Transplantation of long-term cryopreserved allocutaneous tissue by skin graft or microsurgical anastomosis: experimental studies in the rat.

A step-wise method of freezing cutaneous soft tissue containing vessels to -196 degrees C for permanent preservation was developed. The methods of embryo cryopreservation were modified for soft-tissue preservation. Cutaneous tissue obtained from the abdominal wall of a Lewis rat was preserved for more than 3 weeks by this method and was then transplanted to a Brown Norway rat with the largest difference in major histocompatibility complex. Rejection reaction against the epidermal layer was markedly delayed, followed by a decrease in antigenicity of the dermis, with survival of the majority of the tissue for more than 6 months. A concept of artificial skin was formed based on these experimental results. A skin flap from the abdominal wall with a vascular pedicle consisting of the femoral artery and vein was similarly preserved and transplanted by vascular anastomosis. This transplant was made viable over a long period through the additional use of an immunosuppressant. Replantation of a rat hindleg also was successfully accomplished by using a skin flap from the abdominal wall with a vascular pedicle consisting of the femoral artery and vein, which had been cryopreserved for more than 3 weeks. These results with 65 pieces in five different treatment groups indicate the reliability of this method of preservation in maintaining the tissue in a state adequate for transfer without loss of viability over a long period. The applicability of this method of allograft preservation to the field of free-tissue transfer combined with microsurgical technique may introduce a new concept to the field of reconstructive surgery in the future. According to the results of the present experiment, the great potential for clinical application is described for the deepithelialized cryopreserved allocutaneous flap transfer.