地高辛抗血清拮抗大鼠缺血再灌注引起的脑损伤

研究地高辛抗血清对缺血再灌注脑损伤的拮抗作用,采用了大鼠全脑缺血再灌注模型,比色法检测脑匀浆液中超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量、脑细胞膜Na+-K+-交换ATP酶活性、血清肌酸激酶(CK)含量;用放射免疫法检测脑匀浆液中内洋地黄素含量.结果发现,全脑缺血再灌注导致脑组织SOD活性和ATP酶活性显著下降,脑组织MDA水平、内洋地黄素水平和血清CK水平显著升高.地高辛抗血清能改善由于脑缺血再灌注所造成的SOD、ATP酶活性的下降以及MDA、CK和内洋地黄素水平的升高.结果表明,地高辛抗血清对脑缺血再灌注脑损伤具有保护作用,其作用机制与减轻脂质过氧化、促进自由基的清除以及改善脑能量代谢有关.这些作用可能是通过拮抗内洋地黄素的作用而实现的.     

托吡酯对大鼠脑缺血再灌注后血清超氧化物歧化酶活性、丙二醛含量及神经功能的影响

目的探讨托吡酯(TPM)对大鼠脑缺血再灌注后血清超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量和神经功能的影响。方法将SD大鼠随机分为缺血再灌注组、TPM组及假手术组;采用线栓法建立大鼠大脑中动脉闭塞模型,TPM组动物分别于插线和再灌注时腹腔注射TPM混悬液(8mg/ml,80mg/kg);各组术后24h时进行神经功能评分后处死动物。采用羟胺氧化法测定血清SOD活性及硫代巴比妥酸法测定血清MDA含量。结果血清SOD活性及MDA含量缺血再灌注组分别为(157.72±19.04)U/ml及(7.45±0.84)nmol/ml,TPM组分别为(171.25±15.72)U/ml及(6.10±0.98)nmol/ml,假手术组分别为(179.74±7.95)U/ml及(5.90±0.72)nmol/ml;与TPM组及假手术组相比,缺血再灌注组大鼠血清SOD活性明显降低,MDA含量明显升高(均P<0.05)。TPM组及假手术组间血清SOD活性和MDA含量差异无显著性。TPM组神经功能评分较缺血再灌注组有显著改善(P<0.05)。结论TPM能减少脑缺血再灌注大鼠脑组织中抗氧化酶的消耗,有效抑制氧自由基的产生及其毒性,具有减轻脑缺血神经功能障碍的作用。     

ACEI对沙土鼠缺血再灌注脑损伤的保护作用

研究血管紧张素转化酶抑制剂（ＡＣＥＩ）对沙土鼠缺血再灌注脑损伤的保护作用。阻断沙土鼠双侧颈总动脉血流３０ｍｉｎ，制成缺血再灌注模型。再灌注２０ｈ后，脑匀浆ＳＯＤ活力下降而ＬＰＯ和ＬＡ含量明显增高；术前或术后给予依那普利混合悬液灌胃，ＳＯＤ活力增加而ＬＰＯ和ＬＡ含量明显下降，差异显著。提示ＡＣＥＩ对缺血再灌注脑损伤具有预防和治疗作用。     

桃仁红花煎剂对大鼠缺血再灌注后脑组织的保护作用

目的研究桃仁红花煎剂对大鼠局灶性脑缺血再灌注后脑组织的影响。方法 45只雄性SD大鼠随机平均为给药组、模型组和对照组。采用线栓法阻塞大鼠右侧大脑中动脉,使其缺血2h后再灌注24h建立局灶性脑缺血再灌注模型。术前2h和术后3、12h分3次灌胃给予桃仁红花煎剂,总剂量是40g/kg。通过神经行为评分评定大鼠神经功能变化,按干湿重法测定脑含水量,用氯化三苯基四氮唑法测定脑梗死范围,分光光度法测定缺血区脑组织中Na+-K+-ATP酶和Ca2+-ATP酶的活性。结果在缺血再灌注3h和24h后,给药组神经行为评分明显高于模型组(P<0.05)。缺血再灌注24h,给药组脑含水量和脑梗死体积明显少于模型组(P<0.05);给药组缺血脑皮层中Na+-K+-ATP酶和Ca2+-ATP酶活性明显高于模型组(P<0.05)。结论桃仁红花煎剂对大鼠缺血再灌注后脑组织有保护作用,其机制可能与其增强Na+-K+-ATP酶和Ca2+-ATP酶的活性、减轻脑水肿有关。     

