尼维地平对大鼠局灶脑缺血的治疗作用（摘要）

尼维地平对大鼠局灶脑缺血的治疗作用（摘要）李毅平，朱廷吉，王长坤，索敬贤，张雅洁，川村伸悟，安井信之尼维地干（Ｎｉｌｖａｄｉｐｉｎｅ）是新研制的二羟吡啶类钙离子拮抗剂，具有时血管平滑肌亲和力高和作用时间长的特点。我们已证实大鼠局灶脑缺血后立即应用Ｎｉ...     

光化学大鼠大脑中动脉血栓形成模型的静脉溶栓治疗研究

目的　探讨经静脉溶栓治疗脑梗塞的价值和给药方法。方法　光化学大鼠大脑中动脉（ Ｍ Ｃ Ａ）血栓形成后 １ｈ,治疗组 １５ 只静脉注射尿激酶（ Ｕ Ｋ）,血栓形成后 ２４ｈ 行神经功能评分,７２ｈ Ｍ Ｒ检查后处死行病理检查。结果　治疗组 ８６．６７％ 的血栓在 １～３ｈ 内溶开,对照组均无溶开。治疗组的神经功能比对照组好,梗塞灶体积小。结论　大鼠 Ｍ Ｃ Ａ 血栓形成后 １ｈ 经静脉 Ｕ Ｋ 溶栓可改善神经功能,减少梗塞体积,最小有效剂量为 ２．５×１０４ Ｕ／ｋｇ,最大剂量 ７．５×１０４ Ｕ／ｋｇ,不增加颅内出血率。     

人工合成E-选择素治疗大鼠局灶脑缺血再灌注损伤的探讨

目的：探讨新的药物治疗脑缺血再灌注损伤。方法：用人工合成 Ｅ－选择素 ２ｍｇ·ｋｇ－１或 １０ ｍｇ·ｋｇ－１溶解于生理盐水中,静脉注入自发性高血压大鼠永久左侧大脑中动脉／颈总动脉（ＭＣＡ／ＣＣＡ）闭塞或ＭＣＡ／ＣＣＡ闭塞２ｈ后ＣＣＡ再灌注模型中。２４ｈ后,脑梗死体积用计算机扫描计算。结果：在永久性ＭＣＡ／ＣＣＡ闭死组中脑梗死体积没有差别,在ＭＣＡ／ＣＣＡ闭死后ＣＣＡ再灌注组中脑梗死体积有意义地缩小（Ｐ＜０．０１）。结论：Ｅ－选择素能够有效地减少大鼠脑缺血再灌注损伤。     

抗白细胞药物在保护大鼠局灶性脑缺血中的时间窗研究

目的 研究抗白细胞药物，环磷酰胺，氯化奎宁，秋水仙碱在保护大鼠局灶性脑缺血中的时间窗问题。方法 用线栓法建立大鼠大脑中动脉区缺血再灌注模型，检测于栓塞后１ｈ，６ｈ，１２ｈ，２４ｈ四个不同的时间窗应用抗白细胞药物对大鼠局灶性脑缺血后梗塞体积及梗塞区小胶质细胞数的影响。结果 抗白细胞药物于１ｈ６ｈ，１２ｈ三个时间窗给药，其疗效相似（Ｐ〉０．０５），显著优于２４ｈ给药组和对照组（Ｐ〈０．０１），而２４ｈ     

黄芪皂甙对大鼠MCAO／IR模型氨基酸含量的影响——活体微透析研究

采用大鼠插线法缺血１小时再灌流２小时模型，比较对照组和黄芪皂甙（ＡＳＳ）组在缺血／再灌流时氨基酸和含水量的变化。结果：（１）脑缺血６０分钟时上升到峰值浓度，随后很快下降，再灌流２小时内未见回升；（２）ＡＳＳ组谷氨酸（Ｇｌｕ）峰值浓度下降了１３．２％，但未见统计学差异；（３）黄芪皂甙显著降低了梗塞灶内脑组织含水量。认为尽管ＡＳＳ未能使Ｇｌｕ产生明显下降，但能降低梗塞灶含水量，说明ＡＳＳ的脑保护作用可能是通过其它途径实现的。     

