Adenovirus-mediated gene transfer of glial cell line-derived neurotrophic factor prevents ischemic brain injury after transient middle cerebral artery occlusion in rats.

To examine a possible protective effect of exogenous glial cell line-derived neurotrophic factor (GDNF) gene expression against ischemic brain injury, a replication-defective adenoviral vector containing GDNF gene (Ad-GDNF) was directly injected into the cerebral cortex at 1 day before 90 minutes of transient middle cerebral artery occlusion (MCAO) in rats. 2,3,5-Triphenyltetrazolium chloride staining showed that infarct volume of the Ad-GDNF-injected group at 24 hours after the transient MCAO was significantly smaller than that of vehicle- or Ad-LacZ-treated group. Enzyme-linked immunosorbent assay (ELISA) for immunoreactive GDNF demonstrated that GDNF gene products in the Ad-GDNF-injected group were higher than those of vehicle-treated group at 24 hours after transient MCAO. Immunoreactive GDNF staining was obviously detected in the cortex around the needle track just before or 24 hours after MCAO in the Ad-GDNF group, whereas no or slight GDNF staining was detected in the vehicle group. The numbers of TUNEL, immunoreactive caspase-3, and cytochrome c-positive neurons induced in the ipsilateral cerebral cortex at 24 hours after transient MCAO were markedly reduced by the Ad-GDNF group. These results suggest that the successful exogenous GDNF gene transfer ameliorates ischemic brain injury after transient MCAO in association with the reduction of apoptotic signals.     

Reduction of ischemic stroke in rat brain by alpha melanocyte stimulating hormone

Anti-inflammatory therapy has provided hope for a new effective treatment of brain ischemic stroke. In this study, adult male Wistar rats subjected to right middle cerebral artery occlusion (MCAO) for 60 min were allocated to treatment of the anti-inflammatory compound alpha melanocyte stimulating hormone (alpha-MSH) or saline. Magnetic resonance imaging (MRI) and histology were used to evaluate the effects of alpha-MSH. MRI volumetry was performed to measure infarct size, and MRI measurements of the apparent diffusion coefficient (ADC) were performed to evaluate changes in the extra/intracellular volume ratio. Triphenyltetrazolium chloride (TTC) staining was used as a reference method to measure infarct sizes. The ADC value of the infarct area decreased significantly two days after MCAO in both groups. Simultaneously the infarct volume determined from the ADC map decreased in the alpha-MSH treated group compared to the control group. Five days after MCAO, ADC returned to baseline levels in both groups. The infarct volume in the alpha-MSH group was smaller compared to the saline treated group as demonstrated both by MRI and TTC staining. This study showed that the extra/intracellular ratio (reflected by ADC) following focal brain ischemic stroke could be affected by alpha-MSH. Secondly, we showed that the infarct volume was reduced by alpha-MSH. The volumetric dimensions of the infarct areas measured by MRI were comparable to those measured by histology.     

Kallikrein基因转导对脑缺血再灌注后局部血流灌注恢复的作用

目的 探讨Kallikrein基因对脑缺血再灌注后梗死灶周围血管增生与局部脑血流灌注恢复的作用.方法 建立大鼠脑缺血再灌注模型,术后将90只大鼠按照随机数字表法分为3组.每组30只,分别是空白对照组、注射生理盐水、注射pAdCMV-人组织激肽释放酶(HTK)组.各组大鼠又分为治疗后12 h、24 h及72 h组,每组各10只.治疗前后行大鼠神经功能缺损评分.TTC染色方法测定脑梗死面积的变化,用免疫组化检测外源性HTK的表达以及局部血管内皮生长因子(VEGF)的表达,并通过14C-iodoantipyrine微示踪技术检测局部脑血流灌注(rCBF)情况.结果 与其他两组相比,pAdCMV-HTK组大鼠脑梗死面积在治疗后24h已有明显减小,72h后这种变化更明显,差异有统计学意义(P<0.05);在治疗后24 h,pAdCMV-HTK组大鼠神经功能缺损评分明显低于生理盐水组及空白对照组,治疗后72h差异更明显,差异有统计学意义(P<0.05).vEGF阳性细胞主要分布于脑梗死灶周边皮质与部分白质;pAdCMV-HTK组VEGF表达在治疗后12h、24h、72h均明显高于生理盐水组及空白对照组,差异有统计学意义(P<0.05).各组缺血再灌注后脑梗死灶周围白质与皮质rCBF均较对侧稍减少:pAdCMV-HTK组治疗后12h,梗死灶周围白质与皮质rCBF较空白对照组与生理盐水组有增高.但不明显,差异无统计学意义(P>0.05),而在治疗24h、72 h后rCBF则明显增高,差异有统计学意义(P<0.05).结论 在脑缺血再灌注后,Kallikrein基因转导可增加梗死灶周围脑组织的血管增生,改善rCBF,减小梗死面积,从而达到保护缺血神经细胞功能的作用.     

