美满霉素抑制血管性认知功能损伤大鼠海马星型胶质细胞激活和神经炎症(英文)

目的观察美满霉素(minocycline)对血管性认知功能损伤大鼠海马组织GFAP、COX-2、NF-κB、IL-1β和TNF-α表达的影响,探讨美满霉素对血管性认知功能损伤脑保护作用的机制。方法Wistar大鼠随机分为假手术组(S组)、血管性认知功能损伤模型组(M组)和美满霉素治疗组(MT组)。免疫组织化学法检测大鼠海马组织COX-2和NF-κB的表达,蛋白质印迹和免疫组织化学法检测大鼠海马组织GFAP的表达,ELISA法检测大鼠海马组织IL-1β和TNF-α的表达。结果MT 组 GFAP、COX-2、NF-κB、IL-1β和 TNF-α表达较 M 组均降低(P<0.01) ;MT 和 M 组GFAP、COX-2、NF-κB、IL-1β和 TNF-α表达均显著高于 S 组(P<0.01)。结论美满霉素能降低血管性认知功能损伤大鼠海马组织中GFAP、COX-2、NF-κB、IL-1β和TNF-α的表达,抑制血管性认知功能损伤大鼠海马星型胶质细胞活化和神经炎症,发挥脑保护作用。     

一种C-Jun N-末端激酶肽抑制剂在沙土鼠全脑缺血中的保护作用

目的 为了进一步研究海马C1区域神经细胞活动中JNK的作用，我们评价了一种JNK抑制剂即D-JNKI1在沙土鼠一过性大脑缺血模型中对迟发性神经细胞死亡（DND）的作用。方法 55只沙土鼠随机分为11个组。5组沙土鼠先接受5min前脑缺血处理，再灌注3h后，通过立体定向方法。向每组沙土鼠右侧侧脑室内分别注入不同浓度的D-JNKI1（2μL PBS内加入0．00012，0．0012，0．012，0．12，1．2μmol／L D-JNKI1，每组n=5）。对照组（n=5）：沙土鼠先接受5min前脑缺血处理，再灌注3h后，通过立体定向方法方法向右侧侧脑室内仅注入PBS2μL。腹腔内注射组（n=5）沙土鼠；先接受5min前脑缺血处理，再灌注3h后，1．2μmol／L D-JNKI1溶于0．5mL PBS腹腔内注射。假手术组（n=5）；沙土鼠仅暴露双侧颈总动脉，未夹闭。预处理组（共3组，n=15）：先将0．0012μmol／L D-JNKI1，0．00012μmol／L D-JNKI1溶于2μL PBS，分别注入两组沙土鼠的右侧侧脑室内，另外一组沙土鼠的右侧侧脑室内仅仅注入PBS2μL，30min后三组均夹闭双侧颈总动脉2min，48h后再次接受双侧颈总动脉夹闭5min。所有沙土鼠从接受夹闭5min双侧颈总动脉后4d处死，作冰冻切片和Niss1染色。结果 缺血再灌注3h后用D-JNKI-1治疗，有神经保护作用，最好的神经保护效应浓度为0．0012μmol／L。D-JNKI-1预处理加强了2min预处理所诱导的缺血耐受效应。结论D-JNKI1在沙土鼠全脑缺血模型中对海马CA1区域的迟发性神经细胞死亡有潜在的神经保护作用。     

The effect of granulocyte-colony stimulating factor in global cerebral ischemia in rats