人工合成E-选择素治疗鼠局灶脑缺血再灌注损伤的探讨

目的 探讨新的药物有效地治疗急性期脑缺血再灌注损伤。方法 用人工合成Ｅ－ｓｅｌｅｃｔｉｎ Ｌｅｃｔｉｎ Ｄｏｍａｉｎ（以下Ｅ－选择素）Ｎ－末端２３－３０氨基酸残基合成的寡肽（Ｏｌｉｇｏｐｅｐｔｉｄｅ）２ｍｇ／ｋｇ或１０ｍｇ／ｋｇ溶解于生理盐水中,静脉注入自发性高血压大鼠（ＳＨＲ）永久性大脑中动脉／颈总动脉硬化（ＭＣＡ／ＣＣＡ）闭塞或ＭＣＡ／ＣＣＡ闭塞２小时后ＣＣＡ再灌注的模型中。２４小时后,脑梗死体积用计算机扫描计算。结果 在永久性ＭＣＡ／ＣＣＡ闭塞组中脑梗死体积没有差别,在ＭＣＡ／ＣＣＡ闭塞后ＣＣＡ再灌注组中脑梗死体积显著缩小（Ｐ〈０．０１）。结论 Ｅ－选择素能够有效地减少大鼠脑缺血再灌注损伤。     

D1和D2受体拮抗剂对乙灶性脑缺血梗塞体积及脑血流的影响

目的 研究多巴胺（ＤＡ）Ｄ１受体拮抗剂ＳＣＨ－２３３９０和Ｄ２受体拮抗剂Ｅｔｉｃｌｏｐｒｉｄｅ对可逆性乙灶性脑缺血梗塞体积及皮层半暗带脑血流的影响。方法 采用激光多普勒脑血流计测量大鼠可逆性乙灶性脑缺血各时相皮层半暗带脑血流,并于缺血后２４小时断头取脑切片,ＴＴＣ染色,计算机图样分析系统测量脑梗塞体积。结果 Ｄ１受体拮抗剂ＳＣＨ－２３３９０可明显缩小局灶性脑缺血梗塞体积,改善缺血期各时相皮层半暗带     

外伤性脑梗塞

目的对不同部位、不同面积的外伤性脑梗塞进行有区别的治疗，以提高治疗效果。方法灶状梗塞病人给予内科综合治疗，重症颅脑损伤合并大血管区梗塞者，行手术清除血肿、颞肌下减压及内科药物治疗。结果灶状梗塞组中，儿童患者１４～２８天症状全部消失，青壮年组（２２例）治愈１４例，轻瘫６例，失语２例。大血管区梗塞组（１１例）死亡６例，中到重度残３例，植物生存１例，良好１例。结论外伤性脑梗塞预后主要取决于梗塞灶内残存脑血流量。重度颅脑损伤合并大血管区梗塞者，死亡率明显高于无梗塞者，且致残率较高，治疗中应予以高度重视     

高血压在局部脑梗塞边缘区和镜区脑超微结构的动态改变中的意义

本文实验发现双肾双夹肾血管性高血压大鼠（ＲＨＲ）在大脑中动脉闭塞（ＭＣＡＯ）后１～７天，梗塞灶边缘区有脑微血栓形成，ＭＣＡＯ后３天对侧半球的相应区（镜区）有较明显的微血管变形和星形细胞足突水肿改变，说明ＲＨＲ与正常的ＳＤ鼠在局灶脑梗塞后的超微结构改变是不同的。因此，我们应当重视高血压的防治。     

bFGF对大鼠局灶性脑缺血后神经细胞凋亡及外Bcl-2、Bax的影响

目的：探讨bFGF对缺血后神经细胞的保护作用．方法：用线栓法制作局灶性日缺血大鼠模型，于术前1h、术后第1天、第 2天连续3天侧脑室注射bFGF，分 1μg／d、2μg／d、4 μg／d 3组，观察缺血程度、梗塞体积、Bcl-2、Bax蛋白的合成。结果：bFGF能减轻脑缺血程度，减少梗塞体积（25.2％）及凋亡细胞数，提高半暗带内Bcl-2蛋白的合成，减低缺血灶内Bax蛋白的合成，各剂量组间无显著差异。结论：bFGF可作为一种有效的神经细胞保护剂．保护神经细胞免受缺血的损害。     

Attenuated neuropathology by nilvadipine after middle cerebral artery occlusion in rats

