[The change of calcitonin gene- related peptide in periodontal tissue during orthodontic tooth movement].

PURPOSE: To establish a Sprague-Dawley rat model of tooth movement, detect the expression of calcitonin gene-related peptide (calcitonin gene related peptide, CGRP) in Sprague-Dawley rats' periodontal tissues during tooth movement and explore the role of the peripheral mechanisms of pain in orthodontics. METHODS: 60 Sprague-Dawley rats were randomly divided into experimental group (n=54) and control group (n=6). Force was applied on right maxillary first molar in rats and the changes of CGRP expression were detected by real-time PCR 4 h, 8 h, 1 d, 3 d, 5 d, 7 d, 14 d after tooth movement. SPSS 13.0 software package was selected and one-way ANOVA (least significant difference, LSD) was used for statistics analysis. RESULTS: Experimental tooth movement led to an increase in the expression of CGRP. In addition, following experimental tooth movement, the expression of CGRP in periodontal tissues was significantly up-regulated from 4 h, with a peak on 1d and returned to the control level at 2-week. 1 d after experimental tooth movement, the application of different forces to rats induced a significant increase in CGRP expression. CONCLUSION: The regular change of CGRP expression in periodontal tissues indicates that CGRP may play an important role in peripheral mechanism of orthodontic pain.