Prolonged survival of reconstituted skin grafts without immunosuppression

Reconstituted skin composed of a cultured allogeneic epithelial sheet (CAES) and a cultured allogeneic dermis (CAD) was evaluated in a rat model to determine whether it could survive for a prolonged period without immunosuppression. Additionally, free CAD grafts were evaluated for their suitability as dermal substitutes. Male Buffalo rats were used as donors and male Lewis rats as recipients. Split-thickness skin obtained from Buffalo rats was separated into epidermis and dermis by means of Dispase II enzyme. The epidermal layers were minced and trypsinized. Then dispersed single keratinocytes were inoculated onto a irradiated 3T3 cell feeder layer. After a suitable period, a confluent cultured keratinocyte layer was detached and provided CAES grafts. Cultured allogeneic dermis grafts were prepared from cultures of the dermal component. Cultured allogeneic dermis grafts, covered by split thickness isografts (STIG) or local skin flaps, became revascularized at a rate of 94.6% and 90.9%, respectively, 7 days after grafting. However, only 25% of CAD grafts covered by synthetic materials became vascularized. Four types of wound coverage were compared including: (1) CAES grafts, (2) CAES over CAD grafts, (3) split-thickness isografts, and (4) STIG over CAD grafts. In groups 2 and 4, CAD grafts were applied 7 days before CAES grafts or STIG. Grafts of groups 1 and 2 were successful in only 36.7% and 31.1% of the animals and resulted in a high rate of wound contracture--72.4%, 66.7%, respectively. On the other hand, in groups 3 and 4, higher average rates of revascularization (92.0% and 88.3%) and lower rates of wound contracture (25.4% and 24.2%) were obtained.(ABSTRACT TRUNCATED AT 250 WORDS)