Cecal intubation model in the rat that facilitates selective in vivo studyof colonic epithelial biology - Preliminary report

PURPOSE: A free-living animal model with ready and repetitive access to sel ected regions of the large bowel and with minimally altered bowel anatomy a nd 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 rat s (240-260 g) had laparotomy and intubation of the distal colon and the cec um via a cecotomy with the use of two small tubes with restraints and trans mural anchors. The tubes were tunneled and anchored to the back for infusio n of fluid directly into the colon. Tube positions were studied when the an imals were killed. Animals were fed on either a 10 percent fiber diet or a fiber-free diel. Stathmokinetic assessment of the distal colon was performe d after one week of infusion with phosphate-buffered saline and sodium n-bu tyrate. RESULTS: The technique produced an easy access without affecting th e weight gain of the animals after recovery. Tube positions were accurate a fter three weeks at the time the animals were killed. Infusions of phosphat e-buffered saline and n-butyrate were well tolerated. n-Butyrate infusions twice daily for a week reversed the atrophy in the colonic mucosa induced b y dietary fiber deprivation. CONCLUSION: An in vivo large-bowel intubation model permitting selective delivery of luminal factors provides an effectiv e option for the study of colonic mucosal biology.