糖皮质激素导致股骨头缺血坏死的确切发病机理尚不明确，骨内微循环障碍是最终通路，miRNA-210调控血管内皮细胞VEGF、Notch信号通路对缺血后血管新生发挥重要作用，有望成为一种新的治疗靶点。 本项目研究miRNA-210调控内皮细胞VEGF、Notch信号通路在激素性股骨头缺血坏死中的作用机制；体外将内皮细胞与成骨细胞、破骨细胞进行共培养，在不同浓度激素作用下，观察内皮细胞中miRNA-210的变化规律及其对内皮细胞VEGF、Notch基因、蛋白表达的调控，研究miRNA-210过表达或抑制对调控作用的影响以及与内皮细胞增殖、微血管形成能力、凋亡之间相关性；建立大白兔激素性ONFH模型，研究miRNA-210调节内皮细胞VEGF、Notch信号通路对激素性坏死率、骨结构、血管新生的影响，明确该信号通路在激素性坏死的病理作用机理，探索一种ONFH早期防治的新靶点。

Steroid-induced Osteonecrosis of the femoral head (ONFH) is a debilitating disease that commonly affects young adults between the third and fifth decade of life, which usually results in femoral head collapse, however, its exact pathomechanism remains unclear. Althoug several causes have been involved in the pathogenesis, ONFH occurs through one final common pathway, which is blood interruption. The modulation of endothelial VEGF、Notch pathway by miRNA-210 plays a crucial role in post-ischemic angiogenesis and seems a promising therapeautic target. Angiogenesis, sprouting of capillaries, depends on the proliferation, migration and sprouting of the endothelial cells driven by angiogenic VEGF. This study is to investigate the modulation of the endothelial VEGF、Notch signal by miRNA-210 and its role in the pathogenesis and angiogenesis of steroid induced ONFH in vitro and in vivo. In vitro，enothelial cells are co-cultured with osteoblasts and osteoclasts, the modulation of VEGF、Notch gene and protein expressions by miRNA-210 are evaluated by in situ hybridization, RT-PCR，Western blotting and immunohistochemistry; the effects of miRNA-210 over-expression or inhibition on the endothelial proliferation, migration and capillary formation assay will be fully investigated. In vivo, steroid-induced ONFH is established in a rabbit model, the role of miRNA-210 modulating endothelial VEGF、Notch in angiogenesis of ONFH is investigated in order to find a new effective way to prevent and treat the early stage steroind-induced ONFH.

项目背景：糖皮质激素导致股骨头缺血坏死（ONFH）的确切发病机理尚不明确，骨内微循环障碍是最终通路，miRNA-210调控血管内皮细胞VEGF、Notch信号通路对缺血后血管新生发挥重要作用，有望成为一种新的治疗靶点。主要研究内容：本项目研究miRNA-210调控内皮细胞VEGF、Notch信号通路在激素性ONFH中的作用机制；主要包括：1）在不同浓度激素作用下，观察内皮细胞中miRNA-210的变化规律及其对内皮细胞VEGF、Notch基因、蛋白表达的调控；2）研究miRNA-210过表达或抑制对调控作用的影响以及与内皮细胞增殖、微血管形成能力、凋亡之间相关性；3）建立动物激素性ONFH模型，研究miRNA-210调节内皮细胞VEGF、Notch信号通路对激素性坏死率、骨结构、血管新生的影响。重要结果：本研究发现：1)在激素浓度为10-6mol/L情况下，miR-210表达最高，随着浓度的逐渐提高，miR-210表达下降。MiR-210的表达与内皮细胞VEGF以及Notch基因及蛋白的表达成正相关；2）miR-210过表达可以明显提高内皮细胞的增殖与微血管形成能力；3）我们发现通过一定途径提升动物体内骨组织的miR-210，可以明显上调骨内内皮细胞的VEGF和Notch通路，继而对激素性ONFH的坏死率具有一定保护作用。关键数据及科学意见：除了完成本项目最初设定的内容外，本研究还发现使用药物AZA可以明显提高骨内miR-210的含量，对激素性ONFH具有一定的保护作用，这为寻找治疗激素性ONFH的有效手段提供了新的思路。