Inhibited glutamate release by granulocyte-colony stimulating factor after experimental stroke

We investigated the ability of granulocyte-colony stimulating factor (G-CSF) on inhibiting glutamate release by microdialysis in a rat stroke model. Male Wistar rats (n=15) were treated with either intravenous saline or G-CSF (60 microg/kg) 30 min after temporary middle cerebral artery occlusion (MCAO). G-CSF significantly attenuated the release of glutamate in the infarcted striatum from 30 minutes to 180 minutes after tMCAO compared with control (p<0.05). Infarct volume in G-CSF treated group (135+/-13 mm(3)) reduced significantly compared to control (181+/-10mm(3)) at 24 hours after tMCAO. The result of present study show that G-CSF possess an ability to inhibit excitotoxicity after ischemic stroke.     

辛伐他汀预处理对脑缺血再灌注损伤Bcl-2和Bax表达的影响

目的:探讨辛伐他汀预处理对大鼠局灶性脑缺血再灌注损伤的保护作用及其机制。方法:随机将48只雄性SD大鼠分为4组:空白对照组、假手术组、缺血再灌注组和辛伐他汀预处理组。辛伐他汀预处理组在模型制备前用辛伐他汀20mg/kg连续灌胃10d,1次/d;假手术组及缺血再灌注组用相同体积的等渗盐水连续灌胃10d。以线栓法制作大鼠大脑中动脉缺血再灌注模型,于缺血2h再灌注24h后行5分制神经功能评分,并断头取脑分别测定脑梗死体积、凋亡细胞数及Bcl-2、Bax表达。结果:与空白对照组和假手术组比较,缺血再灌注组和辛伐他汀预处理组神经功能缺损较为严重,脑梗死体积增大,凋亡细胞数目增多,Bcl-2、Bax表达增加(均P0.01)。与缺血再灌注组相比,辛伐他汀预处理组神经功能有不同程度改善,脑梗死体积明显减小,凋亡细胞数及Bax表达降低,Bcl-2表达增高,比较差异均有统计学意义(P0.05,P0.01)。结论:辛伐他汀预处理对大鼠脑缺血再灌注有神经保护作用,其作用机制可能与辛伐他汀上调脑组织中Bcl-2、下调Bax表达,抑制细胞凋亡有关。     

The effect of heliox treatment in a rat model of focal transient cerebral ischemia

Manipulation of inhaled gases during ischemia/reperfusion is a potential novel therapy for acute stroke. We previously found that treatment with a mixture of 70%/30% helium/oxygen (heliox) or 100% oxygen protects the brain against acute focal ischemia–reperfusion injury. This study evaluates the potential neuro-protective effects of delayed heliox treatment and its dose response effects in a rat transient focal cerebral ischemia model. Adult male rats were subjected to 2-h middle cerebral artery occlusion and then assigned to 1 of 4 inhaled gas exposure groups: I: 70%/30% nitrogen/oxygen (control); II: 70%/30% helium/oxygen administered immediately after occlusion; III: 70%/30% helium/oxygen administered after a 30–60 min delay; or, IV: 40%/30%/30% nitrogen/helium/oxygen administered immediately after occlusion. Outcome measurements included infarct size and neurological deficit score. Mean infarct sizes from groups I to IV were 228, 35, 109, and 124 mm³ respectively (p = 0.012). Only group II had significantly smaller infarct size compared to the control group (p = 0.008). In addition, only Group II had a significantly lower neurological deficit score at 24 h post ischemia when compared to the control group (p < 0.001). Since heliox reduced infarct size and improved neurological deficit scores if initiated immediately after onset of ischemia, it may be a useful adjuvant to other stroke therapies.     

雌激素对慢性脑缺血大鼠海马神经元的保护作用

目的:探讨雌激素对慢性脑缺血大鼠海马神经元的保护作用.方法:采用永久结扎去势大鼠双侧颈总动脉的方法建立慢性脑缺血模型,项背部皮下注射17β-雌二醇.硫堇染色观察海马神经元的形态变化,SP免疫组织化学法观察海马神经元胆碱乙酰基转移酶(ChAT)、细胞凋亡抑制蛋白Bcl-2和细胞凋亡促进蛋白Bax的表达.结果:模型组大鼠海马神经元排列松散,大小不规则,部分细胞固缩深染,核固缩.雌激素治疗组海马神经元细胞形态、大小与正常接近,偶见个别神经细胞胞核固缩,胞质浓染.与模型组同时间点相比,雌激素治疗组各时间点海马神经元Bcl-2和ChAT蛋白的表达升高,Bax蛋白的表达降低,且均呈时间依赖性.结论:雌激素可通过抑制海马神经元凋亡、上调海马神经元ChAT的表达,发挥对慢性脑缺血大鼠海马神经元的保护作用.     

