Experimental Study Of Regeneration After Reconstruction Of The Burned Denatured Skin

Background To Repair of deep second degree or mixed degree burns especially in functional position is always a challenge facing the burn Medical. Large sheet of split-thickness autoskin or Cultured epidermal sheets grafting with the acellular dermal matrix could be an optinal choice for the management of deep partical thickness burn wound,which reduced scar formation and contracture obviously.But the Allogenetic scaffold materials costs high and biological activity is limited, which were difficult to meet the need of large area transplant.In recent study, recovery of deep burn with the preservation of denatured dermis could restore the appearance and function of the burn wound, which demonstrated that the denatured dermis will recover to normal or close to normal morphology and structure.[2].The research of the reuse of denatured dermis which was discarded after escharectomy becomes the hotspots.Objectiv To develop a method of producing denatured dermal matrix (DDM) and its feasibility of repairing burn wound.Methods The skin of rats partial thickness burn wound was treated with trypsin/triton X-100and DDM (DDM-ld、DDM-3d、DDM-7d) were obtained.The same method obtained acellular dermal matrix(control group).The resulting DDM and ADM was examined macroscopically with gross observation, histological assay, bacteria culture test,biomechanical study, etc.Then the DDM and ADM were embedded subcutaneously in rats and harvested at3,7,14,28post grafting day to investigate the difference of the compatibility and capacity for reconstruction of dermal collagen tissue.Results The DDM was pliable,elastic and ductile.The components cells were taken off completely and collagen fibers of DDM were destructed and its eosnophilia were reinforced. There was no microorganism in DDM and biomechanical properties were semblable(P>0.05).Implant experiment:Gross observation The incision in each group healed well without local swelling and inflammatory response after grafting.The grafts a compact contacts with the wounds.Fibroblasts, neutrophiles and lymphoeytes migrated into the grafts from3post grafting day.1week after implanting, fibroblasts and microvessel developed evidently,but the inflammatory cells were more in the epidermis face than in the derma face in DDM. IL-4、IL-6、 TNF-α、IL-12and TNF-y expression were markedly increased in each group.There was no significant difference between experimental groups and control group(P>0.05).2week after implanting,There were many fibroblasts, microvessel,neutrophiles, lymphoeytesin and A few macrophages migrated into the grafts. At the same time, IL-4、IL-6、TNF-α、IL-12and TNF-y expression reached the highest value. A large number of Capillary formed in grafts. IL-4、IL-6、TNF-α、IL-12and TNF-y expression were down.Conclusion The source of DDM was widely and the preparation was simple.DDM had very low immunocompetence and good biocompatibility,which can induce ingrowth of microvessels and fibroblasts,so it would be advantageous to application in the large area burns afrer reconstructed ex vivo.