尼美舒利对大鼠慢性脑缺血损害的保护作用

目的探讨诱导型环氧和酶(COX-2)抑制剂尼美舒利对慢性脑缺血损害的保护作用。方法大鼠随机分为对照组、缺血组和治疗组，治疗组于术后24h开始以尼美舒利(6mg／kg）每日灌胃，连续60d，各组于60d后做病理染色、GFAP免疫组化染色及脑组织内MDA和SOD含量的测定。结果与对照组相比，缺血组GFAP阳性细胞明显增多；脑内的SOD含量下降，MDA含量增多。治疗组以上变化明显减轻，且有显著性差异。结论COX-2抑制剂尼美舒利对慢性脑缺血损伤有脑保护作用。     

人参总皂甙对大鼠脑缺血再灌注后MDA、SOD及细胞凋亡的影响

目的:观察人参总皂甙对大鼠脑缺血再灌注的保护作用,探讨其作用机制。方法:将40只大鼠随机分为4 组:假手术组、缺血再灌注组、治疗组1、治疗组2,采用线栓法制备大鼠脑缺血再灌注模型,72h断头取脑,Nissel染色光镜下观察海马CA1区病理形态变化,TUNEL法检测细胞凋亡,同时检测脑组织中丙二醛(MDA)、超氧化物歧化酶(SOD)的含量。结果:与缺血再灌注组相比,人参总皂甙治疗组光镜下病理损伤轻,脑组织中MDA含量降低、SOD含量升高,细胞凋亡数降低。结论:人参总皂甙对大鼠脑缺血再灌注损伤具有保护作用,其机制可能与抑制自由基损伤有关。     

丁苯酞氯化钠注射液对大鼠延髓缺血后微血管密度丙二醛、超氧化物歧化酶的影响

目的探讨丁苯酞氯化钠注射液对大鼠延髓缺血中的影响。方法将Wistar大鼠分为假手术组、丁苯酞氯化钠注射液治疗组(治疗组)、延髓缺血对照组(对照组),采用多点阻断脑动脉方法制造延髓缺血模型。治疗组腹腔注射丁苯酞氯化钠注射液、延髓缺血对照组腹腔注射生理盐水。分别在实验7 d、14 d时取延髓,检测脑组织的SOD、MDA水平及微血管密度。结果治疗组及缺血对照组的微血管灰度值较假手术组均增加,治疗组数值增加的幅度低于缺血对照组(P<0.01)。缺血对照组脑组织SOD水平下降,脑组织MDA浓度含量较高;与缺血对照组相比,治疗组SOD下降的幅度小(P<0.01),MDA浓度降低。结论丁苯酞氯化钠注射液能有效地清除自由基、保护微血管,对延髓缺血具有明显的保护作用。     

选择性COX2抑制剂对脑缺血再灌注损伤的影响

目的 :观察脑缺血再灌注损伤中COX2的表达以及选择性COX2抑制剂SC5 812 5对脑缺血再灌注后脑梗死体积、PGE2 含量的影响。方法 :应用小鼠短暂性局灶性脑缺血模型 ;脑梗死体积的测定采用TTC染色法 ;ELISA测定PGE2 含量 ;DNA单链损伤的测定采用PANT染色。结果 :缺血前 3 0min和缺血后 2h用药组脑梗死体积显著缩小 ,缺血后 6h延迟用药组脑梗死体积无明显变化。脑缺血再灌注后PGE2 含量显著升高。SC5 812 5的治疗显著降低了PGE2 的水平。SC5 812 5并可显著抑制缺血后DNA单链损伤的程度。结论 :提示COX2参与了脑缺血再灌注损伤 ,选择性COX2抑制剂在小鼠局灶性脑缺血再灌注损伤的模型中起着重要作用     

