慢性肾血管性高血压大鼠脑细胞膜磷脂及游离脂肪酸含量变化

采用SD大鼠慢性肾血管性高血压模型，高效液相和气－液色诣定量法测定脑细胞胺磷脂、游离脂肪酸（FreeFattyAcidFFA）组分变化．结果显示：1．高血压组脑细胞膜磷脂组分中PI显著低于对照组（P＜0．O5），PS、PE、PC，组分轻微下降（P＞0．05）．2．FFA组分中C20；4，C22；6水平显著高于对照组（P＜0.01，P＜0．O5），C18：0水平显著低于对照组（P＜0．05），C16：0和C18：1轻度降低（P＞0．05）．提示继发性高血压大鼠伴有脑细胞膜磷脂、FFA代谢障碍．     

磷脂酶C抑制剂对脑缺血大鼠脑细胞膜游离脂肪酸释放的影响

观察磷脂酶Ｃ抑制剂苯甲基磺酰氟（ｐｈｅｎｙｌｍｅｔｈｙｌｓｕｌｆｏｎｙｌｆｌｕｏｒｉｄｅ，ＰＭＳＦ）对脑缺血后脑细胞膜游离脂肪酸（ｆｒｅｅｆａｔｔｙａｃｉｄ，ＦＦＡ）代谢的影响。方法采用ＳＤ大鼠局灶性脑缺血模型，气－液色谱分析技术观察了应用ＰＭＳＦ后不同缺血时间点脑细胞膜ＦＦＡ含量的变化。结果ＰＭＳＦ主要抑制缺血早期磷脂酰肌醇和缺血后期磷脂酰乙醇胺、磷脂酰胆碱的ＦＦＡ释放。结论磷脂酶Ｃ抑制剂对缺血脑组织有一定的保护作用。     

实验性脑缺血再灌注血及脑匀浆β—内啡肽活性变化

本文通过在21只家兔以闭塞双侧颈动脉及椎动脉法复制急性脑缺血模型,观察不同时相缺血及缺血再灌注各时相的β—EP活性变化,并同步监测了动物脑匀浆β—EP的含量。结果表明;脑缺血后各时相的β—EP较对照组显著升高(P<0.05);脑缺血30分钟后再灌注各时相的β—EP较单纯脑缺血组各时相升高更为显著(<0.05);缺血及缺血再灌流组动物海马及丘脑组织匀浆中的β—EP含量较对照组明显升高(P<0.05)。实验结果提示β-EP可能参了脑缺血及缺血再灌注后脑损伤的病理生理过程。     

亚低温对大鼠短暂性全脑缺血后皮质NOS亚型表达及神经元凋亡的影响

目的观察亚低温对大鼠全脑缺血再灌注后皮质3种一氧化氮合酶亚型表达、一氧化氮产生以及神经元凋亡的影响,探讨亚低温的神经保护机制。方法成年雄性SD大鼠,采用双侧颈总动脉阻断闭塞+低血压法制备短暂性全脑缺血动物模型,随机分为常温缺血组、亚低温缺血组和常温假手术对照组;常温时的脑温为36.5℃～37.5℃,肛温为35.9℃～36.9℃;亚低温时控制在32.5℃～33.5℃,相对应肛温为32.2℃～33.1℃;分别于缺血后及亚低温治疗后30min、2h、24h和72h观察短暂缺血对脑组织一氧化氮合酶亚型表达及神经元凋亡的影响,以及亚低温对缺血性脑损伤的保护作用。行神经元尼氏体亚甲蓝染色观察神经元数目及形态学的变化;免疫组化染色检测神经元型、诱导型和内皮型一氧化氮合酶的表达水平;应用硝酸还原酶法检测硝酸盐/亚硝酸盐水平的变化;采用TUNEL染色法并结合电子显微镜观察神经元凋亡的变化。结果常温缺血组大鼠额叶皮质3种一氧化氮合酶亚型表达水平及硝酸盐/亚硝酸盐含量均明显高于常温假手术对照组(P<0.05或P<0.01),出现凋亡神经元;低温缺血组大鼠3种一氧化氮合酶亚型表达水平和硝酸盐/亚硝酸盐含量明显低于常温缺血组(P<0.05或P<0.01),未检测到凋亡神经元。结论脑缺血后一氧化氮参与了神经元的凋亡过程,而亚低温治疗可以     

