Comparison of 2 Heterotopic Heart Transplant Techniques in Rats: Cervical and Abdominal Heart

Objectives: Heterotopic heart transplant in rats has been accepted as the most-commonly used animal model to investigate the mechanisms of transplant immunology. Many ingenious approaches to this model have been reported. We sought to improve this model and compare survival rates and histologic features of acute rejection in cervical and abdominal heart transplants. Materials and Methods: Rats were divided into cervical and abdominal groups. Microsurgical techniques were introduced for vascular anastomoses. In the abdominal heart transplant group, the donor's thoracic aorta was anastomosed end-to-side to the recipient's infrarenal abdominal aorta, and the donor's pulmonary artery was anastomosed to the recipient's inferior vena cava. In the cervical heart transplant group, the donor's thoracic aorta was anastomosed to the recipient's common carotid artery, and the donor's pulmonary artery was anastomosed to the recipient's external jugular vein. Survival time of the 2 models was followed and pathology was examined. Histologic features of allogeneic rejection also were compared in the cervical and abdominal heart transplant groups. Results: The mean time to recover the donor's hearts was 7.4 +/- 2.2 minutes in the cervical group and 7.2 +/- 1.8 minutes in the abdominal group. In the cervical and abdominal heart transplant models, the mean recipient's operative time was 23.2 +/- 2.6 minutes and 21.6 +/- 2.8 minutes. Graft survival was 98% and 100% in the cervical and abdominal heart transplant groups. There was no significant difference in graft survival between the 2 methods. Heart allografts rejected at 5.7 and 6.2 days in the cervical and abdominal transplant groups. There was no difference in the histologic features of acute allogenic rejection in cervical and abdominal heart transplant. Conclusions: Both cervical and abdominal heart transplants can achieve a high rate of success. The histologic features of acute allogeneic rejection in the models are comparable.