米诺环素对大鼠脑缺血再灌注损伤的脑保护作用

目的探讨米诺环素对局灶性脑缺血再灌注损伤后的脑保护作用。方法 48只SD大鼠随机分为假手术组、生理盐水组、米诺环素治疗组和米诺环素预处理组。采用线栓法制作大脑中动脉缺血再灌注模型。用免疫组织化学法、放射免疫法、Hoechst染色和核磁共振T2WI扫描等方法,观察米诺环素对缺血再灌注大鼠脑组织COX-2、PGE2的表达、细胞凋亡及脑缺血体积的影响。结果米诺环素能降低缺血再灌注大鼠神经细胞凋亡率,减少COX-2、PGE2的表达,缩小脑梗死体积。结论米诺环素对大鼠局灶脑缺血再灌注损伤有脑保护作用。     

米诺环素对大鼠局灶性脑缺血再灌注后ICAM-1表达的影响

目的观察米诺环素对大鼠短暂性脑缺血再灌注后细胞间黏附分子1表达的影响。方法采用改良线栓法制备大鼠大脑中动脉缺血2h再灌注24h模型,随机分为假手术组、缺血再灌注模型组、米诺环素处理组和米诺环素预处理组,每组16只。模型成功后观测各组大鼠的神经行为变化、脑梗死体积以及HE染色计数缺血区中性粒细胞的浸润数目,应用免疫组化方法检测细胞间黏附分子-1的表达情况。结果米诺环素能明显改善大鼠局灶性脑缺血再灌注引起的神经行为障碍,减少脑梗死体积,减少脑缺血引起细胞间黏附分子1的表达,抑制中性粒细胞的浸润。结论米诺环素对大鼠局灶脑缺血再灌足损伤有保护作用,抑制黏附分子可能是一种机制。     

丁苯肽软胶囊对大鼠急性脑缺血再灌注损伤脑组织含水及含钙量的影响

目的 研究丁苯肽软胶囊对大鼠急性脑缺血再灌注损伤脑组织含水量及含钙量的影响.方法 选取健康SD大鼠60只,按照随机数字表随机分为6组,采用4血管法造脑缺血再灌注损伤模型,给药组分别给予不同剂量的丁苯肽软胶囊和复方丹参注射液,观察丁苯肽软胶囊对大鼠急性脑缺血再灌注损伤脑组织含水量及含钙量的影响.结果 丁苯肽软胶囊高剂量组可降低大鼠急性脑缺血再灌注损伤脑组织含水量（75.60%）及含钙量（114.53 pg/g）;中剂量组降低大鼠急性脑缺血再灌注损伤脑组织含水量（80.03%）,降低大鼠急性脑缺血再灌注损伤脑组织含钙量（132.33 pg/g）;低剂量组对大鼠急性脑缺血再灌注损伤脑组织含水量（73.93）及含钙量（106.35 pg/g）有降低趋势,但差异无统计学意义（P＞0.05）.结论 丁苯肽软胶囊能降低大鼠急性脑缺血再灌注损伤脑组织含水量及含钙量,具有脑保护作用.     

雌二醇对大鼠脑缺血再灌注损伤的保护作用

目的探讨雌二醇对大鼠局灶性脑缺血再灌注损伤的改善作用及其脑保护机制。方法线栓法建立大鼠局灶性脑缺血再灌注损伤模型,通过HE染色在光镜下观察神经细胞损伤变化,TTC染色测脑梗死体积,免疫组化法检测bcl-2阳性表达。结果与脑缺血再灌注组相比,雌二醇用药组大鼠脑标本光镜下细胞损伤变性程度轻,脑梗死体积显著缩小(P<0.01),bcl-2阳性细胞数明显上升(P<0.01)。结论雌二醇对大鼠局灶性脑缺血再灌注损伤有保护作用,雌二醇可通过促进bcl-2的上调发挥脑保护作用。     

雌二醇对大鼠脑缺血再灌注损伤的保护作用

目的探讨雌二醇对大鼠局灶性脑缺血再灌注损伤的改善作用及其脑保护机制。方法线栓法建立大鼠局灶性脑缺血再灌注损伤模型，通过HE染色在光镜下观察神经细胞损伤变化，TTC染色测脑梗死体积．免疫组化法检测bel-2阳性表达。结果与脑缺血再灌注组相比，雌二醇用药组大鼠脑标本光镜下细胞损伤变性程度轻．脑梗死体积显著缩小（P〈0．01），bel-2阳性细胞数明显上升（P〈0．01）。结论雌二醇对大鼠局灶性脑缺血再灌注损伤有保护作用，雌二醇可通过促进bcl-2的上调发挥脑保护作用。     

