Structural changes in rat thymus in experimental hyperthermia

It is established by us, that the impact of the experimental hyperthermia (EH) on the Vistar rat organism leads to formation of accidental involution of thymus of a temporary, reversible nature. Temporary involution of this organ corresponded to «catabolic» phase of the posthyperthermal period (5 hours, 3 days after EH) which was manifested by a decrease in relative weight of the organ, reduction of the relative area of brain substance and density of lymphocytes in all zones, especially in the inner cortical substance. At a tissue level an aggravation of destructive processes, signs of perivascular hypostasis, migration of cellular elements in lymphatic spaces and capillaries were marked. By the end of the «anabolic» phase (14 days after EH) of the posthyperthermal period a virtually complete restoration of thymus was observed.