炎性环境下RIP3/caspase-8在牙周膜干细胞介导组织再生中的作用及机制研究

Chronic periodontitis is a disease associated with immune and bone destructive. Recently, studies are focused on inflammatory regulation and bone regeneration by stem cells. With multiple differentiation and immune regulation, the periodontal ligament stem cells (PDLSCs) are the main cells for periodontal tissue reparation and regeneration. Recent studies have found that RIP3/caspase-8 mediated immunity and necroptosis from bacterial infection. In our previous research, we demonstrated that the inhibition of RIP3/caspase-8 reduced IL-1β level and enhanced the vitality of PDLSCs in inflammatory conditions. But, the regulation function of RIP3/caspase-8 on PDLSCs remains uncovered. In this project, we intended to systematically explore the effects of RIP3/caspase-8 on PDLSCs for periodontal tissue regeneration in the inflammatory environment in vivo and vitro. It will provide new strategies and theoretical basis for the prevention and treatment of periodontitis.

慢性牙周炎是与免疫相关的骨破坏性疾病，利用干细胞调节炎性反应并促进骨质再生是治疗该疾病的研究热点。具有多向分化和免疫调节特性的牙周膜干细胞（PDLSCs）是牙周组织修复和再生的主要细胞群。最新研究表明：RIP3/caspase-8调控了细菌感染引起的炎性反应和necroptosis。我们前期实验也发现：炎性环境下PDLSCs高表达RIP3，发生necroptosis，RIP3/caspase-8的抑制有效的降低了PDLSCs中IL-1β水平, 增强了细胞活力。然而，RIP3/caspase-8对PDLSCs具体调控作用及分子机制尚不明确。本课题拟在前期工作基础上，通过细胞及组织再生这两个不同的层次，从体外、体内研究RIP3/caspase-8信号通路对炎症微环境下PDLSCs的生物学特性及牙周再生的影响，为牙周炎的临床预防和治疗提供新的策略和理论依据。

牙周炎的治疗目的是在炎性环境下恢复牙周组织再生。RIP1/RIP3介导的程序性坏死调节了细菌诱导的自身免疫反应。本研究发现在炎性微环境下，PDLSCs高表达RIP1/RIP3，电镜也进一步证实了程序性坏死的存在，RIP3/caspase-8抑制后，PDLSCs经矿化诱导形成的矿化结节和ALP量增多，成骨相关基因（COL1, RUNX-2, BSP, OCN）表达量也增加，ELISA检测炎性相关因子（IL-1β,TNF-α,IL-18），RIP3/Caspase-8抑制后PDLSCs的炎性相关因子表达下降，异位成骨和牙周原位成骨结果均表明RIP3/caspase-8抑制后PDLSCs形成牙周膜/牙槽骨的量增加。本研究阐明了炎性环境下，RIP3/caspase-8调控了PDLSCs的程序性坏死信号通路，抑制RIP3/caspase-8 能有效促进牙周组织再生，为今后研究牙周炎的治疗提供新的策略和理论依据。