[ULTRA STRUCTURAL CHARACTERISTIC OF THYROID GLAND IN RATS EXPOSED TO EXOGENOUS CHRONIC HYPERTHERMIA OF MEDIUM DEGREE]

The unfavorable effect of high temperature accompanies people in both - natural hot climatic conditions and in condition of work. Overheating causes long structural and functional changes in the body, which contribute to the development of destructive processes. In this regard, we have investigated the ultra structural characteristic of the thyroid gland under the influence of prolonged overheating. The study was carried out on 60 Wistar's rats with an average weight of 180-230 g (10-12 weeks). Exogenous hyperthermia was created with the help of a thermal chamber. The I group consists of control rats, which were also kept in a thermal chamber for 5 hours at a temperature of 21° C, II group - animals exposed to chronic hyperthermia of moderate severity (42.0-43.1°C). Hyperthermia was simulated between 8 am and 1 pm (5 hours a day) during 60 days. After sessions of sixty-day hypertemia on days 1, 7, 15 the rehabilitation of animals was removed from the experiment by decapitation under ether anesthesia. Thus, investigating ultra structural changes, specifically: a large number of "openwork" thyrocytes, dark nuclei, a reduced number of microvilli on the apical membrane, a lack of folding of the basal membrane, dilated cavities of the granular endoplasmic reticulum, deformed organelles, presence of interstitial vesicles with erythrocytes and interfollicular spaces endotheliocytes, it can be concluded that the function of thyrocytes has changed in the direction of decrease.