局灶性脑缺血大鼠脑组织硫化氢水平的动态变化

目的：观察大鼠局灶性脑缺血过程中不同时间内源性H2S含量的变化。方法健康成年雄性Sprague-Dawley（ SD）大鼠共192只,体重250～300 g,随机分为假手术组、缺血1 h组、缺血3 h组,缺血6 h组,缺血9 h组,缺血12 h组,缺血24 h组。假手术组共48只（不同时间点各8只）,其余组各8只。其中96只观察计算梗死体积,另96只测定其他指标。采用Zea-Longa线栓法建立局灶性脑缺血模型,参照Longa评分法,对大鼠进行神经功能缺损程度的评分,于术后1、3、6、9、12和24 h后断头取脑,观察并计算脑梗死体积,检测脑组织中H2 S水平。结果与假手术组比较,缺血1 h组无明显变化,从缺血3 h到24 h,出现不同程度的神经功能缺损症状,随着时间的延长,缺血3、6、9、12和24 h时梗死灶增大（ P ＜0後．01）,各组大鼠脑组织中H2S水平均明显降低（ P ＜0．05或＜0．01）。结论缺血3h后,随缺血时间延长,脑组织梗死体积逐渐增大,H2 S含量明显降低。     

缺血再灌注时间对小鼠大脑中动脉闭塞模型的影响

目的:探讨不同缺血时间对小鼠大脑中动脉闭塞(MCAO)所致脑缺血-再灌注损伤的影响。方法:以雄性C57BL/6J小鼠为研究对象,线栓法致小鼠局灶性脑缺血,分别在缺血0.5,1和2 h后进行再灌注。再灌注24 h后,进行神经行为学评分,计算存活率、脑梗死率及脑水含量。结果:缺血后各组小鼠均出现不同程度的缺血损伤。缺血1 h再灌注24 h组小鼠出现明显的神经行为缺陷,脑梗死体积和脑水含量与假手术组相比有显著性差异,且变异系数最小,显示其最稳定。结论:缺血1 h再灌24 h可引起小鼠大脑中动脉供血区域梗死大小适宜,稳定性好,可作为研究脑缺血生理病理和药效学评价的动物模型。     

ST-1抗大鼠局灶性脑缺血再灌注损伤作用

目的:证实双萜类化合物ST-1的抗大鼠脑局灶性缺血再灌注损伤作用。方法:大鼠大脑中动脉内栓线阻断法制作脑缺血再灌注模型,以行为学、脑梗死体积、脑匀浆丙二醛(MDA)含量和超氧化物歧化酶(SOD)的活力和海马CA1区神经元的病理学等指标评价ST-1的抗脑局部缺血复灌损伤作用。结果:大鼠静脉注射ST-1 5~20 mg.kg-1,剂量依赖性地降低脑局灶性缺血再灌注引起的梗死体积,降低脑MDA的含量,增加SOD活力,减轻海马CA1区神经元损伤;高剂量组行为学损伤明显减轻。结论:ST-1有抗大鼠脑局灶性缺血再灌注损伤作用。     

芪参胶囊对大鼠局灶性脑缺血再灌注损伤的保护作用

目的研究芪参胶囊对大鼠局灶性脑缺血再灌注损伤的保护作用。方法用线栓法建立大鼠局灶性脑缺血模型,大鼠于缺血1h再灌注2h断头取脑,检测大脑组织Ca2 -ATPase,Na ,K -ATPase,NOS活性和NO,水的含量及大脑皮层神经元内游离钙离子浓度,行为学评价及梗死面积,常规石蜡切片,HE染色,作病理学检查。结果芪参胶囊显著降低缺血再灌注后大脑皮层神经元内游离钙离子浓度及大脑组织NOS活性,NO的含量和水肿程度及梗死面积;显著增强Ca2 -ATPase,Na ,K -ATPase的活性;病理学检查显示芪参胶囊能明显减轻脑水肿及神经元坏死程度。结论芪参胶囊对大鼠局灶性脑缺血再灌注损伤有明显保护作用。     

