The Experimental Study In The Change Of Intestinal Barrier Of The Rat Pouchitis

Objective:To produce the rat model of ileal pouchitis, and research the change of intestinal barrier of the rat with ileal pouchitis,and explore the mechanism of change. Methods:The rat models of ileal pouch were produced by using the microsurgical technique, and the rat models were randomly divided into group IPAA(operated with the build of ileal pouch and drinking normal water postoperatively) and group DSS(operated with the build of ileal pouch and drinking 5%DSS for 4 days from the postoperative 30 th day), while the sham(operated with abdominal cavity Open-Close and drinking normal water postoperatively) was set as control. During the experiment, the body weight, hematochezia and fecal score were recorded. All of the rats were sacrificed in the postoperative 35 th day. The terminal ileum from the sham, the ileal pouch and proximal ileum from group IPAA and group DSS were obtained for HE staining and histological assessment. Immunohistochemistry was performed for the assessment of MPO and occludin. The concentration of D-lactic acid in the blood was determined with colorimetric method. The transcription level of IL-1β, IL-6, TNF-α and IL-10 m RNA in the tissue were assessed by real-time fluorescent quantitative PCR.Results:All of rats’ postoperative weight gradually increased after a short-term weight loss. The rats of group DSS experienced continuous weight loss again from the postoperative 30 th day to 35 th day, while the sham and group IPAA continued to gain weight. All of rats from group DSS experienced hematochezia(6/6), while none of rats from the sham(0/6) or group IPAA(0/6) experienced hematochezia. The fecal score of group DSS was lower than that of the sham(P<0.01) and group IPAA(P<0.01), and the fecal score of group IPAA was lower than that of the sham(P<0.01). The histological score of pouch was higher than that of the terminal ileum and the proximal ileum(P<0.01). The histological score of pouch from group DSS was higher than that of group IPAA(P<0.01), while there was no statistical difference in the ileal score of 3 groups(P>0.05). The MPO level, the concentration of D-lactic acid and the m RNA transcription level of IL-1β, IL- 6 and TNF-α of group DSS and IPAA were higher than that of the sham(P<0.01), and that of group DSS was higher than that of group IPAA(P<0.01). The occludin level and the m RNA transcription level of IL-10 of group DSS and IPAA were lower than that of the sham(P<0.01), and that of group DSS was lower than that of group IPAA(P<0.01).Conclusion 1. Successfully producing the rat model of ileal pouch and inducing the rat model of pouchitis with DSS.2. The structure and function of intestinal barrier in the rat model of pouchitis was damaged, and the extent of damage was positively associated with the degree of inflammation.3. The relative increase of pro-inflammatory factors and the relative decrease of anti-inflammatory factors promote the damage of intestinal barrier.4. The treatment aiming to pro-inflammatory factors and anti-inflammatory factors may be effective for the recovery of intestinal barrier structure and function.