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Middle Cerebral Artery Occlusion (middle + cerebral_artery_occlusion)
Kinds of Middle Cerebral Artery Occlusion Terms modified by Middle Cerebral Artery Occlusion Selected AbstractsMODULATION OF SIGNAL TRANSDUCERS AND ACTIVATORS OF TRANSCRIPTION (STAT) FACTOR PATHWAYS DURING FOCAL CEREBRAL ISCHAEMIA: A GENE EXPRESSION ARRAY STUDY IN RAT HIPPOCAMPUS AFTER MIDDLE CEREBRAL ARTERY OCCLUSIONCLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 11 2007Sheng-Li Sun SUMMARY 1Signal transducers and activators of transcription (STAT) factors are a family of transcription factors that mediate intracellular signalling initiated at cytokine cell surface receptors and transmitted to the nucleus. In the present study, we determined the global changes in STAT gene expression in the hippocampus of rats after focal cerebral ischaemia and reperfusion using microarray analysis. 2The present study used middle cerebral artery occlusion (MCAO) to induce ischaemia and reperfusion in Sprague-Dawley rats. Using superarray Q series Janus tyrosine kinases (Jak)/STAT signalling pathway gene array, a total of 96 genes was screened in adult male rat hippocampus after transient focal cerebral ischaemia. 3The results showed that 23 genes were upregulated at least twofold by ischaemia treatment and that 12 genes were downregulated at least threefold by ischaemia treatment compared with controls. 4After confirmation by quantitative real-time polymerase chain reaction, the data suggest that the gene expression of STAT2, 5a, 5b, 6 and suppressor of cytokine signalling (SOCS) 4 was increased by ischaemia, probably due to a compensatory response of the brain, which may play a protective role in damaged brain tissue. 5The results of the present study provide evidence on global changes in STAT gene expression in the hippocampus of rats after focal cerebral ischaemia and reperfusion, in which STAT2, 5a, 5b, 6 and SOCS4 were confirmed to be significantly modulated during focal cerebral ischaemia. [source] Association of Pretreatment ASPECTS Scores with tPA-Induced Arterial Recanalization in Acute Middle Cerebral Artery OcclusionJOURNAL OF NEUROIMAGING, Issue 1 2008Georgios Tsivgoulis MD ABSTRACT BACKGROUND AND PURPOSE The Alberta Stroke Program Early CT-Score (ASPECTS) assesses early ischemic changes within the middle cerebral artery (MCA) and predicts poor outcome and increased risk for thrombolysis-related symptomatic ICH. We evaluated the potential relationship between pretreatment ASPECTS and tPA-induced recanalization in patients with MCA occlusions. SUBJECTS & METHODS Consecutive patients with acute ischemic stroke due to MCA occlusion were treated with standard IV-tPA and assessed with transcranial Doppler (TCD) for arterial recanalization. Early recanalization was determined with previously validated Thrombolysis in Brain Ischemia (TIBI) flow-grading system at 120 minutes after tPA-bolus. All pretreatment CT-scans were prospectively scored by trained investigators blinded to TCD findings. Functional outcome at 3 months was evaluated using the modified Rankin Scale (mRS). RESULTS IV-tPA was administered in 192 patients (mean age 68 ± 14 years, median NIHSS-score 17). Patients with complete recanalization (n= 51) had higher median pretreatment ASPECTS (10, interquartile range 2) than patients with incomplete or absent recanalization (n= 141; median ASPECTS 9, interquartile range 3, P= .034 Mann-Whitney U-test). An ASPECTS ,6 was documented in 4% and 17% of patients with present and absent recanalization, respectively (P= .019). Pretreatment ASPECTS was associated with complete recanalization (OR per 1-point increase: 1.54; 95% CI 1.06,2.22, P= .023) after adjustment for baseline characteristics, risk factors, NIHSS-score, pretreatment TIBI grades and site of arterial occlusion on baseline TCD. Complete recanalization (OR: 33.97, 95% CI 5.95,185.99, P < .001) and higher ASPECTS (OR per 1-point increase: 1.91; 95% CI 1.17,3.14, P= .010) were independent predictors of good functional outcome (mRS 0,2). CONCLUSIONS Higher pretreatment ASPECT-scores are associated with a greater chance of complete recanalization and favorable long-term outcome in tPA-treated patients with acute MCA occlusion. [source] Overexpression of APP provides neuroprotection in the absence of functional benefit following middle cerebral artery occlusion in ratsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 7 2007Jared Clarke Abstract Cerebral ischaemia leads to a transient accumulation of ,-amyloid precursor protein (APP) and ,-amyloid (A,) peptides adjacent to the ischaemic lesion. There is conflicting evidence that APP/A, fragments may either enhance neuronal plasticity or be neurotoxic. The aim of the current study was to assess the effect of overexpression of human APP in rats on functional recovery following cerebral ischaemia. Adult APP-overexpressing (hAPP695 Tg) rats subjected to transient middle cerebral artery occlusion (MCAO) had significantly smaller infarct volumes than non-transgenic littermates, yet did not perform better on a series of sensorimotor or learning tests during a 6-month follow-up period. In fact, transgenic animals were found to be significantly more impaired in both the beam-walking and Morris water maze tests following MCAO. Immunohistochemistry showed human A,-positive staining in the cortex and hippocampus of APP transgenic rats. The present data suggest that while overexpression of APP in rats may provide some histological neuroprotection in the event of cerebral ischaemia, this does not translate into significant functional recovery. [source] Calpain cleavage of collapsin response mediator proteins in ischemic mouse brainEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2007Susan X. Jiang Abstract Collapsin response mediator proteins (CRMPs) are important brain-specific proteins with distinct functions in modulating growth cone collapse and axonal guidance during brain development. Our previous studies have shown that calpain cleaves CRMP3 in the adult mouse brain during cerebral ischemia [S.T. Hou et al. (2006) J. Neurosci., 26, 2241,2249]. Here, the expression of all CRMP family members (1,5) was examined in mouse brains that were