Time-course pattern of neuronal loss and gliosis in gerbil hippocampi following mild, severe, or lethal transient global cerebral ischemia

Transient ischemia in the whole brain leads to neuronal loss/death in vulnerable brain regions. The striatum, neocortex and hippocampus selectively loose specific neurons after transient ischemia. Just 5 minutes of transient ischemia can cause pyramidal neuronal death in the hippocampal cornu ammonis (CA) 1 field at 4 days after transient ischemia. In this study, we investigated the effects of 5-minute (mild), 15-minute (severe), and 20-minute (lethal) transient ischemia by bilateral common carotid artery occlusion (BCCAO) on behavioral change and neuronal death and gliosis (astrocytosis and microgliosis) in gerbil hippocampal subregions (CA1-3 region and dentate gyrus). We performed spontaneous motor activity test to evaluate gerbil locomotor activity, cresyl violet staining to detect cellular distribution, neuronal nuclei immunohistochemistry to detect neuronal distribution, and Fluoro-Jade B histofluorescence to evaluate neuronal death. We also conducted immunohistochemical staining for glial fibrillary acidic protein and ionized calcium-binding adapter molecule 1 (Ibal) to evaluate astrocytosis and microgliosis, respectively. Animals subjected to 20-minute BCCAO died in at least 2 days. BCCAO for 15 minutes led to pyramidal cell death in hippocampal CA1-3 region 2 days later and granule cell death in hippocampal de匚tate gyrus 5 days later. Similar results were not found in animals subjected to 5-minute BCCAO. Gliosis was much more rapidly and severely progressed in animals subjected to 15-minute BCCAO than in those subjected to 5- minute BCCAO. Our results indicate that neuronal loss in the hippocampal formation following transient ischemia is significantly different according to regions and severity of transient ischemia. The experimental protocol was approved by Institutional Animal Care and Use Committee (AICUC) of Kangwon National University (approval No. KW-180124-1) on May 22, 2018.

Pretreated Oenan the Javanica extract increases anti-inflammatory cytokines, attenuates gliosis, and protects hippocampal neurons following transient global cerebral ischemia in gerbils

Recently,we have reported that Oenanthe javanica extract(OJE)displays strong neuroprotective effect against ischemic damage after transient global cerebral ischemia.However,neuroprotective mechanisms of OJE have not been fully identified.Thus,this study investigated the neuroprotection of OJE in the hippocampal CA1 area and its anti-inflammatory activity in gerbils subjected to 5 minutes of transient global cerebral ischemia.We treated the animals by intragastrical injection of OJE(100 and 200 mg/kg)once daily for 1 week prior to transient global cerebral ischemia.Neuroprotection of OJE was observed by immunohistochemistry for neuronal nuclear antigen and histofluorescence staining for Fluoro-Jade B.Immunohistochemistry of glial fibrillary acidic protein and ionized calcium-binding adapter molecule 1 was done for astrocytosis and microgliosis,respectively.To investigate the neuroprotective mechanisms of OJE,we performed immunohistochemistry of tumor necrosis factor-alpha and interleukin-2 for pro-inflammatory function and interleukin-4 and interleukin-13 for anti-inflammatory function.When we treated the animals by intragastrical administration of 200 mg/kg of OJE,hippocampal CA1 pyramidal neurons were protected from transient global cerebral ischemia and cerebral ischemia-induced gliosis was inhibited in the ischemic hippocampal CA1 area.We also found that interleukin-4 and-13 immunoreactivities were significantly increased in pyramidal neurons of the ischemic CA1 area after OJE pretreatment,and the increased immunoreactivities were sustained in the CA1 pyramidal neurons after transient global cerebral ischemia.However,OJE pretreatment did not increase interleukin-2 and tumor necrosis factor-alpha immunoreactivities in the CA1 pyramidal neurons.Our findings suggest that pretreatment with OJE can protect neurons and attenuate gliosis from transient global cerebral ischemia via increasing expressions of interleukin-4 and-13.The experimental plan of this study was reviewed and approved by the Institutional Animal Care and Use Committee(IACUC)in Kangwon National University(approval No.KW-160802-1)on August 10,2016.

