针刺干预对脑缺血大鼠脑组织低氧诱导因子-1α蛋白和mRNA表达的影响

 目的 观察针刺干预对脑缺血大鼠脑组织缺氧诱导因子1α(hypoxia-inducible factor-1α,HIF-1α)蛋白及mRNA表达的影响,探讨针刺对缺血性脑血管疾病的防治机制。方法 建立局灶性脑缺血大鼠模型,随机分为正常组、假手术组、模型组、针刺组(各8只大鼠),应用蛋白印迹及实时荧光定量检测针刺对局灶性脑缺血大鼠脑组织HIF-1α蛋白及mRNA表达的变化。结果 正常组和假手术组大鼠比较HIF-1α蛋白及mRNA表达无明显变化,模型组大鼠HIF-1α蛋白及mRNA表达上调,差异无统计学意义;针刺组大鼠HIF-1α蛋白及mRNA表达高于模型组(0.567±0.058 vs 0.315±0.118; 1.593±0.102 vs 1.193±0.259),差异有统计学意义(P<0.05)。结论 脑缺血后大鼠脑组织HIF-1α蛋白及mRNA表达增强,针刺可以上调其表达从而发挥脑保护作用。     

运动训练对大鼠局部脑缺血再灌注后血管生成素及其受体表达的影响

目的:探讨运动训练对大鼠局部脑缺血再灌注后血管生成素及其受体表达的影响。方法:成年雄性SD大鼠42只,随机分成运动组、对照组和假手术组,每组14只。运动组和对照组采用大脑中动脉闭塞(MCAO)法造模24h后,运动组进行跑台训练,速度为12m/min,每天30min,连续2周;假手术组进行相同的造模手术,但不造成缺血。2周后采用免疫组化法观察大鼠脑缺血再灌注后Ang-1、Tie-2表达的空间分布情况,Western blot定量检测Ang-1及其受体Tie-2的表达。结果:免疫组化染色显示,Ang-1及其受体Tie-2阳性细胞主要分布在缺血侧的额顶叶皮层。Western blot结果显示,2周后,运动组Ang-1及其受体Tie-2的表达显著高于对照组(P<0.05)。结论:运动训练可上调Ang/Tie-2通路的表达,这可能是其促进脑缺血性损伤后大鼠神经功能恢复的内在原因之一。     

超顺磁性氧化铁灌注T_2WI诊断超急性脑缺血的实验研究

目的观察国产超顺磁性氧化铁（ＳＰＩＯ）灌注Ｔ２ＷＩ诊断超急性期脑缺血的可行性。方法正常大鼠５只和右侧大脑中动脉闭塞（ＭＣＡＯ）大鼠２６只,行ＳＰＩＯ灌注前后Ｔ２ＷＩ,后者在ＭＣＡＯ后４０～５０分钟行ＭＲ检查。ＭＲ检查后４只行墨汁灌注检查,６只在ＭＣＡＯ后２４小时行ＭＲ复查和病理检查。ＳＰＩＯＩ颗粒直径２０ｎｍ、ＳＰＩＯＩ颗粒直径６～９ｎｍ,剂量为０６ｍｍｏｌ／ｋｇ。采用ＳＰＩＯＩ做了６只、ＳＰＩＯＩ做了２０只灌注检查。结果在ＭＣＡＯ后５０分钟,平扫Ｔ２ＷＩ仅３７％表现右侧大脑中动脉（ＭＣＡ）供血区信号稍高;两种型号的ＳＰＩＯ灌注后１００％或８０％的右侧ＭＣＡ供血区呈相对高信号,与墨汁灌注检查的灌注缺损区及ＭＣＡＯ后２４小时复查Ｔ２ＷＩ的高信号范围一致。病理检查证实右侧ＭＣＡ供血区的缺血、梗死。在剂量相同情况下,ＳＰＩＯＩ灌注Ｔ２ＷＩ显示缺血区与非缺血区的对比度明显高于ＳＰＩＯＩ。结论ＳＰＩＯ相当于一种阴性造影剂,国产ＳＰＩＯ“灌注”常规Ｔ２ＷＩ可以诊断血管闭塞５０分钟的急性脑缺血,ＳＰＩＯＩ灌注的诊断效果优于ＳＰＩＯＩ。     