免疫干预对大鼠缺血再灌注脑损伤的保护作用

目的:探讨免疫抑制剂甲基强的松龙对大鼠缺血再灌注脑损伤的保护作用。方法:采用改良的大鼠局灶性脑缺血再灌注损伤线栓模型,将缺血1h再灌注大鼠分为假手术组、生理盐水组、甲基强的松龙组,观察脑梗塞体积、血清胞浆酶及微血管内聚集与粘附的多形核白细胞(PMNL)的变化。结果:甲基强的松龙能够缩小脑梗塞的体积,使血清LDH、CK、CK-BB明显降低,并减少PMNL在微血管内聚集与粘附。结论:甲基强的松龙干预后能够减轻脑缺血再灌注损伤。     

白藜芦醇对大鼠脊髓缺血再灌注损伤组织的保护作用

脊髓组织发生缺血,经处理恢复血流后损伤反而加重的现象称为脊髓缺血再灌注损伤,可能与血流恢复后脊髓组织的氧自由基过剩、细胞凋亡加重等有关［1］。本研究探讨脊髓缺血再灌注损伤的发病机制及防治途径,采用大鼠脊髓缺血再灌注损伤模型观察白藜芦醇造模前给药的效果。     

大剂量甲基强的松龙对缺血再灌注大鼠脑保护作用的研究

目的 探讨大剂量甲基强的松（MP）对缺血再灌注大鼠脑保护作用的机制。方法 采用大鼠全脑缺血再灌注模型,观察缺血前后应用大剂量MP对脑组织自由基和超氧化物歧化酶（SOD）含量的影响,同时做脑组织病理学观察。结果 MP治疗组脑组织丙二醛（MDA）水平较对照组（盐水组）明显降低（P＜0．01）,而SOD水平较对照组增高（P＜0．01）;脑组织超微结构观察发现MP可抑制再灌注中脑组织巨噬细胞浸润。结论 MP的脑保护作用与抑制作用自由基产生、减少抗氧化剂消耗以及抑制巨噬细胞浸润有关。     

硫酸镁对大鼠急性脑缺血再灌注损伤时ATP酶的影响

目的　探讨镁剂在动物实验性急性脑缺血再灌注 (cerebral ischemia-reperfusion,CIR)过程中对 ATP酶的影响。方法　选用 Wistar大鼠 ,按改良的 Pulsinelli法建立了大鼠颈总动脉 CIR损伤模型 ;CIR损伤 1 5 min后 ,断髓处死鼠 ,取额叶脑组织测定 ATP酶含量。结果　急性 CIR早期 ,脑中 Na -K -ATP酶活性降低极显著(P <0 .0 1 ) ,Mg2 -ATP酶和 Ca2 -ATP酶活性降低显著 (P <0 .0 5 ) ;预先应用 Mg SO4 能稳定 ATP酶的活性(Mg2 -ATP酶 ,P <0 .0 1 ;Ca2 -ATP酶、Na -K -ATP酶 ,P <0 .0 5 )。结论　 Mg SO4 对大鼠 CIR损伤的脑保护作用与防止脑内多种 ATP酶活性降低有关。     

缺血再灌注期间大鼠脑线粒体的变化

目的　观察局部脑缺血再灌注对大鼠脑线粒体呼吸链酶复合物活性、过氧化氢 (H2 O2 )产生量和脂质过氧化水平 (MDA含量 )的影响。方法　酶学方法 ,荧光法和比色法。结果　缺血 2 h后复合物 的活性即有明显下降 ,再灌注 30 m in至 4h均无恢复。酶重复合物 活性缺血时无明显变化 ,再灌注 30 m in开始下降 ,一直持续到再灌注 4h。酶复合物 活性在缺血与再灌注期间均无明显变化。缺血再灌注 1h时脑线粒体过氧化氢产生量明显上升 ,再灌注 2 h后又恢复到正常水平。 MDA含量则是在再灌注 2 h开始明显增高 ,4h时仍维持较高水平。结论　缺血再灌注可造成脑线粒体本身氧化损伤。     