乌司他丁对小鼠脑缺血-再灌注损伤的保护作用及对Nrf2/HO-1通路影响的研究

目的观察乌司他丁对小鼠脑缺血-再灌注后脑损伤的保护作用及对Nrf2/HO-1通路的影响。方法健康成年雄性CD1小鼠120只,随机分成4组(n=30):假手术组、脑缺血-再灌注组、乌司他丁小剂量组和乌司他丁大剂量组,采用改良线栓法制备大脑中动脉缺血-再灌注模型。缺血60min,再灌注24h后,采用Western blot和RT-q PCR来观察脑缺血后梗死侧皮质Nrf2和HO-1蛋白及基因表达变化,比较各组神经功能,脑梗死体积,脑组织含水量,梗死侧皮质丙二醛(MDA)和超氧化物歧化酶(SOD)含量。结果乌司他丁能够明显上调缺血脑皮质组织Nrf2、HO-1的表达,增加SOD活性,减少MDA的含量,改善神经功能缺失,减轻脑水肿,减小梗死体积。结论 Nrf2/HO-1通路参与了脑梗死后乌司他丁对缺血脑组织的保护作用。     

G-CSF对局灶脑缺血再灌注大鼠脂质过氧化及神经细胞凋亡的影响

目的研究G-CSF对局灶脑缺血再灌注大鼠缺血区域脑组织脂质过氧化及神经细胞凋亡的影响,为G-CSF应用于缺血性脑血管病的治疗提供进一步的理论依据。方法 18只成年雄性Wistar大鼠随机分成3组:假手术组、盐水对照组和G-CSF治疗组,每组各6只大鼠。改良线栓法建立右侧大脑中动脉阻塞模型(t MCAO)。再灌注2 h后,G-CSF治疗组给予50μg/kg粒细胞集落刺激因子皮下注射一次;盐水对照组注入等量生理盐水;假手术组不作任何处理。再灌注24 h后处死大鼠取脑,化学比色法检测缺血区域SOD、GSH-PX、MDA、NO的含量;免疫组化染色计数p-JNK、p-p38MAPK阳性细胞;Tunel染色检测神经细胞凋亡情况。结果再灌注24 h后,G-CSF治疗组缺血区域SOD、GSH-PX的含量高于盐水对照组而低于假手术组(P<0.05),MDA、NO的含量低于盐水对照组而高于假手术组(P<0.05);G-CSF治疗组p-JNK、p-p38MAPK阳性细胞明显少于盐水对照组(P<0.05),tunel染色可见凋亡细胞数较盐水对照组减少。结论 G-CSF可以显著增加大鼠局灶脑缺血再灌注后SOD、GSH-PX的水平,减轻脂质过氧化反应程度,并且可以通过拮抗JNK、p38MAPK途径减轻神经细胞凋亡,发挥神经保护作用。     

β-七叶皂甙钠对脑缺血-再灌注损伤大鼠自由基的影响

目的探讨β-七叶皂甙钠在大鼠脑缺血-再灌注损伤时对自由基的影响。方法用Wistar大鼠45只制备局灶性脑缺血-再灌注模型,分为假手术组、缺血-再灌注组、β-七叶皂甙钠治疗组,每个组又分为缺血2 h后再灌注6 h、12 h、24 h三个时间点,每组每个时间点5只大鼠,术后观察脑组织梗死面积、大鼠的神经行为学变化评分、脑组织超微病理结构变化、脑组织TTC染色,对缺血区脑组织超氧化物歧化酶(superoxide dismutase,SOD)、丙二醛(malondiadehyde,MDA)含量进行测定和分析。结果假手术组相应时间点神经功能损害评分显著低于缺血-再灌注组和治疗组(P<0.05),治疗组SOD含量明显高于缺血-再灌注组各时间点(P<0.05)。光镜显示假手术组脑组织结构未见明显病理改变,脑缺血-再灌注组神经细胞缺血坏死,细胞水肿明显,胶质细胞弥漫增生,炎性细胞浸润。结论自由基参与了脑缺血-再灌注损伤,β-七叶皂甙钠可降低缺血-再灌注后脑组织中MDA的含量,增加SOD的活性,减轻梗死体积,显著减轻大鼠神经功能损害和脑组织水肿,对局灶性脑缺血-再灌注损伤具有一定的保护作用。     

