OBJECTIVETo observe the revascularization process and histological changes in the dermal substitutes after grafting.

METHODSTwenty-one SD rats were enrolled in the study and were randomly divided into swine acellular dermal matrix (sADM), human acellular dermal matrix (hADM), and artificial dermal equivalent (Integra) groups according to different dermal substitutes grafted underneath the skin of SD rats. The gross appearance of the grafts was observed, and the tissue biopsies were harvested at 2, 3, 4, 7, 10, 14, 21, 30, 60, 90, 120, 150, 180 post grafting day (PGD) for the observation of the revascularization process and their histological changes.

RESULTSGross observation: The incision in each group healed well without local swelling and inflammatory response after grafting. The grafts had a compact contact with the wounds. The texture of the grafted dermis in each group was soft and could not be felt from the surface of the body on 90 PGD. The presence of the grafts could be discerned on 180 PGD in all the groups, but some of them became smaller in size and thinner, even hard to identify in a few. Fibroblasts, neutrophils and lymphocytes migrated into the grafts from 2PGD on. New capillary sprouts from the receiving beds could be observed after 3PGD. Affluent capillary nets formed in the grafts during 30 to 60 PGD. The structure of the grafts became nearly unidentifiable from the native dermis after 150 PGDs. Absorption and degradation to various degrees occurred in some of the grafts after 180 PGD.

CONCLUSIONThe revascularization of the three dermal substitutes could begin shortly after grafting. The sponge-like structure of the substitutes was advantageous for the migration of the host fibroblast into the substitute and for the secretion of the new extra-cellular matrix. The dermal substitutes could last in the wound for a long time with partial absorption and degeneration.