Granulocyte-colony stimulating factor (G-CSF) is an endogenous peptide hormone of the hematopoietic system that has entered Phase I/II clinical trials for treatment of ischemic stroke. Severe intraoperative hypotension can lead to global cerebral ischemia and apoptotic neuron loss within the hippocampus. We tested G-CSF in a rat model of global cerebral ischemia. Global cerebral ischemia was induced in male Sprague-Dawley rats (280-330 g) with the 2-vessel occlusion model (hemorrhagic hypotension to a mean arterial pressure of 30-35 mm Hg and bilateral common carotid artery occlusion for 8 min). Three groups of animals were used: global ischemia without treatment (GI, n=49), global ischemia with G-CSF treatment (GI+G-CSF, n=42), and sham surgery (Sham, n=26). Rats in the treatment group received G-CSF (50 mug/kg, subcutaneously) 12 h before surgery, on the day of surgery, and on postoperative Day 1 and were euthanized on Days 2, 3, and 14. Mild hyperglycemia was observed in all groups. T-maze testing for spontaneous alternation demonstrated initial improvement in the G-CSF treatment group but no long-term benefit. Measurement of daily body weight demonstrated an initial trend toward improvement in the G-CSF group. Quantitative Nissl histology of the hippocampus demonstrated equivalent outcomes on Days 3 and 14, which was supported by quantitative TUNEL stain. Immunohistochemistry and Western blot demonstrated an initial increase in phosphorylated-AKT in the GI+G-CSF group on Day 2. We conclude that G-CSF treatment is associated with transient early improvement in neurobehavioral outcomes after global ischemia complicated by mild hyperglycemia, but no long-term protection.     

Chronic cerebral hypoperfusion induces vascular plasticity and hemodynamics but also neuronal degeneration and cognitive impairment

Chronic cerebral hypoperfusion (CCH) induces cognitive impairment, but the compensative mechanism of cerebral blood flow (CBF) is not fully understood. The present study mainly investigated dynamic changes in CBF, angiogenesis, and cellular pathology in the cortex, the striatum, and the cerebellum, and also studied cognitive impairment of rats induced by bilateral common carotid artery occlusion (BCCAO). Magnetic resonance imaging (MRI) techniques, immunochemistry, and Morris water maze were employed to the study. The CBF of the cortex, striatum, and cerebellum dramatically decreased after right common carotid artery occlusion (RCCAO), and remained lower level at 2 weeks after BCCAO. It returned to the sham level from 3 to 6 weeks companied by the dilation of vertebral arteries after BCCAO. The number of microvessels declined at 2, 3, and 4 weeks but increased at 6 weeks after BCCAO. Neuronal degeneration occurred in the cortex and striatum from 2 to 6 weeks, but the number of glial cells dramatically increased at 4 weeks after BCCAO. Cognitive impairment of ischemic rats was directly related to ischemic duration. Our results suggest that CCH induces a compensative mechanism attempting to maintain optimal CBF to the brain. However, this limited compensation cannot prevent neuronal loss and cognitive impairment after permanent ischemia.     

Protective effect of biflavones from Araucaria bidwillii Hook in rat cerebral ischemia/reperfusion induced oxidative stress

Oxidative stress is implicated in the pathogenesis of ischemic brain injury. Flavonoids from various herbal extracts have been shown to be neuroprotective in experimental models of cerebral ischemia/reperfusion (I/R). The present study was designed to investigate the neuroprotective effect of the biflavone rich fraction from Araucaria bidwillii Hook (ABH) (Family: Araucariaceae) in I/R induced oxidative stress. The I/R was induced by occluding bilateral common carotid arteries (BCCAO) for 30 min, followed by 24 h reperfusion. BCCAO caused significant depletion in superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and significant increase in lipid peroxidation (LPO) in various brain regions. The neurological deficit and sensory motor function were also decreased significantly by BCCAO group as compared to sham group animals. All the alteration induced by cerebral ischemia was significantly attenuated by 7 days' pretreatment with biflavone fraction (BFR) at the dose of 100 and 200 mg/kg, comparable to that given by Vitamin E (200 mg/kg). Consistent with neurobehavioral deficits, pretreatment with biflavones at higher doses significantly reduced ischemia-induced neuronal loss of the brain. In conclusion the biflavone rich fraction from A. bidwillii was found to protect rat brain against I/R induced oxidative stress, and attributable to its antioxidant properties.     

