内皮素和自由基在脑缺血中的相互作用

本文在建立兔ＭＣＡＯ模型的基础上，用放免法测脑组织和血浆中内皮素（ＥＴ）的含量，同时用ＴＢＡ法测定脑组织中过氧化脂质（ＬＰＯ）含量。兔３６只，随机分三组，对照组（假手术），脑缺血后４ｈ，２４ｈ组，每组１２只。结果发现脑缺血后ＥＴ和ＬＰＯ之间呈明显的正相关（Ｐ＜０．００１），且随缺血后时间的延长而递增（Ｐ＜０．０１），用相关回归分析发现，脑组织ＥＴ和ＬＰＯ均显著高于对照组（Ｐ＜０．０５），结果说明脑     

NO代谢变化对缺血性脑组织内皮素产生的影响

在兔大脑中动脉阻断（ＭＣＡｏ）型局灶脑缺血前后分别应用外源性一氧化氮合成酶（ＮＯＳ）抑制剂Ｌ－ＮＮＡ和ＮＯ合成底物Ｌ－ａｒｇｉｎｉｎｅ，观察缺血４小时后脑组织内皮素（ＥＴ）含量的变化。结果发现Ｌ－ＮＮＡ组较缺血对照组脑组织ＥＴ含量明显增多（１２６２．９±３８７．６ｖｓ７８９．３±１８８．４ｐｇ／ｍｇ·ｐｒｏ，Ｐ值＜０．０１），脑水肿显著；而Ｌ－ａｒｇｉｎｉｎｅ用药组脑组织ＥＴ含量较缺血对照组明显减少（Ｐ值＜０．０５），且脑水肿减轻。本研究提示ＮＯ能抑制缺血脑组织ＥＴ的产生。ＮＯ对脑缺血影响可能与此途径有关。     

MCA—O鼠血浆内皮素含量变化及地塞米松对其的影响

目的探讨缺血性脑损害与血浆内皮素（ＥＴ）变化之间的关系，以及地塞米松（Ｄｍ）治疗效应的影响。方法采用线栓法制作一侧大脑中动脉栓塞（ＭＣＡ－Ｏ）大鼠模型；脑缺血再灌流组（ＩＲ）、地塞米松治疗组（ＩＲ＋Ｄｍ）于造型成功后１、６、２４、４８、９６ｈ采血２ｍｌ，取血浆；采用放免法测定ＥＴ。结果（１）ＩＲ、生理盐水对照组（ＩＲ＋ＮＳ）血浆ＥＴ含量显著增高（Ｐ＜０．０１，Ｐ＜０．００１）；（２）ＩＲ＋Ｄｍ组血浆ＥＴ含量较ＩＲ＋ＮＳ组显著降低（Ｐ＜０．０５，Ｐ＜０．０１）；同时脑缺血性病理损害明显减轻。结论（１）鼠血浆ＥＴ含量变化与脑缺血性损害病生机制密切相关；（２）地塞米松的应用对缺血脑组织有保护作用     

大鼠局部脑缺血再灌流的实验研究

采用大鼠局部脑缺血再灌流模型，研究了大鼠脑缺血６ｈ、９ｈ和缺血６ｈ再灌流３ｈ脑梗塞体积，脑含水量，能量代谢，丙二醛（ＭＤＡ）和超氧化物歧化酶（ＳＯＤ）的变化。结果：脑缺血６ｈ、９ｈ可以造成严重的脑梗塞和脑水肿，ＡＴＰ含量和ＳＯＤ活性显著降低，乳酸和ＭＤＡ含量显著增加，和对照组相比均有显著差异（Ｐ＜０．０５或Ｐ＜０．００１）。再灌组和缺血两组比较，脑梗塞体积，脑水肿无明显差别（Ｐ＞０．０５），ＡＴＰ、乳酸、ＳＯＤ和ＭＤＡ均有不程度的改善。提示，大鼠局部脑缺血超过６ｈ可造成严重的脑损伤，并随缺血时间的再延长，脑损伤变化趋于平缓。再灌后，脑损伤未见明显加重。     