WIN 55,22-2对大鼠局灶性脑缺血再灌注损伤的保护作用

目的:探讨大麻素(CB)受体激动剂WIN55,212-2对大鼠局灶性脑缺血的保护作用。方法:采用大鼠大脑中动脉栓塞(MCAO)致局灶性脑缺血模型。将50只雄性SD大鼠随机分为5组:对照组(Con组)于MCAO前30 min腹腔注射生理盐水0.3 ml;WIN55,212-2组(WIN1~3组)于MCAO前30 min腹腔注射WIN55,212-2 0.3,1和3 mg/kg;DMSO组于MCAO前30 min腹腔注射二甲基亚砜(DMSO)0.3 ml。观察MCAO120 min再灌注24 h后神经功能评分(NFS)和脑梗死容积百分比。结果:与DMSO组和Con组比较,WIN55,212-2组大鼠NFS明显升高(P<0.05),脑梗死容积百分比明显减小(P<0.05)。结论:CB受体激动剂WIN55,212-2对大鼠局灶性脑缺血再灌注损伤具有保护作用,并具有一定的剂量相关性。     

缺血后处理对局灶性脑缺血再灌注大鼠SOD、MDA的影响

目的：观察缺血后处理对局灶性脑缺血再灌注大鼠SOD、MDA的影响。方法：线栓法建立大鼠大脑中动脉缺血再灌注模型,将成年雄性Wistar大鼠144只,随机分成三组：假手术组、对照组（脑缺血再灌注组）、缺血后处理组？假手术组只进行假手术;对照组（脑缺血再灌注组）给予90min大脑中动脉缺血（MCAO）;缺血后处理组在大脑中动脉缺血90rain后,给予灌注30s缺血30s,反复3次。各组分别再灌注1211、24h、48h、72h后测定脑组织超氧化物歧化酶（SOD）、丙二醛（MDA）水平的改变：结果：局灶性脑缺血后再灌注前给予后处理,缺血后处理组与缺血再灌注组相比,SOD的表达明显增加,而MDA的表达明显减少。结论：脑缺血后处理增加脑缺血再灌注后SOD的表达、减少MDA的表达,进而提高脑组织的抗氧化能力。     

金丝桃苷对大鼠脑缺血再灌注氧化应激损伤的影响

目的 探讨金丝桃苷（Hyperin,Hyp）对大鼠局灶性脑缺血再灌注氧化应激损伤的影响。方法 （1）模型制备：采用线栓法制备大鼠大脑中动脉缺血模型,缺血2h再灌注。（2）抗氧化实验：40只大鼠随机分成假手术组、模型组、Hyp低剂量组和高剂量组,每组10只。给药组术前连续ig5d,于末次给药30min后行手术。造模24h后检测大鼠脑组织的超氧化物岐化酶（SOD）活性和丙二醛（MDA）含量。（3）病理组织学实验：另取40只大鼠分组和治疗同上,造模24h后,进行神经行为学评分,光镜下观察脑梗死部位病理学改变。结果与模型组比较,神经行为学评分明显降低（P〈0．01）;Hyp—L、Hyp—S剂量组SOD活性均明显提高（P〈0．01）,且两组的MDA含量也显著降低（P〈0．05）;镜下观察给药组多数神经元结构较完整,形态相对正常,细胞及间质水肿减轻。结论 Hyp对大鼠局灶性脑缺血再灌注氧化应激损伤有明显保护作用。     