Influence of duration of focal cerebral ischemia and neuronal nitric oxide synthase on translocation of apoptosis-inducing factor to the nucleus

Translocation of apoptosis-inducing factor (AIF) from the mitochondria to the nucleus can play a major role in neuronal death elicited by oxidant stress. The time course of nuclear translocation of AIF after experimental stroke may vary with the severity of injury and may be accelerated by oxidant stress associated with reperfusion and nitric oxide (NO) production. Western immunoblots of AIF on nuclear fractions of ischemic hemisphere of male mice showed no significant increase with 1 h of middle cerebral artery occlusion and no reperfusion, whereas increases were detectable after 6 and 24 h of permanent ischemia. However, as little as 20 min of reperfusion after 1 h of middle cerebral artery occlusion resulted in an increase in nuclear AIF coincident with an increase in poly(ADP-ribose) polymer (PAR) formation. Further nuclear AIF accumulation was seen at 6 and 24 h of reperfusion. In contrast, 20 min of reperfusion after 2 h of occlusion did not increase nuclear AIF. In this case, nuclear AIF became detectable at 6 and 24 h of reperfusion. With brief occlusion of 30 min duration, nuclear AIF remained undetectable at both 20 min and 6 h and became evident only after 24 h of reperfusion. Inhibition of neuronal NO synthase attenuated formation of PAR and nuclear AIF accumulation. Gene deletion of neuronal NO synthase also attenuated nuclear AIF accumulation. Therefore, reperfusion accelerates AIF translocation to the nucleus when focal ischemia is of moderate duration (1 h), but is markedly delayed after brief ischemia (30 min). Nuclear translocation of AIF eventually occurs with prolonged focal ischemia with or without reperfusion. Neuronally-derived NO is a major factor contributing to nuclear AIF accumulation after stroke.     

Spatio-temporal expression of cysteinyl leukotriene receptor-2 mRNA in rat brain after focal cerebral ischemia

Cysteinyl leukotrienes (CysLTs) induce inflammatory responses mediated by activating CysLT(1) and CysLT(2) receptors. We have recently reported that CysLT(1) receptor expression is increased in rat brain after focal cerebral ischemia and the increased expression is spatio-temporally related to acute neuronal injury and late astrocyte proliferation. Here we report spatio-temporal expression of CysLT(2) receptor mRNA in rat brain after focal cerebral ischemia induced by 30min of middle cerebral artery occlusion. We found that the neuron density was gradually decreased or disappeared in the ischemic core and boundary zone during 14 days after reperfusion, and the astrocyte population in the boundary zone was increased 3-14 days after reperfusion. In the ischemic core, the expression of CysLT(2) receptor mRNA was increased at 6, 12 and 24h and then recovered at 3, 7 and 14 days after reperfusion. In the boundary zone, the expression was significantly increased 3, 7 and 14 days after reperfusion. The results suggest that CysLT(2) receptor may be related to the acute neuronal injury and late astrocyte proliferation in the ischemic brain.     

Therapeutic effects of nilvadipine on rat focal cerebral ischemia

The present study was conducted to invetigate the therapeutic effects of nilvadipine, a Ca²⁺ entry blocker, on rat focal cerebral ischemia. Under halothane anesthesia, a 3-0 nylon thread was introduced into the neck internal carotid artery to occlude the left middle cerebral artery. Either nilvadipine (3.2 mg/kg) or vehicle was administered subcutaneously 1, 2, 3, 4, 5 and 6 h following the occlusion (groups 1–6, respectively). Twenty-four hours after the occlusion, the percentage infarct volumes in nilvadipine-treated animals in groups 1–3 (21±11%, 24±11%, and 26±7%, respectively) were smaller than those in the respective control groups (36±5%, 35±3%, and 35+3%; P<0.05). Compared with controls, the infarct size of the periphery of the fronto-parietal cortex decreased in nilvadipine-treated animals. The results indicate that nilvadipine decreases the size of infarction when administered up to 3 h after an ischemic insult. Thus, nilvadipine can be considered a potential therapeutic agent for acute focal cerebral ischemia, and may be clinically useful in stroke patients.     

