Nowadays, the effect of external factors on the human body is constantly increasing, which leads to the emergence of certain problems of adaptive-compensatory and destructive processes in tissues and organs in conditions of water and salt metabolism disorder. Pathological states of the organism as a result of dehydration disrupt the structural and functional state of the human body, which further determines the course of the disease and causes significant changes in all systems and organs. The purpose of our experiment was to investigate the structure of the thyroid gland by means of the histochemical method of research in conditions of extracellular dehydration of the mild and severe degree. Material and methods. The research was conducted on 24 not purebred, sexually mature male laboratory rats. The structure and functional state of the thyroid gland of selected animals and humans are quite similar; this explains the feasibility of conducting research on rats. The off-cell dehydration of the mild and severe degree was modeled using a certain dietary and drinking regimen and the addition of distilled diuretic furosemide to the bisled water in a ratio of 1 ml of preparation per 1 liter of water. The diet consisted of boiled food accompanied by protein products, thus creating conditions for keeping animals on a desalted diet. The rats were divided into two groups: the mild degree of extracellular dehydration, which occurred on the 30th day, was modeled in the first group and the severe degree of dehydration obtained on the 90th day, was observed in the second group. During the collection of biomaterial for experimental study, the right part of the thyroid gland of the animal was extracted and separated. Wiring and manufacturing of paraffin blocks were carried out using a conventionally accepted method. The obtained preparations were stained with a Schiff reaction. Afterwards they were photographed and examined on a digital morphometric complex consisting of a binocular microscope and a digital system. Results and discussion. In conditions of extracellular dehydration of the mild degree in the thyroid gland, there occurs mosaicism in the structure of the follicular lobules. One part of the thyroid parenchyma has signs of a decrease in morphofunctional activity, as evidenced by an increase in the size of the follicles, the accumulation of bright PAS-positive colloid, flattening of thyrocytes and their desquamation. As a result of decreasing the size of the follicles and dilution of the colloid, the activity of regenerative processes in other lobes increases, thus a phenomenon of folliculogenesis is observed. The level of damage to the entire morphological system of the thyroid gland in the conditions of severe degree of extracellular dehydration characterizes the involvement of the connective tissue of the organ in the process, so its felting, swelling and separation from the follicular parenchyma are observed. Conclusions. Morphological changes in the tissue of the thyroid gland in conditions of extracellular dehydration emphasize a significant decrease in the morphofunctional activity of the organ, i.e. its hypofunction, and also show widespread phenomena of damage to tissue and cell structures of the organ. The results of the present study encourage future research on morphofunctional changes of the thyroid gland during the simulation of cellular and general dehydration by means of raster microscopy, as well as studying the chemical composition of the organ.
Keywords: thyroid gland, colloid, thyrocytosis, extracellular dehydration
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