运动训练对大鼠脑缺血再灌注后神经修复及GAP-43和Neurocan表达的影响

目的 观察运动训练对大鼠脑缺血再灌注后不同时间神经修复及GAP-43与Neurocan表达的影响.方法 健康雄性Wistar大鼠72只,随机分成运动训练组、对照组、假手术组.采用线栓法制作一侧大脑中动脉闭塞(MCAO)模型,以神经功能缺损评分和Morris水迷宫试验进行神经功能评价,免疫组化法观察对脑缺血周围GAP-43与Neuorcan的表达.结果 与对照组比较,脑缺血再灌注后14d、21d,运动组的肢体运动及记忆功能明显恢复;缺血再灌注后7d,对照组缺血周围出现GAP-43阳性细胞,14d减少,21d、28d明显减少,运动组GAP-43表达在14d、21d、28d较对照组显著增加(P<0.05).Neurocan阳性细胞在对照组缺血再灌注7d出现,14d达高峰,21d、28d时下降;运动组Neurocan表达在缺血再灌注14d、21d、28d较对照组显著减少(P<0.05).结论 运动训练上调大鼠脑缺血区GAP-43表达与下调Neurocan表达,可能是其促进脑损伤区中枢神经修复的重要机制之一.     

The phosphodiesterase type 2 inhibitor BAY 60‐7550 reverses functional impairments induced by brain ischemia by decreasing hippocampal neurodegeneration and enhancing hippocampal neuronal plasticity

Cognitive and affective impairments are the most characterized consequences following cerebral ischemia. BAY 60‐7550, a selective phosphodiesterase type 2 inhibitor (PDE2‐I), presents memory‐enhancing and anxiolytic‐like properties. The behavioral effects of BAY 60‐7550 have been associated with its ability to prevent hydrolysis of both cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) thereby interfering with neuronal plasticity. Here, we hypothesize that PDE2‐I treatment could promote functional recovery after brain ischemia. Mice C57Bl/6 were submitted to bilateral common carotid artery occlusion (BCCAO), an experimental model of transient brain ischemia, for 20 min. During 21 days after reperfusion, the animals were tested in a battery of behavioral tests including the elevated zero maze (EZM), object location task (OLT) and forced swim test (FST). The effects of BAY 60‐7550 were evaluated on neuronal nuclei (NeuN), caspase‐9, cAMP response element‐binding protein (CREB), phosphorylated CREB (pCREB) and brain‐derived neurotrophic factor (BDNF) expression in the hippocampus. BCCAO increased anxiety levels, impaired hippocampus‐dependent cognitive function and induced despair‐like behavior in mice. Hippocampal neurodegeneration was evidenced by a decrease in NeuN and increase incaspase‐9 protein levels in BCCAO mice. Ischemic mice also showed low BDNF protein levels in the hippocampus. Repeated treatment with BAY 60‐7550 attenuated the behavioral impairments induced by BCCAO in mice. Concomitantly, BAY 60‐7550 enhanced expression of pCREB and BDNF protein levels in the hippocampus of ischemic mice. The present findings suggest that chronic inhibition of PDE2 provides functional recovery in BCCAO mice possibly by augmenting hippocampal neuronal plasticity.     

