大鼠局灶性脑缺血/再灌注后VEGF的变化对缺血脑组织的影响

目的观察血管内皮生长因子（VEGF）在大鼠局灶性脑缺血／再灌注（I／R）后表达的动态变化，探讨VEGF对脑缺血保护的作用机制。方法采用免疫组化技术。结果在局灶性脑I／R早期既有VEGF的阳性表达，随再灌注时间的延长，表达逐渐增强，于脑I／R48h达到最强。结论在局灶性脑缺血早期，VEGF既有明显的表达增强，说明VEGF的表达具有可诱导性，缺血损伤可诱导其表达增加。随着再灌注时间的延长，在缺血灶的周边有明显免疫阳性着色增多的小血管，进一步说明VEGF可以促进毛细血管的增生，从而起保护神经元的作用。     

苯扎贝特对脑缺血再灌注损伤大鼠HIF-1α、VEGF表达的影响

目的探讨过氧化物酶体增殖物激活受体(PPAR)激动剂苯扎贝特对大鼠局灶性脑缺血再灌注损伤后的保护作用及机制。方法制作大鼠局灶性脑缺血再灌注(MCAO)模型,观察苯扎贝特对脑梗死大鼠神经功能影响,免疫组化法观察低氧诱导因子-1α(HIF-1α)、血管内皮生长因子(VEGF)表达。结果脑缺血再灌注损伤后模型组和苯扎贝特干预组均出现不同程度的神经行为功能异常,与模型组相比苯扎贝特能够显著降低神经功能缺损,促进HIF-1α、VEGF的表达(P<0.05)。结论苯扎贝特可增加HIF-1α、VEGF的表达,从而对缺血再灌注损伤起到神经保护作用。     

辛伐他汀对大鼠脑缺血再灌注损伤细胞凋亡的影响

目的 探讨辛伐他汀对大鼠局灶性脑缺血再灌注损伤细胞凋亡的影响.方法 采用大脑中动脉缺血(MCAO)制备大鼠局灶性脑缺血再灌注模型,Longa 5分法对脑缺血再灌注损伤后各组大鼠进行神经功能评分,TUNEL法和电镜法观察脑缺血区细胞凋亡的情况.结果 辛伐他汀可以明显减少缺血区神经细胞的死亡,对大鼠局灶性脑缺血再灌注损伤后的细胞凋亡有明显的抑制作用.结论 辛伐他汀可抑制大鼠局灶性脑缺血再灌注损伤细胞凋亡.     

老年大鼠缺血再灌注脑组织血管内皮生长表达及地塞米松对其表达的影响

目的　探讨局灶性脑缺血再灌注后血管内皮生长因子 (VEGF)蛋白表达的意义及地塞米松对其影响。　方法　采用老年雄性大鼠短暂性大脑中动脉闭塞 (MCAO)与再灌注模型 ,应用免疫组织化学方法观察大脑中动脉闭塞 90min再灌注 1～ 7d脑组织VEGF蛋白的表达及腹腔内注射地塞米松 ( 2mg·kg-1 ·d-1 ,持续 7d)对VEGF蛋白表达及脑组织含水量的影响。　结果　实验大鼠再灌注1h ,缺血半暗带神经元及同侧大脑中动脉供血区软脑膜开始表达VEGF ,1d达峰值 (P <0 0 1) ,前者于 1d后快速下降 ,后者维持高水平至 7d。缺血半暗带脑血管内皮细胞在 1～ 7d也有较丰富VEGF表达 (P <0 0 1)。地塞米松处理组缺血区的脑微血管内皮细胞VEGF表达明显减少 (P <0 0 1)。地塞米松在缺血再灌注 1～ 7d明显减少缺血脑组织含水量 (P <0 0 5)。　结论　局灶性脑缺血再灌注可诱导VEGF表达 ,地塞米松可抑制缺血再灌注脑组织血管内皮细胞VEGF表达     

