中文摘要：

目的：研究实验性单侧前牙反（牙合）（unilateral anterior crossbite,UAC）对大鼠髁突软骨的致病意义及对促软骨细胞分化的CaMKⅡ表达的影响。方法：40只6周龄SD雌性大鼠,随机等分为UAC组和对照组,其中UAC组左侧上下切牙各戴一套筒冠并形成反（牙合）关系,对照组不作处理。于实验开始后4周和8周取材,HE和番红O染色观察髁突软骨的组织形态变化,免疫组织化学染色观察CaMKⅡ的表达,Real-time PCR测量相关基因表达水平的变化。结果：UAC组髁突软骨细胞分化异常,软骨变薄,基质减少,且随时间的延长而加重（P〈0.05）,CaMKⅡ阳性细胞百分数以及CaMKⅡ和Mmp-13的mRNA表达水平上调,但促增殖的Pcna以及软骨基质Col2a1、Aggrecan的mRNA的表达水平下调。结论：UAC可导致髁突软骨异常分化并伴有CaMKⅡ的高表达。

英文摘要：

Objective：To investigate the changes of CaMKⅡexpression level in degenerative cartilage of rats mandibular condylar induced by unilateral anterior crossbite.Methods：Forty 6-week-old SD female rats were randomly and equally divided into UAC（unilateral anterior crossbite）group and the control group.Metal prosthesis was cemented to the left maxilla and mandible incisors of the UAC group rats to create the unilateral anterior crossbite relation.Animals were sacrificed at the end of the 4th or 8th week after stimulation of UAC.Hematoxylin-eosin（HE）and safranin O（SO）staining were carried out for studying the morphological changes of the condylar cartilage.Immunohistochemical（IHC）staining was performed to observe CaMKⅡexpression,and real-time PCR analysis to detect the expression of differentiation and proliferation related genes in condylar cartilages.Results：There was an aberrant chondrocytes differentiation in UAC cartilage.The average thicknesses of condylar cartilage was decreased and SO positive staining area was reduced in UAC group compared with the same period controls and got worse with time.The percentage of CaMKⅡ positive cells was increased.The mRNA expression of differentiation related genes,such as CaMKⅡ and Mmp13,were up-regulated and the proliferation and matrix related genes like Pcna,Col2a1 and Aggrecan mRNA were down-regulated（P〈0.05）.Conclusion：Differentiation was enhanced and the expression of CaMKⅡ was significantly up-regulated in the degenerative condylar cartilage induced by the aberrant occlusion of UAC.