Nerve growth factor downregulates c-jun mRNA and Caspase-3 in striate cortex of rats after transient global cerebral ischemia/reperfusion

BACKGROUND： Immediate early gene （lEG） c-jun is a sensitive marker for functional status of nerve cells. Caspase-3 is a cysteine protease, which is a critical regulator of apoptosis. The effect of exogenous nerve growth factor （NGF） on the expression of c-jun mRNA and Caspase-3 protein in striate cortex of rats with transient global cerebral ischemia/reperfusion （IR） is unclear. OBJECTIVE： To study the protective effect of exogenous NGF on the brain of rats with transient globa cerebral IR and its effecting pathway by observing the expression of c-jun mRNA and Caspase-3 protein. DESIGN： Randomized controlled animal trial SETTING： Department of Neural Anatomy, Institute of Brain, China Medical University MATERIALS：Eighteen healthy male SD rats of clean grade, aged 1 to 3 months, with body mass of 250 to 300 g, were involved in this study. NGF was provided by Dalian Svate Pharmaceutical Co.,Ltd. c-jun in situ hybridization detection kit, Caspase-3 antibody and SABC kit were purchased from Boster Biotechnology Co.. Ltd. METHODS： This trial was carried out in the Department of Neural Anatomy, Institute of Brain, China Medical University during September 2003 to April 2005. （1） Experimental animals were randomized into three groups with 6 in each： sham-operation group, IR group and NGF group.（2）After the rats were anesthetized, the bilateral common carotid arteries and right external carotid arteries of rats were bluntly dissected and bilateral common carotid arteries were clamped for 30 minutes with bulldog clamps. Reperfusion began after buldog clamps were removed. Normal saline of lmL and NGF （1×10^6 U/L） of 1 mL was injected into the common carotid artery of rats via right external carotid arteries in the IR group and NGF group respectively. The injection was conducted within 30 minutes, and then the right external carotid arteries were ligated. In the sham-operation group, occlusion of bilateral common carotid arteries and administration of drugs were omitted.GAll the rats were executed by decollation at 3 hours after modeling. The animals were fixed with phosphate buffer solution （PBS, 0.1 mol/L） containing 40 g/L polyformaldehyde, their brains were quickly removed. The coronal section tissue mass containing striate cortex about 3 mm before line between two ears was taken and made into successive frozen sections.（4）The expression of c-jun mRNA and Caspase-3 protein in striate cortex of global cerebral ischemia rats were detected with in situ hybridization, immunohistochemistry and microscope image analysis. （5）t test was used for comparing the difference of the measurement data. MAIN OUTCOME MEASURES：Comparison of the expression of lEG c-jun mRNA and Caspase-3 protein in striate cortex of brain of rats in each group. RESULTS：All the 18 SD rats were involved in the analysis of results. The c-jun mRNA and Caspase-3 protein positive reaction cells were found brown yellow in the striate cortex of rats, and most of them were in lamellas Ⅱ and Ⅲ, mainly presenting round or oval. The expression of c-jun mRNA and Caspase-3 protein in sham-operation group was weak or negative. The average gray value of c-jun mRNA and Caspase-3 protein in the IR group was significantly lower than that in the sham-operation group （49.52±4.13 vs. 95.48± 5.28; 74.73±4.29 vs. 162.38±9.16,P 〈 0.01）. The average gray value of c-jun mRNA and Caspase-3 protein in the NGF group was significantly higher than that in the IR group （63.96±4.25 vs.49.52±4.13; 83.98± 4.13 vs. 74.73±4.29, P〈 0.05）. CONCLUSION： NGF can protect ischemic neurons by down-regulating the expression of c-jun mRNA and Caspase-3 protein in striate cortex of global cerebral ischemia rats.

