Non-autogenous scaffolds are being increasingly used in repairing craniofacial defects. Bone morphogenic protein-2(BMP-2),has already been well established for its osteoinduction potential. However,currently the only commercially available BMP-2 carrier is the collagen sponge. Collagen sponge has shown to have a fast rate of resorption and suboptimal mechanical strength. Hence the need emerges for a better scaffold for BMP-2 carrier. In this study we compared various scaffolds for their oseteoinduction potential with rh-BMP-2 in athymic rats.
Materials & Methods: 40 Mature, 6wk old Sprague-Dawley athymic rats were divided into 10 groups based on 10 different scaffolds i.e, artelon∗, calcium acetal∗,pro-osteon200(calcium phosphate)∗, pro-osteon200R(calcium Phosphate/calcium carbonate)∗,Kensey Nash I (beta-tricalcium phosphate with polylactic acid),Kensey Nash II & III(TCPwith type I bovine collagen)∗,demineralized bone matrix(DBM) II & I∗( with and without platetet rich plasma). Each group were further subdivided into 4 subgroups based on different BMP-2 concentration (mg/ml) i.e, 0.1,0.05, 0.01 & 0.001. All the scaffolds were placed on the posterior muscular pockets of the rats. Implants were harvested at 6wks . H & E staining in conjunction with polarization was used to identify bone and osteoid. Statistical analysis was performed using two-way ANOVA. Statistical differences were defined at p<0.05.
Results: DBM I & II ,Pro-Osteon 200,and collagen as a group emerged superior to all other scaffolds in promoting osteogenesis(new bone formation:,30.03 ±8.36%, 31.92± 14.23% , 25.33±9.7% 24.50± 8.47%, respectively, P<0.05). DBM promotes osteogenesis equally at all the four concentrations of BMP-2. However the other scaffolds were noted have better osteogenesis at higher BMP-2 concentration.
Conclusion: Newer scaffolds are emerging to be better carriers of BMP-2 than collagen sponge for osteogenesis. DBM has already proven to exhibit a great osteinductive potential but this study shows that it is independent of BMP-2 concentration. This probably could be attributed to already existing BMP-2 and BMP-7 in the DBM itself. Further studies need to be done to analyze the BMP-2 binding capacity of the scaffolds. Of interest to note in this study is that the scaffolds with collagen impregnated were better at osteogenesis than the ones without it.