构建大脑中动脉阻塞脑缺血模型大鼠的类型分析

背景：线栓法造成短暂性大脑中动脉阻塞是研究大鼠局灶性脑缺血普遍使用的模型制作方法。但制作大鼠脑缺血模型的类型存在一定差异,可能导致实验结果的偏差。目的：分析大脑中动脉阻塞线栓法制作大鼠脑缺血模型的类型及其影响因素。方法：雄性SD大鼠166只,参照Longa线栓法造模,术后24h行MRI扫描,根据扫描结果将大鼠分成皮质梗死组、皮质下梗死组及无梗死组,分析造模时线栓插入的深度。结果与结论：皮质梗死组、皮质下梗死组和无梗死组大鼠的线栓插入深度分别为（19.9±0.9）,（19.0±1.1）和（17.7±1.3）mm,皮质梗死组大鼠的线栓插入最深,而无梗死组的线栓插入最浅（P〈0.01）。提示插入深度不同导致的大鼠脑梗死的类型也不同,线栓插入越深,皮质梗死的概率可能越大。     

大鼠大脑中动脉阻塞后DNA单链断裂损伤的实验研究

目的 观察大鼠永久性大脑中动脉阻塞(pMCAO)后，相应区域DNA断裂损伤情况，探讨DNA单链损伤在pMCA0所致脑组织损伤中的意义。方法 采用常规HE组织染色明确大鼠pMCAO模型成功与否及其损伤范围，采用DNA聚合菌—l K1enov片段原位杂交方法检测pMCAO不同时间点DNA单链断裂损伤情况。结果 损伤区域单链DNA断裂的K1enov阳性细胞在pMCA0后6h即有表达(P＜0．01），在24h时达到高16(P＜0．01)，72h时有所下降(P＜0．01)。结论 单链DNA断裂损伤在pMCA0后6h即可出现，并逐渐积累，成为缺血半暗带内细胞损伤发展过程的重要环节，并可能预示半暗带损伤范围的不断扩大。     

线栓法制备大鼠大脑中动脉脑缺血模型的改进 与经验探讨

线栓法制备大鼠大脑中动脉阻塞再灌注模型被普遍认为是标准局灶性脑缺血动物模型,但该方法存在操作要求高,模型差异大,影响因素多等问题。笔者结合实际操作经验和既往文献报道,从动物选择、术前准备、线栓制备和插线深度、模型制备、术后再灌、术后护理与并发症、模型评价等方面进行探讨,以期进一步提高线栓法制备大鼠大脑中动脉阻塞再灌注模型成功率。     

鼠须替代尼龙线栓塞大鼠大脑中动脉造成局灶性脑缺血模型研究

背景：尼龙线缺乏一定硬度致使进线深度不够常导致局灶性脑缺血模型失败，寻找一种内在性质均一，具有一定硬度和弹性的栓线是提高线栓法大鼠大脑中动脉局灶性脑缺血模型成功率的关键。目的：寻找提高大鼠大脑中动脉局灶性脑缺血模型成功率的方法。设计：随机对照实验。地点和材料：实验地点为济南军区总医院全军神经内科中心动物实验室。动物：雄性Wistar大鼠60只，体质量160～270g，由山东医科大学实验动物中心提供，实验前自由进食，单纯随机分为鼠须栓塞及尼龙线栓塞两组。干预措施：比较用聚乙烯醇处理的鼠须和尼龙栓线对模型成功率及梗死体积的影响。主要观察指标：模型出现率；梗死体积。结果：鼠须和尼龙线栓塞两组动物的模型出现率分别为96％和55％，缺血12h点梗死体积两组相差不显著[(209.6&;#177;21．4)比(227，6&;#177;40．9)mm^3]。结论：鼠须内在性质均一并具有良好的硬度和弹性，聚乙烯醇良好的膨胀性可弥补鼠须直径的不均一性，鼠须聚乙烯醇栓线可显著提高模型成功率。     

大鼠大脑中动脉局灶性脑缺血局部脑血流动态观察

目的：动态观察了鼠须栓塞大鼠大脑中动脉局灶性脑缺血模型局部脑血流（regional cerebral blood flow,rCBF）变化与时间的关系。方法：雄性Wistar大鼠12只，体重250－350g。根据缺血时间分为缺血0．5，1．0，1．5，2．0，3．0，6．0，9．0，12．0h。采用鼠须栓塞法制做大鼠大脑中动脉局灶性脑缺血模型，氢清除法测定大鼠大脑中动脉供血中心缺血各时点大脑皮层rCBF变化，结果：12h组2只动物因吸入氢气过量致窒息死亡，其他全部动物均在规定时间内完成rCBF测定。缺血前rCBF为（149．77&;#177;6．76）ml/(100g.min），缺血30min下降至（106．94&;#177;7．21）ml/(100g.min)，缺血6h降至（12．73&;#177;1．66）ml/(100g.min）。除缺血90min和2h点rCBF无统计学显著差异外，其它各时间点rCBF均存在显著差异（P＜0．01）。rCBF随时间渐趋下降，回归分析示与时间呈显著相关（r=-0.77,P=0.024)，至缺血12h rCBF不能测出。结论：该研究为扩大治疗时间窗的保护性治疗提供了脑血流变化的理论依据。     

