大鼠脑缺血再灌注损伤后脑组织STAT3变化的免疫组织化学研究

目的 探讨信号转导和转录激活子（ＳＴＡＴ）３在大鼠局灶性脑缺血再灌注损伤中的表达及其与缺血性神经细胞损伤的关系方法 用ＡＢＣ免疫组化方法观察大鼠局灶性脑缺血再灌注损伤后脑组织中的ＳＴＡＴ３蛋白免疫反应阳性细胞分布。结果 正常和假手术大鼠脑内以及脑缺血后的非缺血半球脑组织中未发现有ＳＴＡＴ３免疫反应阳性细胞,脑缺血再灌注损伤后１２小时在栓塞侧梗死区可见少量ＳＴＡＴ３免疫阳性细胞,２４小时后阳性细胞显著增多达高峰,在缺血侧纹状体和缺血皮质周边区表达最明显,１周后梗死周边区少数神经细胞仍有阳性表达。差异有显著意义（Ｐ〈０．０１）。结论 ＳＴＡＴ３活化及超量表达可能介导了缺血神经细胞信号转导过程,并参与了脑缺血神经细胞损伤与修复的病理生理过程。     

酪氨酸激酶A和酪氨酸激酶B与 脑缺血缺氧性损伤

酪氨酸激酶A（TrkA）和酪氨酸激酶B（TrkB）是神经营养因子的高亲和力受体，通过与其 特异性配体（神经生长因子和脑源性神经营养因子）结合，发挥对脑缺血缺氧性损伤的保护作用。 它们与脑缺血缺氧的关系已成为近年来一个研究热点。本文从TrkA和TrkB在脑缺血缺氧性损伤后的 表达、作用及其保护机制方面进行综述。     

红景天保护缺血再灌注损伤鼠脑细胞的作用及机理研究

目的研究红景天对大鼠脑缺血再灌注损伤的作用。方法４ＶＯ法复制缺血再灌注动物模型;放免法及化学发光法测定乙酰胆碱（Ａｃｈ）、一氧化氮（ＮＯ）及内皮素（ＥＴ）含量;细胞培养观察红景天对神经细胞的作用。结果（１）缺血再灌注组（ＩＲ）Ａｃｈ含量显著低于假手术组（ＳＡＭ）,药物预防后缺血再灌注组（Ｒ＋ＩＲ）及缺血再灌注后药物治疗组（ＩＲ＋Ｒ）较ＩＲ组显著升高。（２）ＩＲ组ＮＯ含量显著高于ＳＡＭ组,Ｒ＋ＩＲ组及ＩＲ＋Ｒ组ＮＯ含量显著降低。（３）ＩＲ组ＥＴ含量显著高于ＳＡＭ组而Ｒ＋ＩＲ组显著降低。（４）红景天甙培养组细胞存活率及ＬＤＨ含量明显高于对照组,ＮＭＤＡ损伤＋红景天甙组细胞存活率明显高于ＮＭＤＡ损伤组,ＬＤＨ含量却明显降低。结论红景天对大鼠脑缺血再灌注损伤时脑神经细胞具有保护作用。     

脑缺血再灌注时红细胞免疫功能变化及中性粘多糖对其的影响

本文采用脑缺血再灌注模型，观察沙土鼠红细胞免疫粘附（ＲＣＩＡ）功能变化，红细胞Ｃ３ｂ受体花环率（ＲＢＣ－Ｃ３ｂＲＲ）、红细胞免疫复合物花环率（ＲＢＣ－ＩＣＲ），和中性粘多糖（ＮＭ）对沙土鼠红细胞免疫功能的影响。结果表明：（１）缺血时ＲＢＣ－Ｃ３ｂＲＲ下降不明显（Ｐ〉０．０５），再灌注时明显下降（Ｐ〈０．００１）；（２）缺血和再灌注时ＲＢＣ－ＩＣＲ均升高（Ｐ〈０．００１）；３．提前用ＮＭ可提高再灌注     

