The definition of neutrophil extracellular traps and the concentration of short-chain fatty acids in salmonella-induced inflammation of the intestine against the background of vancomycin and Bacteroides fragilis

Abstract The aim is to study the features of the formation of neutrophil extracellular traps in the blood and gut-associated lymphoid tissue with salmonella-induced inflammation against the background of the administration of vancomycin and B. fragilis, and to determine the concentration of short-chain fatty acids in the luminal microflora of rats by means of chromatography-mass spectrometry. Methods. Studies were carried out on quantitative counting of Sytox+-neutrophiles and NETs in scrapings of the mucous membrane of the ileum of the intestine and in blood by the method of immunofluorescence microscopy, and also by determination of the concentration of SCFA in the luminal microflora of rats by chromatography-mass spectrometry. Results. The introduction of vancomycin contributed to an increase in the number of Sytox+-cells in scrapings of the intestinal mucosa and in the blood by 55 % and 2.5 times (group II). With the combined administration of vancomycin and S.enteritidis (III group), S. typhimurium (IV group), the mean Sytox+-cell counts in mucosal scrapings increased by 30 % and 2.4 times, and in the blood by 30 % (group IV ), there was also a decrease in the number of NETs by 40 % (group IV). The introduction of B. fragilis against the background of pretreatment with vancomycin and infection with salmonella showed a decrease of Sytox+-cells in the scrapings of the intestinal mucosa by 43 % and 53 %, and in the blood by 46 % and 58 % (V and VI groups), and the number of NETs in scrapings from the intestinal mucosa and in the blood significantly increased by 43 % and 40 % (V group), and by 2.3 and 2.0 times (group VI). When infecting the rats with S. typhimurium against the background of pretreatment with vancomycin and the introduction of B. fragilis, the concentration of acetate in the samples increased by 2 times; propionate – 6 times and butyrate – 3 times. Conclusions. The introduction of B. fragilis in the infection of S. enteritidis and S. typhimurium against the background of vancomycin pretreatment leads to decrease in the number of Sytox+-cells in scrapings from the intestinal mucosa and in the blood, but induces the generation of NETs, and also causes an increase in the concentration of SCFA in the luminal microflora of rats, which helps to reduce salmonella-induced inflammation and restore the integrity of the intestinal epithelium.