Successful orthotopic uterine allotransplantation in a rabbit model using aorta and cava anastomoses: a short-term viability study.

Purposes: We aim to develop a rabbit model system for studies on uterus transplantation.

Methods: Six sexually mature female New Zealand white rabbits of proven fertility were used for harvesting the uterine allograft with an aortic-caval macrovascular patch (including the aorta, inferior vena cava, common and internal iliacs, and uterine arterial and venous tree). The patches were transplanted in the six recipients orthotopically using aorta and cava anastomoses. Tacrolimus (0.5 mg twice daily, p.o.) was administered postoperatively for immunosuppression.

Results: Surgical survival was 100% (n = 6), and the graft survival rate was 83.3% (n = 5). No rabbits died intraoperatively, but only one achieved short-term survival (for 8 days). Four rabbits (#1, #2, #3 and #4) died within the first 24 h as a result of veno-vena anastomosis breakdown, bradycardia, intestinal necrosis, and respiratory failure, respectively. Rabbits #5 (30 h) and #6 (8 days) died from intestinal obstruction and pneumonia, respectively. Uterine morphology was normal in rabbit #6, and rejection was not observed in the grafted uterus, which was further verified by H&E and immunohistochemistry.

Conclusions: Aorta and cava anastomoses can be used to ensure a viable transplanted uterus by reconstructing an adequate blood supply to the transplanted uterine graft in a rabbit model. We have demonstrated the feasibility of tacrolimus monotherapy in suppressing the rejection of an allotransplanted uterus in a rabbit model. However, UTx in a rabbit model seems difficult to achieve long-term survival.