Microglial-macrophage synthesis of tumor necrosis factor after focal cerebral ischemia in mice is strain dependent.

Commonly used inbred mouse strains display substantial differences in sensitivity to focal cerebral ischemia. Such differences can often be ascribed to differences in vascular anatomy. The authors investigated whether a contributing factor could be strain-related differences in cellular synthesis of the pleiotropic and potential neurotoxic cytokine tumor necrosis factor (TNF) in the border zone of and within the focal cerebral infarct. In all mouse strains investigated they found that TNF was synthesized by infarct and periinfarct infiltrating Mac-1 immunopositive microglia-macrophages. BALB/c mice, which developed the largest infarcts, contained significantly fewer TNF-producing microglia-macrophages compared with SJL and C57BL/6 mice at both 12 and 24 hours after permanent occlusion of the distal part of the middle cerebral artery. SJL mice developed larger infarcts than C57BL/6 mice, whereas the number of TNF-producing microglia-macrophages per infarct volume unit was comparable. Western blotting data confirmed the increased TNF levels in SJL mice compared with BALB/c and C57BL/6 mice. Furthermore, mice with 12-hour postischemic survival consistently contained two-to threefold more TNF-producing microglia-macrophages than mice with 24-hour survival. The data show that the magnitude of the cellular TNF response to cerebral ischemia is strain dependent, while the time-profile and the cellular sources of TNF are similar irrespective of genetic background. Furthermore, the lack of correlation between infarct size and cellular TNF response suggests that the functionally important TNF is produced in the very early phase (minutes to a few hours) after induction of ischemia, just as it raises the possibility that different mouse strains display different sensitivities to TNF.     

Leukocyte-endothelium interactions during permanent focal cerebral ischemia in mice.

The contribution of leukocyte infiltration to brain damage after permanent focal cerebral ischemia and the underlying molecular mechanisms are still unclear. Therefore, the aim of this study was to establish a mouse model for the visualization of leukocytes in the cerebral microcirculation in vivo and to investigate leukocyte-endothelial interaction (LEI) after permanent middle cerebral artery occlusion (MCAO). Sham-operated 129/Sv mice showed physiologic LEI in pial venules as observed by intravital fluorescent microscopy. Permanent focal cerebral ischemia induced a significant increase of LEI predominantly in pial venules. The number of rolling and adherent leukocytes reached 36.5 +/- 13.2/100 microm x min and 22.5 +/- 7.9/100 microm x min, respectively at 120 minutes after MCAO (P = 0.016 vs. control). Of note, rolling and adherent leukocytes were also observed in arterioles of ischemic animals (7.3 +/- 3.0/100 microm x min rolling and 3.0 +/- 3.6/100 microm x min adherent). Capillary density was not different between groups. These results demonstrate that leukocytes accumulate in the brain not only after transient but also after permanent focal cerebral ischemia and may therefore contribute to brain damage after stroke without reperfusion.     

Tumor necrosis factor alpha expression produces increased blood-brain barrier permeability following temporary focal cerebral ischemia in mice.

Alteration of blood-brain barrier (BBB) function occurs in both permanent and temporary cerebral ischemia. Studies in vivo and in vitro have shown that tumor necrosis factor-alpha (TNFalpha) is involved in changes of BBB permeability. However, the relationship between TNFalpha expression and BBB disruption during reperfusion is unclear. The aim of this study is to find the cell source of TNFalpha and to determine the relationship between TNFalpha expression and BBB disruption following temporary focal cerebral ischemia in mice. Adult CD-1 mice received 1 h middle cerebral artery occlusion (MCAO) followed by 2 h, 6 h, 12 h, 24 h, and 48 h of reperfusion. MCAO was achieved using an intraluminal suture technique and reperfusion was performed by the suture withdrawal. Neutralizing monoclonal anti-mouse TNFalpha antibody was administrated intraventricularly immediately after reperfusion. TNFalpha expression was determined by double labeling immunohistochemistry. BBB permeability was determined by albumin immunostaining. TNFalpha immunoreactivity (IR) was observed in the ipsilateral hemisphere from 1 h MCAO with 2 h reperfusion. TNFalpha positive cells included neurons, astrocytes, and ependymal cells. BBB disruption was detected beginning at 6 h reperfusion but was not present at 2 h of reperfusion. The areas of BBB disruption were significantly enlarged at 12 h reperfusion and plateaued at 24 h to 48 h reperfusion. BBB disruptions were significantly attenuated in the anti-TNFalpha antibody treated mice (p<0.05). Our results demonstrate that TNFalpha IR existed in neurons, astrocytes, and ependymal cells during reperfusion. TNFalpha IR following temporary focal cerebral ischemia precedes increased BBB permeability. Treatment with TNFalpha antibody reduces BBB disruption, suggesting TNFalpha may be an important mediator in altering BBB permeability during reperfusion.     

