Local injection of nerve growth factor via a hydrogel enhances bone formation during mandibular distraction osteogenesis

ObjectiveThe objective of this study was to evaluate the effects of the injectable NGF-carrying collagen/nano-hydroxyapatite/alginate hydrogel on the bone formation in a rabbit mandibular distraction osteogenesis model.Study designThirty-five New Zealand white rabbits underwent bilateral madibular distraction osteogenesis at a rate of 0.75 mm/12 h for 6 days. The rabbits were divided into 4 groups: group 1 received injections of collagen/nano-hydroxyapatite/alginate hydrogel containing hNGFβ; groups 2, 3, and 4 received injections of hNGFβ, Col/nHA/Alg hydrogel, and saline, respectively. The injections were performed on both sides of the mandible at the end of the lengthening phase. All the animals were killed at a consolidation time of 14 days.ResultsNo difference in regenerate bone dimensions was observed among the 4 groups. Bone mineral density, the maximum load, and the bone volume/total volume of the new bone in the distraction gap in group 1 was significantly greater (P < .05) than in the other 3 groups.ConclusionsApplication of the Col/nHA/Alg hydrogel as an NGF delivery during the consolidation phase of distraction osteogenesis increased regeneration and new bone formation.