Cecal intubation model in the rat that facilitates selective in vivo study of colonic epithelial biology: A preliminary report

PURPOSE: A free-living animal model with ready and repetitive access to selected regions of the large bowel and with minimally altered bowel anatomy and physiology would facilitate the in vivo study of luminal factors on the colonic mucosa in a steady-state environment This study describes a novel model of large-bowel intubation in the rat. METHOD: Four Sprague-Dawley rats (240-260 g) had laparotomy and intubation of the distal colon and the cecum via a cecotomy with the use of two small tubes with restraints and transmural anchors. The tubes were tunneled and anchored to the back for infusion of fluid directly into the colon. Tube positions were studied when the animals were killed Animals were fed on either a 10 percent fiber diet or a fiber- free diet. Stathmokinetic assessment of the distal colon was performed after one week of infusion with phosphate-buffered saline and sodium n-butyrate RESULTS. The technique produced an easy access without affecting the weight gain of the animals after recovery Tube positions were accurate after three weeks at the time the animals were killed. Infusions of phosphate-buffered saline and n-butyrate were well tolerated. n-Butyrate infusions twice daily for a week reversed the atrophy in the colonic mucosa induced by dietary fiber deprivation. CONCLUSION. An in vivo large-bowel intubation model permitting selective delivery of luminal factors provides an effective option for the study of colonic mucosal biology.