Recombinant bone morphogenetic protein-2 and platelet-derived growth factor-BB for localized bone regeneration. Histologic and radiographic outcomes of a rabbit study.

Abstract

Improvement in localized bone regeneration is needed to avoid the use of autogenous tissue. For that purpose, the use biologic mediators was proposed. The aim was to test whether or not one of two biologic mediators, recombinant human bone morphogenetic protein-2 (rhBMP-2) or recombinant platelet-derived growth factor (rhPDGF-BB), is superior to the other and to control groups for localized bone regeneration. Four cylinders (height: 5mm; diameter: 7mm) were screwed on the parietal and frontal bones at the cranium in 12 rabbits. The cylinders either received (i) deproteinized bovine bone mineral (DBBM) mixed rhBMP-2 (DBBM/BMP-2), (ii) DBBM mixed with rhPDGF-BB (DBBM/PDGF), (iii) DBBM (DBBM), and (iv) empty control (control). Rabbits were euthanized at 2and 8weeks (n=6, respectively). Conventional histomorphometric and micro-CT analyses were performed. Parametric linear mixed models were applied for the analyses with Bonferroni correction for the multiple group comparisons. The area of bone regeneration (histology; AAHisto ) at 2weeks peaked for DBBM (41.91%) with statistically significantly greater values compared to DBBM/PDGF and the control group (P<0.05). At 8weeks, mean AAHisto values were 96.29% (DBBM/BMP-2), 46.37% (DBBM/PDFG), 39.66% (DBBM), and 35.98% (control) (DBBM/BMP-2 vs. all groups (P<0.05)). At 8weeks, bone regeneration was greatest for DBBM/BMP-2 (35.62%) with statistically significant differences compared to all other groups (P<0.05). The area of bone regeneration (micro-CT; AAm-CT ) at 2weeks amounted to 43.87% (DBBM/BMP-2), 42.81% (DBBM/PDFG), 48.71% (DBBM), and 0.96% (control). The control group demonstrated statistically significantly less AAm-CT compared to all groups (P<0.05). At 8weeks, mean AAm-CT values were 63.65% (DBBM/BMP-2), 50.21% (DBBM/PDFG), 44.81% (DBBM), and 4.57% (control) (P>0.05). The use of rhBMP-2 significantly enhanced bone regeneration compared to all other groups including the group with rhPDGF-BB.