A subcutaneous heterotopic limb transplantation model in the mouse for prolonged allograft survival

A heterotopic position of a limb allograft is advantageous in the fragile mouse model to reduce mortality but is prone to autotomy. The purpose of this study was to describe a new heterotopic limb transplantation model in the mouse for prolonged allograft survival. Eleven lower hindlimbs were transplanted in a heterotopic subcutaneous position in the groin of the recipient animal with the donor skin inset as a skin paddle for monitoring. Seven transplants were syngeneic (Balb/c) and four were allogeneic (C57Bl/6 donor). The overall success rate (acute survival < 7 days) was 73% (8/11) and the mortality rate was 18% (2/11). Five of seven syngeneic transplants survived for 60 days and were harvested for histology. Recipients of successful allogeneic transplants (n = 3) received no immunosuppression and rejected their allografts between 8 and 11 days postoperatively. Mixed lymphocyte culture and flow cytometry demonstrated secondary immune responses by pre-sensitized animals, and histology showed lymphocytic infiltration and necrosis consistent with acute rejection.