甾体皂苷化合物对局灶性脑缺血大鼠的保护作用

目的：研究甾体皂苷化合物(化合物9714)对局灶性脑缺血大鼠的影响。方法：采用FeCl3局部损伤血管，诱发血栓形成，造成局灶性脑缺血模型，观察化合物9714对模型大鼠神经症状、脑梗塞范围、脑水肿以及皮质血管脑血流量的影响。结果：化合物9714 20，40mg／kg组能明显减轻模型大鼠的神经症状及脑梗塞范围，增加模型大鼠的脑血流量；化合物9714 40mg／kg组能明显改善模型大鼠的患侧脑水肿程度，延长脑血流量下降50％所需时间。结论：化合物9714对血栓所致局灶性脑缺血性损伤具有明显的修复作用。     

Neuroprotective effects of an immunosuppressant agent on diffusion/perfusion mismatch in transient focal ischemia.

The immunosuppressant FK506 (tacrolimus) exerts potent neuroprotection following focal ischemia in animals; however, the separate effects of FK506 on the ischemic core and penumbra have not been reported. The ischemic penumbra is clinically defined as the difference between a large abnormal area on perfusion-weighted imaging (PWI) and a smaller lesion on diffusion-weighted imaging (DWI). The goal of this study was to determine the effect of FK506 on DWI/PWI match and mismatch areas in transient focal ischemia in rats. Twelve rats were subjected to 1 hr of transient middle cerebral artery (MCA) occlusion, and given an intravenous injection of a placebo (N = 6) or 1 mg/kg FK506 (N = 6) immediately before reperfusion. Magnetic resonance imaging (MRI) was performed during MCA occlusion, and 0.5, 1, and 24 hr after reperfusion. FK506 significantly protected the ischemic brain only in the mismatch cortex where the initial apparent diffusion coefficient (ADC) was normal and there was a mild reduction of cerebral blood flow (CBF). This is the first report to describe the protective effects of FK506 on ischemic penumbra, as measured by DWI/PWI mismatch. The findings provide direct evidence for the utility of DWI/PWI mismatch as a guideline for therapeutic intervention with FK506.     

丁苯酞对缺血脑组织RGMa表达及轴索损伤的影响

目的:探讨丁苯酞对缺血性脑损伤后缺血脑组织排斥导向分子(RGMa)表达的影响.方法:120只成年雄性SD大鼠,随机分为假手术组,大脑中动脉闭塞(MCAO)模型组,生理盐水组,丁苯酞干预组.选取缺血后1h、3h、6h、12h、24h,进行神经功能评分,免疫组织化学观察RGMa的表达情况.结果:MCAO模型组、生理盐水组、丁苯酞组的改良的神经功能评分(mNSS)均高于假手术组,且随着时间的延长,mNSS评分越高;在缺血后3h、6h、12h、24h时,丁苯酞组的mNSS评分较MCAO模型组降低,差异具有统计学意义(P＜0.05).MCAO模型组、生理盐水组大鼠缺血后,不同时间点缺血区的RGMa蛋白阳性表达均有所增加,呈棕黄色染色.局灶性脑缺血后RGMa蛋白表达逐渐增多,在12h表达量最多;丁苯酞组在相应时间点的RGMa蛋白的表达较MCAO模型组有所降低,在6h、12h、24h时间点差异具有统计学意义.结论:丁苯酞可减少缺血性脑损伤大鼠的缺血脑组织的RGMa的表达,从而发挥神经功能保护作用.     

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 fluorescence.

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.     