注射用丹参多酚酸盐在大鼠脑缺血再灌注损伤中的作用机制

目的探讨注射用丹参多酚酸盐在大鼠脑缺血再灌注损伤中的作用机制。方法将72只雄性SD大鼠随机分为Ⅰ组(Sham+生理盐水)、Ⅱ组(Sham+丹参多酚酸盐)、Ⅲ组(局灶性脑缺血+生理盐水)、Ⅳ组(局灶性脑缺血+丹参多酚酸盐)、Ⅴ组(局灶性脑缺血再灌注+生理盐水)和Ⅵ组(局灶性脑缺血再灌注+丹参多酚酸盐)。局灶性脑缺血为大脑中动脉阻塞(MCAO) 48 h;局灶性脑缺血再灌注为MCAO 2 h后再灌注48 h(MCAO/R)。MCAO模型制备采用改良Longa法,采用神经行为学评分法评价各组大鼠神经损伤情况; 2,3,5-氯化三苯基四氮唑(TTC)染色法检测各组大鼠脑梗死体积;采用免疫组化方法检测各组大鼠脑缺血半暗带血管内皮生长因子(VEGF)表达。结果Ⅰ组和Ⅱ组大鼠神经学表现正常,Ⅲ组和Ⅳ组大鼠神经学评分增高(P 0.05);与Ⅲ组和Ⅳ组比较,Ⅴ组和Ⅵ组大鼠神经学评分降低(P 0.05),且Ⅵ组低于Ⅴ组(P 0.05)。Ⅲ组和Ⅳ组大鼠有明显局灶性脑缺血,Ⅴ组和Ⅵ组大鼠脑梗死体积减小(P 0.05),且Ⅵ组大鼠梗死体积小于Ⅴ组(P 0.05)。免疫组化显示,Ⅴ组和Ⅵ组大鼠脑缺血半暗带VEGF阳性表达均增高(P0.05),而且Ⅵ组高于Ⅴ组(P 0.01)。结论丹参多酚酸盐可能通过VEGF在大鼠脑缺血再灌注损伤中发挥神经保护作用。     

黄体酮对大鼠局灶性脑缺血再灌注损伤后脑组织神经生长因子表达的影响

目的 观察黄体酮对大鼠局灶性脑缺血-再灌注损伤后缺血区皮层神经生长因子(NGF)和脑源性神经营养因子(BDNF)在mRNA与蛋白质水平表达的影响,探讨黄体酮在脑缺血-再灌注损伤中的脑保护作用机制. 方法 采用SD雄性大鼠局灶性脑缺血-再灌注损伤模型.将96只大鼠随机分为4组:假手术组、缺血再灌注组、溶剂组和黄体酮组各24只.应用Real time-PCR和Western blot技术分别对缺血区皮层NGF和BDNF mRNA与蛋白表达情况进行测定. 结果 在缺血区皮层,缺血2h再灌注6h后,缺血再灌注组NGF和BDNF的mRNA及蛋白质表达达高峰,再灌注24 h后,回复到假手术组水平;缺血2h再灌注12 h后,黄体酮组NGF和BDNF mRNA及蛋白表达达高峰,再灌注24 h后,表达仍高(P＜0.05). 结论 黄体酮可以使脑缺血-再灌注损伤后NGF和BDNF的mRNA表达上调,促进脑内NGF和BDNF蛋白的合成,从而发挥脑保护作用.     

缺血预适应对脑缺血再灌注大鼠皮质区血管内皮生长因子及存活素表达的影响

目的观察缺血预适应对局灶性脑缺血再灌注大鼠梗死灶周边皮质区血管内皮生长因子(VEGF)、存活素表达的影响,探讨其脑保护机制。方法 SD大鼠130只,随机分为假手术组10只、脑缺血组60只及预适应组60只,脑缺血组和预适应组按缺血后再灌注时间不同分为再灌注2、6、12、24、48和72h时间点,每个时间点10只。采用线栓法闭塞右侧大脑中动脉,制备大鼠局灶性脑缺血再灌注预适应模型。应用免疫组织化学法及Western blot检测观察梗死灶周边皮质区VEGF及存活素的表达。结果假手术组VEGF阳性细胞、存活素阳性细胞及皮质区VEGF蛋白和存活素蛋白表达较少。与脑缺血组比较,预适应组2、6、12、24、48和72hVEGF及存活素阳性细胞和蛋白表达明显升高(P<0.05,P<0.01)。结论脑缺血预适应可诱导VEGF和存活素表达上调,这可能是脑缺血预适应诱导脑缺血耐受的脑保护作用机制之一。     

