产前应激对成年子代大鼠缺血性卒中后细胞凋亡的影响

目的:研究产前应激对雄性子代大鼠大脑中动脉缺血/再灌注后神经功能的影响。方法:SD孕鼠随机进行产前应激处理(孕期每日3次限制活动)和无产前应激处理,并对其雄性子代大鼠采用线栓法制备大脑中动脉局灶性脑缺血(MCAO)模型,共分为假手术组、产前应激+假手术组、MCAO模型组、产前应激+MCAO组(n=10)。于再灌注24 h后进行神经功能评分,并检测脑梗死面积、神经细胞凋亡情况和凋亡相关蛋白表达。结果:产前应激+MCAO组子代大鼠神经功能评分、脑梗死面积百分比、TUNEL阳性细胞、半胱氨酸天冬氨酸蛋白酶3(Caspase3)和活化的Caspase 3蛋白表达均较MCAO组显著增加(P0.05),而B淋巴细胞瘤-2(Bcl-2)蛋白表达较MCAO组减少(P0.05)。结论:产前应激可能通过促进子代大鼠脑缺血/再灌注后神经细胞凋亡,加重神经功能缺损。     

五味子醇甲诱导缺血半影区神经元自噬提高脑卒中后神经保护

五味子醇甲(Schisandra A, Sch A)是五味子中具有生物活性的木脂素化合物,其神经保护作用已在多种神经系统疾病动物模型中得到验证。然而,五味子醇甲是否能通过影响大鼠脑缺血半影区神经元自噬活性对脑缺血再灌注大鼠模型产生神经保护作用,尚缺乏系统研究。为探究Sch A对大鼠脑卒中后神经损伤及缺血半影区神经元自噬活性的影响,本研究将90只SD雄性大鼠随机分为假手术(Sham)组、模型组(MCAO)、Sch A低剂量组(40μg/kg)、Sch A中剂量组(80μg/kg)、Sch A高剂量组(160μg/kg),每组18只。线栓法制备大鼠大脑中动脉梗塞(middle cerebral artery occlusion,MCAO)模型,脑缺血持续90 min后进行再灌注,立即侧脑室给药,1/d,连续给药7 d。各组分别取6只大鼠进行神经功能评分后,取脑进行TTC染色检测脑梗死体积。另有6只大鼠取缺血半影区脑组织,通过Western印迹检测自噬相关蛋白质Beclin1、LC3-Ⅱ的表达水平。剩余6只大鼠脑组织用于免疫荧光双标,对Sch A改变的自噬活性进行细胞表达定位。研究结果显示,MCAO组大鼠脑梗死体积及神经功能损伤评分均显著高于Sham组(P0.05),且Beclin1及LC3-Ⅱ的表达显著增加(P0.05)。各Sch A治疗组大鼠脑梗死体积较未给药组显著减少(P0.05),神经功能损伤得到明显改善(P0.05)。同时,Sch A给药组Beclin1及LC3蛋白质表达水平明显升高(P0.05),且免疫荧光双标显示该自噬活性改变主要呈现于神经元。以上结果表明,Sch A可显著减轻大鼠脑缺血再灌注损伤,该神经保护作用与其提高缺血半影区神经元自噬活性密切相关。     

ATP敏感性钾通道开放剂对脑缺血再灌注损伤的保护作用

目的探讨ATP敏感性钾通道开放剂对大鼠局灶性脑缺血再灌注损伤的保护作用。方法40只Wistar雄性大鼠随机分为四组:A组(假手术组)、B组(缺血组)、C组(KATP开放剂治疗组)及D组(KATP开放剂 阻断剂治疗组)。应用线栓法制备大鼠大脑中动脉缺血模型(MCAO),应用TUNEL法检测神经元凋亡,应用免疫组化方法检测Caspase-3蛋白表达,并观察脑梗死体积及神经功能缺损评分。结果(1)C组脑梗死体积显著小于B、D组(P<0.01),B、D组之间无显著性差异(P>0.05);(2)C组神经功能缺损程度较B、D组显著减轻(P<0.05),B、D组之间无显著性差异(P>0.05);(3)C组神经元凋亡数较B、D组显著减少(P<0.01),B、D组之间无显著性差异(P>0.05);(4)C组Caspase-3蛋白表达显著少于B、D组(P<0.01),B、D组之间无显著性差异(P>0.05)。结论KATP通道开放剂能显著减轻脑缺血再灌注后脑梗死体积、改善神经功能缺损程度、减少Caspase-3蛋白表达、抑制神经元凋亡,对脑缺血再灌注损伤发挥保护作用。     

