Effects Of Systemic Applied Nerve Growth Factor To Mandibular Distraction Osteogenesis In Rabbits

Distraction osteogenesis (DO) has become a widely accepted method in deformities and defects in maxillofacia regions. However, it is still restricted by two issues of inferior alveolar nerve (IAN) injury and the rather long period of bone consolidation time. Nerve growth factor (NGF) is an important growth factor involved in recovery of neurological injuries, and also involved in normal bone metabolism and can enhance bone repair. So the aim of this study was to determine the ability of systemic applied NGF to enhance bone regeneration and recovery of IAN injury simultaneously in a rabbit model of mandibular DO. Three parts were included in this study:1 To evaluate the Sensory Nerve Action Potentials (SNAP) in IAN following mandibular DO in rabbits.Objective:To evaluate the Sensory Nerve Action Potentials (SNAP) in IAN following mandibular DO in rabbits. Methods:12 New Zealand White rabbits underwent the SNAP test using the BL-420F monitoring system. Six of them underwent bilateral distraction osteogenesis with a rate of 0.5mm/12h for 10 days. Immediately after distraction, SNAP test were recorded. The rest of them directly underwent the SNAP test, without DO. Results: Stable SNAP waves were elited in both groups. The amplitude of the evoked potentials and latency was significantly higher and lower respectively in control group than DO group. Conclusion: The IAN function can be accurately detected using BL-420F monitoring system in mandibular distraction osteogenesis.2 Systemic applied nerve growth factor enhances inferior alveolar nerverecovery in a rabbit model of mandibular distraction osteogenesisObjective: To evaluate the ability of systemic applied NGF to enhance the Inferior alveolar nerve recovery in a rabbit model of mandibular distraction osteogenesis. Methods:48 New Zealand White rabbits underwent bilateral distraction osteogenesis with a rate of 0.5mm/12h for 10 days. Immediately after surgery, 0.6μg/d×20d NGF or sodium chloride were intramuscularly injected respectively. Using BL-420F monitoring system, sensory nerve action potentials(SNAP) were recorded before surgery, at the end of distraction, or at consolidation times of 1, 2, 4 weeks. Results: At the end of distraction and after 1 week of distraction, the amplitude of the evoked potentials and latency showed no statistics difference between the NGF and control groups; At the consolidation times of 2, 4 weeks, the amplitude of the evoked potentials and latency was significantly higher and lower respectively in NGF group than control group (P<0.05). At the end of distraction, the appearance of nerve histology and histomorphometry shows a typical Wallerian degeneration, with advanced axonal loss. At the consolidation times of 2, 4 weeks, there are mild Wallerian degeneration, more fibers with myelin, and more regular disposition in NGF gorup. Conclusion: Systematic applied NGF can accelerates IAN function recovery in mandibular distraction osteogenesis.3 Systemic applied nerve growth factor accelerates callus mineralization in a rabbit model of mandibular distraction osteogenesisObjective: To evaluate the ability of systemic applied NGF to enhance callus mineralization in a rabbit model of mandibular distraction osteogenesis. Methods: 24 New Zealand White rabbits under bilateral distraction osteogenesis with a rate of 0.5mm/12h for 10 days. Immediately after surgery, 0.6μg/d×20d NGF and correspondent sodium chloride were intramuscular injected respectively. The rabbits were sacrificed at consolidation time of 2 and 4 weeks for X-ray and histomorphometric. Results: The groups that received NGF presented a greater amount of mineralized bone trabeculae and more regular arrangement when compared to the Control Group in the distracted area. Conclusion: Systematic applied NGF can accelerate callus mineralization in distraction osteogenesis.