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背景:近年来研究发现一氧化氮参与了脑缺血损伤的发生,但对于其确切作用至今尚无统一的结论。目的:探讨一氧化氮在缺血再灌注脑损伤中的作用,比较两类钙通道阻滞剂的脑保护作用。设计:完全随机设计,对照实验研究。地点和材料:实验在首都医科大学附属北京儿童医院ICU实验室完成,实验动物为由首都医科大学动物实验室提供体质量2.0～2.4kg新西兰兔66只。方法:夹闭双侧颈总动脉和颈动脉30min后放开制作兔脑缺血再灌注模型。选取36只新西兰兔分为假手术、再灌注0.5、1.5、3、6、24h共6组,测定脑皮层匀浆一氧化氮及含水量。另选30只新西兰兔分假手术、安慰剂(0.9%生理盐水)、尼莫地平(首剂5μg/kg,20min内静脉注入,维持量0.5μg/kg·min)、氯胺酮(首剂20mg/kg,30min内静脉注入,维持量10mg/(kg·h)、尼莫地平+氯胺酮治疗共5组,于再灌注30min开始持续静脉用药至再灌注6h取脑皮层,使用Griess法测定一氧化氮,以Fluo-3Ca2+荧光试剂标记新鲜活脑片细胞内游离钙(犤Ca2+犦i),激光共聚焦显微镜测定犤Ca2+犦i相对荧光强度。主要观测指标:生理参数变化,再灌注不同时间兔脑皮层一氧化氮及含水量变化,用药组兔脑皮层一氧化氮、含水量、犤Ca2+犦i。结果:再灌注后脑皮层一氧化氮、含水量逐渐升高,于再灌注6h达较高水平犤分别?
Background: In recent years, studies have found that nitric oxide participates in the occurrence of cerebral ischemic injury, but there is no consistent conclusion about its exact role so far. AIM: To investigate the role of nitric oxide in brain injury induced by ischemia-reperfusion and to compare the protective effect of two types of calcium channel blockers on brain injury. Design: Completely randomized design, controlled experimental study. Location and Materials: The experiment was performed at ICU Laboratory of Beijing Children’s Hospital affiliated to Capital Medical University. The experimental animals were 66 New Zealand rabbits with body weight 2.0-2.4kg provided by Animal Laboratory of Capital Medical University. Methods: The bilateral common carotid arteries and carotid arteries were occluded for 30 minutes and then released to make a rabbit model of cerebral ischemia-reperfusion. Thirty-six New Zealand rabbits were randomly divided into 6 groups: 0.5, 1.5, 3, 6 and 24 hours after reperfusion. Nitric oxide and water content were measured in the cortex homogenate. 30 New Zealand rabbits were divided into sham operation, placebo (0.9% saline), nimodipine (the first dose of 5μg / kg, intravenous injection within 20min, the maintenance dose of 0.5μg / kg · min), ketamine (first dose of 20mg / kg intravenously 30min, the maintenance dose 10mg / (kg · h), nimodipine + ketamine treatment a total of 5 groups, 30min after reperfusion began continuous intravenous drug administration to reperfusion 6h cortex, using Griess method for the determination of nitric oxide Fluorescence reagent Fluo-3Ca2 was used to label intracellular free calcium (Ca2 + 犦 i) in fresh brain slices, and the relative fluorescence intensity of Ca2 + 犦 i was measured by laser scanning confocal microscope.MAIN OUTCOME MEASURES: Changes in physiological parameters, reperfusion of rabbits at different times The changes of nitric oxide and water content in the cerebral cortex, the nitric oxide and water content in the cerebral cortex of the treated group were significantly higher than those in the control group.Results: After reperfusion, nitric oxide and water content in the cerebral cortex gradually increased and reached a high level at 6h after reperfusion Level 犤 respectively?