通心络胶囊对大鼠脑缺血再灌注损伤的保护作用及其机制

目的 研究通心络胶囊对大鼠缺血再灌注损伤的保护作用及其作用机制.方法 99只SD大鼠随机分为通心络治疗组、通心络预防组及未用药对照组,线栓法建立缺血2 h再灌注损伤模型,再灌注后1 h、1 d和5 d断头取脑.TTC测定脑梗死体积;干湿法计算脑含水量;电镜观察海马神经元超微结构;羟胺法检测SOD含量;TBA法检测MDA含量;比色法检测GSH-PX、钠-钾-ATP酶、NO含量;免疫荧光观察小胶质细胞活化情况.结果 在通心络药物干预下,大鼠脑梗死侧和梗死对侧含水量减少,脑梗死体积减小,缺血性海马神经细胞坏死肿胀减轻,SOD、GSH-PX和钠-钾-ATP酶含量增加,MDA、NO含量降低(P<0.05),小胶质细胞的表达减少.结论 通心络胶囊可能通过调节自由基、减轻钙内流和抑制炎症反应的作用机制减轻脑缺血再灌注损伤.     

人白介素-10基因转染对脑缺血再灌注损伤大鼠脑组织中NO、SOD、MDA、GSH-Px的影响

目的观察人白介素-10(IL-10)基因转染对局灶脑缺血再灌注损伤大鼠脑组织中一氧化氮(NO)、超氧化物歧化酶(SOD)、丙二醛(MDA)、谷胱甘肽过氧化物(GSH-Px)的影响,探讨其缺血脑保护的作用机制。方法实验分正常对照组、缺血对照组、人IL-10基因转染组和空质粒组,采用Longa法建立大脑中动脉栓塞(MCAO)模型,采用立体定向脑室内注射的方式进行转染,然后分别用逆转录-聚合酶链式反应(RT-PCR)和酶联免疫吸附实验(ELISA)检测其转染效果,氯化三苯四氮唑(TTC)染色测定脑梗死体积,Longa 5分制进行神经行为学评分,同时按照试剂盒说明分别检测脑组织中NO、SOD、MDA、GSH-Px的含量。结果(1)人IL-10基因能有效整合到大鼠脑组织中并能高效分泌人IL-10,同时人IL-10基因转染能减少脑梗死体积和降低神经行为学评分;(2)正常对照组、缺血对照组、空质粒组和人IL-10基因转染组SOD的含量分别为214.28±13.73、170.69±12.26、175.20±13.76和195.77±13.20U/mgprot。GSH-Px的含量分别为25.73±1.72、19.91±1.81、19.32±1.37和22.70±2.22U/mgprot。与正常对照组相比,缺血对照组、空质粒组和人IL-10基因转染组SOD和GSH-Px的含量明显下降(P(0.01)。人IL-10基因转染组SOD和GSH-Px的含量则较缺血对照组、空质粒组明显升高(P(0.01)。缺血对照组和空质粒组之间无显著差异(P>0.05)。(3)正常对照组、缺血对照组、空质粒组和人IL-10基因转染组MDA的含量分别为6.29±0.33、8.75±0.44、8.66±0.51和7.70±0.31nmol/mgprot。NO的含量分别为1.07±0.11、1.87±0.18、1.93±0.33和1.44±0.10μmol/gprot。与正常对照组相比,缺血对照组、空质粒组和人IL-10基因转染组MDA和NO的含量明显升高(P(0.01)。人IL-10基因转染组MDA和NO的含量则较缺血对照组、空质粒组显著下降(P(0.01)。缺血对照组和空质粒组之间无显著差异(P>0.05)。结论人IL-10基因转染能降低大鼠局灶脑缺血再灌注损伤脑组织中MDA和NO的含量,同时能提升SOD和GSH-Px的含量,可能是其发挥缺血脑保护作用的机制之一。     

