Shen Tao, Qiu Lin, Chang Huijun, Yang Yanchun, Jian Congxiang, Xiong Jian, Zhou Jixiang, Dong Shiwu
Department of Stomatology, Southwest Hospital, Third Military Medical University Chongqing, China ; Department of Stomatology, Out-Patient Department of 61251 PLA Troops Qinhuangdao, China.
Department of Stomatology, General Hospital of Beijing Military Area Command Beijing, China.
Int J Clin Exp Pathol. 2014 Oct 15;7(11):7872-80. eCollection 2014.
Orthodontic forces result in alveolar bone resorption and formation predominantly on the pressure and tension sides of the tooth roots, respectively. Human periodontal ligament stem cells (PDLSCs) have demonstrated the capacity to differentiate into osteoblasts, and they play important roles in maintaining homeostasis and regenerating periodontal tissues. However, little is known about how PDLSCs contribute to osteoblastogenesis during orthodontic tooth movement on the tension side. In this study, we applied a 12% cyclic tension force to PDLSCs cultured in osteoinductive medium. The osteogenic markers Runx2, ALP, and OCN were detected at the mRNA and protein levels at different time points using real-time PCR and western blot analyses. We discovered that the mRNA and protein levels of Runx2, ALP and OCN were significantly up-regulated after 6, 12 and 24 hours of mechanical loading on PDLSCs compared to levels in unstimulated PDLSCs (P < 0.05). This study demonstrates, for the first time, the effects of mechanical tensile strain on the osteogenic differentiation of PDLSCs, as examined with a Flexcell FX-4000T Tension Plus System. Our findings suggested that cyclic tension could promote the osteogenic differentiation of PDLSCs. Furthermore, the effects of orthodontic force on alveolar bone remodeling might be achieved by PDLSCs.
正畸力分别主要导致牙槽骨在牙根的压力侧和张力侧发生吸收和形成。人牙周膜干细胞（PDLSCs）已显示出分化为成骨细胞的能力，并且它们在维持内环境稳定和牙周组织再生中发挥重要作用。然而，关于在正畸牙移动过程中张力侧的PDLSCs如何促进成骨细胞生成知之甚少。在本研究中，我们对在骨诱导培养基中培养的PDLSCs施加12%的周期性张力。使用实时PCR和蛋白质印迹分析在不同时间点检测成骨标志物Runx2、碱性磷酸酶（ALP）和骨钙素（OCN）的mRNA和蛋白质水平。我们发现，与未受刺激的PDLSCs相比，在对PDLSCs进行6、12和24小时机械加载后，Runx2、ALP和OCN的mRNA和蛋白质水平显著上调（P < 0.05）。本研究首次证明了机械拉伸应变对PDLSCs成骨分化的影响，该研究使用Flexcell FX - 4000T张力增强系统进行检测。我们的研究结果表明，周期性张力可促进PDLSCs的成骨分化。此外，正畸力对牙槽骨重塑的影响可能是通过PDLSCs实现的。
