Mouse model of orthotopic small bowel transplantation

To investigate the surgical procedures of orthotopic small bowel transplantation (SBT) model in mice to study the function and rejection of SBT.

We established a mouse SBT allograft model as follows: the donor portal vein was anastomosed end by side with the recipient inferior vena cava; the donor superior mesenteric artery with aorta patch was anastomosed end by side with recipient abdominal aorta. After an appropriate length of the recipient's small bowel was removed, the donor's small bowel and the recipient's small bowel were end-to-end anastomosed discontinuously. The mice were fasted for 4 d after the operation, free access to water and subcutaneously injection of 2 mL of 5% glucose saline twice daily. Operation success was regarded as survival for more than 5 d. There is no antibiotic and immunosuppressor.

A total of 30 transplantations were done, the 5 d survival rate was 60% (18/30), and 12 died within 5 d. Among the dead recipients, 5 died of arterial anastomotic stenosis and anastomotic thrombosis, 2 of hemorrhagic shock caused by anastomotic bleeding, and the other 5 of intra-abdominal infection caused by postoperative intestinal fistula. The donors' operative time was (40 ± 4.5) min, warm ischemia time was about 0.5 min, donor preparation time was about 3 min, and cold preservation time was (30 ± 7.5) min. The recipients' operative time was (95 ± 8.0) min, among which, the abdominal aorta and inferior vena cava clamping time was (38 ± 3.5) min, the venous anastomotic time was (10 ± 2.0) min and the arterial anastomotic time was (15 ± 3.0) min. The mean intra-operative blood loss of the surviving recipient mice was about 0.2 mL.

High quality vascular anastomosis, and rehydration of donors and recipients are crucial factors for improving the success rate of SBT.