SOD对脑缺血—再灌注损伤大鼠纹状体谷氨酸转运体功能的影响

目的 探讨超氧化物歧化酶（ＳＯＤ）对缺血－再灌注损伤（Ｉ－Ｒ）大鼠纹状体谷氨酸转运体功能（ＧＴＦ）的影响。方法 采用大鼠三血管夹闭、松夹制作脑Ｉ－Ｒ损伤模型。利用脑组织突触膜颗粒对＾３Ｈ－Ｌ－谷氨酸摄入量的测定及分光光度法观察ＧＴＦ的改变,同时测定组织丙二醛（ＭＤＡ）的含量及ＳＯＤ活性的变化。     

MCAO后鼠脑Glu.GluR变化规律及意义

为探索谷氨酸受体（GluR）在介导谷氨酸（Glu）对缺血神经元损伤的作用机制，本实验建立大鼠大脑中动脉阻塞（MCAO）局部脑缺血实验模型，应用受体的放射配基结合分析（RBA）等技术动．态监测了缺血及再灌流期缺血灶、海马和下丘脑Glu、GluR含量及其亲和力的变化。结果发现：缺血30min，各脑区Glu含量达高峰，再灌流6h，Glu含量回降至基线水平，再灌流48h后，Glu含量再次中等程度升高，并持续至再灌流72h。GluR和KD值与Glu含量密切相关。结果提示，缺血再灌流早期，GluR在高浓度Glu的作用下发生同种特异性反向调节，GluR亲和力为增敏反应；再灌流中晚期，GluR的变化属于同种特异性正向调节，而GluR亲和力测为减敏反应。     

小檗碱对大鼠脑缺血后MCP-1表达的影响

目的探讨小檗碱处理对大鼠脑缺血后单核细胞趋化蛋白-1（MCP-1）表达的影响及小檗碱对脑缺血的神经保护作用。方法建立大鼠短暂性全脑缺血模型，采用尼氏体亚甲蓝染色观察脑缺血后大鼠脑海马CA1区神经元存活情况；采用免疫荧光染色方法检测脑缺血后大鼠缺血脑组织中MCP-1的表达情况。结果（1）与假手术组比较，脑缺血组大鼠脑海马CA1区神经元明显缺失，而小檗碱处理组大鼠脑海马CA1区神经元存活数明显多于缺血对照组；（2）与假手术组比较，脑缺血组大鼠脑缺血区MCP-1表达显著增多，而小檗碱处理显著降低了大鼠脑缺血区MCP-1的阳性表达。结论脑缺血引起MCP-1表达上调，提示MCP-1可能参与脑缺血损伤。小檗碱可抑制缺血脑组织MCP-1的表达，推测其可能经此途径减轻脑缺血的炎症反应而发挥一定的神经保护作用。     

肾血管性高血压鼠及局部脑缺血后下丘脑和血浆中内皮素,降钙素基因…

实验测定了肾血管性高血压大鼠（ＲＨＲ）不同鼠龄下丘脑和血浆ＥＴ，ＣＧＲＰ水平以及局部脑缺血后不同时期的变化，结果发现：３，７月龄ＲＨＲ其下丘脑和血浆中的ＥＴ水平明显高于对照鼠，局部脑缺血组１天，ＲＨＲ和对照鼠的下丘脑及血浆中ＥＴ，ＣＧＲＰ水平均比缺血前增高，缺血７天时，对照鼠ＥＴ，ＣＧＲＰ均恢复至缺血前水平，而在ＲＨＲ，下丘脑和血浆ＥＴ仍高于缺血前水平，提示，高水平的ＥＴ可能参与ＲＨＲ高血压的形成     

氟美松对成年大鼠持续性局灶脑缺血后细胞凋亡和Fas基因表达的作用

目的 研究氟美松对成年人局灶性脑缺血后细胞凋亡及相关Ｆａｓ基因表达的作用。方法 健康雄性ＳＤ大鼠随机分成１４组（每组５只）。１～７组为对照组，８～１４组为实验组。用右侧近端大脑中动脉电凝术建立大鼠持续性局灶性脑缺血模型。缺血后１ｈ，实验组动物尾静脉射氟美松（５ｍｇ／ｋｇ），对照组注射生理盐水。分别在缺血后３、６、１２、２４、４８、７２和１２０ｈ取材，用原位末端标记（ＴＵＮＥＬ法）、原位ＲＴ－ＰＣＲ法分别检测缺血后细胞凋亡和Ｆａｓ ｍＲＮＡ表达并进行了半定量分析。结果 氟美松可导致缺血后细胞凋亡提前发生，促进大鼠局灶性脑缺血后Ｆａｓ ｍＲＮＡ的表达，使其表达开始时间提前、表达持续时间延长、表达细胞增多及表达信号增强。结论 氟美松可促缺血后细胞凋亡相关基因Ｆａｓ ｍＲＮＡ的表达，可能是其加重成年大鼠缺血性脑损伤尤其     

