基于Wnt/β-catenin信号通路探讨尿源性干细胞外泌体促进移动性牙根吸收修复的作用机制

Using stem cells to promote the regeneration of periodontal tissue and root repair has been a research hotspot. Previously，the seed cells for periodontal regeneration were mainly derived from periodontal tissue, which often involved surgery, and the quantity of cells was limited. Urine-derived stem cells can be obtained easily and noninvasively. Our previous study found that urine-derived stem cells can promote the proliferation and differentiation of cementoblasts. This study is comprised of in vivo and in vitro parts. In vitro, Urine derived stem cells exosomes(USCs Exo) will be isolated and co-cultured with cementoblasts to induce its osteogenesis and the effects of USCs Exo on the proliferation and differentiation of cementoblasts will be examined. In vitro, first molar root resorption model of rat will be established, and the effects of locally injected USCs Exo on the repair of root resorption lacunae and the expression of cytokines in periodontal tissues will be detected in order to uncover the related mechanism on the molecular level. The role of Wnt/ β -catenin signaling pathway in the proliferation and differentiation of cementoblast cells and the repair of root resorption in rats induced by USCs exo will also be explored.. The study will provide theoretical basis for the treatment of root resorption induced by tooth movement using USCs.

应用干细胞促进牙周组织及牙根再生成为研究热点，以往进行牙根吸收再生的种子细胞主要为牙周组织来源，往往需要通过手术创伤方法获得，其数量少，极大地影响实际临床运用。尿源性干细胞获得较容易且无创。课题组前期实验发现尿源性干细胞能促进成牙骨质细胞的增殖和成骨分化。项目将通过体内外实验进行研究，体外分离尿源性干细胞外泌体（USCs Exo）后，与永生化成牙骨质细胞混合成骨诱导，检测USCs Exo 对成牙骨质细胞的增殖功效和成骨分化的生物学效应。体外建立大鼠上颌第一磨牙移动性牙根吸收模型，局部注射USCs Exo，检测牙根吸收陷窝修复情况，并检测牙周组织中相关细胞因子的表达，从分子生物学层面阐述相关机制。同时探讨Wnt/β-catenin信号通路在USCs Exo促进成牙骨质细胞的增殖和分化以及大鼠移动性牙根吸收的修复过程中的作用。为临床应用尿源性干细胞治疗移动性牙根吸收提供理论依据。

牙根吸收是正畸治疗过程中常见的不良反应之一。本项目对尿源性干细胞促进牙周组织再生和牙根吸收修复做了初步的探讨。研究分为四个部分，第一部分：将尿源性干细胞（USCs）与成牙骨质细胞进行体外共培养，并在体内建立大鼠移动性牙根吸收模型后，局部注射USCs，发现USC能促进成牙骨质细胞的成骨和成牙骨质作用，同时能在体内促进移动性牙根吸收的修复。第二部分：将USCs与牙周膜干细胞（PDLSCs）进行体外共培养，并将USCs诱导后的PDLSCs细胞膜片包裹纳米羟基磷灰石后植入裸鼠背部皮下，发现USCs能在体外促进PDLSCs的成骨和成牙骨质分化，体内能促进PDLSCs膜片在体内成骨和成牙骨质的多向分化。第三部分：体外制备尿源性干细胞外基质（UECM），并将PDLSCs接种于UECM，并将接种PDLSCs的UECM包裹纳米羟基磷灰石植入裸鼠背部皮下，发现UECM能促进PDLSCs的增殖、黏附、铺展和成骨、成血管分化，并在裸鼠体内增强PDLSCs的成骨分化，形成更为致密的胶原纤维。第四部分：尿源性干细胞外泌体的提取和鉴定。综上所述，尿源性干细胞具有促进牙周组织再生及牙根吸收修复的潜力。项目资助发表SCI文章2篇，培养硕士研究生2名。项目投入25万元，支出12.7859万元，剩余经费12.2141万元，将用于该项目的后续研究。