美托洛尔抗高血压预防脑卒中的实验病理学研究

目的探讨抗高血压治疗预防脑卒中的形态学机制。方法采用易卒中型肾血管性高血压大鼠口服美托洛尔治疗，观察抗高血压治疗各级脑动脉和心室壁厚度的形态学改变。结果治疗组大鼠血压仅短期轻度低于未治疗的高血压对照组，但治疗组各级脑动脉损害和左心室肥厚明显改善，脑卒、中发生率也显著低于高血压对照组。结论美托洛尔抗高血压治疗预防脑卒中的效果，不单纯由血压下降决定，还与其具有保护脑血管和逆转心室肥厚等作用有关。     

易卒中型肾血管性高血压大鼠模型

用内径为0.30mm的银夹钳夹双侧肾动脉,复制出一种易卒中型肾血管性高血压大鼠模型,其血压峰值高且稳定在26.7kPa以上,并发生与人类高血压病类似的脑动脉损害:细小动脉纤维素样坏死、透明变性和微动脉瘤形成等,在此基础上,0.56的大鼠自发产生各种类型的脑卒中:脑梗塞、脑出血、蛛网膜下腔出血和混合性脑卒中。本文还着重将这种易卒中型肾血管性高血压大鼠与易卒中型自发性高血压大鼠作了比较。     

肾血管性高血压大鼠自发脑卒中与左心室肥厚的关系

目的探讨高血压个体脑卒中与左心室肥厚的关系。方法比较易卒中型肾血管性高血压大鼠发生与未有脑卒中的血压水平及左心室肥厚程度，观察经１０周抗高血压后，其脑卒中与血压和左心室肥厚的关系。结果脑卒中大鼠的血压水平及左心室肥厚程度比未卒中者更高。抗高血压后期，其血压水平与高血压对照组无显著性差异，但随着左心室肥厚的减轻，脑卒中率显著降低。结论左心室肥厚和脑卒中均为高血压的并发症，而前者不是后者的独立危险因素。减轻左心室肥厚的抗高血压治疗，即使降血压轻微，对预防脑卒中仍有意义     

易卒中肾血管性高血压大鼠血液流变学分析

目的 探讨易卒中肾血管性高血压大鼠血液流变学的变化。方法 运用双肾双夹法建立易卒中肾血管性高血压大鼠模型,常规饲养4个月后检测其血液流变学的变化。结果 术后4个月,易卒中肾血管性高血压大鼠的低切、中切、高切全血粘度、红细胞比积、低切全血还原粘度均显著高于正常血压大鼠。结论 易卒中肾血管性高血压大鼠具备了高血压病的血液流变学改变,是研究高血压性脑卒中的理想模型。     

肾血管性高血压大鼠脑动脉瘤模型的建立及发生机制初步探讨

目的 :探讨采用易卒中型肾血管性高血压大鼠建立脑动脉瘤模型。方法 :建立大鼠肾血管性高血压模型 ,再电凝切断左侧颈总动脉 ,然后用光镜和电镜观察右侧大脑前动脉和嗅动脉分叉处及附近的组织学改变。结果 :实验组在 2 0 /2 3只大鼠中可见瘤前、早期及进展期的动脉瘤改变 ,与人类囊状动脉瘤的病理改变相似。结论 :结扎一侧颈总动脉造成血流动力学改变的易卒中型肾血管性高血压大鼠可以作为较理想的脑动脉瘤模型。     

肾血管性高血压鼠与自发性高血压鼠脑血管损害的病理观察

为了解自发性高血压与肾血管性高血压所致脑血管病理损害的异同点。本研究用１５只自发性高血压大鼠（ＳＨＲ）和通过狭窄双侧肾动脉复制１５只肾血管性高血压大鼠（ＲＨＲ），分阶段动态观察两者脑内动脉管壁的病理变化。结果发现两种高血压动物的脑血管病理损害均是随着鼠龄增长及高血压的长期持续存在，由轻到重逐渐发展的，后期两者都有血管壁玻璃样变性，纤维素样坏死，自发性脑卒中出现。表明无论是原发性高血压还是继发性高血压，其所致的脑血管病理损害是相似的。     

