Diversion-related experimental colitis in rats

PURPOSE: Diversion-related colitis is an inflammatory process that affects the colon and/or rectum distal to a colostomy. Its mechanisms are unknown, and many hypotheses have been considered. The aim of the present study was to create an experimental model of diversion-related colitis in rats, so in the future it will be possible to test different hypotheses. METHODS: Three groups of ten male Wistar rats were used for the study. Two groups underwent a colostomy and were kept alive for 6 or 17 weeks. One group of rats was killed at the onset of the experiment. Specimens were taken in bypassed segments in the rats who had had a colostomy and in the sigmoid colon for the control group. Histologic analysis using standard coloration, histochemical techniques, and bacterial preparation was used to find histologic or changes of colonic histology or flora. RESULTS: Exclusion was associated with vascular congestion, a decrease in length of glandular crypts (P < 0.01), and an erosion of surface epithelium; inflammation of the mucosa was absent in all control animals and present in all test animals. In contrast, the number of goblet cells was not changed by the procedure. There was also a significant change in distribution and intensity of sulfomucins and sialomucins and quantitative and qualitative changes of the colonic flora. CONCLUSION: This experimental model of diversion colitis is characterized by histologic and bacteriologic modifications comparable with those reported in humans but with different histochemical changes.