HIF-1α介导的血管化组织工程骨在修复节段性骨缺损中的作用及 AKT/ERK 通路的调控机制

The repair of segmental bone defect (SBD) is one of the major problems faced by the clinical medicine. Tissue engineering technology has been widely regarded as a hotspot for studying the repair of SBD. Previous studies showed that HIF-1α is a key vascular growth factor, and AKT/ERK signal pathway play the role of regulation during the HIF-1α promoting vascularization procedure. Our previous study found that HIF-1α can enhance the aniogenesis and osteogenesis of BMSCs. However, till now, it is not clear whether AKT/ERK signal pathway play regulatory function during above process. Previously, we have successfully repaired critical size defect of rat skull using HIF-1α mediated tissue engineered bone. In view of above data, this work intends to establish the SBD animal models in rabbits and dogs, and to observe the function of HIF-1α mediated tissue engineered bone repairing SBD on 4 different levels (i.e., mRNA, proteins, small animals, and large animals) via lentiviral vector transduction, AKT/ERK signal pathway detection, vascularized tissue bone construction, and dental implant, and to represent regulatory function of AKT/ERK signal transduction pathway. This study will provide the experimental data of using HIF-1α to repair segmental bone defect in the clinic.

节段性骨缺损(SBD)的修复是临床医学面临的难题之一，运用基因增强的组织工程技术修复SBD 成为当前研究的热点。文献报道HIF-1α是关键性血管生长因子，通过AKT/ERK信号通路完成血管重建。我们研究发现 HIF-1α具有促进BMSCs血管及骨向分化作用，然而AKT/ERK信号通路是否起到调控作用尚未明了。前期研究中，我们首次利用HIF-1α介导的血管化组织工程骨对大鼠颅骨标准骨缺损进行了成功修复。鉴于此，本项目拟构建兔桡骨及犬下颌骨SBD动物模型，应用慢病毒载体转染、AKT/ERK信号通路检测、血管化组织工程骨构建及牙种植体植入等技术，从mRNA-蛋白-小动物-大动物4层次观察HIF-1α介导的血管化组织工程骨对SBD的修复作用，并阐明AKT/ERK信号通路在HIF-1α促进BMSCs血管及骨向分化中的调控作用。本项目研究将为临床利用 HIF-1α修复SBD提供理论和实验依据。

HIF-1α介导的血管化作用在骨再生过程中起着重要作用。本研究前期实验发现 HIF-1α具有促进BMSCs血管及骨向分化作用，并首次利用HIF-1α介导的血管化组织工程骨对大鼠颅骨标准骨缺损进行了成功修复。因此，本研究在前期研究基础上构建犬下颌骨边缘骨缺损动物模型，应用慢病毒载体转染、血管化组织工程骨构建及牙种植体植入等技术，从mRNA-蛋白-小动物-大动物4层次观察HIF-1α介导的血管化组织工程骨对边缘块状骨缺损的修复作用。结果发现:（1）过表达HIF-1α的BMSCs中，多种成骨成血管基因及蛋白的表达上调。（2）通过犬下颌骨边缘块状骨缺损动物模型，运用影像学和组织学检查验证了Hif-1α介导的BMSCs可促进缺损骨修复，实现种植体周围骨结合。本项目研究将为临床利用 HIF-1α修复边缘块状骨缺损提供理论和实验依据。