A Experimental Study On Synergy Effect Of RhBMP-2and BFGF For Ectopic Bone Formation In Mice

OBJECTIVE To investigate the ectopic bone formation in vivo inducing by therhBMP-2and bFGF composites in mice and to discuss the synergy effect and mechanismof the complex.MATERIALS AND METHODS Twenty-four KM male mice were divided into sixgroups in random: Group A(blank control group), Group B(simple collagen group),Group C(bFGF(2ng)/collagen group), Group D(rhBMP-2(4μg)/collagen group),Group E(rhBMP-2(4μg)/bFGF(2ng)/collagen group), Group F(rhBMP-2(4μg)/bFGF(4ng)/collagen group). The composites were implanted into the muscles of the hind leg of mice,while no implantation in the surgery of blank control group. After two weeks the micewere killed, general observation, concentration of calcium content, Micro-CTthree-dimensional reconstruction scanning with BMD, BVF, Tb.Th and histologicalobservation on hematoxylin-eosin staining&ALP, CD34immunohistochemical stainingwere tested and measured to evaluate the osteogenesis.RESULTS⑴General observation: There wasn’t ectopic bone formation in Group A, B and C. Whileectopic bones could be observed in Group D, E and F.⑵Testing of concentration of calcium content: There were statistically significantdifferences between Group D&E，while the differences was not statistical significancebetween Group D&F and Group E&F.⑶Micro-CT scanning: Three-dimensional reconstruction showed that, in Group D, Eand F, continuous new bone matrixes were mainly located on the outer layer of ectopicbones while there wasn’t substantial bone filling in the center. There were statisticallysignificant differences in BMD, BVF, Tb.Th between Group D&E and in BVF, Tb.Thbetween Group D&F.⑷Histological observation: Hematoxylin-eosin staining showed that, in Group D, E and F, new bone matrixes were mainly located along the edge of the ectopic bones. The effectof osteogenesis in Group E&F was better than in Group D. Immunohistochemicalstaining showed that positive expression of ALP&CD34were mainly located along theedge of the ectopic bones and positive areas in Group E&F was more than in Group D.CONCLUSION RhBMP-2could induce ectopic bone formation alone, while bFGFcould not induce ectopic bone formation alone. There would be a synergy effect forinducing ectopic bone formation with combined application of rhBMP-2and bFGFcomposites.