DFCs/PDLSCs复合细胞膜片促进牙周组织再生及再生组织对正畸力反应的研究

Periodontal disease can cause periodontal tissue loss. Tissue engineering technologies based on cell sheets have been commonly used for periodontal regeneration. However, more reports showed that mono-type cell sheet had not yet been developed to regenerate a functional periodontium complex including the root/periodontal complex and periodontal/alveolar complex. As somatic stem cells, periodontal ligament stem cells (PDLSCs) and dental follicle cells (DFCs) are widely used in the field of the complex periodontal regeneration. But，it is unknown whether the contact of these two types of cells can provide an environment which improve the ability of the periodontal regeneration. The purpose of this study was to examine the advantages of using a di-type composite stem cell sheets system containing PDLSCs sheets and DFCs sheets for the regeneration of the complex periodontal structure. PDLSCs and DFCs were isolated and co-cultured in vitro by using transwell chambers. Then,PDLSCs and DFCs sheets were cultured separately, and co-cultured as a di-type composite stem cells (DCSCs) sheet that was further incubated. In addition, we sequentially coated chemical-conditioned root dentin (CCRD) with PDLSCs and DFCs sheets, combined them with ceramic bovine bone (CBB) tubules as the structure of sandwich, and transplanted the composite in immunodeficient mice for comparing the ability of DCSCs sheets group with control group.Next,miniature pig models of periodontal defect and orthodontics treatmet are estabilshed and autologous and the allogeneic (DCSCs) sheets are transplanted to examine the periodontal tissue impairment through clinical assessments,computed tomography (CT) scanning, and histological examination. Finally, we observe the result of impairment and the movement of these teeth with periodontan tissue repaired by di-type composite stem cell sheets and the modification of regenerated alveola. This study contributes to impairment of periodontal defect,transplantation of teeth and the orthodontic movement of these teeth.

牙周病是导致牙周支持组织丧失的主要原因。组织工程方法修复牙周缺损由来已久，以往单一细胞修复组织缺损难以实现复杂牙周组织的再生。牙囊细胞（DFCs）、牙周膜干细胞（PDLSCs）作为牙源性的成体干细胞，广泛应用于牙周组织再生领域。这两种细胞在直接接触的条件下，能否相互诱导，构建出更有利于牙周组织再生的微环境，尚未可知。本课题从提高DFCs、 PDLSCs的干细胞特性及牙周修复效果入手，通过建立DFCs与PDLSCs共培养体系研究两种细胞的相互作用；制备DFCs、PDLSCs细胞膜片以及DFCs/PDLSCs复合细胞膜片，比较三种细胞膜片在体内体外成牙周组织能力；构建小型猪牙周缺损以及缺损修复后正畸模型，植入DFCs/PDLSCs单/复合细胞膜片分析它们修复牙周组织缺损的效果并观察正畸力对修复后牙周组织改建的影响。本研究对于牙周组织缺损的修复、牙齿再植以及修复后牙齿正畸具有重要的临床指导意义。

随着正畸治疗的发展与普及，越来越多的人开始接触并接受正畸治疗。其中成年患者的比例呈现逐年上升的趋势。由于成人患者的口腔状况比较复杂，多种因素导致的牙周支持组织的缺失给正畸治疗带来了相当的风险。目前对于牙周缺损的治疗尚无特效方法，组织工程的方法已是热门成熟技术。.随着各种研究的相继展开，围绕牙周支持组织再生这一课题，不同的种子细胞以及支架材料相继被引入实验研究。牙囊干细胞（dental follicle stem cells，DFSCs）是牙周组织中重要前体的细胞，可分化形成牙周膜等组织结构；牙周膜干细胞（periodontal ligament stem cell, PDLSCs ）是牙周膜中重要的储备细胞。以上两种干细胞均有增殖分化形成并且修复牙周的潜在能力，且具有组织同源性、生物延续性，将其作为种子细胞，通过组织工程的方法进行牙周组织再生的能力一直被众多学者所关注。.本课题组前期关于DFSCs与PDLSCs的共培养研究表明，DFSCs对于健康与炎症来源的PDLSCs的成骨分化有促进作用，于此基础之上构建出一种由DFSCs与PDLSCs共同构建的新型复合细胞膜片，且经过实验证明其在细胞增殖能力、基质分泌量以及组织再生方面均优于传统的单一细胞膜片，但是其体内修复牙周组织缺损及修复后对牙齿正畸的影响尚不明确。.故本研究承接课题组前期研究成果，通过组织工程的方法将比格犬DFSCs与PDLSCs体外增殖，以改良双相磷酸钙（biphasic calcium phosphate, BCP）为支架材料在体外构建组织工程移植物，同种异体植入人工构建的比格犬牙周缺损模型中。并通正畸力牵引再生处牙周组织所支持的牙齿进行移动，通过测量牙齿的移动速率，结合再生组织受力前后的组织学变化，研究再生牙周组织对正畸力的反应与正常组织之间的差异，进而为探讨组织工程再生牙周组织的正畸治疗奠定基础。