The effect of heliox treatment in a rat model of focal transient cerebral ischemia

At nerve terminals G protein coupled receptors modulate neurotransmitter release probability. We recently showed that prolonged activation of metabotropic glutamate receptor 7, mGlu7 receptor, potentiates glutamate release. This signalling involves phospholipase C activation via a pertussis toxin insensitive G protein, the hydrolysis of phosphatidylinositol (4,5)-bisphosphate, and the subsequent activation of the non-kinase diacylglycerol binding protein Munc13-1 which primes synaptic vesicle for exocytosis at the active zone. Here we found that inhibitors of diacylglycerol metabolism (diacylglycerol kinase inhibitor II and diacylglycerol lipase inhibitor RHC80267) remarkably reduce the time of mGlu7 receptor stimulation required for glutamate release potentiation in mice cerebrocortical nerve terminals. We conclude that changes in diacylglycerol levels at nerve terminals control the efficiency of the exocytotic release machinery.     

脂肪来源的干细胞移植对大鼠脑缺血后神经细胞凋亡及Bcl-2、caspase-12表达的影响

目的:探讨脂肪来源的干细胞(ADSCs)移植对大鼠脑缺血后神经细胞凋亡的影响及其机制研究。方法:72只清洁级成年雄性Sprague-Darley大鼠,随机分为假手术组(Sham组)、局灶性脑缺血组(MCAO组)、溶剂对照组(Vehicle组)和ADSC治疗组(ADSC组),每组18只,采用改良Zea-Longa线栓法制作大脑中动脉栓塞(MCAO)模型,ADSC组于造模成功1d后经侧脑室注射入30μL的ADSC细胞悬液(内含1×106个细胞),分别于术后4d、7d和14d采用TUNEL法检测缺血区神经细胞凋亡,用免疫组织化学法和RT-PCR法检测脑组织Bcl-2、caspase-12表达的变化。结果:大鼠脑缺血后缺血周边区可见大量细胞凋亡,ADSC组较MCAO组和Vehicle组细胞凋亡明显减少(P<0.05);ADSC组术后4d、7d和14d脑组织中Bcl-2的表达水平较MCAO组和Vehicle组明显增高(P<0.05),而caspase-12的表达水平较MCAO组和Vehicle组明显降低(P<0.05)。结论:ADSCs移植减少脑缺血大鼠缺血区细胞凋亡,其机制可能与促进Bcl-2的表达和抑制caspase-12的表达有关。     

Effects of transient focal cerebral ischemia in mice deficient in puma

Bcl-2 homology domain 3 (BH3)-only pro-apoptotic proteins may play an important role in upstream cell death signaling pathways underlying ischemic brain injury. Puma is a potent BH3-only protein that can be induced via p53, FoxO3a and endoplasmic reticulum stress pathways and is upregulated by global cerebral ischemia. To more completely define the contribution of Puma to ischemic brain injury we measured the expressional response of Puma to transient focal cerebral ischemia in mice and also compared infarct volumes in puma-deficient versus puma-expressing mice. Real-time quantitative PCR determined puma mRNA levels were significantly increased 8 h after 90 min middle cerebral artery (MCA) occlusion in the ipsilateral cortex, while expression remained unchanged contralaterally. Puma protein levels were also increased in the ischemic cortex over the same period. However, cortical and striatal infarct volumes were not significantly different between puma-deficient and puma-expressing mice at 24 h, and no differences between genotypes were found for post-ischemic neurological deficit scores. These data demonstrate that focal cerebral ischemia is associated with puma induction but suggest that Puma does not contribute significantly to lesion development in the present model.     

粒细胞集落刺激因子对小鼠急性脊髓损伤的神经保护作用及其机制

目的 探讨粒细胞集落刺激因子（G-CSF）对急性脊髓损伤条件下神经保护作用的具体机制。方法 建立小鼠半切脊髓损伤模型。体内实验于造模成功术后第1天开始,给予G-CSF,连续3天,进行Basso-Beattie-Bresnahan (BBB)评分后处死,取脊髓组织进行免疫荧光及免疫印迹（Western blotting）检测。体外培养神经元,建立机械损伤细胞模型,进行形态学观察及缺口末端标记（TUNEL）染色。结果 G-CSF能够促进急性脊髓损伤后运动功能的修复,粒细胞集落刺激因子受体与核磷蛋白（NPM1     

Carcinosarcoma of the liver producing granulocyte-colony stimulating factor

An autopsy case of carcinosarcoma of the liver producing granulocyte-colony stimulating factor (G-CSF) is reported. The patient, a 74-year-old Japanese man, presented with multiple liver masses. His serum G-CSF was elevated to 286 pg/mL and a marked leukocytosis of 19 100/microL was observed. The patient had a rapidly aggravated clinical course and died 57 days after admission. Autopsy revealed a liver carcinosarcoma composed both of hepatocellular carcinoma (HCC) and sarcomatous elements immunoreactive with alpha-smooth muscle actin and desmin. Immunohistochemistry revealed positive staining of G-CSF in the cytoplasm of HCC, whereas none of the spindle cells was positively stained. Production of G-CSF was also confirmed by enzyme-linked immunosorbent assay, using the frozen tumor tissue taken at the autopsy. Similar to the majority of G-CSF-producing tumors in the literature, only the epithelial elements of the present case were immunopositive for G-CSF. Although a monoclonal origin of carcinosarcomas has generally been proposed, heterologous differentiation from a single clone might lead to the production of G-CSF only in the epithelial element in the present case. It is suggested that G-CSF was associated with the high-grade transformation of the epithelial elements, as well as the reported phenomenon of conventional HCC producing G-CSF.     

