甲基强的松龙对兔实验性脑血管痉挛的作用

目的探讨大剂量甲基强的松龙对蛛网膜下腔出血（SAH）后脑血管痉挛（CVS）的作用。方法将24只雄性新西兰白兔随机分成2组：SAH对照组和SAH＋大剂量甲基强的松龙（MP，18mg／kg）治疗组。通过枕大池二次注血法构建SAH模型，观察MP对脑基底动脉的影响。应用酶联免疫生化技术检测各组兔基底动脉血管平滑肌细胞膜蛋白激酶C（PKC）活性。结果经脑血管造影证实该剂量甲基强的松龙明显减轻实验性脑血管痉挛的严重程度，与对照组相比，PKC活性在大剂量甲基强的松龙治疗组没有明显提高。结论大剂量甲基强的松龙能够明显减轻脑血管痉挛程度，通过抑制血管平滑肌细胞来防治脑血管痉挛的发生发展。     

甲基强的松龙对兔实验性脑血管痉挛的作用

目的探讨大剂量甲基强的松龙对蛛网膜下腔出血(SAH)后脑血管痉挛(CVS)的作用。方法将24只雄性新西兰白兔随机分成2组:SAH对照组和SAH 大剂量甲基强的松龙(MP,18mg/kg)治疗组。通过枕大池二次注血法构建SAH模型,观察MP对脑基底动脉的影响。应用酶联免疫生化技术检测各组兔基底动脉血管平滑肌细胞膜蛋白激酶C(PKC)活性。结果经脑血管造影证实该剂量甲基强的松龙明显减轻实验性脑血管痉挛的严重程度,与对照组相比,PKC活性在大剂量甲基强的松龙治疗组没有明显提高。结论大剂量甲基强的松龙能够明显减轻脑血管痉挛程度,通过抑制血管平滑肌细胞来防治脑血管痉挛的发生发展。     

腰穿枕大池置管2次注血的迟发性脑血管痉挛动物模型

目的 :制作一种操作简便、重复性好的蛛网膜下腔出血 (SAH)脑血管痉挛 (CV)动物模型。方法 :选取家猪 12头 ,随机分成SAH组和生理盐水对照组 ;SAH组经腰穿枕大池置管 2次注血 ,制成SAH模型 ,对照组注入生理盐水 ;以脑血管造影和基底动脉组织学改变判定脑血管痉挛。结果 :SAH组双侧颈内动脉和基底动脉明显痉挛 (P <0 0 1) ,基底动脉有典型病理改变 ,对照组未见异常。结论 :腰穿枕大池置管 2次注血法 ,是一种简便、可靠的SAH诱发CV动物模型制作方法。     

缝隙连接阻断剂1-庚醇对脑血管痉挛的抑制作用

目的探讨缝隙连接在脑血管痉挛中的作用及观察其阻断剂在动物实验中的治疗作用。方法建立兔二次蛛网膜下腔出血模型,通过脑血管造影观察经动脉或池内注入缝隙连接阻断剂heptanol,对脑血管痉挛的抑制和治疗作用,并观察基底动脉的形态学变化。结果枕大池注血后血管造影显示基底动脉出现痉挛。在脑血管痉挛后,动脉给予heptanol对急、慢性脑血管痉挛有显著的治疗作用。预先枕大池注入heptanol再注血,造影显示基底动脉痉挛不明显(P>0.05),heptanol枕大池预处理后能显著抑制急、慢性期脑血管痉挛的形成。形态学检查发现,对照组第7d的基底动脉光镜见内皮细胞核染色质聚集,内弹力膜波纹状,平滑肌细胞分布稀疏等。动脉给药组和池内给药组也有类似变化,但范围局限、程度轻。结论缝隙连接阻断剂heptanol能有效抑制兔蛛网膜下腔出血后急性和慢性脑血管痉挛,体内试验表明缝隙连接在脑血管痉挛中可能发挥重要作用,应用其阻断剂heptanol具有显著的治疗作用。     

