凝血酶在脑室出血后脑积水形成中的作用及机制研究

Hydrocephalus after intraventricular hemorrhage (IVH) is a common and major complication that causes clinical deterioration and affects recovery. Treated only with external ventricular drainage is not improved the outcome of IVH patients.Our previous studies demonstrated that thrombin contributes to hydrocephalus development after IVH,but the mechanisms are still not clear. The ependyma is a simple ciliated epithelium that lines the ventricular surface and mainly maintained by adherens junctions. Animal studies demonstrated defects in ependymal adhesion can cause severe hydrocephalus. Our previous studies also found that thrombin induced hydrocephalus are associated with the loss and damage of ependyma. Thus we speculated that disruption of adherens junctions in ependyma caused by thrombin could be the important mechanism of hydrocephalus after IVH. This study will further use of the IVH rat model, ependymal cell culture, combined with the PAR-1, Src, PAK1 and VE-cadherin knockout transgenic mice. In order to clarify the role of thrombin in hydrocephalus after IVH and confirm whether the PAR-1-Src-PAK1 signaling pathways is the mechanism for thrombin induced adherens junctions damage. Successful completion of this study will contributes to understanding the pathogenesis of IVH and develop new therapeutic strategies for hydrocephalus after IVH.

脑室出血后继发脑积水是导致病人临床症状恶化的重要原因，单纯减轻脑积水未能改善预后，我们前期研究显示凝血酶在脑室出血后继发脑积水中起到了非常重要的作用，但是其作用机制至今未明。脑室周边室管膜细胞主要由粘附连接连接而成，动物研究表明粘附连接缺乏会导致严重的脑积水，我们前期研究也发现凝血酶诱发的大鼠脑积水模型伴有室管膜层的脱落和破坏，由此我们推测脑室出血后凝血酶导致室管膜细胞粘附连接的破坏可能是导致脑积水的重要机制。本研究将进一步利用整体大鼠脑室出血模型、离体室管膜细胞培养，结合PAR-1、Src、PAK和VE-cadherin基因敲除转基因小鼠，明确凝血酶在脑室出血后急性脑积水产生中的作用以及对室管膜粘附连接的影响，并阐明PAR-1-Src-PAK1 信号通路是否为凝血酶导致粘附连接破坏的主要机制。本课题的顺利完成将有利于理解脑室内出血的发病机制，为探索有效的干预措施提供更为可靠的理论依据。

第一部分：侧脑室注射凝血酶导致了大鼠脑积水的发生.脑室出血后继发脑积水是导致病人临床症状恶化的重要原因，单纯减轻脑积水未能改善预后，我们前期研究显示凝血酶在脑室出血后继发脑积水中起到了非常重要的作用，但是其作用机制至今未明。单独侧脑室注射凝血酶导致了大鼠脑积水的发生，并且伴随有室管膜细胞的破坏和侧脑室周围血脑屏障的破坏。这提示我们，凝血酶可能是由于破坏了脉络丛的连接蛋白导致脑脊液的过度分泌而导致了大鼠脑积水的发生。.第二部分：脉络丛连接蛋白在凝血酶诱导脑积水中的作用及潜在通路机.脉络丛与脑脊液的产生密切相关。本研究初步探讨了脉络丛连接蛋白（VE-cadherin）在凝血酶诱发脑积水中的作用。而且我们初步发现，抑制PAR1通路可以改善凝血酶诱发的脑积水。.第三部分：乙酰唑胺在凝血酶诱导脑积水中的作用.乙酰唑胺作为碳酸酐酶抑制剂在临床被用于利尿，减少房水分泌等。乙酰唑胺可以减少脑脊液分泌，我们实验也利用核磁探索了乙酰唑胺对凝血酶诱发脑积水的治疗作用。.第四部分：米诺环素对自发高血压大鼠（SHRs）脑积水的治疗作用.初步探讨了米诺环素对脑积水的治疗机制。发现米诺环素治疗可以显著改善SHRs的脑积水状况。.第五部分：自发性脑出血患者血肿远隔部位DWI高信号病灶（Remote diffusion-weighted imaging lesion, R-DWIL）的发生机制、临床和影像学特征.发现无论脑出血发生在深部、脑叶、脑干或是小脑，R-DWIL均可以出现，较高的空腹血糖、高级别脑白质病变、肾功能不全和脑小血管病负担与自发性脑出血后R-DWIL的出现有关。