局灶性脑缺血后脑血流变化及血流储备能力的CT评价

目的:应用动态增强CT灌注成像评价局灶性脑缺血后脑血流储备能力的变化。方法:将15只大鼠随机分为脑缺血0.5、1、3和6h组和假手术对照组,进行脑缺血静息态CT灌注测试。9只动物随机分为脑缺血0.5、1h组和假手术盐水组,进行脑缺血负荷CT灌注测试;脑缺血组动物CT扫描前给予乙酰唑胺静脉制剂Diamox,假手术盐水组CT扫描前给予相当量的生理盐水。所有动物24h行MRI和MRA扫描。结果:静息状态脑缺血后30min及以后各时间点CBF、CBV、MTT图及原始图像上均可见大脑中动脉供血区脑组织低灌注改变,0.5~1h低灌注范围逐渐扩大,程度加重,其后低灌注范围和程度变化不大。早期纹状体CBF和CBV降低,MTT延长,但皮质CBF轻度下降,CBV维持正常或略偏高水平,MTT延长,1h后CBF、CBV明显下降。负荷状态脑缺血30minCBF异常范围较静息时增大,纹状体和皮质CBF均已明显下降;脑缺血1h低灌注范围与静息状态相差无几但低灌注程度加重;提示以上两个时间点缺血区血流储备能力下降。假手术动物脑CT灌注图像上脑组织未出现灌注异常。结论:Diamox负荷前后脑灌注CT测定能够用于脑血流储备能力的评价。局灶性脑缺血后脑血流存在时间和空间上的变化规律,CBV是反映组织血流调节能力的一个指标,局灶性脑缺血后血流储备能力降低。     

急性大脑中动脉阻塞模型的磁共振弥散成像及相关病理基础研究

目的观察兔大脑中动脉阻塞后常规MRI及DWI表现,阐明活体脑缺血后DWI的演变规律及其病理生理机制方法40只成年新西兰大白兔随机分成2组,对照组4只,实验组36只实验组采用Yamamoto法制作急性大脑中动脉阻塞(MCAO)模型,对照组仅曝露大脑中动脉,而不结扎观察MCAO后缺血区在各时段ADC值的变化规律,并进行病理学检查结果对照组:T2WI及DWI均无高信号出现,光镜检查均无异常改变实验组:DWI上,MCAO后0.5h基底节区出现高信号;T2WI最早于2h出现高信号,早期ADC值快速下降的病理基础是缺血后细胞内的水含量的增加;ADC值下降减慢及相对平台期的病理基础是血脑屏障破坏的逐渐加重及血管源性水肿的出现;而ADC值的上升的病理基础是细胞的死亡、溶解,血脑屏障的破坏结论早期的扩散异常区域并不意味着病灶已发生梗死,当持续缺血达6h以上,脑组织将产生不可逆的损伤     

Interleukin-1 exacerbates focal cerebral ischemia and reduces ischemic brain temperature in the rat.

The proinflammatory cytokine interleukin-1 (IL-1) is a key mediator of inflammation in cerebral ischemia, but its precise mechanisms of action remain elusive. Temperature is critical to outcome in brain injury and given the importance of IL-1 in pyrogenesis this has clear mechanistic implications. IL-1 exacerbates ischemia independently of core (rectal) temperature. However, it is temperature in the ischemic brain that influences outcome and rectal temperature is likely to be a poor surrogate marker. This study tested the hypothesis that IL-1 exacerbates cerebral ischemia by increasing ischemic brain temperature. Wistar rats undergoing transient middle cerebral artery occlusion received either 4 microg/kg IL-1 (n=9) or vehicle (n=10) intraperitoneally. NMR-generated maps of brain temperature, tissue perfusion, and the trace of the diffusion tensor were collected during occlusion, early reperfusion, and at 24 hr. IL-1 significantly increased ischemic damage at 24 hr by 35% but rectal temperature did not vary significantly between groups. However, ischemic brain was 1.7 degrees C cooler on reperfusion in IL-1-treated animals (vs. vehicle) and a corresponding reduction in cerebral blood flow was identified in the ischemic striatum. Contrary to the stated hypothesis, IL-1 reduced ischemic brain temperature during reperfusion and this may be due to a reduction in tissue perfusion.     