急性脑缺血再灌注损伤钙离子与氧自由基作用实验研究

为探讨钙离子与氧自由基在急性脑缺血再灌注损伤中的作用，用复制大鼠急性脑缺血再灌注动物模观察脑缺血再灌注过程中脑组织H2O2、Ca^2 、MDA含量及病理学变化及尼莫地平对上述指标的影响，结果表明，急性脑缺血再灌注后有细胞内钙超载和自由基代谢紊乱，且在再灌注损伤中有协同作用，加重组织损伤，促进脑水肿，尼莫地平对其有保护作用。     

γ-羟基丁酸对局部脑缺血再灌注损伤的保护作用

γ-氨基丁酸(GABA)类药物可治疗脑缺血后谷氨酸(EAA)大量释放引起的神经元损伤.我们观察γ-羟基丁酸(GHBA)对大鼠局部脑缺血再灌注后脑组织EAA含量的影响及其与脑梗死体积和脑水肿的关系,研究GHBA对脑缺血再灌注损伤的保护作用.     

米诺环素对脑缺血再灌注后明胶酶活性及血脑屏障影响的研究

目的 探讨米诺环素对大鼠局部脑缺血再灌后血脑屏障损伤的影响及其作用机制.方法 28只Wistar大鼠分为假手术组、缺血再灌注组、米诺环素组和生理盐水组.运用磁共振成像监测缺血再灌后血脑屏障损伤及梗死体积的变化,再灌注24h后进行神经功能缺陷评分和脑组织明胶酶活性测定.结果 缺血再灌后3.5h及24h,米诺环素组DWI、T2WI上异常高信号体积,T1WI增强扫描的信号强化范围、信号强度均明显低于缺血再灌注组和生理盐水组（P＜0.05）;与后两组相比,米诺环素组神经功能缺陷评分及脑组织明胶酶活性亦显著降低（P＜0.05）.结论 米诺环素能显著减轻缺血再灌注早期血脑屏障损伤,缩小梗死体积,促进神经功能恢复,其保护机制可能与米诺环素抑制脑组织明胶酶活性有关.     

环孢素A对大鼠脑缺血再灌注后IL-1β表达的影响

目的探讨环孢素A对大鼠脑缺血再灌注损伤后的脑保护作用及其对IL-1β表达的影响.方法将72只大鼠分为假手术组、生理盐水对照组和环孢素A治疗组,参照Zealonga线栓法制备局灶性脑缺血再灌注模型,大鼠脑缺血2 h再灌注22 h和70 h后,分别对各组各时间点大鼠进行脑TTC染色评价脑梗死体积、采用RT-PCR和放免法分别对缺血区皮层IL-1β基因表达和蛋白表达进行测定.结果各时间点环孢素A治疗组与生理盐水对照组相比,环孢素A治疗组脑梗死灶体积比对照组明显减小(P＜0.05);环孢素A可有效降低大鼠局灶性脑缺血再灌后脑组织中IL-1β基因和蛋白的表达(P＜0.01);与上述两组相比,假手术组各项观察指标则无明显异常.结论IL-1β参与脑缺血再灌注损伤,环孢素A对大鼠脑缺血再灌注损伤有明显的保护作用,环孢素A的脑保护机制可能与抑制缺血区内IL-1β的表达有关.     

Exendin-4对MCAO再灌注导致的脑缺血/再灌注损伤具有神经保护作用

目的 探讨GLP-1受体激动剂Exendin-4腹腔给药对大脑中动脉闭塞(MCAO)再灌注所致大鼠脑缺血/再灌注损伤的神经保护作用。方法 SD大鼠术前1 h腹腔注射Exendin-4,MCAO再灌注24 h后进行神经功能缺损评分,TTC染色计算脑梗死体积,免疫荧光观察神经元和小胶质细胞生存数量及检测凋亡通路相关蛋白的相对表达水平。结果 Exendin-4能够保护由于MCAO再灌注后所致的脑缺血再灌注损伤,减少了脑梗死体积,降低皮层凋亡蛋白的相对表达水平,抑制神经元凋亡。结论 Exendin-4可以对MCAO再灌注所致脑缺血/再灌注损伤具有神经保护作用,该作用是通过抑制凋亡蛋白的产生,从而抑制细胞凋亡。     

