Subcutaneous ectopic osteogenesis induced by porous calcium phosphate cement and gelatin sponge as the carrier of recombinant bone morphogenetic protein-2 in rats: A comparative study

Objective To analyze the difference in subcutaneous ectopic osteogenesis induced by porous calcium phosphate cement（CPC） and gelatin sponge as a carrier of recombinant bone morphogenetic protein-2（rhBMP-2）. Methods Thirty Sprague Dawley rats with an average body weight of 200g were divided into groups A-D.CPC+rhBMP-2,CPC,gelatin sponge+rhBMP-2,and gelatin sponge were implanted into the rats after anesthesia.Ten rats were killed 2,4 and 8 weeks after they were fed under sterile environment.Bone tissue samples were collected from the implantation sites.Tissue mineral density（TMD） and trabecular thickness were detected with micro-CT scanner and analyzed with SPSS10.0 statistical software.Bone tissue was fixed in 4% paraformaldehyde for 2 days,embedded in paraffin,and cut into sections.The sections were stained with H＆E to observe their histological change. Results The tissue mineral density and trabecular thickness of the samples with rhBMP-2 were higher in two experimental groups 2,4 and 8 weeks after implantation,which increased with the prolongation of time（P＜0.05）. Conclusion Porous CPC can be used as a carrier of rhBMP-2 for osteogenesis.