肠易激综合征患者肠道菌群特征及其与肠黏膜肥大细胞活化的关系

Characteristics of intestinal flora in patients with irritable bowel syndrome and its relationship with the activation of mast cells in the intestinal mucosa

目的探讨肠易激综合征(IBS)患者肠黏膜菌群特征及其与肠黏膜肥大细胞(MC)活化的关系。方法收集IBS患者25例(IBS组)和健康受试者13例(对照组)的结肠黏膜标本,其中IBS腹泻型15例(IBS-D组)、IBS不定型10例(IBS-U组)。采用高通量测序平台检测肠道黏膜菌群及丰度,Alpha多样性分析评价肠道菌群物种多样性,甲苯胺蓝染色法观察肠黏膜MC数量及活化情况(MC脱颗粒),分析IBS患者肠道黏膜菌群与肠黏膜MC活化的关系。结果各组肠黏膜菌群在门水平占比前三位均为变形菌、厚壁菌、拟杆菌,肠黏膜菌群多样性指数差异无统计学意义。IBS-D、IBS-U组在属水平中毗邻贫养菌丰度低于对照组、泰氏菌丰度高于对照组(P均<0.05),IBS-D组中互营烃降解菌、卟啉单胞菌、大理石雕菌、心杆菌丰度高于IBS-U组、对照组(P均<0.05)。各组MC计数差异无统计学意义;IBS-D组与IBS-U组MC脱颗粒率均高于对照组(P均<0.05),IBS-D组与IBS-U组比较差异无统计学意义。IBS组肠黏膜MC脱颗粒率与毗邻贫养菌的丰度无明显相关性(r=0.113,P>0.05),与泰氏菌的丰度呈正相关(r=0.723,P<0.01)。结论IBS患者肠道黏膜菌群以变形菌、厚壁菌、拟杆菌为主,菌群多样性无明显变化,部分菌群丰度发生改变,且不同亚型肠黏膜菌群丰度变化不同;IBS患者肠黏膜MC脱颗粒率明显升高,且与泰氏菌丰度存在一定相关性。

Objective To investigate the characteristics of intestinal flora in patients with irritable bowel syndrome(IBS)and its relationship with the activation of mast cells(MC)in the intestinal mucosa.Methods The colon mucosa samples of 25 patients with IBS(IBS group)and 13 healthy subjects(control group)were collected,including 15 cases of diarrhea-predominant IBS(IBS-D group)and 10 cases of unsub typed IBS(IBS-U group).The intestinal flora and its abundance were detected by high-throughput sequencing platform,the species diversity of intestinal flora was evaluated by Alpha diversity analysis,the number and the activation of MC in intestinal mucosa(MC degranulation)were observed by toluene blue staining,and the relationship between intestinal flora and the activation of MC in IBS patients was analyzed.Results At phylum level,among the intestinal mucosa flora in each group,the top three strains were Proteobacteria,Firmicutes,and Bacteroidtes;there was no significant difference in diversity index of intestinal flora.At genus level,the abundance of Granulicatella in IBS-D and IBS-U groups was lower than that of the control group,while the abundance of Tissierella in the IBS-D and IBS-U groups was higher than that of the control group(all P<0.05),the abundance of syntrophaceae,Porphyromonas,Marmoricola,Cardiobacterium in the IBS-D group was higher than that of the IBS-U group and the control group(all P<0.05);there was no significant difference in MC count among different groups;the degranulation rates of MC in the IBS-D group and IBS-U group were higher than that of control group(all P<0.05),but there was no significant difference between IBS-D group and IBS-U group.In the IBS group,the MC degranulation rate of intestinal mucosa was not significantly correlated with the abundance of Granulicatella(r=0.113,P>0.05),but was positively correlated with the abundance of Tissierella(r=0.723,P<0.01).Conclusions The intestinal flora of IBS patients mainly consist of Proteobacteria,Firmicutes,and Bacteroidtes,and there is no significant change in the diversity of intestinal flora.The abundance of some microbiota changes in patients with IBS,and the abundance of intestinal flora in different subtypes of IBS patients is different.The degranulation rate of intestinal mucosa mast cells in patients with IBS increases,and there is a certain correlation between the degranulation rate and the abundance of Tissierella.