脑缺血和再灌注后脑组织内皮素－1基因表达及丹参的影响

为研究脑缺血和再灌注后脑组织内皮素－１（ＥＴ－１）基因表达的变化以及丹参对它的影响，采用线栓法制成大鼠大脑中动脉缺血和再灌注模型，并用地高辛精标记ＥＴ－１基因进行原位杂交。结果显示，缺血组（缺血２４ｈ）和再灌注组（缺血１．５ｈ再灌注２４ｈ）缺血侧皮层及尾壳核ＥＴ－１基因表达均显著高于健侧相应的脑区（Ｐ＜０．０１，Ｐ＜０．０５），经丹参治疗后缺血或再灌注鼠缺血侧皮层及尾壳核ＥＴ－１基因表达均显著低于生理盐水（ＮＳ）对照组（Ｐ＜０．０５，Ｐ＜０．０１），但仍比健侧脑区显著增高。本实验表明，缺血和再灌注均可诱导脑组织ＥＴ－１基因的异常表达，进一步加重缺血和再灌注引起的脑损伤，丹参对缺血诱导的ＥＴ－１基因表达有部分抑制作用，这可能是丹参防治缺血性脑血管病的分子机理之一。     

局灶性脑缺血后脑内髓过氧化物酶活性观察

目的　探讨局灶性脑缺血后脑组织髓过氧化物酶（ＭＰＯ） 活性的测定方法,以及与缺血性损害的关系。方法　采用新型小鼠大脑中动脉线栓模型,检测不同缺血时间组梗塞体积及ＭＰＯ活性。结果　缺血１ ｈ 后再灌注２３ ｈ 组（ｔＭＣＡＯ）缺血灶体积明显小于缺血２４ ｈ 组（ｐＭＣＡＯ）;ＭＰＯ活性在各缺血组缺血侧明显高于对照侧和对照组（ Ｐ＜ ０－０５）,ｐＭＣＡＯ 组缺血侧基底节区ＭＰＯ 活性显著高于ｔＭＣＡＯ 组（ Ｐ＜ ０－０５） ,而两组缺血皮质区ＭＰＯ 活性则无显著差异。结论　本研究建立了局灶性脑缺血的ＭＰＯ活性测定方法,证明ＭＰＯ活性与缺血损伤间具有一定关系。     

沙土鼠脑缺血后脑组织匀浆及血浆中SOD,MDA的含量改变及其意义

１１２只沙土鼠分为正常组、假手术组、手术组，成功地建立了沙土鼠脑缺血模型，并测定了脑组织匀浆及血浆中超氧化物歧化酶（ＳＯＤ）、丙二醛（ＭＤＡ）的含量，结果示：缺血右半球ＭＤＡ值较同体左半球ＭＤＡ值有明显增高（Ｐ＜０．０５），说明脑缺血后脑组织内确曾发生明显的脂质过氧化反应，提示自由基对缺血性脑损害的形成有一定作用。缺血右半球ＳＯＤ活力较同体左半球下降（Ｐ＜０．０５）。整个实验中，脑缺血后血浆ＳＯＤ、ＭＤＡ均无明显变化。     

脑梗塞患者血浆和脑脊液中内皮素-1、降钙素基因相关肽含量的研究

用放免法检测４０例脑梗塞患者脑脊液和不同病期血浆中内皮素－１（ＥＴ－１）、降钙素基因相关肽（ＣＧＲＰ）的含量并与对照组比较。结果：脑梗塞患者脑脊液中ＥＴ－１含量无明显改变（Ｐ＞０．０５），ＣＧＲＰ含量显著降低（Ｐ＜０．０１）。发病２周内血浆ＥＴ－１含量明显高于对照组（Ｐ＜０．０５），而发病４周内ＣＧＲＰ值却显著低于对照组（Ｐ＜０．０１）。患者是否伴高血压、神经功能缺损轻重、梗塞灶大小对血浆ＥＴ－１和ＣＧＲＰ含量均无明显影响。     

