实验性局灶性脑缺血不同脑区VEGF、VEGFR-1、2表达及意义

目的 通过探索血管内皮生长因子及其受体在局灶性脑缺血中的表达，进而探求血管内皮生长因子在局灶性脑缺血中的作用。方法 应用左侧颈总动脉结扎加缺氧诱导的方法，建立SD大鼠永久大脑中动脉闭塞模型，应用免疫组化方法检测血管内皮生长因子及其受体(VEGF、VEGFR-1、2)的表达，同时观察局灶性脑缺血后血管型成情况。结果 VEGF及VEGFR-1、2在局灶性脑缺血后6h表达增强，24h达高峰，在1周、2周恢复到对照水平。VEGF主要在缺血半影区(IP)神经元、胶质细胞及血管内皮细胞表达；VEGFR-1、2主要在缺血半影区血管内皮细胞表达。在缺血后48h半影区周边出现血管增生，1周后达高峰。结论 在局灶性脑缺血早期VEGF及VEGFR-1、2在神经细胞、胶质细胞、血管内皮细胞等均有表达，可促进缺血半影区的血管增生，对改善缺血半影区血供有重要作用。     

糖尿病脑梗死大鼠血管内皮生长因子及其受体表达水平的变化

目的 研究糖尿病脑梗死(DMCI)早期半暗带等值区血管内皮生长因子(VEGF)及其受体(FLT-1,FLK-1)表达水平的变化.方法 建立DMCI大鼠模型,在脑缺血后1 h、3 h、6 h、12 h、24 h,采用原位杂交方法测定大鼠大脑缺血半暗带等值区VEGF、FLT-1、FLK-1 mRNA的表达水平;并与无糖尿病的脑梗死(NDMCI)大鼠比较.结果 DMCI组在脑缺血后各时间点脑缺血半暗带等值区VEGF mRNA的表达水平均显著低于NDMCI组(P＜0.05～0.01),FLK-1 mRNA表达水平在脑缺血后12 h显著低于NDMCI组(P＜0.01),FLT-1 mRNA表达水平在脑缺血后各时间点(除6 h)与NDMCI组差异无统计学意义.结论 DMCI早期VEGF和FLK-1 mRNA表达水平降低,这可能是DMCI血管、神经病变重的原因之一.     

大鼠局灶性脑缺血再灌注ICRmRNA表达动态变化研究

目的 探讨白细胞介素1-β转化酶（ICE）在局灶性脑缺血再灌注后的表达及作用。方法 线栓法复制大脑中动脉脑缺血再灌注模型。逆转录聚合酶链式反应（RT-PCR）技术检测大鼠局灶性脑缺血再灌注后ICEmRNA表达。结果 缺血3h及缺血3h再灌注随缺血及缺血再灌注时间延长,缺血中心区与半影区ICEmRNA表达处于动态变化之中,再灌注24h、48h半影区表达持续高水平,而中心区表达下降。结论 局灶性脑缺血再灌注过程中ICEmRNA表达增强,促进神经细胞凋亡,ICE参与局灶性脑缺血再灌注神经细胞凋亡的调控。     

大鼠局灶性脑缺血后再灌注期caspase—9 mRNA及Apaf—1mRNA表达的动态变化

目的探讨大鼠局灶性脑缺血后再灌注期caspase-9 mRNA及Apaf-1 mRNA表达的动态变化.方法采用线栓法制作大鼠局灶性脑缺血后再灌注模型,以逆转录聚合酶链式反应(RT-PCR)技术检测caspase-9 mRNA及Apf-1 mRNA的表达.结果缺血2 h后再灌注,缺血皮质中caspase-9 mRNA的表达在再灌注后24h达高峰,48h仍保持高水平,而Apaf-1 muRNA的表达无明显改变.结论局灶性脑缺血后再灌注48h内caspase-9 mRNA表达增强.     