大鼠蛛网膜下腔出血后基底动脉病理结构的变化

目的观察大鼠蛛网膜下腔出血(SAH)后基底动脉病理结构的变化。方法采用枕大池二次注血的方法建立SAH大鼠模型,对照组同法注等量的生理盐水。观察两组大鼠基底动脉血管腔内周长、血管壁厚及其超微结构的改变。结果对照组大鼠基底动脉腔内周长、血管壁厚及其超微结构正常,SAH组大鼠血管腔内周长明显缩短,血管壁增厚,内皮细胞变性、内弹力膜增生变性、平滑肌细胞变性。结论大鼠SAH后脑血管痉挛的病理基础是血管内皮细胞通透性增高,内弹力膜增厚,平滑肌细胞变性。     

蛛网膜下腔出血后脑血管痉挛实验研究

目的　在兔蛛网膜下腔出血 (SAH)模型上 ,尝试建立经颅多普勒超声 (TCD)及血管造影 ,监测椎基动脉脑血管痉挛 (CVS)的新方法。方法　兔枕大池一次性注血 ,同时行逆行颈总动脉插管椎基动脉造影及开骨窗TCD监测。结果　逆行性脑血管造影能清晰显示椎基底动脉系统 ,注血前后血管直径差异明显 (P <0 .0 5 ) ,平均血流速度注血后明显增快 ,但中、重度痉挛之间基底动脉血流速度变化无明显差异。结论　一侧颈总动脉逆行插管椎基动脉造影 ,操作简便 ,结果可靠。采取开骨窗以提高TCD超声频率的方法 ,可获得兔基底动脉稳定的频谱图并易于重复。     

Trapidil对蛛网膜下腔出血后脑血管痉挛作用的实验研究

目的 探讨蛛网膜下腔出血（SAH）后脑血管痉挛的发生机制及其可能的治疗方法。方法 利用家兔枕大池内注血构建SAH模型，观察血小板衍生生长因子（PDGF）拮抗剂trapidil对脑基底动脉的影响。结果 脑基底动脉于SAH后48h明显变细；静脉或动脉内持续灌注trapidil 15min（1．5mg／min）后，数字减影脑血管造影（DSA）显示痉挛血管已明显扩张变粗，30min时达高峰。结论 PDGF可能参与脑血管痉挛发生的病理过程，PDGF拮抗剂trapidil可有效缓解实验性SAH后脑血管痉挛，有望成为脑血管痉挛的治疗药物。     

脑血管痉挛的选择动脉灌注及血管成型术治疗

目的 探讨早期超选择动脉内灌注及血管成型术（PTA）治疗脑血管痉挛（CVS）。方法对76例CVS病人，在全脑DSA造影中明确痉挛部位，其中6例近端、局限性CVS采用PTA，而远端、弥漫性CVS采用超选择脑动脉内灌注0．3％罂粟碱及溶栓药物治疗，直至血管口径接近正常。结果痉挛血管全部有改善．术后临床状态和神经功能状态均得到改善，无死亡。术后3月随访，Jennett预后良好64例（77．28％），较差（重残或植物状态）12例（18．18％），死亡3例（4．54％），死亡原因均为颅外因素。结论超选择动脉灌注及血管成型术是治疗脑血管痉挛的直接而有效的方法。     