左归丸对大鼠慢性脑缺血线粒体呼吸链酶复合物活性的影响

目的探讨左归丸对慢性脑缺血线粒体呼吸链酶复合物活性的影响及其机制。方法将实验大鼠随机分为对照组、假手术组、慢性脑缺血组和左归丸治疗组,各8例。后两组大鼠采用双侧颈总动脉结扎法建立慢性脑缺血大鼠模型。左归丸治疗组于术后3周开始每天予以左归丸液灌胃,剂量为4.0 g/kg/d。术后6周,测试各组大鼠脑皮质线粒体活性氧(ROS)水平及线粒体呼吸链酶复合物活性测定。结果与对照组及假手术组比较,慢性脑缺血组大鼠的脑的线粒体ROS水平明显增高(P0.01),呼吸链酶复合物Ⅰ-Ⅳ活性均有不同程度的明显降低(P0.01);接受左归丸治疗组的大鼠的脑的线粒体ROS水平明显降低(P0.05),呼吸链酶复合物Ⅳ(COX)活性得到明显改善(P0.05)。结论左归丸可能通过修复线粒体COX的活性水平,改善线粒体功能,减少ROS的生成,从而起到对慢性缺血的保护作用。     

慢性脑缺血大鼠海马PARP、MDA的表达及阿魏酸钠的抗氧化作用

目的研究慢性脑缺血大鼠海马聚腺苷二磷酸核糖聚合酶(PARP)的表达,并探讨阿魏酸钠在慢性脑缺血所致的氧化应激性损伤中的作用。方法28只成年大鼠用于实验,10只采用双侧颈总动脉结扎制备大鼠慢性脑缺血模型,10只在颈总动脉结扎后给立即予阿魏酸钠腹腔注射,另8只为假手术组。2月后取大鼠海马,采用硫代巴比妥酸法检测丙二醛(MDA)含量,用免疫印迹的方法检测PARP蛋白的表达量。结果慢性脑缺血大鼠海马MDA及PARP蛋白含量明显增多,而经阿魏酸钠治疗后,MDA含量下降,PARP表达下调。结论慢性脑缺血可诱导内源性氧化应激使自由基增多,产生脂质过氧化损伤作用,并导致DNA链的断裂,激活PARP的表达;阿魏酸钠可减少MDA和PARP的生成,在慢性脑缺血氧化应激中起保护作用。     

依达拉奉对慢性脑低灌注大鼠脑自由基代谢及海马CA1区HIF-1α表达的影响

目的:观察依达拉奉对慢性脑低灌注大鼠前脑组织SOD、MDA代谢变化及海马CA1区HIF-1α表达的影响,并探讨其意义。方法:实验分假手术组,模型组及依达拉奉组,后两组采用永久性大鼠双侧劲总动脉结扎术(2-vesselocclusion,2VO)制备慢性脑低灌注模型,各组在术后八周后行水迷宫试验后断头,取前脑组织制备成10%脑组织匀浆检测其SOD活性及MDA含量,并采用免疫组化技术观察海马CA1区HIF-1α表达变化。结果:模型组与假手术组相比水迷宫完成时间显著延长(P<0.05),前脑组织SOD活性降低,MDA含量增加(P<0.01),海马CA1区可见HIF-1α少量表达。依达拉奉组较模型组水迷宫结果显著改善(P<0.01),前脑组织SOD活性增加,MDA含量减少(P<0.01),且海马CA1区可见HIF-1α大量表达。结论:慢性脑低灌注可显著损害大鼠空间学习记忆能力,依达拉奉可能通过抑制黄嘌呤氧化酶和次黄嘌呤氧化酶活性,降低羟自由基的浓度,促进HIF-1α表达等多种途径改善血管性认知障。     

Paeoniflorin attenuates chronic cerebral hypoperfusion-induced learning dysfunction and brain damage in rats

Chronic cerebral hypoperfusion, a mild ischemic condition, is associated with the cognitive deficits of AD. Paeoniflorin (PF), a major constituent of peony root, was proved to be neuroprotective in middle cerebral artery occlusion model. In this study, we investigated whether PF could attenuate chronic cerebral hypoperfusion-induced learning dysfunction and brain damage in rat. Seven weeks after permanent bilateral occlusion of the common carotid arteries, the rats were tested in the Morris water maze. Subsequently, the animals were sacrificed and neurons, astrocytes and microglias were labeled with immunocytochemistry in hippocampus. PF at the dose of 2.5 mg/kg ameliorated cerebral hypoperfusion-related learning dysfunction and prevented CA1 neuron damage. Chronic cerebral hypoperfusion increased the immunoreactivity of astrocytes and microglias in hippocampus. The increase was prevented by PF at the dose of 2.5 mg/kg. Cerebral hypoperfusion also increased expression of nuclear factor-kappaB (NF-kappaB), mostly in astrocytes, but not in neurons. With the treatment of PF (2.5 mg/kg), NF-kappaB immunostaining was diminished in hippocampus. Our results demonstrated that PF could attenuate cognitive deficit and brain damage induced by chronic cerebral hypoperfusion and that suppression of neuroinflammatory reaction in brain might be involved in PF-induced neuroprotection.     

