title: Long-term outcome of xenogenic dermal matrix implantation in immunocompetent rats.
abstract: BACKGROUND
  Acellular dermal matrix (ADM) has been used successfully in the treatment of full-thickness skin injuries as an allogenic dermal substitute. To assess the efficacy of xenogenic ADM in such wounds, we examined the long-term wound healing and immunological responses to porcine ADM in a rat model.
  
  
  METHODS
  Xenogenic and allogenic ADMs were produced by treating porcine (fresh or cryopreserved) or rat skin with dispase and Triton X-100. Full-thickness skin defects on the rat dorsum were implanted with porcine or rat ADMs and overlaid with split-thickness skin grafts (STSGs). Wounds were evaluated grossly and immunologically at 1, 6, and 12 months after surgery.
  
  
  RESULTS
  Extensive wound contraction was seen in wounds implanted with porcine ADM, but healing was significantly (P < 0.01) better in the rat ADM or STSG groups at 6 and 12 months postsurgery. Sera obtained from porcine ADM-implanted rats reacted strongly with porcine ADM and specifically with the papillary dermis and basal lamina. One month postsurgery, extensive inflammation but few intact mast cells were seen in wounds implanted with porcine ADM and significant (P < 0.02) levels of residual porcine ADM were detectable immunologically. Little inflammation was evident in the STSG or rat ADM groups at any time. Significant lymphocyte proliferation (P < 0.05) occurred in the 6- and 12-month groups in response to porcine, but not rat, ADM.
  
  
  CONCLUSIONS
  In wounds implanted with xenogenic ADM, a short-lived acute inflammatory response, long-lasting humoral and cell-mediated immune responses, and generally poor wound healing were observed.
authors.affiliation: Department of Pathology, Cook County Hospital, Chicago, IL 60612, USA.
authors.forename: E Z
authors.initials: EZ
authors.lastname: DeSagun
authors.forename: J L
authors.initials: JL
authors.lastname: Botts
authors.forename: A
authors.initials: A
authors.lastname: Srivastava
authors.forename: M
authors.initials: M
authors.lastname: Hanumadass
authors.forename: R J
authors.initials: RJ
authors.lastname: Walter
mesh_terms: D000818:Animals; D003872:Dermatitis / Q000276:immunology / Q000473:pathology; D020405:Dermis / Q000293:injuries* / Q000473:pathology / Q000601:surgery*; D004195:Disease Models, Animal; D005109:Extracellular Matrix; D007121:Immunocompetence; D008137:Longitudinal Studies; D008214:Lymphocytes / Q000276:immunology; D008297:Male; D008407:Mast Cells / Q000276:immunology; D008422:Materials Testing; D011183:Postoperative Complications / Q000276:immunology; D051381:Rats; D017207:Rats, Sprague-Dawley; D016038:Skin Transplantation / Q000276:immunology; D017768:Skin, Artificial; D013552:Swine; D013997:Time Factors; D014183:Transplantation, Heterologous; D014945:Wound Healing / Q000276:immunology*