炎症性肠病（IBD）是慢性迁延的难治性疾病，病理机制复杂。IBD被称为屏障性疾病，且无菌鼠不能诱导出IBD，这均与肠道菌群相关。即当肠道菌群失调时，使黏膜屏障受损，增加条件致病菌及其成分入侵黏膜的机率，其代表成分胞壁酰二肽（MDP）在肠腔大量存在，与肠上皮细胞等胞内的模式识别受体NOD2结合后，引起肠黏膜免疫系统过度活化，诱发或加重IBD，因此NOD2被认为是IBD发病的易感基因。黄芩汤在治疗IBD同时可改善肠道菌群，故本研究以IBD小鼠模型及肠上皮细胞HT-29等炎症细胞模型为基础，采用LC-MS、16SrDNA测序、FCM、IF、FISH、RT-PCR和Western Blot等技术，通过分析肠道菌群、黏膜屏障以及MDP-NOD2通路蛋白等，证明黄芩汤治疗IBD的机制与肠道菌群、黏膜屏障和MDP-NOD2通路密切相关，也为中药复方治疗难治性疾病的研究提供可借鉴的思路。

Inflammatory bowel disease (IBD) is a chronic refractory disease because of its complex pathogenesis. It is also known as a barrier disease, and the germ-free mice can’t be induced IBD, both are associated with intestinal flora. That is, the intestinal dysbacteriosis induces the damage of mucosal barrier, which increases the invasion of opportunistic pathogens and their compositions into the mucosa. Muramyl dipeptide (MDP) is a typical invader of them, which is present in the intestinal lumen massively, through combining with the pattern recognition receptor NOD2 in the intestinal epithelial cells and macrophages, it can cause over activation of intestinal mucosal immune system, then induce or aggravate IBD, so the NOD2 is also considered as susceptibility genes in the pathogenesis of IBD. Huangqin decoction can restore the microbial homeostasis during the treatment of IBD, but the specific target is unclear yet. So we choose IBD mice as the disease model in our program, the HT-29 cells and RAW264.7 cells will be used, and we will adopt some advanced techniques as LC-MS, 16SrDNA sequence, FCM, IF (confocal), FISH, RT-PCR and Western Blot to complete the intestinal flora diversity analysis, and the mucosal biology and histological barrier detection, and the MDP-NOD2 pathway protein analysis, which is in order to prove that the mechanism of Huangqin Decoction and its active ingredients performing on the IBD is closely related to the intestinal flora, mucosal barrier and MDP-NOD2 pathway, it also provides a reference for the study of Chinese herbal compounds in the treatment of refractory and complex diseases.