subjected to middle cerebral artery occlusion. Among the five CRMPs, the expressions of CRMP1, CRMP3 and CRMP5 were the most abundant in the cerebral cortex and all CRMPs were targeted for cleavage by ischemia-activated calpain. Sub-cellular fractionation analysis showed that cleavage of CRMPs by calpain occurred not only in the cytoplasm but also in the synaptosomes isolated from ischemic brains. Moreover, synaptosomal CRMPs appeared to be at least one-fold more sensitive to cleavage compared with those isolated from the cytosolic fraction in an in-vitro experiment, suggesting that synaptosomal CRMPs are critical targets during cerebral ischemia-induced neuronal injury. Finally, the expression of all CRMPs was colocalized with TUNEL-positive neurons in the ischemic mouse brain, which further supports the notion that CRMPs may play an important role in neuronal death following cerebral ischemia. Collectively, these studies demonstrated that CRMPs are targets of calpains during cerebral ischemia and they also highlighted an important potential role that CRMPs may play in modulating ischemic neuronal death. [source] Dietary phytoestrogens improve stroke outcome after transient focal cerebral ischemia in ratsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2006María C. Burguete Abstract As phytoestrogens are postulated as being neuroprotectants, we assessed the hypothesis that dietary isoflavone-type phytoestrogens are neuroprotective against ischemic stroke. Transient focal cerebral ischemia (90 min) was induced by middle cerebral artery occlusion (MCAO) following the intraluminal thread technique, both in rats fed with soy-based diet and in rats fed with isoflavone-free diet. Cerebro-cortical laser-Doppler flow (cortical perfusion, CP), arterial blood pressure, core temperature, PaO2, PaCO2, pH and glycemia were measured before, during and after MCAO. Neurological examination and infarct volume measurements were carried out 3 days after the ischemic insult. Dietary isoflavones (both glycosides and aglycones) were measured by high-performance liquide chromatography. Neither pre-ischemic, intra-ischemic nor post-ischemic CP values were significantly different between the soy-based diet and the isoflavone-free diet groups. Animals fed with the soy-based diet showed an infarct volume of 122 ± 20.2 mm3 (19 ± 3.3% of the whole ipsilateral hemisphere volume). In animals fed with the isoflavone-free diet the mean infarct volume was significantly higher, 191 ± 26.7 mm3 (28 ± 4.1%, P < 0.05). Neurological examination revealed significantly higher impairment in the isoflavone-free diet group compared with the soy-based diet group (3.3 ± 0.5 vs. 1.9 ± 0.5, P < 0.05). These results demonstrate that dietary isoflavones improve stroke outcome after transient focal cerebral ischemia in such a way that a higher dietary isoflavone content results in a lower infarct volume and a better neurological status. [source] N -methyl- d -aspartate receptor-mediated increase of neurogenesis in adult rat dentate gyrus following strokeEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 1 2001Andreas Arvidsson Abstract Neurogenesis in the adult rat dentate gyrus was studied following focal ischemic insults produced by middle cerebral artery occlusion (MCAO). Animals were subjected to either 30 min of MCAO, which causes damage confined to the striatum, or 2 h of MCAO, which leads to both striatal and cortical infarction. When compared to sham-operated rats, MCAO-rats showed a marked increase of the number of cells double-labelled for 5-bromo-2,-deoxyuridine-5,-monophosphate (BrdU; injected during 4,6 days postischemia) and neuronal-specific antigen (NeuN; a marker of postmitotic neurons) in the ipsilateral dentate granule cell layer and subgranular zone at 5 weeks following the 2 h insult. Only a modest and variable increase of BrdU-labelled cells was found after 30 min of MCAO. The enhanced neurogenesis was not dependent on cell death in the hippocampus, and its magnitude was not correlated to the degree of cortical damage. Systemic administration of the N -methyl- d -aspartate (NMDA) receptor blocker dizocilpine maleate (MK-801) completely suppressed the elevated neurogenesis following 2 h of MCAO. Our findings indicate that stroke leads to increased neurogenesis in the adult rat dentate gyrus through glutamatergic mechanisms acting on NMDA receptors. This modulatory effect may be mediated through changes in the levels of several growth factors, which occur after stroke, and could influence various regulatory steps of neurogenesis. [source] Candesartan pretreatment is cerebroprotective in a rat model of endothelin-1-induced middle cerebral artery occlusionEXPERIMENTAL PHYSIOLOGY, Issue 8 2009Adam P. Mecca Endogenous levels of angiotensin II (Ang II) are increased in the cortex and hypothalamus following stroke, and Ang II type 1 receptor blockers (ARBs) have been shown to attenuate the deleterious effects in animal stroke models using middle cerebral artery (MCA) intraluminal occlusion procedures. However, the endothelin-1 (ET-1)-induced middle cerebral artery occlusion (MCAO) model of cerebral ischaemia is thought to more closely mimic the temporal events of an embolic stroke. This method provides rapid occlusion of the MCA and a gradual reperfusion that lasts for 16,22 h. The aim of the present study was to evaluate whether systemic administration of an ARB prior to ET-1-induced MCAO would provide cerebroprotection during this model of ischaemic stroke. Injection of 3 ,l of 80 ,m ET-1 adjacent to the MCA resulted in complete occlusion of the vessel that resolved over a period of 30,40 min. Following ET-1-induced MCAO, rats had significant neurological impairment, as well as an infarct that consisted of 30% of the ipsilateral grey matter. Systemic pretreatment with 0.2 mg kg,1 day,1 candesartan for 7 days attenuated both the infarct size and the neurological deficits caused by ET-1-induced MCAO without altering blood pressure. This study confirms the cerebroprotective properties of ARBs during ischaemic stroke and validates the ET-1-induced MCAO model for examination of the role of the brain renin,angiotensin system in ischaemic stroke. [source] Down-regulation of neurocan expression in