Cancellous Bone Defects Reparation Effect Of Injectable Calcium Phosphate Bone Cement/Magnesium Phosphate Cement/Fibrin Sealant/Bone Morphogenic Protein Artificial Bone In Goat

Bone defect and bone interrupt caused by trauma, infection, and tumor excision is frequently encountered in clinic, and is difficult to deal with it. Recently, with the development of the technology tissue engineering, substituting autoallergic, xenogenic bone graft with bone tissue engineering artificial bone is prone to be used in clinic. Professor Liu , researcher of East China University of Science and Technology, and his coworker have manufactured a new inorganic bone cement- magnesium phosphate cement(MPC) and calcium phosphate cement,(CPC),which is called MPC/CPC. This self solidified, injectable material has good biocompatibility,bone conductibility and bone inducibility, and unlike CPC, it is sufficient in cohere stability. However, its usage is limited in bone tissue engineering, for its poor poring rate, especially large pore. Based on the reports that linear and plane fiber can improve internal spatial structure of CPC, our study simulated the interconnected micro-tubular structure which existences naturally in bone. By the cancellous bone mould of ripe goat condyles of femur, we tried to study the its ability to repair bone defect, it could also give out some theory and experiment data of its usage in clinic. Objective:The objective of this study was to research one kind of injectable bone graft substitute with the advantages of stable osteoinduction, tachy-moulding, biodegradability and vitodynamics strength, by using injectable calcium phosphate bone cement (ICPC)/ magnesium phosphate cement(MPC) / fibrin sealant (FS) as the injectable carrier of bone morphogenetic protein (BMP)。.Methods:1. Determine the clotting time, vitodynamics performance of the 5g bone cement of MPC/CPC which mixed with FS in the dose of 0ml,0.5ml,1ml,1.5ml,2ml. 2. Detecting the clotting time, vitodynamics performance of the composite of MPC/CPC/FS,CPC/FS,CPC, and scaned by Micro CT,detecting the porosity and the micro- characteristic. 3. The composites of MPC/CPC/FS, MPC/CPC, CPC/FS are randomly embedded into the dorsi-muscles of the rabbits, samples are taken at 4 and 8 weeks after the operation, histological test and Micro CT are used to view the biocompatibility and degradation in the organism. 4. Establish the scrotiform coloboma mould of the spongy bone on the condyles of femur of the goats, then the composite of the MPC/CPC/FS/BMP, MPC/CPC/FS are embedded in respectively. Use X-ray,hostological test and Micro CT to detect the density, aera, carrier's degradation and the vitodynamical performance of the new bone, to investigate the capability of material degradation and the bone restoring of the new type MPC/CPC mixed with FS and BMP.Results:1.Solidification time of adding 5g bone cement of MPC/CPC into 1.5ml FS is appropriate to clinical practice,IT:3.49±0.49min;FT:12.15±1.31; Crushing strength:18.09±1.56MPa. Although MPC/CPC/FS 1.5ml decrease the mechanical property, it still fit for the loading part of bone defect repair.2. The porostiy of composite MPC/CPC which was tested by Micro CT is more than the other two group, and outspread grooves and pits are conneted to the micropore of bone cement. 3.MPC/CPC/FS have good biocompatibility and its porosity and grooves and pits connected to micropore of bone cement is increasing step by step with the increase of degration of layers. 4. The composite of MPC/CPC/FS have the specific ability of bone repair. Tests showed that after implanting the composite of MPC/CPC/FS for 12 hours, the artificial bone have partially degraded, and some part of newborn bone have the structure of trabecula which has split, embrace the bone cement; About 24 hours most part of artificial bone has degraded, and they has been replaced by the mature trabecula,lamellar bone and newborn trabecula. AS a result, the bony joints has been formed, and its speed of degradion and ability of bone repair are more than other groups. In addiion, it shows significant difference(P<0.01).Conclusion:Not only the bone repair material of MPC/CPC/FS combined with BMP let the fibrin glue has the ability to sustained release effect to BMP, but also make it has good mechanical property as a carrier. It has the specific ability of bone repair, bone gumminess, degration and biocompatibility. 5. it could be easily fabricated and re shaped, and it has good clinical operability and good mechanical property which can fulfill the needs of loading part. At last, it can testify it is beneficial to clinical bone repair.