氧化应激在慢性缺血性脑白质损伤中的作用

目的 阐明氧化应激是否参与大鼠慢性脑缺血所致的脑白质损伤.方法 健康雄性Wistar大鼠按照完全随机数字表法分为假手术组,持久性双侧颈总动脉结扎3 d组、7 d组、3周组及6周组,每组6只.应用大鼠双侧颈总动脉结扎制备慢性脑缺血模型,检测大鼠脑白质内超氧化物歧化酶(SOD)活性、过氧化氢酶(CAT)活性、谷胱甘肽(GSH)含量以及脂质过氧化产物丙二醛(MDA)和4-羟基壬烯醛(4-HNE)加合物的变化.结果 与假手术组比较,慢性脑缺血大鼠脑白质内MDA含量在手术后3周明显增加,手术后6周进一步增高,差异有统计学意义(P<0.05).手术后3d至6周,慢性脑缺血大鼠脑白质内4-HNE蛋白加合物逐渐增高,与假手术组比较有差异有统计学意K(P<0.05).SOD活性在手术后3周和6周才明显降低,与假手术组比较差异有统计学意义(P<0.05).此外,慢性脑缺血大鼠脑白质内GSH含量在手术后7d即开始降低,而在手术后3周及6周则进一步下降,与假手术组比较差异有统计学意义(P<0.05).结论 慢性脑缺血导致大鼠脑白质氧化性损伤增加,抗氧化防御能力降低:氧化性损伤的增加和抗氧化防御能力的降低与慢性脑缺血所致的脑白质损伤密切相关.     

下调PAR-1对脑出血模型大鼠的干预效果及作用机制

目的 探讨下调蛋白酶激活受体-1(Proteinase activated receptor-1,PAR-1)对脑出血模型大鼠的干预效果及相关作用机制。 方法 选取40只健康清洁级雄性大鼠,建立脑出血模型,分为假手术组10只,模型组、对照(pcDNA3-PARls)组、下调PAR-1(PcDNA3-PARlas)组各9只,表达载体构建,评估神经功能评分,检测脑水肿体积、脑组织含水量,脑组织HE染色,检测丙二醛(Malondialdehyde,MDA)水平、超氧化物歧化酶(Superoxide dismutase,SOD)活性、炎症因子及PAR-1相对表达水平。结果 模型组、对照组、下调PAR-1组神经功能评分、脑组织含水量、MDA水平,MMP-9,TNF-α,IL-1β,PAR-1相对表达水平高于假手术组,SOD活性低于假手术组(P<0.05); 对照组神经功能评分、脑水肿体积、脑组织含水量、MDA水平,MMP-9,TNF-α,IL-1β,PAR-1相对表达水平高于模型组,SOD活性低于模型组(P<0.05); 下调PAR-1组神经功能评分、脑水肿体积、脑组织含水量、MDA水平,MMP-9,TNF-α,IL-1β,PAR-1相对表达水平低于模型组和对照组,SOD活性高于模型组和对照组(P<0.05)。结论 下调PAR-1对脑出血模型大鼠干预效果显著,能减轻大鼠脑水肿,可能通过下调PAR-1表达来降低MMP-9,TNF-α,IL-1β水平和调控氧自由基代谢,从而对脑出血后的脑组织起到一定的保护作用。     

