Collagenated biphasic calcium phosphate loaded with bone morphogenetic protein 2 in rabbit calvarial defect model

Abstract

Backgrounds and aim of this studyBeing free from any consideration of donor, biphasic calcium phosphate (BCP) blended with hydroxyapatite and beta-tricalcium phosphate has been used as a bone substitutes. In recent years, a cylinder-form collagenated BCP that was incorporated with a type-I collagen matrix have been developed. To overcome the small augmentation by collagen-incorporated scaffolds, recombinant human bone morphogenetic protein 2 (rhBMP2) was treated with the collagenated BCP. The aim of this study was to determine the superiority of the recent collagenated BCP as a BMP2 carrier in healing of calvarial bone defect model in rabbit.Materials and methodsFour circular defects were made in each rabbit calvarial (total 10 rabbits), and materials were delivered as follows: no scaffold (Control), collagen sponge + rhBMP2 (CS), BCP + rhBMP2 (BCP), collagenated BCP + rhBMP2 (CBCP). After 2 weeks and 8 weeks later, samples (n=5) were isolated and stained with hematoxylin and eosin solutions for histological and histomorphometrical analysis.ResultsBCP and CBCP groups exhibited the significantly larger areas of new bone formation, residual scaffold, total augmentation, and total minerals than Control and CS in 2 weeks, and showed similar results also in 8 week even thought there was no significant differences in amount of new bone formation and total augmentation (p<0.05). More importantly, the rates of parameters in CBCP were reached to 85.756±16.85 % in defect closure, to 36.94±8.1% in new bone formation, and to 60.73±6.1% in total mineral until 8 weeks, and these were the highest in all groups even though it was partially significant (p<0.05).ConclusionWe have demonstrated that CBCP group created effective and reliable defect reconstructions in rabbit calvarial model. These results implicate that the moldable cylinder-form collagenated BCP loaded with rhBMP2 might be the practical and convenient biomaterial for bony defect reconstructions.