局灶性脑缺血再灌注损伤大鼠脑内肾素-血管紧张素系统的变化及厄贝沙坦干预的影响

目的 研究局灶性脑缺血再灌注大鼠脑内肾素-血管紧张素的变化,探讨厄贝沙坦干预的影响及其脑保护机??方法将健康雄性SD大鼠随机分为假手术组、缺血再灌注(IR)组、厄贝沙坦预处理组(厄贝沙坦组)[30 mg/(kg·d)连续灌胃3周].用线栓法制作右侧大脑中动脉缺血再灌注模型,进行神经功能缺损程度评分,TCC染色法测定梗死体积,逆转录-聚合酶链反应方法测定脑组织和外周血白细胞血管紧张素Ⅱ1型受体(AT1R)和2型受体(AT2R)mRNA表达,放免法测定脑组织血管紧张素Ⅱ(AngⅡ)水平及肾素活性.结果 (1)与IR组比较, 厄贝沙坦组神经功能缺损程度评分显著改善,梗死体积减少.(2)再灌注后24 h和72 h, IR组大鼠的缺血侧和对侧皮质、下丘脑、脑干及外周血白细胞AT1R mRNA表达和AT2R mRNA表达均显著性高于假手术组(均P<0.01);而厄贝沙坦组IR后各时间点上述部位AT1R mRNA表达明显低于IR组(均P<0.01),AT2R mRNA表达高于IR组(均P<0.01).(3)在IR后 24 h和72 h,IR组大鼠脑组织和外周血AngⅡ水平、外周血肾素活性均显著性增高;厄贝沙坦组大鼠脑组织、外周血AngⅡ和肾素活性与IR组比较差异无统计学意义.结论 脑缺血大鼠脑内AngⅡ、AT1R、AT2R表达增高,厄贝沙坦干预对脑缺血的神经保护作用可能与拮抗AT1R、抑制AT1R mRNA表达、上调AT2R mRNA表达有关.     

大鼠脑缺血再灌注后梗死体积的动态变化

目的观察大鼠大脑中动脉缺血再灌注后梗死灶体积的变化规律。方法线栓法制作大鼠局灶性脑缺血再灌注模型,观察脑缺血2h再灌注3h、24h、3d、7d、14d及21d后的神经功能缺损评分及2％氯化三苯基四氮唑(TTC)标记的梗死体积。结果缺血2h再灌注3h组已经出现较明显的梗死灶(梗死体积占前脑体积14．4％),再灌注24h组梗死体积最大(24．3％),显著大于再灌注3h、7d、14d、21d组(P<0．05)。再灌注3d组梗死灶仍较大 (23．8％),再灌注7d组梗死体积缩小(5．0％),再灌注14d组梗死灶进一步缩小(1．2％),再灌注21d组梗死灶基本消失(0．2％)。大鼠神经功能缺损评分与梗死体积之间呈显著相关(r=0．61,P<0．01)。结论脑缺血再灌注后梗死体积于24h达最大,21d时基本消失。脑缺血再灌注后神经功能缺损评分与梗死体积之间显著相关。     

拜阿司匹灵预处理对高血糖SD大鼠局部脑缺血再灌注损伤中ET-1的表达

目的 采用高血糖条件下SD大鼠局灶性脑缺血再灌注损伤模型,通过测量大鼠脑梗死体积及内皮素-1(Endothelin-1,ET-1)的表达情况,探讨预防性应用拜阿司匹灵对高血糖条件下SD大鼠局灶性脑缺血再灌注损伤的脑保护作用.方法 随机分为对照组与拜阿司匹灵组,2组按缺血90 min再灌注3 h、6 h、12 h再分为3个亚组.2组均建立高血糖模型及SD大鼠右侧大脑中动脉缺血再灌注模型.病理图像分析仪测量脑梗死体积,免疫组化方法测定ET-1的表达情况.结果 拜阿司匹灵组与对照组相同再灌注时间点相比较:梗死体积减小(P均<0.01);缺血区表达ET-1减少(P均<0.05).结论 预防性应用拜阿司匹灵能减轻高血糖条件下的局灶性脑缺血再灌注损伤,缩小梗死体积,使损伤脑区ET-1表达减少.     