大鼠大脑中动脉脑缺血模型的影响因素

影响大鼠大脑中动脉闭塞脑缺血动物模型建立的因素有:大鼠品种、麻醉剂、手术部位和线栓等,其中线栓的选择是模型制作成功的关键,包括线栓的种类、长度、直径、硬度、放置方法,以及线栓端部的处理等.线栓制备等因素的改进大大提高了脑缺血动物模型的成功率.     

大鼠大脑中动脉梗死和脑水肿的变化

目的 探讨大鼠永久性大脑中动脉闭塞致脑梗死和脑水肿的变化特点.方法 Sprague-Dawley雄性大鼠随机(随机数字法)分成正常组、假手术组和脑缺血组,其中脑缺血组按缺血时间分成2 h,4 h,6 h,12 h,18 h,24 h和30 h 7个亚组.线栓法制作大鼠永久性右侧大脑中动脉闭塞脑缺血模型,行2%氯化三苯基四氮唑溶液染色测量脑梗死比及干湿称重法测量脑含水量,动态观察两者的变化特点.结果 在脑缺血组,缺血4 h局部出现脑梗死灶,方差分析结果显示缺血4 h,6 h脑梗死比无差别(P=0.091);与缺血6 h相比,缺血12 h,18 h,24 h和30 h脑梗死比显著增高(P<0.01),24h达高峰.缺血4 h脑含水量开始增加,6 h后加重,24 h达高峰;缺血18 h,24 h,30 h非缺血侧脑含水量亦增高.脑水肿和脑梗死比存在显著正相关(r=0.834,P<0.01).结论 大脑中动脉闭塞6 h是脑梗死和脑水肿加重的转折点,24 h脑梗死和脑水肿达到高峰,可为临床评估脑梗死和脑水肿的病情及治疗干预的时间窗选择提供实验参考.     

改良的大鼠脑局部缺血模型

目的介绍一种快速、稳定的大鼠脑局部缺血模型。方法32只Wistar雄性大鼠，按照Longa的线栓法制作局部脑缺血模型，但在放入栓塞线时不结扎翼腭动脉(PPA)，通过局部脑血流监测、动物行为学评分、脑含水量测定、红四氮唑(TTC)染色和病理学检查等方法评价该模型的可靠性。结果动物麻醉后一般只需15min左右即可完成栓线手术，术后大鼠大脑中动脉区域血流量下降，神经功能损伤明显，脑含水量增高，TTC染色脑梗死区苍白，病理学检查显示缺血灶星形胶质细胞肿胀，神经元固缩坏死。结论不结扎PPA的大鼠脑局部缺血模型，缺血效果明确可靠，手术时间短，是理想的研究脑缺血的实验模型。     

栓线法建立大脑中动脉局灶缺血实验模型对再灌注损伤的评价意义

目的为临床脑缺血研究提供更合理实用的基础研究模型。方法选用健康Wistar大鼠41只,雌雄不限,体质量250～280g,用栓线法制作大鼠大脑中动脉局灶脑缺血模型,并限定不同时间点再灌注。结果正常对照组,假手术组,缺血30min再灌注24h组未发现神经功能缺损,评分为0分。缺血90min-再灌注模型神经功能缺损评分为2.2±0.4,梗死灶部位累及皮层和基底核。缺血持续24h组评分为3.4±0.5,与缺血90min再灌注组比,t=3.797,P<0.01。结论栓线法大鼠大脑中动脉局灶脑缺血缺血90min再灌注模型更接近临床脑缺血的病程。     

Endothelial dysfunction in rat mesenteric resistance artery after transient middle cerebral artery occlusion

