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Objective To evaluate the viscoelastic properties of porcine acellular dermal matrix (PADM) by comparison and analysis on physical parameters of the skin. Methods Full-thickness skin defects were performed on the back of white rabbits as wound models, and randomly divided these wounds into 3 groups according to different methods of skin grafting: PADM group (autogenous skin and PADM were grafted to the surface of the wound), TS group (autogenous skin was grafted in situ), NS group (normal skin as the control). Experiments on the stress-strain relationship of the implanted skin in the three groups were conducted. Results The curves of stress relaxation, creep, and stress-strain relationship showed that under a given stress, PADM group had the lowest strain, NS group had the highest strain, while the strain of TS group was in between the PADM and NS group. Conclusions The skin viscoelasticity mechanical model is a four-parameter solid model. When the skin wounds are grafted by using PADM which may have poor elasticity, its recovery capacity after deformation is also poor, and this is in agreement with the clinical results.
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Objective To compare the difference of wound healing quality of composite skin grafting consisting of xenogeneic (porcine) acellular dermal matrix (PADM) combined with micro-autograft or split-thickness autograft of skin. Methods Seventy-two Sprague-Dawley rats with full-thickness skin defect on the back were randomly divided into three groups,namely test group I with PADM with split-thickness autologous skin,test group II with HADM with autologous micro- skin and allogeneic skin graft,and control group with autologous micro-skin with allogeneic skin graft to cover the skin defect area respectively. The take rate and the condition of wound healing,and also the rates of wound contraction were calculated. Tissue samples were harvested for histological examination. Results The wound contraction was less in test group I and II than that in control group( P
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Objective To prepare porcine acellular dermal matrix(PADM) without cytotoxicity,to evaluate its biological safety,and investigate its end result in vivo.Methods A piece of porcine split-thickness skin of 0.3-0.4mm was obtained,the epidermis was removed by hypertonic saline immersion,and then the skin was immersed in sodium hydroxide solution,and dermal cells were removed by shaking water bath at normal temperature to harvest PADM.After cross-linking and sterilization,bacteria and porcine virus were examined in the PADM.The PADM were embedded beneath the Sprague-Dawley(SD) rat's skin,and then the general and histological changes were observed after transplantation.Result The obtained PADM was soft and elastic,easy to be moulded,and convenient for operation.No cellular component was found in PADM,the collagen was regularly arranged and elastic fibers were abundant.Bacteria and virus examination of all specimens was negative.No immunologic rejection of PADM was found after being embedded beneath the skin of SD rat.The PADM adhered to the wound firmly,and it was difficult to detach 3 weeks after implantation,and the general structures of PADM beneath rat skin were discernible 24 weeks after implantation.The PADM was infiltrated by inflammatory cells in the early stage,fibroblasts and capillary vessels increased in number along with the time,and collagen fibers gradually gained a regular and compact arrangement in PADM.Conclusions The PADM prepared by hypertonic saline/sodium hydroxide method is a simple preparation process,and there is no cytotoxicity.It has a high biological safety and can be used as dermal scaffold with long-term existence in vivo.