变构促红细胞生成素对小鼠脑缺血后神经新生和血管新生的影响

目的 探讨一种氨基酸突变后无促红细胞生成能力的变构促红细胞生成素(mEPO)对大脑中动脉闭塞小鼠神经新生和血管新生的作用.方法 将30只成年雄性C57BL/B6小鼠随机分为Sham组、I/R+ Veh组和I/R+ mEPO组,每组10只.制作小鼠大脑中动脉闭塞缺血(MCAO)模型,I/R+mEPO组小鼠在再灌注即刻腹腔注入mEPO(5 000 IU/kg),I/R+ Veh组小鼠在制模后注入等体积的生理盐水.通过BrdU检测细胞增殖情况,采用转棒试验对小鼠神经功能进行评估.在脑缺血后第14天,检测3组小鼠脑组织丢失比例、神经新生及血管新生情况.结果 用mEPO处理后,I/R+mEPO组小鼠脑组织丢失比例(14.62±5.80)％显著低于I/R+ Veh组小鼠(29.81±7.75)％,差异有统计学意义(P＜0.05);I/R+mEPO组小鼠脑缺血后第3,7天神经功能均有明显改善,第7天即恢复到正常水平,差异有统计学意义(P＜0.05);I/R+mEPO组小鼠脑缺血后第14天BrdU+/NeuN+双阳性细胞数量(36.25±10.53)和BrdU+/Laminin+双阳性细胞数量(25.25±6.34)显著高于Sham组小鼠和I/R+ Veh组小鼠,差异有统计学意义(P＜0.05).结论 mEPO促进了小鼠脑缺血周边区神经新生及血管新生,从而减轻脑组织的损伤程度并提高神经功能.这种无促红细胞生成作用的mEPO可能会成为临床脑血管病的治疗药物.     

A forebrain ischemic preconditioning model established in C57Black/Crj6 mice

Although many kinds of rat and gerbil cerebral ischemic preconditioning models are available, only a focal ischemic preconditioning model in mice has been reported. As most genetic alterations have been performed in mice, it is urgent to develop mouse ischemic preconditioning models for investigating the molecular mechanisms of ischemic preconditioning in transgenic mice. In the present study, we developed a forebrain ischemic preconditioning model in C57Black/Crj6 (C57BL/6) mice. Forebrain ischemia was induced in C57BL/6 mice (8-10 weeks old) by bilateral common carotid artery occlusion (BCCAO) for 18 min. The conditioning ischemic insult lasting for 6 min was carried out 48 h before the 18-min BCCAO. On the seventh day after BCCAO, neuronal damage was visualized by microtubule-associated protein-2 immunohistochemistry and quantified by cresyl violet staining. Terminal deoxytransferase-mediated dUTP-nick end labeling (TUNEL) was performed 72 h after reperfusion to detect DNA fragmentation. Ischemia for 18 min resulted in injury to the striatum, cortex and hippocampus. In comparison to the hippocampus, striatal neuronal injury was more severe and reproducible. Although the conditioning ischemia itself caused neither noticeable striatal neuronal damage nor DNA fragmentation, it significantly reduced striatal neuronal damage and DNA fragmentation caused by the subsequent 18-min ischemia. These results indicate that striatal neuronal injury after transient BCCAO can be strongly reduced by a sublethal ischemic episode in C57BL/6 mice. As many kinds of gene-altered C57BL/6 mice are available, this preconditioning model may be useful for investigating the molecular mechanisms of ischemic preconditioning in transgenic mice.     

缺血预处理后Fas蛋白表达与迟发性神经元凋亡的关系初步探讨

目的动态观察缺血预处理后大鼠大脑皮层和海马CA1区神经元凋亡与Fas蛋白表达变化情况,初步探讨缺血预处理后Fas蛋白表达与迟发性神经元凋亡的关系。方法四血管阻断法复制全脑缺血模型,动物随机分为非缺血对照组、预处理对照组、缺血预处理组和缺血组。采用尼氏和TUNEL染色法观察皮层及海马CA1区神经元存活数和凋亡细胞数,免疫组化方法检测Fas蛋白在缺血预处理后表达变化情况。结果缺血组缺血6h在皮质及海马CA1区Fas阳性表达细胞计数升高,12h达高峰;缺血预处理组缺血12h阳性细胞计数升高,24h达高峰。缺血组缺血6h出现凋亡细胞,48h凋亡细胞数达到高峰;缺血预处理组凋亡细胞数较缺血组明显减少。缺血组缺血7d神经元数明显减少,12周时神经元大量减少;缺血预处理组缺血7d时神经元数无明显变化,但12周时神经元同样大量减少。结论全脑缺血可能通过诱导Fas蛋白的表达增多,启动细胞凋亡,导致缺血后神经元凋亡的发生;缺血预处理虽可延缓缺血后神经元的凋亡,但无法提供真正的长时期的神经元保护作用,其有限的保护作用可能是通过延缓Fas蛋白的表达而减缓了神经元凋亡的进程。     

