laminin/Integrin相互作用调节蛛网膜下腔出血后脑血管重塑的作用及机制研究

Vascular autoregulation and pathological vascular remodeling are vital part in the pathological process of subarachnoid hemorrhage. The phenotype transformation of vascular smooth muscle cells (VSMC) is considered to be one of the key factors witch leading to the imbalance of cerebral vascular autoregulation and the pathological remodeling of cerebral vessels. It is found that the interaction of LN and integrin plays an important role in maintaining the integrity of the vascular wall and the physiological state of VSMC. Our previous study also found that VSMC transformed into synthetic phenotypes after subarachnoid hemorrhage, and the damage of vascular endothelial cells was promoted by inflammatory reaction through decreased of LN. But does the LN/Integrin interaction could lead to the inhibition of VSMC phenotypic transformation after subarachnoid hemorrhage, and what is the underlying mechanism? Therefore, this study proposed by in vitro hemoglobin stimulated VSMC model and SD rat SAH model, using recombinant human LN, alpha 7 beta 1 integrin monoclonal antibody, small interfering RNA and adenovirus transfection and other interventions, and by means of western blot, immunofluorescence technique, basilar artery diameter and wall morphology detection, behavior evaluation, to determinate the effect of regulation of LN/Integrin interaction on SAH induced phenotypic transformation of VSMC and cerebral blood flow auto-regulation function, and preliminarily explore its potential mechanism.

蛛网膜下腔出血（SAH）后血管平滑肌细胞（VSMC）表型转化是导致脑血管病理性重塑和脑血管自动调节功能失衡的关键因素之一。研究发现LN/Integrin相互作用对维持血管壁完整性以及VSMC生理状态具有重要作用。我们前期研究也发现，SAH后VSMC向合成分泌表型转变，且LN表达明显下降，并通过炎症反应促进血管内皮细胞损害。但LN/Integrin相互作用是否可以抑制SAH后VSMC表型转变，其机制又如何？因此本课题拟通过体外血红蛋白刺激VSMC模型和载体大鼠SAH模型，利用重组人LN，α7β1Integrin单克隆抗体，小干扰 RNA以及腺病毒转染等干预手段，通过western blot、免疫荧光技术、血管形态学检测、行为学评估，以及测定脑血流量等多元化手段，最终了解调控LN/Integrin相互作用对SAH引起的VSMC的表型转变以及脑血流自动调节功能的影响，并初步探讨其潜在机制。

研究背景：蛛网膜下腔出血（subarachnoid hemorrhage，SAH）是神经外科常见的急性临床危重症，因其发病率和致死致残颇高，即使经积极有效地治疗，也可能会遗留不同程度的神经功能缺失。研究认为脑血管痉挛（cerebral vasospasm，CVS）是SAH后导致高致残致死率，以及迟发性缺血性神经功能障碍（delayed ischemic neurological deficit，DIND）的首要原因。虽然已有大量文章报道了SAH后CVS发生发展的机制，但是针对其治疗仍然不甚理想。已有研究显示脑血管平滑肌细胞（vascular smooth muscle cells，VSMCs）病理性收缩参与到CVS的发生发展过程中，并且在痉挛的血管壁中检测到合成分泌型VSMCs的存在。这些研究数据说明，VSMCs表型转换有可能参与到CVS的发生发展过程中，并导致不良预后。.研究内容：通过建立SD大鼠颈内动脉穿刺蛛网膜下腔出血模型，不同时间点用WB实验检测大脑动脉环VSMCs表型转换标记蛋白含量，以及应用免疫荧光实验检测基底动脉形态变化。立体定向技术进行大鼠大脑PPARβ/δ过表达腺病毒注入，再用WB实验检测大脑动脉环VSMCs表型转换标记蛋白含量，以及应用免疫荧光实验检测基底动脉形态变化。之后对大鼠进行神经行为学评分，再之后测量大鼠脑水肿、脑容量、脑血容量等情况。.结果：SAH后VSMCs表型转换导致CVS发生，导致基底动脉管径狭窄，管壁增厚。过表达PPARβ/δ后能明显抑制VSMCs表型转换，同时改善CVS的发生发展，减轻管壁增厚以及管径狭窄的程度。并提高大鼠神经功能行为学评分。进一步研究证实ERK信号通路参与到PPARβ/δ调节VSMCs表型转换的过程中。.科学意义：以往研究将重点放在CVS跟炎症反应、细胞凋亡、内皮细胞损伤、血脑屏障破环等的关系上，忽略了VSMCs的作用。本研究阐述了PPARβ/δ抑制VSMCs表型转换进而改善SAH后CVS，为临床治疗CVS提供了新的思路。