人参总皂甙对大鼠脑缺血再灌注后MDA、SOD及细胞凋亡的影响

目的:观察人参总皂甙对大鼠脑缺血再灌注的保护作用,探讨其作用机制。方法:将40只大鼠随机分为4 组:假手术组、缺血再灌注组、治疗组1、治疗组2,采用线栓法制备大鼠脑缺血再灌注模型,72h断头取脑,Nissel染色光镜下观察海马CA1区病理形态变化,TUNEL法检测细胞凋亡,同时检测脑组织中丙二醛(MDA)、超氧化物歧化酶(SOD)的含量。结果:与缺血再灌注组相比,人参总皂甙治疗组光镜下病理损伤轻,脑组织中MDA含量降低、SOD含量升高,细胞凋亡数降低。结论:人参总皂甙对大鼠脑缺血再灌注损伤具有保护作用,其机制可能与抑制自由基损伤有关。     

一氧化碳对局灶性脑缺血脂质过氧化物及Na+-K+ ATP酶的影响

目的　研究一氧化碳对局灶性脑缺血脑组织脂质过氧化物及Na K ATP酶的影响 ,试图从亚细胞水平阐明CO对脑组织保护作用的机理。方法　将SD大鼠随机分为三组 (n =6 ) ,使用HO诱导剂、HO抑制剂腹腔注射为实验组 ,等量生理盐水作为对照组腹腔注射 ,12h后制成MCAO模型。栓塞后 2 4h检测CO浓度、脂质过氧化及Na K ATP酶活性。结果　与对照组相比 ,HO诱导剂组CO浓度明显升高 ,MDA减少 ,SOD及Na K ATP酶增高 (各为P <0 .0 1、P <0 .0 1、P <0 .0 5、P <0 .0 5 ) ,而HO抑制剂组CO浓度明显降低 ,MDA增加 ,SOD及Na K ATP酶活性降低 (各为P <0 .0 0 1、P <0 .0 5、P <0 .0 5、P <0 .0 5 )。HO诱导剂、HO抑制剂对非栓塞侧脑组织脂质过氧化物及Na K ATP酶的活性没有影响 (P >0 .0 5 )。结论　CO是一种信使分子 ,通过减少自由基、增加SOD及Na K ATP酶活性对局灶性缺血的脑组织起保护作用     

Antioxidant CR-6 protects against reperfusion injury after a transient episode of focal brain ischemia in rats

Oxidative and nitrosative stress are targets for intervention after ischemia/reperfusion. The aim of this study was to explore the effect of CR-6, a vitamin-E analogue that is antioxidant and scavenger of nitrogen-reactive species. Sprague–Dawley rats had the middle cerebral artery (MCA) occluded either for 90 mins or permanently. Cortical perfusion was continuously monitored by laser–Doppler flowmetry. CR-6 (100 mg/kg) was administered orally either at 2 and 8 h after MCA occlusion, or at 2 h only. Infarct volume, neurological deficit, and signs of reperfusion injury were evaluated. CR-6 was detected in plasma and brain by HPLC. CR-6 reduced glutathione consumption in the ischemic brain and superoxide generation in the isolated MCA. CR-6 decreased infarct volume and attenuated the neurological deficit at 1 and 7 days after ischemia/reperfusion, but not after permanent ischemia. Immediately after reperfusion, cortical blood flow values returned to their baseline (±20%) in several animals, whereas others showed hyper-perfusion (>20% of baseline). Reactive hyperemia was associated with adverse events such as increased cortical BBB leakage, edema, protein nitrotyrosination, COX-2 expression, and neutrophil accumulation; and with a poorer outcome, and CR-6 attenuated these effects. In conclusion, oral CR-6 administration after transient ischemia protects the brain from reperfusion injury.     