阿托伐他汀对大鼠脑缺血再灌注后梗死灶周围中性粒细胞浸润和核转录因子-κB表达水平的影响

目的 观察阿托伐他汀对大鼠脑缺血再灌注后梗死灶周围中性粒细胞浸润以及核转录因子-κB表达水平的影响.方法 采用常规尼龙线栓法制备SD大鼠脑缺血再灌注模型,并将大鼠随机分为假手术组、大脑中动脉阻断再灌注(Middle cerebral artery occlusion/reperfusion,MCAO/R)(对照)组和M...     

NR_1反义抑制剂对局灶性脑缺血作用的初步研究

目的　探讨NR1反义寡核苷酸对局灶性脑缺血的治疗作用。方法　于大鼠大脑中动脉闭塞后2小时、2 4小时分别经侧脑室注射磷酸缓冲液 (PBS)、错义寡核苷酸 (MSODN)及反义寡核苷酸 (ASODN) ,然后在不同时间点进行神经功能缺损评分 ,术后第 5天进行Nissl染色、TTC染色及梗死体积比测定。结果　各组局灶性脑缺血的神经功能缺损评分无显著性差异 ;反义寡核苷酸治疗组的梗死体积比显著低于单纯缺血组 ;反义寡核苷酸治疗组海马各区神经元损伤轻 ,神经元丢失相对较少。结论　局灶性脑缺血后侧脑室注入NR1反义寡核苷酸 ,可以减轻缺血脑组织病理学损害 ,具有脑保护作用。     

单次9小时高压氧超早期治疗对大鼠脑梗死体积的影响

目的 本研究主要观察高压氧（HBO）单次9 h超早期治疗对永久性大脑中动脉阻塞（MCAO）大鼠脑梗死体积的影响。方法 制作SD大鼠永久性MCAO模型,随机分为对照组、HBO组,HBO组大鼠于模型制备成功后3 h予单次9 h HBO治疗,压力0.2 MPa。模型成功后13 h、5 d,分别将大鼠脑组织进行2,3,5苯四氮唑（TTC）染色测定梗死体积,免疫组织化学染色测定脑组织中血管内皮生长因子（VEGF）的表达情况。结果 （1）13 h时,两组大鼠脑梗死体积相差不大（P >0.05）;5 d时,对照组大鼠脑梗死体积较13 h时增大（P <0.05）,而HBO组变化不大（P >0.05）,组间比较,HBO组较对照组脑梗死体积缩小（P <0.05）。（2）13 h时,对照组和HBO组VEGF均有表达,两组间差异无统计学意义（P >0.05）;5 d时,对照组VEGF表达较13 h时明显减少（P <0.01）,而HBO组VEGF表达明显高于13 h,而且显著高于对照组5 d水平（P <0.01）。结论 单次9 h HBO超早期治疗可缩小大鼠脑梗死体积,其机制可能与HBO提高内源性VEGF表达有关。     

Pretreatment with intravenous FGF-13 reduces infarct volume and ameliorates neurological deficits following focal cerebral ischemia in rats