肾血管性高血压鼠及局部脑缺血后下丘脑和血浆中内皮素、降钙素基因相关肽水平的变化

实验测定了肾血管性高血压大鼠（ＲＨＲ）不同鼠龄下丘脑和血浆ＥＴ、ＣＧＲＰ水平以及局部脑缺血后不同时期的变化。结果发现，３，７月龄ＲＨＲ其下丘脑和血浆中的ＥＴ水平明显高于对照鼠。局部脑缺血组１天，ＲＨＲ和对照鼠的下丘脑及血浆中ＥＴ、ＣＧＲＰ水平均比缺血前增高，缺血７天时，对照鼠ＥＴ、ＣＧＲＰ均恢复至缺血前水平，而在ＲＨＲ，下丘脑和血浆ＥＴ仍高于缺血前水平，提示：高水平的ＥＴ可能参与了ＲＨＲ高血压的形成和发展，而局部脑缺血后，ＥＴ大量持续释放，可能是导致高血压性脑梗塞患者恢复慢，疗效差的原因之一。     

Magnetic resonance imaging of experimental cerebral ischemia: correlations between NMR parameters and water content

Recent studies on proton NMR imaging revealed its remarkable sensitivity for detecting cerebral ischemia. Since proton NMR reflects the distribution and state of water in the brain, an NMR imager becomes a sensitive in vivo detector of brain edema developing soon after the energy state is compromized by ischemia. To further clarify the usefulness of NMR imaging to characterize the ischemia-induced changes, correlations between T1 and T2 relaxation times and water content of the normal and ischemic rat and gerbil brain were studied by means of both spectroscopic and in vivo imaging methods. In the spectroscopic experiment on excised rat brain (cortex, white matter, hippocampus and thalamus for normal and ischemia-laden brain), T1 and T2 relaxation times and water content were determined. The ischemic insult was induced for 60 min by the method of Pulsinelli followed by 60 min of reperfusion. All of the T1, T2 and water content significantly increased in the ischemic tissue. Gray-white difference was evident in T1 and T1 was linearly correlated with the water content of the tissue. T2 was by far prolonged in the ischemic tissue compared with the increase in the water content, showing greater sensitivity of T2 for detection of ischemia. In the imaging experiment, coronal NMR imaging at 0.5 tesla was performed employing proton density-weighted saturation recovery (TR = 1.6 s, TE = 14 ms), T1-weighted inversion recovery (TR = 1.6 s, TI = 300 ms, TE = 14 ms) and T2-weighted spin echo (TR = 1.6 s, TE = 106 ms) pulse sequences.(ABSTRACT TRUNCATED AT 250 WORDS)     

氯沙坦对局部脑缺血大鼠脑血管紧张素Ⅱ 1型受体mRNA表达的影响

目的研究大鼠局部脑缺血后血管紧张素Ⅱ(AngⅡ)1型受体mRNA(AT1RmRNA)基因的表达及氯沙坦对其影响。方法将36只SD雄性大鼠按时间段随机分为2组(每组各18只),每组再随机分为假手术组、缺血组和氯沙坦用药组3个亚组(每组各6只)。采用尼龙线栓塞大鼠大脑中动脉而造成局部脑缺血模型,应用RTPCR方法检测脑组织缺血24、48h后缺血侧及非缺血侧大脑皮层AT1RmRNA的表达水平。结果脑缺血24h各组缺血侧及非缺血侧大脑皮层AT1RmRNA表达水平无差异(p>0.05);脑缺血48h后与假手术组比较,缺血组缺血侧及非缺血侧大脑皮层AT1RmRNA表达水平升高(P均<0.05);而与缺血组比较,氯沙坦用药组缺血侧及非缺血侧大脑皮层AT1RmRNA表达水平降低(P均<0.05),但仍高于假手术组(P均<0.05)。结论氯沙坦能降低局部脑缺血后AT1RmRNA表达水平,AT1R在局部脑缺血中起着重要的作用,它可能成为缺血性脑卒中的一个治疗靶点。     