Expression of tumor necrosis factor-alpha and intercellular adhesion molecule-1 after focal cerebral ischemia in interleukin-1beta converting enzyme deficient mice.

Interleukin-1beta (IL-1beta) is expressed after cerebral ischemia and blocking its action reduces subsequent ischemic brain injury. However, the mechanisms by which IL-1beta affects ischemic brain are not understood. To investigate the role of IL- 1beta in regulation of tumor necrosis factor-alpha (TNF-alpha) and intercellular adhesion molecule-1 (ICAM-1) during focal cerebral ischemia, the authors studied mutant mice deficient in the IL-1 converting enzyme (ICE) gene (ICE knockout [KO] mice). Ninety-four adult male ICE KO and wild-type mice underwent 3, 6, 12, and 24 hours of permanent middle cerebral artery occlusion using the suture method. Expression of TNF-alpha and ICAM-1 protein in ischemic brain was examined using immunohistochemistry and Western blot analysis. Neither ICE KO nor wild-type mice had significant differences in CBF and body temperature measurements during the ischemic procedure. TNF-alpha expression increased in the ipsilateral hemisphere after 3 hours of occlusion, peaked at 12 hours and decreased at 24 hours of ischemia in both ICE KO and wild-type mice. ICAM-1 immunohistochemistry showed that the number of ICAM-1-positive vessels in the ischemic hemisphere was reduced in ICE KO mice (P < .05). Western blot analysis showed that ICAM-1 protein expression was significantly attenuated in the ipsilateral hemisphere in the ICE KO mice, which paralleled the immunohistochemistry results. The authors' results indicate that TNF-alpha expression is increased in both ICE KO and wild-type mice suggesting that TNF-alpha expression is not related to or upregulated by IL-1beta . ICAM-1 expression is significantly reduced in the ICE KO mice suggesting that IL-1beta plays an important role in the upregulation of adhesion molecules during focal cerebral ischemia.     

A role for interferon-gamma in focal cerebral ischemia in mice

The pro-inflammatory cytokine interferon-gamma (IFNgamma) has traditionally been associated with inflammatory CNS disease and more recently with ischemia-induced pathology. Using a murine model of focal cerebral ischemia, we found no evidence for induction of IFNgamma mRNA after permanent middle cerebral artery occlusion. In addition, we found that mice deficient in IFNgamma or IFNgamma receptors developed neocortical infarcts similar in size to those in wild type. In contrast, MBP promoter-IFNgamma-transgenic mice consistently developed significantly larger infarcts than non-transgenic mice. Because IFNgamma is a potent activator of microglia-macrophages, we investigated the involvement of microglial-macrophage-derived TNF in the larger infarcts. Numbers of TNF mRNA-expressing microglia-macrophages and levels of TNF mRNA and TNF in IFNgamma-transgenic and non-transgenic mice were similar. Furthermore, the ischemic brain damage in IFN-gamma-transgenic mice was unaffected by recombinant soluble TNF receptor I. Taken together, the data argues against a role for IFNgamma in cerebral ischemia under normal conditions. However, when present, IFNgamma significantly exacerbates ischemia-induced brain damage by mechanisms that appear to be independent of TNF or synergistic neurotoxic interactions of IFNgamma and TNF Irrespective of the mechanism(s) involved, this enhancing effect of IFNgamma on ischemia-induced neurotoxicity may need to be considered in diseases where immune IFNgamma is involved, such as multiple sclerosis.     

Production of platelet-activating factor during focal cerebral ischemia and reperfusion in the rat

Platelet-activating factor (PAF) is a phospholipid mediator implicated in a diverse range of pathological processes. Beneficial effects of PAF antagonists have been shown in various models of central nervous system ischemia. In this study, we evaluated the production of PAF during focal cerebral ischemia and reperfusion in the rat. Ischemia was induced by occlusion of the middle cerebral artery with a thread. Quantification of PAF was performed with the radioimmunoassay technique. PAF was detected in the brain under normal conditions. Tissue PAF level in the ischemic cerebral hemisphere significantly decreased by prolonged ischemia (P<.05). Conversely, the decreased tissue PAF level during ischemia was significantly increased again by reperfusion (P<.05), but was still low compared with the control. This study indicates that the production of PAF in the brain tissue decreased by prolonged ischemia, and suggests the role of PAF in the reperfusion phase rather than during ischemia in the pathophysiology of ischemic brain injury.     

