CHARACTERISTICS OF SMALL INTESTINE STRUCTURAL COMPONENTS IN INTACT AND CONTROL RATS

Chronic enteritis is manifested by the number of changes in the mucous membranes over three divisions of the small intestine. Morphologically this is presented by tissues atrophy and sclerosis, by changes in its architecture, and enterocyte adhesions. This results in the functional disorders including the lipid metabolism impairment, the suppression of the exocrinocyte functioning, and some others, but the size of exocrine glands along the length of the small intestine is still unchanged. The small intestine is an actively functioning organ. Its villi and folds expand the area of the mucous membrane in almost 500 times; while the area of the small intestine active surface, which can come into direct contact with various affecting factors, is 200-300 m2. Therefore, the small intestine is still requiring more detailed study. However, the reports on comparing data on the morphological features of the small intestinal wall in white rats of the Wistar line, which are the most commonly used in experiments, are far from being as multitudinous in the medical and experimental literature as it was expected. This study was aimed at identifying and comparing the peculiarities in the structure and morphofunctional parameters of small intestine in rats. The study of the morphofunctional status of structural components in the small intestine (duodenum, hollow, iliac) wall was performed on 60 sexually mature Wistar male rats weighing 140-190 g, which were kept under standard conditions of the vivarium, Ukrainian Medical Stomatological Academy. All the manipulations with animals were carried out in accordance with the “Rules for the Use of Laboratory Animals” (2006, Annex 4) and the mandates of the Declaration of Helsinki and the Guide for the Care and Use of Laboratory Animals. The animals were divided into 4 groups: Group I included intact rats (n=15); Group (control) II included rats, which had their outer thigh incised (n=15); Group (control) III included animals treated intraperitoneally with 1 ml of saline solution (n=15); Group (control) IV included animals, which were given injections of 1 ml of saline solution intraperitoneally and had their outer thigh incised (n=15). The studying the structure of the small intestine wall in rats has demonstrated this of control animals does not differ from that in the group I intact rats. A deeper analysis has been performed by using morphometric methods to find out statistically significant differences between the parameters studied. The statistical analysis has shown that the morphometric parameters (overall wall thickness, mucosal layer thickness, submucous layer thickness, muscular layer thickness, and serous layer sickness) of the small intestine (duodenum, jejunum,ilium) in the rats of control groups (II, III, IV respectively) during all study periods demonstrate no statistically significant difference. The difference reliability was insignificant at p> 0.05. Comparison of these indices with those in the intact group has pointed out that the difference reliability was also insignificant (p> 0.05). This fact will enable to carry out further comparing the studied morphometric parameters using the values presented by the intact rats only, without using data obtained in the control group of the rats.