Fibroblast growth factor-13 (FGF-13), novel member of FGF family has recently been molecularly cloned as a result of high throughput sequencing of a ovarian cancer cell, hippocampal, and kidney cDNA libraries. The human gene encodes for a protein with a molecular weight of 22 kDa that is most homologous to FGF-8 (70% similarity). In the current study, we tested the effects of intravenously administered FGF-13 in a model of permanent focal cerebral ischemia in Sprague–Dawley rats. FGF-13 or the vehicle was administered systematically via the tail vein 30 min prior, and 30 min and 24 h after the occlusion of the left middle cerebral artery (MCAo). Animals were weighed and evaluated behaviorally prior to and at 24 and 48 h after MCAo. The volume of cerebral infarct and swelling were determined using an image analysis system (BioQuant) and cresyl violet stained sequential sections from the forebrain region. Histopathology was evaluated to compare the therapeutic effects. We found a 63% reduction in infarct volume in FGF-13- vs. vehicle-treated animals (infarct volume was 21.9±3.8% in vehicle- and 8.1±1.6% in FGF-13-treated rats, p=0.0016) and a moderate inhibition of brain swelling by FGF-13. The reduction in infarct volume and brain swelling were associated with improvement of clinical deficits in FGF-13 treated animals (p<0.001). Histopathological examination determined that nervous tissue was better preserved in FGF-13 treated rats than those of controls. These data show that pretreatment with intravenous FGF-13 reduces infarct size and ameliorates neurological deficits following permanent focal cerebral ischemia in rats.     

Enlarged infarct volume and loss of BDNF mRNA induction following brain ischemia in mice lacking FGF-2

FGF-2, a potent multifunctional and neurotrophic growth factor, is widely expressed in the brain and upregulated in cerebral ischemia. Previous studies have shown that intraventricularly or systemically administered FGF-2 reduces the size of cerebral infarcts. Whether endogenous FGF-2 is beneficial for the outcome of cerebral ischemia has not been investigated. We have used mice with a null mutation of the fgf2 gene to explore the relevance of endogenous FGF-2 in brain ischemia. Focal cerebral ischemia was produced by occlusion of the middle cerebral artery (MCAO). We found a 75% increase in infarct volume in fgf2 knock-out mice versus wild type littermates (P < 0.05). This difference in the extent of ischemic damage was observed after 24 h, and correlated with decreased viability in fgf2 mutant mice following MCA occlusion. Increased infarct volume in fgf2 null mice was associated with a loss of induction in hippocampal BDNF and trkB mRNA expression. These findings indicate that signaling through trkB may contribute to ameliorating brain damage following ischemia and that bdnf and trkB may be target genes of FGF-2. Together, our data provide the first evidence that endogenous FGF-2 is important in coping with ischemic brain damage suggesting fgf2 as one crucial target gene for new therapeutic strategies in brain ischemia.     

高压氧预处理减少局灶性脑缺血后泛素化蛋白聚集

目的探讨泛素-蛋白酶体系统在重复高压氧（HBO）预处理导致的脑缺血耐受中所起的作用。方法采用大脑中动脉阻闭（MCAO）制备大鼠局灶性脑缺血模型,将33只SD大鼠随机分为假手术组（Sham）组、MCAO组和HBO组,分别观察各组大鼠脑梗死灶的大小和神经功能学评分,并用免疫组织化学染色检测再灌注2h、24h时相点大鼠脑组织CA1区异常泛素化蛋白聚集的变化。结果 HBO组脑梗死容积小于MCAO组,差异有统计学意义（P〈0.05）,其神经功能学评分也明显优于MCAO组（P〈0.05）。再灌注各时相点,HBO组泛素化蛋白聚集明显少于MCAO组（P〈0.05）。结论高压氧预处理所诱导的脑缺血耐受的机制可能与泛素化蛋白聚集降低有关。     

Effects of kallikrein gene transfer on penumbral microvascular proliferation and on regional cerebral blood flow following cerebral ischemia/reperfusion injury

BACKGROUND： Recent findings have demonstrated that the kallikrein-kinin system （KKS） participates in the pathological process of cerebral ischemia/reperfusion injury. Kallikrein gene transfer exhibits neural protective effects following cerebral infarction. OBJECTIVE： To observe the effects of kallikrein gene transfer on vascular proliferation in the peripheral infarct focus and on regional cerebral blood flow （rCBF） following cerebral ischemia/reperfusion injury. DESIGN, TIME AND SETTING： The completely randomized, controlled experiment was performed at the Lin Baixin Laboratory Center, the Second Affiliated Hospital of Sun Yat-sun University between September 2007 and April 2008. MATERIALS： pUCI9-HTK plasmid was constructed and maintained in the Laboratory for Neurology, the Second Affiliated Hospital of Sun Yat-sen University, China. Mouse anti-human kallikrein 1 monoclonal antibody was purchased from R＆D Systems, USA. METHODS Ninety healthy, male, Sprague Dawley rats were used. Middle cerebral artery occlusion （MCAO） was established in all rats to induce cerebral ischemia/reperfusion injury. Following MCAO establishment, all rats were randomly divided into three groups （n = 30）： blank control, saline, and pAdCMV-HTK. The saline and pAdCMV-HTK groups were stereotactically micro-injected with 5μL of physiological saline or with pAdCMV-HTK [multiplicity of infection （MOI） = 20], respectively, into the ischemic penumbra. In the blank control group, only sham injection was performed. MAIN OUTCOME MEASURES： At 12, 24, and 72 hours after treatment, cerebral infarction volume was measured by 2, 3, 5-triphenyltetrazolium chloride （TTC） staining. Exogenous HTK expression, as well as regional vascular endothelial growth factor （VEGF） expression, was detected by immunohistochemistry. rCBF was examined by 14C-iodoantipyrine micro tracing. In addition, neurological severity score （NSS） was performed. Higher scores indicated more severe neurological deficits. RESULTS： NSS res     