A potential role for erythropoietin in focal permanent cerebral ischemia in mice.

The present study describes, for the first time, a temporal and spatial cellular expression of erythropoietin (Epo) and Epo receptor (Epo-R) with the evolution of a cerebral infarct after focal permanent ischemia in mice. In addition to a basal expression of Epo in neurons and astrocytes, a postischemic Epo expression has been localized specifically to endothelial cells (1 day), microglia/macrophage-like cells (3 days), and reactive astrocytes (7 days after occlusion). Under these conditions, the Epo-R expression always precedes that of Epo for each cell type. These results support the hypothesis that there is a continuous formation of Epo, with its corresponding receptor, during the active evolution of a focal cerebral infarct and that the Epo/Epo-R system might be implicated in the processes of neuroprotection and restructuring (such as angiogenesis and gliosis) after ischemia. To support this hypothesis, a significant reduction in infarct volume (47%; P < 0.0002) was found in mice treated with recombinant Epo 24 hours before induction of cerebral ischemia. Based on the above, we propose that the Epo/Epo-R system is an endogenous mechanism that protects the brain against damages consequent to a reduction in blood flow, a mechanism that can be amplified by the intracerebroventricular application of exogenous recombinant Epo.     

Cognitive deficits after focal cerebral ischemia in mice

BACKGROUND AND PURPOSE: The interpretation of cognitive data in many experimental stroke studies is problematic because middle cerebral artery occlusion (MCAO) is associated with sensorimotor alterations that may become confounding factors in cognitive testing. The purpose of the current study was to determine if it is possible to measure MCAO-induced cognitive deficits by using short durations of ischemia that do not result in alterations in sensorimotor behavior in mice. METHODS: Male C57/Bl6 mice were subjected to 60 or 90 minutes of intraluminal MCAO or sham surgery. In the first cohort of animals (n=12/group), locomotor activity, balance, and coordination were evaluated 2 weeks after surgery. In a second cohort of animals (n=10/group), the effects of 60 minutes of MCAO on subsequent learning and memory were assessed with a step-down passive avoidance task beginning 1 week after surgery. In a third cohort of animals (n=8 to 10/group), training in a passive avoidance task was completed before 60 minutes of MCAO, then retention of the task was assessed 1 week after surgery. In all animals, infarction size was determined after 14 days of reperfusion with use of cresyl violet staining and quantitative image analysis. RESULTS: There was no significant difference in infarction volume in the cerebral cortex or caudoputamen after 60 versus 90 minutes of MCAO. However, there was a significant increase in latency to move 1 body length in the 90-minute MCAO group compared with the 60-minute MCAO and sham groups. In 2 additional cohorts of animals, 60-minute MCAO was associated with a deficit in the acquisition and retention of a passive avoidance task regardless of whether the task training occurred before or after MCAO. CONCLUSIONS: Long-term cognitive deficits can be induced in mice by using a short duration of MCAO (60 minutes) that does not result in concomitant sensorimotor deficits.     

Nuclear translocation of apoptosis-inducing factor after focal cerebral ischemia.

Signaling cascades associated with apoptosis contribute to cell death after focal cerebral ischemia. Cytochrome c release from mitochondria and the subsequent activation of caspases 9 and 3 are critical steps. Recently, a novel mitochondrial protein, apoptosis-inducing factor (AIF), has been implicated in caspase-independent programmed cell death following its translocation to the nucleus. We, therefore, addressed the question whether AIF also plays a role in cell death after focal cerebral ischemia. We detected AIF relocation from mitochondria to nucleus in primary cultured rat neurons 4 and 8 hours after 4 hours of oxygen/glucose deprivation. In ischemic mouse brain, AIF was detected within the nucleus 1 hour after reperfusion after 45 minutes occlusion of the middle cerebral artery. AIF translocation preceded cell death, occurred before or at the time when cytochrome c was released from mitochondria, and was evident within cells showing apoptosis-related DNA fragmentation. From these findings, we infer that AIF may be involved in neuronal cell death after focal cerebral ischemia and that caspase-independent signaling pathways downstream of mitochondria may play a role in apoptotic-like cell death after experimental stroke.     

