摘要
目的探讨大鼠大脑中动脉栓塞模型中,内皮型一氧化氮合酶(e NOS)解偶联对神经血管单元的作用及机制。方法将80只雄性SD大鼠随机分为假手术组(n=40)和大脑中动脉栓塞(MCAO)组(n=40)。参照Longa法制作MCAO模型。栓塞后6 h,通过蛋白印记法检测缺血区e NOS不同偶联状态的表达情况及3-硝基酪氨酸(3-NT)的水平;通过尼氏染色比较缺血区神经元的形态及存活情况;通过免疫组织化学染色比较缺血区星形胶质细胞、微血管内皮细胞以及血脑屏障紧密连接对应的标记物GFAP、VWF、Occludin的表达水平;通过MRI的T2加权序列和动脉自旋标记(ASL)反应栓塞后脑组织病灶范围及血流情况。结果 MCAO后栓塞部位在T2序列上呈高信号,在ASL序列上血流信号减低。e NOS二聚体/单体的比例明显低于假手术组(P<0.05);3-NT的含量明显高于假手术组(P<0.05)。尼氏染色显示MCAO后神经元大量空泡形成,核固缩变性,数量显著减少;免疫组化结果显示,VWF、Occludin的表达较假手术组明显减少,而GFAP则明显增多(P<0.05)。结论 MCAO会导致e NOS解偶联。e NOS解偶联后NO合成受限,而具有毒性作用的3-NT产生增多,炎症反应加重,从而对神经血管单元结构及功能产生破坏作用。
Objective To investigate the effect and mechanism of e NOS uncoupling on neurovascular unit in the rats model of middle cerebral artery occlusion. Method Eighty male SD rats were randomly distributed into two groups： sham operation and middle cerebral artery occlusion（ MCAO）. MCAO was made by Longa＇s method. At 6 h after MCAO,the expression of uncoupling endothelial nitric oxide synthetase（ e NOS） and 3-nitrotyrosine（ 3-NT） in the ischemic area were analysis by Western blotting. The survival of neurons in ischemic region was compared by Nissl staining. The expression of GFAP,VWF and occludin were represented astrocytes,endothelial cells and tight junction of blood brain barrier（ BBB） were analyzed by immunohistochemistry. The range and blood flow of brain tissue were detected by MRI T2 sequence and ASL sequence. Results After MCAO,the ischemic area showed low signal on T2 sequence and the blood high signal decreased on ASL sequence. The ratio of e NOS dimer/monomer significantly decreased in MCAO group than in sham group and the expression of 3-NT significant increased in MCAO group. Immunohistochemistry showed that VWF and Occludin were decreased but GFAP increased. Conclusions MCAO may lead to uncoupling of e NOS dimers in the ischemic area. e NOS uncoupling restricted NO synthesis but increased the toxic effect of 3-NT,the inflammatory response is aggravated which can damage the structure and function of neurovascular unit.
出处
《中风与神经疾病杂志》
北大核心
2017年第6期500-503,共4页
Journal of Apoplexy and Nervous Diseases
