Test of long‐term uterine survival after allogeneic transplantation in rabbits

Aim To see if: (i) a large vessel aortocaval vascular patch technique may bring about long-term graft survival after allogeneic uterine transplantation (UTn) in a rabbit model; and (ii) fertility can be achieved following natural mating post-allogeneic UTn. Methods Allogeneic uterine cross transplantations were performed in New Zealand white rabbits using an aortocaval macrovascular patch harvested as part of the uterine allograft. Five rabbit recipients received a uterine graft from five unrelated donor rabbits. All female rabbits were unrelated and were of proven fertility with at least one previous litter each. Tacrolimus was administrated for immunosuppression post-transplant. Natural mating was attempted if long-term survival had been achieved. The main outcome measures were: (i) long-term recipient survival; (ii) long-term adequate uterine perfusion; and (iii) successful pregnancy post-UTn. Results All five recipient animals survived the surgery with satisfactory immediate postoperative recovery. Recipients 1, 2 and 4 died within the first 4 postoperative days. Both long-term survivors failed to conceive following introduction of a proven male breeder despite evidence of mating. Necropsy at 9 and 11 months showed a lack of patency of uterine cornua at the point of anastomosis, albeit a small uterus in recipient 3 and a reddish brown amorphous material at the site of the transplanted uterus in recipient 5. Conclusion We have demonstrated the feasibility of uterine allotransplantation using a macrovascular patch technique, but could not demonstrate conception because of blocked cornua. To address this, we propose using embryo transfer techniques in order to achieve conception.