辛伐他汀对兔蛛网膜下腔出血后迟发性脑血管痉挛中血管壁增殖的影响

目的 探讨辛伐他汀对兔蛛网膜下腔出血(SAH)后迟发性脑血管痉挛(CVS)中血管壁增殖的影响.方法 36只新西兰大白兔随机分为3组:①对照组,常规饲养并枕大池二次注入0.9%生理盐水;②SAH组,通过二次枕大池注血建立SAH模型;③辛伐他汀+SAH组,每日胃灌辛伐他汀5 ms/kg,连续7 d后建立SAH模型.各组兔模型前后行两次脑血管造影.灌注后取基底动脉组织制作病理切片,分别于光镜和透射电镜下观察其显微以及超微结构.采用免疫组化及免疫荧光方法检测基底动脉组织中增殖细胞核抗原(PCNA)及α-平滑肌肌动蛋白(α-SMA)表达量的变化,同时采用Real-Time PCR检测其血小板源性生长因子-B(PDGF-B)基因表达量的变化.采用SPSS10.0软件进行统计分析.结果 通过脑血管造影可以观察到二次注血后兔基底动脉出现明显的痉挛,管径变细;而给予辛伐他汀后,痉挛减轻.SAH组兔基底动脉壁略有增厚,电镜显示平滑肌细胞内合成旺盛;而给予辛伐他汀预处理后这些变化明显减轻.SAH组兔基底动脉管壁平滑肌细胞内α-SMA、PCNA、PDGF-B表达明显高于对照组(P＜0.05),而给予辛伐他汀后三者表达量明显降低(P＜0.05).结论 辛伐他汀可能通过抑制迟发性CVS中血管壁平滑肌细胞的增殖来缓解SAH后迟发性CVS.     

脑血管痉挛的选择动脉灌注及血管成形术治疗

目的 探讨早期超选择动脉内灌注及血管成形术(PTA)治疗脑血管痉挛(CVS).方法 对76例CVS病人,在全脑DSA造影中明确痉挛部位,其中6例近端、局限性CVS采用PTA,而远端、弥漫性CVS采用超选择脑动脉内灌注0.3%罂粟碱及溶栓药物治疗,直至血管口径接近正常.结果 痉挛血管全部有改善,术后临床状态和神经功能状态均得到改善,无死亡.术后3月随访,Jennett预后良好61例(80.26%),较差(重残或植物状态)12例(15.79%),死亡3例(3.95%),死亡原因均为颅外因素.结论 超选择动脉灌注及血管成形术是治疗脑血管痉挛的直接而有效的方法.     

Magnetic resonance angiography of experimental cerebral vasospasm

The purpose of this study was to observe spastic cerebral arteries by magnetic resonance angiography (MRA) and to establish acetazolamide reactivity of these vessels. After control studies using MRA and conventional angiography, subarachnoid haemorrhage (SAH) was induced on day 0 in 7 Japanese monkeys. MRA and conventional angiography were then repeated on day 7 to observe the development of cerebral vasospasm. Reactivity of cerebral vessels to acetazolamide was also studied in both control animals (angiography before SAH) and on day 7 after SAH. Cerebral vasospasm was detected by both conventional angiography and MRA on day 7. The arteries on the side of the clot were more spastic than those on the control side. MRA was superior to conventional angiography in demonstrating dilatation of both control arteries (before SAH induction) and vasospastic arteries (on day 7 after SAH) after administration of acetazolamide.     

Type V phosphodiesterase expression in cerebral arteries with vasospasm after subarachnoid hemorrhage in a canine model

Cyclic GMP (cGMP) mediates smooth muscle relaxation in the central nervous system. In subarachnoid hemorrhage (SAH), decreases in intrinsic nitric oxide (NO) cause cerebral vasospasms due to the regulation of cGMP formation by NO-mediated pathways. As phosphodiesterase type V (PDE V) selectively hydrolyzes cGMP, we hypothesized that PDE V may function in the initiation of vasospasm. This study sought to identify the altered PDE V expression and activity in the vasospastic artery in a canine SAH model. We also used this system to examine possible therapeutic strategies to prevent vasospasm. Using a canine model of SAH, we induced cerebral vasospasm in the basilar artery (BA). Following angiographic confirmation of vasospasm on day 7, PDE V expression was immunohistochemically identified in smooth muscle cells of the vasospastic BA but not in cells of a control artery. The isolation of PDE enzymes using a sepharose column confirmed increased PDE V activity in the vasospastic artery only through both inhibition studies, using the highly selective PDE V inhibitor, sildenafil citrate, and Western blotting. Preliminary in vivo experiment using an oral PDE V inhibitor at 0.83 mg kg(-1) demonstrated partial relaxation of the spastic BA. PDE V activity was increased from control levels within the BA seven days after SAH. PDE V expression was most prominent in smooth muscle cells following SAH. These results suggest that clinical administration of a PDE V inhibitor may be a useful therapeutic tool in the prevention of vasospasm following SAH.     