Stroke triggers a local and systemic inflammatory response leading to the production of cytokines that can influence blood vessel reactivity. In this study, we aimed to assess whether cerebral ischemia/reperfusion could affect vasoconstriction and vasodilatation on mesenteric resistance arteries (MRA) from Wistar Kyoto rats. The right middle cerebral artery was occluded (90 min) and reperfused (24 h). Sham-operated animals were used as controls. Plasma levels of interleukin (IL)-6 and IL-1beta were measured at 24 h. Vasoconstrictor and vasodilator responses were recorded in a wire myograph. Protein expression was determined by Western blot and immunofluorescence, and superoxide anion (O(2)(.)) production was evaluated by ethidium fluorescence. In MRA, ischemia/reperfusion increased plasma levels of IL-6, O2. production, protein expression of cyclooxygenase-2, and protein tyrosine nitrosylation, but it impaired acetylcholine (ACh) vasodilatation without modifying the vasodilatations to sodium nitroprusside or the contractions to phenylephrine and KCl. Superoxide dismutase (SOD) and indomethacin reversed the impairment of ACh relaxation induced by ischemia/reperfusion. However, N(omega)-nitro-l-arginine methyl ester affected similarly ACh-induced vasodilatations in MRA of ischemic and sham-operated rats. Protein expression of endothelial and inducible nitric-oxide synthase, copper/zinc SOD, manganese SOD, and extracellular SOD was similar in both groups of rats. Our results show MRA endothelial dysfunction 24 h after brain ischemia/reperfusion. Excessive production of O2. in MRA mediates endothelial dysfunction, and the increase in plasma cytokine levels after brain ischemia/reperfusion might be involved in this effect.     

鼠须替代尼龙线栓塞大鼠大脑中动脉造成局灶性脑缺血模型研究

背景尼龙线缺乏一定硬度致使进线深度不够常导致局灶性脑缺血模型失败,寻找一种内在性质均一,具有一定硬度和弹性的栓线是提高线栓法大鼠大脑中动脉局灶性脑缺血模型成功率的关键.目的寻找提高大鼠大脑中动脉局灶性脑缺血模型成功率的方法.设计随机对照实验.地点和材料实验地点为济南军区总医院全军神经内科中心动物实验室.动物雄性Wistar大鼠60只,体质量160～270 g,由山东医科大学实验动物中心提供,实验前自由进食,单纯随机分为鼠须栓塞及尼龙线栓塞两组.干预措施比较用聚乙烯醇处理的鼠须和尼龙栓线对模型成功率及梗死体积的影响.主要观察指标模型出现率;梗死体积.结暴鼠须和尼龙线栓塞两组动物的模型出现率分别为96%和55%,缺血12 h点梗死体积两组相差不显著[(209.6±21.4)比(227.6±40.9)mm3].结论鼠须内在性质均一并具有良好的硬度和弹性,聚乙烯醇良好的膨胀性可弥补鼠须直径的不均一性,鼠须聚乙烯醇栓线可显著提高模型成功率.     

脑动脉粥样硬化模型大鼠大脑中动脉的蠕变

背景:蠕变是生物材料黏弹性固体的表现形式之一,脑动脉硬化和脑出血的防治有必要了解脑动脉硬化大脑中动脉的蠕变力学特性.目的:比较正常和动脉粥样硬化动物模型大脑中动脉的蠕变力学特性,确定动脉粥样硬化对大脑中动脉蠕变特性的影响.方法:SD雄性大鼠随机分为两组,模型组肌注维生素D3+尼古丁灌胃+高脂饮食制备动脉粥样硬化模型,对照组正常饮食,4周后处死大鼠取大脑中动脉为标本试件.在日木岛津电子万能试验机上对正常和动脉粥样硬化动脉标本试样进行蠕变实验.蠕变实验的应力增加速度为0 01 MPa/s.设定实验时间为7 200 s,采集100个数,以一元线性回归分析的方法处理实验数据,记录蠕变曲线和数据,以及应变与时间的变化规律.结果与结论:正常和动脉粥样硬化大鼠大脑中动脉蠕变最初600 s变化较快,之后应变缓慢下降,正常动脉标本7 200 s蠕变量高于动脉粥样硬化动脉标本(50.38%,48.26%,P＜0.05).说明正常和动脉粥样硬化大鼠大脑中动脉具有不同的蠕变力学特性,提示蠕变曲线是以指数关系变化的,动脉粥样硬化对大脑中动脉蠕变特性具有一定影响.     

Release of spermidine from the rat cortex following permanent middle cerebral artery occlusion

Summary— We have studied the effects of middle cerebral artery (MCA) occlusion in rats on polyamine efflux in the parietal cortex using the microdialysis technique. Dialysis probe implantation itself provoked a delayed, prolonged and vigorous release of spermidine and putrescine. Spermidine release returned to stable baseline levels within 48 hours. Putrescine release also returned to lower levels within this time period but putrescine levels in the dialysate fluctuated dramatically in individual animals. Because of the underlying effects of the dialysis probe (likely a reflection of traumatic cerebral damage and stimulation of polyamine metabolism and release within the immediate vicinity of the dialysis probe), MCA occlusion was performed 48 hours after probe implantation. MCA occlusion persistently (5/5 animals) resulted in a significant increase in cortical spermidine efflux, although the onset, magnitude and duration of this increased release was variable. Putrescine efflux was significantly increased in 2/5 animals with MCA occlusion but the increase in release was similar to the spontaneous fluctuations observed in control animals. Spermine was not detectable in cortical dialysates of control or MCA occluded groups. Spermidine, but not spermine or putrescine is consistently released from the parietal cortex following permanent focal ischaemia and may contribute to ischaemic neuropathology either through its effects at the N-methyl-D-aspartate (NMDA) receptor or via direct, and as yet uncharacterised, neurotoxic effects.     

