Introduction. The incidence rate of necrotizing enterocolitis is 2.4:1000 of newborns. The number of complications reaches 51-68%, and mortality rate varies from 4 to 80%. The aim of the study was to present current data of Russian and foreign experimental studies related to necrotizing enterocolitis in children. Results. Currently, infants with low and very low body weight constitute the most proportion of patients with enterocolitis; the development of the disease in this cohort of patients has its distinctive features. In this regard, the issues of pathogenesis, the impact of risk factors and methods of prevention of the pathological process remain underinvestigated. Experimental models were used to study the features of the toll-interleukin 1 receptor domain containing adapter protein (TIRAP), the etiology of Toll-like receptor 4 expression, and the reasons for the increased levels of inflammatory mediators. The mechanism of intestinal-brain reciprocal communication was confirmed. The role of the bacterial flora and effectiveness of the antibacterial drug effect on this flora was also determined. Biomarkers of enterocolitis, such as an epidermal growth factor, interleukins, claudins 2, 3, 4, were detected using experimental modeling. Various options for disease prevention ranging from ischemic preconditioning to probiotics application and breastfeeding were analyzed, the latter ones having beneficial ability to form natural defenses in newborns. Conclusions. Thus, necrotizing enterocolitis is a severe systemic disease. Experimental modeling allows analyzing the most complex, unsolved problems and introducing novel knowledge into clinical practice.

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The purpose and objectives of the study: is to create an experimental model of a chemical burn of the esophagus with alkali to study the pathological transformation of the tissues of the upper gastrointestinal tract.Materials and methods. On the basis of the Department of Experimental Medicine with a vivarium of the Privolzhsky Research Medical University, the study of a chemical burn of the esophagus was carried out on 15 sexually mature male Wistar rats. The burn was simulated by exposure to caustic soda (NaOH) with a concentration of 20 %, 15 %, 10 % and 5 % in a volume of 1 ml. As part of the morphological study, the experimental material was fixed in 10 % formalin. After fixation, the preparations were sent to a standard histological wiring using an Excelsior ES apparatus (Thermo Scientific). Pouring into paraffin blocks using the “HistoStar” filling station (Thermo Scientific), staining with hematoxylin and eosin. For morphometric processing and creation of a video archive of the obtained material, a Leica 2500 microscope, ×4, ×10, ×20, ×40, objective, ×10 eyepiece based on the morphology department of NIITO PIMU was used.Results. Seeding with a 20 % alkali solution for animals turned out to be incompatible with life, since a day after the injection of the substance, 3 rats died, 2 were in an agonal state. Morphological examination revealed total necrosis (100 %) of the epithelial lining up to the muscle layer and partially in the muscle layer. When burned with a 15 % NaOH solution, the males were in a very serious condition, out of 5 inoculated in 2 cases, a lethal outcome was noted on the 1st day. Histological examination revealed massive necrosis (70 %) of the epithelial lining. The effect of 10 % alkali on the general condition of the animals did not show a pronounced severity of injury. Necrosis was diagnosed on 15 % of the area of the epithelial lining. A burn with 5 % sodium hydroxide solution did not provoke a severity incompatible with life. In this condition, focal necrosis was revealed, occupying about 5 % of the organ area.Conclusion. Seeds with 10 % and 5 % caustic solutions are relevant for further experimental research, since they make it possible to test different methods of diagnostics, treatment and prevention of scarring at different depths and morphological features of damage.

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