FEATURES OF GERONTOLOGICAL REORGANIZATIONS OF TISSUE STRUCTURE AND CELLULAR COMPOSITION OF THE THYMUS IN THE RIVER OTTAR IN THE TERRITORY OF THE BELARUSIAN SECTOR OF THE CHERNOBYL NUCLEAR POWER PLANT EXCLUSION ZONE

Involutional changes, developing during ontogenesis and under the influence of radiation in various thymus cells heterochronically, are of a general nature, both for parenchyma cells and for the microenvironment. Together with fibrous connective tissue, adipose tissue is introduced into the lobules, a large number of fibroblastic cells are noted in the medulla. Numerous lobules with parenchyma completely replaced by fibrous connective and adipose tissue are also observed. Along with this, only in individual lobules were isolated Hassall's corpuscles found, in which the distribution of S-100+ dendritic cells decreases by 10.23 times to 1.50±0.05%. The distribution of S-100+ dendritic cells depending on topography and the change in their morphofunctional characteristics in general, is directly dependent on the age and exposure of the river otter to incorporated radioactive substances.