大鼠正畸牙移动过程中TRPV1和CGRP在三叉神经节中的表达变化

目的建立SD大鼠正畸牙移动模型,研究牙移动过程中,三叉神经节(trigeminal ganglion,TG)中瞬时受体电位香草酸亚型1（transient receptor potential vanilloid 1,TRPV1）及降钙素基因相关肽(calcitonin gene related peptide,CGRP)的表达位置及表达量的变化规律,进而探讨其在正畸疼痛中的作用机制。方法将66只SD大鼠随机分为空白对照组（6只）、假手术组（6只）和实验组（54只）。建立正畸牙移动模型,实验组大鼠施加50 g力后,分别于4、8 h、1 d（1 d组按力值大小分为1 d-30 g、1 d-50 g、1 d-80 g 3个亚组）、3、5、7、14 d,随机处死6只,切取三叉神经节,采用免疫荧光技术分别检测大鼠三叉神经节中TRPV1及CGRP的表达位置及表达量变化。采用SPSS16.0软件包对数据进行统计学分析。结果免疫荧光染色显示,TRPV1及CGRP主要表达于小型及中型神经元。随着加力时间的延长,三叉神经节中TRPV1免疫反应阳性（TRPV1-IR）神经元百分比及CGRP免疫反应阳性（CGRP-IR）神经元百分比增加,1~3 d相继达到高峰,之后逐渐降低,回落至初始水平,且两者随加力力值增大而呈现增高趋势。结论大鼠正畸牙移动过程中,三叉神经节内TRPV1及CGRP的表达随加力时间及加力力值改变呈现规律性变化,提示TRPV1及CGRP可能在正畸疼痛的发生机制中具有重要作用。

Expression of TRPV1 and CGRP in rat trigeminal ganglion during orthodontic tooth movement

PURPOSE: Sprague-Dawley rat models of tooth movement were established to investigate the expression of transient receptor potential vanilloid 1 (TRPV1) and calcitonin gene related peptide (CGRP) in rat trigeminal ganglion during orthodontic tooth movement, and to explore the roles of TRPV1 and CGRP in orthodontic pain. METHODS: Sixty-six Sprague-Dawley rats were randomly divided into control group (n=6), sham operation group (n=6), and experimental group (n=54). Tooth movement models were established, orthodontic force (50 g) was applied on the maxillary first molar in the rats of experimental group, and then the trigeminal ganglia were collected at 4, 8 h, 1 d (3 subgroups were set up according to the force: 1 d-30 g, 1 d-50 g, 1 d-80 g), 3, 5, 7, 14 d after tooth movement. The changes of TRPV1 and CGRP expression were detected by immunofluorescence staining. SPSS16.0 software package was used for statistical analysis. RESULTS: According to immunofluorescence staining, the TRPV1-IR and CGRP-IR neurons were mostly small to medium sized. The percentages of TRPV1-IR and CGRP-IR neurons in trigeminal ganglion increased after applying force, and reached the peak at 1-3 d and then fell to the initial level gradually. In addition, the application of greater force during experimental tooth movement induced higher percentages of TRPV1-IR and CGRP-IR neurons in trigeminal ganglion. CONCLUSIONS: Experimental tooth movement leads to the regular changes of TRPV1-IR and CGRP-IR neurons in trigeminal ganglion, indicating that TRPV1 and CGRP may play important roles in orthodontic pain.