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背景:某些颅脑手术中难免会对脑血管进行牵拉、夹闭等机械性刺激,导致急性机械性脑血管痉挛的发生,目前这种急性机械性脑血管痉挛的病理生理及病理预后尚不清楚。目的:观察猫大脑中动脉血管直径、脑血流量、血管壁和血管内皮细胞超微结构在机械性刺激痉挛后早期(2h)的变化。设计:开放性实验。单位:首都医科大学附属北京天坛医院神经内科和北京市神经外科研究所。材料:选用健康成年的杂种猫6只,雌雄不拘,体质量2.5～3.5kg,由中国医学科学实验动物研究所提供。Periflux5010型激光多普勒血流仪(瑞典Perimed公司)。方法:实验于2005-08/2006-03在北京市神经外科研究所完成。200g/L水合氯醛腹腔注射(2mL/kg)麻醉后,取俯卧位。正中切开头皮,于前囟后1.5cm,旁开1.5cm开方形骨窗,8×10mm,挑破硬脑膜,选择无血管或少血管的脑表面固定激光多普勒血流计的微细探头。再使动物侧卧位,利用手术显微镜,通过眶下入路,暴露右侧大脑中动脉。选择大脑中动脉跨越嗅束前部位,利用钝性器械重复刺激大脑中动脉,频率为100次/min,持续30min。分别于刺激前,刺激结束后0,0.5,1.0,1.5,2.0h测量刺激前后大脑中动脉直径的变化,监测皮层脑组织灌流指数的变化,观察刺激后2h大脑中动脉血管壁和内皮细胞超微结构的变化。主要观察指标:刺激前,刺激结束后0,0.5,1.0,1.5,2.0h大脑中动脉直径和皮层脑组织灌流指数的变化以及刺激2h后大脑中动脉血管壁和内皮细胞超微结构的变化。结果:纳入6只实验动物全部进入结果分析。①大脑中动脉直径的变化:刺激结束后0,0.5,1.0h大脑中动脉直径分别为(0.617±0.129),(0.723±0.082),(0.840±0.084)mm,与刺激前比较,明显变窄[(0.897±0.066)mm,t=4.74,4.017,1.299,P<0.01]。②脑组织灌流指数的变化:刺激结束后0,0.5,1.0,1.5,2.0h灌流指数分别为67.8±18.5,82.5±17.5,89.8±24.0,94.0±22.2,98.5±21.0,明显低于刺激前(159.2±23.5,t=4.716～7.469,P<0.01)。③大脑中动脉超微结构的变化:大脑中动脉经急性机械性刺激后早期(2h)内皮细胞染色质边集,凝聚成新月形小体,线粒体嵴模糊不清。结论:机械性刺激猫大脑中动脉可导致脑血管痉挛。刺激后早期(2h)即出现内皮细胞超微结构的变化,显示内皮细胞的凋亡现象。提示颅脑手术中对脑血管的机械性刺激应尽可能的轻微,尽量减少对脑血管的机械性刺激,避免急性脑血管痉挛的发生。
Background: Some craniocerebral operations will inevitably pull the cerebral blood vessels, clamping and other mechanical stimulation, leading to the occurrence of acute mechanical vasospasm, the current pathophysiology of acute mechanical cerebral vasospasm and pathological prognosis Not clear. OBJECTIVE: To observe the changes of vascular diameter, cerebral blood flow, blood vessel wall and ultrastructure of vascular endothelial cells in middle cerebral artery (MCAO) in the early (2h) after mechanical stimulus spasm in cats. Design: Open experiment. SETTING: Department of Neurology, Beijing Tiantan Hospital, Beijing Capital Medical University and Beijing Institute of Neurosurgery. MATERIALS: 6 healthy adult hybrid cats were selected, both male and female, body weight 2.5 ~ 3.5kg, provided by China Medical Science Experimental Animal Research Institute. Periflux Model 5010 Laser Doppler Flowmeter (Perimed, Sweden). Methods: The experiment was performed at Beijing Institute of Neurosurgery from August 2005 to March 2006. 200g / L chloral hydrate intraperitoneal injection (2mL / kg) anesthesia, prone position. The middle of the scalp incision, 1.5cm after the bregma, open 1.5cm open square bone window, 8 × 10mm, dural dural ablation, the choice of no blood vessels or less blood vessels on the surface of the fixed laser Doppler sphygmomanometer . Animals were then placed in the lateral position, using a surgical microscope, through the infraorbital approach, exposing the right middle cerebral artery. Select the middle cerebral artery across the olfactory tract before the site, the use of blunt instrument repeated stimulation of the middle cerebral artery, the frequency of 100 beats / min, sustained 30min. The changes of the diameter of the middle cerebral artery before and after stimulation were measured at 0, 0.5, 1.0, 1.5, 2.0 h before and after stimulation, respectively. The changes of perfusion index in cortex were monitored. The vascular wall and endothelial cells in the middle cerebral artery were observed 2 h after stimulation Microstructure changes. MAIN OUTCOME MEASURES: Changes of middle cerebral artery diameter and cortical cerebral perfusion index at 0, 0.5, 1.0, 1.5 and 2.0 h after stimulus were stimulated before stimulation and ultrastructure changes of middle cerebral artery wall and endothelial cells after stimulation for 2 h. Results: Six experimental animals were included in the result analysis. (1) The changes of the diameter of the middle cerebral artery: The diameters of the middle cerebral artery at 0, 0.5 and 1.0 hours after the stimulation were (0.617 ± 0.129), (0.723 ± 0.082) and (0.840 ± 0.084) mm, respectively, [(0.897 ± 0.066) mm, t = 4.74, 4.017, 1.299, P <0.01]. (2) The change of perfusion index of brain tissue: The perfusion index of 0, 0.5, 1.0, 1.5 and 2.0h after stimulation were 67.8 ± 18.5,82.5 ± 17.5,89.8 ± 24.0,94.0 ± 22.2,98.5 ± 21.0 respectively, which was significantly lower than that before stimulation (159.2 ± 23.5, t = 4.716 ~ 7.469, P <0.01). ③ Changes of the ultrastructure of the middle cerebral artery: The middle cerebral artery in the early (2h) after the acute mechanical stimulation of the endothelial cells chromatin edge set, condensed into crescent-shaped bodies, mitochondrial cristae blurred. Conclusion: Mechanical stimulation of middle cerebral artery in cat can lead to cerebral vasospasm. Changes in the ultrastructure of endothelial cells appeared early after stimulation (2h), showing the phenomenon of endothelial cell apoptosis. Tip brain surgery in cerebrovascular mechanical stimulation should be as mild as possible to minimize the mechanical stimulation of cerebral blood vessels, to avoid the occurrence of acute cerebral vasospasm.