门冬氨酸钾减轻大鼠可控性皮质打击伤引起的脑损伤

目的 门冬氨酸钾（potassium aspartate,PA）作为一种电解质补充剂,在临床上广泛使用。以往的研 究发现门冬氨酸钾在脑缺血/再灌注大鼠中对细胞凋亡有神经保护的作用。本研究将探讨门冬氨酸 钾对创伤性脑损伤（traumatic brain injury,TBI）是否有保护作用。 方法 T BI通过大鼠可控性皮质打击伤（controlled c ortical i mpact,CCI）产生。门冬氨酸钾组或溶剂对 照组在CCI发生后30 min以腹腔注射给予生理盐水或62.5 mg/kg剂量的PA,观察脑血流灌注量,改良 神经功能缺损评分（modified Neurological Severity Score,mNSS）和皮质损伤体积,并检测脑水肿以及 脑组织三磷腺苷（adenosine triphosphate,ATP）、乳酸含量和钠钾ATP酶活性。 结果 在CCI引起的大鼠皮质损伤中,与溶剂对照组相比,急性给予62.5 mg/kg剂量的PA治疗可以明 显改善神经功能缺损（P＜0.05),降低皮质损伤体积（P＜0.01）,减轻脑水肿（P＜0.05）。此外,与溶 剂对照组相比,门冬氨酸钾治疗组显著减少ATP缺失（P＜0.01）,降低乳酸含量（P＜0.05）,并增加 钠钾ATP酶的活性（P＜0.05）。 结论 PA能通过增加ATP含量和钠钾ATP酶的活性并降低脑水肿,对TBI具有神经保护作用。这为PA 在临床脑损伤时的应用提供了实验证据。     

泊洛沙姆188对大鼠急性硬膜下血肿模型脑组织含水量、NF-κB基因表达的影响

目的研究泊洛沙姆188(P188)对神经细胞的保护作用及其可能机制。方法将72只SD大鼠随机等分成3组,每组24只:对照组大鼠不予任何处理;模型组为急性硬膜下血肿大鼠模型,不予任何治疗;P188组造模成功后,给予P188治疗。各组分别于造模后2h、6h、12h取大鼠血肿区脑组织,测定其含水量;用RT-PCR方法测定造模后12h各组NF-κBmRNA表达水平。结果P188治疗可减轻急性硬膜下血肿模型大鼠脑组织含水量,P188组造模后12h脑含水量为(73.43±0.45)%,与模型组比较,差异具有统计学意义(P0.05)。模型组缺血后NF-κBmRNA表达水平增高,而P188治疗后能明显下调急性硬膜下血肿模型大鼠脑组织NF-κBmRNA的表达。结论P188可通过抑制NF-κBmRNA的表达,对急性硬膜下血肿脑组织产生保护作用。     

毛蕊异黄酮对大鼠脑缺血再灌注损伤的保护作用

目的探讨毛蕊异黄酮对大鼠脑缺血再灌注损伤的保护作用及机制。方法采用大脑中动脉阻塞(MCAO)制备局灶性脑缺血模型,将SD大鼠随机分为MCAO组、溶剂对照组(vehicle组)以及毛蕊异黄酮处理组(calycosin组),缺血再灌注48 h后观察各组神经功能学评分和脑梗死容积大小。术前、术后6 h、24 h、48 h取脑组织样本,分别检测其超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-PX)、丙二醛(MDA)的变化。结果 calycosin组神经功能评分优于MCAO组和vehicle组(P<0.05);calycosin组脑梗死容积小于MCAO组和vehicle组(P<0.05);与MCAO组相比,calycosin组的脑组织SOD、CAT、GSH-PX活力升高,MDA的含量下降,差异均具有显著性(P<0.05)。结论毛蕊异黄酮对大鼠局灶性脑缺血再灌注损伤有一定的神经保护作用,其保护作用与毛蕊异黄酮能降低脑内氧自由基水平、控制脂质过氧化程度有关。     

Minocycline attenuates hypoxia-ischemia-induced neurological dysfunction and brain injury in the juvenile rat

To investigate whether minocycline provides long-lasting protection against neonatal hypoxia-ischemia-induced brain injury and neurobehavioral deficits, minocycline was administered intraperitoneally in postnatal day 4 Sprague-Dawley rats subjected to bilateral carotid artery occlusion followed by exposure to hypoxia (8% oxygen for 15 min). Brain injury and myelination were examined on postnatal day 21 (P21) and tests for neurobehavioral toxicity were performed from P3 to P21. Hypoxic-ischemic insults resulted in severe white matter injury, enlarged ventricles, deficits in the hippocampus, reduction in numbers of mature oligodendrocytes and tyrosine hydroxylase-positive neurons, damage to axons and dendrites, and impaired myelination, as indicated by the decrease in myelin basic protein immunostaining in the P21 rat brain. Hypoxic-ischemic insult also significantly affected physical development (body weight gain and eye opening) and neurobehavioral performance, including sensorimotor and locomotor function, anxiety and cognitive ability in the P21 rat. Treatments with minocycline significantly attenuated the hypoxia-ischemia-induced brain injury and improved neurobehavioral performance. The protection of minocycline was associated with its ability to reduce microglial activation. The present results show that minocycline has long-lasting protective effects in the neonatal rat brain in terms of both hypoxia-ischemia-induced brain injury and the associated neurological dysfunction.     