纳络酮对脑梗死大鼠脑损伤的保护作用及对能量代谢的影响

 目的 观察纳络酮对脑缺血再灌注大鼠脑损伤的保护作用及对能量代谢的影响.方法 采用线栓法建立大鼠局灶性脑缺血-再灌注模型,给予纳络酮后测定大鼠脑梗死面积、神经行为评分、脑含水量;制作脑组织匀浆测定脑组织中丙二醛(MDA)含量、超氧化物岐化酶(SOD)活性,并用HPLC测定脑组织ATP含量和能量负荷值.结果 给予纳络酮后大鼠脑梗死面积显著缩小,神经行为障碍显著改善,脑组织水肿得到延缓,丙二醛(MDA)含量显著降低,且脑组织中ATP含量和能荷值显著升高.结论 纳络酮对大鼠局灶性脑缺血再灌注损伤有保护作用,其可能机制在于改善了脑组织的能量代谢.＃     

积雪草酸对大鼠局灶性脑缺血再灌注损伤的保护作用研究

目的研究积雪草酸对大鼠局灶性脑缺血再灌注损伤的保护作用及其可能机制。方法Wistar♂大鼠随机分为6组：积雪草酸低、中、高剂量组（50、100、200mg·kg^-1·d^-1）,阳性对照杏灵颗粒组（300mg·kg^-1·d^-1）,模型组和假手术组;大鼠灌胃给药,1次/d,连续7d,末次给药60min后采用线栓法制作大鼠局灶性脑缺血再灌注模型,缺血2h再灌注24h后对大鼠神经功能进行评分,并测定脑梗死体积、脑含水量、脑组织中白细胞介素-β（IL-β）和肿瘤坏死因子-α（TNF-α）的含量。结果与模型组相比,积雪草酸能够显著降低脑梗死体积和脑含水量,减少脑组织中的IL-1β和TNF-α含量（P〈0.01,P〈0.05）。结论积雪草酸对大鼠局灶性脑缺血再灌注损伤具有显著的保护作用,其机制可能与降低脑组织中的IL-1β和TNF-α含量有关。     

DWI及PWI对川芎嗪治疗急性脑缺血疗效监测的实验研究

目的利用DW I及PW I动态观察缺血前预注川芎嗪(TMP)对大鼠缺血后脑实质的系列变化,探讨功能磁共振成像在脑缺血神经保护药物的作用机理、疗效监测方面的应用价值。方法建立大鼠急性脑缺血再灌注模型,30只雄性SD大鼠(280~320 g),随机分成2组(每组,n=15):实验组(A组)和对照组(B组),分别于缺血前30 m in腹腔注射TMP 100 mg/kg和生理盐水1 m l。A组、B组分别于阻闭2 h后抽出尼龙线,恢复再灌注。于再通前,再通后1、2、3、6、12 h及24 h行功能及常规磁共振扫描。对2组结果进行比较分析。结果(1)DW I显示在缺血前腹腔注射TMP 100 mg/kg可明显缩小缺血后各时间点脑缺血面积,与对照组相比,差异有统计学意义(Ρ<0.05)。(2)急性期病灶中心血流灌注减少程度2组间差异无统计学意义(P>0.05)。结论DW I及PW I可以很好地观察TMP对大鼠缺血后脑实质保护作用的动态变化,显示功能磁共振在脑缺血神经保护药物的作用机理、疗效监测等方面具有极大的应用潜力。     

人参皂甙Rg1对大鼠局灶性脑缺血脑组织神经干细胞增殖的影响

目的 观察人参皂甙Rg1对大鼠局灶性脑缺血脑组织神经干细胞增殖的影响,探讨其在脑保护及抗衰老作用中的可能机制.方法 取成年雄性Wistar大鼠,用线栓法制作大鼠大脑中动脉闭塞(MCAO)模型,采用脉冲标记法,经腹腔注射5′-溴脱氧尿苷(BrdU)标记处于增殖状态的神经干细胞,用免疫组织化学单标及双标免疫荧光技术观察人参皂甙Rg1对局灶性脑缺血后BrdU和巢蛋白(nestin)的免疫活性及nestin/BrdU双标阳性细胞的影响,镜下观察脑内神经干细胞的分布,并计数行定量分析.结果 局灶性脑缺血后大鼠室管膜下区及海马齿状回有nestin、BrdU及nestin/BrdU双标免疫阳性细胞分布.应用人参皂甙Rg1后,上述各部位阳性细胞数明显增多,与缺血组之间有显著性差异(P＜0.01).结论 人参皂甙Rg1具有促使神经干细胞增殖的能力,这可能是其神经保护及抗衰老作用的机制之一.     