Effect of Chinese Patent Medicine Naodesheng against Repeated Transient Global Cerebral Ischemia in Mice

Objective To investigate the therapeutic effect and possible mechanisms of Chinese ptent medicine Naodesheng（NDS） on repeated transient global cerebral ischemia（GCI） in mice. Methods The repeated transient GCI mice were induced by bilateral carotid arteries ligation, and were randomly divided into model group, Sham group without arteries ligation, NDS groups（1.25 and 2.5 g/kg） and positive control（vinpocetine 3.1 mg/kg, VP） group. After oral administration once daily for successive 7 d, the transient GCI was induced. The degree of neurological deficit, histological changes, and neurons loss in the hippocampus were evaluated. In order to investigate the possible mechanisms, the oxidative stress and inflammatory factor were measured after 24 h of GCI. Comparison among multiple groups was performed with one-way analysis of variance（ANOVA）. Results NDS could significantly alleviate the neurological function impairment, histological injury, and neurons loss, increase the superoxide dismutase（SOD） activity, decrease the content of malondialdehyde（MDA）, and reduce inflammatory factor in the ischemic brain tissue. Conclusion NDS could significantly reduce brain injury induced by global ischemia, and its mechanism is closely associated with anti-oxidation and anti-inflammation.

NVP-AAM077和Ro25-6981对全脑缺血小鼠海马神经元损伤及BDNF表达的影响

目的探讨N-甲基-D-天冬氨酸受体(NMDA)亚基NR2A和NR2B特异性拮抗剂对脑缺血/再灌注后海马CA1区神经元损伤的不同影响及其可能机制。方法制作三动脉阻断(3-VO)小鼠全脑缺血模型,小鼠随机分为假手术组、脑缺血/再灌注(I/R)对照组、NVP-AAM077(NVP)干预组和Ro25-6981(Ro)干预组;应用Fluoro-JadeB(F-JB)和Nissl染色检测海马神经元变性死亡和存活情况,Western blot对脑源性神经生长因子(BDNF)蛋白表达水平进行定量分析。结果①小鼠全脑缺血12min/再灌注3d后,海马CA1区出现选择性迟发性神经元死亡,NVP干预组增加了缺血所致的海马神经元死亡(P<0.05),而Ro干预组CA1区神经元存活数量明显多于缺血/再灌注组(P<0.01);②NVP干预能明显下调缺血/再灌注所致的海马组织BDNF蛋白表达升高(P<0.01),而Ro干预能明显上调BDNF蛋白的表达(P<0.05)。结论 NMDA受体亚基NR2A和NR2B在小鼠脑缺血/再灌注损伤中具有不同的作用,其机制可能与调节BDNF表达改变有关。

短暂性全面遗忘症患者的病因及临床探讨

目的 探讨短暂性全面遗忘症患者的病因及临床特点。方法 对10例确诊为短暂性全面遗忘症的患者进行24 h内的脑电图、经颅多普勒超声、单光子发射计算机扫描(SPECT)、脑磁共振成像检查。结果 10例短暂性全面遗忘症患者的脑电图均正常,而经颅多普勒超声检查提示椎基底动脉供血异常,SPECT显示不同脑区有低灌注情况。结论 短暂性全面遗忘症患者均有不同程度脑缺血,提示本病病因与脑关键部位缺血有关。

老年人短暂性全面遗忘症的临床特点及病因探讨

目的 探讨老年人短暂性全面遗忘症(TGA)的病因。方法 汇总我院2002～2012年间共24例TGA患者的CT、MRI、血管超声、脑电图等检查资料,结合国内外相关的研究进展探讨老年TGA的病因。结果 75%的TGA患者头颅影像学有缺血性改变,50%的患者血管超声示血管狭窄或动脉斑块,33%的患者伴有糖尿病、房颤等微血栓危险因素;8例发病前有争吵、爬山、骑车、劳动等导致氧耗量增加的因素,1例伴有偏头痛。结论 TGA是一种多病因疾病,但缺血仍是老年TGA的主要病因。

