Effect of nerve growth factor and Schwann cells on axon regeneration of distracted inferior alveolar nerve following mandibular lengthening.
OBJECTIVE
To study the effect of nerve growth factor (NGF) and Schwann cells on axon regeneration of the inferior alveolar nerve following mandibular lengthening with distraction osteogenesis.


METHODS
Unilateral mandibular osteodistraction was performed in 9 healthy adult male goats with a distraction rate of 1 mm/d. Every 3 goats were killed on days 7, 14 and 28 after mandibular lengthening, respectively. The inferior alveolar nerves in the distraction callus were harvested and processed for ultrastructural and NGF immunohistochemical study. The inferior alveolar nerves from the contralateral side were used as controls.


RESULTS
On day 7 after distraction, axon degeneration and Schwann cell proliferation were observed, and very strong staining of NGF in the distracted nerve was detected. On day 14 after distraction, axon regeneration and remyelination were easily observed, and NGF expression started to decline. On day 28 after distraction, the gray scale of NGF immunoreactivity recovered to the normal value and the Schwann cells almost recovered to their normal state.


CONCLUSIONS
Gradual mandibular osteodistraction can result in mild or moderate axon degeneration of the inferior alveolar nerve. Nerve trauma may stimulate the proliferation of Schwann cells and promote the synthesis and secretion of NGF in the Schwann cells. Schwann cells and NGF might play important roles in axon regeneration of the injured inferior alveolar nerve following mandibular lengthening.
Department of Oral and Maxillofacial Surgery, Affiliated Hospital, Guiyang Medical College, Guiyang 550004, China.
Zheng-long
ZL
Tang
Jing
J
Hu
Ji-hua
JH
Li
Shu-juan
SJ
Zou
D000818:Animals; D001369:Axons / Q000473:pathology / Q000502:physiology*; D006041:Goats; D007150:Immunohistochemistry; D008297:Male; D008334:Mandible / Q000601:surgery*; D008340:Mandibular Nerve / Q000502:physiology*; D020932:Nerve Growth Factor / Q000502:physiology*; D009416:Nerve Regeneration / Q000502:physiology*; D019857:Osteogenesis, Distraction; D012583:Schwann Cells / Q000502:physiology*
D020932:Nerve Growth Factor