大鼠局灶脑缺血中心区与边缘区VEGF表达及mRNA变化

目的 探讨VEGF、VEGFmRNA在局灶脑缺血中心区和边缘区的表达和动态变化。方法 SD大鼠54只。根据缺血时间和再灌时间分为9组，采用线栓并环扎的方法建立局灶脑缺血再灌模型。LSAB法免疫组化染色观察VEGF免疫阳性表达。RT—PCR法检测VEGFmRNA动态变化。结果 在缺血3～6h，缺血中心区与边缘区VEGF免疫阳性反应达高峰，VEGFmRNA转录水平明显升高，两者24h基本降至正常水平。结论 VEGF在缺血早期的高表达可能与神经细胞和内皮细胞的自身保护作用有关。     

脑缺血再灌注后血管内皮细胞凋亡及其与Bcl—2表达的关系

目的 探讨大鼠局灶性脑缺血再灌注损伤后血管内皮细胞凋亡及其与Bcl-2蛋白表达的关系。方法 采用原位末端标记法和免疫组化法分别观察脑缺血再灌注2h、6h、12h、24h、2d、3d、7d、14d和21d等时间 点血管内皮细胞凋亡和Bcl-2蛋白的表达。结果 （1）脑缺血再灌注2h在缺血周围区即有凋亡内皮细胞出现,12－24h达高峰,之后逐渐下降,至21d与假手术组已无显著性差异。（2）脑缺血再灌注后2h在缺血周围区内皮细胞Bcl-2开始表达,12－24h达高峰,之后逐渐下降,至14d接近假手术组水平。（3）Bcl-2蛋白表达时相变化与内皮细胞凋亡基本一致。结论 脑缺血再灌注损伤中凋亡是血管内皮细胞的死亡形式之一,Bcl-2蛋白具有抑制缺血再灌注后血管内皮细胞凋亡的作用。     

大鼠局灶性脑缺血皮质白细胞介素1β mRNA的表达

目的:观察大鼠局灶性脑缺血皮质白细胞介素1β(IL-1β)mRNA及其受体和受体拮抗剂表达的动态变化。方法:采用尼龙线栓法大鼠脑缺血模型,逆转录PCR方法观察缺血后其相对表达量。结果:缺血侧IL-1βmRNA在各缺血时间点皆有表达,12～24 h达高峰;IL-1RA在缺血48 h表达最强;IL-RI在缺血侧和缺血对侧均稳定表达(包括假手术组);IL-RⅡ仅在缺血侧有表达,24～48 h表达较高。结论:局灶性脑缺血时IL-1βmRNA表达增高,其受体及受体拮抗剂mRNA表达亦增高;表达程度与时相的差别说明它们在脑缺血中可能起着不同的作用。     

大鼠脑缺血再灌注后ICAM-1的表达与白细胞浸润关系的研究

目的 研究大鼠局灶性脑缺血再灌注后脑组织中细胞间粘附分子－1（ICAM－1）的表达与白细胞浸润的关系，并探讨亚低温的治疗作用。方法 采用大鼠大脑中动脉阻断（MCAO）模型，经免疫组化及HE染色，测定ICAM－1表达阳性微血管数及白细胞计数。结果 （1）脑缺血再灌注后，脑缺血坏死周边区的微血管内皮细胞表达ICAM－1及白细胞浸润增多，并于24h达到高峰，二者之间呈正相关（P＜0．01）；（2）缺血早期进行亚低温治疗能明显减轻缺血再灌注后ICAM－1的表达及减少白细胞浸润（P＜0．01）。结论 脑缺血再灌注后ICAM－1可介导白细胞和内皮细胞的粘附；亚低温干预治疗可减轻缺血再灌注后脑组织的损害。     

