基于牙周微环境调节的牙周组织再生研究

Regeneration and reconstruction of periodontal tissues are most important and difficult issues in clinic therapy. Periodontal ligament stem cell (PDLSC)-based tissue engineering is the one of directions of periodontal therapy. Until now, the instability of therapeutic effects limited the application of tissue engineering, and the critical negative factors are unclear. Based on our previous studies, we propose to investigate the critical role of periodontal microenvironment on the periodontal tissue reparation and reconstruction in PDLSC-based tissue engineering, and try to find the new clinic therapeutic to improve the effects of cell-based periodontal tissue engineering via host periodontal microenvironment. Several periodontal bacteria (including periodontal pathogenic bacteria and beneficial bacteria) were selected and cocultured with mouse gingiva mesenchymal stem cells (GMSCs) and actived T cells in vitro. The influences of different periodontal bacteria on GMSCs and T cells were observed, and the critical factors to control the capability of periodontal tissue healing and bone regeneration would be dissected, and mechanism would be investigated in detail. The mouse periodontitis models would be used to confirm the critical factors and the mechanism. In order to confirm the mechanism which had been found from mouse periodontitis model, a stable periodontitis bone defect models would be established on the rat maxillary first molars, and PDLSCs would be harvested and cultured from rat periodontal ligament tissues. To repair and reconstruct periodontal tissues, autogenic or allogenic PDLSCs combined with gelfoam were hired to fill into the position of alveolar bone defect. The therapeutic methods to modulate the microenvironment (including bacteria components and host immune system) would be applied on these rat models. The reparation and regeneration effects of periodontal tissues would be evaluate via histological and immunohistological methods, X-ray and MicroCT images. The results may provide the important insight for the clinic therapy of periodontal diseases and cell-based periodontal tissue engineering, and the critical role of periodontal microenvironment during tissue engineering will be highlighted in the flied of periodontal tissues regeneration.

基于干细胞的牙周组织再生是口腔科学的研究重点之一，目前调控因素不清，再生效果不稳定，限制其应用前景。宿主免疫系统新近被证明是制约组织工程修复的重要因素之一，而牙周微环境由于受到牙周微生物的影响更加复杂。本转化医学课题基于前期关于宿主免疫在组织工程中发挥重要作用的研究基础，进一步探讨牙周微生态、干细胞及宿主免疫之间的相关关系，并通过牙周微生态调节和宿主免疫干预促进基于干细胞的再生效果。本课题拟利用小鼠及大鼠为实验动物模型，通过体外共培养系统研究牙周微生态系对牙周干细胞及宿主免疫的影响，发现关键调控机制，并在大鼠牙周再生模型上进行验证，进一步探讨通过调节牙周微生态系及宿主免疫，促进基于牙周干细胞的牙周组织缺损再生的方法。本申请研究有望发现在干细胞介导牙周骨缺损修复中，牙周微生态及宿主免疫调节的关键机制及有效干预手段，为组织工程技术成功应用于牙周再生提供新策略及科学依据。

基于干细胞的牙周组织再生是口腔科学的研究重点之一，目前调控因素不清，再生效果不稳定，限制其应用前景。宿主免疫系统新近被证明是制约组织工程修复的重要因素之一，而牙周微环境由于受到牙周微生物的影响更加复杂。本转化医学课题基于前期关于宿主免疫在组织工程中发挥重要作用的研究基础，进一步探讨牙周微生态、干细胞及宿主免疫之间的相关关系，并通过牙周微生态调节和宿主免疫干预促进基于干细胞的再生效果。主要内容围绕：（1）牙周微生态对宿主免疫应答的影响及其调控机制。（2）牙周微生态对牙周间充质干细胞调控机制的研究。（3）基于牙周微生态调节及免疫调节，促进牙周组织骨缺损再生的方法研究。主要发现，在口腔微生态失衡的环境下，在口腔软组织损伤修复中起重要作用的口腔牙龈及腭部间充质干细胞的功能受损，口腔软组织愈合速度明显减慢，虽然口腔整体菌群数量减少，但局部组织LPS含量增加，从而通过LPS/mir21/Sp1/Tert影响牙龈干细胞增殖能力。同时我们发现细菌的主要炎症因子 LPS 在不同浓度时对巨噬细胞的分化及免疫调节功能不同，提示在不同炎症阶段及炎症状态炎症因子在调节免疫细胞功能上有重要作用。研究结果还发现microRNA-21能直接促进BMMSCs成骨，这一过程部分受到Smad7-Smad1/5/8-Runx2通路的调控。为进一步研究小分子RNA如何介导干细胞介导的组织再生提供依据。研究成果有助于发现在干细胞介导牙周骨缺损修复中，牙周微生态及宿主免疫调节的关键机制及有效干预手段，为组织工程技术成功应用于牙周再生提供新策略及科学依据。发表基金标注相关SCI文章11篇。总影响因子约44.669。

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