缓激肽预处理对大鼠局灶性脑缺血的影响

目的研究缓激肽预处理对大鼠局灶性脑缺血/再灌注损伤的影响。方法线栓法制备大鼠大脑中动脉缺血/再灌注模型,在缺血前由颈外动脉泵入缓激肽,对照组给予等量生理盐水,缺血2 h再灌注24 h后,观察脑梗死体积、脑含水量、血脑屏障通透性及组织病理学的变化。结果缺血前15 m in给予缓激肽组与对照组相比,梗死体积减小、水肿程度减轻、血脑屏障通透性降低、相关脑区神经元损伤程度减轻。结论预先给予缓激肽可对脑缺血损伤起保护作用,这可能是通过保护脑血管、减少梗死体积来起作用的。     

天麻素对大鼠脑缺血再灌注损伤的保护作用

目的 探讨天麻素对大鼠脑缺血再灌注损伤的保护作用及其机制.方法 线栓法建立大鼠局灶性脑缺血再灌注损伤模型,缺血2 h、再灌注24 h后检测大鼠的神经功能并评分,取大脑用红四氮唑染色后测定脑梗死灶面积和脑含水量,生化法测定大鼠脑组织匀浆中丙二醛(MDA)的含量,超氧化物歧化酶(SOD)和Na+-K+-ATP酶的活性.结果 天麻素能改善中动脉闭塞所致局灶性脑缺血大鼠的神经功能,明显缩小梗死面积,降低脑含水量,提高脑组织内Na+-K+-ATP酶和SOD的活性,降低MDA含量.结论 天麻素对大鼠脑缺血再灌注损伤有显著的保护作用;其机制可能与抗氧化、清除过多自由基和改善能量代谢有关.     

黄芪注射液对大鼠局灶性脑缺血再灌注后梗死体积的影响

目的：本研究主要探讨黄芪注射液对大鼠局灶性脑缺血再灌注后的梗死体积的影响。方法：采用线栓法制作大鼠局灶性脑缺血再灌注损伤模型,腹腔注射黄芪注射液,TTC染色计算脑梗死体积比。结果：缺血2h,3h用药后梗死体积比缺血再灌注组差异有统计学意义（P〈0.05）,缺血4h,5h用药后梗死体积比缺血再灌注组差异没统计学意义（P〉0.05）。结论：黄芪注射液可以减少时间窗以内的脑梗死体积,超过时间窗对脑梗死体积没有差异性。     

三乙酰莽草酸对大鼠局灶性脑缺血再灌注过程中血浆血管活性物质量和脑髓过氧化物酶活性的抑制作用(英文)

目的探索血浆内血管活性物质和白细胞浸润在大鼠局灶性脑缺血再灌损伤中是否影响力不同及三乙酰莽草酸(TSA)的保护作用。方法线栓法制备大鼠大脑中动脉缺血90 min再灌注3 ~48 h模型。分别于缺血开始和缺血60 min时给予TSA 50~200 mg·kg-1ig。分别用荧光分光光度法和放射免疫法测定血浆5-羟色胺(5-HT)和血栓烷素B2(TXB2)含量,化学法测定脑皮层中髓过氧化物酶(MPO)活性。结果大鼠脑缺血再灌注3 ~24 h时血浆5-HT和TXB2含量及脑MPO活性呈时间依赖性升高,48 h后5-HT, TXB2含量降至假手术组水平,而MPO活性仍明显高于未缺血侧脑皮层。TSA(100和200 mg·kg-1)可显著抑制缺血90 min再灌注24 h时血浆5-HT和TXB2含量及脑MPO活性增高。结论大鼠局灶性脑缺血再灌注过程中血浆中血管活性物质量和脑组织中MPO活性表现出不同的时相变化,并且对脑损伤影响力不同,TSA可有效保护缺血脑组织。     

乌司他丁对大鼠脑梗死灶周围脑组织ICAM-1表达的影响

目的探讨乌司他丁对大鼠脑缺血梗死灶周围组织ICAM-1表达的作用。方法 54只SD大鼠随机分为假手术组、模型对照组和乌司他丁干预组各18只。采用改良Zea-Longa线栓法制作大脑中动脉栓塞模型。乌司他丁干预组于造模成功后0.5h经尾静脉注入乌司他丁注射液1万U,术后6、12、24h断头取脑,采用免疫组织化学法测定梗死灶周围脑组织ICAM-1表达水平。结果脑缺血损伤后,缺血坏死周边区ICAM-1的表达逐渐增多,并于24h达高峰;乌司他丁干预组术后6、12、24h脑组织中ICAM-1表达较模型对照组明显降低(P<0.01)。结论脑缺血损伤可诱导缺血周边组织ICAM-l表达,乌司他丁可通过降低脑梗死大鼠ICAM-1表达,从而减轻炎症反应,保护脑组织。     