reactive astrocytes promotes axonal regeneration and facilitates the neurorestorative effects of bone marrow stromal cells in the ischemic rat brainGLIA, Issue 16 2008Li Hong Shen Abstract The glial scar, a primarily astrocytic structure bordering the infarct tissue inhibits axonal regeneration after stroke. Neurocan, an axonal extension inhibitory molecule, is up-regulated in the scar region after stroke. Bone marrow stromal cells (BMSCs) reduce the thickness of glial scar wall and facilitate axonal remodeling in the ischemic boundary zone. To further clarify the role of BMSCs in axonal regeneration and its underlying mechanism, the current study focused on the effect of BMSCs on neurocan expression in the ischemic brain. Thirty-one adult male Wistar rats were subjected to 2 h of middle cerebral artery occlusion followed by an injection of 3 × 106 rat BMSCs (n = 16) or phosphate-buffered saline (n = 15) into the tail vein 24 h later. Animals were sacrificed at 8 days after stroke. Immunostaining analysis showed that reactive astrocytes were the primary source of neurocan, and BMSC-treated animals had significantly lower neurocan and higher growth associated protein 43 expression in the penumbral region compared with control rats, which was confirmed by Western blot analysis of the brain tissue. To further investigate the effects of BMSCs on astrocyte neurocan expression, single reactive astrocytes were collected from the ischemic boundary zone using laser capture microdissection. Neurocan gene expression was significantly down-regulated in rats receiving BMSC transplantation (n = 4/group). Primary cultured astrocytes showed similar alterations; BMSC coculture during reoxygenation abolished the up-regulation of neurocan gene in astrocytes undergoing oxygen-glucose deprivation (n = 3/group). Our data suggest that BMSCs promote axonal regeneration by reducing neurocan expression in peri-infarct astrocytes. © 2008 Wiley-Liss, Inc. [source] Inhomogeneous sodium accumulation in the ischemic core in rat focal cerebral ischemia by 23Na MRIJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 1 2009Victor E. Yushmanov PhD Abstract Purpose To test the hypotheses that (i) the regional heterogeneity of brain sodium concentration ([Na+]br) provides a parameter for ischemic progression not available from apparent diffusion coefficient (ADC) data, and (ii) [Na+]br increases more in ischemic cortex than in the caudate putamen (CP) with its lesser collateral circulation after middle cerebral artery occlusion in the rat. Materials and Methods 23Na twisted projection MRI was performed at 3 Tesla. [Na+]br was independently determined by flame photometry. The ischemic core was localized by ADC, by microtubule-associated protein-2 immunohistochemistry, and by changes in surface reflectivity. Results Within the ischemic core, the ADC ratio relative to the contralateral tissue was homogeneous (0.63 ± 0.07), whereas the rate of [Na+]br increase (slope) was heterogeneous (P < 0.005): 22 ± 4%/h in the sites of maximum slope versus 14 ± 1%/h elsewhere (here 100% is [Na+]br in the contralateral brain). Maximum slopes in the cortex were higher than in CP (P < 0.05). In the ischemic regions, there was no slope/ADC correlation between animals and within the same brain (P > 0.1). Maximum slope was located at the periphery of ischemic core in 8/10 animals. Conclusion Unlike ADC, 23Na MRI detected within-core ischemic lesion heterogeneity. J. Magn. Reson. Imaging 2009;30:18,24. © 2009 Wiley-Liss, Inc. [source] Subcortical lesions after transient thread occlusion in the rat: T2 -weighted magnetic resonance imaging findings without corresponding sensorimotor deficitsJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 4 2005Susanne Wegener MD Abstract Purpose To investigate infarct evolution and functional consequences of exclusive subcortical or cortico-subcortical strokes, transient middle cerebral artery occlusion (MCAO) was conducted in Wistar rats. Materials and Methods MCAO was induced in male Wistar rats (260,300 g) for 60 minutes. Lesion volumes and absolute T2 times on magnetic resonance imaging (MRI) were assessed 1 and 14 days after MCAO using a 4.7-T MRI animal scanner in conjunction with functional testing (adhesive tape removal, cylinder test, and ledged beam walking). Results Functional test scores were not distinguishable between sham-operated animals (N = 5) and those with exclusive caudoputaminal infarct (N = 8; group cp), but showed significant deficits in animals with cortico-subcortical infarction (N = 10; group cp+). The cp group had lower absolute T2 times and a more pronounced reduction in T2 lesion volume over time than the subcortical component in the cp+ group. There was no correlation of T2 lesion size or absolute T2 times and functional impairment in either group. Conclusion When judged from functional tests alone, subcortical ischemic lesions may not be diagnosed reliably. Furthermore, T2 -weighted (T2 -w) MRI does not well anticipate functional deficits in primarily striatal lesions. J. Magn. Reson. Imaging 2005;21:340,346. © 2005 Wiley-Liss, Inc. [source] Time evolution of cerebral perfusion and apparent diffusion coefficient measured by magnetic resonance imaging in a porcine stroke modelJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 2 2002Lisbeth Røhl MD Abstract Purpose To demonstrate the feasibility of sequential diffusion-weighted (DW) and perfusion-weighted (PW) magnetic resonance imaging (MRI) of a recently developed porcine stroke model and to evaluate the evolution of cerebral perfusion and the apparent diffusion coefficient (ADC) over time. Materials and Methods In five pigs, DW imaging (DWI) and PW imaging (PWI) was carried out for 7 hours after stroke onset, starting 1 hour after middle cerebral artery occlusion (MCAO). Results The DWI lesion volume increased significantly with time, and final DWI lesion volume correlated well with lesion area on histological sections (r = 0.910). T2 changes could be recognized 3 hours after stroke onset. At 1 hour the ADC ratio (ischemic lesion/contralateral side) was reduced to 0.81 in the caudate-putamen and to 0.87 in the cortex, and the cerebral blood flow ratio was reduced to 0.40 in the caudate-putamen