Establishment of ileal J pouch-anal anastomosis model in rats

Abstract

Objective To establish stable model of proctocolectomy and ileal J pouch-anal anastomosis (IPAA) in rats. Methods Sixty male specific pathogen free Sprague Dawley rats, weighting between 310 g and 340 g, were randomly divided into IPAA group (n=30, undergoing proctocolectomy, ileal J-pouch formation and ileal pouch-recta stump anastomosis) and control group (n=30, undergoing sham operation). Survival rates of rats at postoperative 24-h, 7-d, 30-d were observed. Operation time, and postoperative body weight, food-intake, water-intake and fecal scores were recorded as well. Transanal radiography was performed to estimate the condition of ileal pouch after 30 days of surgery. Ileal pouch specimens of IPAA group and terminal ileum specimens of control group were obtained for histological assessment. Results In IPAA group, operation time was (158.74±7.68) min. Survival rates of rats at postoperative 24-h, 7-d, 30-d were 100%, 96.67%, 90% respectively. Body weight decreased to the lowest (230.47±5.18) g at about postoperative 9-d with average amplitude of (98.43±4.06) g and recovered to preoperative body weight at about postoperative 21-d. Food-intake and water-intake increased gradually after surgery and reached normal quantities around 9 days postoperatively. Fecal score in IPAA group at postoperative 7-d was significantly higher than that in control group (1.63±0.49 vs. 0.20±0.42, P 0.05). Radiography showed filling-well ileal pouches without leakage. Histological results showed villous shortening and reduced Paneth cells in ileal pouch mucosa, and normal mucosa in terminal ileum specimens of control group. Conclusion Stable rat IPAA model is established successfully, which can more ideally simulate IPAA procedure in human beings. Key words: Rats; Ileal pouch-anal anastomosis; Models; Ulcerative colitis