Целью исследования явилось изучение особенностей нейродистрофических изменений нейронов и глии моторной коры головного мозга у крыс с разным уровнем когнитивных функций при двусторонней перевязке общих сонных артерий. Материал и методы. Исследование выполнено на 136 крысах Wistar. По результатам тестирования в водном лабиринте Морриса все животные были разделены на две подгруппы: с высоким и низким уровнем способностей к пространственному обстановочному обучению. Животных экспериментальной группы выводили из эксперимента на 1-, 6-,14-,21-, 35-, 60-и 90-е сутки после двусторонней перевязки обеих сонных артерий. Гистологические срезы моторной коры головного мозга окрашивали по Нисслю и гематоксилином-эозином. Результаты. Через 1, 6 и 8 суток после ишемии количество нейронов с необратимыми изменениями и погибших клеток достигало максимума за все время наблюдения. На 8-е сутки исследования около сосудов появлялись компактные группы глиальных клеток. Отмечалась гетерохрония: у животных с высоким уровнем когнитивных способностей рост числа нейронов с необратимыми изменениями следовал за пиком гибели клеток, а у животных низким уровнем, наоборот, максимальное количество погибших клеток приходилось на 6-е сутки, а нейронов с необратимыми изменениями-на 1-е. На 14-, 21-и 28-е сутки отмечалась постепенная стабилизация показателей, характеризующих повреждение коры больших полушарий. Средние значения площади перикарионов и ядер нейронов возрастали, ядерноцитоплазматическое отношение снижалось, отмечалось внутриклеточное набухание. Спустя 35 суток появлялись участки коры, обедненные телами нейронов и глии, возрастало количество нейронов с необратимыми изменениями, в большей степени у животных с высоким уровнем когнитивных способностей. Тенденции, характерные для первого месяца исследования: снижение ядерно-цитоплазматического отношения, нейронов без необратимых изменений, и увеличение нейроглиального индекса продолжали прогрессировать и на 60-е и 90-е сутки исследования. Апикальные дендриты пирамидальных нейронов приобретали штопорообразный ход. Компактные группы глиальных клеток исчезали. Заключение. На первой неделе церебральной гипоперфузии преобладали необратимые изменения нейронов, на второй-третей неделе происходило снижение морфологических критериев их функциональной активности. На четвертой-пятой неделе развивалась неполная адаптация в виде увеличения числа нейронов вблизи сосудов гемоциркуляторного русла и роста количества сателлитных глиоцитов, погружением их в цитоплазму нейронов. Через 2-3 месяца церебральной гипоперфузии вновь появлялись признаки острой гипоксии. Животные с высоким уровнем когнитивных способностей характеризовались большим повреждением структур нейро-глиального ансамбля.

The state of cognitive functions in cerebrovascular disorders is one of the most urgent healthcare problems. Recently obtained data convincingly indicate the participation of astrocytes in the formation of cognitive functions of the brain. We conducted a study on 88 Wistar rats. Following the results of testing the rats in a Morris water maze, all animals were divided into two subgroups: those with a high (HLA) and low (LLA) level of spatial situational learning abilities in the Morris water maze test. The animals in the experimental group (48 animals) underwent bilateral ligation of both carotid arteries. The animals were removed from the experiment on the 21st, 60th and 90th day after the operation. Glial fibrillar acidic protein (GFAP), a marker of mature astrocytes, was detected using primary polyclonal rabbit antibodies on histological sections of the precentral gyrus of the brain. Data were obtained on a more pronounced decrease in the numerical density of astrocyte bodies and the number of astrocyte main processes in HLA and LLA animals in earlier (on the 21st day) and later (on the 90th day) stages of the experiment, respectively. The growth of the area occupied by the astrocyte processes occurred earlier in HLA animals (on the 60th day after the simulation) compared to LLA animals (on the 90th day after the simulation). The conducted factor analysis confirmed the presence of two factors associated with the dynamics of the studied parameters. The conclusion is made about alternative variants of changes in the studied groups. The HLA subgroup predominantly demonstrated changes of an alterational character in earlier experimental stages, while adaptive changes were observed in the later stages of the experiment. Conversely, in the LLA subgroup, alterations and adaptations occurred in later and earlier experimental stages, respectively.

The aim of the study was to detect the features of neurodystrophic changes in neurons and glia of the motor cortex of the brain in rats with different levels of cognitive functions and stress resistance with bilateral ligation of the common carotid arteries combined with short-term physical activity.Material and methods. The study included 136 Wistar rats. All animals were divided into two subgroups depending on the results of testing in the Morris water maze: with a high and a low level of abilities for spatial environment learning. Animals of the experimental group were exposed to daily free swimming for 15 minutes, starting on the 7th and ending on the 35th days of the study. The rats were withdrawn from the experiment in 8, 14, 21, 35, 60, and 90 days after bilateral ligation of both carotid arteries. Histological sections of the precentral gyrus of the brain were stained according to Nissl and hematoxylin-eosin.Results. On the 8th day of the experiment (1 day of short-term physical activity), the hemomicrocirculatory bed of the cerebral cortex was characterized by a decrease in venous hyperemia, and a decrease of tissue edema signs around the hemocapillaries, a characteristic feature of isolated cerebral hypoperfusion. Neurons with signs of hyperfunction and rod-shaped inclusions in the nuclei (Roncoronni bodies) were detected on the 14th, 21st, 28th days. Hemocapillaries formed compact groups of cells. Further, neurodystrophic changes were less pronounced in comparison with isolated cerebral hypoperfusion, this was accompanied by a decrease in venous hyperemia, preservation of perivasal cell groups up to the 60th day of the experiment. Roncoroni bodies disappeared on the 90th day of observation.Conclusion. The effect of short-term physical activity on the development of cerebral hypoperfusion resulted in an increase in the number of neurons without irreversible changes, a decrease in neurodegenerative changes, and also reduced the severity of gliosis. The adaptive effect of short-term physical activity was more pronounced in animals with a high level of cognitive abilities, which was accompanied by a more significant decrease in the number of dead cells of the cerebral cortex. Day 28 was a critical point when gliosis and neuronal death were combined with the appearance of Roncoronni bodies and perikarion hypertrophy of some pyramidal neurons, as well as the concentration of gliocytes around hemocapillaries. The latter appears to be a sort of adaptation, since it is accompanied by a decrease in mortality in animals with a high level of cognitive abilities.

Correlation between individual typological features like sex-related characteristics and low initial level of stress resistance and unfavorable prognosis of ischemic brain damage is shown. At the same time, the astrocytes’ participation in neuroplasticity in this disease represents the purpose of the study. The goal was to study the cerebral cortex astrocytes’ morphometric characteristics during the cerebral hypoxia in rats of different sexes with different stress tolerance levels. We performed the study with 72 Wistar rats. According to the Open Field test results all the animals were divided into two subgroups: with high and low level of stress tolerance. Both carotid arteries of the experimental group animals (48 animals) were bandaged. Animals were removed from the experiment at 21, 60 and 90 days after surgery. Glial fibrillary acidic protein (GFAP), a marker of mature astrocytes, was detected on histological sections of the central brain gyrus using primary polyclonal rabbit antibodies. Progressive decrease of the astrocytes’ numerical density and the number of first order processes were obtained during the study. It was less pronounced in animals with high stress tolerance and females. Increase of the processes’ distribution area was reliably detected. Area decreased after 90th day of the experiment. It is concluded that the astrocytes’ alteration develops earlier in animals with high stress tolerance and males, later in females (60 days) and animals with low stress tolerance (90 days).

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