and 0.51 in the cortex. Conclusion The level of flow reduction in the caudate-putamen and the cortex after 1 hour is in good correlation with human thresholds of irreversible and reversible ischemic damage, and accordingly, this model might be a model for mechanisms of infarct evolution and therapeutic intervention. J. Magn. Reson. Imaging 2002;15:123,129. © 2002 Wiley-Liss, Inc. [source] Neuroprotection by baicalein in ischemic brain injury involves PTEN/AKT pathwayJOURNAL OF NEUROCHEMISTRY, Issue 6 2010Chao Liu J. Neurochem. (2010) 112, 1500,1512. Abstract Recently more evidences support baicalein (Bai) is neuroprotective in models of ischemic stroke. This study was conducted to determine the molecular mechanisms involved in this effect. Either permanent or transient (2 h) middle cerebral artery occlusion (MCAO) was induced in rats in this study. Permanent MCAO led to larger infarct volumes in contrast to transient MCAO. Only in transient MCAO, Bai administration significantly reduced infarct size. Baicalein also markedly reduced apoptosis in the penumbra of transient MCAO rats. Additionally, oxygen and glucose deprivation (OGD) was used to mimic ischemic insult in primary cultured cortical neurons. A rapid increase in the intracellular reactive oxygen species level and nitrotyrosine formation induced by OGD was counteracted by Bai, which is parallel with attenuated cell injury. The reduction of phosphorylation Akt and glycogen synthase kinase-3, (GSK3,) induced by OGD was restored by Bai, which was associated with preserved levels of phosphorylation of PTEN, the phophatase that negatively regulates Akt. As a consequence, Bcl-2/Bcl-xL-associated death protein phosphorylation was increased and the protein level of Bcl-2 in motochondria was maintained, which subsequently antagonize cytochrome c released in cytosol. LY294002 blocked the increase in phospho-AKT evoked by Bai and abolished the associated protective effect. Together, these findings provide evidence that Bai protects neurons against ischemia injury and this neuroprotective effect involves PI3K/Akt and PTEN pathway. [source] Regulation of A2A adenosine receptor expression and functioning following permanent focal ischemia in rat brainJOURNAL OF NEUROCHEMISTRY, Issue 2 2008Maria L. Trincavelli Abstract Ischemia, through modulation of adenosine receptors (ARs), may influence adenosine-mediated-cellular responses. In the present study, we investigated the modulation of rat A2A receptor expression and functioning, in rat cerebral cortex and striatum, following in vivo focal ischemia (24 h). In cortex, middle cerebral artery occlusion did not induce any alterations in A2A receptor binding and functioning. On the contrary, in striatum, a significant decrease in A2A ligand affinity, associated with an increase in receptor density, were detected. In striatum, ischemia also induced a significant reduction both in G protein pool and in A2A receptor-G protein coupling. On the contrary, A2A receptor functional responsiveness, measured as stimulation of adenylyl cyclise, was not affected by ischemia, suggesting receptor up-regulation may represent a compensatory mechanism to maintain receptor functioning during cerebral damage. Immunohistochemical study showed that following 24 h middle cerebral artery occlusion, A2A ARs were definitely expressed both on neurons and activated microglia in ischemic striatum and cortex, but were not detected on astrocytes. In the non-ischemic hemisphere and in sham-operated rats A2A ARs were barely detected. Modifications of ARs may play a significant role in determining adenosine effects during ischemia and therefore should be taken into account when evaluating time-dependent protective effects of specific A2A active compounds. [source] Involvement of , protein kinase C in estrogen-induced neuroprotection against focal brain ischemia through G protein-coupled estrogen receptorJOURNAL OF NEUROCHEMISTRY, Issue 4 2005Shigeto Hayashi Abstract The neuroprotective effects of estrogen were studied in the ischemic model mice by 90 min transient unilateral middle cerebral artery occlusion (MCAO) followed by 22.5 h reperfusion. The total infarct size in C57BL/6 female mice after MCAO and reperfusion was significantly smaller than that in male mice. Intraperitoneal injection of estrogen after the start of reperfusion significantly reduced the infarct volume in the male mice. However, no significant gender difference was found in total infarct size in , protein kinase C (PKC)-knockout mice, suggesting that the neuroprotective effects of estrogen are due to the activation of a specific subtype of PKC, ,PKC, a neuron-specific PKC subtype, in the brain. We demonstrated that exogenous estrogen-induced neuroprotection was attenuated in ,PKC-knockout mice. Immunocytochemical study showed that ,PKC was translocated to nerve fiber-like structures when observed shortly after MCAO and reperfusion. We also visualized the rapid and reversible translocation of ,PKC-GFP (green fluorescent protein) by estrogen stimulation in living CHO-K1 cells. These results suggest that the activation of ,PKC through the G-protein-coupled estrogen receptors on the plasma membrane is involved in the estrogen-induced neuroprotection against focal brain ischemia. [source] Induction of Oxidative DNA Damage in the Peri-Infarct Region After Permanent Focal Cerebral IschemiaJOURNAL OF NEUROCHEMISTRY, Issue 4 2000Tetsuya Nagayama Abstract: To address the role of oxidative DNA damage in focal cerebral ischemia lacking reperfusion, we investigated DNA base and strand damage in a rat model of permanent middle cerebral artery occlusion (MCAO). Contents of 8-hydroxyl-2,-deoxyguanosine (8-OHdG) and apurinic/apyrimidinic abasic sites (AP sites), hallmarks of oxidative DNA damage, were quantitatively measured in nuclear DNA extracts from brains obtained 4-72 h after MCAO. DNA single- and double-strand breaks were detected on coronal brain sections using in situ DNA polymerase I-mediated biotin-dATP nick-translation (PANT) and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL), respectively. Levels of 8-OHdG and AP sites were markedly elevated 16-72 h following MCAO in the frontal cortex, representing the peri-infarct region, but levels