A model of cerebrovascular injury in rats

Although the pathophysiology of post-angioplasty restenosis has been extensively studied in extracranial arteries using transluminal vascular injury model in rodents, it is still not well known in the intracranial arteries, which have quite different structures from extracranial arteries. Here, we examined whether 1-min placement of modified intraluminal suture could induce an injury in the internal carotid artery (ICA) in rats and observed temporal profile of histological change after the injury. HE staining showed that the injured intracranial ICA was dilated, while the media was markedly thinned at 1 day after injury. The internal elastic lamina was not observed, and the media contained few cells. At 1 week after injury, a thin layer of neointimal hyperplasia was observed on the luminal side of the internal elastic lamina. Neointimal hyperplasia developed until at least 4 weeks after injury. Morphometric analysis demonstrated that the healing process of the injury was related to arterial remodeling. Immunohistochemical staining for alpha-smooth muscle actin and electron microscopic analysis showed that the neointima was composed of smooth muscle cells. Re-endothelialization was observed from 1 to 4 weeks after injury by immunohistochemical staining for von Willebrand's factor and electron microscopic analysis. Vascular endothelial growth factor was expressed in neointima on days 7 and 14. Interestingly, superoxide anion was not increased in injured arteries on day 3, when the infiltration of macrophages was intensive, but increased on day 7, when infiltrating macrophages almost disappeared. These findings might shed new light on pathophysiology of post-angioplasty restenosis in intracranial arteries.     

Cerebral vasospasm: comparison of contractile responses in isolated human and canine basilar arteries

Differences between human and canine basilar arteries in contractile responses to various agents were studied in vitro. Human basilar arteries were obtained at postmortem. Serotonin or prostaglandin F2 alpha contracted greatly both human and canine basilar arteries. There was no difference between the two vessels in serotonin- or prostaglandin F2 alpha-induced contractions. In contrast, great differences were found between the two arteries in response to norepinephrine or hemoglobin. Human basilar arteries contracted markedly to norepinephrine while canine basilar arteries did not contract to norepinephrine. This data suggests that sympathetics might play a more important role in the genesis of vasospasm after subarachnoid hemorrhage than has been previously thought. Hemoglobin did not elicit a contraction in human basilar arteries whereas it produced marked contractions in canine basilar arteries. This result indicates that possible participation of hemoglobin as a causative agent in vasospasm could be ruled out. In view of these differences between human and canine cerebral arteries, the canine seems unsuitable for an experimental model of cerebral vasospasm.     

Type V phosphodiesterase expression in cerebral arteries with vasospasm after subarachnoid hemorrhage in a canine model

Abstract

Cyclic GMP (cGMP) mediates smooth muscle relaxation in the central nervous system. In subarachnoid hemorrhage (SAH), decreases in intrinsic nitric oxide (NO) cause cerebral vasospasms due to the regulation of cGMP formation by NO-mediated pathways. As phosphodiesterase type V (PDE V) selectively hydrolyzes cGMP, we hypothesized that PDE V may function in the initiation of vasospasm. This study sought to identify the altered PDE V expression and activity in the vasospastic artery in a canine SAH model. We also used this system to examine possible therapeutic strategies to prevent vasospasm. Using a canine model of SAH, we induced cerebral vasospasm in the basilar artery (BA). Following angiographic confirmation of vasospasm on day 7, PDE V expression was immunohistochemically identified in smooth muscle cells of the vasospastic BA but not in cells of a control artery. The isolation of PDE enzymes using a sepharose column confirmed increased PDE V activity in the vasospastic artery only through both inhibition studies, using the highly selective PDE V inhibitor, sildenafil citrate, and Western blotting. Preliminary in vivo experiment using an oral PDE V inhibitor at 0.83 mg kg^-1 demonstrated partial relaxation of the spastic BA. PDE V activity was increased from control levels within the BA seven days after SAH. PDE V expression was most prominent in smooth muscle cells following SAH. These results suggest that clinical administration of a PDE V inhibitor may be a useful therapeutic tool in the prevention of vasospasm following SAH. [Neurol Res 2002; 24: 607-612]     

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.     