17-β雌二醇对大鼠脑缺血再灌注后Bcl-2表达的影响

目的 观察雌激素对大鼠局灶性脑缺血-再灌注损伤后bcl-2表达的影响,探讨雌激素在脑缺血-再灌注损伤中 的脑保护作用机制。方法 用线栓法制作脑缺血再灌注损伤模型。缺血2h分别再灌注3h、6h、12h、24h后断头取脑,应用TTC 染色和免疫组化方法,观察脑梗死体积及bcl-2蛋白的表达。结果 ①雌二醇组神经功能评分明显低于手术对照组(P<0.01)。 ②雌二醇组脑梗死体积较手术对照组显著缩小(P<0.01)。③在损伤区皮质,雌二醇组bcl-2表达较手术对照组明显上调(P< 0.01);在纹状体区,元显著性差异(P>0.05)。结论 ①雌二醇能明显减轻脑缺血再灌注损伤所造成的行为障碍,缩小梗塞体 积。②雌二醇脑保护机制可能通过上调皮质抑凋亡基因bcl-2的表达。     

急性脑缺血后NO与ET代谢的相互关系

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-氧化氮合成酶(NOS)抑制剂L-NNA和一氧化氮(NO)合成底物L-Arginine,观察缺血4h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含量明显增加(1262.9±387.6 vs789.3±188.4pg/mg·pro,P<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<0.05),且脑水肿减轻。本研究提示促进NO代谢能抑制缺血脑组织ET的产生。NO影响早期脑缺血可能与此途径有关。     

脑冷冻伤脑水肿时膜磷脂代谢障碍的实验研究

采用兔脑冷冻伤实验模型研究脑水肿时膜磷脂代谢障碍。检测脑冷冻伤后1min、30min、6h、24h冷冻灶周围脑组织膜磷脂花生四烯酸代谢产物的变化规律。发现冷冻伤后极早期病灶周围脑组织TXB_2。显著升高(P<0.01),6-Keto-PGF_(1α)亦升高(P<0.02),但T/6比值严重失调,早期猛增10倍。同时期内,冷冻灶周围脑组织水含量递增。伊文思蓝染色至30min组才蓝染,并随时相增剧。研究结果提示脑冷冻伤后早期出现冷冻灶周围脑细胞膜磷脂代谢障碍。     

大鼠缺血性脑线粒体损伤机制的研究

目的　研究缺血性脑线粒体功能损伤机制。　　方法　采用改良Zieve法测定脑PLA2 活力、HPLC测定线粒体磷脂含量、荧光分光光度计测脑线粒体膜流动性。　　结果　脑缺血 2 0min及再灌流早期PLA2 活性显著增强 ,随着再灌流时间延长PLA2 活性明显下降 ;缺血 2 0min再灌流 1h组线粒体卵磷脂、脑磷脂、心磷脂含量与膜流动性降低。　　结论　线粒体磷脂含量与膜流动性密切相关 ,PLA2 参与缺血性脑线粒体功能损伤。     

实验性脑缺血及再灌流期微量元素的研究

本文采用电感耦合氩等离子发射光谱法测定了大鼠全脑缺血、再灌流不同时间脑组织和全血微量元素铬、铜、锌、铁、锰、钼、铅、镉和硒的含量。脑组织铬含量在缺血30分钟后再灌流30分钟(I30′R30′)和再灌流60分钟(I30′R60′)较对照组升高(P<0.05);脑组织铜在I30′R60′较对照组升高(P<0.05)。全血铬含量在I30′R30′较对照组降低(P<0.01);全血铜在I30′R30′较缺血30分钟组和对照组均低(P<0.05)。其它元素脑及全血含量实验组与对照组无显著性差异。结果证明:再灌流时血铬、铜向脑内转移,铬、铜与缺血性脑血管病的急性损伤期有关。     

影响脑循环的中药药理研究

<正>一、脑缺血及脑缺血-再灌注损伤方面的中药药理研究1.单味中药对脑缺血及脑缺血-再灌注损伤方面的影响黄芩,肉苁蓉。乌苏里藜芦碱.三七皂苷,氧化苦参碱,刺五加提取物,红花总黄酮,金丝桃苷等中药对脑缺血具有一定的保护作用。黄芩苷为唇形科植物黄芩的主要活性成分之一。采用小鼠断头法、创伤法、大鼠大脑中动脉栓塞法建立脑损伤模型,通过观察断头喘息时间、测定脑含水量及脑组织缺血面积,结果表明黄芩苷360mg/kg剂量可显著延长断头小鼠的喘息时间(P<0.01);90mg/kg剂量可显著改善创伤性脑水肿(4P<0.05);200mg/kg剂量可显著降低大鼠脑缺血面积(P<0.05)。从而证实了黄芩苷对脑缺血损伤具有保护作     

