Comparative Study On Bama Miniature Pig Skin And Its Acellular Dermal Matrix

The skin of domestic animals has been investigated extensively in order to find a suitable experimental model to be used in research studies on human skin.Of all the animals examined pig skin is more similar to human skin anatomically and physiologically.But the domestic pig is not suitable for the biomedicine research for its unsharp genetic background,great individual difference and fast growth velocity.Bama miniature pig,one distinct breed of miniature pigs in China,is an ideal animal model for its high inbreeding degree,genetic stability,small body size.However basic research data of Bama miniature pig is absent,so its application in biomedicine is limited.Acellular dermal matrix used as dermal substitute provides to splite-thickness skin grafts and to cultured epidermal autografts.A thick demal bed at the recepient site inhibits and hypertrophic scar formation of split-tickness skin grafts.The clinic applicationable product of acellular dermal matrix was only originated from human by now.But with the enforcement of laws and regulations about human organ transplantation,the use of tissue or organs originated from human may face the problems of source limitations,ethical issues,law restriction and the risk of infection of HIV or HBV.So utlizing pig acellular dermal matrix as the substitute of human acellular dermal matrix into clinical use will be a potential solution in the future.To accumulate for Bama miniature pig as animal model used in study on human skin and form research basis for Bama minipig acellular dermal matrix in order to utilize it into xeno-transplant in clinical use,skin samples from Bama miniature pigs and human were excised and the morphology,ultrastructre,immnohistochemistry and physico-chemical property of collagen typeⅠextracted from Bama miniature pig skin were studied.Resemblance and disparity between Bama miniature pig skin and human skin were found and described.Then Bama miniature pig acellular dermal matrix was prepared.Its bionomics,safe and efficacy were studied compared to human acellular dermal matrix.The results and conclusions are summarized as follows:1.Bama miniature pig skin were strikingly similar to human skin except it posesses apocrine glands instead of eccrine sweat glands in human skin.4 months Bama miniature pig skin was the most similar to human skin because all layers thickness were similar between Bama miniature pig skin and human skin.Our results indicated that Bama miniature pigs could be used as model for study on human skin,it also could be used as materials to prepare dermal substitute in wound repair.The layer,the layer thickness,the heterogeneity of basal keratinocytes,the dermal-epidermal interface consisted of undulant downgrowths that interdigitated with dermal papillae,the structure and distribution of extracellular matrix,the network of vertically oriented capillary loops that extend into each dermal papilla emanate orom the superficial vascular plexus,were strikingly similar to that seen in humans.The ultrastructure and density of langerhans cell,fibroblast,vascular endothelial cell,mast cell were similar between Bama miniature pig skin and those of human.The reactivity and postive location of the Bama miniature pig skin with anti-human sera to lamilin,fibronectin,filaggrin,collagenⅠ,collagenⅢ,keratin were consistent with human skin.The HPLC chromatograph,UV spectroscopy, amino acids composition,electrophoresis of collgen typeⅠextracted from Bama miniature pig skin showed remarkable similarity to those of human collgen typeⅠ.A significant difference between Bama miniature pig and human was that Bama miniature pig possesses apocrine glands instead of the eccrine sweat glands in human skin.Melanocytes were the next-most prevalent cell type found in human skin,but in Bama miniature pig skin, melanocytes density were various on different areas.Another differences were that Bama miniature pig skin could not react with anti-human sera to CD34,ICAM-1,S-100.2.Bama miniature pig acellular dermal matrix was prepared and the method of preparing was improved.There was no significant difference between Bama miniature pig acellular dermal matrix and human acellular dermal matrix in their histologic structure, antigenicity,biocompatibility,vascularization and efficacy.Our results indicated that Bama miniature pig acellular dermal matrix may be an ideal substitute of human acellular dermal matrix in wound repair.Bama miniature pig acellular dermal matrix treated by 0.25 typsin at 4℃for one night,then treated by 0.5%triton X-100 succussed at room temperature for 12h had no epithelial components and dermal cell components,which could evoke an immune reaction when it is implanted.The prepared acellular dermal matrix remain several extracellular matrix may support cell attachment and proliferation,such as elastic fibre,collagenⅠ,collagneⅢ,collagenⅣ,fibronectin.It exhibited three important properties like human acellular dermal matrix:well biocompatibility,low antigenicity,vapid vascularization.After transplanted to rat's full thickness skin defects in combination with autologous thin split-thickness skin graft(STSG),Bama miniature pig acellular dermal matrix could significantly raise the rate of autologous thin STSG survival and significantly decreace the rate of wound contraction vs only transplant autologous thin STSG group.The effects were not significantly difference between Bama miniature pig acellular dermal matrix and human acellular dermal matrix.So it would be an ideal dermal substitute of human acellular dermal matrix for clinical use.