We investigated the effects of nilvadipine, a calcium antagonist, on cerebral ischemia in rats. Under halothane anesthesia, 30 rats had a 3-0 nylon suture introduced through the extracranial internal carotid artery to occlude the left middle cerebral artery. Nilvadipine was dissolved in polyethylene glycol 400. Immediately following occlusion, group 1 rats (n = 10) were treated subcutaneously with vehicle and group 2 and 3 rats were treated with 1.0 (n = 10) and 3.2 (n = 10) mg/kg nilvadipine, respectively. Perfusion fixation was performed 24 hours later, and the histopathologic outcomes were quantified. In group 1 infarct volume was 28.2 +/- 11.4% of the total cerebral volume; in groups 2 and 3 infarct volumes were 25.5 +/- 11.6% (NS) and 13.9 +/- 9.2% (p less than 0.05 different from group 1), respectively. Nilvadipine decreased ischemic neuronal injury in a dose-dependent manner and may be of use in the treatment of cerebral ischemia.     

Reduction of infarct volume by magnesium after middle cerebral artery occlusion in rats

The effects of magnesium, an endogenous inhibitor of calcium entry into neurons, upon ischemic brain damage were investigated using a well-characterized model of focal cerebral ischemia in rats. Infarct volumes were determined by 2,3,5-triphenyltetrazolium chloride transcardiac perfusion 48 h after middle cerebral artery (MCA) occlusion. The area of ischemic damage was quantified by image analysis in coronal sections taken every 0.5 mm. MgCl2 (1 mmol/kg) was injected intraperitoneally just after MCA occlusion and again 1 h later. Posttreatment with MgCl2 (16 control and 16 treated rats) significantly reduced the cortical infarct volume. Compensation for the hyperglycemic effect of MgCl2 with insulin (17 rats) further reduced the infarct volume in the neocortex. No systemic effects of either treatment could account for the observed neuroprotection.     

CBF changes associated with focal ischemic preconditioning in the spontaneously hypertensive rat.

Experimental stroke models exhibit robust protection after prior preconditioning (PC) insults. This study comprehensively examined cerebral blood flow (CBF) responses to permanent middle cerebral artery (MCA) occlusion in spontaneously hypertensive rats preconditioned by noninjurious transient focal ischemia, using [(14)C]iodoantipyrine autoradiography at varied occlusion intervals. Preconditioning was produced by 10-min occlusion of the MCA and ipsilateral common carotid artery under halothane anesthesia. These vessels were permanently coagulated 24 h later in na?ve, PC, and sham-operated rats. Infarct volumes were determined from hematoxylin-eosin-stained frozen sections after 1 or 3 days. Edema-corrected infarct volume was reduced from 127+/-21 in na?ve rats to 101+/-31 and 52+/-28 mm(3) in sham and PC groups, respectively, at 1 day, with similar results at 3 days. All animals exhibited a consistent CBF threshold for infarction (approximately 30 mL/100 g/min). Tissue volumes below this threshold were identical in na?ve and PC groups after 15-min occlusion. However, by 3 h the volume of ischemic cortex decreased in the PC group but remained unchanged in na?ve rats, predicting final infarct volumes. Cerebral blood flow recovery was confirmed in brains of individual rats evaluated by repeated laser Doppler perfusion imaging during the same 3-h interval. Modest sham protection correlated with better-maintained global perfusion, detectable also in the contralateral cortex, apparently reflecting the PC effects of prior anesthesia. These results establish that timely reperfusion of penumbra, achieved by synergistic mechanisms, is a primary determinant of PC-induced protection in experimental stroke.     

Modified permanent middle cerebral artery occlusion rat model aiming to reduce variability in infarct size