疏血通对局灶性脑缺血大鼠神经保护和hsp70表达水平的影响

目的 探讨疏血通对脑缺血-再灌注后神经保护作用的机制,拟为临床应用提供理论依据.方法 90只健康雄性SD大鼠,随机分为假手术组、缺血-再灌注组和疏血通治疗组,建立大脑中动脉闭塞模型.采用神经功能缺损评分对人鼠神经功能缺损程度进行评价,HE染色、TUNEL染色和免疫组织化学染色检测大鼠脑组织梗死灶体积、细胞凋亡及hsp70表达水平.结果 经疏血通治疗后,大鼠神经功能缺损程度明显改善,除再灌注后6h,其余各时间点疏血通治疗组评分均优于缺血-再灌注组(P<0.05).疏血通治疗组大鼠梗死灶体积明显缩小(P<0.01).再灌注后6 h,缺血半暗带区和海马区即可见凋亡细胞,分别于再灌注后48 h和72 h达峰值水平,疏血通治疗组表达高峰时间延迟,且各时间点凋亡细胞数目均少于缺血-再灌注组(P<0.05).再灌注后6 h,缺血半暗带区和大脑皮质即可见少量hsp70表达阳性细胞,两组均于再灌注后24 h达峰值水平,但疏血通治疗组各时间点hsp表达水平均高于缺血-再灌注组(P<0.05).结论 疏血通通过上调脑组织hsp70表达水平,减轻脑缺血-再灌注损伤,从而使梗死灶体积缩小、神经功能改善.     

布美他尼可通过下调NKCC1和AQP4表达减轻缺血性脑水肿及神经损伤

目的探索电中性共同转运体(Na+-K+-2Cl-共同转运体-1,NKCC1)抑制剂布美他尼对大鼠大脑局灶脑缺血再灌注损伤所致脑水肿及神经功能的影响及机制。方法将SD大鼠按随机数字法分成假手术组、脑缺血组和布美他尼组。观察干预不同时间点患侧大脑半球脑含水量(brain water content,BWC)、梗死灶周围NKCC1和水通道蛋白4(aquaporin-4,AQP4)的表达变化;并于再灌注24 h检测神经行为学评分及梗死灶周围细胞凋亡情况。结果在脑缺血2 h,再灌注6 h、12 h和24 h时,NKCC1和AQP4表达进行性增高,患侧大脑半球BWC进行性增高;予布美他尼干预后,两者表达均显著下降(P<0.05),患侧大脑半球BWC亦下降(P<0.05)。同脑缺血组再灌注24 h相比,布美他尼组神经行为学评分改善(P<0.05),梗死灶周围细胞凋亡显著减少(P<0.05)。结论布美他尼可通过下调NKCC1和AQP4表达,减轻缺血性脑水肿,并改善神经功能。     

可重复性小鼠局灶性脑缺血/再灌注模型的探讨

目的介绍一种标准的小鼠局灶性脑缺血/再灌注模型的制作方法,并观察不同脑缺血/再灌注时间脑梗死体积和脑水肿的变化。方法用腔内线栓法制作脑缺血/再灌注动物模型,用TTC染色法进行脑大体观察,用甲酚紫染色法观察脑切片梗死灶,用脑血流激光多普勒监测脑血流的变化,用ImageJ软件计算脑梗死体积和脑水肿。结果当线栓封闭大脑中动脉时,脑血流就会急剧下降至最低水平,拔出线栓后脑血流迅速上升至缺血前水平。脑缺血后,脑片上呈现明显的梗死灶,脑梗死体积和脑水肿的大小较恒定。脑缺血90min再灌注24h组梗死体积、脑水肿体积、脑水肿百分数及神经功能缺损程度均显著大于脑缺血30min再灌注24h组(P<0.001)。脑缺血30min/再灌注72h脑水肿非常明显(72.6±4.3)mm3,再灌注7d时脑水肿开始减退,仅为(50.9±4.1)mm3,再灌注30d时脑容积出现萎缩,脑水肿呈负值(-20.1±1.8)mm3。结论该小鼠局灶性脑缺血/再灌注模型具有重复性好、容易操作的优点。脑缺血30min就可造成不可逆性脑损害,脑水肿在再灌注72h即达到高峰。     

