神经型一氧化氮合酶参与脂多糖诱导的大鼠脑微出血的相关性研究

摘要

Objective To improve the method of cerebral microbleeds ( CMBS) model induced by lipopolysaccharide (LPS) and investigate the effect of neuronal nitric oxide synthase (nNOS) in CMBS.Methods Animals were classified into two groups:LPS treatment group (n=20) and saline control group (n=20).LPS group were treated with 1 mg/ml, 3 mg/kg,LPS or the same dose of saline by intraperitoneal injection on 0 h、12 h and 24 h.After 48 h,head MRI scan ,SWI sequence showed microbleeds .Immunofluorescence staining showed that the expression of microglia marker Iba .Western blot analysis the expression of nNOS and ZO-1 ( molecular markers of the blood brain barrier ) .Resutl s Administration of 3 mg/kg LPS group appeared point low signal in the SWI sequence .Western blot and immunofluorescence showed that ZO-1 significantly reduced while Iba and nNOS expression increased significantly .Concluis on LPS may increase the systemic inflammatory response,promote the proliferation of microglia in the brain ,increase the expression of nNOS ,and destroy the blood-brain barrier of the central nervous system ,leading to the occurrence of CMBS .%目的 改进并稳定脂多糖(LPS)诱导脑微出血(CMBS)动物模型的建立方法,为进一步研究提供稳定成熟的技术手段;探讨神经型一氧化氮合酶(nNOS)在CMBS过程中的作用.方法 40只SD大鼠,随机分成LPS给药组(n=20)和生理盐水对照组(n=20),分别于0 h、12 h和24 h腹腔注射1 mg/ml、3 mg/kg LPS或相同剂量的生理盐水,48 h后行头部MRI扫描,SWI序列显示出血灶;免疫荧光染色显示小胶质细胞标记分子Iba的表达;蛋白印迹法分析nNOS和ZO-1(血脑屏障标记分子)的表达情况.结果 3mg/kgLPS给药后,MRI显示散在SWI序列点状低信号影,蛋白印迹法及免疫荧光结果显示ZO-1明显减少,Iba及nNOS表达显著增多.结论 LPS可能通过增加全身炎症反应,促进脑内小胶质细胞增殖,增加nNOS的表达,对中枢神经系统血脑屏障产生破坏作用,从而导致微出血的产生.