中文摘要：

目的：探讨牙周膜干细胞（PDLSCs）在正畸牙移动（OTM）中的作用及经典Wnt信号通路对其骨向分化能力的影响。方法：将24只SD大鼠随机分为4组（n=6）,3个实验组用加力装置对其右侧上颌第一磨牙施加近中向正畸力,对照组不加力;加力0、1、3、7 d后牙周组织取材,HE染色观察形态学变化、TRAP染色观察破骨细胞数的变化,免疫组化染色观察nestin和active-β-catenin的表达。分离培养h PDLSCs并将其随机分为3组,实验组给予100 KPa/12 h的静压力刺激,另2组为对照组,分别于0 KPa静压力和低氧条件下培养12 h,Western blot法检测细胞中OPG、RANKL、ALP、Runx2、p-GSK3β、active-β-catenin的表达水平。结果：随着正畸加力时间的延长,移动牙压力侧的牙周膜间隙逐渐变窄、破骨细胞数逐渐增多;牙周膜内nestin和active-β-catenin的表达亦随加力时间而呈逐渐上升（P〈0.05）。Western blot法检测显示,100 KPa/12 h静压力刺激组的h PDLSCs中,p-GSK3β和active-β-catenin的表达水平增加（P〈0.05）,ALP和Runx2的表达水平下降（P〈0.05）,RANKL/OPG比例上升（P〈0.05）。结论：牙周膜干细胞参与正畸牙移动过程,静压力作用可使h PDLSCs中的Wnt信号通路激活,使其成骨活性降低、破骨活性增强。

英文摘要：

AIM ：To investigate the role of periodontal ligament stem cells （PDLSCs）in orthodontic tooth movement （OTM）and the effects of Wnt/β-catenin signaling pathway on the osteogenic differentiation of PDLSCs. METHODS：24 SD rats were randomly divided into 4 groups（n =6）,orthodontic appliance was added in the upper right first molar for 0,1,3,and 7 d respectively.The animals were sacrificed and the histological sections were taken. The morphological changes of periodontal tissues were observed by HE staining.TRAP staining was used to observe the number of osteoclasts and immunohistochemical staining was used to observe the expression of nestin and active-β-catenin in periodontal tissues.Human PDLSCs were cultured and randomly divided into 3 groups.Cells in experimental group were treated with 100 KPa static pressure for 12 h and the controls were respectively treated with 0 KPa static pressure and low oxygen condition for 12 h,respectively.Western blotting was used to test the expression of OPG, RANKL,ALP,Runx2,p-GSK3βand active-β-catenin in each group.RESULTS：With the extension of orthodontic strength time,the periodontal space in the pressure side of orthodontic tooth became narrow and the number of osteo-clasts in the pressure side was gradually increased.The expression of nestin and active-β-catenin in periodontal tissues was increased constantly with time（P ＆lt;0.05）.Western blotting analyses indicated that,in hPDLSCs treated with 100 KPa/12 h static pressure,p-GSK3βand active-β-catenin expression was increased （P 〈0.05）,while ALP and Runx2 expression was decreased （P 〈0.05）and the ratio of RANKL/OPG was increased （P 〈0.05）.CONCLU-SION：PDLSCs play an important role in the orthodontic tooth movement.Wnt/β-catenin signaling pathway is activa-ted under static pressure,hence inhibiting the osteogenic activity and promoting the osteoclastic activity of PDLSCs.