Changes in xanthine and uric acid in rat brain after middle cerebral artery occlusion

Xanthine and uric acid, products of purine metabolism, were measured by reversed-phase high-performance liquid chromatography (HPLC) with electrochemical detection in rat forebrain following focal cerebral ischemia. Focal cerebral ischemia was induced in the rat by permanent occlusion of the left middle cerebral artery (MCA). Sprague-Dawley rats were anesthetized with halothane inhalation and left MCA was occluded via trans-retro-orbital approach. Normal and sham-operated rats were used as control animals. The animals were decapitated 2 (MCA = 5, Sham = 5), 4 (MCA = 7, Sham = 6), 8 (MCA = 5, Sham = 5), and 16 (MCA = 6, Sham = 6) hours or 1 (MCA = 5, Sham = 5), 2 (MCA = 6, Sham = 6), 7 (MCA = 7, Sham = 6), 14 (MCA = 6, Sham = 5), and 28 (MCA = 7, Sham = 5) days after the operation. The brains were removed and divided into right and left hemisphere. Each hemisphere was homogenized and centrifuged. The supernates were filtered with membrane filter. An aliquot of the filtrate was used for measurement of xanthine and uric acid in both of the ischemic and contralateral hemisphere by a HPLC system. In the normal group, xanthine and uric acid in the brain was 12.4 +/- 0.4 and 2.2 +/- 0.1 nmol/g tissue (mean +/- SEM), respectively. In the ischemic hemisphere, xanthine increased up to 57.7 +/- 5.2 nmol/g tissue 2 hours after MCA occlusion and reached a maximum value of 59.42 +/- 4.91 nmol/g tissue 4 hours following the induction of ischemia. Xanthine level was still high 8 hours after ischemia and then rapidly decreased to the normal value at day 2.(ABSTRACT TRUNCATED AT 250 WORDS)     

适度酒精预适应对大鼠局灶性脑缺血再灌注损伤保护作用的研究

目的 研究适度酒精预适应对大鼠局灶性脑缺血再灌注诱导的神经元损伤的保护作用。 方法 将36只雄性SD大鼠随机分为假手术组、缺血再灌注组和酒精预适应组,每组12只。局灶性脑 缺血再灌注模型采用右侧大脑中动脉闭塞方式,缺血2 h,再灌注24 h。酒精预适应组在脑缺血再灌 注前24 h用95%酒精与0.3 ml无菌蒸馏水混合后进行灌胃,95%酒精体积（μl）计算为：[大鼠体重（g） x0.6]+0.3。其余两组用同等剂量的生理盐水灌胃。每组取8只大鼠在缺血再灌注后24 h进行神经功能 评分和氯化2,3,5-三苯基四氮唑（2,3,5-Triphenyltetrazolium chloride,TTC）染色并根据染色结果计 算脑梗死体积。每组剩余的4只,在缺血再灌注后24 h进行磁共振T2加权像（T2-weighted imaging,T2WI） 序列扫描,然后将大鼠处死取脑,经过冷冻切片后,每只大鼠取第一躯体感觉皮质区的2张切片,1 张用末端转移酶介导的脱氧尿嘧啶核苷三磷酸缺口末端标记（terminal deoxynucleotidyl transferasemediated 2'-deoxyuridine 5'-triphosphate nick-end labeling,TUNEL）检测其凋亡性细胞死亡情况,另一 张用Fluoro-Jade B检测其神经元退化变性情况。 结果 相较于缺血再灌注组,经过适度酒精预适应后会显著降低大鼠的神经功能评分[15.00 （14.25,16.00）vs 3.50（2.25,4.00）（P <0.001）]、脑梗死体积[TTC：（242.80±17.44）mm3 vs （54.83±13.43）mm3;T2WI ：（296.80±8.53）mm3 vs（59.68±9.97）mm3,P均<0.001]、凋亡细胞所占百 分比[（33.47±2.23）% vs（9.66±0.84）%,P <0.001]和退化变性神经元所占百分比（[ 45.31±3.40）% vs（23.26±1.25）%,P <0.001]。 结论 适度酒精预适应可以保护局灶性脑缺血再灌注诱导的神经元损伤。     

Brain glutamine synthetase increases following cerebral ischemia in the rat.

