Tissue-engineered Acellular Dermal Matrix Combined With Bone Marrow Mesenchymal Stem Cells Repair Skin Deficiency

Skin is the biggest organ of human body and covers every portion of it. Skin is able to maintain the homeostasis and to prevent from damaging of microorganism and chemical materials. Extensive defect of skin is one of common and intractable diseases in clinic, people desired to find ways to resolve the problem for a long time. Many factors, such as burns, trauma, refractory skin ulcer and tumor-reductive surgery, usually result in a large area of skin deficiency, which can cause many diseases even death. Therefore, it is very important to treat wound surface. Now, the clinically conventional treatment includes autograft, allograft and xenograft. However, these treatments have their respective defects. The source of autologous skin is very limited and might make new wound surface. Allograft and xenograft could cause immunological rejection and spread diseases, so their application is restricted.Tissue Engineering is a modern subject. It includes a scaffold that provides an architecture on which seeded cells can be organized and developed into the desired organ or tissue prior to implant. Tissue engineered organs can help people to resolve the problem of lack of organs for transplantation. Tissue engineering skin is now the most successful tissue engineering equipment.Many kinds of tissue engineering skin have been put into clinic in many countries,and obtain good result.Stem cells can renew themselves for long periods through cell division, proliferate rapidly and have the remarkable potential to develop into many different cell types in the body. Bone marrow mesenchymal stem cells (BMSCs) belong to adult stem cells. BMSCs has the ability to generate many different cell types. Tissue-engineered Acellular Dermal Matrix is a neotype scaffold material and has good quality in many ways. For example, its histocompatibility is very good.In this paper, we construct tissue engineering skins with BMSCs and tissue-engineered Acellular Dermal Matrix to repair skin deficiency. So it provides a new method to find ideal seed cells of tissue engineering skins and to treat skin deficiency diseases. The experiment contains four main parts:Experiment 1. Effects of supernatant liquid of BMSCs on Proliferation and Collagen Synthesis of Cultured Fibroblasts: Firstly, we collected the supernatants of BMSCs. Cultured Fibroblasts were stimulated with the supernatant liquid of BMSCs. The proliferation and collagen secretion of cultured fibroblasts were measured by MTT and hydroxyproline coloricmetric method. The supernatant liquid of BMSCs can increase fibroblasts proliferation and general collagen secretion.Experiment 2. The construction of tissue-engineered acellular dermal matrix: The fibroblasts were cultivated and amplified in culture medium, and then the amplified cells in vitro were inoculated in collagen gel to form tissue engineering skin. 10 days later, we removed the fibroblasts from tissue engineering skin by engineering technology. The construction of tissue-engineered acellular dermal matrix was observed by SEM and histology. In this way, we can say the framework is favorable.Experiment 3. Construction of tissue-engineered skin with BMSCs and tissue-engineered acellular dermal matrix: BMSCs were separated from bone marrow of SD rat, and purified by combining density gradient centrifugation with adhering method. The cultured cells in great shape were seeded onto the surface of acellular dermal matrix. It was cultured absolutely inside liquid medium for about 12d. In this way, tissue-engineered skin was expected to be constructed in vitro. The cultured cells were observed growing and proliferating well in vitro. With the cells cultured in the acellular dermal matrix, tissue-engineered skin could be constructed in virto.Experiment 4. The transplantation experiment of tissue engineering skin to repair full-thickness skin defect, contrasting with tissue-engineered acellular dermal matrix and blank: Firstly, full-thickness skin defect were prepared on the bank of adult SD rat. Then, we transplantated tissue engineering skin and tissue-engineered acellular dermal matrix to skin wound surface. We observe their developments and their histological changements. Engineered skin has no obvious rejection and improves the quality of the wound repair.