Minocycline reduces lipopolysaccharide-induced neurological dysfunction and brain injury in the neonatal rat

Preferential brain white matter injury and hypomyelination induced by intracerebral administration of the endotoxin lipopolysaccharide (LPS) in the neonatal rat brain has been characterized as associated with the activation of microglia. To examine whether inhibition of microglial activation might provide protection against LPS-induced brain injury and behavioral deficits, minocycline (45 mg/kg) was administered intraperitoneally 12 hr before and immediately after an LPS (1 mg/kg) intracerebral injection in postnatal day 5 (P5) Sprague-Dawley rats and then every 24 hr for 3 days. Brain injury and myelination were examined on postnatal day 21 and the tests for neurobehavioral toxicity were carried out from P3 to P21. LPS administration resulted in severe white matter injury, enlarged ventricles, deficits in the hippocampus, loss of oligodendrocytes and tyrosine hydroxylase neurons, damage to axons and dendrites, and impaired myelination as indicated by the decrease in myelin basic protein immunostaining in the P21 rat brain. LPS administration also significantly affected physical development (body weight) and neurobehavioral performance, such as righting reflex, wire hanging maneuver, cliff avoidance, locomotor activity, gait analysis, and responses in the elevated plus-maze and passive avoidance task. Treatment with minocycline significantly attenuated the LPS-induced brain injury and improved neurobehavioral performance. The protective effect of minocycline was associated with its ability to attenuate LPS-induced microglial activation. These results suggest that inhibition of microglial activation by minocycline may have long-term protective effects in the neonatal brain on infection-induced brain injury and associated neurologic dysfunction in the rat.     

Delayed administration of interleukin-1 receptor antagonist reduces ischemic brain damage and inflammation in comorbid rats

Many neuroprotective agents have been effective in experimental stroke, yet few have translated into clinical application. One reason for this may be failure to consider clinical comorbidities/risk factors in experimental models. We have shown that a naturally occurring interleukin-1 receptor antagonist (IL-1Ra) is protective against ischemic brain damage in healthy animals. However, protective effects of IL-1Ra have not been determined in comorbid animals. Thus, we tested whether IL-1Ra protects against brain injury induced by experimental ischemia in aged JCR-LA (corpulent) rats, which have clinically relevant risk factors. Male, aged, lean, and corpulent rats exposed to transient (90 minutes) occlusion of the middle cerebral artery (tMCAO) were administered two doses of IL-1Ra (25 mg/kg, subcutaneously) during reperfusion. Brain injury and neuroinflammatory changes were assessed 24 hours after tMCAO. Our results show that IL-1Ra administered at reperfusion significantly reduced infarct volume measured by magnetic resonance imaging (50%, primary outcome) and blood–brain barrier disruption in these comorbid animals. Interleukin-1Ra also reduced microglial activation, neutrophil infiltration, and cytokines levels in the brain. These data are the first to indicate that IL-1Ra protects against ischemic brain injury when administered via a clinically relevant route and time window in animals with multiple risk factors for stroke.     

EPO improved neurologic outcome in rat pups late after traumatic brain injury

In adult rats, erythropoietin improved outcomes early and late after traumatic brain injury, associated with increased levels of Brain Derived Neurotrophic Factor. Using our model of pediatric traumatic brain injury, controlled cortical impact in 17-day old rats, we previously showed that erythropoietin increased hippocampal neuronal fraction in the first two days after injury. Erythropoietin also decreased activation of caspase3, an apoptotic enzyme modulated by Brain Derived Neurotrophic Factor, and improved Novel Object Recognition testing 14?days after injury. Data on long-term effects of erythropoietin on Brain Derived Neurotrophic Factor expression, histology and cognitive function after developmental traumatic brain injury are lacking. We hypothesized that erythropoietin would increase Brain Derived Neurotrophic Factor and improve long-term object recognition in rat pups after controlled cortical impact, associated with increased neuronal fraction in the hippocampus.