Double-tracer autoradiographic study of protein synthesis and glucose consumption in rats with focal cerebral ischemia.

A double-tracer autoradiographic method for simultaneous measurement of regional glucose utilization (rCMRglc) and regional protein synthesis (PS) in consecutive brain sections is described and applied to study the metabolism of the ischemic penumbra 2 h after occlusion of the middle cerebral artery (MCAO) in rats. In halothane anesthesia, the left middle cerebral artery was permanently occluded. Two hours after MCAO an i.v. bolus injection of 14C-deoxyglucose and 3H-leucine was given and circulated for 45 min. Two sets of brain sections were processed for quantitative autoradiography. Neighboring brain sections exposed an X-ray film (3H-insensitive), and a 3H-sensitive for determination of rCMRglc and PS, respectively. Sections for PS determination were washed in trichloroacetic acid (TCA) prior to film exposure in order to remove 14C-deoxyglucose and unincorporated 3H-leucine. Regional rates of PS and glucose utilization were measured by densitometric image analysis. Normal rates of metabolism were defined as mean +/- 2 SD of values in the non-ischemic cortex. The volumes of ischemic cortex displaying normal rates of PS and glucose utilization, respectively, were measured. The cortical volume with normal PS was significantly less than that of normal rCMRglc: 142 (127-147) mm3 vs. 203 (184-206) mm3. Treatment with the glutamate antagonists MK-801 (1 mg kg-1) and NBQX (30 mg kg-1 x 2) did not significantly change this, although MK-801 tended to reduce the size of the metabolic penumbra calculated as the difference between ischemic cortex with reduced PS and ischemic cortex with reduced rCMRglc.     

急性脑梗死患者血清肿瘤坏死因子及循环内皮细胞含量变化的对比研究

目的　研究急性脑梗死 (ACI)患者血清肿瘤坏死因子 (TNF)及循环内皮细胞 (CEC)含量的变化 ,探讨 TNF与 CEC的关系及其临床意义。方法　采用放射免疫分析法检测 6 0例 ACI患者血清 TNF- α和 CEC的含量 ,并与 2 0例健康人作对照。结果　 (1)脑梗死患者急性期血清 TNF- α和 CEC含量明显高于恢复期 (P<0 .0 1)。恢复期血清 TNF- α及 CEC则高于正常水平 (P<0 .0 1)。 (2 )脑梗死急性期血清 TNF- α和 CEC升高的程度与梗死灶大小密切相关 (P<0 .0 1)。 (3)急性期血清 TNF- α与 CEC呈正相关 (r=0 .6 9,P<0 .0 1)。结论　 ACI患者血清TNF- α及 CEC含量升高 ,提示 TNF- α及血管内皮细胞的损伤共同参与脑梗死的发生发展过程。保护血管内皮细胞 ,降低 TNF- α的水平 ,对于缺血性脑血管病的防治将具有重要意义。     

Effects of nimodipine on acute focal cerebral ischemia

Nimodipine is a calcium slow channel blocker with several pharmacologic properties suggesting the potential to favorably modify outcome in focal cerebral ischemia. Thirty adult cats underwent unilateral middle cerebral artery (MCA) occlusion for 4 hours. Seventeen cats were treated with an ipsilateral intracarotid infusion of nimodipine (1 microgram kg-1 min -1) beginning 15 minutes before MCA occlusion and continuing throughout the occlusion period. Eight nimodipine treated cats maintaining MAP greater than 90 mmHg were assigned to a Higher Pressure Nimodipine (HPN) group. The remaining nine treated cats with MAP less than 90 mmHg were assigned to the Lower Pressure Nimodipine (LPN) group. Thirteen cats were untreated, receiving an isovolumetric amount of vehicle through the ipsilateral carotid artery. Local cerebral blood flow (ICBF) was continuously monitored using thermal diffusion probes. The brains, assessed for colloidal carbon perfusion, fluorescein and Evans blue staining, electroencephalographic activity (EEG), and histological changes, revealed no significant differences by any of these methods between the HPN and control animals with the exceptions of: HPN treated cats exhibited a preservation of EEG activity at 15 minutes post-occlusion compared to the untreated cats, and Post-ischemic surface colloidal carbon perfusion was better preserved in the treated cats than in the untreated cats. Mild hypotension, as demonstrated by the LPN group, negated these two positive effects. Prior to MCA occlusion, ICBF was bilaterally significantly increased after nimodipine infusion in the HPN group as compared to vehicle infusion. Intra-arterially infused nimodipine did not reduce infarct size.     