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。     

盐酸氟桂利嗪对沙土鼠脑缺血后血浆降钙素基因相关肽和P物质含量的影响

目的 测定右侧的脑缺血蒙古种沙土鼠血浆钙素基因相关肽（ＣＧＲＰ）及Ｐ物质（ＳＰ）含量变化并观察盐酸氟桂利嗪对其影响,进一步探讨盐酸氟桂利嗪对缺血后神经细胞保护作用及可能机制。方法 用线扎法制作沙土鼠右侧半球前脑缺血模型,对各组进行神经功能缺失评分。采用放射免疫方法（ＲＩＡ）测定各组沙土鼠血浆ＣＧＲＰ、ＳＰ含量。结果 药物治疗组ＣＧＲＰ、ＳＰ含量与缺血对照组比较有显著差异（Ｐ〈０．０１）,与假手术组与正常对照组比较没有显著差异（Ｐ〉０．０５）。缺血对照组ＣＧＲＰ、ＳＰ含量与假手术组及正常对照组比较有显著差异（Ｐ〈０．０１）。假手术组ＣＧＲＰ、ＳＰ含量与正常对照组比较没有显著差异（Ｐ〉０．０５）。结论 ＣＧＲＰ、ＳＰ参与了脑缺血的病理生理过程,盐酸氟桂利嗪是一种有效的钙离子拮抗剂,通过对ＣＧＲＰ、ＳＰ含量调节,是其     

脑缺血后脑细胞线粒体LPO、SOD的变化

我们利用兔MCAO模型,分别测定脑缺血后4h(I_4)、24h(I_(24))脑组织的H_2o、Na~ 、Ca~(2 )、LPO,SOD以及线粒体的LPO,SOD,经与对照组(包括假手术和正常对照)对比,结果发现脑缺血后脑组织H_2o、Na~ 、C_a~(2 )LPO及线粒体LPO均明显增加,而SOD活性变化则相反地降低。结果提示脑缺血后脑细胞线粒体的LPO含量增加,而SOD活性则下降,说明脑缺血后线粒体产生的自由基参与了脑缺血脑损伤机制。     

脑缺血后脑组织和血浆中内皮素的变化

建立兔大脑中动脉阻断(MCAO)脑缺血模型。将48只兔随机分为四组:C(正常对照和假手术对照组)和脑缺血 I_2、I_4、I_(24)组,每组12只,测脑 H_2O、Na~+、K~+、Ca~(2+)、内皮素(ET)和血浆 ET。结果示脑缺血侧脑皮质和血浆中 ET 含量显著高于对照组(P<0.001),且随时相递增(P<0.01),ET与脑 H_2O 含量之间呈显著正相关(P<0.05),提示 ET 可能参与脑缺血、脑水肿的发生发展。     

局灶脑缺血脑水肿时强啡肽的含量变化

应用兔大脑中动脉阻断(MCAO)局灶脑缺血模型,将实验动物随机分成4组:对照组C、脑缺血后2h、4h、24h(I_2、I_4、I_(21))组。放射免疫法测定脑组织和血浆中强啡肽(Dynorphin,Dyn)含量的时相变化,同时测脑组织H_2O、Na~+含量。结果发现MCAO后脑组织和血浆Dyn含量显增,且随时相递增,并与脑组织H_2O、Na~+变化呈正相关,提示Dyn可能参与脑缺血、脑水肿的发生发展。     

Preconditioning with a TLR2 specific ligand increases resistance to cerebral ischemia/reperfusion injury