国产降纤酶对大鼠缺血/再灌注脑损伤的保护作用

目的观察3种国产降纤酶对大鼠缺血/再灌注脑损伤的保护作用。方法采用线栓法大鼠局灶性脑缺血/再灌注模型,观察3种国产降纤酶对缺血/再灌注不同时程动物脑梗死体积、血流量、神经功能缺损评分及梗死灶内肉眼出血率的影响。结果持续缺血3h,降纤酶治疗的各组动物脑梗死体积明显小于生理盐水对照组(P<0.05);缺血3h再灌注3h和72h,降纤酶治疗的各组动物脑梗死体积与生理盐水组相比无明显变化,但缺血3h再灌注6h和24h,降纤酶治疗的各组动物脑梗死体积比生理盐水组明显减少(P<0.05)。缺血3h再灌注6h、24h和72h,降纤酶治疗组动物脑血流量比生理盐水组明显增加(P<0.05)。但治疗组动物行为学评分较生理盐水组无相应改善,梗死灶内有肉眼出血的动物较生理盐水组多,但无统计意义。结论国产降纤酶能明显减小缺血/再灌注脑损伤动物的梗死体积和增加脑血流量,改善损伤后的低灌注状态,对脑组织有一定保护作用。     

大鼠局灶性脑缺血再灌注中1-磷酸鞘氨醇受体1的表达变化

目的 观察大鼠局灶性脑缺血再灌注模型1-磷酸鞘氨醇受体1(S1P1)的变化,探索S1P1在脑缺血再灌注损伤中的作用.方法 雄性Wistar大鼠,随机分成假手术组、缺血2h再灌注3h组、6h组、12h组、24h组、24h+安慰剂组和24h+FTY720组.应用"线栓法"实现大鼠右侧大脑中动脉闭塞,2h后拔出线栓进行再灌注,并在相应时间点处死大鼠.再灌注24h+安慰剂组和再灌注24h+FTY720组大鼠于再灌注前10min经尾静脉注入安慰剂或S1P受体激动剂FTY720[1mg/(kg·体重)].利用免疫组化方法观察S1P1蛋白表达水平的变化,对再灌注24h+安慰剂组和再灌注24h+FTY720组大鼠进行神经功能评分、梗死体积测定和TUNEL阳性细胞计数.结果 与假手术组相比,缺血再灌注组大鼠梗死灶周围区皮质S1P1的蛋白表达水平明显升高(P<0.05),开始于再灌注后3h,12h达到高峰,24h开始下降.FTY720显著缩小梗死体积,改善神经功能评分,减少TUNEL阳性细胞数量.结论 S1P1在脑缺血再灌注过程中激活,减轻缺血再灌注损伤,发挥脑保护作用.     