In animal cerebral infarct experiments, the most important aspect is to produce consistent infarct size and localization. In an attempt to improve the conventional middle cerebral artery (MCA) coagulation technique, we developed a new animal model using a microclip to reduce variability in infarct size. Male Sprague-Dawley rats were subjected to right MCA occlusion. The animals were divided into two groups; conventional MCA occlusion group (Group 1; n = 9) and modified clip occlusion group (Group 2; n = 9). In Group 2, the proximal portion of MCA was occluded by applying a small clip just proximal to the olfactory nerve, and the MCA from the clipped position to the position just proximal to the level of the inferior cerebral vein was electrocoagulated using a bipolar diathermy in the same manner as in Group 1. In other words, the only difference between these two groups was the manner of occlusion of the most proximal portion of the MCA. Rats were killed 24 hours after the stroke-inducing surgery, and infarct volume was determined by an image analysis program following staining with 2,3,5-triphenyltetrazolium chloride. The cortical infarct volumes were 51.0 +/- 13.8% in Group 1 and 46.3 +/- 6.2% in Group 2. The scattering of cortical infarct volume was significantly small in Group 2 (p=0.0176). The differences in scattering of striatal and total infarct volumes did not reach statistical significance. The present results demonstrated that the new MCA occlusion model using a clip significantly reduces the variability in cortical infarct volume, solving the problems of the model using coagulation alone. That permanent MCA occlusion model using a clip is an excellent method that produces more consistent and reproducible infarction.     

Focal cerebral infarction in the rat: II. Neuropathological study and local cerebral blood flow pattern

We have recently reported that middle cerebral artery (MCA) occlusion in the rat produces a uniform pattern of cerebral ischemia in an acute phase. This study was done to determine if this model is also useful for quantitative evaluation of infarction size in a chronic phase. [Methods] Sprague-Dawley rats were anesthetized with halothane and left MCA was occluded via transretro-orbital approach. The following studies were done. Neuropathological study was done one week after MCA occlusion. After perfusion fixation, the brain was cut into 6 coronal slices and stained sections were examined. Local cerebral blood flow patterns were observed by 14C-iodoantipyrine autoradiographic technique 1, 2, and 5 days after the occlusion. [Results] Neuropathological studies invariably showed infarct in the cortex and the lateral part of the basal ganlia. The ratio of the infarct to the total areas of both hemispheres in 6 coronal sections was 14.05 +/- 2.66% (Mean +/- SD) in MCA occluded animals (N = 14) and 0.59 +/- 0.46% in sham operated animals (N = 12). Relative to the contralateral hemisphere, marked reduction in CBF was seen in the territory of the MCA and moderate reductions were also seen in the surrounding areas. The same pattern of increased CBF as previously reported was also seen in the ipsilateral substantia nigra and globus pallidus 1, 2, and 5 days after the occlusion. These results indicate the usefulness of this chronic focal cerebral infarction model in the evaluation of infarction.     

The free radical spin-trap alpha-PBN attenuates periinfarct depolarizations following permanent middle cerebral artery occlusion in rats without reducing infarct volume

The effect of the free radical spin-trap alpha-phenyl-butyl-tert-nitrone (alpha-PBN) in permanent focal cerebral ischemia in rats was examined in two series of experiments. In the first, rats were subjected to permanent occlusion of the middle cerebral artery (MCAO) and treated 1 h after occlusion with a single dose of alpha-PBN (100 mg/kg) or saline. Body temperature was measured and controlled for the first 24 h to obtain identical temperature curves in the two groups. Cortical infarct volumes were determined on histological sections 7 days later. alpha-PBN did not significantly reduce infarct volume (control: 28.3+/-16.3 mm3 vs. alpha-PBN 23.7+/-7.4 mm3). In the second series of experiments, periinfarct depolarizations (PIDs) were recorded with an extracellular DC electrode at two locations in the ischemic penumbra for the initial 3 h following MCAO. alpha-PBN (100 mg/kg, single dose in conjunction with occlusion) significantly reduced the total number (median value of 3 PIDs in the control groups vs. 1 PID in alpha-PBN groups, p<0.001) and total duration of the PIDs (median value 662 s in the control groups vs. 162 s in the alpha-PBN groups, p<0.006). In spite of this, cortical infarct volumes determined 7 days later in the same rats were not smaller in alpha-PBN-treated rats. The study thus demonstrates that attenuation of PIDs does not always lead to smaller infarcts if permanent arterial occlusion is followed by long survival time and does not support the hypothesis that PIDs per se are critical determinants of infarct size in this situation.     

