progressively decreased. Shriveled neurons accounted for the majority of cells in the studied areas of the cortex at 30-60 minutes, and then, after 5 and 24 hours, cells with pericellular edema predominated in the neuron population. Conclusion. The obtained data on histological changes in neurons of phylogenetically different parts of the cerebral cortex in the dynamics of total cerebral ischemia provide the basis for further detailed study of post-mortem changes in the brain, determining the time of death, creating a fundamental basis for studying the properties of neurons, including their transition from one functional state to other.

The relevance of the work is due to the wide spread of cerebrovascular pathology and ischemic strokes among the population. Most studies are devoted to the study of early brain damage in cerebral ischemia, while insufficient attention has been paid to the mechanisms of adaptation and long-term brain disorders. At the same time, delayed death of nerve cells in ischemia is not a predetermined and irreversible process, leaving opportunities for therapeutic intervention. There is a need to search for new data on the molecular and cellular mechanisms of damage development and compensatory processes in brain neurons in the dynamics of cerebral ischemia of varying severity. At the same time, the activation of compensatory mechanisms will reduce the severity of neurodegenerative disorders in the brain, increase the effectiveness of the treatment. An important role in the development of neurodegeneration is played by protein aggregates, which can be localized in nerve cells, in the intercellular space and cerebrospinal fluid. They are formed on the basis of damaged proteins, the violation of the structure of which can be caused by hypoxic and nitrosative stress, inflammatory processes provoked by ischemia, death of neurons. Therefore, an important role in preventing the development of secondary brain damage after ischemia can be played by cellular systems responsible for protein homeostasis, the protein synthesis apparatus, chaperones, the system of autophagy and elimination of damaged proteins ((ubiquitin, proteasome), as well as energy-intensive adaptation processes.

Introduction. The role of neuroglobin ischemia is still unclear. Some studies indicate its neuroprotective effect due to increased expression of endothelial NOS. Other evidence refutes its significance for neuronal survival under oxygen-deficient conditions, as neuroglobin deficiency appears to increase HIF-1α expression. Materials and methods. The experiments were performed on 56 male outbred white rats weighing 258±18 g. Total cerebral ischemia was simulated by decapitation of animals, whereas the subtotal one was simulated by simultaneous ligation of both carotid arteries. Stepwise subtotal cerebral ischemia was performed by ligating both carotid arteries with an interval of 7 days (subgroup 1), 3 days (subgroup 2), or 1 day (subgroup 3). Results. The study found significant differences in neuroglobin content across three subgroups. In subgroup 1, there was a notable increase in neuroglobin content compared to the control group, with a 13% increase in the parietal cortex (p<0.05) and a 14% increase in the hippocampus (p<0.05). However, subgroup 2 showed a decrease in neuroglobin content, with a 13% decrease in the parietal cortex (p<0.05) and a 7% decrease in the hippocampus (p<0.05). The most significant decrease in neuroglobin content was observed in subgroup 3, with a 31% decrease (p<0.05) in the parietal cortex and a 33% decrease (p<0.05) in the hippocampus. In subgroup 3, the parietal cortex showed a 40% decrease in neuroglobin content compared to subgroup 1 (p<0.05) and a 21% decrease compared to subgroup 2 (p<0.05). Similarly, the hippocampus exhibited a 42.6% decrease in neuroglobin content compared to subgroup 1 (p<0.05) and a 28% decrease compared to subgroup 2 (p<0.05). Conclusion. Thus, the most pronounced disorders of the prooxidant-oxidant balance decreased neuroglobin were observed during a 1-day total cerebral ischemia. Keywords: neuroglobin, ischemia, pyramidal neurons, hippocampus, parietal cortex

Amino acids and their derivatives are involved in synaptic transmission as neurotransmitters and neuromodulators. However, some amino acids are involved in the formation of neuromediators. Therefore, the study of amino acid pool in subtotal cerebral ischemia (SCI) is of great importance. The aim of the study is to evaluate the changes in amino acid pool and the role of amino acids in oxidative processes in rats with SCI. Materials and Methods. The experiments were carried out on 16 male outbred white rats (260±20 g) according to Directive 2010/63/EU on the protection of animals used for scientific purposes, September 22, 2010. Results. When modeling 1-hour partial cerebral ischemia (PCI) by unilateral ligation of the common carotid artery (CCA), no pronounced morphological changes at the microscopic and ultrastructural levels were observed. Also, there were no pronounced changes in the respiratory parameters of the mitochondrial fraction (only a slight decrease in ATP-synthase was noticed). It reflects the safety of the enzymatic complexes of the electron transport chain in the ischemic model, and changes in prooxidant-antioxidant balance of brain homogenates. There was a decrease in sulfur-containing amino acids: methionine by 12 % (p<0.05) and cysteate by 28 % (p<0.05) in the parietal lobe of rats with SCI when compared with the control. Apparently, it was the result of the activation of oxidative stress. In turn, a decrease in cysteate prevents taurine synthesis. However, taurine level did not decrease, possibly due to its long half-life in the brain. Conclusion. In rats with SСI, with 1-hour ischemia, there was a tendency to glycine increase in both studied lobes, whereas excitatory amino acids tended to decrease.

