title: [Changes in the structure of the lymphoid organs of rats during prolonged hypokinesia].
abstract: The thymus and the spleen in the male rats sacrificed on the 30th, 60th, 90th, 120th and 165th days of hypokinesia, as well as 2 and 3 months after its termination have been studied by means of certain histological methods. The organs in question are subjected to involution that depends on development of a stress reaction. The most acute changes develop during the first month of hypokinesia, that coincides with the alarm stage of the stress-reaction. Subsequently, the rats gradually adapt to the new conditions of their existence, that corresponds to the resistance stage of the general adaptation syndrome. Stabilization of the mass and structure of the spleen, as well as a deceleration rate of the thymus involution are specific for the resistance stage. A reduced mass of the thymus under hypokinesia depends on a decreasing amount of the lymphoid tissue, and a reduced mass of the spleen depends on disappearing the elements of the erythropoietic raw and on a decreasing number of lymphocytes. No normalization of the structure and function in the lymphoid organs is observed at the resistance stage of the hypokinesia stress. After hypokinesia is stopped, the cellular composition and mass of the spleen normalize and the erythropoietic function of the spleen is the first to of the spleen normalize and the erythropoietic function of the spleen is the first to restore. The mass and structure of the thymus do not normalize during the readaptation period after hypokinesia. This can produce premature immunological aging of the organism.
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D004920:Erythropoiesis; D006965:Hyperplasia; D008297:Male; D009929:Organ Size; D010950:Plasma Cells; D051381:Rats; D011919:Rats, Inbred Strains; D012149:Restraint, Physical; D013154:Spleen / Q000473:pathology*; D013312:Stress, Physiological / Q000473:pathology*; D013950:Thymus Gland / Q000473:pathology*
vernacular_title: Izmeneniia struktury limfoidnykh organov krys pri dlitel'noĭ gipokinezii.