THE STATE OF MICROBIOTS AND MORPHOLOGICAL CHANGES OF THE SMALL INTESTINE IN EXPERIMENTAL ACUTE GENERALIZED PERITONITIS ON THE BACKGROUND OF STREPTOSOTOCIN-INDUCED DIABETES MELLITUS
Authors: Verveha В. М. 
Published: July 2021

The aim of the work: to analyze the microbiota and to study the morphological structure of the small intestine in the dynamics of acute peritonitis on the background of streptozotocin-induced diabetes mellitus.

Materials and methods. Experimental researches were performed on 52 adult white male rats. The main group of animals was divided into three subgroups, on which bacteriological examination of parietal intestinal biotope and morphological examination of the small intestine on the first, third and seventh days of acute peritonitis on the background of concomitant diabetes were carried out. Diabetes mellitus was simulated by a single intraperitoneal injection of streptozotocin (60 mg / kg). On day 14 of diabetes mellitus, rats were injected with 0.5 ml of 10 % filtered fecal suspension into the abdominal cavity and acute generalized peritonitis was initiated. The control group consisted of rats (n=8), which were injected subcutaneously with saline 0.9 % NaCl.

Results and discussion. Bacteriological examination of the parietal intestinal biotope and morphological examination of the small intestine were performed. In the first subgroup of animals with acute peritonitis on the background of streptozotocin-induced diabetes mellitus, the dominant microbiota isolated from the parietal intestinal habitat was represented by Escherichia coli (70 %), Candida spp. (20 %) and Staphylococcus spp. (20 %). A monoculture of microorganisms was identified in 40 % of animals. In the second subgroup, the number of microbial associations increased to 78 %. Three-component associations predominated in the third subgroup, dominated by Escherichia coli (57 %) and Enterobacter aerogenes (43 %). In the control group of animals Bifidibacterium spp., Lactobacillus spp., Escherichia coli, Staphylococcus spp were found. The progression of the inflammatory process on the background of hyperglycemia was accompanied by the increase in the number of Enterobacter aerogenes, Bacteroides spp, Candida spp. and by the decrease in the number of Escherichia coli. The results of morphological examination of the mucous membrane of the small intestine of rats at different stages of development of this combined pathology indicate the development of an active inflammatory reaction, which is the basis for the deterioration of absorption function and enteral insufficiency syndrome. Alterative changes manifested by uneven vacuolation of villi epithelial cells, areas of epithelial desquamation, as well as severe infiltration of the mucous membrane by neutrophilic granulocytes, monocytes and lymphocytes increased throughout the experiment and were most characteristic of animals of the third subgroup, mortality in which reached 38 %.

Conclusions. The results of bacteriological examination of the parietal intestinal biotope of animals with acute peritonitis on the background of streptozotocin-induced diabetes mellitus indicate the dominance of Escherichia coli (65 %), Enterobacter aerogenes (23 %), Candida spp. (23 %), Bacteroides spp (19 %) among the representatives of the microbiota of the small intestine.

The development of the inflammatory process of the peritoneum on the background of hyperglycemia is accompanied by a decrease in the height and thickness of the villi, crypt depth, dystrophic changes of mucosal cells, which indicates the decrease in the barrier function of the small intestine and is the cause of bacterial translocation, which is enhanced by qualitative and quantitative changes in microbes (predominance of associations of pathogens of aerobic gram-negative microorganisms and fungi of the genus Candida).