Syndrome of hyperosmolar hypohydration in the experiment: features of morphological disorders in brain tissues of rats with homeostasis disorders of different degrees of severity

Abstract

Annotation. In neurosurgical patients, damage to the hypothalamic-pituitary region in 30% of cases can be complicated by the development of central diabetes insipidus, manifested by gross disturbances of the water-salt balance: the development of hypertonic hypohydration, which leads to functional and structural damage to organs and tissues. The purpose of the study was to simulate in an experiment the syndrome of hyperosmolar hypohydration, to investigate the peculiarities of morphological changes in brain tissues of animals depending on the level of osmolarity of blood plasma. To simulate hyperosmolar hypohydration, laboratory rats were injected intraperitoneally with furosemide solution (5.0 mg per kg-1), and under anesthesia intravenously – 2.0 ml of hyperosmolar sodium chloride solution of various concentrations (from 1.8% to 9%). The degree of hypohydration of the body, degree of hyperosmolarity, duration of coma, and lethality were studied. Pieces of the brain tissue were taken for histological examination, and their processing was carried out according to generally accepted methods. Histological slides were studied using a SEO SСAN light microscope. In hyperosmolar coma, under the conditions of administration of 7.2% sodium chloride solution to rats, blood-filled vessels with moderate perivascular edema were found in the brain tissues. Heterogeneous changes were characteristic of neurocytes, among them there were normochromic, isolated hypochromic and a significant number of hyperchromic neurocytes, and pericellular edema was detected. In brain tissues in hyperosmolar coma caused by the administration of 8.1% sodium chloride solution, an increase in amount of blood in vessels with pronounced erythrostasis was found, and small isolated hemorrhages were identified. Perivascular edema was significant in most of the vessels. Karyopyknosis and hyperchromatosis were characteristic of neurocytes, significant pericellular edema was also detected. In the tissues of the brain, in hyperosmolar coma, caused by the introduction of 9.0% sodium chloride solution, an increased amount of blood-filled vessels with pronounced erythrostasis was observed. Vessels walls were with pevascular edema, plasmarrhagia was also marked. In most fields of vision, hyper- and sharply hyperchromic neurocytes were identified, which were characterized by compaction, pyknosis, and pericellular edema. In brain tissue in hyperosmolar coma caused by intravenous administration of 7.2%, 8.1% and 9.0% solutions of sodium chloride, the appearance and progression of the following histological changes were established: blood-filled vessels, erythrostasis, small diapedesis hemorrhages, significant pevascular edema due to plasmarrhagia. Heterogeneous changes in neurocytes, with the appearance and predominance of hyper- and sharply hyperchromic cells, and significant pericellular swellings were established.