Changes in astrocyte glutamine synthetase (GS) in postischemic rat brain were evaluated and correlated with regional neuronal vulnerability or resistance to ischemia. Rats subjected to 20 or 30 min of cerebral ischemia were allowed to survive for 3 or 24 h after ischemia; normal animals served as controls. Resultant neuronal necrosis was severe in the striatum by 24 h and in the CA1 region of the hippocampus at 72 h; neurons in paramedian cortex and CA3 region of the hippocampus were not permanently damaged. Glutamine synthetase (GS) immunocytochemistry was performed on vibratome sections of paraformaldehyde-fixed brains and enzyme activity was assayed in frozen samples of cerebral cortex, striatum and hippocampus. At 3 and 24 h after ischemia, GS immunoreactivity increased and was secondary to enlargement of GS-positive cell bodies and processes as well as to increased numbers of GS-positive astrocytes. Enzyme activity also increased in cortex, striatum and hippocampus at 3 and 24 h (P less than or equal to 0.03). This study shows that increase in astrocyte GS occurs rapidly after ischemia, and prior studies indicate that this increase occurs in parallel with proliferative changes in astrocyte organelles. The results also suggest that astrocyte metabolism of glutamate increases after ischemia. The increased capacity for glutamine synthetase may be important in normalizing extracellular glutamate following ischemia and protecting brain from the neurotoxic effects of this excitatory amino acid.     

不同时间脑室注射BDNF对大鼠脑缺血再灌注损伤的保护作用

目的 观察大鼠脑缺血再灌注(I/R)损伤前后不同时间脑室注射外源性脑源性神经营养因子(BDNF)对脑损伤的影响. 方法 70只成年雄性Wistar大鼠,按照随机数字表法分为7组(n=10):正常对照组(C组)、缺血再灌注组(I/R组)、缺血前12、6 h、缺血即刻及再灌注6、12 h BDNF给药组(即 A1组、A2组、A3组、A4组、A5组).采用线栓法建立大鼠大脑中动脉阻塞(MCAO)I/R模型,给药各组分别于上述各时间点经侧脑室注射0.5μg BDNF.观察缺血侧脑组织超氧化物歧化酶(SOD)、丙二醛(MDA)及脑皮层凋亡神经细胞的变化,并每组随机取一术侧大脑皮层1 mm×1 mm组织块作电镜标本,观察脑组织超微结构的改变.结果 与I/R组比较,BDNF侧脑室给药各组脑组织SOD活性明显增强,MDA含量明显降低,脑皮层神经细胞凋亡指数明显降低,差异有统计学意义(P<0.05).A1、A2组较其他给药组脑组织SOD活性较高(分别为25.02±2.77、24.01±1.03),MDA含量(分别为10.35±1.23、12.29±0.92)以及神经细胞凋亡指数(分别为21.77±3.56、23.84±2.63)较低,差异有统计学意义(P<0.05).BDNF给药各组脑组织超微结构损伤改变不大或仅有轻微的改变,而I/R组脑组织超微结构表现出严重的损伤. 结论 不同时间脑室注射外源性BDNF对大鼠局灶性脑I/R损伤有不同程度的保护作用,且具有较强的时间依赖性,以缺血前应用的脑保护效果较为明显,其机制可能与BDNF能够增加体内抗氧化物质SOD的活性及抑制神经细胞凋亡等有关.     