高血压动脉硬化性混合性中风的实验病理学研究

用双肾双夹法复制易卒中型肾血管性高血压大鼠55只,肾动脉狭窄术后40周内自发脑卒中31只,其中单纯出血或缺血性中风20只(64.5％),混合性中风11只(35.5％)。混合性中风的大鼠脑内细小动脉的透明变性、纤维素样坏死、微动脉瘤形成及增生性反应等病变比单纯出血或缺血性中风者更为广泛、严重。表明高血压是混合性中风的重要病因,高血压性血管损害是其发病基础。本文还根据中风灶的大小将混合性中风进一步分型,并探讨了各型的发生机制。     

易卒中型肾血管性高血压大鼠脑微血管超微结构观察

动态观察了易卒中型肾血管性高血压大鼠在高血压不同时期和卒中急性期的脑微血管病变。发现高血压早期已有脑微血管损害,并随血压升高和持续时间延长而加重,至高血压晚期出现管腔狭窄,内皮细胞水肿。此时虽未发生卒中,但受损微血管周围的神经细胞已出现线粒体肿胀,内质网扩张等缺血缺氧表现。卒中时,管壁结构严重破坏,有的管腔闭塞。显示高血压时脑微血管病变在高血压动脉硬化性卒中发病中起重要作用。     

芦荟大黄素对易卒中型肾血管性高血压大鼠大脑中动脉重塑的影响

目的观察芦荟大黄素对易卒中型肾血管性高血压大鼠（RHRSP）大脑中动脉结构改变的影响。方法取造模成功的36只RHRSP大鼠随机分成3组：芦荟大黄素低剂量治疗组、高剂量治疗组和高血压组，另取10只作为假手术对照组（除不上银夹外，其余措施同高血压模型组）。测量收缩压（SBP）和血浆中ET水平。血管平滑肌细胞经α-平滑肌肌动蛋白（α-SM-actin）免疫组化染色后，应用计算机图像分析测量大脑中动脉血管外径、中膜厚度、管腔内径、壁腔比和中膜平滑肌面积。结果低剂量治疗组血浆ET水平显著低于高血压组（P〈0．05），而高剂量治疗组则稍低（P〉0．05）。镜下观察发现低剂量治疗组血管形态损害比高血压组轻，而高剂量治疗组则无减轻甚至更重。低剂量治疗组血管外径、管腔内径、中膜厚度均大于高血压组（P〈0．05），壁腔比则小于高血压组（P〈0．05）。低剂量治疗组中膜平滑肌面积比高血压组大（P〉0．05），但在高剂量治疗组反而缩小（P〉0．05）。结论低剂量芦荟大黄素可降低RHRSP血浆ET水平，改善血管内皮功能，具有一定的改善血管重塑的作用。     

高血压对大鼠脑动脉平滑肌细胞表型改变影响的研究

探讨高血压对脑动脉平滑肌细胞 (SMC)表型改变的影响。　　方法　将SD大鼠造成肾性高血压 ,并分为正常组和高血压 6、9及 1 2周组。各组动物脑标本分别做HE染色和α -Actin及增殖细胞核抗原 (PCNA)免疫组化染色。比较各组HE染色标本的动脉内径和管壁厚度的比值 ;对各组动物平滑肌细胞α -Actin和PCNA染色阳性和阴性的动脉进行比较。　　结果　随高血压时间延长 ,脑动脉硬化性改变逐渐明显 ;平滑肌PCNA染色阳性的脑动脉逐渐增多。　　结论　本实验提示高血压有可能促进颅内动脉SMC由收缩型向合成型转变。     

Mechanism of cerebral vasospasm following subarachnoid hemorrhage in monkeys.

This paper reviews our recent studies on the mechanism of cerebral vasospasm following subarachnoid hemorrhage (SAH) in monkeys. Middle cerebral artery (MCA) vasospasm was maximal at 7 days, resolving by 14 days, and absent at 28 days after SAH. Arterial fibrosis was not detected during vasospasm, although there was intimal hyperplasia with fibrosis 28 days after SAH. On scanning electron microscopy, smooth muscle cells from vasospastic arteries had corrugated cell membranes and appeared similar to cells contracted pharmacologically, suggesting that vasospastic smooth muscle is contracted. Morphometric analysis of arteries obtained 7 days after SAH showed no significant increases in arterial wall area of vasospastic arteries compared with normal MCAs. The results suggest vasospasm in monkeys is not due to hypertrophy, hyperplasia, or fibrosis in the arterial wall. Vasospasm may be mainly vascular smooth muscle contraction, which damages the arterial wall, leading to secondary structural changes in the arterial wall which occur after angiographic vasospasm.     

