Allogeneic microskin grafting of rabbits' skin wounds

Allogeneic microskin grafts (expansion ratio of 10:1), overlain with Biobrane, were applied to 30 rabbits. There were two groups. In group I, the allogeneic donor microskin grafts were transplanted without specific management. In group II, the donor skin was treated with ultraviolet (312 nm) irradiation to depress Langerhans cells immediately before the transplantation. Histological examination of these grafted wounds in the early stage showed that these micrografts proliferated actively with increased mitotic figures and became regularly stratified under the conditions provided by the Biobrane. By day 9, these wounds in group I were almost resurfaced with neoepithelium. In group II, the rate of regeneration of the neoepithelium was slower than those of group I. Subsequently there was rejection with moderate mononuclear infiltration, hydropic degeneration and satellite necrosis of basal and suprabasal keratinocytes, and local destruction of epithelium. Grossly these reactions caused 'melting' of the neoepithelium and resulted in raw areas. These rejections were more severe about 2 weeks after transplantation and then subsided gradually. Mild cellular infiltration continued to prevent the formation of rete ridges and the dermoepidermal junction was smooth at all times. Langerhans cells could not be found in these grafted wounds using OKT-6 and S100 stain. In spite of the destruction caused by these rejections in both groups, 25 wounds were completely resurfaced with well-differentiated neoepithelium by day 21. This study revealed that the transplanted allogeneic microskin grafts could proliferate to form neoepithelium and resurface the skin wounds of rabbits.