脑缺血时大鼠大脑皮层乙酰胆碱含量变化的动态观察

本实验采用双侧颈总动脉夹闭（ＣＣＡＯ）和大脑中动脉闭塞（ＭＣＡＯ）两种脑缺血动物模型，分别用乙酰胆碱（ＡＣｈ）生物测定法检测皮层ＡＣｈ含量，ＡＣｈ离子选择性微电极（ＡＣｈ－ＩＳＭｓ）检测皮层ＡＣｈ释放量，乙酰胆碱酯酶（ＡＣｈＥ）生化测定法检测皮层ＡＣｈＥ活性，观察脑缺血时皮层ＡＣｈ含量的动态查化。结果发现：脑缺血可诱发皮层ＡＣｈ活度急剧上升，示ＡＣｈ突然大量释放，在ＣＣＡＯ组于缺血１０ｍｉｎ达到高峰（净增１．４４４ｍｍｏｌ／Ｌ），而ＭＣＡＯ组于缺血２ｍｉｎ即达高峰（净增１．５５３ｍｍｏｌ／Ｌ），随着缺血延长，二者均逐渐下降，于缺血３０ｍｉｎ时，虽较峰值要低，但明显高于缺血前水平，此时，ＡＣｈＥ活性巳明显低于缺血前，ＡＣｈ含量在ＣＣＡＯ组下降０．２５６μｇ／ｇ（Ｐ＞０．０５），在ＭＣＡＯ组则显著下降１．０１４μｇ／ｇ（Ｐ＜０．０１）。结果提示：皮层ＡＣｈ含量变化对缺血是敏感的；脑缺血时ＡＣｈ含量下降、释放增加、降解减弱，推测ＡＣｈ可能在缺血性脑损伤中起重要作用。     

尼莫地平对局灶性脑缺血鼠脑血影蛋白的影响

目的 观察大脑中动脉（MCA）缺血后血影蛋白的动态变化,寻找反映脑缺血程度的形态学依据。并评价尼莫地平的脑保护作用。方法 制作大鼠MCA局灶性脑缺血模型。免疫组化法检测血影蛋白含量。缺血后10min,30min,3h,6h和48h观察血影蛋白动态变化。结果 缺血后10min缺血区域血影蛋白表达降低。24h达高峰,尼莫地平可减少缺血区神经元血影蛋白的降解,具有脑保护作用。结论 检测血影蛋白可反映神经元缺血损伤后的早期形态学改变,钙离子拮抗剂一尼莫地平有重要的脑保护作用。     

Induction of NADPH-diaphorase activity in the hippocampus in a rat model of cerebral ischemia and ischemic tolerance

Preconditioning of the brain with sublethal ischemia induces tolerance to subsequent lethal periods of ischemia (ischemic tolerance). In this study, we used NADPH-diaphorase histochemistry to investigate the postischemic changes of nitric oxide synthase (NOS) in the hippocampus in a rat model of cerebral ischemia and ischemic tolerance. Forebrain ischemia was induced by 4-vessel occlusion for 3 min as an ischemic preconditioning. Three days after the preconditioning or sham operation, second ischemia was induced for 6 min. A transient increase in NADPH-diaphorase activity, beginning after 2 h and maximal after 1 day, was observed in CA1 pyramidal neurons of rats subjected to 3 min of preconditioning ischemia as well as 6 min of subsequent ischemia both with and without preconditioning. In addition, expression of NADPH-diaphorase activity was seen in reactive glial cells in the damaged CA1 region of animals subjected to 6 min of ischemia without preconditioning. Thus, direct involvement of increased NADPH-diaphorase activity in ischemic tolerance was not suggested because the increased NADPH-diaphorase activity preceded the induction of ischemic tolerance which takes place 1–7 days after preconditioning. However, the present findings suggest that the induction of neuronal NADPH-diaphorase activity occurs in response to cerebral ischemia.     