热休克蛋白A5介导的自噬在小鼠脑缺血/再灌注损伤中的作用

目的：探讨热休克蛋白A5（HSPA5）诱导的自噬在小鼠脑缺血/再灌注损伤中的作用。方法：将36只BALB/c小鼠随机分为sham、缺血再灌注（I/R）、vehicle + I/R、3-甲基腺嘌呤（3-MA） + I/R、scramble siRNA + I/R和HSPA5 siRNA + I/R组（n=6）。Sham组只进行手术操作,不插入线栓。I/R采用大脑中动脉阻塞（MCAO）60 min后再灌注24 h。Vehicle + I/R组和3-MA + I/R将5μl 0.9% NaCl或3-MA （30 mg/ml）在MCAO前30 min侧脑室注射。scramble siRNA + I/R组和HSPA5 siRNA + I/R组将5μl scramble siRNA或HSPA5 siRNA （2μg/μl）在MCAO前24 h侧脑室注射。检测神经细胞内自噬体、缺血大脑皮层（LC3）-Ⅱ/LC3-I表达、神经元损伤程度及神经功能缺损。结果：显微镜下sham组小鼠大脑皮层神经细胞形态正常;I/R组小鼠缺血大脑皮层神经元胞质中细胞器减少,自噬体形成。与sham组比较,I/R组缺血大脑皮层LC3-Ⅱ/LC3-I蛋白表达水平显著增高（P < 0.05）;与I/R组相比,3-MA + I/R组或HSPA5 siRNA + I/R组缺血大脑皮层LC3-Ⅱ/LC3-I蛋白表达明显减少（P < 0.05）;3-MA + I/R组及HSPA5 siR-NA + I/R组I/R后脑缺血性损伤及神经系统症状加重（P < 0.05）。结论：HSPA5诱导自噬可能在小鼠局灶性I/R损伤中发挥保护作用。     

黑木耳多糖对急性脑缺血/再灌注损伤影响的研究

目的:观察黑木耳多糖(APP)对急性脑缺血大鼠的保护作用并探讨其相关机制。方法:成年雄性SD大鼠给予不同浓度的AAP灌胃20d,每天1次,腹腔注射银杏叶提取物(ginkgo biloba extract,EGb671)作为阳性对照,20d后实施右侧大脑中动脉栓塞(MCAO)建立局灶性脑缺血模型。MCAO60min后复灌,复灌24h后进行Longa神经功能损伤评分,并用2,3,5-氯化三苯基四氮唑(TTC)染色法测定脑梗死面积。复灌48h后用TUNEL免疫组化检测神经元凋亡,测定脑组织线粒体内活性氧簇(ROS)的生成量判断氧化应激水平。结果:黑木耳多糖能降低神经功能损伤评分,减小脑梗死面积,减少神经元凋亡,并且能够使缺血复灌脑组织线粒体ROS生成显著减少。高剂量AAP组的凋亡神经元数量、ROS生成量和阳性对照组相比有显著性差异。结论:黑木耳多糖能够对抗大鼠的局灶性脑缺血损伤,其保护作用和减轻氧化应激水平有关,并优于银杏叶提取物。     