糖尿病大鼠脑缺血再灌注后血管内皮生长因子及碱性成纤维细胞生长因子的表达

目的 研究糖尿病大鼠脑缺血再灌注后血管内皮生长因子(VEGF)、碱性成纤维细胞生长因子(bFGF)表达的情况.方法 采用STZ诱导产生慢性糖尿病大鼠模型,用线栓法制作大鼠脑缺血再灌注模型,对大鼠进行脑梗死体积计算并且采用免疫组化方法观察大鼠脑缺血再灌注不同时程(6,12,24,48 h)VEGF、bFGF的表达情况.结果 糖尿病组梗死体积明显大于正常血糖组;大鼠脑缺血再灌注6h,缺血侧脑组织梗死灶周边VEGF、bFGF免疫阳性反应已出现,12 h明显增多,24 h达高峰;糖尿病组在各时间点VEGF、bFGF表达比正常血糖组显著减少(P＜0.01).结论 脑缺血再灌注损伤后VEGF、bFGF表达增强,提示VEGF、bFGF对缺血性脑损伤有保护作用,可能与神经细胞和内皮细胞的自身保护作用有关.糖尿病加重了大鼠脑缺血再灌注损伤,造成VEGF、bFGF的表达不足.     

扶芳藤合剂预防给药对脑缺血后原癌基因C-fos表达的影响

目的观察扶芳藤、银杏叶合剂预防给药对局灶性脑缺血大鼠原癌基因C-fos表达的影响。方法采用免疫组化法检测大鼠脑缺血再灌注后不同时间点原癌基因C-fos表达的水平,观察各组实验大鼠脑缺血后C-fos表达水平的变化。结果大鼠脑缺血2h后再灌注不同时间点C-fos表达均升高,扶芳藤合剂预防给药可降低脑缺血再灌注后C-fos的表达。结论扶芳藤合剂预防给药,可能改善脑部血液循环,从而下调缺血脑组织C-fos蛋白表达,以减轻局灶性脑缺血后脑细胞的缺血性损伤。     

银杏叶提取物对大鼠局灶性脑缺血-再灌注损伤的神经保护作用

目的研究银杏叶提取物(EGB)对大鼠局灶性脑缺血-再灌注损伤的神经保护作用机制。方法采用改良线栓法建立大鼠大脑中动脉阻塞脑缺血-再灌注模型。实验动物随机分为假手术组、模型组、EGB治疗组。观察局灶性脑缺血2 h再灌注24 h后,大鼠神经行为学评分及神经元的变化。结果再灌注24 h后,与单纯缺血-再灌注组相比,给予EGB溶液注射可以改善动物的神经行为学评分、减轻神元损伤。结论 EGB对大鼠局灶性脑缺血-再灌注损伤具有神经保护作用。     

Expression and significance of angiostatin,vascular endothelial growth factor and matrix metalloproteinase-9 in brain tissue of diabetic rats with ischemia reperfusion

Objective: To discuss the expression and significance of angiostatin, vascular endothelial growth factor and matrix metalloproteinase-9 in the brain tissue of diabetic rats with ischemia reperfusion. Methods: A total of 60 male Wistar rats were randomly divided into the normal group, sham group, diabetic cerebral infarction group and single cerebral infarction group according to the random number table, with 15 rats in each group. The high sucrose diet and intraperitoneal injection of streptozotocin were performed for the modeling of diabetic rats, while the thread-occlusion method was employed to build the model of cerebral ischemia reperfusion. The immunohistochemical staining was performed to detect the expression of angiostatin, vascular endothelial growth factor(VEGF) and matrix metalloproteinase-9(MMP-9) in the brain tissue. Results: The expression of angiostatin after the reperfusion in the brain tissue of rats in the single cerebral infarction group and diabetic cerebral infarction group was increased 6 h after the reperfusion, reached to the peak on 1 d and then decreased gradually. The expression of angiostatin in the diabetic cerebral infarction group 6 h, 1 d, 3 d and 7 d after the reperfusion was significantly higher than that in the single cerebral infarction group(P0.05). VEGF began to be increased 1 h after the reperfusion in the single cerebral infarction group and diabetic cerebral infarction group, reached to the peak at 6 h and then decreased gradually. The expression of VEGF in the diabetic cerebral infarction group at each time point after the reperfusion was significantly lower than that in the single cerebral infarction group(P0.05). MMP-9 began to be be increased 1 h after the reperfusion in the single cerebral infarction group and diabetic cerebral infarction group, reached to the peak on 1 d and then decreased gradually. The expression of MMP-9 in the diabetic cerebral infarction group at each time point after the reperfusion was significantly higher than that in the single cerebral infarction group(P0.05). Conclusions: The high glucose environment in which the diabetic cerebral infarction is occurred is to induce the formation of MMP-9 at first and then activate and increase the expression of angiostatin. Afterwards, the expression of VEGF is inhibited, resulting in the poor angiogenesis after cerebral infarction, which thus makes the injury of brain tissue after cerebral infarction even worse than the non-diabetes mellitus.     