Is the spontaneously hypertensive stroke prone rat a pertinent model of sub cortical ischemic stroke? A systematic review

The spontaneously hypertensive stroke prone rat is best known as an inducible model of large artery stroke. Spontaneous strokes and stroke propensity in the spontaneously hypertensive stroke prone rat are less well characterized; however, could be relevant to human lacunar stroke. We systematically reviewed the literature to assess the brain tissue and small vessel pathology underlying the spontaneous strokes of the spontaneously hypertensive stroke prone rat. We searched systematically three online databases from 1970 to May 2010; excluded duplicates, reviews, and articles describing the consequences of induced middle cerebral artery occlusion or noncerebral pathology; and recorded data describing brain region and the vessels examined, number of animals, age, dietary salt intake, vascular and tissue abnormalities. Among 102 relevant studies, animals sacrificed after developing stroke-like symptoms displayed arteriolar wall thickening, subcortical lesions, enlarged perivascular spaces and cortical infarcts and hemorrhages. Histopathology, proteomics and imaging studies suggested that the changes not due simply to hypertension. There may be susceptibility to endothelial permeability increase that precedes arteriolar wall thickening, degeneration and perivascular tissue changes; systemic inflammation may also precede cerebrovascular changes. There were very few data on venules or tissue changes before hypertension. The spontaneously hypertensive stroke prone rat shows similar features to human lacunar stroke and may be a good spontaneous model of this complex human disorder. Further studies should focus on structural changes at early ages and genetics to identify factors that predispose to vascular and brain damage.     

Effects of aging on the structural and permeability characteristics of cerebrovasculature in normotensive and hypertensive strains of rats

Summary This study demonstrates that markedly different patterns of age-related changes in blood pressure and body weight occur among normotensive Wistar-Kyoto (WKY) and Sprague-Dawley (SD) rats and spontaneously hypertensive rats (SHR). In addition, a variety of age-related structural alterations occurred in the walls of arterioles, capillaries, and venules of the frontal cortex. These changes include: (1) an increase in the thickness of the vascular wall by deposits of collagen and basal lamina which, in some cases, extended into the surrounding neuropil; (2) the presence of a flocculent material in the adventitia of intracerebral arterioles; (3) vesicular inclusions in perivascular macrophages, pericytes and smooth muscle cells which were labelled with i.v. administered horseradish peroxidase (HRP); (4) fragmentation of smooth muscle cells; and (5) accumulation of lipofuscin-like pigments in perivascular glial processes. The hypertensive rats exhibited these changes, but they were more advanced and more widely distributed throughout the cerebral cortex. The aged hypertensive rats occasionally had large bundles of 10 nm diameter, intermediate filaments in the endothelial cells. Whereas no change in blood-brain barrier permeability to HRP was observed in the aged normotensive rats, all age groups of the hypertensive rats exhibited increased permeability to HRP in the initial segment of penetrating arterioles in laminae I and II of the cerebral cortex.     

不同时间窗大鼠脑血栓溶解治疗后梗死体积和脑电图的研究

目的：研究不同时间窗脑血栓溶解治疗后脑电变化与梗死体积的关系。方法：应用肾血管性高血压大鼠,用光化学法制成一侧大脑中动脉闭塞模型,在血栓形成后不同时间应用尿激酶静脉溶栓,观察脑电图变化与梗死体积的大小。结果：缺血２小时之内实行溶栓治疗,可缩小梗死性。ＭＣＡＯ３０分钟后溶栓复流后,ＥＥＧ有改善,一小时后慢波减少,２４小时ＥＥＧ可恢复到基本正常。     

Rupture of the internal elastic lamina and vascular fragility in stroke-prone spontaneously hypertensive rats

We studied a possible relation between stroke and an enhanced susceptibility to rupture of the arterial internal elastic lamina by comparing stroke-prone spontaneously hypertensive rats with spontaneously hypertensive rats, which have a very low incidence of stroke. We quantified interruptions in the internal elastic lamina in certain arteries and studied the effect of beta-aminopropionitrile, an inhibitor of cross-link formation in collagen and elastic fibers, on rupture of the internal elastic lamina and on mortality in these two substrains. To eliminate any influence of higher blood pressure in the stroke-prone rats on the parameters studied, we used antihypertensive treatment to obtain equivalent blood pressures in the two substrains. Results showed that stroke sensitivity was associated with an enhanced early spontaneous rupture of the internal elastic lamina in the caudal artery, an increased susceptibility to beta-aminopropionitrile-induced rupture of the internal elastic lamina, and earlier mortality, mainly from aortic rupture, under beta-aminopropionitrile treatment. These findings suggest that stroke-prone rats have an enhanced minor connective tissue defect that is expressed by rupture of the internal elastic lamina and may be related, at least in part, to their greater vascular fragility and increased susceptibility to stroke.     