毛蕊异黄酮通过抑制calpain-1的表达发挥抗脑缺血再灌注损伤的研究

目的:探讨毛蕊异黄酮抗脑缺血再灌注损伤的作用是否与抑制calpain-1的表达有关。方法:将SD大鼠随机分为假手术组、模型组以及药物组,采用线栓法建立大鼠大脑中动脉阻断(MCAO)模型,于缺血再灌注前30 min腹腔注射给予20 mg/kg毛蕊异黄酮或等体积的溶剂。再灌注24 h后,行神经功能学评分、脑梗死面积以及神经元凋亡检测;再灌注12 h、24 h时,采用免疫组化和蛋白印迹技术检测大鼠脑皮层calpain-1的表达。结果:与假手术组大鼠比较,MCAO模型组大鼠再灌注24 h后神经功能学评分、梗死面积、神经元凋亡率及calpain-1的表达均明显升高(P0.05),而毛蕊异黄酮能够降低模型组大鼠再灌注24 h后神经功能学评分、梗死面积、神经元凋亡率以及calpain-1的表达(P0.05)。结论:毛蕊异黄酮可能通过抑制calpain-1的表达发挥抗脑缺血再灌注损伤作用。     

大鼠局灶性脑缺血后不同时间点磷酸化Rb蛋白与凋亡神经元的共定位研究

目的探讨大鼠局灶性脑缺血后磷酸化Rb蛋白(p-Rb,ser 795)的表达定位与神经元凋亡的时空关系。方法制备大鼠大脑中动脉梗塞(MCAO)模型,分为假手术对照组、缺血1h再灌注12h,1d,3d,7d组。利用TUNEL法检测缺血周边区细胞凋亡情况;TUNEL与p-Rb荧光双标观察神经元凋亡与p-Rb表达、定位的关系。结果缺血半暗带内大部分TUNEL阳性细胞为神经元;大鼠MCAO再灌注12h和1d,TUNEL与p-Rb分别以重叠和镶嵌的方式共定位;再灌注3d,7d发生p-Rb核浆转移的神经元与TUNEL染色细胞仍然分别维持在高水平,但是两者却没有明显的共定位关系。结论 p-Rb可能参与短暂局灶脑缺血后神经元早期凋亡过程,间接或者不参与神经元晚期凋亡过程。     

早期跑步运动对大鼠脑缺血/再灌注损伤后神经行为与神经元凋亡的影响

目的: 探讨早期跑步运动对大鼠脑缺血后神经行为与神经元凋亡的影响。方法:雄性SD大鼠随机分为4组:假手术+安静组(Sham-St、假手术+运动组(Sham-Ex)、缺血(大脑中动脉闭塞(MCAO) +运动组((MCAO -Ex)和缺血+安静组(MCAO-St),每组15只。MCAO-Ex 和 MCAO-St 组大鼠行MCAO 60 min,再灌注2 d后,MCAO-Ex 和Sham-Ex大鼠在跑步机上进行5 d的30 min/d跑步运动(15 m/min),之后进行神经行为学评价,最后大鼠断头取脑进行TTC方法染色,评估各组大鼠梗死体积以及缺血半影Caspase-3和TUNEL阳性细胞表达水平。结果:与Sham-St相比,MCAO-St和MCAO-Ex大鼠缺血半影区Caspase-3表达均显著升高 (P＜0.05);与MCAO-St 组大鼠相比,MCAO-Ex组大鼠脑梗死体积明显减少,大鼠神经功能评分明显改善,大鼠缺血半影区Caspase-3和TUNEL阳性细胞表达水平显著降低 (P＜0.05)。结论: 早期运动可能通过抑制大鼠脑缺血后神经元凋亡发挥神经保护作用。     