Isoflurane preconditioning improves short-term and long-term neurological outcome after focal brain ischemia in adult rats

Isoflurane preconditioning improved short-term neurological outcome after focal brain ischemia in adult rats. It is not known whether desflurane induces a delayed phase of preconditioning in the brain and whether isoflurane preconditioning-induced neuroprotection is long-lasting. Two months-old Sprague–Dawley male rats were exposed to or were not exposed to isoflurane or desflurane for 30 min and then subjected to a 90 min middle cerebral arterial occlusion (MCAO) at 24 h after the anesthetic exposure. Neurological outcome was evaluated at 24 h or 4 weeks after the MCAO. The density of the terminal deoxynucleotidyl transferase biotinylated UTP nick end labeling (TUNEL) positive cells in the penumbral cerebral cortex were assessed 4 weeks after the MCAO. Also, rats were pretreated with isoflurane or desflurane for 30 min. Their cerebral cortices were harvested for quantifying B-cell lymphoma-2 (Bcl-2) expression 24 h later. Here, we showed that pretreatment with 1.1% or 2.2% isoflurane, but not with 6% or 12% desflurane, increased Bcl-2 expression in the cerebral cortex, improved neurological functions and reduced infarct volumes evaluated at 24 h after the MCAO. Isoflurane preconditioning also improved neurological functions and reduced brain infarct volumes in rats evaluated 4 weeks after the MCAO. Isoflurane preconditioning also decreased the density of TUNEL-positive cells in the penumbral cerebral cortex. We conclude that isoflurane preconditioning improves short-term and long-term neurological outcome and reduces delayed cell death after transient focal brain ischemia in adult rats. Bcl-2 may be involved in the isoflurane preconditioning effect. Desflurane pretreatment did not induce a delayed phase of neuroprotection.     

bFGF在局灶性脑缺血后内源性神经干细胞增殖过程中对Id2的影响

目的检测DNA结合抑制物2(inhibitor of DNA binding 2,Id2)在大鼠脑缺血再灌注海马组织神经干细胞中的表达及bFGF的干预作用。探讨影响神经干细胞增殖分化的分子调控机制。方法采用大脑中动脉栓塞(MCAO)制作大鼠脑缺血再灌注模型。用免疫组织化学法检测海马神经干细胞BrdU、Id2的表达及bFGF的干预作用。结果随着脑缺血再灌注第3天缺血海马神经元BrdU阳性细胞明显增多,第7天达高峰,Id2反应产物脑缺血再灌注第3天较正常组增多,随缺血再灌注时间的延长逐渐增多,第7天表达最强,以后表达逐渐减少。注射bFGF后BrdU、Id2的表达明显增加。结论 bFGF促进神经干细胞的增殖及缺血脑组织Id2的表达,提示bFGF促进神经干细胞增殖作用可能由Id2信号介导。     

小檗碱减轻大鼠心肌缺血再灌注损伤

目的探讨小檗碱(BBR)减轻大鼠心肌缺血再灌注(MI/R)损伤的作用及其与JAK2/STAT3信号通路的关系。方法雄性SD大鼠(250只)随机分为7组(n=36):假手术组(sham)、sham+BBR组、sham+AG490(AG,JAK2/STAT3通路抑制剂)组、MI/R+溶剂组(MI/R+V)、MI/R+BBR组、MI/R+BBR+AG组、MI/R+AG组。常规结扎大鼠冠状动脉左前降支行心肌缺血再灌注手术,缺血30 min后再灌注4 h,用Western blot法检测心肌JAK2、STAT3磷酸化水平及心肌凋亡相关蛋白表达,再灌注6 h后检测心肌细胞凋亡率、梗死面积及氧化应激相关指标,再灌注72 h后检测心功能。结果 BBR可显著改善心肌缺血再灌注术后心功能并减轻心肌凋亡及梗死,这种保护作用可被AG阻断(均P0.05)。BBR治疗还可显著提高心肌JAK2及STAT3磷酸化水平,抑制凋亡相关信号分子表达,这种作用也被AG阻断(P0.05)。结论 BBR可显著减轻大鼠MI/R损伤后心肌梗死及凋亡水平,改善心功能,JAK2/STAT3可能介导此作用。     