did not significantly change within the ischemic core regions of the caudateputamen and parietal cortex. PANT- and TUNEL-positive cells began to be detectable 4-8 h following MCAO in the caudate-putamen and parietal cortex and reached maximal levels at 72 h. PANT- and TUNEL-positive cells were also detected 16-72 h after MCAO in the lateral frontal cortex within the infarct border, where many cells also showed colocalization of DNA single-strand breaks and DNA fragmentation. In contrast, levels of PANT-positive cells alone were transiently increased (16 h after MCAO) in the medial frontal cortex, an area distant from the infarct zone. These data suggest that within peri-infarct brain regions, oxidative injury to nuclear DNA in the form of base and strand damage may be a significant and contributory cause of secondary expansion of brain damage following permanent focal ischemia. [source] Stroke Injury in Rats Causes an Increase in Activin A Gene Expression Which is Unaffected by Oestradiol TreatmentJOURNAL OF NEUROENDOCRINOLOGY, Issue 2 2006M. Böttner Abstract Activins are members of the transforming growth factor-, superfamily that exert neurotrophic and neuroprotective effects on various neuronal populations. To determine the possible function of activin in stroke injury, we assessed which components of the activin signalling pathway were modulated in response to middle cerebral artery occlusion (MCAO). Furthermore, because oestradiol replacement protects against MCAO-induced cell death, we explored whether oestradiol replacement influences activin gene expression. Female Sprague-Dawley rats underwent permanent MCAO and the expression of activins and their corresponding receptors was determined by semiquantitative reverse transcriptase-polymerase chain reaction at 24 h after onset of ischaemia. We observed up-regulation of activin ,A and activin type I receptor A mRNA in response to injury. Dual-label immunocytochemistry followed by confocal z-stack analysis showed that the activin A expressing cells comprised neurones. Next, we monitored the time course of activin ,A mRNA expression in oestradiol- or vehicle-treated rats at 4, 8, 16 and 24 h after MCAO via in situ hybridisation. Starting at 4 h after injury, activin ,A mRNA was up-regulated in cortical and striatal areas in the ipsilateral hemisphere. Activin ,A mRNA levels in the cortex increased dramatically with time and were highest at 24 h after the insult, and oestradiol replacement did not influence this increase. [source] Antiapoptotic and antiautophagic effects of glial cell line-derived neurotrophic factor and hepatocyte growth factor after transient middle cerebral artery occlusion in ratsJOURNAL OF NEUROSCIENCE RESEARCH, Issue 10 2010Jingwei Shang Abstract Glial cell line-derived neurotrophic factor (GDNF) and hepatocyte growth factor (HGF) are strong neurotrophic factors, which function as antiapoptotic factors. However, the neuroprotective effect of GDNF and HGF in ameliorating ischemic brain injury via an antiautophagic effect has not been examined. Therefore, we investigated GDNF and HGF for changes of infarct size and antiapoptotic and antiautophagic effects after transient middle cerebral artery occlusion (tMCAO) in rats. For the estimation of ischemic brain injury, the infarct size was calculated at 24 hr after tMCAO by HE staining. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin in situ nick end labeling (TUNEL) was performed for evaluating the antiapoptotic effect. Western blot analysis of microtubule-associated protein 1 light chain 3 (LC3) and immunofluorescence analysis of LC3 and phosphorylated mTOR/Ser2448 (p-mTOR) were performed for evaluating the antiautophagic effect. GDNF and HGF significantly reduced infarct size after cerebral ischemia. The amounts of LC3-I plus LC3-II (relative to ,-tubulin) were significantly increased after tMCAO, and GDNF and HGF significantly decreased them. GDNF and HGF significantly increased p-mTOR-positive cells. GDNF and HGF significantly decreased the numbers of TUNEL-, LC3-, and LC3/TUNEL double-positive cells. LC3/TUNEL double-positive cells accounted for about 34.3% of LC3 plus TUNEL-positive cells. This study suggests that the protective effects of GDNF and HGF were greatly associated with not only the antiapoptotic but also the antiautophagic effects; maybe two types of cell death can occur in the same cell at the same time, and GDNF and HGF are capable of ameliorating these two pathways. © 2010 Wiley-Liss, Inc. [source] Protective role of COMP-Ang1 in ischemic rat brainJOURNAL OF NEUROSCIENCE RESEARCH, Issue 5 2010Hye Young Shin Abstract In cerebral ischemia, the induction of angiogenesis may represent a natural defense mechanism that enables the hypoxic brain to avoid progression into infarction. Angiopoietin-1 (Ang1) is known to produce non-leaky and stable blood vessel formation mainly by the Tie2 receptor. Therefore, we envisioned that the application of cartilage oligomeric matrix protein-Ang1 (COMP-Ang1), a soluble, stable, and potent form of Ang1, would promote angiogenesis and provide a protective effect following unilateral middle cerebral artery occlusion (MCAO) in rats. To this end, we employed a 2-hour-MCAO model, and treated rats with adenovirus encoding COMP-Ang1 (Ade-COMP-Ang1) or control virus encoding ,-gal (Ade-,-gal). Time course magnetic resonance images (MRIs) revealed significantly reduced infarct volume in the rats treated with Ade-COMP-Ang1 with an improvement of post-ischemic neurological deficits compared with rats treated with Ade-,-gal. Moreover, compared to the rats treated with Ade-,-gal, the rats treated with Ade-COMP-Ang1 showed an increase in blood vessels, especially in the border zone adjacent to the infarction, increased number of endogenous neuronal progenitor cells in the ischemic brain, and decreased number of TUNEL-positive cells. Taken together, COMP-Ang1 reduced infarct volume and consequently attenuated post-ischemic neurological deficits through enhanced angiogenesis and increased viable cell mass of neuronal cells. © 2009 Wiley-Liss, Inc. [source] Endogenous neurogenesis and neovascularization in the neocortex of the rat after focal cerebral ischemiaJOURNAL OF NEUROSCIENCE RESEARCH, Issue 2 