缺血性脑卒中与脑组织β—EP含量及脑比重的关系及丹参的影响

在沙土鼠脑缺血模型上，用放射免疫分析法测定了脑组织中的β－内啡肽（β－Ｅｎｄｏｒｐｈｉｎ，β－ＥＰ）的含量，观察了缺血后脑组织β－ＥＰ含量的变化及丹参对缺血后β－ＥＰ含量变化和卒中症候的影响。结果显示：沙土鼠缺血８ｈ后β－ＥＰ含量显著增加，且与卒中定候呈正相关，与脑比重呈负相关。丹参可以改善卒中症候，减轻脑水肿，抑制缺血后β－ＥＰ的升高．提示缺血后中枢β－ＥＰ的增加将会加重缺血性损伤，丹参对内源性阿片肽系统具有抑制作用，这可能是其抗缺血性脑损伤的机理之一。     

TWEAK-Fn14 pathway inhibition protects the integrity of the neurovascular unit during cerebral ischemia.

Tumor necrosis factor-like weak inducer of apoptosis (TWEAK) is a member of the tumor necrosis factor superfamily. TWEAK acts via binding to a cell surface receptor named Fn14. To study the role of this cytokine in the regulation of the permeability of the neurovascular unit (NVU) during cerebral ischemia, TWEAK activity was inhibited in wild-type mice with a soluble Fn14-Fc decoy receptor administered either immediately or 1 h after middle cerebral artery occlusion (MCAO). Administration of Fn14-Fc decoy resulted in faster recovery of motor function and a 66.4%+/-10% decrease in Evans blue dye extravasation when treatment was administered immediately after MCAO and a 46.1%+/-13.1% decrease when animals were treated 1 h later (n=4, P<0.05). Genetic deficiency of Fn14 resulted in a 60%+/-12.8% decrease in the volume of the ischemic lesion (n=6, P<0.05), and a 87%+/-22% inhibition in Evans blue dye extravasation 48 h after the onset of the ischemic insult (n=6, P<0.005). Compared with control animals, treatment with Fn14-Fc decoy or genetic deficiency of Fn14 also resulted in a significant inhibition of nuclear factor-kappaB pathway activation, matrix metalloproteinase-9 activation and basement membrane laminin degradation after MCAO. These findings show that the cytokine TWEAK plays a role in the disruption of the structure of the NVU during cerebral ischemia and that TWEAK antagonism is a potential therapeutic strategy for acute cerebral ischemia.     

Cortical spreading depression causes a long-lasting decrease in cerebral blood flow and induces tolerance to permanent focal ischemia in rat brain.

Cortical spreading depression (CSD) has previously been shown to induce tolerance to a subsequent episode of transient cerebral ischemia. The objective of the present study was to determine whether CSD also induces tolerance to permanent focal ischemia and, if so, whether tolerance may be mediated by alterations in cerebral blood flow (CBF). Sprague-Dawley rats were preconditioned by applying potassium chloride to one hemisphere for 2 hours, evoking 19 +/- 5 episodes of CSD (mean +/- SD, n = 19). Three days later, the middle cerebral artery (MCA) was permanently occluded using an intraluminal suture. In a subset of animals, laser Doppler blood flow (LDF) was monitored over the parietal cortex before and during the first 2 hours of MCA occlusion. Preconditioning with CSD reduced the hemispheric volume of infarction from 248 +/- 115 mm3 (n = 18) in sham-conditioned animals to 161 +/- 81 mm3 (n = 19, P< 0.02). Similarly, CSD reduced the neocortical volume of infarction from 126 +/- 82 mm3 to 60 +/- 61 mm3 (P < 0.01). Moreover, preconditioning with CSD significantly improved LDF during MCA occlusion from 21% +/- 7% (n = 9) of preischemic baseline in sham-conditioned animals to 29% +/- 9% (n = 7, P< 0.02). Preconditioning with CSD therefore preserved relative levels of CBF during focal ischemia and reduced the extent of infarction resulting from permanent MCA occlusion. To determine whether CSD may have altered preischemic baseline CBF, [14 C]iodoantipyrine was used in additional animals to measure CBF 3 days after CSD conditioning or sham conditioning. CSD, but not sham conditioning, significantly reduced baseline CBF in the ipsilateral neocortex to values 67% to 75% of those in the contralateral cortex. Therefore, CSD causes a long-lasting decrease in baseline CBF that is most likely related to a reduction in metabolic rate. A reduction in the rate of metabolism may contribute to the induction of tolerance to ischemia after preconditioning with CSD.     

