Zhang H Y, Liu Y D, Yang H X, Zhang M, Liao L F, Wan X H, Wang M Q
State Key Laboratory of Military Stomatology, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, The Fourth Military Medical University, Xi'an, China.
J Oral Rehabil. 2015 Sep;42(9):685-92. doi: 10.1111/joor.12304. Epub 2015 May 1.
Temporomandibular joint (TMJ) displays a high remodelling capability. The current purpose was to investigate the differences between mandibular condylar remodelling responses of growing mice to installation and removal of unilateral anterior crossbite (UAC) prosthesis. Twenty-four mice were divided into one mock control group and two UAC groups. Unilateral anterior crossbite was created by installing a pair of prosthesis to left-side maxillary and mandibular incisors. Unilateral anterior crossbite was removed in removal group at 3 weeks but remained in UAC group. Temporomandibular joints were sampled at 7 weeks. Changes in condylar cartilage and subchondral bone were assessed by histology and in vivo micro-CT. Real-time PCR and immunohistochemistry were performed to evaluate expression changes in ADAMTS-5, MMP-3, MMP-9, MMP-13, IL-1, TNF-α, OPG and RANKL. Statistical analysis was performed at α = 0.05. Temporomandibular joint cartilage degradation was induced by UAC as previously reported but was reversed by removal of UAC. The dropped cartilage thickness, chondrocyte number and collagen II-positive area, the increased expression levels of Adamts-5, Mmp3, 9, 13, Tnf-α and Il-1β in cartilage, the decreased ratio of OPG/RANKL in both condylar cartilage and subchondral bone, the loss of TMJ subchondral bone and the increase in the TRAP-positive cells in subchondral bone were all reversed in the removal group (P < 0.05). The growing mouse TMJ condyle displays a high remodelling capability which can be degenerative and rehabilitative, respectively, in response to placement and thereafter removal of the aberrant prosthesis. Eliminating aberrant prosthesis is helpful to promote the degraded condyle to recover.
颞下颌关节（TMJ）具有很高的重塑能力。当前的目的是研究生长中小鼠对单侧前牙反合（UAC）矫治器安装和去除后下颌髁突重塑反应的差异。将24只小鼠分为一个假对照组和两个UAC组。通过在上颌和下颌左侧切牙上安装一对矫治器来制造单侧前牙反合。去除组在3周时去除单侧前牙反合，但UAC组中仍保留。在7周时采集颞下颌关节样本。通过组织学和体内微型CT评估髁突软骨和软骨下骨的变化。进行实时聚合酶链反应（PCR）和免疫组织化学以评估ADAMTS-5、基质金属蛋白酶（MMP）-3、MMP-9、MMP-13、白细胞介素（IL）-1、肿瘤坏死因子（TNF）-α、骨保护素（OPG）和核因子κB受体活化因子配体（RANKL）的表达变化。以α = 0.05进行统计分析。如先前报道，UAC诱导颞下颌关节软骨降解，但去除UAC可使其逆转。去除组中，软骨厚度降低、软骨细胞数量减少、II型胶原阳性面积减少、软骨中Adamts-5、Mmp3、9、13、Tnf-α和Il-1β的表达水平增加、髁突软骨和软骨下骨中OPG/RANKL比值降低、TMJ软骨下骨丢失以及软骨下骨中抗酒石酸酸性磷酸酶（TRAP）阳性细胞增加均得到逆转（P < 0.05）。生长中小鼠的TMJ髁突具有很高的重塑能力，分别可因异常矫治器的放置和随后的去除而发生退变和恢复。去除异常矫治器有助于促进退变髁突的恢复。