人尿激肽原酶对局灶性脑缺血再灌注大鼠VEGF表达影响的研究

目的 探讨人尿激肽原酶对局灶性脑缺血再灌注大鼠脑组织血管内皮生长因子(VEGF)表达的影响.方法 采用随机数字表法将56只雄性SD大鼠分为假手术组(8只)、生理盐水组(24只)、人尿激肽原酶组(24只),其中生理盐水组、人尿激肽原酶组依据再灌注后不同取材时间又分为6 h,12 h,24 h,72 h,7 d五个亚组.采用线拴法制备大鼠局灶性脑缺血再灌注模型,采用神经功能评分、TTC染色、脑梗死体积测定、光镜检测等方法对不同组大鼠予以评价.采用免疫组化技术观察缺血再灌注不同时间点大鼠脑组织梗死中心区及半影区VEGF表达变化情况.结果 人尿激肽原酶组大鼠神经功能评分低于生理盐水组大鼠(P<0.05);24 h脑梗死体积测定,人尿激肽原酶组平均值为(53 261.96±7 326.75)μm3,生理盐水组平均值为(92 715.84±13 755.44)μm3,差异有统计学意义(P<0.05);人尿激肽原酶组VEGF表达在不同时间点均明显强于生理盐水组(P<0.05).结论 人尿激肽原酶能减轻脑缺血再灌注模型大鼠的神经功能损伤程度,减少脑梗死体积,促进VEGF的表达,具有脑缺血后神经保护作用.     

神经生长因子的脑保护作用与Caspase-3表达的相关性

目的 研究神经生长因子(NGF)的脑保护时间窗与半胱天冬酶-3(Caspase-3)表达的相关性.方法 采用兔局灶性脑缺血再灌注损伤模型,分别于再灌注后0h、1h、3h和6h将NGF立体定向导入梗死灶周,再灌注72h观察神经功能、梗死体积、灶周凋亡率和Caspase-3表达.结果 再灌注0h、1h和3 h灶周给予NGF,梗死体积分别较对照组下降50.1%、42.5%和35.2%,相应的灶周凋亡率及Caspase-3表达明显下降,神经功能恢复较好,用药越早越明显;再灌注6h给药,则无明显作用.相关分析显示梗死体积变化与Caspase-3表达具有明显相关性(P＜0.05).结论 NGF脑保护治疗时间窗与Caspase-3表达相关,抑制Caspase-3表达可能是NGF介导神经保护作用的机制之一.     

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     

血管内尼龙线栓塞大鼠大脑中动脉局灶性脑缺血模型的改进

目的 确立更规范统一的制作大鼠局灶性脑缺血模型方法，使脑梗死体积更加稳定。方法 对24只大鼠使用液态硅胶涂层尼龙线栓塞大脑中动脉，分别缺血l，2，6和24h后再灌注24h，监测缺血侧局部脑血流，测定脑梗死体积及脑水肿程度。结果 缺血后所有大鼠局部脑血流均降到缺血前基值的25％以下，TTC染色显示所有动物在缺血侧皮质和尾状核均有明显的梗死灶和缺血，缺血1h组梗死体积与缺血2h以上组有显性差异，缺血2h以上各组之间梗死体积无显性差异；各组脑水肿程度无显性差异。结论 应用硅胶涂层尼龙线结合局部脑血流监测，缺血2h以上同时予以血流监测，可制作梗死体积稳定的大鼠局灶性脑缺血模型。     

Proteasome inhibitor PS519 reduces infarction and attenuates leukocyte infiltration in a rat model of focal cerebral ischemia

BACKGROUND AND PURPOSE: Reperfusion brain injury after cerebral ischemia is associated with a developing inflammatory response at the site of infarction. Proteasome inhibitors block nuclear factor-kappaB activation and provide anti-inflammatory effects in several animal models of peripheral inflammation. We tested the novel proteasome inhibitor PS519 in a rat model of transient focal ischemia to establish its pharmacodynamics as a neuroprotection treatment and related effects on leukocyte infiltration. METHODS: Rats were subjected to 2 hours of focal cerebral ischemia by means of the filament method of middle cerebral artery occlusion (MCAo). After either 22 or 70 hours of reperfusion, infarct size was measured and neurological function, electroencephalographic (EEG) activity, and/or neutrophil and macrophage infiltration was quantified. PS519 was administered in a single intravenous bolus at 2 hours after MCAo. In addition, the therapeutic window for PS519 was estimated by delaying treatment for 4 or 6 hours after MCAo. RESULTS: Dose-response analysis of infarct volume at 24 hours revealed that PS519 neuroprotection approached 60%, and clinical evaluations showed significant improvements in neurological function and EEG activity. Neutrophil infiltration at 24 hours was also significantly decreased in cortical and striatal infarcted tissue of PS519-treated rats. Delaying the PS519 treatment up to 4 hours continued to result in significant neuroprotection. In the 72-hour injury model, infarction was reduced 40% by PS519, and significant improvements in neurological function and EEG recovery were again measured. Considerable reductions in both neutrophil and macrophage infiltration were evident. CONCLUSIONS: PS519 mitigates infarction and improves neurological recovery in brain-injured rats, an effect in part caused by a reduction in the leukocyte inflammatory response.     

