MORPHOLOGICAL FEATURES OF HIPPOCAMPUS PYRAMIDAL NEURONS STRUCTURE IN DIFFERENT AGE PERIODS OF LIFE

Manifestation of age-related cognitive impairment is memory decline, the mechanism of which is associated with the activity of the brain as a whole, but the structures of the hippocampus are of particular importance for the process of memorizing current events. Cognitive impairment can be a result of both physiological involutional changes and a sign of neurodegenerative processes. The aim of the study was to evaluate the structural features of the pyramidal neurons of the hippocampus in individuals of different age groups. Using histological, immunohistochemical and morphometric methods, we examined autopsy material (100 samples) obtained from individuals of both sexes of 4 age categories: 22-35 years (n=16), 36-55(60) years (n=30), 56(60)-74 years (n=26) and 75-90 years (n=28). The results of the study showed the presence of dystrophic changes in the hippocampal neurons in individuals of different age categories with a significant predominance of such cells in individuals of the older (elderly and senile) age groups, as evidenced by statistically significantly (p < 0.05) smaller average sizes of neuron bodies in all fields of the hippocampus, compared with similar ones in the group of individuals of the first mature age (p<0.05), as well as in the CA1 and CA3 fields compared with individuals of the second mature age. In mature age, changes in the structure of neurons were mainly reactive in nature. Expressed structural changes of an irreversible nature were observed mainly in the older (elderly and senile) age group. Thus, the conducted study revealed the presence of signs of dystrophic changes in the pyramidal neurons of the hippocampus in individuals of older age groups. With age, the maximum cross-sectional area of ​​all cerebral ventricles increases, the relative volume of vascular plexuses decreases, the relative volume of connective tissue grows, it most likely replaces the cells of the vascular plexuses. The accumulation of Tau protein in the cytoplasm of cells in the CA1 and CA3 fields of the hippocampus in individuals of this age category indirectly indicates the presence of a structural basis for a certain degree of cognitive deficit and a high risk of neurodegenerative pathology.

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