Bacterial translocation from defunctionalized rat small bowel

Bacterial translocation from the intestine may cause severe infectious complications in a number of clinical situations, including the short bowel syndrome and after small bowel transplantation. The aim of the present study was to develop a simplified model for the study of bacterial translocation from a defunctionalized intestine. An ileal segment from untreated or cyclosporine-treated rats was exteriorized as a Thiry-Vella loop. After 1, 3. or 7 days, bacterial translocation and distribution of immunocompetent cells were assessed. The data obtained were compared with data from animals subjected to intestinal transplantation. Translocation to the mesenteric lymph nodes was detected in 60% of the Thiry-Vella loop animals on day 1. in 100% on day 3, and in 83% on day 7: concomitantly, the number of macrophages and T-cells in the mesenteric lymph nodes increased from day I until day 7. The degree of bacterial translocation on days 3 and 7 in animals with a Thiry-Vella loop was comparable with that observed 7 days after intestinal transplantation. Furthermore, treatment with cyclosporine A enhanced the number of translocating bacteria. In the model presented here bacterial translocation occurs from the small bowel to the mesenteric lymph nodes. The model offers possibilities to study the mechanisms and immunological phenomena associated with microbial translocation.