Neuroprotective effects of 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox), an antioxidant in middle cerebral artery occlusion induced focal cerebral ischemia in rats

OBJECTIVES: In the present study, we have investigated the neuroprotective potential of 6hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox), in middle cerebral artery occlusion (MCAO) induced focal cerebral ischemia. METHODS: Sprague-Dawley rats were subjected to 2 hours of MCAO followed by 22 or 70 hours of reperfusion. After reperfusion, rats were evaluated for neurological deficits and cerebral infarction. Brain malondialdehyde (MDA) level and in situ terminal deoxynucleotidyl transferase mediated dUTP-biotin nick end labeling (TUNEL) were also estimated. RESULTS: Focal cerebral ischemia produced a significant infarct volume and neurological scores as compared with sham-operated animals. Cerebral ischemia reperfusion injury was associated with an increase in lipid peroxidation in ipsilateral and contralateral hemisphere of brain along with an increase in TUNEL positive cells in ipsilateral hemisphere of brain sections indicating oxidative stress and DNA fragmentation, respectively. Trolox (10 and 30 mg/kg, i.p.) treatment significantly decreased neurological damage which was evident from the reduction in infarct volume and neurological score. Trolox (30 mg/kg) also attenuated oxidative stress and DNA fragmentation. DISCUSSION: Oxidative stress-induced neuronal damage is implicated in the pathophysiology of cerebral ischemia. Our study suggests that Trolox is a potent neuroprotective agent in focal cerebral ischemia and its neuroprotective effects may be attributed to the reduction of lipid peroxidation and DNA fragmentation.     

Kallikrein基因转导对脑缺血再灌注后局部血流灌注恢复的作用

目的 探讨Kallikrein基因对脑缺血再灌注后梗死灶周围血管增生与局部脑血流灌注恢复的作用.方法 建立大鼠脑缺血再灌注模型,术后将90只大鼠按照随机数字表法分为3组.每组30只,分别是空白对照组、注射生理盐水、注射pAdCMV-人组织激肽释放酶(HTK)组.各组大鼠又分为治疗后12 h、24 h及72 h组,每组各10只.治疗前后行大鼠神经功能缺损评分.TTC染色方法测定脑梗死面积的变化,用免疫组化检测外源性HTK的表达以及局部血管内皮生长因子(VEGF)的表达,并通过14C-iodoantipyrine微示踪技术检测局部脑血流灌注(rCBF)情况.结果 与其他两组相比,pAdCMV-HTK组大鼠脑梗死面积在治疗后24h已有明显减小,72h后这种变化更明显,差异有统计学意义(P<0.05);在治疗后24 h,pAdCMV-HTK组大鼠神经功能缺损评分明显低于生理盐水组及空白对照组,治疗后72h差异更明显,差异有统计学意义(P<0.05).vEGF阳性细胞主要分布于脑梗死灶周边皮质与部分白质;pAdCMV-HTK组VEGF表达在治疗后12h、24h、72h均明显高于生理盐水组及空白对照组,差异有统计学意义(P<0.05).各组缺血再灌注后脑梗死灶周围白质与皮质rCBF均较对侧稍减少:pAdCMV-HTK组治疗后12h,梗死灶周围白质与皮质rCBF较空白对照组与生理盐水组有增高.但不明显,差异无统计学意义(P>0.05),而在治疗24h、72 h后rCBF则明显增高,差异有统计学意义(P<0.05).结论 在脑缺血再灌注后,Kallikrein基因转导可增加梗死灶周围脑组织的血管增生,改善rCBF,减小梗死面积,从而达到保护缺血神经细胞功能的作用.     

