Effects of NGF delivery via a gel in mandibular DO

Objective: To evaluate the effects of hNGF betta delivery via a collagen/nano-hydroxyapatite/k-carrageenan gel to new bone growth and inferior alveolar nerve histology in the rabbit model of mandibular distraction osteogenesis. Methods: 16 New Zealand White rabbits underwent bilateral mandibular distraction osteogenesis at rates of 0.5 or 0.75 mm/12h (8 for each). On the first day of consolidation, the collagen/nano-hydroxyapatite/k-carrageenan gel with or without hNGF betta (20 microgram) was injected into callus percutaneously. The contralateral side received injections of saline. At consolidation time of 14 days, regenerate bone specimens were subjected to bone volume/total volume (BV/TV) analysis and inferior alveolar nerve specimens to nerve fiber density and mean myelinated fiber diameter analysis.A paired t test was used for statistical analysis. Results: The gel/ hNGF betta composite significantly increased BV/TV at distraction rates of 0.5 and 0.75 mm/12h and nerve fiber density at 0.5 mm/12h. New bone and inferior alveolar nerve histology remained unchanged when treated by the gel without hNGF betta. Conclusion: Local application of this gel/hNGF betta composite can accelerate callus maturation and inferior alveolar nerve injury recovery in the rabbit model of mandibular DO, thus providing a possible way to shorten the treatment period and enhance the recovery of inferior alveolar nerve in mandibular DO.