电针预处理对脑缺血再灌注后SOD_2的表达影响

目的观察电针预处理对脑缺血再灌注后锰超氧化物歧化酶表达的影响。方法成年雄性C57小鼠随机分为假手术组(sham)、电针预处理组(EA)、大脑中动脉栓塞组(MCAO)、电针加大脑中动脉栓塞组(EA+MCAO),采用MCAO法诱导小鼠局灶性脑缺血再灌注模型。再灌2 h应用Western blot以及免疫荧光组织化学染色技术检测SOD2表达,再灌24 h评估神经行为学、测量脑梗死容积和神经细胞凋亡。结果脑缺血再灌注2 h,SOD2表达显著降低,而电针预处理可上调SOD2的表达,增加SOD2在神经元的免疫荧光强度。同时电针预处理可改善缺血再灌注后的神经功能障碍,减轻脑梗死容积率,减少末端脱氧核苷酸转移酶介导的生物素脱氧尿嘧啶核苷酸缺口末端标记法(TUNEL)阳性细胞数目。结论电针预处理可上调脑缺血再灌注后SOD2表达,可能参与其诱导的脑保护作用。     

Qualitative and quantitative analysis of the progressive cerebral damage after middle cerebral artery occlusion in mice

The middle cerebral artery occlusion (MCAO) in mice induces a focal cerebral ischaemia at the level of the tempo-parietal cortex. Histological staining and immunohistochemical markers were used to characterize the temporal progression of the cerebral infarct: both qualitative and quantitative analyses were performed at different days after the MCAO. At 3 days after MCAO, an extensive necrosis of the cerebral parenchyma was accompanied by extravasation and by massive oedema. After 7 days, GFAP marker showed a gliotic reaction with alteration of the astrocytes membrane permeability (S100 marker). Positivity for acid phosphatase staining indicated the presence of macrophages. At Day 14 and 21 following MCAO, the histological profile was essentially similar. Interestingly, at Day 7, 14 and 21, a previously unreported gliosis was observed in the subthalamic area. Quantitative analysis showed a significantly larger infarct volume at Day 3 (7.88 ± 1.95 mm³ ± S.E.M.) compared to Day 7 (4.28 ± 0.47 mm³ ± S.E.M.). At Day 14 and Day 21 the infarct volumes were further decreased to 2.00 ± 0.52 and 1.43 ± 0.39 mm³ ± S.E.M., respectively. These results suggest that it is important to consider the time of evaluation of cerebral ischaemia-induced cerebral infarct, especially in studies which aim to evaluate the neuroprotective effect of putative therapeutic agents.     

血管内皮生长因子基因对大鼠缺血脑组织的保护作用

目的　探讨血管内皮生长因子基因对大鼠缺血脑组织的保护作用 ,为临床治疗脑梗死提供实验依据。方法　用线拴法制成Wistar大鼠大脑中动脉永久性闭塞模型 ,将VEGF1 6 5真核表达质粒 (pUCCAGGS/hVEGF1 6 5)经颅骨注入到缺血区。术后 7d断头取脑 ,2 %红四氮唑 (TTC)染色测梗死体积、HE染色观察组织坏死情况、免疫组织化学检测VEGF1 6 5基因的表达。结果　治疗组VEGF表达高 ,脑组织坏死明显减轻 ,脑梗死体积明显缩小 (P <0 .0 1 )。结论　在质粒载体介导下 ,VEGF基因可转化到缺血脑组织中并表达VEGF ,进而保护神经细胞 ,治疗脑梗死     

