【作者】 王光；

【导师】 丁寅；

【作者基本信息】 第四军医大学 ， 口腔临床医学， 2008， 硕士

【摘要】 牙周组织结构复杂,由两种硬组织(牙骨质和牙槽骨)及两种软组织(牙龈和牙周韧带)组成。牙周膜干细胞是一种存在于牙周膜中的多潜能成体细胞,能被分离,体外培养增殖,有研究发现牙周膜干细胞能生成牙骨质-牙周膜样复合物,参与了牙周组织的再生。STRO-1是牙周膜干细胞(Periodontal Ligament Stem Cells,PDLSCs)表面抗原标志物之一。作为间充质干细胞表面相对特异标志,STRO-1能够反映出牙周膜干细胞的分布和变化。基于此,本实验选用幼年大鼠进行正畸牙齿移动实验,意在探讨牙周膜干细胞在正畸牙移动过程中的作用及其变化规律。研究分两部分:1、大鼠正畸牙移动模型的建立目的:用大鼠建立牙齿移动实验动物模型。方法:选择SD大鼠35只,随机分为7组,每组5只,一组不予加力,为对照组,其余按加力牵引时间不同分为1、3、5、7、10、14d组。全麻后,以上颌中切牙作为支抗牙,用直径0.2mm镍钛螺旋弹簧对每只大鼠上颌第一磨牙牵引加力50g,到期后处死动物,制备标本。结果:所有实验动物均顺利通过实验全过程,加力过程中,牙齿按设定的方向移动。结论:本研究用大鼠建立的动物模型具有很高的可行性和可重复性。2、大鼠正畸牙移动中牙周组织内STRO-1的分布特征及动态变化目的:观察大鼠正畸牙移动中STRO-1的分布特征及动态变化。方法:大鼠到期后,全身灌注固定,解剖分离出含有第一磨牙及其牙周组织的骨段,标记近远中方向,制备5um厚连续切片,应用HE及EnVision系统两步法染色,行标本组织学观察。每只大鼠选用一张切片,高倍镜下在大鼠牙周膜张力区和压力区分别随机选择一个区域,采用Image-Pro Plus 6.0图像分析系统软件测量出STRO-1表达的平均光密度值(Optical Density,OD)。应用SPSS13.0统计软件采用单因素方差分析(one-way analysis of valance,ANOVA)比较不同时间点加力侧和未加力侧的OD值。结果:对照组牙周膜内显色细胞数量稀少,分布于血管周围,加力3-14d组张力侧、10-14d组压力侧,STRO-1表达强阳性,分布于血管周围,牙周膜牙槽骨交界处,牙周膜牙骨质交界区以及血管外区域。3-14d组张力侧OD值与对照组相比有显著差异,自第3d组开始STRO-1表达强度随施力时间延长有逐渐增高的趋势,7d时达到峰值,自10d组开始至14d组,STRO-1表达强度出现下降趋势,10d、14d组压力侧OD值升高,与对照组相比有统计学意义,且随施力时间延长呈现上升趋势。结论:牙周膜干细胞参与牙周组织的改建过程可能是通过多种机制来实现的。更多还原

【Abstract】 The periodontium is an unusually complex tissue comprised of two hard (cementum and bone) and two soft (gingiva and periodontal ligament) tissues. Periodontal ligament stem cell (PDLSC) contained human PDL is a population of multipotent postnatal stem cells that can be isolated and expanded in vitro. Some findings show that postnatal PDLSCs are clonogenic,highly proliferative cells and capable of regenerating cementum/PDL-like tissues. Consequently,PDLSCs have potential for use in periodontal tissue regeneration.STRO-1 have been identified on a variety of mesenchymal stem cells.So we can identify and localize PDLSC in periodontal ligament using this cell-surface markers. It was very considerable to establish animal model in young SD rats for orthodontic tooth movement and research the roles and the principle of PDLSC.The study consists of two parts:1.Establishment of animal experimental model on orthodontic tooth movementObjective:To establish an animal model in rats for orthodontic tooth movement. Methods:35 young SD rats were used in the study. The rats were randomized into two groups.A coil spring was placed onto the incisor and first premolars in 30 rats.All animals were sacrificed after 1,3,5,7,10,14 days. Specimen was observed histological. Results:All of the animals were alive successfully after the experiment.During the movement the tooth are in prospective direction. Conclusion : The tooth movement was achieved impressively, and it is feasible and repeatable of experimental model on this study.2、The distribution and Changes of STRO-1 in periodontal tissue in rats during orthodontic tooth movementObjective:To observe the distribution and changes of STRO-1 in periodontal tissue in rats and analyze the role of PDLSC in the periodontal tissue remodeling during orthodontic tooth movement.Methods:The model of orthodontic tooth movement was established in young SD rats. The animals were sacrificed after 1,3,5,7,10,14 days. The distribution and changes of STRO-1 in the periodontal tissues of the first molar were observed by immunohistochemistry technology in the section. The optical density(OD)of STRO-1 was analyzed by image-pro plus6. 0 software. Results:Putative stem cells were identified in both normal group and hey were mainly located in the paravascular region. In experimental group ligament clusters of cells were also found in the extravascular region. Wider distributions were detected in sections of experimental ligament. Conclusion:These results indicate that PDLSC participates in the periodontal tissue remodeling during orthodontic tooth movement in multiple ways.更多还原