Demineralized Dentin Matrix as a Carrier of Recombinant Human Bone Morphogenetic Proteins: in Vivo Study

Abstract

This study aimed to evaluate the efficacy of rabbit demineralized dentin matrix (DDM) as a recombinant human bone morphogenetic protein-2 (rhBMP-2) carrier using the subcutaneous tissues of mice and rabbit calvarial critical-sized defects. DDM of rabbit, combined with rhBMP-2 (DDM/rhBMP-2) was transplanted into the subcutaneous tissues of 6 mice and 6 rabbit calvarial critical-sized defects (DDM = 0.03 g, control; DDM/rhBMP-2 = 0.03 g of DDM, 0.2 mg/ml, 5.0 mu g of rhBMP-2, experimental). Both DDM and DDM/rhBMP-2 was transplanted into the left and right subcutaneous tissues of mice symmetrically. For rabbits, 4 round critical-sized defects (8 mm diameter) were formed on the exposed skull. DDM was transplanted into the 2 defects on the left sides (n = 12) and DDM/rhBMP-2 into the right sides (n = 12). Two animals among 6 mice and 6 rabbits were sacrificed respectively at the 1, 2, and 4 experimental weeks for the histological and histomorphometrical evaluations with hematoxylin and eosin staining. Tissues from rabbits were imaged via micro-computed tomography (mu CT). DDM/rhBMP-2 in mice induced new bone formation at 2 weeks and maturation with bone marrow at 4 weeks. DDM/rhBMP-2 in rabbit calvarium induced new bone formation remarkably at 4 weeks 21.77-47.99% compared to the DDM. These observations suggest that DDM could be considered a potential carrier of rhBMP-2. The rhBMP-2 loaded on DDM enhanced bone formation.