大鼠自体血栓结合线栓阻塞大脑中动脉制备脑缺血模型的建立与评价

目的建立和评价大鼠自体血栓结合线栓阻塞大脑中动脉（MCA）制备的脑缺血动物模型。方法大鼠随机分为假手术组（10只）、线栓组（12只）、血栓结合线栓组（12只）。线栓组大鼠用尼龙栓线阻塞MCA制备大脑中动脉闭塞（MCAO）模型。血栓结合线栓组由颈外动脉插入改良的内置尼龙套线聚乙烯导管，插管成功后栓线退出一定长度，血液在导管内自凝后拔出套线，经导管推入凝血酶，血栓形成后再次插入套线，根据套线标记的长度向前推进血栓，使之阻塞大鼠MCA制备MCAO模型。术后6h，观察大鼠神经症状评分；测定脑组织含水量、脑梗死面积，观察大鼠脑组织病理变化。结果线栓组和血栓结合线栓组均较假手术组大鼠的神经症状评分增高，脑组织含水量增加，脑梗死面积增大（P均〈0．01），脑组织出现明显的病理损伤；与线栓组比较，血栓结合线栓组大鼠的神经症状评分、脑组织含水量、脑梗死面积及脑组织病理损伤差异均无显著性（P均〉0．05）。结论自体血栓结合线栓阻塞大鼠MCA可引起神经功能损害、脑组织水肿，造成脑组织明显的病理损伤，该法制备的MCAO模型可使血栓阻塞在期望血管（MCA）并可进行脑缺血／再灌注研究，防止血栓模型制备过程中及区域动脉溶栓治疗后再出血等，具有阻塞位置确切、梗死范围恒定、模型易于操作及可重复性好等特点。     

Protective effect of exogenous administration of alpha-tocopherol in middle cerebral artery occlusion model of cerebral ischemia in rats

Oxidative stress due to increased free radical generation and depletion of endogenous antioxidants have been implicated in ischemia-reperfusion-induced neuronal injury. The present study was carried out to study the effect of acute administration of alpha-tocopherol in the middle cerebral artery (MCA) occlusion model of stroke in rats. Rats were anesthetized using chloral hydrate (400 mg/kg i.p.) and subjected to 2 h of transient MCA occlusion. alpha-Tocopherol was administered at the dose of 125 and 250 mg/kg orally 1 h prior to the occlusion of MCA. Motor performance test (grip test, foot fault test, rotarod performance test, spontaneous locomotor activity), markers of oxidative stress and 2,3,5-triphenyl tetrazolium chloride staining were carried out 24 h after MCA occlusion. A vehicle-treated group was run parallel. It was observed that alpha-tocopherol at the dose of 125 mg/kg neither improved neurologic deficit, nor decreased the raised level of oxidative stress markers in comparison with the MCA-occluded rats. However, higher dose of alpha-tocopherol (250 mg/kg p.o.) afforded significant protection as evident by increase in motor performance tests and a decrease in the volume of infarction. The raised levels of malondialdehyde after MCA occlusion were also significantly attenuated. The results demonstrate that exogenous administration of alpha-tocopherol is able to reduce the neuronal damage caused during ischemia-reperfusion, which can be attributed to its antioxidant activity.     

大脑中动脉闭塞后存活患者预后不良的相关因素分析

目的对大脑中动脉闭塞(MCAO)后存活患者进行长期随访,观察预后不良的影响因素,并进行分析。方法选取2006年1月至2013年12月住院就诊,行头颈部CT血管成像(CTA)或磁共振血管成像(MRA)证实存在MCAO的119例患者进行随访,以改良Rankin评分(mRS)为结局指标,将相关因素进行统计学分析。结果 119例MCAO患者中失访17例(14.28%),平均随访46.8个月。将MCAO患者分为功能预后不良组(mRS2,48例)和功能预后良好组(mRS≤2,54例),并进行两组比较;功能预后不良组年龄、美国国立卫生研究院卒中量表(NIHSS)评分、超敏C反应蛋白(h-CRP)、纤维蛋白原(FBg)、D二聚体(D-Dimer)水平均显著高于功能预后良好组,甘油三酯(TG)水平显著低于结局良好组,差异具有统计学意义。Logistic回归分析显示年龄及NIHSS评分为结局不良的独立危险因素。结论年龄越大、NIHSS评分越高,MCAO后存活患者临床预后越差。