RESUMO
BACKGROUND: Collagen membranes have been developed to overcome the problem of limited availability of skin grafts. Vascularization and restricted functional epithelization limit the success of bioartificial constructs. OBJECTIVE: To compare the vascularization, epithelization, and integration of a porcine collagen I/III membrane with that of split-thickness skin grafts on skin wounds. MATERIALS AND METHODS: In 21 adult pigs, full-thickness skin defects on the rear side of the ear healed by split-thickness skin grafting, by covering with the membrane, or by free granulation. Skin samples on postoperative days 1, 3, 7, 14, 21, and 28 were evaluated histologically (hematoxylin-eosin, Sirius Red) and using immunohistochemistry (cytokeratin 5/6, transforming growth factor beta receptor (TGFbetaR-III) and immunoblot (TGFbeta(1,3), Smad2/3). Epithelial thickness and TGFbetaR-III-positive capillary area were quantitatively assessed. RESULTS: Epithelization and vascularization in the membrane group were not significantly different from in the group treated with a split-thickness skin graft. Free granulation showed significantly slower epithelization and vascularization (p<.05). TGFbeta(1) and Smad2/3 complex expression were high during free granulation. Matrix was distinguishable until day 7. CONCLUSIONS: This membrane serves as a suitable full-thickness dermal substitute, because the membrane is vascularized faster than free granulation tissue and enables early epithelization.