TRAF6/c-fos在PTH加速兔下颌骨截骨术后正畸牙移动机制的初步研究

目的　研究外源性甲状旁腺激素（PTH）对下颌升支截骨术后正畸牙移动过程中肿瘤坏死因子受体相关因子6（TRAF6）和c-fos mRNA表达变化，探讨PTH加速截骨术后正畸牙移动的调控机制。方法：48只兔建立下颌升支截骨和下颌第一磨牙正畸移动模型，随机分成实验组和对照组。实验组术后间断性注射PTH 40 μg/kg，对照组皮下注射生理盐水，术后测量下颌第一磨牙近中移动速度。HE染色观察正畸牙压力侧组织形态学变化；TRAP染色计数压力侧牙周组织破骨细胞的数目；Real-time PCR检测下颌第一磨牙牙周组织中TRAF6和c-fos mRNA表达变化。结果：实验组下颌第一磨牙近中移动速度快于对照组，且实验组正畸牙压力侧破骨细胞数目较对照组多。实验组正畸牙压力侧牙周组织TRAF6和c-fos mRNA表达均高于对照组（P<0.05）。结论：外源性PTH可通过促进正畸牙压力侧牙周组织中TRAF6和c-fos mRNA表达，促进破骨细胞的成熟和分化，从而加速下颌升支截骨术后正畸牙的移动。

Preliminary study on the mechanism of TRAF6/c-fos in PTH-accelerated orthodontic tooth movement after mandibular ramus osteotomy

Objective To investigate the expression changes of TRAF6 and c-fos mRNA on orthodontic tooth movement after mandibular ramus osteotomy regulated by parathyroid hormone(PTH). Methods Forty eight rabbits were randomly divided into experimental group and control group. An experimental model of mandibular ramus osteotomy with installation of an orthodontic tooth movement device was established. The experimental group received intermittent subcutaneous injections of PTH 40 μg/kg and the control group received injections of normal saline postoperatively. The mesio movement speed of the first molars in the lower jaw was measured after surgery. The histomorphological changes on the compression side of orthodontic teeth was observed by HE staining. The number of osteoclasts on the compression side of periodontal tissue was counted by TRAP staining. Changes in expression of TRAF6 mRNA and c-fos mRNA in the periodontal tissues of the first molars were evaluated by quantitative fluorescence polymerase chain reaction. Results The movement of the first molars was more rapid in experimental group than in control group in the 21 days postoperatively. The number of osteoclasts on the compression side of orthodontic teeth in the experimental group was larger. Significantly higher TRAF6 and c-fos mRNA levels were detected on the compression side of the periodontal tissues in experimental group than in the control group. Conclusions Administration of PTH can increase TRAF6 and c-fos mRNA expression in the compressed periodontal tissues, thereby promoting maturity and differentiation of osteoclasts and accelerating orthodontic tooth movement after mandibular ramus osteotomy.