雌激素受体GPER通过抑制内质网应激减轻脑缺血再灌注损伤

本文旨在研究G蛋白耦联雌激素受体(G protein-coupled estrogen receptor, GPER)是否通过作用于内质网应激(endoplasmic reticulum stress, ERS)减轻脑缺血再灌注损伤(cerebral ischemia-reperfusion injury, CIRI)中的海马神经元损伤。采用大脑中动脉栓塞法(middle cerebral artery occlusion, MCAO)制备CIRI动物模型。选取雌性去卵巢(ovariectomized, OVX) Sprague-Dawley(SD)大鼠,随机分为4组:对照(Control)组、缺血再灌注损伤(MCAO)组、溶媒(MCAO+DMSO)组、GPER特异性激动剂G1(MCAO+G1)组。用Longa评分法对大鼠进行神经行为学评分,用尼氏染色法观察神经元形态学改变,用TTC染色法检测脑梗死情况,用TUNEL染色法检测海马CA1区神经元凋亡情况,用免疫荧光染色技术观察海马CA1区GRP78 (78 kDa glucoseregulatedprotein78)的分布和表达,用Westernblot检测GRP78、Caspase-12、CHOP和Caspase-3蛋白表达水平,用real-time PCR检测GRP78、Caspase-12、CHOPmRNA水平。结果显示,与对照组相比,MCAO组大鼠神经行为学评分、脑梗死体积、细胞凋亡指数、GRP78、Caspase-12和CHOP蛋白和mRNA表达水平均显著升高。而G1可逆转MCAO组大鼠的上述变化。以上结果提示,激活GPER可减少神经元凋亡,减轻大鼠CIRI,其机制可能涉及GPER对ERS的抑制。     

局部亚低温联合硫酸镁对局灶性脑缺血大鼠的保护作用

目的:探讨联合应用局部亚低温(32-35℃)及硫酸镁对局灶性脑缺血大鼠的保护作用及其可能机制。方法:通过线栓法建立大鼠大脑中动脉阻塞(MCAO)模型,将40只雄性Wistar大鼠随机分为假手术组、常温组、亚低温组、硫酸镁组、亚低温+硫酸镁组,每组8例,采用Longa神经功能评分、TTC染色、TUNEL技术,检测和比较各组脑缺血后大鼠的神经功能、脑梗死体积、凋亡细胞数。结果:与常温组相比,亚低温组与亚低温+硫酸镁组的梗死体积、神经功能评分、凋亡细胞数均明显降低,差异有显著意义(P0.05);而与亚低温组相比,亚低温+硫酸镁组局灶脑缺血大鼠的脑梗死体积、神经功能评分、凋亡细胞数均显著减少,差异有显著意义(P0.05)。结论:与单独应用亚低温相比,局部亚低温与硫酸镁联合应用,对局灶性脑缺血大鼠可发挥更有效的脑保护作用,其机制可能与抑制脑缺血后凋亡有关。     

Ginkgo biloba extract (EGb 761) prevents the ischemic brain injury-induced decrease in parvalbumin expression

Ginkgo biloba extract (EGb 761) exerts a neuroprotective effect against ischemic brain injury through an anti-apoptotic mechanism. Parvalbumin is a calcium buffering protein that plays an important role in modulating intracellular calcium concentration and regulating apoptotic cell death. The aim of this study was to investigate whether EGb 761 affects parvalbumin expression in cerebral ischemic injury. Adult male Sprague-Dawley rats were treated with vehicle or EGb 761 (100 mg/kg) prior to middle cerebral artery occlusion (MCAO) and cerebral cortex tissues were collected 24 h after MCAO. A proteomic approach revealed a reduction in parvalbumin expression in the vehicle-treated animals, whereas EGb 761 pretreatment attenuates the ischemic injury-induced decrease in parvalbumin expression. RT-PCR and Western blot analyses clearly confirmed the fact that EGb 761 prevents the injury-induced decrease in parvalbumin. Moreover, the results of immunohistochemical staining showed that the number of parvalbumin-positive cells was lower in vehicle-treated animals than in sham-operated animals, and EGb 761 averted this decrease. Thus, these results suggest that the maintenance of parvalbumin expression is associated with the neuroprotective function of EGb 761 against neuronal damage induced by ischemia.     

