TRPM4通道在蛛网膜下腔出血后脑血管痉挛中的作用及分子机制

Cerebral vasospasm is the most specific complications and the important risk factor for poor prognosis of SAH, which has the following characteristics: (1) the occurrence of relatively fixed time window for easy selection of targeted prevention and intervention timing; (2) the development is mostly progressive, theoretically it has enough opportunities for intervention; (3) CVS was mainy due to cerebral vascular functional changes caused by abnormal rather than organic, theoretically it could be reversible and has high expectations of cure; (4) CVShas something with the primary disease and determine its outcome has major therapeutic implications. CVS is the main target for the research and treatment of SAH. After SAH, the effects of TRPM4 for CVSMCs myogenic tone and mechanisms of autoregulation of cerebral blood flow abnormalities were related to CVS. This paper aims to research TRPM4 molecules that play an important role in the cerebrovascular physiological functions and are relatively new as core , trying to clarify its role and molecular mechanisms in CVS in order to provide the scientific basis and a unique perspective for the mechanism of emerging research and the prognosis of CVS in SAH.

脑血管痉挛(cerebral vasospasm,CVS)是SAH最具特异性的并发症和预后不良的最主要危险因素,其具有以下特点:(1)发生时间窗较为固定,便于具有针对性的选择预防和干预时机;(2)发展多为渐进性,理论上具有足够的干预机会;(3)主要是由于脑血管的功能性异常而非器质性改变引起,理论上具有较高可逆性和治愈期望;(4)与原发病预后关系密切并决定其转归,具有重大的治疗意义。CVS是SAH研究和治疗的最主要靶点。SAH后TRPM4对CVSMCs肌源性紧张度和脑血流自身调节的异常作用与CVS的发生机制有关。本课题计划以在脑血管生理功能中扮演重要角色且较新颖的TRPM4分子作为研究核心,力图阐明其在CVS中的作用和分子机制,为CVS的机制研究和SAH的预后改善提供新兴的科学依据和独特视角。

脑血管痉挛(cerebral vasospasm,CVS)是SAH最具特异性的并发症和预后不良的最主要危险因素,CVS是SAH研究和治疗的最主要靶点。SAH后TRPM4对CVSMCs肌源性紧张度和脑血流自身调节的异常作用与CVS的发生机制有关。本研究将120只清洁级SD大鼠随机分为体外实验组（48只）及体内实验组（72只），体外实验组分为sham组（24只）及SAH组（24只），各实验组下设3、5、7天三个时间点亚组，体内实验组又分为sham组（18只），SAH组（18只），sham + 9-Phe组（18只）及SAH + 9-Phe组（18只），同样，各实验组下设3、5、7天三个时间点亚组。采用立体定向仪向大鼠鞍上池注入鼠尾自体动脉血建立SAH模型。通过置入式微量泵分别向sham组和SAH组大鼠侧脑室持续泵入生理盐水，向sham+9-Phe和SAH+9-Phe组大鼠侧脑室持续TRPM4通道特异性阻滞剂9-Phenanthrol（9-Phe），SAH模型建立后3、5、7天，分离体外实验组大鼠脑动脉平滑肌细胞，通过免疫印迹法检测TRPM4通道在脑动脉平滑肌细胞中的表达和转位。通过全细胞膜片钳技术测定脑动脉平滑肌细胞中TRPM4通道的电流，通过加压肌动扫描检测脑动脉肌源性紧张度。通过激光多普勒和荧光微球法分别测量体内实验组大鼠皮层和全脑血流量。结果显示：sham组和SAH组大鼠脑动脉平滑肌细胞中都观察到了TRPM4通道的表达。SAH组大鼠TRPM4通道蛋白的表达丰度明显高于sham组；SAH组大鼠TRPM4通道细胞膜的转位率明显高于sham组；钳制电压为 -80 mV到 +50 mV时，SAH组大鼠脑动脉平滑肌细胞所测TRPM4通道电流强度均大于sham组；使用9-Phe后，所测通道电流明显减小。SAH组大鼠脑动脉肌源性紧张度明显高于sham组，加入9-Phe后，SAH组及sham组大鼠脑动脉肌源性紧张度明显下降；其中，SAH组大鼠脑动脉肌源性紧张度的下降明显高于sham组；SAH组大鼠局部皮层及全脑血流量较sham组下降，在使用9-Phe后，各组大鼠脑皮层及全脑血流量回升明显。本研究提出重要结论：SAH对TRPM4通道活性具有诱导作用， 而TRPM4通道活性的增加在SAH后CVS中起到关键作用。