天麻素对大鼠局灶性脑缺血损伤的保护作用研究

目的 探讨天麻素(Gastrodine,Gas)对大鼠局灶性脑缺血损伤的保护作用及机制.方法 线栓法制备大鼠大脑中动脉栓塞模型,缺血2h后再灌注.天麻素(5,10,20 mg/kg)再灌注同时腹腔给药,再灌注后24 h,测定大鼠神经功能缺失评分和脑梗死体积,伊文思蓝法观察血脑屏障破坏程度,Western blot检测梗死半暗带皮层组织炎症因子TNF-α、IL-1β和IL-6的蛋白表达.结果 天麻素(10,20 mg/kg)能改善大鼠脑缺血后神经功能缺失,减小脑梗死体积,降低血脑屏障的通透性.天麻素(20 mg/kg)对梗死半暗带皮层组织TNF-α表达的抑制率为24％,对IL-1β表达的抑制率为34％,对IL-6表达水平的抑制率为38％.结论 天麻素可降低血脑屏障的通透性,其通过减低炎症反应而对局灶性脑缺血损伤发挥保护作用.     

氧化苦参碱对大鼠局灶性脑缺血损伤的保护作用及其抑制凋亡的作用机制

目的探讨氧化苦参碱(oxymatrine,OMT)对大鼠局灶性脑缺血损伤的保护作用及其抑制凋亡的作用机制。方法采用大鼠永久性大脑中动脉阻塞(permanent middle cer-ebral artery occlusion,pMCAO)方法,建立脑缺血模型,大鼠pMCAO术后通过腹腔给予OMT(30、60、120 mg.kg-1),以脑梗死体积、脑含水量和行为学症状等指标评价OMT对脑缺血的神经保护作用。通过HE染色方法观察OMT对缺血皮层神经细胞的形态变化以及数目的影响;应用Westernblot法检测OMT对缺血皮层Caspase-3、Bcl-2、Bax蛋白水平的表达。结果在大鼠局灶性脑缺血体内模型中,OMT(30、60、120 mg.kg-1)可明显减小脑梗死体积、脑含水量和改善行为学体征(P<0.01)。HE染色结果提示:OMT可明显增加神经细胞的存活率改善神经细胞的形态。Western blot结果显示:与假手术组相比,大鼠pMCAO后3、6、12、24 h,缺血皮层Caspase-3、Bax蛋白的表达水平在3 h开始上升,24 h达到峰值;而Bcl-2的表达水平在3h开始下降,24 h降到最低。给予OMT后可下调pMCAO大鼠缺血皮层中Caspase-3、Bax蛋白,上调Bcl-2蛋白。结论氧化苦参碱对脑缺血损伤有直接的神经保护作用,其机制可能通过上调Bcl-2及下调Bax、Caspase-3蛋白水平抑制凋亡发生。     

Hydroxysafflor yellow a protects neuron against hypoxia injury and suppresses inflammatory responses following focal ischemia reperfusion in rats

Previous data demonstrated that hydroxysafflor yellow A (HSYA), a yellow color pigments extracted from the safflower, was an effective agent against focal cerebral ischemia. In the present study we demonstrated that HSYA prevented the injury in cultured cerebral cortical neurons induced by oxygen-glucose deprivation and increased the cell viability, as shown by the inhibition of both LDH and NO efflux. Further, HSYA administered orally 3 d before middle cerebral artery occlusion has the capacity to reduce cerebral infarct size and edema after 2 h cerebral ischemia followed by 24 h reperfusion in rats, and to significantly improve neurological behavior scores. Mean while, treatment with HSYA significantly decreased both mRNA and protein levels of IL-1beta, TNF-alpha in ischemic brain tissue. These results suggested that the protection of HSYA results from, at least in part, suppression of inflammatory responses following focal ischemia reperfusion.     