Delayed pentobarbital therapy of acute focal cerebral ischemia

The efficacy of pentobarbital in the delayed treatment of acute cerebral ischemia was investigated in cats. Cerebral ischemia was produced by left middle cerebral artery (LMCA) ligation. Ten cats received 50 mg/kg of pentobarbital prior to ligation; a second group of 10 cats received the same dose of pentobarbital 2 hrs after ligation, and the control group of 7 cats received no pentobarbital. Brains were removed after spontaneous or induced death and the volume infarction was determined histologically. It was found that the volume of brain infarction in the group receiving pentobarbital 2 hrs after ligation was significantly less than that of the control group, which received no pentobarbital; but the volume of infarction in the former group was significantly greater than that found in the experimental group, which received pentobarbital prior to ligation. However, the mortality after LMCA ligation was higher in the 2 experimental groups, which received pentobarbital therapy, than in the control group, which did not receive pentobarbital. An hypothesis was advanced, which speculated that secondary adrenal insufficiency and altered cardiovascular function accounted for the increased mortality after pentobarbital treatment of patients with ischemic stroke.     

Evolution of brain infarction after transient focal cerebral ischemia in mice.

The evolution of brain infarction after transient focal cerebral ischemia was studied in mice using multiparametric imaging techniques. One-hour focal cerebral ischemia was induced by occluding the middle cerebral artery using the intraluminal filament technique. Cerebral protein synthesis (CPS) and the regional tissue content of adenosine triphosphate (ATP) were measured after recirculation times from 0 hours to 3 days. The observed changes were correlated with the expression of the mRNAs of hsp-70, c-fos, and junB, as well as the distribution of DNA double-strand breaks, visualized by TUNEL. At the end of 1 hour of ischemia, protein synthesis was suppressed in a larger tissue volume than ATP in accordance with the biochemical differentiation between core and penumbra. Hsp70 mRNA was selectively expressed in the cortical penumbra, whereas c-fos and junB mRNAs were increased both in the lateral part of the penumbra and in the ipsilateral cingulate cortex with normal metabolism. During reperfusion after withdrawal of the intraluminal filament, suppression of CPS persisted except in the most peripheral parts of the middle cerebral artery territory, in which it recovered between 6 hours and 3 days. ATP, in contrast, returned to normal levels within 1 hour but secondarily deteriorated from 3 hours on until, between 1 and 3 days, the ATP-depleted area merged with that of suppressed protein synthesis leading to delayed brain infarction. Hsp70 mRNA, but not c-fos and junB, was strongly expressed during reperfusion, peaking at 3 hours after reperfusion. TUNEL-positive cells were detected from 3 hours on, mainly in areas with secondary ATP depletion. These results stress the importance of an early recovery of CPS for the prevention of ischemic injury and suggest that TUNEL is an unspecific response of delayed brain infarction.     

Treatment of acute focal cerebral ischemia with prostacyclin

The object of this investigation was to study the effects of prostacyclin (PGI2) upon the evolution of acute focal cerebral ischemia in the cat. Twenty-five fasted adult cats, lightly anesthetized with nitrous oxide, underwent right middle cerebral artery (MCA) occlusion. Eleven cats received an intracarotid infusion of PGI2 in buffered saline pH 10.5 (100 ng/kg/min at 0.01 ml/kg/min), and 11 cats received intracarotid buffered saline pH 10.5 (0.01 ml/kg/min) without therapeutic agents. Treatment with PGI2 was started upon MCA occlusion and continued for 6 hours. Thirty minutes prior to perfusion, the animals were given fluorescein and Evans blue by intravenous injection. The cats were perfused-fixed in vivo with carbon and buffered formalin 6 hours after MCA occlusion. Another 3 cats received tritium labeled intracarotid PGI2, and peripheral venous samples were collected and assayed for PGI2 plasma levels. Mean arterial pressure was stable in PGI2 treated animals during 6 hours of MCA occlusion, while untreated cats had significant progressive hypertension during that period. The rCBF (measured by the intracarotid 133Xe method) decreased markedly in all animals immediately upon MCA occlusion. However, untreated animals had a significant progressive improvement in rCBF during the occlusion period, while PGI2 treated animals had no such improvement. Quantitative EEG changes, gross edema, areas of fluorescein extravasation, patterns of carbon perfusion, and infarct size were not significantly different in the two groups. While most untreated animals had marked Evans blue extravasation after 6 hours of MCA occlusion, most PGI2 treated animals had no such extravasation, indicating some protection of the blood-brain barrier in these animals.     