局灶脑缺血恢复期半影区小胶质细胞可塑性变化和bFGF表达规律探讨

目的 观察Wistar大鼠大脑中动脉永久性闭塞后不同时段，缺血半影区小胶质细胞和神经元形态学变化及bFGF在皮层和海马的表达规律。方法 将雄性Wistar大鼠48只，随机分为假手术对照组和永久性局灶性脑缺血组，后者再根据缺血时间不同分5个亚组。假手术组：仅暴露大脑中动脉，2h后断头取脑。永久性局灶性脑缺血组：建立大鼠大脑中动脉闭塞模型，分别于缺血后3d、7d、14d、28d、42d断头取脑，行HE和免疫组化染色。观察梗死灶周围半影区的小胶质细胞和神经元的形态学变化和bFGF在皮层及海马部位的表达规律。结果 HE染色可见脑缺血3d时半影区有少量小胶质细胞出现，14d小胶质细胞增多达高峰，42d趋于稳定。脑缺血3d梗死灶周围皮质神经元和胶质细胞开始表达bFGF，7d表达增强，14d达高峰，28d表达开始减弱，42d仍有一定表达，bFGF在海马的表达也有相同规律。结论 小胶质细胞的肥大和增生性变化以及bFGF的表达，不仅发生于脑缺血早期，晚期仍显示持续性变化，表明小胶质细胞活动以及bFGF的表达贯穿于脑缺血的整个病理过程。     

β-七叶皂甙钠对大鼠局灶性脑缺血再灌注后NF-κB、ICAM-1、VCAM-1表达的影响

目的探讨大鼠局灶性脑缺血再灌注脑组织缺血区不同时间点NF-кB、ICAM-1、VCAM-1蛋白表达的变化,及β-七叶皂甙钠干预效果。方法采用大鼠大脑中动脉闭塞法(MCAO)制作局灶性脑缺血再灌注模型,用免疫组织化学方法观察大鼠脑缺血再灌注不同时间段,NF-кB、ICAM-1、VCAM-1蛋白的表达。并在大鼠于脑缺血前24h、1h及再灌注即刻分别腹腔给予β-七叶皂甙钠5mg/kg,2h MCAO,再灌注24h、48h后取脑,运用TTC染色测算脑梗死体积,免疫组化染色检测NF-кB、ICAM-1、VCAM-1蛋白表达,分析β-七叶皂甙钠的干预效应。结果(1)脑缺血后缺血区脑组织NF-кB及ICAM-1、VCAM-1表达均增加,NF-kB于再灌注后12～24h表达达高峰,Ⅰ- CAM-1于再灌注后24h表达达高峰,VCAM-1于再灌注后24～48h表达达高峰。(2)NF-кB的表达与血管内皮I- CAM-1、VCAM-1的表达呈正相关。(3)β-七叶皂甙钠能显著降低脑缺血再灌注后24h和48h缺血区NF-кB、ICAM- 1及VCAM-1的表达增加。(4)β-七叶皂甙钠能明显减轻脑缺血再灌注后的脑组织损伤,再灌注24h脑梗死体积减少41.8%。结论(1)脑缺血再灌注后NF-кB、ICAM-1、VCAM-1大量表达,这可能是脑缺血再灌注损伤机制之一。(2)脑缺血后NF-кB的活化可能与微血管内皮细胞ICAM-1、VCAM-1蛋白表达调控有关。(3)β-七叶皂甙钠能够减轻脑缺血后的脑组织损伤,有神经保护作用。     

Cell type specific upregulation of vascular endothelial growth factor in an MCA-occlusion model of cerebral infarct.