The metabolic effects of mild hypothermia on global cerebral ischemia and recirculation in the cat: comparison to normothermia and hyperthermia

The metabolic effects of graded whole body hypothermia on complete global cerebral ischemia and recirculation was investigated in the cat. Hypothermia was induced to one of three levels prior to ischemia; T = 26.8 degrees +/- 0.5 degrees C (n = 4), T = 32.1 degrees +/- 0.2 degrees C (n = 5), and T = 34.6 degrees +/- 0.3 degrees C (n = 6), and maintained constant throughout 16 min of ischemia and 1.5-2 h of recirculation. Intracellular cerebral pH and relative concentrations of high-energy phosphate metabolites were continuously monitored, using in vivo 31P nuclear magnetic resonance (NMR) spectroscopy. Except for the first 4 min of ischemia, no significant differences were detected in the response of adenylate intensities and intracellular pH to ischemia and recirculation between the hypothermic groups. The three hypothermic groups were then pooled into one group, and the data compared to previously published data from a normothermic group, T = 38.4 degrees +/- 0.6 degrees C (n = 14), and a hyperthermic group, T = 40.6 degrees +/- 0.2 degrees C (n = 9), subjected to the identical ischemic and NMR measurement protocols. The hypothermic animals exhibited a statistically significant reduction of cerebral intracellular acidosis, both during ischemia and recirculation, as well as a more rapid return of adenylate intensities during recirculation, compared to the normothermic or hyperthermic groups. The data thus suggest that mild hypothermia has an ameliorative affect on brain energy metabolism and intracellular pH under conditions of complete global cerebral ischemia and recirculation.     

脑缺血再灌注后脑组织c—fos基因表达与东菱克栓酶的影响

本实验采用线栓法制成大鼠大脑中动脉缺血再灌注模型,用地高辛精标记的c—fos探针进行原位杂交。结果示缺血再灌注组栓塞侧皮层及海马c—fos基因表达显著增多,图像分析灰阶值为118.6±5.1,对侧为159.6±3.1(P<0.001),东菱克栓酶组栓塞侧皮层及海马c—fos基因表达亦增多,灰阶为131.0±4.5,对侧为164.6±4.0(P<0.001)。克栓酶组与缺血再灌注组比较,栓塞侧东菱克栓酶组c—fos基因表达显示低于缺血再灌组(P<0.05),而两组栓塞对侧比较无显著差异。本实验表明,脑缺血再灌注后脑组织的c—fos基因表达显著增多,东菱克栓酶能抑制缺血后c—fos基因的表达,这可能是其治疗缺血性脑血管病的机理之一。     

自发性高血压大鼠脑缺血后脑区一氧化氮的变化

目的：研究自发性高血压大鼠（SHR）脑缺血后大脑皮质、海马、纹状体和小脑组织中一氧化氮（NO）的变化。采用放射免疫法和荧光分光光度法检测脑组织中一氧化氮合酶（NOS）和亚硝酸盐（NO2）的含量。结果显示SHR脑缺血10min,各脑区NOS和NO2,的含量均明显高于假手术组（P<0．01或P＜005）。说明了SHR脑缺血早期脑组织NO的生成增加．提示用特异的NO生成抑制剂类药物,可能有助于脑缺血的治疗。     

Post-ischemic administration of DY-9760e, a novel calmodulin antagonist, reduced infarct volume in the permanent focal ischemia model of spontaneously hypertensive rat