Kaempferol Mediated AMPK/mTOR Signal Pathway Has a Protective Effect on Cerebral Ischemic-Reperfusion Injury in Rats by Inducing Autophagy

Ischemia/reperfusion (I/R) caused by ischemic stroke treatments leads to brain injury and its pathological mechanism is related to autophagy. The underlying mechanism of kaempferol on cerebral I/R injury needs to be explored. To establish I/R injury, we used a middle cerebral artery occlusion-reperfusion (MCAO) model in rats. MCAO rats were treated with the same amount of saline (I/R group); Treatment group rats were treated orally with kaempferol (50, 100, 200 mg/kg) for 7 days before surgery. After reperfusion for 24 h, the scores of neurological deficits and infarct volume in each group were evaluated. LC3, Beclin-1 p62, AMPK and mTOR protein expression levels were examined by TTC staining, immunofluorescence staining, qRT-PCR and western blotting assay. H&E and TTC staining showed that compared with model group, the infarction size of rats in kaempferol group was markedly reduced. Meanwhile, the results showed that kaempferol had a dose-dependent nerve function repairability. Nissl and TUNEL staining showed that kaempferol could reduce neuronal apoptosis and ameliorate neuronal impairment after I/R. Western blotting and qRT-PCR results showed that kaempferol could protect the brain from ischemia reperfusion by activating autophagy. In addition, add AMPK inhibitor, western blotting and immumohistochemical staining showed that kaempferol mediated AMPK/mTOR signal pathway in MCAO rats. Kaempferol could mediate the AMPK signal pathway to regulate autophagy and inhibit apoptosis to protect brain against I/R injury.

     

Effects of Treadmill Exercise on Motor and Cognitive Function Recovery of MCAO Mice Through the Caveolin-1/VEGF Signaling Pathway in Ischemic Penumbra

Exercise has been regarded as an effective rehabilitation strategy to facilitate motor and cognitive functional recovery after stroke, even though the complex effects associated with exercise-induced repair of cerebral ischemic injury are not fully elucidated. The enhancement of angiogenesis and neurogenesis, and the improvement of synaptic plasticity following moderate exercise are conducive to functional recovery after ischemic damage. Our previous studies have confirmed the angiogenesis and neurogenesis through the caveolin-1/VEGF pathway in MCAO rats. As an essential neurotrophic factor, BDNF has multiple effects on ischemic injury. In this study, we attempted to determine an additional mechanism of treadmill exercise-mediated motor and cognitive functional recovery through the caveolin-1/VEGF pathway associated with BDNF in the ischemic penumbra of MCAO mice. We found that mice exposed to treadmill exercise after the MCAO operation showed a significant up-regulation in expression of caveolin-1, VEGF, BDNF, synapsin I and CYFIP1 proteins, numbers of cells positive for BrdU/CD34, BDNF, BrdU/NeuN, BrdU/Synapsin I and CYFIP1 expression were increased, which support the reduction in neurological deficit and infarction volume, as well as improved synaptic morphology and spatial learning abilities, compared with the non-exercise mice. However, the caveolin-1 inhibitor, daidzein, resulted in increase in neurological deficit and infarction volume. The selective VEGFR2 inhibitor, PD173074, significantly induced larger infarction volume and neurological injury, and decreased the expression of BDNF in the ischemic penumbra. These findings indicate that exercise improves angiogenesis, neurogenesis and synaptic plasticity to ameliorate motor and cognitive impairment after stroke partially through the caveolin-1/VEGF pathway, which is associated with the coregulator factor, BDNF.

     

Neuronal injury in rat model of permanent focal cerebral ischemia is associated with activation of autophagic and lysosomal pathways

It has been reported that ischemic insult increases the formation of autophagosomes and activates autophagy. However, the role of autophagy in ischemic neuronal damage remains elusive. This study was taken to assess the role of autophagy in ischemic brain damage. Focal cerebral ischemia was introduced by permanent middle cerebral artery occlusion (pMCAO). Activation of autophagy was assessed by morphological and biochemical examinations. To determine the contribution of autophagy/lysosome to ischemic neuronal death, rats were pretreated with a single intracerebral ventricle injection of the autophagy inhibitors 3-methyl-adenine (3-MA) and bafliomycin A1 (BFA) or the cathepsin B inhibitor Z-FA-fmk after pMCAO. The effects of 3-MA and Z-FA-fmk on brain damage, expression of proteins involved in regulation of autophagy and apoptosis were assessed with 2,3,5-triphenyltetrazolium chloride (TTC) staining and immunoblotting. The results showed that pMACO increased the formation of autophagosomes and autolysosomes, the mRNA and protein levels of LC3-II and the protein levels of cathepsin B. 3-MA, BFA and Z-FA-fmk significantly reduced infarct volume, brain edema, and motor deficits. The neuroprotective effects of 3-MA and Z-FA-fmk were associated with an inhibition on ischemia-induced upregulation of LC3-II and cathepsin B and a partial reversion of ischemia-induced downregulation of cytoprotective Bcl-2. These results demonstrate that ischemic insult activates autophagy and an autophagic mechanism may contribute to ischemic neuronal injury. Thus, autophagy may be a potential target for developing a novel therapy for stroke.     

