Comparison of bone regeneration in a rabbit skull defect by recombinant human BMP-2 incorporated in biodegradable hydrogel and in solution

The objective of this study is to compare bone regeneration induced by recombinant human bone morphogenetic protein-2 (rhBMP-2) incorporated into a biodegradable gelatin hydrogel with that by rhBMP-2 in aqueous solution. After treating rabbit skull defects of 6 mm diameter with the two rhBMP-2 dosage forms, both of them increased the bone mineral density (BMD) at the skull defects with implantation time to a significantly higher extent than a rhBMP-2-free aqueous solution and a rhBMP-2-free empty gelatin hydrogel (p < 0.05). There was no quantifiable difference in BMD between the two dosage forms of rhBMP-2. Histological examination revealed that the integrity of newly generated bone increased with the rhBMP-2 dose, irrespective of the dosage form. The bone defect was filled with regenerated bone 21 days after treatment.