We assessed the effect of a novel calmodulin antagonist, DY-9760e (3-[2-[4-(3-chloro-2-methylphenyl)-1-piperazinyl]ethyl]-5,6-dimethoxy-1-(4-imidazolylmethyl)-1H-indazole dihydrochloride 3.5 hydrate) in a spontaneously hypertensive rat (SHR) permanent focal cerebral ischemia. In experiment I, the left middle cerebral artery was permanently occluded in 62 SHRs. DY-9760e (0.5 mg kg(-1) h(-1)) or vehicle alone were administered continuously i.v. for 6 h, beginning 0, 30, or 60 min after the arterial occlusion. The infarct volume was measured 24 h of ischemia. In experiment II, the effect of DY-9760e on CBF was assessed in 10 SHRs. Administration without a delay resulted in a mean infarct volume of 166.7 +/- 21.0 mm3 (vehicle; n = 10) and 125.1 +/- 31.8 mm3 (DY-9760e; n = 9). Administration with a 30 min delay resulted in a mean infarct volume of 173.2 +/- 32.4 mm3 (vehicle; n = 12) and 143.3 +/- 35.3 mm3 (DY-9760e; n = 11). Dy-9760e significantly reduced the infarct under these conditions (p < 0.05). The administration with a 60 min delay failed to reduce the infarct. DY-9760e had no effect on the CBF. Continuous i.v. administration of DY-9760e reduced infarct volume in a SHR permanent focal ischemia without affecting ischemic CBF.     

Biochemical evidence of crossed cerebellar diaschisis in terms of nitric oxide indicators and lipid peroxidation products in rats during focal cerebral ischemia

OBJECTIVES: Cerebral hypoperfusion in the contralateral cerebellar hemisphere after stroke is interpreted as a functional and metabolic depression, possibly caused by a loss of excitatory afferent inputs on the corticopontocerebellar pathway terminating in the cerebellar gray matter. This phenomenon is defined as crossed cerebellar diaschisis and can be diagnosed clinically by positron emission tomography, single-photon emission computed tomography, brain magnetic resonance imaging and electroencephalography in terms of regional cerebral blood flow or metabolic rate of oxygen measurements. MATERIALS AND METHODS: In the present study, nitric oxide indicators (nitrite and cyclic guanosine monophosphate) and lipid peroxidation products (malondialdehyde and conjugated dienes) were measured in rat cerebral cortices and cerebella after permanent right middle cerebral artery occlusion in order to assess the crossed cerebellar diaschisis. RESULTS: Nitrite values in ipsilateral cortex were significantly higher than those in contralateral cortex at 10 (P < 0.001) and 60 (P < 0.05) min of ischemia but no significant changes were observed in both cerebellum compared to the 0 min values. In both cerebral cortex and cerebellum cGMP levels at 10 and 60 min were significantly increased (P < 0.001). This increase was marked in ipsilateral cortex and contralateral cerebellum when compared with opposite cortex and cerebellum (P < 0.001). MDA values in ipsilateral cortex were significantly higher than those in contralateral cortex at 60 min of ischemia (P < 0.05). Contralateral cerebellar MDA values were found significantly higher than those in ipsilateral cerebellum at 0 (P<0.001) and 60 (P < 0.05) min of ischemia. In ipsilateral cortex, conjugated diene values at 0, 10, 60 min of ischemia were higher than those in contralateral cortex. On the other hand 0, 10, 60 min conjugated diene levels in contralateral cerebellum were significantly higher than those in ipsilateral cerebellum (P < 0.001). CONCLUSION: These findings support the interruption of the corticopontocerebellar tract as the mechanism of the crossed cerebellar diaschisis.     

The time course of glucose metabolism in rat cerebral ischemia with middle cerebral artery occlusion-reperfusion model and the effect of MK-801

Abstract

Following cerebral ischemiai, the extracellular concentration of excitatory amino acids increases, and the excitatory cell death may play an important role contributing to ischemic neuronal damage. Although sequential metabolic changes in permanent local cerebral ischemia have been reported\ the effect of reperfusion in local cerebral ischemia on glucose metabolism is less clear. In order to investigate the time course change of glucose metabolism in a middle cerebral artery occlusion-reperfusion model and the effect of dizocilpin (MK-801) on glucose metabolism, the 4C-Deoxyglucose method was used. Hypermetabolism occurred at 30 min after the middle cerebral artery (MCA) occlusioni, and reached a peak at 60 min after ischemia in both ischemic core and penumbra. The shift from hyper- to hypometabolism was observed after the ischemia. The reperfusion facilitated the decrease of cerebral glucose metabolism in the ischemic region following 2 h of MCA occlusion. The pretreatment of MK-801 (0.4 mg kg~ 7J inhibited both increased glucose metabolism during ischemia and decreased glucose metabolism during reperfusion. These findings support the hypothesis that excitation-induced hypermetabolism plays a major role in the ischemic insult following focal cerebral vascular occlusion. [Neurol Res 1996; 18: 505-508]