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Changes in the distribution of nerve fibers immunoreactive to calcitonin gene-related peptide according to growth and aging in rat molar periodontal ligament.

OBJECTIVE
To analyze the age-dependent changes in nerve fibers immunoreactive to calcitonin gene-related peptide (CGRP-ir) in the periodontal ligaments of rats.


MATERIALS AND METHODS
Thirty male Wistar-ST rats were divided into growing groups (5, 9, and 15 weeks of age) and aging groups (6, 12, and 24 months of age) (n = 5 in each group). Eight serial sagittal sections, 5 microm thick, were cut parallel to the distobuccal root of the maxillary right first molar. These tissues were stained with a rabbit monoclonal antibody against CGRP. The observation area was divided into three parts (mesial, apical, and distal) and observed using a light microscope.


RESULTS
CGRP-ir nerve fibers were primarily distributed in the apical periodontal ligament in the growing group, with significantly more fibers than in the aging group.


CONCLUSIONS
CGRP-ir nerve fibers in the periodontal ligament are dense during the growth period and decrease gradually with aging, indicating that CGRP may affect periodontal tissue with growth and aging.