Effect of Chronic Predatory Stress on the Structural Organization and Hydration of the Small Intestine of Laboratory Rats

Abstract

Introduction. The effect of chronic stress on the digestive tract is an urgent issue of physiology and pathology. The aim is to study the features of histostructure, morphometric characteristics and the level of total water in the wall of the small intestine in a Wistar rat when modeling chronic predatory stress. Materials and methods. The study was conducted on 60 male Wistar rats weighing 220–370 g, divided into control and experimental groups of 30 rats each. In animals of the experimental group, chronic predatory stress was simulated by exposure to the smell of urine of predator (cat) for 10 days according to the method of V. E. Zeilikman et al. (2021). To determine the total water level, fragments of the small intestine were weighed on electronic scales before and after drying in a thermostat to a constant weight (dry residue) at a temperature of +55 °C. Histological preparations were prepared according to the standard procedure. Sections with thickness of 8 and 12 μm were stained with hematoxylin and eosin, and morphometric examination of intestinal villi and crypts was performed. Digital data were processed by methods of variational statistics. Results. When exposed to chronic stress, the rats of the experimental group showed an increase in the thickness of intestinal villi by 1.286± 0.026 times and the transverse size of the crypts by 1.128±0.268 times, which was associated with venous fullness and lymphostasis, which were accompanied by edema and swelling of the mucous membrane of the small intestine with deformation of the crypts. An increase in the total water level in the small intestine confirmed the detected changes. Conclusion. Under conditions of chronic predatory stress, stress-induced changes with morphometric and histostructural transformations develop in the small intestine of rats, which are characteristic of exudative enteropathy.