Abstract: Objective To construct cancellous scaffold of calciumphosphate cement （CPC） and hydrolyzed collagen gelatin,and to observe the effect of substance P （SP） on mandibular bone defect repair by using the scaffold.Methods Hydrolyzed collagen gelatin sponge was prepared by acidolysis and lyophilization of the rattail collagen type Ⅰ.Three groups of CPC based scaffolds were prepared by using 8 mm×2 mm mold.Group one was pure CPC scaffold,Group two was compound scaffold of CPCgelatin,and Group three was compound scaffold of CPCGelatinSP.Criticalsized round bone defect of 8 mm diameter was prepared in rabbit mandible.The scaffolds filled in the defects and bone healing were examined by Xray and MicroCT after 12 weeks.Results Electron microscopy showed that the CPCGelatin scaffold had cancellousbone mimic ultrastructure; Animal experiments showed CPCGelatinSP scaffold merged with the surrounding bone in the 12th week,and new bone regeneration inside the scaffold was significantly better than the other two groups.Conclusions The compound scaffold of CPCgelatin has advantages of easy preparing,easy shaping and selfsetting,and its structure is close to cancellous bone.Besides,substance P can promote the bone repair effect of the scaffold in vivo

Key words: substance P, calcium phosphate cement, hydrolyzed collagen gelatin, mandibular defect