Effect of mild moxibustion on intestinal microbiota and NLRP6 inflammasome signaling in rats with post-inflammatory irritable bowel syndrome
Effect of mild moxibustion on intestinal microbiota and NLRP6 inflammasome signaling in rats with post-inflammatory irritable bowel syndrome
复制标题
DOI：
10.3748/wjg.v25.i32.4696
复制
发表时间：
2019-08-28
影响因子：
4.3
通讯作者：
Wu, Huan-Gan
中科院分区：
文献类型：
--
作者：
Bao, Chun-Hui;Wang, Chun-Ye;Wu, Huan-Gan
背景
大约三分之一的难治性肠易激综合征（IBS）病例是由胃肠道（GI）感染/炎症引起的，被称为感染后/炎症后肠易激综合征（PI - IBS）。尽管已知肠道微生物群和宿主含NOD样受体家族 pyrin结构域6（NLRP6）炎症小体信号与PI - IBS密切相关，且艾灸对PI - IBS有治疗作用，但艾灸是否调节PI - IBS中的肠道菌群和宿主NLRP6相关事件仍不清楚。
目的
研究艾灸对PI - IBS中肠道微生物群和宿主NLRP6炎症信号的调节作用。
方法
将Sprague - Dawley大鼠分为正常对照组、模型对照组、温和艾灸组和假温和艾灸组。温和艾灸组的PI - IBS大鼠在双侧天枢（ST 25）和足三里（ST36）进行艾灸，连续7天，每次10分钟。假手术组大鼠给予与温和艾灸组相同的处理，但艾条不点燃。测量腹部撤回反射（AWR）评分以评估内脏敏感性，并测量结肠组织病理学和超微结构、结肠髓过氧化物酶（MPO）活性以及血清C - 反应蛋白（CRP）水平以评估大鼠的轻度结肠炎症。通过16S rDNA PCR检测大鼠粪便中选定肠道细菌的相对丰度，并通过免疫荧光、实时定量聚合酶链反应（qRT - PCR）和蛋白质印迹法（Western blot）检测结肠中的NLRP6炎症小体信号。
结果
与假手术组相比，温和艾灸组的AWR评分显著降低，血清CRP和结肠MPO水平所反映的轻度肠道炎症受到抑制。温和艾灸显著增加了PI - IBS大鼠肠道中乳酸杆菌、双歧杆菌和普拉梭菌的相对DNA丰度，但降低了大肠杆菌的相对DNA丰度。此外，温和艾灸通过促进NLRP6以及降低含CARD的凋亡相关斑点样蛋白（ASC）和半胱天冬酶 - 1（Caspase - 1）的mRNA和蛋白质表达，诱导肠道凝集素1的mRNA和蛋白质表达，但抑制白细胞介素 - 1β、白细胞介素 - 18和抵抗样分子β的表达。各组中乳酸杆菌、双歧杆菌、普拉梭菌和大肠杆菌的相对DNA丰度与结肠中NLRP6、ASC和Caspase - 1的mRNA和蛋白质表达相关。
结论
这些发现表明，温和艾灸可通过调节肠道微生物和控制NLRP6炎症小体信号来缓解PI - IBS中的轻度胃肠道炎症并减轻内脏高敏感性。
BACKGROUNDAbout one-third of refractory irritable bowel syndrome (IBS) cases are caused by gastrointestinal (GI) infection/inflammation, known as post-infectious/post-inflammatory IBS (PI-IBS). Although it is known that intestinal microbiota and host NOD-like receptor family pyrin domain containing 6 (NLRP6) inflammsome signaling are closely related to PI-IBS and moxibustion has a therapeutic effect on PI-IBS, whether moxibustion regulates the intestinal flora and host NLRP6 events in PI-IBS remains unclear.AIMTo examine the regulatory effect of moxibustion on intestinal microbiota and host NLRP6 inflammatory signaling in PI-IBS.METHODSSprague-Dawley rats were divided into a normal control group, a model control group, a mild moxibustion group, and a sham mild moxibustion group. PI-IBS rats in the mild moxibustion group were treated with moxibusiton at bilateral Tianshu (ST 25) and Zusanli (ST36) for 7 consecutive days for 10 min each time. The sham group rats were given the same treatment as the mild moxibustion group except the moxa stick was not ignited. Abdominal withdrawal reflex (AWR) score was measured to assess the visceral sensitivity, and colon histopathology and ultrastrudure, colonic myeloperoxidase (MPO) activity, and serum C-reactive protein (CRP) level were measured to evaluate low-grade colonic inflammation in rats. The relative abundance of selected intestinal bacteria in rat feces was detected by 16S rDNA PCR and the NLRP6 inflammsome signaling in the colon was detected by immunofluorescence, qRT-PCR, and Western blot.RESULTSThe AWR score was significantly decreased and the low-grade intestinal inflammation reflected by serum CRP and colonic MPO levels was inhibited in the mild moxibustion group compared with the sham group. Mild moxibustion remarkably increased the relative DNA abundances of Lactobacillus, Bifidobacterium, and Faecalibacterium prausnitzii but decreased that of Escherichia coli in the gut of PI-IBS rats. Additionally, mild moxibustion induced mRNA and protein expression of intestine lectin 1 but inhibited the expression of IL-1 beta, IL-18, and resistance-like molecule beta by promoting the NLRP6 and reducing the mRNA and protein expression of apoptosis-associated speck-like protein containing CARD (ASC) and cysteinyl-aspartate-specific proteinase 1 (Caspase-1). The relative DNA abundances of Lactobacillus, Bifidobacteria, Faecalibacterium prausnitzii, and Escherichia coli in each group were correlated with the mRNA and protein expression of NLRP6, ASC, and Caspase-1 in the colon.CONCLUSIONThese findings indicated that mild moxibustion can relieve low-grade GI inflammation and alleviate visceral hypersensitivity in PI-IBS by regulating intestinal microbes and controlling NLRP6 inflammasome signaling.