Yang Ting, Zhang Jing, Cao Yukun, Zhang Mian, Jing Lei, Jiao Kai, Yu Shibin, Wang Meiqing
State Key Laboratory of Military Stomatology, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, Fourth Military Medical University, Xi'an, China.
Air Force General Hospital, PLA, Beijing, China.
Arch Oral Biol. 2014 Sep;59(9):962-9. doi: 10.1016/j.archoralbio.2014.05.024. Epub 2014 Jun 2.
Subchondral bone loss in mandibular condyles was reported to be induced by experimentally created unilateral anterior crossbite (UAC) which altered the occlusal load distribution and hereafter the temporomandibular joint (TMJ) remodelling process. However, the initial cellular responses are poorly understood. In the present study, changes in osteoblast and osteoclast activities in TMJ subchondral bone were investigated using the rats treated with UAC.
Forty rats were randomly divided into UAC and control groups, and sampled at 2 weeks after the operation. Subchondral bone loss was evaluated by micro-CT. Osteoclast and osteoblast activities were analyzed by real-time PCR. The osteoblast differentiation of the locally isolated BMSCs from TMJ subchondral bone was assessed by Alizarin red staining. The migration of BMSCs was detected by transwell assays.
Compared with the age-matched controls, TMJ subchondral bone loss was observed in the UAC-treated rats (p<0.05). The osteoblast activity evaluated by real-time PCR and osteoblast number revealed by immunohistochemical staining were reduced in the TMJ subchondral bone of UAC rats (p<0.05), and the capability of proliferation, migration and osteoblast differentiation were all decreased in the locally isolated BMSCs from the UAC group (p<0.05).
The present data demonstrated an involvement of reduced BMSCs activity in the initiation of the mandibular subchondral bone loss at the early stage of installation of the aberrant prostheses.
据报道，实验性制造的单侧前牙反合（UAC）会导致下颌髁突软骨下骨丢失，这种情况会改变咬合负荷分布，进而影响颞下颌关节（TMJ）的重塑过程。然而，其初始细胞反应却知之甚少。在本研究中，我们使用接受UAC治疗的大鼠，研究了TMJ软骨下骨中成骨细胞和破骨细胞活性的变化。
将40只大鼠随机分为UAC组和对照组，并在术后2周进行取样。通过微型计算机断层扫描（micro-CT）评估软骨下骨丢失情况。通过实时聚合酶链反应（real-time PCR）分析破骨细胞和成骨细胞活性。通过茜素红染色评估从TMJ软骨下骨局部分离的骨髓间充质干细胞（BMSCs）的成骨分化情况。通过Transwell实验检测BMSCs的迁移情况。
与年龄匹配的对照组相比，接受UAC治疗的大鼠出现了TMJ软骨下骨丢失（p<0.05）。通过实时PCR评估的成骨细胞活性以及免疫组化染色显示的成骨细胞数量，在UAC大鼠的TMJ软骨下骨中均降低（p<0.05），并且从UAC组局部分离的BMSCs的增殖、迁移和成骨分化能力均下降（p<0.05）。
目前的数据表明，在异常假体植入早期，下颌软骨下骨丢失的起始过程中涉及BMSCs活性降低。
