General Morphological Characteristics of the Results of Experimental Modeling of Aseptic Peritonitis.

BACKGROUND: Aseptic peritonitis is a reaction of the local immune system aimed at rejection of a foreign body, which, having antigenic properties, does not (unlike a pathogen) counteract the immune system. The suture materials, namely catgut thread, used in intracavitary surgical operations possess xenogenic properties and can be used for antigenic stimulation of the immune system of the peritoneal cavity. Consequently, we decided to use a catgut suture for antigenic stimulation of the immune system of the peritoneal cavity and to study the morphological features of the results of experimental modeling of aseptic peritonitis in albino rats. METHOD: The study involved 15 Wistar albino male rats, weighing 286,13 ± 6,26 g. To study the dynamics of destructive changes made by the catgut implant in the peritoneal cavity of the experimental animals, the animals were assigned into three groups in accordance with the time interval of their euthanasia at 3, 7, and 14 days of the experiment. RESULTS: After modeling an aseptic peritonitis, the investigation the abdominal cavity showed that in four out of five animals of the first group, that is, on day 3 of the experiment, the catgut implant had adhered to the greater omentum. The search for the fifth implant led to an unexpected discovery: we found it conjoined with the second derivative of the visceral peritoneum, similar in structure to the greater omentum, but related to the testes. On day 7, the implant embedded into the peritoneal cavity of the animals, had adhered to the serous formations of the testes in all five cases (100%, three of them - to the left epididymal omentum, and another two - to the right one). On day 14 (n = 5) it was found that in three cases it had adhered to the serous formations of the testes (60%, one of them to the left epididymal omentum, another two - to the right one) and in two cases it had adhered to the greater omentum (40%). CONCLUSION: During the experiment on implantation of a xenogenic substrate in the form of flat bundles made from the catgut thread into the peritoneal cavity of sexually mature male rats, it was found for the first time that their acceptors were not only the greater omentum, but also two derivatives of the peritoneum, homeomorphic to it and associated with the epididymides, which we reasonably called epididymal omenta and described in details.

Microscopic structure of albino rats' small intestine.

OBJECTIVE: Introduction: The small intestine of albino rats is a transitive canal between the stomach and the cecum that is closely located from each other, reaches a length of one meter, which in comparison ratio to body weight significantly exceeds the corresponding segment in humans. The aim: The paper is aimed at thorough histological study of the wall and structure of albino rats' small intestine mucosa. PATIENTS AND METHODS: Materials and methods:30 mature albino male rats were involved into the study. The specimens of albino rats' small intestine, fixed in 10% neutral buffered formalin solution, have been studied. The study was carried out using conventional histological methods for obtaining serial paraffin sections stained with hematoxylin-eosin. Epoxy plastination of individual tissue samples of the small intestine was performed. Subsequently, polished thin sections were made, stained with 1% methylene blue and 1% borax solution. The obtained specimens were studied on the "Konus" light microscope equipped with Sigeta DCM-900 9.0MP digital microphoto attachment with the Biorex 3 software adapted for studies of such type. RESULTS: Results and conclusions: For the first time in the practice of histological study of the epithelial covering of the mucous membrane of the small intestine, attention is drawn to the specific pattern of its organization on the intestinal villi. It has been found that epithelial covering consists of alternating cluster epithelial aggregations separated by fissured depressions. Since no mentioning about them has been found in the publication, these cluster aggregations of enterocytes can be called epithelial buds of the intestinal villi. Consequently, it can be concluded that with the exception of some specific morphological features, the small intestine of albino rats is homologous to human one by its histological structure, which means that it can be used as a model for various experimental studies.

Features of angioarchitecture of the albino rats stomach and small intestine.

OBJECTIVE: Introduction: The stomach and small intestine are important organs of the digestive system and, to date, they are the subject of research by morphologists, endocrinologists, immunologists, gastroenterologists, and other researchers. The aim: The paper is aimed at the study and systematization of the features of angioarchitecture of the albino rats stomach and small intestine. PATIENTS AND METHODS: Materials and methods: The study based on the injection of the blood vasculature of abdominal organs of 20 albino male rats with 5% gelatin solution, colored with filtered black ink, was performed. The specimens were subject to photographing from different aspect angles in their original state, and then, after dehydration in alcohols with the transition to pure acetone, they were embedded in the epoxy. Photographing of the obtained specimens was made by a digital camera, as well as a binocular magnifier MBS-9, equipped with a digital photoattachment Sigeta DCM-900 9.0MP. RESULTS: Results and conclusions: The results of injecting of blood vasculature of albino rats' gastrointestinal tract with ink mass clearly demonstrate the specific difference in the intraorganic angioarchitecture of its different regions, which depends entirely on their functional purpose in the digestive process. In the stomach, the highest concentration of blood microvessels is in its glandular part, which is explained by the increased nutrient needs of the secretory process of the gastric glands, while the mucous membrane of its fundus (pre-stomach) contains a scattered network of exchange microvessels that only promote the process of regeneration of the stratified squamous (partially keratinized) covering epithelium. In the small intestine, the typical principle of the organization of the microvasculature of its mucous membrane is somewhat modified in the duodenum, which is associated with the presence of mucous (Brunner's) glands in it, as well as in those sites (starting from the duodenum) where the group lymph nodes (Peyer's patches) are localized.

Comparative histological structure of the gastrointestinal mucosa in human and white rat: a bibliographic analysis.

OBJECTIVE: Introduction: According to numerous domestic and foreign researchers, morphofunctional structure of the digestive system of humans and rats have much in common, therefore, rats are used as the laboratory animals during the experiments. The aim of the paper was the comparative study of the histological structure of the gastrointestinal mucosa in human and white rat through the bibliographic analysis of the publications. PATIENTS AND METHODS: Materials and methods: The material for the investigation was current publications on the study of the histological structure of the intestine mucosa in human and white rat by analyzing, synthesizing and generalizing the resulting data. RESULTS: Review and discussion: Histologically, the gastrointestinal mucosa in white rat is similar to the human one. The gastrointestinal mucosa in white rats (with the exception of the generic difference in the structure of the stomach and the caecum), in its histological structure, is quite similar to the human one, to be studied in the experimental simulation of the specific lesions of the digestive system.

General comparative anatomy of human and white rat digestive systems: a bibliographic analysis.

OBJECTIVE: Introduction: The gastrointestinal tract of humans has much in common with most species of laboratory animals, particularly at the level of microscopic study. White rats are widely used in the experiments to determine the influence of the environmental factors on the human. The aim: Study the general comparative anatomy of the digestive system of the human and the white rat through the bibliographic analysis of the publications. PATIENTS AND METHODS: Materials and methods: Current scientific publications on the study of the human and the white rat gastrointestinal tract morphology were used as the material for the research by analyzing, synthesizing and generalizing the information obtained. RESULTS: Review and conclusions: Generally, the anatomical structure of the white rat digestive system is similar to the human one. Phylogenetically, the digestive systems of humans and rats are the homologous functional system that are much in common regarding the structure and functions of the organs, the significance of which is in the perception, mechanical and chemical (enzymatic) digestion and absorption of the nutrients into the body.