葛根黄豆苷元对沙土鼠脑缺血及再灌注损伤的神经保护作用(英文)

目的研究葛根黄豆苷元（DZ）对沙土鼠脑缺血及缺血再灌注损伤的保护作用。方法采用结扎沙土鼠左侧及两侧颈总动脉分别制备脑缺血及缺血再灌注损伤模型,术前20 min腹腔注射DZ(35、70 mg·kg^-1),双盲法记录沙土鼠脑缺血1、3、6h后卒中指数;组织学方法检查神经元的病理学损伤;脑缺血24 h及缺血10 min再灌24 h后,利用干燥称重法及原子吸收分光光度法测定脑内水、钙、钠离子的含量。结果与溶媒组相比,DZ能明显降低沙土鼠卒中指数,缓解缺血性脑神经元的损伤（P<0.05）。缺血24 h后,DZ治疗组沙土鼠脑组织内水、钙、钠含量明显低于溶媒组（P<0.05）。缺血10min再灌24 h后,与溶媒组相比,DZ也明显降低缺血再灌注沙土鼠脑组织中水、钙、钠的含量（P<0.05和P<0.01）。结论 DZ能改善沙土鼠脑缺血及缺血再灌注性脑损伤,其机制可能是减少钙、钠、水在脑细胞内的蓄积。     

低分子肝素对脑缺血再灌注大鼠NF-κB、MPO活性的影响

目的探讨低分子肝素（Low molecular weight heparin，LMWH）对核转录因子-κB p65（NF-κB p65）和髓过氧化物酶（MPO）活性的影响。方法将Wistar大鼠135只，随机分为假手术组、缺血再灌注组（IR组）、LMWH治疗组，线栓法建立局灶性脑缺血再灌注模型。IR组于再灌注前5min尾静脉注射LMWH，1．5mg／kg。采用免疫组化法和生化法观察各组缺血90min再灌注3、6、12、24、48h点NF-κB p65表达、MPO活性变化，并进行脑含水量检测、TIC染色和HE染色观察脑梗死体积及病理形态学变化。结果①假手术组及IR组的未缺血侧大脑半球可见少量NF—κBp65表达于胞质，再灌注后NF-κB p65表达发生核移位，于胞核表达增加，再灌注12h达高峰；与IR组比较，LMWH治疗组能减少NF-κB p65的核移位（P〈0．05）；②再灌注12h后，MPO活性升高，于24h达到高峰；与IR组比较，LMWH治疗组能减少MPO活性（P〈0．05）；③与IR组比较，LMWH治疗组脑含水量较IR组减少，脑梗死体积较IR组缩小，差异有统计学意义（P〈0．05）；④LMWH治疗组脑组织缺血损伤病理学改变明显轻于IR组；⑤假手术组、IR组和LMWH治疗组凝血酶原时间（胛）和白陶土部分凝血活酶时间（KPTT）检测比较，差异无统计学意义（P〉0．05）。结论脑缺血再灌注损伤出现NF-xB活化和中性粒细胞浸润的炎性反应级联反应。LMWH对脑缺血再灌注损伤有保护作用，可能与减少NF-κB p65活化和减轻中性粒细胞浸润有关，且对凝血指标胛和KPTT无明显影响。     

Caffeic acid ameliorates early and delayed brain injuries after focal cerebral ischemia in rats

AIM:To investigate the effects of caffeic acid on early and delayed injuries after focal cerebral ischemia in rats, and the possible relation to 5-lipoxygenase inhibition. METHODS: Transient focal cerebral ischemia was induced by middle cerebral artery occlusion in Sprague-Dawley rats. Caffeic acid (10 and 50 mg/kg) was ip injected for 5 d after ischemia. The brain injuries were observed, and the levels of cysteinyl leukotrienes and leukotriene B4 in the brain tissue were measured. RESULTS: Caffeic acid (50 mg/kg) ameliorated neurological dysfunction and neuron loss, and decreased infarct volume 24 h after ischemia; it attenuated brain atrophy, infarct volume, and particularly astrocyte proliferation 14 d after ischemia. In addition, it reduced the production of leukotrienes (5-lipoxygenase metabolites) in the ischemic hemispheres 3 h and 7 d after ischemia. CONCLUSION: Caffeic acid has protective effect on both early and delayed injuries after focal cerebral ischemia in rats; and this effect may partly relate to 5-lipoxygenase inhibition.     

