Cervical small bowel transplantation in the rat: a useful tool

Orthotopic intestinal transplantation in the rat is highly successful, but circumstances may require an extraabdominal graft location. We describe a microsurgical technique for cervical intestinal transplantation in the rat, which has been used to investigate the immune status of hosts already bearing an intraabdominal bowel transplant. A 10 cm segment of donor jejunum is harvested on a pedicle of superior mesenteric artery and superior mesenteric vein. In the recipient, the carotid artery (CA) and external jugular vein (EJV) are isolated. The venous anastomosis is performed end to end to the medial EJV branch, and the arterial anastomosis is completed end to side to the CA. Both anastomoses are performed with interrupted 10-0 nylon. The bowel is placed in a subcutaneous pocket in the neck, with both ends exteriorized. The procedure was performed in 11 donor-recipient pairs planned to elicit rejection, graft-vs.-host disease (GVHD) or graft acceptance. No technical complications were encountered. All rats survived long term, and their grafts were monitored histologically. The expected immune responses were observed, but rejection and GVHD were not fatal to the host with this model. We conclude that this technique is feasible and reliable to monitor the progress of isolated intestinal transplants. The location in the neck does not disrupt normal intestinal function of the recipient and may have multiple applications in the study of intestinal transplant immunology and physiology.