Effects of CXCR7-neutralizing antibody on neurogenesis in the hippocampal dentate gyrus and cognitive function in the chronic phase of cerebral ischemia

Stromal cell-derived factor-1 and its receptor CXCR4 are essential regulators of the neurogenesis that occurs in the adult hippocampal dentate gyrus.However,the effects of CXCR7,a new atypical receptor of stromal cell-derived factor-1,on hippocampal neurogenesis after a stroke remain largely unknown.Our study is the first to investigate the effect of a CXCR7-neutralizing antibody on neurogenesis in the dentate gyrus and the associated recovery of cognitive function of rats in the chronic stage of cerebral ischemia.The rats were randomly divided into sham,sham+anti-CXCR7,ischemia and ischemia+anti-CXCR7 groups.Endothelin-1 was injected in the ipsilateral motor cortex and striatum to induce focal cerebral ischemia.Sham group rats were injected with saline instead of endothelin-1 via intracranial injection.Both sham and ischemic rats were treated with intraventricular infusions of CXCR7-neutralizing antibodies for 6 days 1 week after surgery.Immunofluorescence staining with doublecortin,a marker for neuronal precursors,was performed to assess the neurogenesis in the dentate gyrus.We found that anti-CXCR7 antibody infusion enhanced the proliferation and dendritic development of doublecortin-labeled cells in the dentate gyrus in both ischemic and sham-operated rats.Spatial learning and memory functions were assessed by Morris water maze tests 30-32 days after ischemia.CXCR7-neutralizing antibody treatment significantly reduced the escape latency of the spatial navigation trial and increased the time spent in the target quadrant of spatial probe trial in animals that received ischemic insult,but not in sham operated rats.These results suggest that CXCR7-neutralizing antibody enhances the neurogenesis in the dentate gyrus and improves the cognitive function after cerebral ischemia in rats.All animal experimental protocols and procedures were approved by the Institutional Animal Care and Use Committee of China Medical University(CMU16089 R)on December 8,2016.     

Aerobic exercise combined with huwentoxin-I mitigates chronic cerebral ischemia injury

Ca2+ channel blockers have been shown to protect neurons from ischemia, and aerobic exercise has significant protective effects on a variety of chronic diseases. The present study injected huwentoxin-I (HWTX-I), a spider peptide toxin that blocks Ca2+ channels, into the caudal vein of a chronic cerebral ischemia mouse model, once every 2 days, for a total of 15 injections. During this time, a subgroup of mice was subjected to treadmill exercise for 5 weeks. Results showed amelioration of cortical injury and improved neurological function in mice with chronic cerebral ischemia in the HWTX-I + aerobic exercise group. The combined effects of HWTX I and exercise were superior to HWTX-I or aerobic exercise alone. HWTX-I effectively activated the Notch signal transduction pathway in brain tissue. Aerobic exercise up-regulated synaptophysin mRNA expression. These results demonstrated that aerobic exercise, in combination with HWTX-I, effectively relieved neuronal injury induced by chronic cerebral ischemia via the Notch signaling pathway and promoting synaptic regeneration.     

The chronic vascular and haemodynamic response after permanent bilateral common carotid occlusion in newborn and adult rats.

Vascular growth and redistribution of flow can compensate for arterial occlusion and possibly reduce the effects of hypoperfusion. As yet there is limited information on the age-dependent nature of vasculature remodelling. In this study, we have monitored the vascular and morphologic changes using magnetic resonance imaging and histology in a chronic bilateral common carotid artery occlusion (BCCAO) model in both newborn and adult rats. Acutely, cerebral blood flow (CBF) decreased immediately after BCCAO, producing a state of oligemic hypoperfusion. At 6 months after BCCAO in both adult and neonatal rats, the CBF had normalised at control values. To investigate the underlying mechanism for the return of CBF to control values, intra- and extracerebral magnetic resonance angiograms (MRAs) were acquired. As expected, signal from the common carotid arteries was present in the sham-operated rats, but was absent in the BCCAO animals. India ink angiograms demonstrated more tortuous basilar arteries in the adult rats post-BCCAO and MRAs demonstrated more extracerebral midline collaterals in the neonatal rats post-BCCAO, indicating different modes of vascular adaptation dependent on the age at onset of the insult. Both groups had collateral vessels arising from the vertebral arteries, and BCCAO was also associated with increased diameter of basilar, posterior cerebral, posterior communicating, internal carotid, middle cerebral and anterior cerebral arteries. Our study suggests that the developing and mature animals exhibit different patterns of vascular remodelling and that the BCCAO hypoperfusion model will be useful for investigating age-dependent vascular events in response to vaso-occlusive disease.     

