蛛网膜下腔出血(SAH)后早期脑损伤的机制甚多，血管平滑肌细胞表型转换以及血脑屏障破坏起着重要作用。我们的预实验结果提示：SAH后重组骨桥蛋白(rOPN)保护血管平滑肌表型的蛋白表达以及血脑屏障。因此，我们提出假说：SAH后经鼻吸入rOPN通过激活整合素信号通路稳定血管平滑肌细胞表型以及血脑屏障起到减轻早期脑损伤的保护作用。我们应用大鼠SAH模型从以下三方面来论证这一假说。第一，应用Western blot、免疫荧光，肌动标记图，vessel painting及印度墨汁造影术等检测SAH后血管平滑肌表型转换及血脑屏障破坏的影响。第二，通过SiRNA干扰及抑制剂检测rOPN稳定血管平滑肌表型及血脑屏障的保护作用及其机制。第三，应用鼻吸这一临床相关的给药方式，检测rOPN产生长期神经功能改善的作用。本研究聚焦转化从分子、细胞、组织以及动物等多层次展开，为SAH病人提供有效的治疗方案。

The mechanisms of early brain injury after subarachnoid hemorrhage (SAH) are various, the phenotype change of vascular smooth muscle cell (VSMC) and the disruption of the blood brain barrier play important roles in the early brain injury. We have observed recombinant osteopontin (rOPN) might preserve smooth muscle cell phenotype proteins and blood brain barrier after SAH in our preliminary data. Our hypothesis is that intranasal administration of rOPN provides protection against early brain injury after SAH by stabilizing smooth muscle cell phenotype changes and blood brain barrier via integrin receptor signaling pathway. The following three specific aims in rats SAH model are proposed to address our hypothesis. Firstly, we determine the effect of phenotype change of vascular smooth muscle cell and the disruption of the blood brain barrier by western blot, immunofluorescence staining, myography, vessel painting and India ink angiogram after SAH. Secondly, recombinant osteopontin (rOPN) is used to determine its neurovascular protection and its mechanism by inhibitors and RNA interference. Thirdly, we use the recombinant osteopontin (rOPN) by intranasal application as a clinically relevant translational therapy to protect against early brain injury and provide long term functional improvements after SAH. From multi-level of molecules, cells, tissues and animals, this translationally-focused study is significant due to its potential to yield an effective treatment for SAH patients.