神经节苷脂对大鼠脑缺血再灌注损伤的脑保护作用

目的探讨神经节苷脂对大鼠脑缺血再灌注损伤的脑保护作用。方法采用线栓法制作缺血再灌注大鼠模型,分别用神经节苷脂(治疗组)和生理盐水(对照组)腹腔注射。观察两组大鼠缺血90min、缺血90min再灌注24h的脑梗死面积、神经功能缺损程度、细胞凋亡数、细胞凋亡率。结果治疗组大鼠于相同时间点脑梗死面积较对照组明显减小,仅表现轻度的神经功能缺损,且神经细胞的凋亡数较对照组显著减少(均P<0.01)。结论神经节苷脂能明显减小大鼠实验性脑缺血的脑梗死面积,减轻脑缺血再灌注后神经功能缺损程度,显著减轻缺血区神经元损害,具有显著的脑保护作用。     

脑缺血再灌流［~3H］—三磷酸肌醇放射活性及突触体游离Ca~（2＋）的变化

本文研究了大鼠脑缺血再灌流时［３Ｈ］—三磷酸肌醇（［３Ｈ］－ＩＰ３）放射活性及突触体游离Ｃａ２＋（［Ｃａ２＋］ｉ）的变化，并用苯甲基磺酰氟化物（ＰＭＳＦ）治疗，观察其对［３Ｈ］－ＩＰ３放射活性及突触体［Ｃａ２＋］ｉ的影响。结果：脑缺血１ｍｉｎ［３Ｈ］－ＩＰ３放射活性非常显著地增高。缺血２０ｍｉｎ、缺血２０ｍｉｎ再灌流１ｈ、６ｈ、２ｄ［３Ｈ］－ＩＰ３放射活性非常显著地降低。缺血２０ｍｉｎ突触体［Ｃａ２＋］ｉ非常显著地增高，至再灌流６ｈ达到最高水平。应用ＰＭＳＦ治疗能显著地抑制突触体［Ｃａ２＋］ｉ的升高。     

缺血脑组织内皮素含量变化的实验研究

为探讨内皮素含量变化是否为缺血神经元损伤的危险因素及Ca~(2+)拮抗剂氟桂嗪对脑缺血的保护作用,采用放射免疫分析法,我们测定兔大脑中动脉阻断48小时后缺血区脑组织内皮素含量变化及氟桂嗪对其变化的影响。结果显示,缺血48小时后梗塞区脑组织内皮素含量明显升高(P<0.01),为对照组的10倍,而氟桂嗪能明显降低缺血区脑组织水、内皮素含量(P<0.05)。上述结果提示:缺血脑组织内皮素含量升高是导致缺血神经元损伤的重要因素,氟桂嗪对脑缺血有保护作用。     

Effect of the reperfusion after cerebral ischemia in neonatal rats using MRI monitoring

Cerebral hypoxia-ischemia is an important cause of brain injury in the newborn infant. Our purpose was to study magnetic resonance (MR) imaging changes in P7 rat brains submitted to permanent or reversible ischemia. Ischemia was induced by permanent electro-cauterization of the middle cerebral artery combined with a permanent or a transient (50 min) common carotid artery occlusion. The early events during ischemia and reperfusion were investigated by T2-weighted images (T2WI) at 1 and 3 h and by serial diffusion-weighted images (DWI) during 3 h in a 7 T magnet with a standard weighted diffusion sequence (b=1282.04 s mm(-2)) and a SEMS sequence. Within the first hour after MCA occlusion, the T2WI areas of contrast enhancement increased to a mean volume of 12.9+/-6.4%, a steady state still detected at 3 h after the ischemic onset (10.5+/-2.5%). Contrast enhancement in DWI increased as soon as 15 min of ischemia in all animals up to 50 min after CCA occlusion. In permanent ischemia, DWI abnormalities volume then increased more slowly from 50 min to 3 h after CCA occlusion (+25%, n=5). In reversible ischemia, the DWI abnormalities volume either moderately decreased and reached a plateau (-8.4%, n=4) or dramatically decreased (-53.0%, n=3). Both T2WI and DWI evidenced a "patchy" pattern of recovery as also shown on cresyl violet-stained sections. In contrast to the adult, early ischemic injury in P7 rat brains is detected as an increase in hyper-intensities both in T2WI and DWI. Our data indicate that reperfusion is able to block edema evolution after neonatal stroke and that early T2WI and more accurately DWI allow to distinguish between different patterns of injury in reversible ischemia.