全脑缺血再灌注后海马EphA受体基因表达的变化特点

目的:观察EphA受体在海马全脑缺血再灌注后基因表达的改变。方法:SD大鼠50只随机分为假手术组10只及全脑缺血再灌注组40只,Pulsinelli四血管阻断法建立全脑缺血再灌注模型,采用半定量RT-PCR观察假手术组及缺血组在缺血后不同时间点(6 h、1 d、3 d、7d)EphA受体m RNA含量变化的情况,免疫荧光双标法检测EphA4受体在海马的细胞定位。结果:EphA1-A8及EphA10 RNA在正常海马组织均有表达,EphA4受体含量多。在缺血状态下,EphA1、EphA2、EphA3、EphA6、EphA7及EphA8的mRNA表达水平一过性上调,EphA4、EphA5和EphA10的m RNA表达水平逐步上调;EphA4受体亦是缺血后变化最显著的EphA受体。免疫荧光双标显示EphA4主要分布于海马CA1-CA3区及DG区Neu N阳性锥体神经元。结论:在海马不同的EphA受体对缺血呈现出不同的应答模式,EphA4是海马正常条件下表达最为丰富的EphA受体并且在缺血条件下出现最为显著地表达变化。EphA4受体主要分布于海马CA1-CA3区以及DG区NeuN阳性锥体神经元。

海洋硫酸多糖药物“989”对大鼠脑缺血再灌注的影响

采用栓线法和四动脉结扎法造成大鼠脑缺血再灌注模型 ,观察了海洋硫酸多糖类药物“989”对缺血脑组织的保护作用。结果发现 ,“989”在 2～ 10 mg·kg-1范围内静脉注射 ,能明显缩小脑栓塞大鼠 2 4 h的脑梗塞范围 ,改善行为障碍 ,对局灶性脑缺血和全脑缺血均有明显治疗作用。进一步研究发现 ,其作用机制可能与抑制脑组织 TNF- α表达有关。

短暂性全面遗忘症患者15例临床资料分析

目的分析短暂性全面遗忘症患者的危险因素、病因、鉴别及治疗。方法收集15例临床确诊的短暂性全面遗忘症患者的临床资料,针对症状学、发病危险因素、辅助检查、鉴别诊断及治疗方案进行分析。结果 15例短暂性全面遗忘症患者辅助检查提示脑血管处于缺血状态,经改善循环、营养神经、抗血小板等治疗,治疗有效且随访半年未见复发。结论短暂性全面遗忘症发病很可能与脑缺血有关,按缺血性脑血管病治疗可取得较好效果,并能有效预防疾病复发。

腺苷酸环化酶介导电针预治疗对离体缺血心肌细胞的保护作用

目的:观察电针预治疗对模拟全心缺血心肌细胞的保护作用,并探讨β-AR信号转导站点中腺苷酸环化酶(adenylyl cyclase,AC)介导上述针刺保护效应中的作用。方法:采用离体心脏模拟全心缺血(低灌流)模型,观察正常对照(NC)组、缺血再灌注(IR)组和缺血再灌注+电针(EA)组心肌细胞存活率,心肌细胞内静息钙水平([Ca2+]i)以及各组心肌细胞在Forskolin作用下钙瞬变的变化。结果:EA组心肌细胞存活率明显高于IR组(P<0.01),其心肌[Ca2+]i明显低于IR组(P<0.01),且EA组缺血心肌细胞在Forskolin作用下钙瞬变增加的波幅与相应的IR组比较明显降低(P<0.01)。结论:电针预治疗可以有效地提高缺血心肌细胞的存活率,改善缺血心肌细胞内钙超载情况,抑制缺血引起的AC活性过度增加。

短暂性全面遗忘症7例临床分析

[背景]探讨短暂性全面性遗忘症(TGA)的病因及临床特点.[病例报告]给7例诊断为TGA的患者行脑电图、头颅CT或MRI及颈部血管彩色多普勒超声波检查.7例中合并高血压5例,血脂异常4例,血糖异常1例,颈部动脉粥样斑块形成5例.脑电图检查结果显示,4例未见异常,3例可见少量慢波;头颅CT或MRI检查结果显示,5例腔隙性脑梗塞,2例未见异常.[讨论]TGA患者均有不同程度脑缺血改变,认为TGA发作可能与脑缺血有关联.