2008Hye Young Shin Abstract The present study was designed to examine whether endogenous neurogenesis and neovascularization occur in the neocortex of the ischemic rat brain after unilateral middle cerebral artery occlusion (MCAO). Sprague-Dawley rats were divided into six groups (n = 29): one control group (n = 4) and five groups composed of animals sacrificed at increasing times post-MCAO (2 days and 1, 2, 4, and 8 weeks; n = 5 per group). To determine the presence of neurogenesis and neovascularization in the ischemic brain, nestin, Tuj1, NeuN, GFAP, Tie2, RECA, and 5-bromo-2,-deoxyuridine (BrdU) were analyzed immunohistochemically. In addition, nestin, GFAP, and Tie2 expression was determined by Western blotting. Triple-labeling of nestin, BrdU, and laminin was performed to visualize the interaction between endogenous neurogenesis and neovascularization. The number of BrdU- and nestin-colabeled cells increased markedly in the neocortex and border zone of the ischemic area up to 1 week after MCAO and decreased thereafter. Western blot analysis revealed that the expression of nestin, Tie-2, and GFAP was amplified in the ipsilateral hemisphere 2days after MCAO and peaked 1 week after MCAO, compared with that in the normal brain. After ischemic injury, nestin- and BrdU-colabeled cells were observed in the vicinity of the endothelial cells lining cerebral vessels in the ipsilateral neocortex of the ischemic brain. Endogenous neurogenesis and neovascularization were substantially activated and occurred in close proximity to one other in the ipsilateral neocortex of the ischemic rat brain. © 2007 Wiley-Liss, Inc. [source] Neurovascular and neuronal protection by E64d after focal cerebral ischemia in ratsJOURNAL OF NEUROSCIENCE RESEARCH, Issue 4 2006Tamiji Tsubokawa Abstract Calpains and cathepsins are two families of proteases that play an important role in ischemic cell death. In this study, we investigated the effect of E64d, a ,-calpain and cathepsin B inhibitor, in the prevention of neuronal and endothelial apoptotic cell death after focal cerebral ischemia in rats. Rats underwent 2 hr of transient focal ischemia from middle cerebral artery occlusion (MCAO) and were sacrificed 24 hr later. E64d (5 mg/ kg intraperitoneally) was administered 30 min before MCAO. Assessment included neurological function, infarction volume, brain water content, blood,brain barrier permeability, histology, and immunohistochemistry. The E64d-treated rats had significant brain protection against ischemic damage. We observed a reduction of infarction volume, brain edema, and improved neurological scores in E64d-treated rats compared with the nontreated control. Furthermore, there was a remarkable reduction in both proteases and caspase-3 activation and apoptotic changes in both neurons and endothelial cells in E64d-treated rats. These results suggest that E64d protects the brain against ischemic/reperfusion injury by attenuating neuronal and endothelial apoptosis. © 2006 Wiley-Liss, Inc. [source] Preconditioning with thrombin can be protective or worsen damage after endothelin-1-induced focal ischemia in ratsJOURNAL OF NEUROSCIENCE RESEARCH, Issue 3 2006Petra Henrich-Noack Abstract The serine protease thrombin has shown direct neuroprotective and neurotoxic effects on brain tissue in cerebral ischemia. Previous data suggested that thrombin-induced protection in vivo can be achieved by preconditioning rather than by acute treatment. In the current work, we used a model of mild ischemia to investigate the effects of preischemic intracerebral thrombin injection on neural damage. By intracerebral injection of endothelin-1 in freely moving animals, we achieved middle cerebral artery occlusion (MCAO), and 7 days postischemia we performed histological quantification of the infarct areas. Thrombin was injected as a preconditioning stimulus intracerebrally 7 days or 2 and 3 days before ischemia. For acute treatment, thrombin was injected 20 min before MCAO. Thrombin induced significant neuroprotection when given 7 days before endothelin-1-induced MCAO but was deleterious when given 2 and 3 days before the insult. The deleterious effect was not seen when thrombin was given acutely before ischemia. Our data demonstrate that preconditioning with thrombin can protect against damage or worsen ischemic damage. Its effect depended on the time interval between thrombin injection and insult. A low dose of thrombin did not induce a major deleterious effect in the acute phase of the infarct development after mild transient ischemia. © 2006 Wiley-Liss, Inc. [source] Spatiotemporal changes of apolipoprotein E immunoreactivity and apolipoprotein E mRNA expression after transient middle cerebral artery occlusion in rat brainJOURNAL OF NEUROSCIENCE RESEARCH, Issue 4 2003Hiroshi Kamada Abstract Apolipoprotein E (ApoE) is a constituent of lipoprotein and plays an important role in the maintenance of neural networks. However, spatiotemporal differences in ApoE expression and its long-term role in neural process after brain ischemia have not been studied. We investigated changes of ApoE immunoreactivity and ApoE mRNA expression both in the core and in the periischemic area at 1, 7, 21, or 56 days after 90 min of transient middle cerebral artery occlusion. Double stainings for ApoE plus NeuN or plus ED1 were performed in order to identify cell type of ApoE-positive stainings. The maximal increase of ApoE expression was observed at 7 days in the core and at 7 and 21 days in the periischemic area. In the core, ApoE plus NeuN double-positive cells increased at 1 and 7 days, without ApoE mRNA expression, whereas they increased in the periischemic area, with a peak at 21 days, with ApoE mRNA expression in glial cells but not in neurons. On the other hand, ApoE plus ED1 double-positive cells increased only in the core, with a peak in number at 7 and 21 days and marked ApoE mRNA expression in macrophages. The present study suggests that ApoE plays various important roles in different type of cells, reflecting spatiotemporal dissociation between degenerative and regenerative processes after brain ischemia, and that ApoE is profoundly involved in pathological conditions, such as brain ischemia. © 2003 Wiley-Liss, Inc. [source] Role