Neuroprotective effect of an antioxidant in ischemic brain injury

The production of reactive oxygen species (ROS) has been implicated in reperfusion injury after cerebral ischemia, and antioxidant enzymes are believed to be among the major mechanisms by which the cells counteract the deleterious effect of ROS after cerebral ischemia. ROS also mediate the mitochondrial signaling pathway that may lead to apoptosis following cerebral ischemia. The recent development and availability of transgenic and knockout mutant rodents that either overexpress or are deficient in antioxidant genes have provided powerful tools for dissecting the molecular and cellular mechanisms of signaling pathways, direct oxidative damage, or both that are involved in ischemic brain injury. This article focuses on the contribution of ROS or an antioxidant system to the molecular pathway of postischemic apoptosis following transient focal cerebral ischemia by using transgenic mice that overexpress the cytosolic antioxidant copper/zinc superoxide dismutase.     

Protective effects and time course of Huangqion early-stage free radical injury following brain trauma in rats

BACKGROUND: Huangqi (Astragalus mongholicus), a Chinese herb, has already been included in the "Chinese Pharmacopoeia" for the treatment of ischemic cerebrovascular disease. Secondary injury following brain injury is associated with free radical production, and Huangqi possesses the ability to ameliorate free radical-mediated injury. OBJECTIVE: This study was designed to observe the correlation between anti-free-radical properties of Huangqi and early histological changes of brain tissues following traumatic brain injury. DESIGN, TIME AND SETTING: This study, a randomized, controlled, animal experiment, was performed from May 2006 to June 2007 at the Experimental Center of Science and Technology, School of Basic Science, Liaoning Medical University, Jinzhou City, Liaoning Province, China. MATERIALS: Healthy, adult, Sprague Dawley rats of either gender were included. Huangqi injection was purchased from Heilongjiang Provincial Zhenbaodao Pharmaceutical Co., Ltd., China (National License Medical Number: Z23020781). Na -K -adenosine triphosphatase (ATPase), Ca2 -ATPase, and Mg2 -ATPase, as well as kits to measure superoxide dismutase (SOD) activity and malondialdehyde (MDA) content, were purchased from Nanjing Jiancheng Biological Reagent Company, China. METHODS: Seventy-two rats were randomly divided into three groups, with 24 rats in each group: (1) sham-operated group: rats were only exposed, but not injured; (2) model group: brain focal laceration rat models were established by free-falling. These groups were intraperitoneally injected with saline, once every 10 hours; (3) Huangqi group: rats were intraperitoneally injected with 4 mL/kg Huangqi (2 g/mL), once every 10 hours, following brain focal laceration by free-falling. MAIN OUTCOME MEASURES: Ultrastructural changes in brain tissue were observed under an electron microscope 24 hours after injury. The water content of brain tissue was measured using the dry-wet weight method. In addition, the activity of ATPase and SOD, as well as MDA content, was analyzed using biochemical indicators at 4, 24, and 48 hours after injury. RESULTS: All 72 rats were included in the fmal analysis. At 4, 24, and 48 hours after injury, ATPase activity was significantly reduced in the model and Huangqi groups than in the sham-operated group (P < 0.05), and this was reduction was time-dependent. At four hours after injury, no significant difference in ATPase activity was detected between the Huangqi group and the model group (P> 0.05). At 24 and 48 hours after injury, ATPase activity in the Huangqi group gradually decreased, but remained significantly greater than that in the model group (P<0.05). At four hours after injury, when compared with the sham-operated group, the MDA content in the model group significantly increased and remained at a high level, while SOD activity significantly decreased (P<0.05). In the Huangqi group, MDA content and SOD activity did not change at four hours after injury. However, MDA content significantly decreased, and SOD activity significantly increased, at 24 and 48 hours after injury, compared with the model group (P<0.05). Moreover, at 24 and 48 hours after injury, the water content of brain tissue was significantly lower in the Huangqi group than in the model group (P<0.05). Ultrastructural examination of cerebral cortical neurons revealed severe damage in the model group, compared to the sham-operated group, while only mild injury was observed in the Huangqi group. CONCLUSION: The protective effects of Huangqi against traumatic brain injury correlates with decreasing MDA content and increasing SOD activity.     

