A Rat Model of Pouchitis Following Proctocolectomy and Ileal Pouch-Anal Anastomosis Using Dextran Sulfate Sodium

Summary

This protocol describes the method for establishing a rat model of pouchitis. The ileal pouch model was created by performing ileal pouch-anal anastomosis (IPAA) surgery using microsurgical techniques. After the surgery, the rat was treated with 4% dextran sulfate sodium (DSS) for 4 days.

Abstract

Ulcerative colitis (UC) is a chronic immune-mediated disease that affects the entire colon and rectum with a relapsing and remitting course, causing lifelong morbidity. When medical treatment is ineffective, especially in cases of massive gastrointestinal bleeding, perforation, toxic megacolon, or carcinogenesis, surgery becomes the last line of defense to cure UC. Total colorectal resection and ileal pouch-anal anastomosis (IPAA) offer the best chance for long-term treatment. Pouchitis is the most common and troublesome postoperative complication. In this investigation, microsurgery is employed to create an ileal pouch model in experimental rats via IPAA surgery. Subsequently, a sustained rat model of pouchitis is established by inducing inflammation of the ileal pouch with dextran sulfate sodium (DSS). The successful establishment of rat pouchitis is validated through analysis of postoperative general status, weight, food and water intake, fecal data, as well as pouch tissue pathology, immunohistochemistry, and inflammatory factor analysis. This experimental animal model of pouchitis provides a foundation for studying the pathogenesis and treatment of the condition.

Introduction

Pouchitis is a non-specific inflammation that affects the ileal pouch and is a prevalent complication following total proctocolectomy and ileal pouch-anal anastomosis (IPAA) in individuals with ulcerative colitis (UC)^1,2,3. This condition has a relatively high occurrence rate of up to 50% and can cause various clinical manifestations, including diarrhea, abdominal pain, fecal blood loss, and fever. The exact cause of pouchitis remains elusive, although some researchers believe that a shift in the pouch flora may trigger immune activation and subsequent inflammation

Protocol

All animal experiments were performed in accordance with the policies of the Tianjin Medical University General Hospital ethical committees. Male Sprague-Dawley rats aged between 9 and 12 weeks, weighing approximately 320-360 g, were used for this study. The details of the reagents and equipment used are listed in the Table of Materials.

1. Animal selection and maintenance

1. Select a healthy animal (body weight of ~220-240 g).
2. Ensure that t.......

Discussion

Ulcerative colitis (UC) is a chronic intestinal inflammation characterized by recurrent epigastric pain, diarrhea, and mucus bloody stool. It primarily affects the rectum and may involve the progressing colon to varying degrees. Surgery plays a crucial role in managing UC^17,18,19. Since Parks et al.²⁰ introduced total colectomy with an ileal pouch-anal anastomosis (IPAA) procedure in 1978 to remove altere.......

Materials

Name	Company	Catalog Number	Comments
Anhydrous ethanol	Tianjin Fengchuan Chemical Reagent Technology Co., Ltd	China	Hematoxin-eosin Staining
Dextran Sulfate Sodium	Yeasen	60316ES76	Used to induce pouch inflammation
Formaldehyde solution	Tianjin Zhiyuan Reagent Company	China	Hematoxin-eosin Staining
Gauze	Jiangxi Zhonggan Medical Equipment Company	China	Used for animal microsurgery
Hematoxylin	Beijing Zhongshan Jinqiao Company	China	Hematoxin-eosin Staining
Interferon γ  Detection reagent kit	Cloud-clone	SEA049Ra	Detecting inflammatory factors
Interleukin-10 detection kit	Cloud-clone	SEA056Ra	Detecting inflammatory factors
Interleukin-17 detection kit	Cloud-clone	SEA063Ra	Detecting inflammatory factors
Interleukin-6 detection kit	Cloud-clone	SEA079Ra	Detecting inflammatory factors
Iodophor	Tangpai Medical Equipment Co., Ltd	China	Used for animal microsurgery
Microscopic manipulation instruments	Aesculap	Germany	Used for animal microsurgery
Occludin	abcam	ab216327	Immunohistochemical testing
Sewing needle	Yangzhou Fuda Medical Equipment Co., Ltd	China	Used for animal microsurgery
tumor necrosis factor α Detection reagent kit	Cloud-clone	SEA133Ra	Detecting inflammatory factors
Two person binocular surgical microscope	OPTON	Germany	Used for animal microsurgery
Xylene	Tianjin Yingda Rare and Precious Reagent Factory	China	Hematoxin-eosin Staining