Immunohistochemical detection of nerve growth factor and its receptors in the rat periodontal ligament during tooth movement.
OBJECTIVE
Nerve growth factor (NGF) and its receptors, p75 and tyrosine receptor kinase A (Trk A), have been shown to increase following trauma. The aims of this study were to examine changes in the detection of NGF and its receptors during orthodontic tooth movement in the rat, and the effects of anti-NGF on these changes.


METHODS
Orthodontic separators were placed between the right maxillary first and second molars of Sprague-Dawley rats which were equally divided into two groups. Animals from the second group were injected with anti-NGF. The left sides served as controls, and animals were sacrificed at 0, 3, 7 and 14 days.


RESULTS
Results of immunohistochemical localisation for p75, Trk A, calcitonin gene-related peptide (CGRP) and NGF showed staining intensity increased at day 3, with a peak at day 7 and decreasing intensity at day 14. Anti-NGF injected animals showed reduced staining at all observation periods.


CONCLUSIONS
Data suggest that orthodontic injury induces NGF production, leading to sprouting and invasion by CGRP-positive nerve fibers and that injection of anti-NGF reduces NGF tissue levels and prevents innervation by CGRP-positive fibers.
O'Hara
Akbar H
AH
Orthodontic Unit, School of Dentistry, The University of Adelaide, Frome Road, Adelaide, South Australia 5005, Australia.
Sampson
Wayne J
WJ
Dreyer
Craig W
CW
Pierce
Angela M
AM
Ferguson
Ian A
IA
D000539:Alveolar Process / Q000166:cytology; D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000032:analysis; D003782:Dental Pulp / Q000166:cytology; D007150:Immunohistochemistry; D008297:Male; D009412:Nerve Fibers / Q000648:ultrastructure; D020932:Nerve Growth Factor / Q000032:analysis* / Q000037:antagonists & inhibitors; D009419:Nerve Tissue Proteins; D009967:Orthodontic Appliances; D010513:Periodontal Ligament / Q000166:cytology*; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D020917:Receptor, trkA / Q000032:analysis; D017978:Receptors, Growth Factor; D017475:Receptors, Nerve Growth Factor / Q000032:analysis*; D014087:Tooth Movement Techniques / Q000295:instrumentation; D014092:Tooth Root / Q000166:cytology
D009419:Nerve Tissue Proteins; D017978:Receptors, Growth Factor; D017475:Receptors, Nerve Growth Factor; C068313:Ngfr protein, rat; D020932:Nerve Growth Factor; D020917:Receptor, trkA; D015740:Calcitonin Gene-Related Peptide