牙囊中含具备多向分化潜能的干细胞，可作为牙再生的种子细胞。牙囊干细胞（DFSCs）的分化需要多种信号通路的相互作用调节，定向诱导DFSCs再生牙一直是近年来的研究热点。本课题组前期研究发现Wnt经典通路可正向调节牙囊细胞(DFCs)的成骨/成牙骨质向分化，采用Wnt基因芯片筛选出DFCs受矿化诱导后Dickkopf-3（DKK3）基因表达明显下调，蛋白印迹实验证实DKK3蛋白表达显著降低。DKK家族是Wnt信号通路的抑制因子，据此推测DKK3可能在DFCs的成骨/成牙骨质向分化中发挥重要作用，DKK3可能成为实现DFSCs诱导牙再生的重要靶点。因此，本课题拟培养分离大鼠DFSCs，用DKK3重组蛋白处理及构建DKK3稳定干扰细胞，观察对Wnt经典通路、增殖和分化的影响，了解DKK3作用的分子机制，并将转染细胞结合PLGA支架移植于SCID小鼠皮下，进一步从体内验证，为调控牙再生提供新思路。

The dental follicle contains multi-lineage potential stem cells, which could be used as seed cells for tooth regeneration. It was reported that numbers of signaling pathways control the dental follicle stem cells (DFSCs) differentiation. Tooth regeneration seems to be always a widely studied topic recently. Our previous study demonstrated that canonical Wnt signaling may promote the osteoblast/cementoblast differentiation of dental follicle cells (DFCs). The Wnt PCR array selected that the expression of DKK3 gene was down-regulated after the mineralized induction to DFCs, and WB results also proved the DKK3 protein level was obviously depressed. Due to the DKK families are inhibitors of Wnt signaling, we speculate that Dkk3 plays an important role in otseoblast/cementoblast differentiation of DFCs, thus may provide a new target for tooth regeneration using DFSCs. This study aims to isolate and culutre rat DFSCs, followed by treatment of recombinant DKK3 or shRNA-DKK3 transfection, to observe their effects on Wnt canonical signaling, proliferation and differentiation. Then the transfected cells combined with PLGA scaffolds will be transplanted to SCID rice, in order to determine the in vivo effect. The study will provide a novel idea for tooth regeneration.