钾通道Kv4.2、Kv1.4在硫化氢后处理对大鼠短暂全脑缺血神经保护中的作用研究

目的研究硫氢化钠(sodium hydrosulfide,Na HS)后处理对短暂全脑缺血大鼠海马中钾通道Kv4.2和Kv1.4 mRNA表达变化的影响及其脑保护作用,从而探讨Na HS对大鼠短暂全脑缺血神经保护作用的机制。方法用4VO方法建立大鼠短暂性全脑缺血(transient global cerebral ischemia,t GCI)模型,大鼠被随机分配到3组,分别为:假手术组(sham)、t GCI组、Na HS后处理组。Na HS后处理组为t GCI之后1 d,给予大鼠腹腔注射Na HS 24μmmol/kg或者180μmmol/kg。通过尼氏染色与Neu N免疫染色确定海马神经元的死亡,通过RT-PCR方法检测海马组织Kv4.2和Kv1.4mRNA水平的表达变化。结果 (1)与t GCI组比较,在t GCI之后1 d给予24μmol/kg Na HS后处理使海马CA1区存活细胞数目显著增加,而高剂量的Na HS(180μmol/kg)后处理对t GCI大鼠海马CA1区则无明显的保护作用。(2)在Re 26 h和Re 48 h,海马组织中Kv4.2、Kv1.4的mRNA表达水平均明显低于假手术组(P<0.05)。在Re 26 h+Na HS组,kv4.2(1.24±0.08)和kv1.4(1.11±0.07)的mRNA表达水平均分别高于Re 26 h组的kv4.2(0.75±0.04)和kv1.4(0.79±0.06),差异均有显著性(P<0.05)。结论外源性Na HS可能通过上调大鼠t GCI后海马区Kv4.2和Kv1.4 mRNA的表达,从而导致膜电位超极化,降低神经元兴奋性和氧耗,继而保护神经元免受脑缺血损伤。

大鼠脑缺血再灌注损伤后脑皮层神经突起生长素(neuritin)表达变化的研究

本研究旨在探讨大鼠短暂性脑缺血损伤后不同时间点脑皮层中神经突起生长因子(neuritin)表达的变化规律,为研究neuritin在神经修复中的作用奠定基础数据。采用夹闭双侧颈总动脉的方法制作TGI大鼠模型,按伤后不同时间分为3、7、14、21d组,用免疫印迹及定量PCR的方法检测大鼠脑皮层neuritin蛋白质及mRNA的表达,并分析其表达变化特点。免疫印迹结果显示:3d、21d实验组皮层neuritin的表达与对照组相比无明显变化;7d和14d实验组Neuritin蛋白表达量,显著高于3、21d和对照组。Neuritin mRNA定量PCR结果表明:与对照组相比,各实验组无明显变化。基于Neuritin mRNA和蛋白质的表达特点,推测可能通过某种转录后调控机制调控Neuritin蛋白表达的变化。TGI后,机体启动神经修复机制,Neuritin蛋白表达迅速升高,并维持两周较高水平的表达。当修复完成后Neuritin又恢复到正常水平。这种变化规律提示neuritin在神经损伤中可能具有重要的修复作用。

针刺对短暂性全脑缺血再灌注大鼠自噬相关蛋白的影响

目的:探讨针刺“百会”“大椎”穴对短暂性全脑缺血再灌注大鼠脑组织自噬相关蛋白的影响及作用机制。方法:将54只雄性SD大鼠(200~300 g)随机分为模型组、非穴位组及针刺组各18只。应用改良三血管闭塞法制备短暂性全脑缺血再灌注(transient global cerebral ischemia reperfusion,TGCIR)大鼠模型,针刺组及非穴位组分别针刺百会穴、大椎穴及两穴平行线旁开1 cm非穴位处,每天2次,共3天,治疗3天对大鼠进行神经功能缺损评分,检测大鼠患侧海马CA1(hippocampal,CA1)区脑组织自噬相关蛋白微管连接蛋白轻链3(microtubule-associated protein light chain 3,LC3)及苄氯素1(Beclin 1)表达。结果:与模型组比较,非穴位组在神经功能评分及自噬相关蛋白表达方面均无明显差异(P>0.05);与模型组、非穴位组比较,针刺百会、大椎穴能改善大鼠神经功能评分(P<0.05),上调LC3、Beclin 1蛋白表达(P<0.05)。结论:针刺百会、大椎穴能够上调短暂性全脑缺血再灌注大鼠自噬相关蛋白LC3、Beclin 1表达,进而改善脑损伤大鼠神经功能缺损。

