| PURPOSEFacial nerve injury is relatively common in consequence of trauma, temporal bone fracture, surgery for tumors or otitis media, which could lead to deformed appearance and functional incapacitation. In addition, patients' quality of life could be badly ruined. Autologous nerve grafting is the most typically and commonly used in the treatment of neurologic defect. But its clinical result is far from satisfactory owing to nerve displacement, functional defect of donor site, and limited source of donor nerve. Scientists have made great efforts in peripheral nerve reconstruction for years. Under the development of modern science, microenvironment of peripheral nerve regeneration can be rebuilt, and tissue engineered bioartificial nerve graft has become a promising alternative. In this study, we prepared a new kind of biomaterial, porous silk fibroin. It's physical and mechanical property was estimated. The histocompatibility in vivo, and the interaction of cultured Schwann cells with polyporous silk fibroin scaffold in vitro was studied. Polyporous silk fibroin conduits were used in bridging facial nerve defect of SD rats. The feasibility of using polyporous silk fibroin as a kind of novel material in peripheral nerve tissue engineering was evaluated.1. Synthesis and property of polyporous silk fibroin scaffold. Materials and Method: In the present work, we report a new approach to prepare porous scaffolds based on regenerated silk fibroin self-assembling in specialconditions.Result and Conclusion: RSF porous scaffolds were fabricated using a novel method, biomacromolecules self-assembling. RSF porous scaffolds were prepared by a technique integrating mixture solution casting and protein conformational transition in special conditions. With this technique, we were able to prepare RSF porous scaffolds with high mechanical strength and a controllable porous structure. Scaffolds withdifferent geometries shapes can be prepared depend on the geometries of molds, only. The prepared porous scaffolds have highly porosity range 84~98%, controllable pore size 10~350 n m, tensile strength reach 700kPa, elongation to break maximum 100%, the Young's modulus 1.8~8.7Mpa, as well as the general requirement related to the most tissue engineering. The porous scaffold has an interconnected open-pore microstructure. It is possible to control the above-mentioned structural parameters of RSF porous scaffolds and their physical propertied such as mechanical properties for different applications by adjusting the silk fibroin concentration, n-butanol additives, and freezing temperature. In this way, RSF porous scaffolds can be produced under very mild conditions without using any special production apparatus, surfactants, initiator, crosslinking agent, and toxic organic reagent having a fear of adversely affecting the living body.2. Initial study on the histocompatibility of silk fibroin.Material and Method: Porous silk fibroin membrane was buried in subcutaneouspart of the back of SD rat. 2, 4, 6, 8 weeks after operation, general observation andhistological examination was performed.Result: The wounds healed fine after the operation. Only thin connective tissue wrapwas found around SF membrane. Macrophages were observed in tissue section, andfibroblasts and capillary vessel could grow into the interspace of SF membrane. Wefound the border of the scaffold break down at some part 8 weeks postoperatively,while the inside part remained as it was.Conclusion: Porous silk fibroin membrane shows good cell attachment and has goodhistocompatibility. More study should be made on the mechanism and product ofdegradation in vivo.3. Experimental study on facial nerve regeneration by porous silkfibroin conduit.Material and Method: The porous silk fibroin conduit was used in the reconstruction of a 5 mm facial nerve gap of SD rat. Take chitosan conduit as control group. General observation, electrophysilogical study, histological study and image dialysis were performed 2,4,6, 8 weeks postoperatively. Result: The facial nerve of SD rat regenerated successfully as time passed though in...
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