The brain's resistance to ischemic injury can be transiently augmented by prior exposure to a sub-lethal stress stimulus, i.e. preconditioning. It has been reported that Toll-like receptors (TLRs) are involved in the preconditioning-induced protective effect against ischemic brain injury. In this study, we investigated the effect of preconditioning with a TLR2 specific ligand, Pam3CSK4, on focal cerebral ischemia/reperfusion (I/R) injury in mice. Pam3CSK4 was administered systemically 24 h before the mice were subjected to focal cerebral ischemia (1 h) followed by reperfusion. Cerebral infarct size was determined, blood brain barrier (BBB) permeability was evaluated, and expression of tight-junction proteins were examined after focal cerebral I/R. Results showed that pre-treatment with Pam3CSK significantly reduced brain infarct size (1.9+/-0.5% vs 9.4+/-2.2%) compared with the untreated I/R group. Pam3CSK4 pre-treatment also significantly reduced acute mortality (4.3% vs 24.2%), preserved neurological function (8.22+/-0.64 vs 3.91+/-0.57), and attenuated brain edema (84.61+/-0.08% vs 85.29+/-0.09%) after cerebral I/R. In addition, Pam3CSK4 pre-treatment preserved BBB function as evidenced by decreased leakage of serum albumin (0.528+/-0.026 vs 0.771+/-0.059) and Evans Blue (9.23+/-0.72 mug/mg vs 12.56+/-0.65 mug/mg) into brain tissue. Pam3CSK4 pre-treatment also attenuated the loss of the tight junction protein occludin in response to brain I/R injury. These results suggest that TLR2 is a new target of ischemic preconditioning in the brain and preconditioning with a TLR2 specific ligand will protect the brain from I/R injury.     

重组人促红细胞生成素对大鼠局灶性脑缺血再灌注损伤的保护作用

目的 探讨重组人促红细胞生成素(EPO)对大鼠局灶性脑缺血再灌注损伤所致炎性反应的保护机制。方法采用线拴法制备大鼠局灶性大脑中动脉缺血再灌注模型,应用TTC染色法、干湿重法、常规HE染色法观察EPO治疗前后再灌注24h脑梗死体积、脑组织含水量以及组织学变化,应用RT- PCR方法检测EPO治疗前后再灌注lh、3h、6h、12 h、24h、72 h缺血侧脑皮质IL-1β、TNF-α基因表达的变化。结果与假手术组相比,EPO可显著缩小缺血再灌注24h所致的脑梗死体积(P＜0.01),降低梗死侧脑组织含水量(P＜0.01),减轻病理学变化。缺血再灌注各时相点缺血侧皮层IL -lβ mRNA和TNF -α mRNA表达均显著上调(P＜0.01),12 h达高峰。EPO治疗后lh、3h、6h缺血侧皮层IL - 13 mRNA表达显著下降,与病理组相应时间点相比,分别降低了63％、55％和84％(P＜0.01)。EPO治疗后lh、3h、6h缺血侧皮层TNF -α mRNA表达亦显著下降,与病理组相应时间点相比,分别降低了75％、76％和95％（P＜0.01）。结论EPO可能通过抑制IL - 1β、TNF-α的基因表达,降低缺血再灌注的炎性反应损伤而改善脑组织的结构和功能。     

Reduction of ischemic brain injury by anti-P-selectin monoclonal antibody after permanent middle cerebral artery occlusion in rat.

The selectin family of adhesion molecules is involved in adhesion of leukocyte to microcirculatory system and the transmigration into brain parenchyma. Although the role of P-selectin may be important in the pathogenesis of brain ischemia, a possible protective effect on ischemic brain injury by blocking P-selectin has not been reported. We have examined the effects of a novel anti-P-selectin antibody on ischemic brain injury after 24 h of permanent middle cerebral artery occlusion (MCAO) in rat. Male Wistar rats were subjected to MCAO by an insertion of a silicone rubber cylinder for 24 h. Anti-rat P-selectin monoclonal antibody, ARP 2-4, was injected intravenously at a dose of 1 mg kg-1 at 5 min before the induction of MCAO. Control animals received the same volume of vehicle solution. Regional cerebral blood flow (rCBF) was measured immediately after and at 8 h of MCAO. At decapitation of rats at 24 h of permanent MCAO, infarct size was compared between the antibody and vehicle treated group. In addition, immunohistochemistry for leukocyte infiltration and HSP72, and histochemistry for TUNEL were also, compared. Pretreatment with ARP 2-4 improved rCBF at 8 h of MCAO (55.4% +/- 11.7% of control, n = 5) as compared to vehicle group (24.2% +/- 11.8%, n = 5, p < 0.02). Although leukocyte infiltration was not normally detected by monoclonal antibodies for CD11a and CD18, it became remarkably evident at 1 day of MCAO. Although HSP72 and TUNEL were not also detected in sham control brains, they were induced in neurons of the MCA area at 1 day of MCAO. Treatment with ARP 2-4 significantly reduced the numbers of leukocyte and neurons with positive HSP72 and TUNEL stainings. These results demonstrated that an administration of a monoclonal antibody against P-selectin improved rCBF, and attenuated infarct size that was associated with reduction of leukocyte infiltration. Furthermore, treatment with the antibody reduced both HSP72 and TUNEL stainings. These data suggest an important role of P-selectin in ischemic brain damage, and a future therapeutic potential to human stroke patients.     