Nitric oxide enhances angiogenesis via the synthesis of vascular endothelial growth factor and cGMP after stroke in the rat

We investigated the effects of NO on angiogenesis and the synthesis of vascular endothelial growth factor (VEGF) in a model of focal embolic cerebral ischemia in the rat. Compared with control rats, systemic administration of an NO donor, DETANONOate, to rats 24 hours after stroke significantly enlarged vascular perimeters and increased the number of proliferated cerebral endothelial cells and the numbers of newly generated vessels in the ischemic boundary regions, as evaluated by 3-dimensional laser scanning confocal microscopy. Treatment with DETANONOate significantly increased VEGF levels in the ischemic boundary regions as measured by ELISA. A capillary-like tube formation assay was used to investigate whether DETANONOate increases angiogenesis in ischemic brain via activation of soluble guanylate cyclase. DETANONOate-induced capillary-like tube formation was completely inhibited by a soluble guanylate cyclase inhibitor, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxaline-1-one (ODQ). Blocking VEGF activity by a neutralized antibody against VEGF receptor 2 significantly attenuated DETANONOate-induced capillary-like tube formation. Moreover, systemic administration of a phosphodiesterase type 5 inhibitor (Sildenafil) to rats 24 hours after stroke significantly increased angiogenesis in the ischemic boundary regions. Sildenafil and an analog of cyclic guanosine monophosphate (cGMP) also induced capillary-like tube formation. These findings suggest that exogenous NO enhances angiogenesis in ischemic brain, which is mediated by the NO/cGMP pathway. Furthermore, our data suggest that NO, in part via VEGF, may enhance angiogenesis in ischemic brain.     

脑心通对大鼠脑缺血再灌注损伤后血管内皮生长因子表达的保护作用

目的探讨脑心通对大鼠脑缺血再灌注损伤后血管内皮生长因子（VEGF）表达的影响。方法将120只大鼠随机分为大鼠脑缺血6h开始用药组（A组），脑缺血12h开始用药组（B组），正常脑缺血再灌注损伤组（C组）及假手术对照组（D组），每组30例。每组大鼠在脑缺血6h再灌注12h、24h、48h、72h及7d时进行神经功能评分，然后采用免疫组织化学和原住杂交的方法观察大鼠脑缺血再灌注不同时间点VEGF的表达。结果脑缺血6h时，各组间神经功能评分无统计学意义，脑缺血再灌注不同时间点对各组进行神经功能评分发现，A组、B组大鼠神经功能评分明显低于C组；在缺血再灌注不同时间点免疫组织化学和原位杂交结果为，A组大鼠VEGF的表达明显高于B组和C组。结论脑心通促进了VEGF的表达，其通过促进VEGF的表达参与了脑缺血再灌注损伤的保护机制。     

Vascular endothelial growth factor and angiopoietins in focal cerebral ischemia

A growing body of evidence indicates that vascular growth factors and their receptors are activated after stroke, and these factors may contribute to ischemic cell damage and to angiogenesis during recovery from stroke. In this review, we focus on recent evidence for roles of vascular endothelial growth factor (VEGF) and angiopoietin 1 (Ang 1) in blood-brain barrier (BBB) leakage and angiogenesis after focal cerebral ischemia.     

小鼠局灶性脑缺血后乙酰肝素酶的表达

目的检测乙酰肝素酶（Hpa）在实验小鼠局灶性脑缺血后的表达,探讨其表达时间和表达位置变化的规律及其意义。方法用结扎大脑中动脉皮质支的方法制作小鼠局灶性脑缺血模型;碰用实时荧光定啦PCR方法检测缺血后Hpa、血管内皮生长因子（VEGF）和血管生成素2（Ang-2）基因的表达;应用免疫荧光双染（Hpa／CD105、Hpa／GFAP、Hpa／BrdU）的方法进一步观察Hpa蛋白表达的情况。结果实验组小鼠脑缺血后,与假手术组比较,HpamRNA于缺血后3d开始在缺血区的表达明显增高（P〈0．05）,14d达到相对高峰（与1、3、7d和假手术组比较,P〈0．05—0．01）。VEGFmRNA和Ang-2mRNA在脑缺血后3d的表达亦明鼹增高（与假手术组比较,P〈0．01）,其中VEGF的表达水平持续增高,而Ang-2则随后降低：免疫荧光双染显示,Hpa在脑缺血后7d时主要表达于新生的微血管,14d时主要与星形胶质细胞共表达：结论Hpa表达时间和表达位置的变化提示,Hpa参与了脑缺血后血管新生和组织修复的过程,推测Hpa可能通过促进VEGF的表达以及星形胶质细胞的增生而发挥其作用．     