Vascular endothelial growth factor (VEGF) is an endothelial cell specific mitogen that has been implicated in hypoxia-mediated angiogenesis under physiological and pathological conditions. We used the middle cerebral artery occlusion model (MCAO) in the rat to investigate VEGF mRNA and protein localization, and VEGFR-1 mRNA and VEGFR-2 mRNA expression in cerebral ischemia. By nonradioactive in situ hybridization we observed upregulation of VEGF mRNA and VEGFR-1 mRNA, but not of VEGFR-2 mRNA in the hemisphere ipsilateral to MCA occlusion. VEGF mRNA was upregulated in the periphery of the ischemic area commencing 3 hours (h) after onset of MCAO, reached a peak after 24 h, and remained expressed at lower levels until 7 days (d) after MCAO. Double labelling experiments revealed that the majority of VEGF expressing cells in the penumbra and within the infarct were immunoreactive for Ox-42, Iba-1, and Ed1, but not for GFAP and neurofilament proteins, suggesting that microglial cells/macrophages are the major cell type expressing VEGE Since VEGF was also expressed in Ox-42 immunoreactive cells distant from the infarct (e.g. in the corpus callosum and hippocampus), activated microglial cells expressing VEGF may migrate towards the ischemic stimulus. VEGF protein was also detected on capillaries within the peri-ischemic area, suggesting that VEGF produced and secreted by microglial cells/macrophages binds to its receptors on nearby vascular endothelial cells and initiates an angiogenic response which counterbalances tissue hypoxia. Accordingly, apoptosis of neuroectodermal cells in the penumbra was highly depressed after the onset of angiogenesis. The spatial and temporal correlation between the induction of angiogenesis with VEGF and VEGFR-1 expression suggests that the ischemic upregulation of VEGF represents a physiological response of the brain to counterbalance hypoxia/ischemia in order to protect neuroectodermal tissue.     

局灶性缺血预处理对脑缺血大鼠血管内皮生长因子表达及血管形成的影响

目的：探讨血管内皮生长因子（VEGF）在脑缺血耐受中的作用及其与血管形成的关系。方法：Wistar大鼠线栓法阻塞大脑中动脉建立局灶性缺血预处理模型,并进行神经功能评分。随机分为假手术（对照组）、非缺血预处理（NIP）组和缺血预处理（IP）组,NIP和IP组再根据不同时间窗随机分成5个亚组。分别在缺血预处理后1、3、7、14和21 d进行再次缺血2 h再灌注22 h,然后取脑检测：TTC染色测定脑梗死体积,计数微血管密度,免疫组化检测CD34和VEGF蛋白表达,原位杂交法检测VEGF mRNA表达。结果：①组间比较：IP 1、3和7 d亚组脑梗死体积较NIP组明显减小（P〈0.01）,其神经行为缺损评分也明显降低（P〈0.05）;IP 3和7 d亚组脑微血管密度明显增高（P〈0.05）;IP 1、3和7 d亚组VEGF蛋白及mRNA表达明显增高（P〈0.05,P〈0.01）。②组内比较：IP 7 d亚组微血管在缺血灶周边区分布最为密集,脑微血管密度明显高于同组内其他亚组（P〈0.05）;IP 3和7 d亚组VEGF蛋白表达明显增高,VEGF mRNA表达在IP 1 d即开始升高,高峰出现在IP 3 d,持续至7 d。结论：缺血预处理诱导了脑缺血耐受,缺血预处理诱导的VEGF表达增加以及血管形成在脑缺血耐受中发挥重要作用。     

Activated microvessels express vascular endothelial growth factor and integrin alpha(v)beta3 during focal cerebral ischemia.

Both vascular endothelial growth factor (VEGF) and integrin alpha(v)beta3 play roles in angiogenesis. In noncerebral vascular systems, VEGF can induce endothelial integrin alpha(v)beta3 expression. However, it is unknown whether VEGF, like integrin alpha(v)beta3, appears in the initial response of microvessels to focal brain ischemia. Their coordinate expression in microvessels of the basal ganglia after middle cerebral artery occlusion (MCAO) in the nonhuman primate model was examined quantitatively. Cells incorporating deoxyuridine triphosphate (dUTP+) by the polymerase I reaction at 1 hour (n = 3), 2 hours (n = 3), and 7 days (n = 4) after MCAO defined the ischemic core (Ic) and peripheral regions. Both VEGF and integrin alpha(v)beta3 were expressed by activated noncapillary (7.5- to 30.0-microm diameter) microvessels in the Ic region at 1 and 2 hours after MCAO. At 7 days after MCAO, the number of VEGF+, integrin alpha(v)beta3+, or proliferating cell nuclear antigen-positive microvessels had decreased within the Ic region. The expressions of VEGF, integrin alpha(v)beta3, and proliferating cell nuclear antigen were highly correlated on the same microvessels using hierarchical log-linear statistical models. Also, VEGF and subunit alpha(v) messenger ribonucleic acids were coexpressed on selected microvessels. Here, noncapillary microvessels are activated specifically early during a focal cerebral ischemic insult and rapidly express VEGF and integrin alpha(v)beta3 together.     

