Osteoinductive activity of biphasic calcium phosphate with different rhBMP-2 doses in rats
Dept. of Dentistry/석사
Recombinant human bone morphogenetic protein (rhBMP)-loaded biphasic calcium phosphate (BCP) ceramics, which comprise hydroxyapatite (HA)/beta-tricalcium phosphate (-TCP), can greatly accelerate bone formation. However, few studies have investigated the osteoinductive activity of BMP-loaded BCP with higher ratios of -TCP to HA. The aims of the current study were threefold: (i) to determine whether a HA/-TCP ratio of 20/80 (BCP 20/80) impregnated with rhBMP-2 enhances new bone formation in rat calvarial defects, (ii) to determine the dose-dependent response of rhBMP-2, and (iii) to elucidate the relationship between the amount of newly formed bone and graft degradation in BCP 20/80 at healing intervals of 2 and 8 weeks.Critical-sized calvarial defects were made in rats, which were then allocated to one of the following six groups: (1) sham-surgery control, (2) BCP control, (3) 2.5-μg rhBMP-2/BCP, (4) 5-μg rhBMP-2/BCP, (5) 10-μg rhBMP-2/BCP, or (6) 20-μg rhBMP-2/BCP. The animals were allowed to heal for either 2 or 8 weeks, after which they were sacrificed for histologic and histometric analyses.Histometric analysis showed that the percentages of new bone after 2 and 8 weeks of healing were significantly greater in the BMP-2-treated groups (at all doses) than in the control groups. The percentage of remaining BCP was significantly lower at 8 weeks than at 2 weeks in both the rhBMP-2-treated groups and in the BCP control group, but the amount of new bone was not significantly greater at 8 weeks than at 2 weeks in the 10-μg and 20-μg rhBMP-2/BCP groups.rhBMP-2 administered using a BCP carrier significantly induces new bone formation in the rat calvarial defect model. A dose-dependent response was not shown in the present study, and there appears to be no meaningful relationship between the amount of new bone formation and graft degradation with BCP 20/80. BCP 20/80 may be considered an effective and biocompatible a carrier for rhBMP-2.