The Study Of Recombinant Human Collagen Hydrogel Containing Fibroblastsin Repairing Skin Defect

Background:Repairing large full-thickness skin defects,which are resulted from trauma,diabetic ulcers,resection of skin cancers etc.,represent great challenges in clinics.At present,the tissue engineeried skin has become one of the most prevalent treatments to repair large skin defect.An ideal tissue engineeried skin,which is fabricated by seeding cells on the scaffold,not only provides a barrier to avoid wound infection and fluid loss,but also promote fibroblasts to secrete various growth factors to facilitate skin regeneration.There are synthetic scaffolds and natural scaffolds,which is the hotspot in the research field.Although the synthetic scaffold has high mechanical strength,good flexibility and easy to be processed,the degradation products from synthetic scaffolds accumulate in the body,and the excretion process is slow.In comparison,the natural scaffold has good biocompatibility and its degradation products are easily metabolized.For example,collagen has been widely used in tissue engineering skin(e.g.Dermagraft,Transcyte and Apligraf).However,the collagen of the tissue engineering skins products is mostly extracted from animal tissues,which have potential pathogen risk and batch-to-batch instability.Recombinant collagen overcomes the shortcomings of potential pathogens and batch-to-batch instability,while maintains the good biocompatibility of natural collagen.Methods and Results:In this study,recombinant human collagen(rHC)was cross-linked with transglutaminase(TG),and mixed with mouse fibroblasts to generate a recombinant human collagen hydrogel(rHC/TG-cell hydrogel)containing fibroblasts for skin defect repair.Firstly,the biological activity of rHC was evaluated by cell proliferation,cell migration and real-time quantitative PCR(RT-PCR)analyses.The results revealed that rHC has good cytocompatibility and can stimulate fibroblasts to secrete various growth factors that promote wound healing.Then,the physicochemical properties of the-rHC/TG hydrogel were examined by using a scanning electron microscope(SEM)and a rheometer.The results demonstrated that the rHC/TG hydrogel has a porous structure and suitable mechanical strength,which can keep loaded cells viable.Finally,the effect of rHC/TG-cell hydrogel on skin defect repair was evaluated by using a mouse skin defect model.The results showed that the rHC/TG-cell hydrogel contributed to the repair of skin defects and achieved skin regeneration in a short time.Conclusion:The rHC/TG hydrogel obtained from cross-linking with TG can load fibroblasts and provide a moist and suitable environment for cells to promote the secretion of growth factors that were required for cell growth,thereby promoting wound healing.It provides the foundation for further clinical application of rHC/TG-cell hydrogel in the skin wound treatment.