Hemiface allotransplantation in the mouse

Rat models of experimental face transplantation have been widely used to study vascularized composite tissue allotransplantation. Because the mouse represents a superior species for vascularized composite tissue allotransplantation research, the authors developed a novel surgical technique with which to perform hemiface transplantation in mice. BALB/c hemifacial grafts were transplanted into BALB/c (group 1) or C57BL6 (group 2) recipients (n = 6 per group). Myocutaneous hemiface grafts including a vascular pedicle consisting of the common carotid artery and the external jugular vein were retrieved using superfine microsurgical instruments. The graft was transplanted orthotopically and revascularized using the recipient common carotid artery and external jugular vein for anastomosis applying a non-suture cuff technique. After an initial learning curve, the surgical procedure was performed with a constant and high success rate (78 percent). Operating time was comparable in all groups and lasted 120 ± 15 minutes for the donor and 150 ± 12 minutes for the recipient. All syngeneic grafts survived long term (>100 days). Allograft rejection in group 2 occurred within 14 ± 2 days. Hematoxylin and eosin stains of syngeneic grafts revealed unaltered muscle and skin histology. Allogeneic grafts gradually showed distinct rejection patterns progressing with time and similar to those observed after human face transplantation. This is the first description of a mouse hemiface allotransplantation model. The microsurgically demanding procedure may be used to investigate basic immunology and rejection and to address questions related to nerve regeneration in reconstructive face transplantation.