血管内皮生长因子在脑缺血中的作用

血管内皮生长因子(vascular endothelial growth factor,VEGF)是一种重要的调节多种内皮功能的血管生长因子.脑缺血后,VEGF不仪能促进血管内皮细胞增殖和迁移,参与血管生成,增加血管通透性,而且在神经保护和神经发生等方面也起着重要作用.文章就VEGF在缺血性脑损伤中的作用进行了综述.     

血管内皮生长因子与中枢神经系统疾病

血管内皮生长因子具有增加血管通透性 ,促进内皮细胞增殖和血管生成以及保护神经组织等重要作用 ,与多种中枢神经系统疾病 ,如脑缺血、脑出血和脑肿瘤的发生发展密切相关 ,其基因治疗有望为相关疾病的治疗提供新的途径和方法。     

Induction of focal angiogenesis through adenoviral vector mediated vascular endothelial cell growth factor gene transfer in the mature mouse brain

Vascular endothelial growth factor (VEGF) is a potent endothelial cell mitogen and morphogen, which stimulates angiogenesis in a wide variety of tissues and lesions in vivo. In this study, we applied adenoviral vector delivered human VEGF165 cDNA to develop focal non-tumor angiogenesis in the mature mouse brain. Seventy-two adult CD-1 mice underwent Ad h VEGF, Ad lacZ, and saline injection for up to fourweeks. An adenoviral suspension containing 1 x 10(9) particles was injected stereotactically into the right hemisphere of the brain. The results showed that VEGF expression was increased in the Ad h VEGF transduced mice compared to Ad lacZ or saline injected mice ( P < 0.05). VEGF-positive cells were mainly located in the injection hemisphere of Ad h VEGF transduced mice. Quantitative vessel counting showed that microvessels in the Ad h VEGF transduced mice increased following 2 weeks of Ad h VEGF gene transfer compared to the other two groups (Ad h VEGF:241 +/- 19 vs. Ad lacZ :148 +/- 17 and Saline:150 +/- 14 vessels/mm2, P < 0.05). Morphology showed typical angiogenic changes. PCNA-positive staining confirmed these microvessels were actively proliferating. Our study demonstrates that Ad h VEGF-induced VEGF hyper-stimulation causes focal angiogenesis in the mature mouse brain. This novel method of inducing in vivo brain focal angiogenesis provides an opportunity to study the molecular mechanisms independent of the confounding effects of upstream inciting stimuli such as ischemia or tumor.     

缺血后大鼠脑内神经血管单元病理损害的研究

目的观察慢性缺血后大鼠脑内神经血管单元的病理损害。方法将30只Wistar大鼠随机分为假手术组5只和缺血组25只。缺血组大鼠分别在缺血3、7、14 d、1、3个月时间段,各取5只灌注取脑,采用HE染色观察大鼠神经细胞的病理改变;免疫组织化学半定量检测胶质纤维酸性蛋白(GFAP)、血管内皮生长因子(VEGF)和层黏连蛋白(Laminin)的含量,观察其动态变化规律。结果缺血早期神经元皱缩、肿胀,后期嗜酸性变和坏死。星形胶质细胞早期肿胀、断裂,随着缺血时间的延长胶质细胞开始增生,形成瘢痕组织,同时伴有血管新生。与假手术组比较,缺血组大鼠5个时间段GFAP表达进行性增加;缺血3 d VEGF表达开始增加,7、14 d增加明显(P0.05),1、3个月VEGF表达虽有减少但仍高于假手术组(P0.05)。缺血3 d Laminin明显减少,7 d减少更明显,14 d、1、3个月表达逐渐增加(P0.05)。结论慢性脑缺血后在不同时间段,神经元、GFAP、VEGF、Laminin呈规律变化。脑部缺血后不仅是神经元的变化,还有胶质细胞、血管内皮细胞及基底膜的变化。