The Experimental Study Of An Injectable Composite Graft Which Imitating Cancellous Bone

1. Biocompatibility of natural coral and allogeneic demineralized bone matrixAbstract Objective To assess biocompatibility of biomaterials including nature coral and allogeneic demineralized bone matrix. Method Tissue reaction was assessed by implanting materials in vivo for 1, 2 and 6 weeks. And after culturing bone marrow stroma cell combined with different biomaterials 48,96 hours later in vitro,cell morphology and proliferation were observed by invert microscope and MTT respectively. Results None of materials caused inflammation and rejective reaction in vivo. Nature coral did not have significant effect on cell growth ;while mineralized bone matrix increased it (P<0.01) .Conclusion The results showed thatboth nature coral and allogeneic demineralized bone matrix had satisfactory biocompatibility.2. The experimental study on ectopic osteoinduction of an injectable compositegraft which imitating cancellous boneAbstract Objective To evaluate the osteoinductive potential of an injectable bone substitute consisting of natural coral(NC),allogeneic demineralized bone matrix (DBM) and autogeneic marrow (AM). Method Composites of NC/DBM/AM, NC/DBM, NC/AM> and NC alone were injected subcutanously in rabbits back.Specimens were X-Rayed, evaluated histologically and analyzed for alkaline phosphatase(ALP)at 2 and 4 weeks postimplantion.Results Implants of NC/DBM/AM imitating cancellous bone induced new bone effectively and contained significantly higher level of ALP compared with the others (P<0.01) .Grafts of NC/DBM and NC/AM stimulated litter osteogenesis while NC showed no sign of new bone formation. Conclusion Injectable composite of NC/DBM/AM exhibitted excellent osteoinductive activity and might be a valuable bone substitute. 3. The experimental study on imitating cancellous bone composite of naturalcoral ,allogeneic demineralized bone matrix and autogeneic marrow in injectingand repairing craniotomy defectsAbstract Objective To evaluate the potential of an injectable bone substitute imitating cancellous bone, consisting of natural coral(NC),allogeneic demineralized bone matrix (DBM)and autogeneic marrow(AM) in repairing craniotomy defects. Method 27 rabbits were divided into 3 groups and each of them underwent craniotomy with creation of a critical-size defect (15 mm in diameter). The defects were either respectively filled with composite of NC/DBM/AM and NC by injection or left empty. Specimens were X-Rayed, evaluated histologically and analyzed with histomorphometry, SEM at 1, 2 and 3 months postoperation. Results Both radiological and histological examination results showed that implants of NC/DBM/AM induced new bone earlier and more at the defect compared with the others(P<0.01) .Furthermore, the new bone has rich Half system such as bone lacuna and bone canaliculus. By SEM, bone ultrastructure can be observed .Conclusion Composite of NC/DBM/AM imitating cancellous bone enhanced bone formation in repairing rabbits craniotomy defects and exhibitted excellent osteoinductive and osteoconductive activity. The injectable substitute might be a valuable bone substitute. 4. The experimental study on imitating canceDous bone composite of natural coral ,allogeneic demineralized bone matrix and autogeneic marrow in injectingunder subperiosteum of craniumAbstract Objective To observe subperiosteal osteogenesis of an injectable bone substitute consisting of natural coral(NC),allogeneic demineralized bone matrix (DBM) and autogeneic marrow (AM). Method Composites of NC/DBM/AM and NC were injected on rabbits cranium subperiosteally. Specimens were evaluated by eyes,X-Ray, histology and analyzed with histomorphometry at 8 weeks postimplantion.Results Implants of NC/DBM/AM imitating cancellous bone induced new bone effectively and got significantly higher level in height compared with the NC (P<0.01) .Conclusion Injectable composite of NC/DBM/AM exhibitted excellent osteogenesic activity and might be a valuable bone substitute in reconstructing rest alveolar.