PI3K/AKT信号通路介导脂联素对脑缺血再灌注大鼠的保护作用

目的 探讨磷脂酰肌醇3激酶/蛋白激酶B（phosphatidylinositol-3-kinase/protein kinase B,PI3K/PKB）信号通路介导脂联素对脑缺血再灌注大鼠的保护作用。 方法 随机将SD大鼠分为假手术组、模型组、脂联素治疗组和PI3K/PKB抑制剂LY294002组（抑制剂组）,每组15只。通过线栓法构建大脑中动脉缺血模型,缺血1.5?h后再灌注。脂联素治疗组在再灌注2?h后,给予大鼠尾静脉注射脂联素（180?μg/100?g）;抑制剂组在再灌注2?h后给予大鼠尾静脉注射脂联素（180?μg/100?g）+LY294004（0.03?mg/100?g）;假手术组和模型组尾静脉注射相应体积的0.9%生理盐水（0.09?mL/100?g）。各组缺血再灌注24?h后,检测各组大鼠脑梗死面积和脑含水量;采用Longa 5分法进行神经功能缺损评分;蛋白质印迹法（Western blotting）检测大鼠脑组织PI3K、PKB、磷酸化的蛋白激酶B（phosphorylated PKB,p-PKB）和脂联素蛋白表达水平;酶联免疫吸附（enzyme linked immunosorbent assay,ELISA）法检测大鼠血清丙二醛（malondialdehyde,MDA）和超氧化物歧化酶（superoxide dismutase,SOD）水平。 结果 与假手术组相比,模型组大鼠的脑梗死面积、脑含水量、神经功能缺损评分和MDA水平均升高（均P<0.001）,SOD、脂联素、PI3K和p-PKB的表达水平均降低（均P<0.001）。与模型组比较,脂联素治疗组大鼠脑梗死面积、脑含水量、神经功能缺损评分和MDA水平均降低（均P<0.001）,SOD、脂联素、PI3K和p-PKB表达水平均升高（均P<0.001）;与脂联素治疗组比较,抑制剂组大鼠脑梗死面积、脑含水量、神经功能缺损评分和MDA水平均升高（均P<0.001）,SOD、脂联素、PI3K和p-PKB表达水平均降低（均P<0.001）。 结论 脂联素对脑缺血再灌注有明显保护作用,该保护机制可能与激活PI3K/PKB信号通路抑制氧化应激相关。     

The pre-treatment effect on brain injury during restoration of normal perfusion pressure with hemodilution in a new rat model of chronic cerebral hypoperfusion

OBJECTIVES: To investigate the effect of hemodilution with high-concentration human serum albumin (HSA) on brain injury in a rat model of chronic cerebral hypoperfusion associated with arteriovenous malformations. METHODS: The animal model was established by creating a fistula through an end-to-side anastomosis between the right distal external jugular vein and the ipsilateral common carotid artery, followed by ligation of the left vein draining the transverse sinus and bilateral external carotid arteries. The agent (20% HSA) or control solution (0.9% sodium chloride) was administered intravenously at a dosage of 1% body weight 24 hours before ligation of the fistula. Blood-brain barrier (BBB) disruption was judged by extravasation of Evans blue (EB) dye. EB, water content and the changes of myeloperoxidase (MPO) activity and superoxide dismutase (SOD) activity in rat brains 24 hours after ligation of the fistula were determined. RESULTS: EB and water content in rat brains of the pre-treated group were significantly decreased compared with the control group accompanied by reduction of MPO activity and enhancement of SOD activity. DISCUSSION: Hemodilution with high-concentration HSA has a certain pre-treatment effect on brain injury after ligation of the fistula in rat model of chronic cerebral hypoperfusion, which may be resulted from improved microcirculation, decrease in inflammatory cell infiltration and inactivation of oxygen free radicals.     

Chronic cerebral hypoperfusion protects against acute focal ischemia, improves motor function, and results in vascular remodeling