The aim of the study was to investigate morphofunctional disorders of neurons in the cerebral cortex and changes in the prooxidant-antioxidant state in rats after subtotal cerebral ischemia. Material and methods. The experiments were performed on 20 white outbred male rats. Surgical interventions were carried out under intravenous thiopental anesthesia (40–50 mg/kg). Subtotal cerebral ischemia was simulated by both common carotid arteries ligation. Animals were decapitated after 60 minutes of ischemia. Morphological and functional changes in the neurons of the parietal cortex and hippocampal CA1 field, and intensity of free radical oxidative processes (content of thiobarbituric acid reactive substances and thiol-disulfide system components) in brain homogenates were studied. Results and discussion. Brain ischemia has been followed by oxidative stress in brain tissue. The cellular metabolism has been disturbed under the oxidative stress that leads to a water-electrolyte imbalance, manifested by deformation of neuron bodies, wrinkling, and swelling. The changes in parietal cortex are to a greater extent expressed, as the neurons are more sensitive to oxygen deficiency.

The purpose of the work is to analyze changes in the morphological characteristics of neurons of phylogenetical different parts of the cerebral cortex (parietal cortex and hippocampus) of rats at different periods in the dynamics of stepwise subtotal experimental cerebral ischemia. Methods . The experiments were performed on 42 males of outbred white rats. Step subtotal cerebral ischemia was performed as follows: first, one common carotid artery was ligated, simulating partial ischemia. Then, with an interval of 1 day (subgroup 1), 3 days (subgroup 2) or 7 days (subgroup 3), the second common carotid artery was ligated. Results. A microscopic study of the size, shape, degree of chromatophilia of the cytoplasm and the content of ribonucleoproteins in pyramidal neurons of phylogenetically different parts of the cerebral cortex have shown the dependence of the severity of brain damage on the interval between the cessation of blood flow in both carotid artery. Adaptation was better with a 7-day interval between dressings, while the ligation with an interval of 1 day, the degree of morphological changes was maximum indicating a lack of resources for the implementation of adaptation mechanisms.

Objective:to study the nature of changes in the content of stable metabolites of nitric oxide (NOx) - nitrites and nitrates - in the blood of patients after coronary artery bypass graft (CABG) under the conditions of artificial circulation.Material and methods.Depending on the level of [Hb] in the blood plasma, the patients with CABG surgery were divided into three groups: 1 - without IOH (Hb ≤ 0.1 g/l), n = 43, 2 - with low IOH (l IOH, Hb > 0.1 g/l and < 0.5 g/l, n = 42), 3 - with high IOH (hIOH, Hb ≥ 0.5 g/l, n = 38). The level of NOx was determined in the blood plasma of the patients.Results.At the end of CABG, compared with the baseline, the patients revealed a decrease of NOx in the blood plasma and its increase - within 5-7 days after the surgery, to the utmost in the group with high IOH.Conclusion.The change of NOx in the blood plasma depended on the severity of intraoperative hemolysis, which indicates the influence of the hemolysis products on the formation and utilization of nitric oxide.

Objective: to study the nature of changes in the content of stable metabolites of nitric oxide (NOx) - nitrites and nitrates - in the blood of patients after coronary artery bypass graft (CABG) under the conditions of artificial circulation. Material and methods. Depending on the level of [Hb] in the blood plasma, the patients with CABG surgery were divided into three groups: 1 - without IOH (Hb ≤ 0.1 g/l), n = 43, 2 - with low IOH (l IOH, Hb > 0.1 g/l and < 0.5 g/l, n = 42), 3 - with high IOH (hIOH, Hb ≥ 0.5 g/l, n = 38). The level of NOx was determined in the blood plasma of the patients. Results. At the end of CABG, compared with the baseline, the patients revealed a decrease of NOx in the blood plasma and its increase - within 5-7 days after the surgery, to the utmost in the group with high IOH. Conclusion. The change of NOx in the blood plasma depended on the severity of intraoperative hemolysis, which indicates the influence of the hemolysis products on the formation and utilization of nitric oxide.

Studies of the pathology of the brain in experimental ischemia necessitate adequate methods of assessing the neurological deficit that occurs in laboratory animals, including sensory and behavioral disorders. The purpose of the research was a comparative study of motor and behavioral disorders in rats with partial and incomplete experimental cerebral ischemia. To avoid high mortality of animals with subtotal cerebral ischemia, the author's model of a stepwise (with a break of 7 days) dressing of common carotid arteries was used for simultaneous bandaging of common carotid arteries.The study of the state of sensomotor and motor functions was carried out in the "open field" test, "muscle strength" test, "swimming test". It was found that rats after experimental cerebral ischemia had less muscle strength, were less resistant to hypoxia, and showed less motor and emotional activity. In animals with incomplete cerebral ischemia, more pronounced sensomotor and behavioral disorders were observed as compared to rats with the modeled partial cerebral ischemia and, especially, as compared to control animals.