Ameliorative effects of GW1929, a nonthiazolidinedione PPARγ agonist, on inflammation and apoptosis in focal cerebral ischemic-reperfusion injury

PPARγ agonist; 2-(Benzoylphenyl)-O-[2-(methyl-2-pyridinylamino) ethyl]-L-tyrosine (GW1929) in focal cerebral ischemic-reperfusion (IR) injury in rats. Focal cerebral IR injury resulted significant brain infarction and neurological deficits in rats. A significant increase in various inflammatory mediators like COX-2, iNOS, MMP-9, TNFα and IL-6 and massive apoptotic DNA fragmentation was also observed in the IR challenged brains. GW1929 treatment significantly attenuated the neurological damage in focal cerebral IR injury. Neuroprotective effects of GW1929 were found to be associated with significant reduction in the COX-2, iNOS, MMP-9, TNFα and IL-6 levels. Together, we have also evaluated the effects of Pioglitazone, a clinically available thiazolidinedione PPARγ agonist, against focal cerebral IR injury. Like GW1929, Pioglitazone also showed beneficial effects in cerebral IR injury associated neurological damage but at the higher dose as compared to GW1929. Neuroprotective effects of PPARγ agonists were found to be associated with significant reduction in TUNEL positive cells in IR challenged brain. In summary, these results suggested the neuroprotective potential of PPARγ agonists in cerebral IR injury and these effects may be attributed to their anti-inflammatory and anti-apoptotic potential.     

促红细胞生成素在脑缺血再灌注损伤中对线粒体的保护作用

目的 探讨促红细胞生成素(EPO)在脑缺血再灌注损伤中对线粒体功能的保护作用. 方法 30只SD大鼠按随机数字表法分为正常对照组、缺血再灌注组和EPO治疗组3组,每组各10只.EPO治疗组和缺血再灌注组用线栓法复制脑缺血再灌注模型.EPO治疗组在缺血再灌注后1、24、48、60 h腹腔注射EPO,剂量为3000 U/kg(用生理盐水以1:1比例稀释),缺血再灌注组腹腔注射同等剂量的生理盐水.正常对照组仅分离颈部动脉,动脉不做栓塞处理.缺血后72h观察各组大鼠脑组织神经细胞线粒体跨膜电位、线粒体丙二醛、超氧化物歧化酶、Na十_K+.ATP酶活性、一氧化氮含量和免疫组化检测海马区Caspase-3阳性细胞数的变化. 结果 EPO治疗组的神经细胞线粒体跨膜电位(77.48±5.93)、超氧化物歧化酶[(96.91±8.66)p,kat/g]、Na+_K+-ATP酶活性[(10.48±2.77)μkat/g]明显高于缺血再灌注组[44.47±17.35、(84.46±8.54)μkat/g、(7.37±2.87)μkat/g],线粒体丙二醛[(37.99±5.38)μmol/g]、一氧化氮含量[(10.18±2.02)μmol/g]、Caspase-3阳性细胞数(66.31±8.09)明显低于缺血再灌注组[(44.83±6.48)μmol/g、(12.12±2.14)μmol/g、74.90±7.42]. 结论 EPO对缺血再灌注损伤脑组织产生保护作用的重要机制之一是保护神经细胞线粒体的功能,其核心是抑制线粒体跨膜电位的下降.     

葛根素预处理对大鼠局灶性脑缺血再灌注损伤的保护作用及机制

目的探讨葛根素预处理对局灶性脑缺血再灌注损伤的保护作用及其可能机制。方法健康成年雄性SD大鼠120只,随机分成5组（n=24）：假手术组（S组）,脑缺血再灌注组（IR组）,Pc-24h100mg组,Pc-24h200mg组,Pc-24h400mg组,其中Pc-24h组于脑缺血前24h给予相应剂量葛根素腹腔注射行单次预处理,采用大脑中动脉线栓法建立局灶性脑缺血再灌注模型,缺血90min,再灌注24h。大鼠清醒后进行神经功能缺陷评分,再灌注24h时处死大鼠,处死后取脑组织,测定脑梗死容积比（BIVP）、脑组织含水量及MDA水平。结果葛根素预处理可以改善大鼠脑缺血再灌注损伤的神经功能缺损评分,降低BIVP、脑组织含水量及MDA水平（P均〈20.01）。其中Pc-24h400mg组减低神经功能缺损评分、BIVP及脑组织含水量明显优于Pc=24h100mg及Pc-24h200mg组（P均〈0.01）,而Pc-24h100mg及Pc-24h200mg组之间无显著差异（P均〉0.05）。结论葛根素预处理可能通过抑制脑水肿及氧化损伤来减轻大鼠局灶性脑缺血再灌注损伤。葛根素预处理的脑保护作用具有一定的量效关系。