Neuronal injury in rat model of permanent focal cerebral ischemia is associated with activation of autophagic and lysosomal pathways

It has been reported that ischemic insult increases the formation of autophagosomes and activates autophagy. However, the role of autophagy in ischemic neuronal damage remains elusive. This study was taken to assess the role of autophagy in ischemic brain damage. Focal cerebral ischemia was introduced by permanent middle cerebral artery occlusion (pMCAO). Activation of autophagy was assessed by morphological and biochemical examinations. To determine the contribution of autophagy/lysosome to ischemic neuronal death, rats were pretreated with a single intracerebral ventricle injection of the autophagy inhibitors 3-methyl-adenine (3-MA) and bafliomycin A1 (BFA) or the cathepsin B inhibitor Z-FA-fmk after pMCAO. The effects of 3-MA and Z-FA-fmk on brain damage, expression of proteins involved in regulation of autophagy and apoptosis were assessed with 2,3,5-triphenyltetrazolium chloride (TTC) staining and immunoblotting. The results showed that pMACO increased the formation of autophagosomes and autolysosomes, the mRNA and protein levels of LC3-II and the protein levels of cathepsin B. 3-MA, BFA and Z-FA-fmk significantly reduced infarct volume, brain edema and motor deficits. The neuroprotective effects of 3-MA and Z-FA-fmk were associated with an inhibition on ischemia-induced upregulation of LC3-II and cathepsin B and a partial reversion of ischemia-induced downregulation of cytoprotective Bcl-2. These results demonstrate that ischemic insult activates autophagy and an autophagic mechanism may contribute to ischemic neuronal injury. Thus, autophagy may be a potential target for developing a novel therapy for stroke.     

原花青素对脑缺血再灌损伤大鼠模型的影响

目的研究原花青素对脑缺血/再灌损伤(ischemia/reperfusion,I/R)大鼠神经功能评分(neurologicaldeficit score,NDS)、脑梗死体积、脑含水量等指标的药理作用。方法采用大鼠大脑中动脉阻断(middle cerebralartery occlusion,MCAO)法复制类似人类缺血性卒中的I/R损伤模型。结果该模型各时间点内均有程度不同的神经功能缺失,原花青素给药组神经功能评分明显低于对照组(P0.05),假手术组大鼠均无神经功能缺失,脑水肿情况均较对照组明显改善(P0.05),脑梗死体积与盐水对照组相比差异有显著性(P0.05),而假手术组均未见有梗死灶。结论原花青素具有一定的保护大鼠I/R后受损脑组织的作用,可供后续研究,并可为缺血性卒中使用原花青素治疗提供确凿的理论依据。     

Delayed Administration of Parecoxib, a Specific COX-2 Inhibitor, Attenuated Postischemic Neuronal Apoptosis by Phosphorylation Akt and GSK-3β

