Rejection patterns in allogeneic uterus transplantation in the mouse.

BACKGROUND Transplantation of the uterus in the mouse has been developed as a model system for research towards human uterine transplantation. Previous studies in a mouse model have demonstrated that a syngeneic uterus transplant can give rise to normal offspring. The aim of this study was to characterize the time course of rejection in a fully allogeneic mouse uterus transplantation model. METHODS Uteri of BALB/c mice were transplanted to a heterotopic position in C57BL/6 recipients, whose native uteri were left in situ. The blood flow of the uteri, their gross appearance and general histology and the density of T-lymphocytes were examined on postoperative days 2-28. RESULTS Macroscopic signs of rejection were apparent from day 5. At the light microscopy level, minimal inflammatory changes were seen from day 5 and massive inflammation was seen from day 10 to day 15. At day 28, necrosis and fibrosis were seen. The density of T-lymphocytes (CD3(+)) was increased in the grafted uterus from day 2 in the myometrium and from day 5 in the endometrium. Blood flow in the grafted uteri was reduced from day 15. CONCLUSION A murine model to study rejection of allogeneic uterus transplants was characterized. Signs of rejection were seen from day 2 to day 5 and severe rejection was seen from day 10 to day 15. The data will be useful in future studies on immunosuppressants in this model.