神经节苷脂对大鼠脑缺血再灌注损伤的脑保护作用

目的探讨神经节苷脂对大鼠脑缺血再灌注损伤的脑保护作用。方法采用线栓法制作缺血再灌注大鼠模型,分别用神经节苷脂(治疗组)和生理盐水(对照组)腹腔注射。观察两组大鼠缺血90min、缺血90min再灌注24h的脑梗死面积、神经功能缺损程度、细胞凋亡数、细胞凋亡率。结果治疗组大鼠于相同时间点脑梗死面积较对照组明显减小,仅表现轻度的神经功能缺损,且神经细胞的凋亡数较对照组显著减少(均P<0.01)。结论神经节苷脂能明显减小大鼠实验性脑缺血的脑梗死面积,减轻脑缺血再灌注后神经功能缺损程度,显著减轻缺血区神经元损害,具有显著的脑保护作用。     

莱菔硫烷对大鼠局灶性脑缺血再灌注损伤的保护作用及机制研究

目的 探讨莱菔硫烷对大鼠局灶性脑缺血再灌注损伤的保护作用及机制.方法 采用线栓法制备大鼠大脑中动脉阻断局灶性脑缺血模型,分别于MCAO后1h腹腔注射莱菔硫烷2.5mg/kg、5mg/kg、10mg/kg.于缺血2h再灌注24h时进行神经行为缺损评分,TTC染色评价脑梗死体积,测定脑组织中超氧化物歧化酶(SOD)活力和丙二醛(MDA)含量.免疫荧光组织化学染色法检测黄核蛋白NQ01和脂质过氧化酶Prx6的表达.结果 莱菔硫烷给药组与对照组相比均能改善大鼠脑缺血再灌注后神经行为缺损评分,减少脑梗死体积.其中5mg/kg组能显著改善大鼠脑缺血再灌注后神经行为缺损评分,减少脑梗死体积,增强SOD活性,降低MDA含量.免疫荧光组织化学染色法提示NQ01和Prx6的表达明显增强.结论 莱菔硫烷对大鼠局灶性脑缺血再灌注损伤有神经保护作用,其机制可能与上调内源性抗氧化蛋白NQ01和Prx6的表达有关.     

Effects of transection of cervical sympathetic trunk on cerebral infarct volume and oxygen free radical levels in rats with focal cerebral ischemia/reperfusion injury