可重复性小鼠局灶性脑缺血/再灌注模型的探讨

目的介绍一种标准的小鼠局灶性脑缺血/再灌注模型的制作方法,并观察不同脑缺血/再灌注时间脑梗死体积和脑水肿的变化。方法用腔内线栓法制作脑缺血/再灌注动物模型,用TTC染色法进行脑大体观察,用甲酚紫染色法观察脑切片梗死灶,用脑血流激光多普勒监测脑血流的变化,用ImageJ软件计算脑梗死体积和脑水肿。结果当线栓封闭大脑中动脉时,脑血流就会急剧下降至最低水平,拔出线栓后脑血流迅速上升至缺血前水平。脑缺血后,脑片上呈现明显的梗死灶,脑梗死体积和脑水肿的大小较恒定。脑缺血90min再灌注24h组梗死体积、脑水肿体积、脑水肿百分数及神经功能缺损程度均显著大于脑缺血30min再灌注24h组(P<0.001)。脑缺血30min/再灌注72h脑水肿非常明显(72.6±4.3)mm3,再灌注7d时脑水肿开始减退,仅为(50.9±4.1)mm3,再灌注30d时脑容积出现萎缩,脑水肿呈负值(-20.1±1.8)mm3。结论该小鼠局灶性脑缺血/再灌注模型具有重复性好、容易操作的优点。脑缺血30min就可造成不可逆性脑损害,脑水肿在再灌注72h即达到高峰。     

A new model of transient focal cerebral ischemia for inducing selective neuronal necrosis

Brief cerebral ischemia leads to selective neuronal necrosis (SNN), which is characterized by neuronal death with sparing of glial and vascular elements of the central nervous system. Understanding the pathophysiology of SNN may help elucidating the mechanisms and consequences of neuronal injury in humans following brief ischemia. Contrary to the presence of reproducible models of transient global ischemia, animal models of transient focal ischemia producing SNN are scarce and have important limitations such as causing ischemia in a vast area and inducing additional insults. In this study, we developed a practical mouse model of SNN without these limitations, by compressing the distal middle cerebral artery (MCA) with a blunted micropipette for 15 min. The success of compression was evaluated by monitoring the regional cerebral blood flow, and conventional histopathology and immunolabeling of the brain sections. Seven/fourteen days after ischemia, intracisternally administered propidium iodide labeled numerous necrotic cells in the frontoparietal cortex, which were mostly NeuN-positive, but were not immunolabeled with astrocytic markers (GFAP and S100), and showed neuronal morphology with hematoxylin–eosin staining, indicating that the model successfully induced ischemic injury limited to neurons. The model could become an important tool for investigating the long-term effects of brief ischemic events like transient ischemic attacks and could offer convenient reversible distal MCA occlusion for studies using intravital microscopy.     

Transient focal cerebral ischemia induces sensorimotor deficits in mice

Rodents have been extensively used for experimental stroke research with rat and gerbil the preferred species. With the advent of transgenesis and gene targeting the number of mutant mouse strains is rapidly increasing. Thus, mouse models of stroke will be of great importance in the analysis of genetic factors affecting stroke. Demonstrating long-term functional recovery is of paramount importance for the pharmacological evaluation of putative stroke therapies. In the present paper we induce mild focal cerebral ischemia by tandem occlusion of the right middle cerebral artery (MCA), via craniotomy, together with the common carotid artery for 45 min in C57BL/6 strain of mice. The effects of ischemia were evaluated acutely by MRI and long-term (> 3 weeks) sensorimotor functional deficits were analyzed using a number of behavioral paradigms including the rotorod, wire hang, horizontal surface approach, eye-closure reflex, and T-maze tests. Although the induced brain damage is mild we show that it leads to clearly detectable and significant sensorimotor defects associated with fine motor coordination, balance, and postural and sensory reflexes. We conclude that the applied behavioral tests will be useful in the analysis of stroke in mutant mice.