Mild hypothermia enhances the neuroprotective effects of FK506 and expands its therapeutic window following transient focal ischemia in rats

FK506 (tacrolimus), an immunosuppressant, reportedly reduces ischemic brain injury following transient middle cerebral artery occlusion (MCAO) in rats. The authors previously reported that the therapeutic window of FK506 in this model is more than 1 h, but less than 2 h. The aim of the present study is to determine whether mild hypothermia (35 degrees C) enhances the neuroprotective effects of FK506 and expands its therapeutic window. Sprague-Dawley rats were subjected to 2 h MCAO followed by 24 h reperfusion. Animals were randomly divided into four groups: (I) vehicle-treated normothermic group; (II) FK506-treated normothermic group; (III) vehicle-treated hypothermic group; (IV) FK506-treated hypothermic group. Animals received a single injection of FK506 (0.3 mg/kg) or vehicle intravenously at 2 h after ischemic induction. During ischemia, temporal muscle and rectal temperatures were maintained at 37 degrees C in the normothermic animals and at 35 degrees C in the hypothermic animals. Infarct volumes and neurological performance were evaluated at 24 h after reperfusion. The combination of FK506 and mild hypothermia significantly reduced infarct volume (cortex, -61%; striatum, -31%) and edema volume (cortex, -57%; striatum, -41%), while mild hypothermia or FK506 alone failed to improve ischemic brain damage. Furthermore, this combination also provided for the best functional outcome. These results demonstrate that the combination of FK506 and mild hypothermia significantly reduces ischemic brain damage following transient MCAO in rats, and expands the therapeutic window for FK506. This therapy may be a new approach for treatment of acute stroke.     

Reduced infarct volume and differential effects on glial cell activation after hyperbaric oxygen treatment in rat permanent focal cerebral ischaemia

Permanent middle cerebral artery occlusion (MCAO) causes neurodegeneration and a robust activation of glial cells primarily in sensorimotor brain regions of rats. It has been shown that hyperbaric oxygen (HBO) increases oxygen supply to ischaemic areas and reduces neuronal cell loss. The effects of HBO treatment on microgliosis and astrogliosis in permanent cerebral ischaemia have not been addressed so far, but might be critical for neurodegeneration and neuroprotection, respectively. Therefore, we used spontaneously hypertensive rats with permanent MCAO to investigate the time window to start HBO and to compare the effects of different HBO treatment frequencies on infarct volume and on differences with regard to microgliosis and astrogliosis. Seven days after MCAO the infarct volume was calculated from Nissl-stained brain sections by image analysis. HBO significantly decreased the infarct volume when used as early as 15, 90 or 180 min post-MCAO by 24%, 16% and 13%, respectively, in the single-treatment group. Repetitive HBO treatment (first HBO session 90 min after MCAO) was not effective. Microglial cells and astrocytes were detected by cytochemical fluorescent labelling and confocal laser scanning microscopy. In the single-treatment group we observed significantly higher astrocyte immunoreactivity but decreased microglial density in the peri-infarct region. These effects of HBO treatment on glial cells were not present in rats where HBO did not reduce the infarct volume (360 min after MCAO). Our data indicate that HBO-induced suppression of microgliosis and aggravated response of astrocytes might contribute to the reported beneficial effects of early HBO treatment in cerebral ischaemia.     

Effects of intravenous dimethyl sulfoxide on ischemia evolution in a rat permanent occlusion model.

Dimethyl sulfoxide (DMSO) has a variety of biological actions that suggest efficacy as a neuroprotectant. We (1) tested the neuroprotective potential of DMSO at different time windows on infarct size using 2,3,5-triphenyltetrazolium staining and (2) investigated the effects of DMSO on ischemia evolution using quantitative diffusion and perfusion imaging in a permanent middle cerebral artery occlusion (MCAO) model in rats. In experiment 1, DMSO treatment (1.5 g/kg intravenously over 3 h) reduced infarct volume 24 h after MCAO by 65% (P<0.00001) when initiated 20 h before MCAO, by 44% (P=0.0006) when initiated 1 h after MCAO, and by 17% (P=0.11) when started 2 h after MCAO. Significant infarct reduction was also observed after a 3-day survival in animals treated 1 h after MCAO (P=0.005). In experiment 2, treatment was initiated 1 h after MCAO and maps for cerebral blood flow (CBF) and apparent diffusion coefficient (ADC) were acquired before treatment and then every 30 mins up to 4 h. Cerebral blood flow characteristics and CBF-derived lesion volumes did not differ between treated and untreated animals, whereas the ADC-derived lesion volume essentially stopped progressing during DMSO treatment, resulting in a persistent diffusion/perfusion mismatch. This effect was mainly observed in the cortex. Our data suggest that DMSO represents an interesting candidate for acute stroke treatment.     