NADPH-oxidase activity is elevated in penumbral and non-ischemic cerebral arteries following stroke

Reactive oxygen species play a role in neuronal damage following cerebral ischemia-reperfusion. We tested whether activity of the superoxide-generating enzyme, NADPH-oxidase, is enhanced in cerebral arteries within, adjacent and distant from the ischemic core. The right middle cerebral artery (MCA) of conscious rats was temporarily occluded by perivascular injection of endothelin-1 to induce stroke (ET-1; n=19). Control rats were injected with saline (n=9). At 24 h or 72 h post-administration of ET-1, the MCA and its branches within the ipsilateral penumbra and infarcted core, corresponding arteries in the contralateral hemisphere, and basilar artery were excised. Anatomically similar arteries were excised from saline-injected rats. At 24 h after stroke, NADPH-stimulated superoxide production by arteries from the infarcted core did not differ from levels generated by arteries from control rats, whereas levels were significantly lower 72 h after stroke. However, at both time points after stroke, superoxide production by arteries from the ischemic penumbra was 8-fold greater than levels generated by arteries from control rats. Surprisingly, even in the non-ischemic arteries from the contralateral hemisphere and in the basilar artery, superoxide production was increased approximately 4- to 6-fold at 24 h, but had returned to normal 72 h after stroke. The NADPH-oxidase inhibitor, diphenyleneiodonium, virtually abolished superoxide production by all arteries. Thus, the activity of NADPH-oxidase is enhanced in cerebral arteries from the ischemic penumbra at 24 h and 72 h following cerebral ischemia. Additionally, NADPH-oxidase activity is temporarily enhanced after cerebral ischemia within arteries from non-ischemic parts of the brain.     

白介素-8在局灶性脑缺血大鼠脑组织及血清中的表达及地塞米松对其的影响

目的探讨白介素(IL)-8在局灶性脑缺血大鼠脑组织及血清中的表达及地塞米松对其的影响。方法实验大鼠随机分为空白对照组、假手术组、缺血组及地塞米松组,后两组又各分为术后1h、2h、4h、8h、12h、24h、48h、72h组;每组12只。采用线栓法制备大鼠大脑中动脉栓塞模型;在相应的时间点应用ELISA法检测各组脑组织及血清中IL-8的水平。结果缺血组与地塞米松组脑组织及血清中IL-8水平于缺血1h后逐渐升高,后于24h及4h达高峰;缺血组与地塞米松组脑组织及血清中IL-8水平各时间点又低于空白对照组与假手术组(均P<0.05),地塞米松组又低于缺血组(均P<0.05)。结论局灶性脑缺血大鼠脑组织及血清中IL-8表达与时间关系密切;地塞米松可明显抑制局灶性脑缺血大鼠脑组织中炎性反应。     

大鼠急性脑缺血时尼莫地平对内皮衍生因子的影响

尼莫地平是一种钙离子拮抗剂，现巳用于急性脑缺血的治疗。本文通过观察大鼠急性脑缺血模型及假手术组循环中及脑组织内一氧化氮（NO）、内皮素（ET1）水平，并观察尼莫地平对大鼠脑缺血模型循环中及脑组织的NO、ET1水平的影响，发现模型组循环中的NO水平较假手术组有下降趋势，但无明显统计学差异（P＞0．05），ET1的水平较假手术组显著升高（P＞0．05）;脑组织中NO、ET1含量均较假手术组显著升高（P＜0．05）。尼莫地平具有显著升高急性脑缺血大鼠循环中NO，显著降低循环中ET1，显著降低脑组织中NO、ET1的水平，说明尼莫地平具有促进脑缺血时大鼠的脑部供血，保护由于脑缺血引起的脑组织损害。