Up-regulation of neuropilin-1 in neovasculature after focal cerebral ischemia in the adult rat.

During development, neuropilin-1 is a receptor for semaphorin 3a-mediated axonal guidance and for vascular endothelial growth factor (VEGF) promotion of angiogenesis. The authors measured neuropilin-1 expression in the adult ischemic brain using Northern blot, in situ hybridization, and immunohistochemistry. Neuropilin-1 mRNA was significantly up-regulated as early as 2 hours and persisted at least 28 days after focal cerebral ischemia. Acute up-regulation of neuropilin-1 mRNA primarily localized to the ischemic neurons. A marked increase in both mRNA and protein of neuropilin-1 was detected in endothelial cells of cerebral blood vessels at the border and in the core of the ischemic lesion 7 days after ischemia, and neuropilin-1 gene expression persisted on these vessels for at least 28 days after ischemia. In these areas, neovascularization was detected using three-dimensional reconstructed images obtained from laser scanning confocal microscopy. Activated astrocytes also exhibited neuropilin-1 immunoreactivity during 7 to 28 days of ischemia. Double immunofluorescent staining showed colocalization of neuropilin-1 and VEGF to cerebral blood vessels and activated astrocytes. These data suggest that in addition to its role in axonal growth, up-regulation of neuropilin-1, in concert with VEGF and its receptors, may contribute to neovascular formation in the adult ischemic brain.     

大鼠局灶性脑缺血β淀粉样前体蛋白mRNA在缺血半暗带的表达变化

目的 :研究大鼠局灶性脑缺血不同缺血时间皮质半暗带和中心区淀粉样前体蛋白 (APP)在转录水平表达规律。方法 :用线栓法建立大鼠局灶性脑缺血模型 ,剥取缺血半暗带及中心区皮质组织 ,采用半定量逆转录 聚合酶链式反应 (RT PCR) ,测定APPmRNA水平的变化。结果 :半暗带APPmRNA在缺血后 48h升高 ,缺血 72h达到高峰 ,缺血 1周后仍高于正常。缺血中心区APPmRNA在缺血后 72h和 96h高于正常水平。结论 :APPmRNA在缺血半暗带的表达上调 ,有可能加重缺血损伤。     

Correlation of VEGF and angiopoietin expression with disruption of blood-brain barrier and angiogenesis after focal cerebral ischemia.

In an effort to elucidate the molecular mechanisms underlying cerebral vascular alteration after stroke, the authors measured the spatial and temporal profiles of blood-brain barrier (BBB) leakage, angiogenesis, vascular endothelial growth factor (VEGF), associated receptors, and angiopoietins and receptors after embolic stroke in the rat. Two to four hours after onset of ischemia, VEGF mRNA increased, whereas angiopoietin 1 (Ang 1) mRNA decreased. Three-dimensional immunofluorescent analysis revealed spatial coincidence between increases of VEGF immunoreactivity and BBB leakage in the ischemic core. Two to 28 days after the onset of stroke, increased expression of VEGF/VEGF receptors and Ang/Tie2 was detected at the boundary of the ischemic lesion. Concurrently, enlarged and thin-walled vessels were detected at the boundary of the ischemic lesion, and these vessels developed into smaller vessels via sprouting and intussusception. Three-dimensional quantitative analysis of cerebral vessels at the boundary zone 14 days after ischemia revealed a significant (P < 0.05) increase in numbers of vessels (n = 365) compared with numbers (n = 66) in the homologous tissue of the contralateral hemisphere. Furthermore, capillaries in the penumbra had a significantly smaller diameter (4.8 +/- 2.0 microm) than capillaries (5.4 +/- 1.5 microm) in the homologous regions of the contralateral hemisphere. Together, these data suggest that acute alteration of VEGF and Ang 1 in the ischemic core may mediate BBB leakage, whereas upregulation of VEGF/VEGF receptors and Ang/Tie2 at the boundary zone may regulate neovascularization in ischemic brain.     