行为学训练对缺血性脑损伤大鼠脑组织X盒结合蛋白1表达的影响

目的:研究大鼠脑缺血再灌注后对细胞核转录因子X盒结合蛋白1(XBP1)表达的影响,探讨穿梭箱行为学训练对脑缺血再灌注大鼠脑组织XBP1的调节作用及机制.方法:应用线栓法制作大鼠局灶性脑缺血再灌注模型,训练组于造模1d后开始给予穿梭箱训练,采用免疫组织化学检测不同时间点大脑皮质内XBP1的表达.结果:正常对照组大鼠大脑皮质内XBP1少量表达,缺血再灌注后高于正常对照组,训练组大脑皮质内XBP1阳性表达较缺血再灌注组明显增多.结论:穿梭箱训练上调脑缺血诱导的XBP1表达,对脑缺血再灌注大鼠皮质神经元的具有保护作用.     

Whole-body periodic acceleration reduces brain damage in a focal ischemia model

Stroke is the second most common cause of death and major cause of disability worldwide. Actual treatment involves surgery and/or thrombolytic drugs, but there is an urgent need for new approaches. Periodic acceleration, a rocking headward to footward movement of the whole body, is a non-invasive method to induce pulsatile shear stress on the vascular endothelium eliciting an enhanced production and secretion of endothelium-derived products such as nitric oxide, prostacyclin, prostaglandin E2, tissue plasminogen activator (tPA), and adrenomedullin. All these products have been shown to protect the brain from ischemic injuries. A rat model of focal brain ischemia was treated with application of periodic acceleration for 3 h immediately after the onset of ischemia. Controls remained static for the same period of time. Brain damage was assessed by magnetic resonance imaging (MRI) and biochemical markers. A significant reduction in brain damage was observed, 7 days post-ischemia, in rocked rats when compared with the static controls, through MRI. Furthermore, rocked animals had significantly lower levels of Beclin 1 and fractin than their static counterparts, and some isoforms of nitric oxide synthase were regulated by periodic acceleration. Our results show that periodic acceleration may provide a novel, affordable, non-invasive therapeutic option for the treatment of stroke.     

基因表达谱芯片筛选局灶性脑缺血大鼠脑相关基因的研究

目的:应用基因芯片技术研究局灶性脑缺血大鼠脑组织与假手术组大鼠脑组织基因表达谱的差异,探索局灶性脑缺血的发病机制。方法:将4096种大鼠基因PCR产物用CartesianPixsys7500点样仪按微矩阵排列制成基因芯片;按一步法抽提脑局灶性缺血大鼠脑组织与假手术组大鼠脑组织的总RNA;将等量的脑局灶性缺血大鼠脑组织与假手术组大鼠脑组织RNA分别逆转录合成以Cy5和Cy3标记的cDNA一链做探针,混合后与上述基因芯片杂交。用AxonGenepix4000B扫描仪扫描芯片荧光信号图像,用GenepixPro4.0软件进行数字化处理和分析后比较两种组织基因表达谱的差异。结果:局灶性脑缺血大鼠与假手术组大鼠脑组织基因表达谱分析,发现211个差异表达基因,其中12个基因低表达,199个基因高表达。结论:本研究从脑局灶性缺血大鼠脑组织中筛选出大量的差异表达基因,说明这些基因可能参与局灶性脑缺血后脑损伤的发生及发展过程,从而为局灶性脑缺血的诊治提供新思路。     

缺血后适应对大鼠局灶性脑缺血再灌注后谷氨酸的影响

目的:研究缺血后适应对大鼠局灶性脑缺血再灌注后谷氨酸(Glu)浓度变化的影响。方法:建立大鼠大脑中动脉阻塞(middle cerebral artery occlusion,MCAO)模型,将36只雄性SD大鼠随机分为假手术(Sham)组、脑缺血再灌注(I/R)组和缺血后适应(I Postcond)组,每组12只。应用高效液相色谱检测缺血脑组织匀浆Glu浓度。结果:局灶脑缺血再灌注6 h后,I Postcond组Glu浓度相较I/R组明显降低(P<0.01),局灶脑缺血再灌注24 h后,I Postcond组Glu浓度较I/R组低,但两者差异亦无显著性(P>0.05)。结论:本研究表明,I Postcond能够减轻MCAO大鼠模型中I/R损伤。细胞间隙Glu清除的加速可能是其重要保护机制之一。