Microbiome of the pre-epithelial biofilm of the colon of albino rats with experimental thyrotoxicosis

Abstract

Background. The microbiome of the pre-epithelial biofilm of the large intestine in direct contact with the body also interacts with the immune and other systems that emphasizes the urgency of its study in various diseases. The purpose of the study was to determine the taxonomic composition, population level, analytical microecological indicators and the degree of microecological disorders of the pre-epithelial biofilm of the large intestine in albino rats with thyrotoxicosis. Materials and methods. Experiments were carried out on 25 mature male albino rats weighing 220–240 g, of which 15 animals were included to the control group (intact animals), and 10 rats — to the main group. The experimental thyrotoxicosis was simulated by intragastric administration of L-thyroxine for 14 days. Under sterile conditions, a laparotomy was performed, a segment (up to 3 cm) of the large intestine with its contents was taken. The washed portion of the intestine was homogenized with a sterile 0.9% NaCl solution. A series of ten-fold dilutions with 10–2 to 10–7 concentrations of the initial mixture were prepared. From each tube, 0.01 ml were seeded on solid optimal nutrient media with subsequent isolation and identification of microbes according to morphological, tinctorial, cultural and biochemical properties. Results. In some animals, bifidobacteria and lactobacilli, as well as bacteroides and escherichia, are eliminated. A significant deficiency of not only bifidobacteria by 48.50 % and lactobacillus by 94.59 %, but also of bacteroides by 44.85 % was established. Determination of the quantitative dominance of each taxon showed that the dominant role of bifidobacteria in the microbiocenosis is reduced by 82.76 %, lactobacillus — by 2.20 times, and the role of bacteroides in the microbiocenosis of the epithelial biofilm of the large intestine of albino rats with the experimental thyrotoxicosis — by 43.04 %, E.coli — by 7.18 %, but the role of opportunistic enterobacteria and staphylococci, which contaminated and colonized the mucosa of the large intestine, increased substantially. Conclusions. Experimental thyrotoxicosis is accompanied by a partial elimination from the biotope of the pre-epithelial biofilm of the large intestine of bifidobacteria and lactobacilli, as well as bacteroides. There comes elimination from the colic mucous membrane in all experimental animals of peptostreptococcus, clostridia and enterococci, as well as colonization of the biotope with opportunistic enterobacteria (proteus, klebsiella) and staphylococci.

Keywords

• thyrotoxicosis
• microflora
• large intestine
• pre-epiepithelial biofilm