胰岛素对局灶性脑缺血再灌注损伤的作用

目的　观察胰岛素对脑缺血再灌注损伤的治疗作用。方法　制备易卒中型肾血管性高血压大鼠（ Ｒ Ｈ Ｒ Ｓ Ｐ） ,用线栓法复制大脑中动脉阻塞（ Ｍ Ｃ Ａ Ｏ） ,造成缺血６ ｈ 再灌注１８ ｈ ,术后立即及６ 小时后即时使用胰岛素,测定神经功能障碍评分及脑梗死体积的变化。结果　胰岛素可使神经功能障碍评分显著减低,梗死灶体积及其占全大脑体积比值,两半球体积差值显著减小。结论　胰岛素能减轻脑缺血再灌注损伤,早期用药效果更好。     

脑不对称性对大鼠局灶性脑缺血模型的梗死体积及行为功能的影响

目的 探讨不同时间点应用线栓法制作不同侧别大脑中动脉闭塞（middle c erebral a rtery o cclusion, MCAO）模型对大鼠神经功能和脑梗死体积的影响。 方法 参照Zea-Longa法制作大鼠局灶脑缺血模型,1.5 h后进行缺血再灌注（I/R）。36只SD大鼠随机 分为经左、右侧插线组,并对两组大鼠I/R后不同时间点（1、3、7 d）的神经功能缺损评分、平衡木试 验、水迷宫试验及脑梗死体积进行测定和比较。 结果 经左侧MCAO组大鼠的肢体运动平衡能力在I/R后1、3、7 d均显著低于右侧组,而记忆功能显 著高于右侧组,以I/R后7 d差异更明显。两组脑梗死体积在I/R后3 d时最大,7 d时最小;在I/R后1 d及 3 d时两组脑梗死体积无明显差异;而I/R后7 d时,左侧组梗死体积高于右侧组。 结论 栓塞左右侧对大鼠MCAO模型早期梗死体积影响不大,而后期左侧栓塞的梗死体积大于右侧。 并且左侧半球梗死引起的运动功能损害更重,右侧半球梗死引起的记忆功能缺损更严重。提示大鼠 左右脑半球可能存在结构和功能的不对称,从而影响局灶性脑缺血的结局。     

Administration of transforming growth factor-alpha reduces infarct volume after transient focal cerebral ischemia in the rat.

Growth factors promote cell growth and survival and protect the brain from developing injury after ischemia. In this article, the authors examined whether transforming growth factor-alpha (TGF-alpha) was protective in transient focal ischemia and whether alteration of cerebral circulation was involved. Rats received intraventricular TGF-alpha (50 ng, either split into 2 doses given 30 minutes before and 30 minutes after middle cerebral artery occlusion (MCAO), or 1 dose given 30 minutes after MCAO) or vehicle. Rats were subjected to 1-hour intraluminal MCAO and cerebral blood flow was recorded continuously by laser-Doppler flowmetry. Infarct volume was measured 1 and 4 days later. The effects of TGF-alpha on arterial tone were assessed in isolated rabbit basilar and common carotid arteries. Transforming growth factor-alpha before and after ischemia reduced infarct volume by 70% at 1 day and 50% at 4 days. Transforming growth factor-alpha given only after ischemia also did reduce infarct volume by 70% at 1 day and 80% at 4 days. The protective effect was more marked in cortex than in striatum. Transforming growth factor-alpha did not change cortical microvascular perfusion and did not modify arterial passive tone nor agonist-induced active tone. It can be concluded that TGF-alpha reduces infarct volume, even when the factor is exclusively administered at reperfusion, and that this effect is not mediated by changes in microvascular perfusion or cerebral arteries. It is therefore suggested that TGF-alpha has a protective effect against neuronal cell death after transient focal ischemia.