Protective effects and time course of Huangqi on early-stage free radical injury following brain trauma in rats★

BACKGROUND： Huangqi （Astragalus mongholicus）, a Chinese herb, has already been included in the ＂Chinese Pharmacopoeia＂ for the treatment of ischemic cerebrovascular disease. Secondary injury following brain injury is associated with free radical production, and Huangqi possesses the ability to ameliorate free radical-mediated injury. OBJECTIVE： This study was designed to observe the correlation between anti-free-radical properties of Huangqi and early histological changes of brain tissues following traumatic brain injury. DESIGN, TIME AND SETTING： This study, a randomized, controlled, animal experiment, was performed from May 2006 to June 2007 at the Experimental Center of Science and Technology, School of Basic Science, Liaoning Medical University, Jinzhou City, Liaoning Province, China. MATERIALS： Healthy, adult, Sprague Dawley rats of either gender were included. Huangqi injection was purchased from Heilongjiang Provincial Zhenbaodao Pharmaceutical Co., Ltd., China （National License Medical Number： Z23020781）. Na^＋-K^＋-adenosine triphosphatase （ATPase）, Ca^2＋-ATPase, and Mg^2＋-ATPase, as well as kits to measure superoxide dismutase （SOD） activity and malondialdehyde （MDA） content, were purchased from Nanjing Jiancheng Biological Reagent Company, China. METHODS： Seventy-two rats were randomly divided into three groups, with 24 rats in each group： （1） sham-operated group： rats were only exposed, but not injured; （2） model group： brain focal laceration rat models were established by free-falling. These groups were intraperitoneally injected with saline, once every 10 hours; （3） Huangqi group： rats were intraperitoneally injected with 4 mL/kg Huangqi （2 g/mL）, once every 10 hours, following brain focal laceration by free-falling. MAIN OUTCOME MEASURES： Ultrastructural changes in brain tissue were observed under an electron microscope 24 hours after injury. The water content of brain tissue was measured using the dry-wet weight method. In additio     

Atorvastatin protects against cerebral ischemia/ reperfusion injury through anti-inflammatory and antioxidant effects

In addition to its lipid-lowering effect, atorvastatin exerts anti-inflammatory and antioxidant effects as well. In this study, we hypothesized that atorvastatin could protect against cerebral isch-emia/reperfusion injury. The middle cerebral artery ischemia/reperfusion model was established, and atorvastatin, 6.5 mg/kg, was administered by gavage. We found that, after cerebral ischemia/ reperfusion injury, levels of the inflammation-related factors E-selectin and myeloperoxidase were upregulated, the oxidative stress-related marker malondialdehyde was increased, and super- oxide dismutase activity was decreased in the ischemic cerebral cortex. Atorvastatin pretreatment significantly inhibited these changes. Our findings indicate that atorvastatin protects against ce-rebral ischemia/reperfusion injury through anti-inflammatory and antioxidant effects.     

Protective effect of ginkgo proanthocyanidins against cerebral ischemia/reperfusion injury associated with its antioxidant effects

Proanthocyanidins have been shown to effectively protect ischemic neurons, but its mechanism remains poorly understood. Ginkgo proan-thocyanidins (20, 40, 80 mg/kg) were intraperitoneally administered 1, 24, 48 and 72 hours before reperfusion. Results showed that ginkgo proanthocyanidins could effectively mitigate neurological disorders, shorten infarct volume, increase superoxide dismutase activity, and de-crease malondialdehyde and nitric oxide contents. Simultaneously, the study on grape seed proanthocyanidins (40 mg/kg) conifrmed that different sources of proanthocyanidins have a similar effect. The neurological outcomes of ginkgo proanthocyanidins were similar to that of nimodipine in the treatment of cerebral ischemia/reperfusion injury. Our results suggest that ginkgo proanthocyanidins can effectively lessen cerebral ischemia/reperfusion injury and protect ischemic brain tissue and these effects are associated with antioxidant properties.     

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.