兔大脑中动脉阻断所致局灶性脑缺血脑组织内皮抑素蛋白及mRNA表达增加(英文)

目的内皮抑素(endostatin)是强烈的抗血管再生因子。本文探讨大脑中动脉闭塞 (middle cerebral artery occlusion, MCAO)致局灶性脑缺血后脑组织内皮抑素蛋白及mRNA基因表达的变化,同时检测缺血脑组织血管内皮生长因子(vascular endothelial growth factor,VEGF)的含量。方法24只新西兰白兔随机分为正常对照组(n=5)、假手术组(n=4)、缺血2小时组(n=5)、缺血24小时组 (n=5)及缺血48小时组(n=5)共5组。酶联免疫吸附试验测定VEGF含量,免疫组化分析内皮抑素蛋白变化,原位杂交检测内皮抑素mRNA表达。结果与对照组相比,MCAO局灶性脑缺血后内皮抑素蛋白和mRNA表达均明显增加,至少分别增加了50%(P<0.01)和70%(P<0.05),同时缺血脑组织VEGF含量也明显增加,至少增加了270%。结论缺血导致脑组织内皮抑素表达增加,且内皮抑素的增加与缺血后脑组织VEGF变化无相关性,但可能抑制脑缺血后的血管再生,从而加重脑缺血损伤。     

大鼠局灶性脑缺血半暗带葡萄糖转运子3 mRNA的表达

目的 研究大鼠局灶性脑缺血不同缺血时间皮质半暗带和中心区葡萄糖转运子3（GLUT3）转录水平的表达规律。方法 用插线法建立大鼠局灶性脑缺血模型，剥取缺血半暗带及中心区皮质组织，采用逆转录-聚合酶链反应（RT-PCR），测定GLUT3mRNA水平的变化。结果 缺血半暗带GLUT3mRNA在缺血3小时升高，24小时达到高峰，96小时后基本恢复正常。缺血中心区GLUT3mRNA在缺血后3小时有一短暂的升高，随后迅速下降呈低水平表达。结论 GLUT3在缺血半暗带的表达上调，有可能是机体对缺血损伤的保护性反应。     

兔大脑中动脉阻断所致局灶性脑缺血脑组织内皮抑素蛋白及mRNA表达增加

目的内皮抑素（endostatin）是强烈的抗血管再生因子。本文探讨大脑中动脉闭塞（middle cerebral artery occlusion,MCAO）致局灶性脑缺血后脑组织内皮抑素蛋白及mRNA基因表达的变化,同时检测缺血脑组织血管内皮生长因子（vascular endothelial growth factor,VEGV0的含量。方法24只新西兰白兔随机分为正常对照组（n=5）、假手术组（n=4）、缺血2小时组（n=5）、缺血24小时组（n=5）及缺血48小时组（n=5）共5组。酶联免疫吸附试验测定VEGF含量,免疫组化分析内皮抑素蛋白变化,原位杂交检测内皮抑素mRNA表达。结果与对照组相比,MCAO局灶性脑缺血后内皮抑素蛋白和mRNA表达均明显增加,至少分别增加了50％（P〈0．01）和70％（P〈0．05）,同时缺血脑组织VEGF含量也明显增加,至少增加了270％。结论缺血导致脑组织内皮抑素表达增加,且内皮抑素的增加与缺血后脑组织VEGF变化无相关性,但可能抑制脑缺血后的血管再生,从而加重脑缺血损伤。