SOME PATTERNS OF CHANGES IN THE LYMPHOCIRCULATORY SYSTEM OF THE INTESTINE AFTER GASTRIC RESECTION

Аннотация

The present study investigates morphological and histochemical changes in the lymphocirculatory system of the small intestine following various types of gastric resection in dogs. A total of 122 dogs were examined, including 104 that underwent gastric resection using different methods (Billroth I, Kupriyanov-Zakharov, Hofmeister-Finsterer, and Polna-Reichel) and 18 in the control group. Structural transformations of lymphatic capillaries and vessels were analyzed over different postoperative periods ranging from 3 days to 1 year. Significant alterations were observed in the mucosal lymphatic network, including capillary dilation, new anastomoses, and wall protrusions. Pathohistological examinations revealed edema, infiltration by lymphocytes and plasma cells, deformation of villi and crypts, and epithelial atrophy. These changes were most prominent in the early postoperative period, with partial recovery and adaptation over time. The findings highlight compensatory remodeling of intestinal lymphatic vessels aimed at restoring microcirculation and lymphatic drainage under conditions of venous stasisand interstitial edema caused bysurgical trauma. Keywords: gastric resection, small intestine, lymphatic system, morphology, histochemistry, villi, anastomosis. Despite the significant number of studies devoted to the investigation of the lymphatic system of the gastrointestinal tract under various pathological conditions, certain questions remain unresolved. This is especially true regarding changes in the lymphatic network of the small intestine after different types of gastrectomy procedures [2,3,5]. Gastrectomy, regardless of the method used, is accompanied not only by the removal of a significant portion of the organ but also by damage to nerves and blood vessels. This undoubtedly affects the morphological condition of the lymphatic network, not only of the stomach itself but also of other abdominal organs. Therefore, the issues related to lymphatic system pathology associated with damage to thedigestivetract—particularly due togastrectomy—remain highly relevant [1,4]. Objective of the Study: To investigate the morphological and functional changes in the intestinalwall and itslymphatic network after various types of gastrectomy. Materials and Methods: The study was conducted on 122 mongrel dogs. Of these, 104 animals underwent gastrectomy using the following techniques: Billroth I, Kupriyanov-Zakharov, Hofmeister–Finsterer, andPolya–Reichel. The remaining 18animals served as the control group. To study the structural changes in the lymphatic vessels of the small intestine, animals were euthanized at 3,7, 15days; 1,1.5,2,3, and 6months; and1year after gastrectomy. At theend of each experimental period, animals were euthanized via overdose of narcotic agents (hexenal or https://ijmri.de/index.php/jmsi volume 4,issue3,2025 402 thiopental sodium). Intra-organ lymphatic vessels were examined using an isolated segment of the small intestine, 12–15 cm in length, taken 35–40 cm from the duodenojejunal flexure. These vessels were filled with Gerota’s mass via interstitial injection. Then, clarified specimens were prepared and studied underan MBS-2 binocular microscope. In the examination of 492 specimens obtained from 82 dogs, attention was paid to the external structure, orientation of the lymphatic vessels and their loops, the presence of anastomoses, and the density of the vascular pattern. The diameters of lymphatic loops, capillaries, and vessels, as well as the protrusions and lateral bulges on their walls, were measured — a total of 37,520 measurementswere performed. To study the pathohistological and histochemical structures of the small intestine walls, samples were taken from 2 dogs in each group at 3, 7, 15, and 30 days after gastrectomy (a total of 32 animals). Histological and histochemical examinations of the intestinal wall were conducted. For microscopic examination, tissuesamples were takenfrom the initial section ofthe small intestine. The samples were fixed in a 10% solution of neutral formalin, passed through a series of alcohols, and embedded in paraffin. The resulting 6–8 μm thick sections were stained with hematoxylin-eosin and by Van Gieson's method, and PAS (Periodic Acid–Schiff) reaction was applied. Quantitative indicators were statistically analyzed using the “ES-1020” computer system. Significancewas accepted at levels ofP <0.05,P <0.01,and P< 0.001. Research results and discussion:It was found that, at various intervals after gastrectomy, the restructuring of the lymphatic network is characterized by an increase in the density of the network across all layers of the intestinal wall. The most significant changes occurred in the lymphatic network of the mucous membrane. These capillaries were dilated and convoluted. In some areas, they were swollen and formed anastomoses at different levels. The loops varied in shape, with the following average dimensions: length — 61.0 ± 3.0 μm (P < 0.001)