Experimental Research On The Characterization,Osteogenesis And Angiogenesis Of TBC/CS Composite Scaffolds

Objective: The differences in material characterization,osteogenesis and angiogenesis were compared between calcined fetal bovine true bone ceramic(TBC)and chitosan modified fetal bovine true bone ceramic composites(TBC/CS).Methods: The characterization of TBC bone block and TBC/CS composite scaffolds was studied by XRD(X-ray diffraction)analysis instrument,EDX(Energy Dispersive X-ray)spectro-scopy,scanning electron microscopy,Micro-CT and universal material testing machine.The cytocompatibility of TBC bone block and TBC/CS composite scaffolds was investigated by MTT cytotoxicity assay and cell-to-material adhesionexperiment.The osteogenic differentiation of BMSCs on TBC/CS composite scaffolds was evaluated by quantitative detection of alkaline phosphatase(ALP)and RT-PCR detection of osteogenesis-related genes.The osteogenic effect and angiogenesis ability of TBC bone block and TBC/CS composite scaffolds were evaluated by Micro-CT scanning,masson trichrome staining and immunohistochemical staining.Results:(1)XRD and EDX result showed that the main component of TBC bone block was?-TCP when the calcination temperature was 1000 ?,and the Ca/P ratio was close to 1.44±0.03.(2)There was no significant difference in pore size and porosity between TBC bone block and TBC/CS composite scaffolds(P>0.05).(3)The compressive strength and flexural strength of TBC/CS composite scaffolds were higher than those of TBC(P<0.05).(4)The cytotoxicity of TBC bone block and TBC/CS composite scaffolds was 0 grade,but the adhesionrate of BMSCs cells on TBC/CS composite scaffolds was higher than that of TBC bone block in the first four hours.(5)In contrast with TBC bone block group,the expression of ALP protein in TBC/CS group was significantly increased(P<0.05);This shows that CS could promote the expression of BMSCS alkaline phosphatase.(6)Real-time RT-PCR results demonstated that the genes expression of OCN,COL I and OPN in TBC/CS group was significantly higher than that in TBC group(P<0.05).(7)At 4w,8w and 12 w,the percentage of new bone volume: TBC/CS group wasSignificantly higher than TBC group(P<0.05).(8)At 4w,8w and 12 w,the percentage of residual material volume: TBC/CS group>TBC group(P<0.05).(9)At 4w,8w and 12 w,the percentage of neovascularization per square millimeter: TBC/CS group > TBC group(P<0.05).Conclusion: TBC/CS composite scaffold material has a stable physical and chemical properties,perfect cell compatibility,better osteogenic effect and vascular regeneration ability,and it can be used for clinical non-bearing area bone defect repair.