Microskin grafting of rabbits with pigskin xenograft overlay

Pigskin xenografts were used to replace allografts in microskin grafting (10:1 expansion ratio) on 15 rabbits. Rabbits were selected randomly for the removal of the overlaid pigskin at days 7, 10 or 14 for the evaluation of the degree of epithelialization. Histological examination of the removed pigskin 7 days after application showed obvious eosinophilic changes in the epidermal cells and pyknotic changes of the nuclei, however in some areas newly formed epidermis could be found. The pigskin became an eschar or slough on day 14. The microskin autografts proliferated and expanded actively under the protection of this overlaid pigskin. The epidermis increased in thickness and with increasing differentiation. The dermal layer was well vascularized with a large number of capillaries and fibroblasts. The wound was covered by the neoepithelium with almost normal skin texture on day 14, by which time the overlaid pigskin became a dry eschar. In areas where the overlaid pigskin was sloughing, the epithelialization of the underlying microskin grafts was not complete at the same time. In these animal studies of microskin grafting, these overlaid pigskin xenografts showed the same effects as those of allografts.