of vascular endothelial growth factor in neuronal DNA damage and repair in rat brain following a transient cerebral ischemiaJOURNAL OF NEUROSCIENCE RESEARCH, Issue 2 2002Zeng-Jin Yang Abstract The antisense knockdown technique and confocal laser scanning microscopic analysis were used to elucidate vascular endothelial growth factor (VEGF) induction and its effect on DNA damage and repair in rat brain following a transient middle cerebral artery occlusion. Immunohistochemical study and in situ hybridization showed that the expression of VEGF and its mRNA was enhanced in the ischemic core and penumbra of ischemic brain. Western blot analysis further illustrated that VEGF induction was time-dependently changed in these areas. Double-staining analysis indicated that VEGF-positive staining existed in the neuron, but not in the glia, and it colocalized with excision repair cross-complementing group 6 (ERCC6) mRNA, a DNA repair factor. VEGF antisense oligodeoxynucleotide infusion reduced VEGF induction and resulted in an enlargement of infarct volume of the brain caused by ischemia. Moreover, it also increased the number of DNA damaged cells and lessened the induction of ERCC6 mRNA in ischemic brains. These results suggest that the induction of endogenous VEGF in ischemic neurons plays a neuroprotective role probably associated with the expression of ERCC6 mRNA. © 2002 Wiley-Liss, Inc. [source] Pretreatment with melatonin exerts anti-inflammatory effects against ischemia/reperfusion injury in a rat middle cerebral artery occlusion stroke modelJOURNAL OF PINEAL RESEARCH, Issue 2 2004Zhong Pei Abstract:, Inflammatory response following cerebral ischemia/reperfusion plays a key pathogenic role in ischemic cerebral damage. Nitric oxide (NO), cyclooxygenase-2 (COX-2) and myeloperoxidase (MPO) are important inflammatory mediators. Neuronal NO synthase (nNOS) is a major initial source of excessive NO during ischemia/reperfusion. Induction of COX-2 and infiltration of polymorphonuclear cells expressing MPO are critical factors in delayed inflammatory damage. Previously, we demonstrated that administration of melatonin before ischemia significantly reduced the infarct volume in a rat middle cerebral artery occlusion (MCAO) stroke model. In this study, we examined the effect of pretreatment with melatonin at 5 mg/kg on the immunoreactivity (ir) for nNOS, COX-2, MPO, and glial fibrillary acidic protein (GFAP) at 24, 48, and 72 hr after right-sided endovascular MCAO for 1 hr in adult male Sprague,Dawley rats. Melatonin did not affect the hemodynamic parameters. When compared with rats with sham MCAO, ischemia/reperfusion led to an ipsilateral increase in cells with positive ir for nNOS (similar at all times) and in ir-GFAP (similar at all times). Ischemia/reperfusion led to appearance of cells with positive ir for COX-2 (greatest at 24 hr with a tendency to increase again at 72 hr) or MPO (greatest at 24 hr). A single dose of melatonin significantly lessened the ipsilateral increase in cells with positive ir for nNOS, COX-2 or MPO, but did not influence the ipsilateral change in ir-GFAP. Our results suggest that melatonin treatment mediates neuroprotection against ischemia/reperfusion injury partly via inhibition of the consequential inflammatory response. [source] Stromelysin-1 (MMP-3) is critical for intracranial bleeding after t-PA treatment of stroke in miceJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 8 2007Y. SUZUKI Summary.,Background:,Tissue-type plasminogen activator (t-PA) is approved for treatment of ischemic stroke patients, but it may increase the risk of intracranial bleeding (ICB). Matrix metalloproteinases (MMPs), which can be activated through the plasminogen/plasmin system, may contribute to ICB after ischemic stroke. Objectives:,To explore the contribution of plasminogen, MMP-3 and MMP-9 to ICB associated with t-PA treatment after ischemic stroke. Methods:,Using a thrombotic middle cerebral artery occlusion (MCA-O) model, ICB was studied in mice with genetic deficiencies of plasminogen (Plg,/,), stromelysin-1 (MMP-3,/,), or gelatinase B (MMP-9,/,) and their corresponding wild-type (WT) littermates. The induction of MMP-3 and MMP-9 was also studied in C57BL/6 WT mice. Results:,ICB induced by t-PA (10 mg kg,1) was significantly less than WT in Plg,/, (P < 0.05) and MMP-3,/, (P < 0.05) but not in MMP-9,/, mice. Furthermore, administration of the broad-spectrum MMP inhibitor GM6001 after t-PA treatment reduced ICB significantly (P < 0.05) in MMP-3+/+ mice, but had no effect on MMP-3,/, mice. MMP-3 expression was significantly enhanced at the ischemic hemisphere; with placebo treatment, it was expressed only in neurons, whereas it was up-regulated in endothelial cells with t-PA treatment. Although MMP-9 expression was also significantly enhanced at the ischemic brain, the amount and the distribution were comparable in mice with and without t-PA treatment. Conclusions:,Our data with gene-deficient mice thus suggest that plasminogen and MMP-3 are relatively more important than MMP-9 for the increased ICB induced by t-PA treatment of ischemic stroke. [source] Vascular endothelial growth factor gene expression in middle cerebral artery occlusion in the ratACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 4 2005F. Lennmyr Background:, Focal cerebral ischemia induces up-regulation of angiogenic growth factors such as vascular endothelial growth factor (VEGF), which may have both beneficial and harmful effects to the ischemic brain. Vascular endothelial growth factor is up-regulated in models of brain ischemia, but the underlying mechanisms in vivo remain unclear. In the present report we have investigated the concomitant changes in VEGF and glyceraldehyde dehydrogenase (GAPDH) mRNA expression in a model of permanent and transient cerebral ischemia. Methods:, Male Sprague-Dawley rats were exposed to permanent or transient (2 h) middle cerebral artery occlusion (PMCAO, TMCAO). Brain samples were collected at survival times ranging from 6 h to 1 week, and the levels of VEGF164 and GAPDH mRNA were determined using reverse-transcriptase real-time polymerase chain reaction (RT-PCR). Results:, The VEGF mRNA levels decreased gradually over the observation period