小胶质细胞TLR4/MyD88/NF-κB通路在睡眠碎片化导致POCD的机制研究

Sleep quality has important effects on learning and memory. The phenomenon of sleep fragmentation(SF) can be frequently observed in preoperative of elderly patients, but the correlation between SF and POCD is currently unclearly. Our previous study has found that the 24h SF could reduce the degree of neuroinflammation, raise TLR4 protein and increase the incidence of POCD. Our previous study has found that the 24h SF could reduce the degree of neuroinflammation, raise TLR4 protein and increase the incidence of POCD. In view of the fact that TLR4 signal is an important target of neuroinflammation, we hypothesize that SF promote the activation of microglia, which reuduces the TLR4/ MyD88/NF-κB signaling pathway of microglia in the hippocampus, and eventually causes excessive neuroinflammation reaction and the incidence of POCD. This project aims to research the correlation in clinic and mice and the regulation mechanism of neuroinflammation between SF and POCD. We firstly illustrate the POCD mechanism of the regulation of the TLR4/MyD88/NF-κB signaling pathway of microglia in neuroinflammation by drug tools and TLR4-/- gene knockout mice. We believe that the results of this project will provide valuable evidences for POCD preventiontion caused by SF.

睡眠质量对学习记忆具有重要作用。睡眠碎片化现象普遍存在术前老年患者，但与术后认知功能障碍（POCD）的相关性目前未有定论。我们前期研究发现：睡眠剥夺24h可导致老年小鼠中枢炎症因子释放增加，小胶质细胞活化和TLR4蛋白上调，及术后海马依赖性认知下降。鉴于TLR4通路在调控炎症反应的重要作用。据此我们提出假说：睡眠碎片化激活小胶质细胞TLR4/MyD88/NF-κB通路调控中枢炎症反应，从而导致POCD发生。本课题拟从分子、细胞、动物以及临床水平等多层次明确睡眠碎片化与POCD的相关性；探讨睡眠碎片化对小胶质细胞活化的调控机制；确定小胶质细胞TLR4/MyD88/NF-κB通路对中枢炎症的调控；揭示睡眠碎片化导致POCD发生的机制。通过工具药、构建TLR4-/-基因敲除小鼠，首次探讨睡眠碎片化激活小胶质细胞TLR4/MyD88/NF-κB通路导致POCD的发生机制，为POCD的防治提供新思路

睡眠质量对学习记忆具有重要作用。睡眠碎片化现象普遍存在术前老年患者，但与术后认知功能障碍（POCD）的相关性目前未有定论。我们前期研究发现：睡眠剥夺24 h可导致老年小鼠中枢炎症因子释放增加，小胶质细胞活化和TLR4蛋白上调，及术后海马依赖性认知下降。鉴于TLR4通路在调控炎症反应的重要作用。据此我们提出假说：睡眠碎片化激活小胶质细胞TLR4/MyD88/NF-κB通路调控中枢炎症反应，从而导致POCD发生。为了验证这一假说，本研究采用多种方法（如脑立体定位注射、分子生物学相关技术、工具药、免疫荧光分析、共聚焦成像以及质粒构建等）从分子、细胞、动物以及临床水平等多层次明确睡眠碎片化与POCD的相关性；探讨睡眠碎片化对小胶质细胞活化的调控机制；确定小胶质细胞TLR4/MyD88/NF-κB通路对中枢炎症的调控；揭示睡眠碎片化导致POCD发生的机制。我们在国家基金委资助下先后完成了动物在体试验及离体水平细胞实验以及临床实验，主要的研究结果如下：（1）睡眠碎片化可引起小鼠小胶质细胞介导的中枢炎症反应及术后认知功能失调；（2）睡眠碎片化通过小胶质细胞TLR4/MyD88/NF-κB调控中枢炎反应，进而参与调控POCD；（3）术前睡眠碎片化与正常睡眠的手术患者的POCD发生发展密切相关。本项目阐明了睡眠碎片化激活小胶质细胞TLR4/MyD88/NF-κB通路导致POCD的发生机制，为POCD新的治疗靶点提供新的方向。