不同浓度七氟醚预处理对tGCI大鼠模型海马组织神经细胞的影响

目的探讨不同浓度七氟醚预处理对短暂性全脑缺血(tGCI)大鼠海马组织神经细胞的影响。方法选取成年健康WKY大鼠48只,将所有WKY大鼠随机分为模型组、2%七氟醚预处理组、4%七氟醚预处理组和6%七氟醚预处理组,各组大鼠均建立tGCI大鼠模型,其中2%七氟醚预处理组、4%七氟醚预处理组和6%七氟醚预处理组分别给予浓度2%、4%和6%七氟醚处理,模型组给予等量生理盐水,HE染色观察各组海马组织,MTT比色法测定海马神经元活性,流式细胞仪检查海马神经细胞凋亡率,Westernblot检查Bax、LC3-Ⅱ蛋白、Bcl-2表达。结果模型组海马神经元结构及排列紊乱,细胞水肿,成片神经元系统核皱缩,七氟醚预处理组海马结构有所改善,其中6%七氟醚预处理组改善明显。七氟醚预处理组海马组织神经元活力OD值明显高于模型组(P<0.05),其中6%七氟醚预处理组海马神经元活力OD值为(1.55±0.26),高于2%七氟醚预处理组和4%七氟醚预处理组(P<0.05);七氟醚预处理组海马组织神经细胞凋亡率明显低于模型组(P<0.05),其中6%七氟醚预处理组海马神经细胞凋亡率为(12.24±3.11)%,低于2%七氟醚预处理组和4%七氟醚预处理组(P<0.05);七氟醚预处理组海马组织Bax蛋白相对表达量明显低于模型组(P<0.05),而Bcl-2、LC3-Ⅱ相对表达量明显高于模型组(P<0.05)。结论七氟醚预处理对tGCI大鼠模型海马组织神经细胞有保护作用,呈剂量依赖性,可能与调控Bax、LC3-Ⅱ和Bcl-2表达有关。

JAK2/STAT3通路参与低氧后处理对成年大鼠短暂全脑缺血神经保护作用的研究

目的探究JAK2/STAT3通路参与低氧后处理对成年大鼠短暂全脑缺血神经保护作用。方法建立60只成年雄性Wistar大鼠短暂全脑缺血再灌注的模型,分为假手术组、缺血组(短暂全脑缺血10 min)和缺血+低氧后处理组[短暂全脑缺血10 min后1 d,给予低氧后处理(8%O2+92%N2)2 h]各20只。采用免疫蛋白印迹法等方法观察缺血组、后处理+缺血组在不同再灌注时间点磷酸化JAK2(P-JAK2)、磷酸化STAT3(P-STAT3)在大脑皮层、海马区的表达变化。结果与缺血组相比较,缺血+低氧后处理组神经功能缺损评分明显更低,差异有统计学意义(P<0.05)。缺血+低氧后处理组顶叶皮层神经元形态基本正常,其余各组都有不同程度的神经元变性表现,缺血组神经元变性程度最严重缺血组Tunnel染色计数阳性细胞数显著增高,并明显高于其他组(P<0.05)。与缺血+低氧后处理组比较,其它组TUNEL染色计数阳性细胞数都有不同程度的增高(P<0.01)。与缺血组比较,缺血+低氧后处理组海马的p-JAK2/JAK2和p-STAT3/STAT3蛋白表达水平显著升高(P<0.05)。结论低氧后处理,通过改善JAK2/STAT3通路参与,对成年大鼠短暂全脑缺血的神经有良好的保护作用,值得推广及应用。

Pretreatment of Populus tomentiglandulosa protects hippocampal CA1 pyramidal neurons from ischemia-reperfusion injury in gerbils via increasing SODs expressions and maintaining BDNF and IGF-I expressions

