An important role in the implementation of the adaptive reactions of the organism to the action of stress factors, as well as in protecting the body from adverse environmental factors is played by the epiphysis, which is a neuroendocrine organ. Therefore, stress reactions are accompanied by reactive changes in the morphology of the epiphysis, which is actively involved in the process of adaptation, changing the functional activity. Of particular interest are changes in the morphometric parameters of the pineal cells, since they are a marker of the functional state of the pinealocytes, and, accordingly, of the epiphysis. The purpose of our study was to determine the morphometric changes of pinealocytes in rats under chronic stress conditions. The study was conducted on 16 sexually mature males of the Wistar line rats. Animals were under standard vivarium conditions under natural changes of light and dark part of the day and were divided into 2 groups: intact and experimental. Simulation of chronic stress was carried out through hyperdynamia. The rats were placed in a reservoir with water of 10 liters for 10 minutes for forced swimming. One-time training was carried out for 10 days. According to the results of our morphometric studies of pineal cells of experimental animals, a significant reduction in the area of the cytoplasm and the nucleus of active light pinealocytes compared with the control group of animals, which is definitely the result of a decrease in their functional activity due to the influence of stress factors and indicates a decrease in the processes of intracellular synthesis. It was found that in light active pinealocytes, the average area of the cytoplasm decreases by 14.21% (p <0.001), the average nucleus area decreases by 23.59% (p <0.001), the average nucleus area is 13.58%. It was found that the average area of the cytoplasm and nuclei of low-activity dark cells decreases by 13.50% and 24.78% respectively. The nucleus in the dark pinealocytes does not appear, which can be explained by excessive filling of the karyoplasma with a basophilic substance that “disguises” the nucleolus of the cell. Reducing the area of the nucleolus indicates a decrease in the synthesis of rRNA required for the synthesis of protein. The phenomena of nucleus picnosis with the predominance of heterochromatin densification processes is the main reason for the reduction of the area of nuclei in the experimental animals. Also, a reduction in the area of the nucleus can be associated with the transition of a functionally active eucharoma to a functionally inactive heterochromatin having a small transcriptional capacity. Euchromatin is a less compact and condensed form of chromatin, in which more genes are capable of transcription in a specialized cell. It is possible to assume a decrease in the level of transcription and protein synthesis in conditions of chronic stress, due to the energy deficit of the pineal cell. At the same time, an increase in the nuclear-cytoplasmic ratio indicates a decrease in the cell area, which is consistent with the decrease in protein synthesis. Thus, the results of the morphometric study of pineal cells indicate a decrease in the functional activity of the epiphysis, indicating a decrease in the morphometric indices of both light and dark pineal cells.
pineal gland, rats, pineal cells, stress
«Bulletin of problems biology and medicine» Issue 4 Part 2 (147), 2018 year, 298-300 pages, index UDK 591.481.3
