Technique for creating a permanent cecal fistula in the rat

A method was developed to surgically implant a silicone/stainless steel fistula-cannula in the cecum of freely moving rats. The specially designed fistula-cannula allows sampling of cecal contents at any time without disturbing the physiologic functions of the intestinal tract, as evaluated by observation of general well-being and postmortem macroscopic inspection. The fistula-cannula was implanted in 12 male rats under general anesthesia. The animals remained in good health during the postoperative period lasting up to 9 weeks. They gained weight normally compared with a control group (n = 8) that had not undergone surgery. Samples of 0.2 to 1.0 g of contents could be collected with a microspatula, without the need to anesthetize the animal. The model provides a useful system for sampling cecal contents without the need to sacrifice the animal. Because it allows cross-over studies to be carried out, this approach may result in significantly reducing the number of animals required for digestive studies.