To examine the effects of Populus tomentiglandulosa(PT) extract on the expressions of antioxidant enzymes and neurotrophic factors in the cornu ammonis 1(CA1) region of the hippocampus at 5 min after inducing transient global cerebral ischemia(TGCI) in gerbils, TGCI was induced by occlusion of common carotid arteries for 5 min. Before ischemic surgery, 200 mg·kg–1 PT extract was orally administrated once daily for 7 d. We performed neuronal nuclear antigen immunohistochemistry and Fluoro-Jade B staining. Furthermore, we determined in situ production of superoxide anion radical, expression levels of SOD1 and SOD2 as antioxidant enzymes and brain-derived neurotrophic factor(BDNF) and insulin-like growth factor I(IGF-I) as neurotrophic factors. Pretreatment with 200 mg·kg–1 PT extract prevented neuronal death(loss). Furthermore, pretreatment with 200 mg·kg–1 PT extract significantly inhibited the production of superoxide anion radical, increased expressions of SODs and maintained expressions of BDNF and IGF-I. Such increased expressions of SODs were maintained in the neurons after IRI. In summary, pretreated PT extract can significantly increase levels of SODs and protect the neurons against TGCI, suggesting that PT can be a useful natural agent to protect against TGCI.

短暂性全面遗忘症7例临床分析

目的探讨短暂性全面性遗忘症患者的病因及临床特点。方法对7例临床诊断为短暂性全面遗忘症的患者行24 h内脑电图(EEG)、经颅多普勒超声(TCD)检查,发病1周内行头颅CT或磁共振成像(MRI)检查,5例行单光子发射计算机扫描(SPECT)检查。结果7例短暂性全面遗忘症患者中6例EEG正常,1例可见少量慢波;TCD均提示椎基底动脉供血异常;头颅CT或MRI检查,6例正常,1例腔隙性脑梗死;5例SPECT均显示不同脑区有低灌注情况。7例患者随访3～24个月,6例无复发,1例复发1次,复查SPECT左颞叶血流灌注减低。结论短暂性全面遗忘症患者均有不同程度脑缺血,提示本病可能与颞叶及海马局部缺血有关。

Blockade of HCN2 Channels Provides Neuroprotection Against Ischemic Injury via Accelerating Autophagic Degradation in Hippocampal Neurons

In the central nervous system,hyperpolarizationactivated cyclic nucleotide-gated(HCN)channels are essential to maintain normal neuronal function.Recent studies have shown that HCN channels may be involved in the pathological process of ischemic brain injury,but the mechanisms remain unclear.Autophagy is activated in cerebral ischemia,but its role in cell death/survival remains controversial.In this study,our results showed that the HCN channel blocker ZD7288 remarkably decreased the percentage of apoptotic neurons and corrected the excessive autophagy induced by oxygen-glucose deprivation followed by reperfusion(OGD/R)in hippocampal HT22 neurons.Furthermore,in the OGD/R group,p-mTOR,p-ULK1(Ser757),and p62 were significantly decreased,while p-ULK1(Ser317),atg5,and beclin1 were remarkably increased.ZD7288 did not change the expression of p-ULK1(Ser757),ULK1(Ser317),p62,Beclin1,and atg5,which are involved in regulating autophagosome formation.Besides,we found that OGD/R induced a significant increase in Cathepsin D expression,but not LAMP-1.Treatment with ZD7288 at 10μmol/L in the OGD/R group did not change the expression of cathepsin D and LAMP-1.However,chloroquine(CQ),which decreases autophagosome-lysosome fusion,eliminated the correction of excessive autophagy and neuroprotection by ZD7288.Besides,shRNA knockdown of HCN2 channels significantly reduced the accumulation of LC3-Ⅱand increased neuron survival in the OGD/R and transient global cerebral ischemia(TGCI)models,and CQ also eliminated the effects of HCN2-shRNA.Furthermore,we found that the percentage of LC3-positive puncta that co-localized with LAMP-1-positive lysosomes decreased in Con-shRNAtransfected HT22 neurons exposed to OGD/R or CQ.In HCN2-shRNA-transfected HT22 neurons,the percentage of LC3-positive puncta that co-localized with LAMP-1-positive lysosomes increased under OGD/R;however,the percentage was significantly decreased by the addition of CQ to HCN2-shRNA-transfected HT22 neurons.The present results demonstrated that blockade of HCN2 channels provides neuroprotection against OGD/R and TGCI by accelerating autophagic degradation attributable to the promotion of autophagosome and lysosome fusion.