米诺环素对慢性脑缺血大鼠脑内Notch信号通路的影响

目的 观察慢性脑缺血后米诺环素是否可以通过调节Notch信号通路而发挥脑保护作用。方法 将健康雄性SD大鼠40只随机分为5组(n=8):假手术(Sham)组、缺血模型(Model)组、DAPT组、米诺环素(Min)组、DAPT+米诺环素(DAPT+Min)组; 双侧颈总动脉永久性结扎(2-VO)建立慢性脑缺血模型,给药1月后行为学检测大鼠的学习记忆能力,免疫组化和Western blot检测VEGF及Notch信号通路下游物质Hes1的表达水平。结果 与假手术组比较,缺血模型组大鼠的学习记忆能力降低(P<0.05); 米诺环素组与DAPT组比较,VEGF及Hes1的表达水平存在显著差异(P<0.01); 米诺环素组分别于与缺血模型组和DAPT+米诺环素组比较,DAPT+米诺环素组与DAPT组比较,学习记忆能力、VEGF及Hes1的表达水平存在显著差异(P<0.05)。结论 米诺环素可能通过对慢性脑缺血大鼠脑内Notch信号通路的调节来促进脑缺血后血管的新生,进而发挥脑保护作用。     

Leukocyte Recruitment and Ischemic Brain Injury

Leukocytes are recruited into the cerebral microcirculation following an ischemic insult. The leukocyte–endothelial cell adhesion manifested within a few hours after ischemia (followed by reperfusion, I/R) largely reflects an infiltration of neutrophils, while other leukocyte populations appear to dominate the adhesive interactions with the vessel wall at 24 h of reperfusion. The influx of rolling and adherent leukocytes is accompanied by the recruitment of adherent platelets, which likely enhances the cytotoxic potential of the leukocytes to which they are attached. The recruitment of leukocytes and platelets in the postischemic brain is mediated by specific adhesion glycoproteins expressed by the activated blood cells and on cerebral microvascular endothelial cells. This process is also modulated by different signaling pathways (e.g., CD40/CD40L, Notch) and cytokines (e.g., RANTES) that are activated/released following I/R. Some of the known risk factors for cardiovascular disease, including hypercholesterolemia and obesity appear to exacerbate the leukocyte and platelet recruitment elicited by brain I/R. Although lymphocyte–endothelial cell and –platelet interactions in the postischemic cerebral microcirculation have not been evaluated to date, recent evidence in experimental animals implicate both CD4+ and CD8+ T-lymphocytes in the cerebral microvascular dysfunction, inflammation, and tissue injury associated with brain I/R. Evidence implicating regulatory T-cells as cerebroprotective modulators of the inflammatory and tissue injury responses to brain I/R support a continued focus on leukocytes as a target for therapeutic intervention in ischemic stroke.     

Apelin/APJ信号系统对脑缺血后血管内皮细胞修复及机制的研究

目的 探讨Apelin/APJ信号系统对脑缺血损伤的血管内皮细胞的修复作用.方法 采用电凝烧灼法制备局灶性大脑皮质梗死模型,通过侧脑室注射腺病毒Ad-Apelin或对照病毒Ad-RFP.实验动物随机分为4组,分别为假手术(sham)组、脑梗死组(MCAO)、Ad-Apelin+脑梗死组(Ad-Apelin)组、Ad-R...