BACKGROUND: Stellate ganglion block (SGB) plays a protective role on the brain, but the precise mechanism of action is not clear.OBJECTIVE: To simulate SGB by transection of the cervical sympathetic trunk (TCST) and to investigate the TCST effects on changes in cerebral infarct volume and oxygen free radical levels in rats with focal cerebral ischemia/reperfusion injury.DESIGN, TIME AND SETTING: A complete randomized control animal experiment was performed at the Institute of Neurological Diseases of Taihe Hospital, Yunyang Medical College from February to December 2005.MATERIALS: A total of 101 healthy Wistar rats, weighing 280-320g, of both genders, aged 17-18 weeks, were used in this study. 2,3,5-triphenyltetrazolium chloride (TTC) was purchased from Changsha Hongyuan Biological Company. Superoxide dismutase (SOD), malondialdehyde (MDA) and nitric oxide (NO) assay kits were provided by Nanjing Jiancheng Bioengineering Institute.METHODS: Rats were randomly divided into a TCST group, a model group and a sham operation group. Successful models were included in the final analysis, with at least 20 rats in each group. After TCST, rat models of focal cerebral ischemia/reperfusion injury were established in the TCST group by receiving middle cerebral artery occlusion (MCAO) by the intraluminal suture method for 2 hours, followed by 24 hours of reperfusion. Rat models of focal cerebral ischemia/reperfusion injury were made in the model group. Rats in the sham operation group underwent experimental procedures as for the model group, threading depth of 10mm, and middle cerebral artery was not ligated.MAIN OUTCOME MEASURES: Brain tissue sections of ten rats from each group were used to measure cerebral infarct volume by TTC staining. Brain tissue homogenate of another ten rats from each group was used to detect SOD activities, MDA contents and NO levels. Rat neurological function was assessed by neurobehavioral measures.RESULTS: Cerebral infarct volume was bigger in the model group than in the TCST group (P<0.05). Twenty four hours after cerebral ischemia/reperfusion, SOD activities were lower, whereas MDA contents and NO levels were higher in the TCST and model groups, compared with the sham operation group (P<0.05 or P<0.01). Compared with the model group, SOD activities were higher, whereas MDA contents and NO levels were lower in the TCST group (P<0.05).CONCLUSION: After TCST, cerebral infarct volume is reduced, SOD activities are increased, and MDA contents and NO levels are decreased compared to the model group in rats with focal cerebral ischemia/reperfusion injury. These changes may be associated with TCST.     

Puerarin protects brain tissue against cerebral ischemia/reperfusion injury by inhibiting the inflammatory response

Puerarin, a traditional Chinese medicine, exerts a powerful neuroprotective effect in cerebral ischemia/reperfusion injury, but its mechanism is unknown. Here, we established rat models of middle cerebral artery ischemia/reperfusion injury using the suture method. Puerarin(100 mg/kg) was administered intraperitoneally 30 minutes before middle cerebral artery occlusion and 8 hours after reperfusion. Twenty-four hours after reperfusion, we found that puerarin significantly improved neurological deficit, reduced infarct size and brain water content, and notably diminished the expression of Toll-like receptor-4, myeloid differentiation factor 88, nuclear factor kappa B and tumor necrosis factor-α in the ischemic region. These data indicate that puerarin exerts an anti-inflammatory protective effect on brain tissue with ischemia/reperfusion damage by downregulating the expression of multiple inflammatory factors.     

A new model of temporary focal neocortical ischemia in the rat.

BACKGROUND AND PURPOSE: We describe a new rat model of temporary focal ischemia that produces neocortical ischemia without the need for prolonged anesthesia. METHODS: Temporary focal cerebral ischemia was initiated during halothane anesthesia, maintained for varying periods without anesthesia, and reversed by clip removal requiring brief anesthesia. Tandem carotid and middle cerebral artery occlusion for 1-4 hours and permanent occlusion were used to determine the duration and extent of ischemia necessary to produce predictable volumes of neocortical infarction in Wistar and spontaneously hypertensive rats. RESULTS: In Wistar rats, occlusion of the right middle cerebral and both common carotid arteries resulted in cerebral blood flow reductions to approximately 8% of baseline. One hour of transient ischemia with 23 hours of reperfusion did not result in infarction. Three hours of ischemia followed by 21 hours of reperfusion resulted in infarction comparable to that caused by 24 hours of permanent ischemia. In spontaneously hypertensive rats, unilateral right middle cerebral and common carotid artery occlusion reduced cerebral blood flow to approximately 11% of baseline. Minimal damage was seen with 1 hour of reversible ischemia, but intervals of 2 and subsequently 3 hours followed by 22-21 hours of reperfusion produced progressively larger infarcts. Damage indistinguishable from that seen with 24 hours of permanent ischemia was seen with 3 or 4 hours of transient ischemia followed by 21 or 20 hours of reperfusion. CONCLUSIONS: For unanesthetized normothermic rats, cerebral blood flow reductions to 10-20% of baseline resulted in maximal infarction once ischemic durations exceeded 2-3 hours. To be effective, experimental therapies aimed at lessening infarct size or restoring blood flow must be initiated within this critical time interval.