Real-time observation of transient focal ischemia and hyperemia in cat brain.

Gradient-recalled echo-planar (T2*-weighted) imaging was used to noninvasively monitor regional blood oxygenation state changes in real time during transient episodes of focal ischemia in cat brain. Varying ischemic intervals (12 s to 30 min) were caused by middle cerebral artery occlusion. A rapid signal drop was noted upon occlusion, due to deoxygenation of static blood in the ischemic tissues. Upon successful reperfusion, the signal intensity recovered immediately and increased above (overshot) the baseline level before slowly returning to normal. The "overshoot" response was strongly dependent on the duration of the ischemic interval and is thought to reflect reactive hyperemia.     

Does a relative perfusion measure predict cerebral infarct size?

BACKGROUND AND PURPOSE: MR perfusion-weighted imaging (PWI) has been extensively used to quantify cerebral perfusion deficits after the onset of focal ischemia. The present study tested whether a relative measure of cerebral blood flow such as is obtained with PWI is sufficient to predict irreversible tissue damage following focal cerebral ischemia and reperfusion in the rat suture model. METHODS: In rats, the middle cerebral artery was occluded (MCAO) for 1 hour followed by 1-hour reperfusion. Microspheres labeled with different tracers were injected into the left ventricle to permit measurement of blood flow at different time points: before MCAO, 30 minutes post-MCAO and 30 minutes postreperfusion. Absolute cerebral blood flow (CBF) was determined and relative CBF was calculated by comparing absolute CBF at each time point to baseline values before MCAO (relative CBF(B)) or to corresponding contralateral areas in the noninfarcted hemisphere (relative CBF(C)). Infarct size was assessed by 2,3,5-triphenyltetrazolium chloride staining. RESULTS: Absolute CBF in vital tissue was 0.69 +/- 0.07 mL/g/min. In partially and completely necrotic tissue, absolute CBF was 0.39 +/- 0.05 mL/g/min and 0.30 +/- 0.09 mL/g/min, respectively. Although there was a close inverse correlation between infarct volume and absolute CBF (r = 0.79), the correlations between infarct volume and relative CBF(C) were poor (r = 0.21). CONCLUSION: The present study revealed that absolute CBF is superior to relative CBF in predicting irreversible tissue damage following ischemia and reperfusion.     

促红细胞生成素对大鼠脑缺血再灌注后STAT1和STAT3表达的影响及MRI表现

目的探讨促红细胞生成素(EPO)对大鼠局灶性脑缺血再灌注后脑梗死面积变化及信号转导与转录激活子-1(STAT1)、磷酸化STAT1(P-STAT1)、信号转导与转录激活子-3(STAT3)、磷酸化STAT3(P-STAT3)蛋白表达的影响。方法雄性健康SD大鼠40只,随机分为假手术组(A)、脑缺血再灌注组(B)、生理盐水治疗组(C)、EPO治疗组(D),采用线栓法阻断大鼠一侧大脑中动脉血流2 h,再灌注24 h,建成局灶性脑缺血再灌注损伤模型。治疗组于脑缺血刚开始时腹腔注射EPO或等量生理盐水,于24 h时行MRI检查观察脑梗死面积,采用Western blotting检测STAT1、P-STAT1、STAT3、P-STAT3蛋白表达水平的变化。结果与B、C组相比,D组脑梗死面积减小(P<0.05),STAT3磷酸化水平增加(P<0.05),STAT1磷酸化水平有所减少。结论 EPO可能通过影响JAK/STAT信号转导通路减小脑梗死面积。