Relationship between intestinal mucosal mast cells and intestinal flora during intestinal ischemia-reperfusion in mice / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the relationship between intestinal mucosal mast cells and intestinal flora during intestinal ischemia-reperfusion(I/R) in mice.Methods:Forty-eight healthy male C57BL/6 mice, aged 9-12 weeks, weighing 20-25 g, were divided into 4 groups ( n=12 each) using a random number table method: sham operation group (group Sham), sham operation plus mast cell membrane stabilizer cromolyn sodium (CS) group (group Sham+ CS), I/R group and I/R+ CS group.The intestinal I/R injury was induced by clamping the superior mesenteric artery for 45 min followed by 4 h of reperfusion in I/R and I/R+ CS groups.The superior mesenteric artery was only exposed but not occluded in Sham and Sham+ CS groups.CS 50 mg/kg was intraperitoneally injected once a day for two weeks before surgery in Sham+ CS and I/R+ CS groups.The equal volume of normal saline was intraperitoneally injected once a day for two weeks before surgery in Sham and I/R groups.Mice were then sacrificed and intestinal tissues were harvested for examination of the pathological changes of intestinal mucosa with a light microscope after HE staining, and the damage to intestinal tissues was assessed and scored according to Chiu.The expression of mast cell tryptase was detected using the immunohistochemical SP staining method, and the mast cells were counted.The intestinal contents were collected, the total amount of bacteria in intestinal flora was detected by 1% agarose gel electrophoresis, and the diversity (Chao1 index and Shannon index) and relative abundance of intestinal microbial bacteria were detected by 16S rDNA sequencing method. Results:Compared with Sham group, the Chiu′s score and mast cell count were significantly increased, the expression of mast cell tryptase was up-regulated, the total amount of intestinal flora bacteria was increased, Chao1 index and Shannon index were decreased, the relative abundance of Bacteroidetes, Proteobacteria, Bacteroides and Enterobacteriaceae were increased, and the relative abundance of Firmicutes, Lactobacillus and Bifidobacteria was reduced in I/R group ( P<0.05 or 0.01), and no significant change was found in the parameters mentioned above in Sham+ CS group ( P>0.05). Compared with I/R group, the Chiu′s score and mast cell count were significantly decreased, the expression of mast cell tryptase was down-regulated, the total amount of intestinal flora bacteria was decreased, Chao1 index and Shannon index were increased, the relative abundance of Bacteroidetes, Proteobacteria, Bacteroides and Enterobacteriaceae were reduced, and the relative abundance of Firmicutes, Lactobacillus and Bifidobacteria was increased in I/R+ CS group ( P<0.05 or 0.01). Conclusion:The activation of intestinal mucosal mast cell can lead to imbalance of intestinal flora, decrease the number of probiotics and increase the number of potential pathogenic bacteria, and thus be involved in the pathophysiological mechanism of intestinal I/R injury in mice.