Parecoxib is a recently described novel COX-2 inhibitor whose functional significance and neuroprotective mechanisms remain elusive. Therefore, in this study, we aimed to investigate whether delayed administration of parecoxib inhibited mitochondria-mediated neuronal apoptosis induced by ischemic reperfusion injury via phosphorylating Akt and its downstream target protein, glycogen synthase kinase 3β (GSK-3β). Adult male Sprague–Dawley rats were administered parecoxib (10 or 30 mg kg⁻¹, IP) or isotonic saline twice a day starting 24 h after middle cerebral artery occlusion (MCAO) for three consecutive days. Cerebral infarct volume, apoptotic neuron, caspase-3 immunoreactivity and the protein expression of p-Akt, p-GSK-3β and Cytochrome C in cerebral ischemic cortex were evaluated at 96 h after reperfusion. Parecoxib significantly diminished infarct volume and attenuated neuron apoptosis in a dose-independent manner, compared with MCAO group alone. Increased p-Akt and p-GSK-3β was observed in the ischemic penumbra of parecoxib group after stroke. Moreover, parecoxib also reduced the release of Cytochrome C from mitochondrial into cytosol and attenuated the caspase-3 immunoreactivity in the penumbra. Taken together, these results suggested that parecoxib ameliorated postischemic mitochondria-mediated neuronal apoptosis induced by focal cerebral ischemia in rats and this neuroprotective potential is involved in phosphorylation of Akt and GSK-3β.     

Vagus Nerve Stimulation Attenuates Cerebral Ischemia and Reperfusion Injury via Endogenous Cholinergic Pathway in Rat

Inflammation and apoptosis play critical roles in the acute progression of ischemic injury pathology. Emerging evidence indicates that vagus nerve stimulation (VNS) following focal cerebral ischemia and reperfusion (I/R) may be neuroprotective by limiting infarct size. However, the underlying molecular mechanisms remain unclear. In this study, we investigated whether the protective effects of VNS in acute cerebral I/R injury were associated with anti-inflammatory and anti-apoptotic processes. Male Sprague-Dawley (SD) rats underwent VNS at 30 min after focal cerebral I/R surgery. Twenty-four h after reperfusion, neurological deficit scores, infarct volume, and neuronal apoptosis were evaluated. In addition, the levels of pro-inflammatory cytokines were detected using enzyme-linked immune sorbent assay (ELISA), and immunofluorescence staining for the endogenous “cholinergic anti-inflammatory pathway” was also performed. The protein expression of a7 nicotinic acetylcholine receptor (a7nAchR), phosphorylated Akt (p-Akt), and cleaved caspase 3 in ischemic penumbra were determined with Western blot analysis. I/R rats treated with VNS (I/R+VNS) had significantly better neurological deficit scores, reduced cerebral infarct volume, and decreased number of TdT mediated dUTP nick end labeling (TUNEL) positive cells. Furthermore, in the ischemic penumbra of the I/R+VNS group, the levels of pro-inflammatory cytokines and cleaved caspase 3 protein were significantly decreased, and the levels of a7nAchR and phosphorylated Akt were significantly increased relative to the I/R alone group. These results indicate that VNS is neuroprotective in acute cerebral I/R injury by suppressing inflammation and apoptosis via activation of cholinergic and a7nAchR/Akt pathways.     

Role of acute-phase protein ORM in a mice model of ischemic stroke

The only Food and Drug Administration-approved treatment for acute ischemic stroke is tissue plasminogen activator, and the discovery of novel therapeutic targets is critical. Here, we found orosomucoid (ORM), an acute-phase protein mainly produced by the liver, might act as a treatment candidate for an ischemic stroke. The results showed that ORM2 is the dominant subtype in mice normal brain tissue. After middle cerebral artery occlusion (MCAO), the level of ORM2 is significantly increased in the ischemic penumbra compared with the contralateral normal brain tissue, whereas ORM1 knockout did not affect the infarct size. Exogenous ORM could significantly decrease infarct size and neurological deficit score. Inspiringly, the best administration time point was at 4.5 and 6 hr after MCAO. ORM could markedly decrease the Evans blue extravasation, and improve blood–brain barrier-associated proteins expression in the ischemic penumbra of MACO mice and oxygen–glucose deprivation (OGD)-treated bEnd3 cells. Meanwhile, ORM could significantly alleviate inflammation by inhibiting the production of interleukin 1β (IL-1β), IL-6, and tumor necrosis factor α (TNF-α), reduce oxidative stress by improving the balance of malondialdehyde (MDA) and superoxide dismutase (SOD), inhibit apoptosis by decreasing caspase-3 activity in ischemic penumbra of MCAO mice and OGD-treated bEnd.3 cells. Because of its protective role at multiple levels, ORM might be a promising therapeutic target for ischemic stroke.