MAPK信号转导通路影响人工关节无菌性松动的机制研究

Aseptic loosening is the most severe post-operative complication of total joint arthroplasty, since osteolysis is initiated by an aseptic local inflammatory response to proshetic wear debris, leading to osteoclastic per-prosthetic tissue destruction and bone resorption. Cytokines associated with osteoclast differentiation and maturation could regulate critical nuclear gene expression through a variety of signal transduction pathway,including MAPK especially. Our prevous studies have suggested that inhibition of p38MAPK may down-regulate the expression of inflammatory cytokines of wear particles-induced osteolysis,such as TNF-α、RANK/RANKL. In our study, the rat wear particles-induced osteolysis model, the rat RAW264.7 cells and clinical samples were used to detect the expression of MAPK. Then, a quantitative determination was applied to observe how MAPK signaling pathways reduce the expression of TNF-α, IL-1 and RANK / RANKL, and down-regulate the activation and expression of MEK(upstream kinase) and P21ras, and downstream factors such as c-fos, c-jun, ELK-1. The purpose of our study was to explore the molecular mechanisms of regulating periprosthetic osteolysis via MAPK signaling pathway,and to provide a promising mathod for the prevention and treatment of wear particle-induced periprosthetic osteolysis due to aseptic loosening.

无菌性松动是人工关节置换术后最严重的并发症。磨损颗粒激活假体周围炎性细胞因子,进而活化破骨细胞、加剧骨溶解,是无菌性松动重要病因。介导破骨细胞分化成熟各种细胞因子能够通过信号通路调控关键核基因表达，而丝裂原活化蛋白激酶信号通路(MAPK)可能具有重要的研究前景。我们预实验结果表明：抑制p38丝裂原活化蛋白激酶（p38MAPK）可下调磨损颗粒诱导的骨溶解的炎性因子等表达，项目通过构建磨损颗粒诱导骨溶解动物模型、培养小鼠RAW264.7巨噬细胞、收集人工关节无菌性松动临床组织标本对MAPK（p38MAPK、ERK、JNK）进行表达检测；从而对MAPK调控TNF-α、IL-1、RANK/RANKL的表达以及对上游激酶MEK、P21ras和下游转录因子c-fos、c-jun、ELK-1调控表达进行定量检测，全面探讨MAPK下调假体周围骨溶解的分子机制，为人工关节无菌性松动防治寻求最佳治疗靶点。

人工关节置换术是治疗中晚期骨关节疾病最为有效的治疗方法，而人工关节无菌性松动是人工关节置换术后最严重的并发症。人工关节的磨损颗粒激活体内假体周围炎性细胞因子，进而活化破骨细胞、加剧骨溶解，是无菌性松动的重要原因。介导破骨细胞分化成熟各种细胞因子能够通过信号通路调控关键核基因表达，而丝裂原活化蛋白激酶信号通路(MAPK)可能具有重要的研究前景。我们前期实验结果表明：抑制p38丝裂原活化蛋白激酶（p38MAPK）可下调磨损颗粒诱导的骨溶解的炎性因子等表达，本课题项目通过培养小鼠RAW264.7巨噬细胞、构建磨损颗粒诱导骨溶解动物模型、收集人工关节无菌性松动临床组织标本对MAPK（p38MAPK、ERK、JNK）进行形态学与分子生物学实验。结果显示，人工关节无菌性松动的界膜组织中，MAPK影响的Hes1、Hes5、Jagged1, Notch1，TNF-α等细胞介质与炎性因子均有高表达；MAPK抑制剂作用于体外钛颗粒刺激的小鼠RAW264.7巨噬细胞及体内构建磨损颗粒诱导骨溶解动物模型，可以抑制磨损颗粒诱导骨溶解从而引起无菌性松动的MAPK信号转导通路下游因子和激酶TNF-α，MMP-9及RANKL等的表达。因此通过MAPK信号转导通路可以影响磨损颗粒诱导骨溶解导致的无菌性松动的发生发展。本研究通过 MAPK调控人工关节假体周围骨溶解的分子机制深入研究，可为人工关节无菌性松动预防与治疗寻找一种新的方法和途径，也为临床无菌性松动的防控获得最佳治疗靶点。