Research On The Application Of Mesenchymal Stem Cell Repair Products In The Treatment Of Burns

Objective:（1）Collect and purify secretome during the culture of mesenchymal stem cells,and explore its regulatory effect on endogenous cells and its therapeutic effect on rabbit skin deep second-degree burn.（2）Construct 3D multilayered stem cell skin patches for third-degree burns,and optimize the preparation of decellularized matrix carrier.Methods:（1）Functional testing of dermal fibroblasts by secretome in vitro;injection treatment of deep second-degree burns in rabbit skin to evaluate the therapeutic effect in vivo.（2）Using RAD16-I nanopeptide hydrogels to provide temporary scaffolds for cells to quickly form cells multilayered structure,cultured in a dynamic perfusion system to stabilize the cell sheet structure,and the cell sheet morphology and cell activity were detected after cultivation.Combined with repeated freezing and thawing,ether extraction,and phospholipase A₂ method to prepare decellularized fat to determine decellularized adipose tissue.The efficiency of defatting and decellularization,analysis of the retention of decellularized adipose tissue structure and composition.Results:（1）Secretome can effectively promote the migration of fibroblasts in vitro,and can inhibit their excessive proliferation and transformation into myofibroblasts in the inflammatory environment;the use of secretome for in vivo treatment has a higher wound healing rate and more regular tissue structure.There are obvious endogenous stem cells around the wound.（2）The structure of the stratified cell sheet is stable,and the expression of stem cell markers is normal;the efficiency of decellularized adipose tissue decellularization is 97.3%,and it has a more complete collagen structure after decellularization.Conclusion:The injection of secretome significantly improved the wound quality of skin burns,effectively adjusted the phenotype change of autologous fibroblasts and mobilized the endogenous stem cells around the wound.（2）Three-dimensional dynamic culture system helps maintain cell sheet activity in vitro.It maintains cell sheet activity in vitro;the decellularized adipose tissue defatting and decellularization prepared by the combination method have a higher degree,no cytotoxicity,and the natural structure and ingredients are kept intact.