in a similar manner in both PMCAO and TMCAO. Maximum levels, seen at early observation time points, did not significantly deviate from sham controls. No statistically significant changes in GAPDH mRNA levels were observed, but there was a tendency towards a postischemic decrease with subsequent return to control levels over time. The VEGF/GAPDH ratio followed a pattern of decrease similar to VEGF mRNA alone. Conclusion:, The VEGF mRNA levels at 6 h after MCAO remain near baseline and thereafter decline, regardless of whether the occlusion is permanent or transient (2 h). The findings raise the question of other than transcriptional regulation of VEGF in cerebral ischemia. [source] Proton transfer ratio, lactate, and intracellular pH in acute cerebral ischemiaMAGNETIC RESONANCE IN MEDICINE, Issue 4 2007Kimmo T. Jokivarsi Abstract The amide proton transfer ratio (APTR) from the asymmetry of the Z -spectrum was determined in rat brain tissue during and after unilateral middle cerebral artery occlusion (MCAo). Cerebral lactate (Lac) as determined by 1H NMR spectroscopy, water diffusion, and T1, were quantified as well. Lac concentrations were used to estimate intracellular pH (pHi) in the brain during the MCA occlusion. A decrease in APTR during occlusion indicated acidification from 7.1 to 6.79 ± 0.19 (a drop by 0.3 ± 0.2 pH units), whereas pHi computed from Lac concentration was 6.3 ± 0.2 (a drop by 0.8 ± 0.2 pH units). Despite the disagreement between the two methods in terms of the size of the change in the absolute pHi during ischemia, ,APTR and pHi (and Lac concentration) displayed a strong correlation during the MCAo. Diffusion and T1, indicated cytotoxic edema following MCA occlusion; however, APTR returned slowly toward the values determined in the contralateral hemisphere post-ischemia. These data argue that the APTR during ischemia is affected not only by pHi but by other physicochemical factors as well, and indicates different aspects of pathology in the post-ischemic brain compared to those that influence water diffusion and T1,. Magn Reson Med 57:647,653, 2007. © 2007 Wiley-Liss, Inc. [source] Delayed changes in T1 -weighted signal intensity in a rat model of 15-minute transient focal ischemia studied by magnetic resonance imaging/spectroscopy and synchrotron radiation X-ray fluorescenceMAGNETIC RESONANCE IN MEDICINE, Issue 3 2006Xuxia Wang Abstract Previous studies have found that rats subjected to 15-min transient middle cerebral artery occlusion (MCAO) show neurodegeneration in the dorsolateral striatum only, and the resulting striatal lesion is associated with increased T1 -weighted (T1W) signal intensity (SI) and decreased T2 -weighted (T2W) SI at 2,8 weeks after the initial ischemia. It has been shown that the delayed increase in T1W SI in the ischemic region is associated with deposition of paramagnetic manganese ions. However, it has been suggested that other mechanisms, such as tissue calcification and lipid accumulation, also contribute to the relaxation time changes. To clarify this issue, we measured changes in relaxation times, lipid accumulation, and elemental distributions in the brain of rats subjected to 15-min MCAO using MRI, in vivo 1H MR spectroscopy (MRS), and synchrotron radiation X-ray fluorescence (SRXRF). The results show that a delayed (2 weeks after ischemia) increase in T1W SI in the ischemic striatum is associated with significant increases in manganese, calcium, and iron, but without evident accumulation of MRS-visible lipids or hydroxyapatite precipitation. It was also found that 15-min MCAO results in acutely reduced N-acetylaspartate (NAA)/creatine (Cr) ratio in the ipsilateral striatum, which recovers to the control level at 2 weeks after ischemia. Magn Reson Med, 2006. © 2006 Wiley-Liss, Inc. [source] Detection of the anoxic depolarization of focal ischemia using manganese-enhanced MRIMAGNETIC RESONANCE IN MEDICINE, Issue 1 2003Ichio Aoki Abstract Mismatch between diffusion- and perfusion-weighted MRI was used to indicate a treatable area following focal ischemia, called the penumbra. Activity-induced manganese contrast MRI has been reported as a new visualization method for neural activation using manganese ions as a depolarization-dependent contrast agent. It is well known that energy failure induced by cerebral ischemia produces anoxic depolarization. The purpose of this study was to detect manganese accumulation caused by permanent middle cerebral artery occlusion (MCAO) of rat brain and to compare regional differences between manganese accumulation and decreased apparent diffusion coefficient (ADC). The ratios of signal intensity of manganese-enhanced MRI in the ipsilateral cortex to that in the contralateral cortex were 171.0 ± 17.5% in MCAO group and 108.4 ± 13.2% in the sham group. In addition, the enhanced region was much smaller than the area which was detected as having a reduced ADC. Magn Reson Med 50:7,12, 2003. © 2003 Wiley-Liss, Inc. [source] Phosphorylation of retinoblastoma protein in rat brain after transient middle cerebral artery occlusionNEUROPATHOLOGY & APPLIED NEUROBIOLOGY, Issue 4 2000T. Hayashi Although mature neurones do not replicate genomic DNA, some cell cycle-related kinases are aberrantly activated in neurones after ischaemia. As hyper-phosphorylation of retinoblastoma (Rb) protein is the common pathway in mitotic signal cascade, this study investigated the phosphorylation state of the Rb protein as well as its mRNA level in rat brain after transient middle cerebral artery (MCA) occlusion. Immunohisto-chemical analysis revealed that neurones in the sham-operated brain expressed Rb protein without the hyperphosphorylated form. Immunoreactivity for the hyperphosphorylated form of Rb protein progressively increased from 1 h to 3 days after ischaemia in neurones in the MCA territory. Western blot analysis demonstrated a similar change. However, reverse transcription-polymerase chain reaction study revealed that Rb showed no definite change at the mRNA level. These results suggest that Rb protein is progressively hyper-phosphorylated in the brain after ischaemia, which may activate apoptotic mechanisms in neuronal cells of the brain after ischaemia. [source] | ||||||||||||||||||||||||||||||||||