Atherosclerosis may cause severe stenosis of the arteries supplying the brain, which induces chronic cerebral hypoperfusion. Although an infarction often occurs in this area, it is uncertain how brain vessels respond to the chronic hypoperfusion or how the vascular responses are related to stroke severity when the area has been subjected to severe ischemia. To address these uncertainties, we induced chronic cerebral hypoperfusion in Sprague-Dawley rats with a bilateral common carotid artery ligation (BCAL). A middle cerebral artery occlusion/reperfusion (MCAO/R) was introduced with a nylon suture four weeks after either BCAL (BCAL-MCAO) or a sham operation (Sham-MCAO). Motor disability scores and infarct sizes, based on 2,3,5-triphenyltetrazolium chloride staining, were significantly reduced with BCAL-MCAO treatment compared with sham-MCAO treatment (P<0.01). The diameters of the posterior cerebral, posterior communicating, and basilar arteries on the brain surface were larger and more tortuous in BCAL-treated rats (P<0.01). The density of large capillary- and arteriole-sized vessels in the brain parenchyma also increased in BCAL-treated rats (P<0.05). Strokes were less severe when the vicinity subjected to infarction was preconditioned with chronic cerebral hypoperfusion. Increasing the vascular reserve with adaptive vascular remodeling may have contributed to this response.     

Chronic cerebral hypoperfusion and reperfusion injury of restoration of normal perfusion pressure contributes to the neuropathological changes in rat brain

Restoration of normal perfusion pressure after resection of cerebral arteriovenous malformations (AVMs) is sometimes complicated by unexplained postoperative brain swelling and/or intracranial hemorrhage, which has been termed normal perfusion pressure breakthrough (NPPB). The precise mechanism of NPPB is still unclear. In this study, we investigated the time courses of blood-brain barrier (BBB) disruption, water content, neuronal apoptosis, myeloperoxidase (MPO) activity and superoxide dismutase (SOD) activity in the brain during restoration of normal perfusion pressure in a new rat model of chronic cerebral hypoperfusion associated with AVMs. Male Sprague-Dawley rats were randomly divided into either a sham-operated group, a control group, or a model group with reperfusion assessed at 1, 12, 24 and 72 h after restoration of normal perfusion pressure. BBB disruption was judged by extravasation of Evans blue (EB) dye. We observed that EB and water content in rat brains of the model group with reperfusion were significantly increased compared with the other groups. The most predominant increase occurred at 1 h after reperfusion, and the next at 24 h after reperfusion, representing biphasic changes which are similar to the pathological processes of acute cerebral ischemia/reperfusion injury. There was no difference of the percentage of apoptotic cells in rat brains between the sham-operated group and the control group using flow cytometry. No prominent apoptotic cells were found in the model group with reperfusion at 1 h. However, the percentage of apoptotic cells increased significantly in rat brains of the model group with reperfusion at 12 h, peaked at 24 h, and decreased at 72 h after reperfusion. Apoptotic cells were confirmed with electron microscopy and terminal deoxynuleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL). A significant enhancement of MPO activity in combination with reduction of SOD activity was seen at 12, 24 and 72 h in rat brains of the model group with reperfusion. Our data indicates that reperfusion after restoration of normal perfusion pressure with chronic cerebral hypoperfusion lead to secondary neuronal damage which may associate with cerebral ischemia/reperfusion injury.     

妥泰对沙土鼠脑缺血再灌注损伤保护作用的实验研究

目的 研究妥泰对沙土鼠脑缺血再灌注损伤的保护作用及作用机制。方法 采用沙土鼠双侧颈总动脉结扎制成的全脑缺血模型。56只沙土鼠随机分为假手术组、缺血组、治疗组和预防组。预防组的动物分别给予大、小剂量的妥泰(100 mg/kg、50mg/kg)灌胃观察3天而行手术,术后24小时处死动物;治疗组的动物术后立即分别给于大、小剂量的妥泰(100 mg/kg、50mg/kg)灌胃观察7天处死动物。测定各组沙土鼠血、脑组织中的MDA、SOD的含量。光镜和电镜下观察脑组织CA_1区的病理及超微结构改变。结果 与缺血组相比,妥泰治疗组和妥泰预防组脑组织中的MDA含量明显降低(P<0.01),而SOD含量明显增高(P<0.01)。光镜和电镜下观察发现,妥泰治疗组和妥泰预防组的脑CA_1区缺血改变较缺血组减轻,且大剂量组缺血改变明显减轻。结论 妥泰对沙土鼠脑缺血再灌注损伤具有良好的保护作用,且保护作用与妥泰的剂量大小有关。其脑保护作用机制之一为妥泰能有效抑制氧自由基的产生及毒性。