Wogonin inhibits ischemic brain injury in a rat model of permanent middle cerebral artery occlusion

The present study evaluated the effect of wogonin, a flavonoid originated from the root of Scutellaria baicalensis GEORGI, on focal ischemic brain injury in rats. Focal brain ischemia was induced by the permanent occlusion of middle cerebral artery (pMCAO) for 24 h with a silicone rubber cylinder inserted through the right internal carotid artery. We found that wogonin, intraperitoneally administered at a dosage of 20 mg/kg at 30 min before and 4 h after the surgery, reduced the pMCAO-induced infarct areas in the cerebral cortex as well as in the striatum. The total volume of infarction was significantly reduced by the treatment with wogonin. In addition, wogonin was found to significantly improve the pMCAO-induced behavioral deficits at 24 h after the surgery. Taken together, these results demonstrate that wogonin inhibits ischemic brain injury and improves behavioral dysfunction caused by pMCAO. These findings, along with previous reports demonstrating the neuroprotective effects of wogonin, provide strong pharmacological basis for the use of wogonin or Scutellaria baicalensis in the treatment of stroke.     

Involvement of cortical damage in the ischemia/reperfusion-induced memory impairment of wistar rats

The effect of ischemia/reperfusion-induced neuronal damage on the memory impairment were investigated using active avoidance and Morris water maze tasks in Wistar rats. Focal ischemia was induced by 1 h occlusion of the right middle cerebral artery (MCA) of Wistar male rats. Reperfusion was induced by releasing the occlusion and restoring the blood circulation for 24 h. The acquisition and preservation memory tested by active avoidance showed a significant difference between the sham and ischemia/reperfusion group. The water maze acquisition performance was also significant difference between sham and ischemia/reperfusion groups in both latency and moving distance. The infarction volume was increased by the ischemia/reperfusion. Furthermore, the cresyl violet staining of the ischemia/reperfusion brain showed severe neuronal damage (pyramidal cell loss) in the cortex in addition to the striatum lesion of brain. This study shows that pyramidal cell damage in the cortex lesion may be partially related to memorial disturbance in the ischemia/reperfusion brain injury.     

Kinetic Changes of COX-2 Expression during Reperfusion Period after Ischemic Preconditioning Play a Role in Protection Against Ischemic Damage in Rat Brain

A brief ischemic insult induces significant protection against subsequent massive ischemic events. The molecular mechanisms known as preconditioning (PC)-induced ischemic tolerance are not completely understood. We investigated whether kinetic changes of cyclooxygenase (COX)-2 during reperfusion time-periods after PC were related to ischemic tolerance. Rats were given PC by occlusion of middle cerebral artery (MCAO) for 10 min and sacrificed after the indicated time-periods of reperfusion (1, 2, 4, 8, 12, 18 or 24 h). In PC-treated rats, focal ischemia was induced by occlusion of MCA for 24 h and brain infarct volume was then studied to determine whether different reperfusion time influenced the damage. We report that the most significant protection against focal ischemia was obtained in rats with 8 h reperfusion after PC. Administration of indomethacin (10 mg/kg, oral) or rofecoxib (5 mg/kg, oral) 48 h prior to PC counteracted the effect of PC. Immunohistochemical analysis showed that COX-2 and HO-1 protein were induced in PC-treated rat brain, which was significantly inhibited by rofecoxib. Taken together, we concluded that the kinetic changes of COX-2 expression during the reperfusion period after PC might be partly responsible for ischemic tolerance.     

A novel Na+ and Ca2+ channel blocker, T-477, prevents brain edema following microsphere-induced permanent occlusion of cerebral arterioles in rats

One of the most common acute complications of stroke is brain edema. Treatment of edema is recommended when the condition of the patients is deteriorating. The present study was undertaken to evaluate the effect of T-477 [(R)-(+)-2-(4-chlorophenyl)-2,3-dihydro-4-diethyl aminoacetyl-4H-1,4-benzorthiazine hydrochloride], a novel neuronal Na+ and Ca2+ channel blocker, on brain edema in rats. Cerebral ischemia was induced by intra-arterial infusion of 1000 microspheres into the forebrain of freely moving rats, resulting in brain edema. T-477 was intravenously infused continuously for 24 h or twice for 3 h with a 3-h interval between infusions immediately after microsphere injection. T-477 dose-dependently inhibited the increase in brain water content by both infusion procedures; the inhibition was statistically significant at doses of 25 mg/kg per 24 h and 14 mg/kg per 9 h. Additionally, infusion of T-477 at a dose of 14 mg/kg per 9 h significantly inhibited the decrease in K content and the increase in Ca content of the forebrain. In conclusion, T-477 prevents brain edema following microsphere-induced cerebral embolism in rats.