Postischemic (S)-emopamil therapy ameliorates focal ischemic brain injury in rats

(S)-Emopamil is a calcium channel blocker of the phenylalkylamine class, having potent serotonin S2 antagonistic properties and high blood-brain barrier penetrability. Previous studies have documented cerebroprotective effect in animal models of both focal and global ischemia. The present study was undertaken to define the postischemic "window" of therapeutic efficacy for this agent. Sprague-Dawley rats were subjected to permanent proximal middle cerebral artery occlusion, combined with an initial 30-minute period of halothane-induced hypotension (50 mm Hg). (S)-Emopamil (20 mg/kg) was administered intraperitoneally either 20-30 minutes prior to middle cerebral artery occlusion or 1 hour, 2 hours, or 3 hours following occlusion. Treated groups received a second similar dose 2.5 hours later and twice daily for 2 days thereafter. Brains were perfusion-fixed on the third day. Planimetric analysis of hemotoxylin and eosin-stained coronal brain sections documented a cortical infarct averaging 72.9 +/- 33.3 mm3 (mean +/- SD) in untreated rats. Cortical infarct volume was reduced by 48% (to 37.6 +/- 27.6 mm3) when therapy was initiated 1 hour postischemia (p less than 0.05). When treatment was deferred to 2 hours postichemia, mean cortical infarct volume was reduced by 34%, but this difference did not attain statistical significance. Infarct volume in rats with treatment initiated at 3 hours postischemia was indistinguishable from that in controls. Striatal infarct volume was similar in all groups. These results document a postischemic therapeutic window of cerebroprotection for (S)-emopamil lying between 1 and 2 hours after middle cerebral artery occlusion.     

The quantification of cerebral infarction following focal ischemia in the rat: influence of strain, arterial pressure, blood glucose concentration, and age

Focal cerebral ischemia was induced by occlusion of the middle cerebral artery in rats. The volumetric assessment of infarcted tissue, 2 days following occlusion, was calculated from the examination of eight preselected coronal sections. Five differing rat strains were examined. A small and variable infarcted volume was seen in Wistar-Kyoto rats; Sprague-Dawley rats had a relatively large, but still variable, infarcted volume. Of the normotensive rat strains, the most reproducible volume of infarcted tissue was seen in Fischer-344 rats; also the absolute value of the infarcted volume did not vary from one series to another in this strain. Chronic arterial hypertension, studied in both normal and stroke-prone spontaneously hypertensive rats, was associated with significantly larger infarction volumes. Age does not change the volume of necrosis: Fischer-344 rats were studied at 3, 9, and 20 months of age, and no significant differences were noted between these ages. Experimental diabetes was induced by the administration of streptozotocin 3 days prior to middle cerebral artery occlusion. Severe hyperglycemia (greater than 400 mg/dl) was associated with a considerably increased volume of infarction. The variability of the resultant lesion is high in the most commonly studied strains, but our results suggest that, for studies in normotensive rats, the use of the Fischer-344 strain produces a standardized and repeatable infarction that may be significantly modified by experimental interventions. Age is not a factor that affects the occlusion-induced infarction; in contrast, both chronic arterial hypertension and experimental diabetes aggravate the histological consequences of middle cerebral artery occlusion in the rat. We conclude that quantitative histological evaluation of infarct size allows a meaningful assessment of the gravity of focal cerebral ischemia.     

Mild focal cerebral ischemia in the rat. The effect of local temperature on infarct size

We aimed at investigating a new model of mild focal cerebral ischemia in rats with repeated, noninvasive magnetic resonance scanning combined with histology. Magnetic resonance imaging yielded information about infarct development enabling us to test the putative growth of the infarct over time. The effect of local temperature at the occlusion site in this model was furthermore tested. Thirty-three Wistar rats were subjected to 30 min of simultaneous common carotid artery and distal middle cerebral artery occlusion or sham treatment. Animals were magnetic resonance-scanned repeatedly between day one and day 14 after surgery, then sacrificed, and paraffin brain sections stained. All animals scanned 24 h after reperfusion showed an area of edema in the affected cortex, which later was identified as an infarct. Animals with a temperature of 33.9 +/- 1.5 degrees C at the MCA site (hypothermic) showed smaller infarcts (14.4 +/- 10 mm3) than animals with normothermic local temperature (36.7 +/- 0.2 degrees C, 57.7 +/- 26.4 mm3). Infarct size was maximal on day 3 after ischemia but decreased as edema subsided. Infarct volumes from histology and magnetic resonance imaging correlated well. The model reproducibly yielded cortical infarcts, which did not grow after edema had subsided. Local temperature had a considerable effect on final infarct size.