人工寒潮促发脑卒中的实验研究

目的　探索建立人工寒潮环境 ;探讨人工寒潮与脑卒中的关系。方法　观测用经改装的冷藏柜及人工气候箱模拟寒潮时所需条件及达标情况 ;分别将复制成功的易卒中型肾血管性高血压大鼠 (RHRSP)及正常大鼠置于人工寒潮环境中 ,观察大鼠的血压波动、脑血管病变及脑卒中的发生情况。结果　冷藏柜与人工气候箱均能模拟寒潮 ,后者除能控制温度外同时能控制相对湿度 ;人工寒潮来临时RHRSP组大鼠血压波动大、自发性脑卒中明显增多 ,与对照组比较有明显差异 (P <0 0 5 )。结论　人工气候箱较冷藏柜能更好模拟寒潮 ,人工模拟寒潮克服了季节限制且一致性好、易重复 ;人工寒潮可以使RHRSP发生脑卒中 ,可较好模拟气温骤降 (自然寒潮 )时的脑卒中 ,为进一步研究寒潮诱发脑卒中的机制提供了条件     

亚低温对脑缺血区P53蛋白表达的影响

目的　在尿激酶溶解大鼠脑血栓治疗中,研究亚低温对溶栓复流后大脑中动脉缺血区 Ｐ５３蛋白表达的影响。方法　应用肾血管性高血压大鼠（ Ｒ Ｈ Ｒ Ｓ Ｐ）,用光化学法制成一侧大脑中动脉闭塞（ Ｍ Ｃ Ａ Ｏ）模型,在血栓形成后 ０．５ｈ 应用尿激酶静脉溶栓复流后,用免疫组织化学的方法研究 Ｐ５３蛋白的表达。结果　亚低温组 Ｐ５３蛋白的表达,明显弱于正常体温组。结论　亚低温降低脑缺血区域的 Ｐ５３蛋白的表达,可能是亚低温产生脑保护的机制之一。     

实验性高血压对脑血流自动调节功能影响的动态观察

目的　动态观察高血压对脑血流自动调节下限的影响 ,及其与脑血管病理形态改变的关系。方法　选用 80只易卒中型肾血管性高血压大鼠 (RHRSP) ,在术后不同的时间点 ,利用临界关闭压测定脑血流自动调节下限 (LLCA) ,并动脉插管测定血压和定量分析脑血管的形态变化 ,分别与正常血压对照组 (80只 )的结果进行比较。结果　RHRSP组的LLCA术后第 6周开始升高 ,第 10周后明显高于对照组 (P <0 0 5 ) ,基本稳定于 110mmHg左右。多元回归分析发现 ,LLCA的升高主要与平均动脉压呈正相关 (r=0 96 8,P <0 0 5 ) ,与脑内微动脉的中膜厚度呈正相关 (r=0 94 0 ,P <0 0 5 )。并且LLCA的变化在平均动脉压改变的中间过程最明显 ,而于平均动脉压轻度和重度升高时变化不大 ,呈“S”形改变 (R2 =0 970 1,P <0 0 5 )。结论　高血压LLCA上移主要与平均动脉压有关 ,是脑内微动脉中膜增厚的体现 ,于血压升高中期改变最为明显。     

银夹形状对肾血管性高血压大鼠远期血压及并发症的影响

观察不同形状银夹对肾血管性高血压大鼠远期血压及并发症的影响。　　方法　用内径均为 0 3mm的环形和槽形银夹分别复制双肾双夹型肾血管性高血压大鼠 ,记录两组大鼠在肾动脉狭窄术后 3 0周内的血压水平、自发脑卒中率和心肌梗塞率。　　结果　肾动脉狭窄术后 1～1 4周内 ,两组血压无显著性差异 ,1 4周后环形银夹组血压高于槽形银夹组 ,3 0周内自发脑卒中率和心肌梗塞率也高于槽形银夹组。　　结论　用环形银夹复制的双肾双夹型肾血管性高血压大鼠模型 ,更适用于高血压性心、脑并发症的研究