Use of a porcine dermis template to enhance widely expanded mesh autologous split-thickness skin graft growth: Preliminary report

To answer the question whether a xenograft dermal substitute could enhance skin grafting, we used porcine dermis as a template for a widely expanded mesh autologous split-thickness skin (ASTS) graft in a rat model. Four groups of rats had received widely expanded meshed skin autografts to cover an excised back wound. Group 1 had a bed of autologous dermis, group 2 had porcine xenograft dermis, group 3 had widely expanded meshed autograft alone, and group 4 had no graft with the wound healing by contraction alone. Wounds were studied by clinical inspection for texture and contraction, and by histologic and immunofluorescent techniques. At 2 weeks, there was acceptable ASTS graft take, and most of the wound healed completely by 3 weeks. The integrity of this complex skin graft was maintained for 4 months but wound contraction gradually decreased overall wound size. Size was maintained better in the ASTS-autodermis and ASTS-xenodermis groups at postgraft 4, 5, and 6 weeks when compared with the ASTS graft, and there was no difference between the ASTS-autodermis and ASTS-xenodermis groups. Thus both allodermis and xenodermis provided a similar template to enhance widely expanded mesh skin growth and delay wound contraction. The pathologic studies indicate that the xenodermis collagen was replaced either by fibrosis or by biodegradation to rat collagen. The immunofluorescent study also reflected that anti-porcine antibody activity was hugely diminished in the ASTS- xenodermis graft wound after long-term follow-up. In conclusion, either autodermis or xenodermis enhances widely expanded mesh ASTS survival in a rat model, and could significantly maintain the original wound size better than ASTS graft without a template. In a long-term follow-up study, the porcine dermis was replaced either by fibrosis or biodegradation to rat dermis.