Biological Properties Of Acellular Dermal Matrix Derived From Mature Scar Tissue Versus Normal Skin

Backgroud: Extensive scar repair often requires multiple operations to remove the scar in patients,and the use of excised scar tissue has become the focus of the study of scar repair.Objective: The differences of the acellular dermal matrix between the mature scar tissue and the normal skin were compared in terms of the tissue structure,biomechanics and biocompatibility,and whether it could be used in the process of scar repair was discussed.Methods: Human mature scar tissue and the normal skin were collected and processed into the acellular dermal matrix.After dyeing,the difference of tissue structure between the two groups was observed by light microscope and scanning electron microscope.Then,the universal tensile testing machine was used to do the biomechanical experiments on the stress strain relationship,the differences of stress relaxation,creep and maximum tensile stress.Acellular dermal matrix of the two groups were cultured with fibroblasts respectively,and the growth trend of 10 d cells was observed.Additionally,the acellular dermal matrix samples were placed subcutaneously in the back of SD rats,and the samples were observed at 4,8,12 weeks.The histology and biocompatibility of the two groups were observed and compared.Results and Conclusion: By histological observation,two groups of acellular dermal matrix showed no cellular components;collagen in mature scar acellular dermal matrix is slightly disordered than normal skin,elastin fibers is slightly disordered too.For the biomechanical properties,the stress-strain relationship,stress relaxation,creep and maximum tensile stress in the two groups presented no significant difference,and all the biomechanical curves were in agreement with each other.No significant difference was observed on the cells growth status between the two groups,and the trend of the two groups of growth curves was basically consistent.Animal experiment results: in acellular dermal matrix of mature scar,there was more inflammatory cell infiltration than in normal skin acellular dermal matrix,yet only a small amount of inflammatory cell infiltration;inflammatory reaction in the two groups disappeared gradually with the duration of implantation;at 12 weeks,tissue structure ordered regularly in both 2 groups and small vascular ingrowth was observed.Conclusion: In the aspects of histological observation,biomechanical properties and biocompatibility,there was no significant difference between the acellular dermal matrix of mature scar and human normal skin,and the mature scar can be used for scar repair.