PECULIARITIES OF MORPHOLOGICAL CHANGES IN BRAIN STRUCTURES OF RATS UNDER CONDITIONS OF MODEL TRAUMATIC BRAIN INJURY

Experimental animal models of traumatic brain injury (TBI) were created to study themorpho-functional features of the disease and to fill the therapeutic window betweenpreclinical trials and the introduction of drugs into the clinical medical practice.The aim of the work – to study the morphological changes in the brain structures ofrats under conditions of model TBI.Material and methods. The experiments were performed on white male rats weighing160-190 g. The experimental model of TBI in rats under conditions of propofolanesthesia (60 mg/kg) was caused by the action of a stream of carbon dioxide underpressure, which was created using a gas cylinder air gun. For histological examination,the brain was fixed with 10% neutral formalin, dehydrated in alcohols in increasingconcentrations, and immersed in paraffin. Sections were stained with hematoxylinand eosin, toluidine blue. The microscopy of histological specimens was performedusing a light microscope OLIMPUS BX 41 using magnifications of 40, 100, 200 and400 times. The morphological research studied the structural changes of neurons inthe sensorimotor zone of the cerebral cortex, the hippocampal structures of the CA1zone and the condition of blood vessels in two groups of animals: Group II - rats withsimulated trauma.Results. In animals with model TBI, there was a predominance of the number ofdegenerating pyramidal neurons over those preserved in the sensorimotor zone ofthe cortex of the large hemispheres and in the CA1 zone of the hippocampus. In thesensorimotor zone of the cortex of the large hemispheres, the death of neurons wasmanifested by morphological signs of karyopyknosis, karyorexis and cytopicnosiswith the phenomena of cytolysis. Only single preserved neurons were visualized in thepyramidal layer; most cells are represented by pyknotic cells; 3) in the hippocampusof animals with TBI, the cytolytic type of nerve cell death was mainly observed. Themorphological signs of cytolysis indicate deep damage to all neurocyte structures.Conclusions. The morphological basis of the remodeling of brain structures in traumaticbrain injury is: reduction in the number of normochromic neurons in experimentalanimals, formation of a significant number of hypochromic neurons, formation ofhyperchromic neurons with pronounced signs of tigrolysis, hemodynamic disorderswith pericellular and perivascular edema.