Basic Study
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. May 7, 2015; 21(17): 5242-5249
Published online May 7, 2015. doi: 10.3748/wjg.v21.i17.5242
Novel isolated cecal pouch model for endoscopic observation in rats
Kurodo Koshino, Nobuo Kanai, Masayuki Yamato, Teruo Okano, Masakazu Yamamoto
Kurodo Koshino, Nobuo Kanai, Masakazu Yamamoto, Institute of Gastroenterology, School of Surgery, Tokyo Women’s Medical University, Shinjuku-ku, Tokyo 162-8666, Japan
Nobuo Kanai, Masayuki Yamato, Teruo Okano, Institute of Advanced Biomedical Engineering and Science, Tokyo Women’s Medical University, Shinjuku-ku, Tokyo 162-8666, Japan
Author contributions: Koshino K designed and performed the research; Kanai N contributed to the discussion and edited the manuscript; Yamato M, Okano T and Yamamoto M supervised this research.
Supported by Formation of Innovation Center for Fusion of Advanced Technologies in the Special Coordination Funds for Promoting Science and Technology “Cell Sheet Tissue Engineering Center (CSTEC)” and the Global COE program, Multidisciplinary Education and Research Center for Regenerative Medicine (MERCREM) of the Ministry of Education, Culture, Sports Science, and Technology (MEXT), Japan.
Ethics approval: The study was reviewed and approved by the Tokyo Women’s Medical University Institutional Review Board.
Institutional animal care and use committee: All procedures involving animals were reviewed and approved by the Institutional Animal Care and Use Committee of Tokyo Women’s Medical University (IACUC protocol number: 14-69).
Conflict-of-interest: We declared no conflicts of interest regarding this study.
Data sharing: No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Masayuki Yamato, PhD, Institute of Advanced Biomedical Engineering and Science, Tokyo Women’s Medical University, 8-1 Kawadacho, Shinjuku-ku, Tokyo 162-8666, Japan. yamato.masayuki@twmu.ac.jp
Telephone: +81-3-53679945 Fax: +81-3-53596046
Received: November 8, 2014
Peer-review started: November 8, 2014
First decision: December 11, 2014
Revised: December 24, 2014
Accepted: February 5, 2015
Article in press: February 5, 2015
Published online: May 7, 2015
Processing time: 185 Days and 17.4 Hours
Abstract

AIM: To create a new rat model for drug administration, cell transplantation, and endoscopic examination for the treatment of intestinal diseases.

METHODS: F344/NJc l-rnu/rnu rats (10-wk-old males, 350-400 g) were used in this study. The rats were anesthetized via 2% isoflurane inhalation. The rat’s cecum was isolated from the intestines, and a pouch was created. The remainder of the intestines was rejoined to create an anastomosis. The “side-to-side” anastomosis (SSA) technique initially involves the creation of a 2-cm longitudinal incision into each intestinal wall. To create an anastomosis along the ileal and colonic walls, both intestines were cut, and a continuous suture procedure was performed that included all layers of both intestines. The serous membrane was sutured along the edge and on the anterior wall of the anastomosis. The “end-to-end” anastomosis (EEA) technique was compared with the SSA technique. In the EEA technique, the frontal surfaces of both cut intestinal lumens were joined together by continuous sutures. Additional sutures were made at the serosa. After the anastomotic intestine was successfully constructed, the two intestinal lumens that were cut at the isolated cecum were managed. In addition, one luminal side of the pouch remained open to create an artificial anus on the dorsum as a passage for the residual substances in the pouch. Finally, small animal endoscopy was used to observe the inside of the pouch.

RESULTS: In this animal model, mucus and feces are excreted through the reconstructed passage. Accordingly, the cecal pouch mucosa was not obstructed or contaminated by feces, thus facilitating observations of the luminal surface of the intestine. The endoscopic observation of the cecal pouch provided clear visualization given the absence of feces. The membrane surface of the cecum was clearly observed. Two methods of creating an anastomotic intestine, the “SSA” and “EEA” techniques, were compared with regard to animal survival rate, complication rate, and operation time. The SSA technique resulted in a significantly increased survival rate and a lower incidence of complications in rat models compared with the EEA technique. The complications of stenosis and leakage resulted in death in the EEA technique. Thus, the EEA technique exhibited a lower survival rate compared with the SSA technique. However, the SSA technique required a significantly longer operation time compared with the EEA technique.

CONCLUSION: Our new rat model is potentially useful for the development of a novel treatment for intestinal diseases.

Keywords: Animal model; Anastomosis; Endoscopy; Cecal pouch; Microsurgery

Core tip: The most innovative feature of this study involved the creation of a cecal pouch that was isolated from the intestines and rejoined to create an anastomosis and an artificial anus on the rat’s dorsum that consisted of one side of a cut that remained open on the lumen of the cecal pouch. Feces were excreted via the anastomosis. Thus, the pouch mucosa was not contaminated by feces, and the luminal surface remained clean. This feature enables endoscopic observation via the artificial anus. Furthermore, drug administration or cell transplantation into the pouch can be easily and repeatedly performed through the artificial anus, and temporal changes can be observed via endoscopy.