Mechanism of enlargement of major cerebral collateral arteries in rabbits

Major cerebral collateral arteries enlarge following bilateral ligation of the common and internal carotid arteries. The purpose of this investigation was to determine the relative contribution of cellular hypertrophy versus cellular hyperplasia to this vessel change in a morphometric analysis as well as the functional properties of remodeled vessels in an in vitro study. We assessed cell number and vessel dimensions by morphometric analysis of 16 perfusion-fixed rabbit basilar arteries. Results demonstrated significant increases in luminal diameter from 761 to 946 microns (p less than 0.01), medial cross-sectional area from 5.1 x 10(4) to 7.6 x 10(4) micron2 (p less than 0.005), smooth muscle cell volume from 9.19 x 10(5) to 1.44 x 10(6) micron3 (p less than 0.0005), and overall arterial length from 17.41 to 20.36 mm (p less than 0.005) in basilar arteries from the eight ligated rabbits compared with the eight sham-operated controls. Smooth muscle cell volume fraction and cell numerical density were unchanged whereas the number of cells per unit length of artery was increased significantly from 21.5 to 31.0 cells/micron (p less than 0.05). These data indicate that smooth muscle cell hyperplasia rather than hypertrophy contributes to increases in vessel mass. Functional properties of the basilar arteries from 10 ligated and 10 normal control rabbits were analyzed in vitro. Results showed increased contraction to potassium chloride (approximately 74%) (p less than 0.01) and increased sensitivity of smooth muscle to acetylcholine (p less than 0.05) while maximal relaxation was the same as control in the ligated animals.(ABSTRACT TRUNCATED AT 250 WORDS)     

Local delivery of 17beta-estradiol improves reendothelialization and decreases inflammation after coronary stenting in a porcine model

In the current study, we investigated the effect of local intravascular delivery of 17beta-estradiol (17beta-E) on subsequent in-stent neointimal hyperplasia. Twenty-seven stents were implanted in coronary arteries of juvenile swine. Coronary arteries were randomized to local treatment with 17beta-E or no drug therapy (control-vehicle treated). Twenty-eight days post-treatment, angiographic images revealed an improved minimal lumen diameter (2.2 +/- 0.2 vs. 1.3 +/- 0.2 mm, P < 0.005) and a reduction of late lumen loss (1.7 +/- 0.2 vs. 2.3 +/- 0.1 mm, P < 0.01) in 17beta-E-treated vessels compared to control-vehicle treated. Histological analyses showed a reduction of stenosis (51.49 +/- 6.75 vs. 70.86 +/- 6.24%, P < 0.05), mean neointimal thickness (0.51 +/- 0.07 vs. 0.83 +/- 0.14 mm, P < 0.05) and inflammation score (1.29 +/- 0.28 vs. 2.85 +/- 0.40, P < 0.05) in 17beta-E-treated arteries compared to control-vehicle treated arteries. Immunohistochemistry analyses revealed a reduction of proliferating smooth muscle cells and increased in-stent reendothelialization in 17beta-E-treated arteries. Finally, we observed a correlation between neointimal hyperplasia and inflammation score, which in turn, was inversely related to reendothelialization. Locally delivered, 17beta-E is inhibiting the inflammatory response and smooth muscle cells proliferation and improving vascular reendothelialization which together are contributing to reduce in-stent restenosis in a porcine coronary injury model. Together, these data demonstrate the potential clinical application of 17beta-estradiol to improve vascular healing and prevent in-stent restenosis.