大鼠全脑缺血/再灌注模型之比较研究

目的：观察常用大鼠全脑缺血／再灌注模型在缺血及再灌注过程中ｒＣＢＦ及ＥＥＧ的变化。方法：用ｐｅｒｆｌｕｘ－３型多谱勒灌注监测测定局部脑血流量变化。用脑电图仪监测脑电波变化。结果：２ＶＯ组,３ＶＯ组与颈动脉分流组在缺血２５ｍｉｎ时ｒＣＢＦ较Ｖ４ＶＯ组下降明显。３ＶＯ组颈动脉分流组再灌注３０ｓ内ｒＣＢＦ上升较４ＶＯ组及２ＶＯ组变化较慢。     

葛根素对大鼠全脑缺血再灌注后学习记忆障碍保护作用及其机制的研究

目的 探讨葛根素对大鼠全脑缺血再灌注后学习记忆能力的影响及其机制。方法 采用四血管阻断法建立SD大鼠全脑缺血再灌注损伤模型，暗回避反应法测定学习记忆能力，并应用免疫组织化学法、原位末端标记法，检测大鼠全脑缺血再灌注海马CA，区的bcl-2阳性细胞数、凋亡细胞数的动态变化。结果 (1)与再灌注组相比，葛根素组大鼠潜伏期明显延长；(2)脑缺血再灌注后，海马CA1区bcl-2蛋白的表达随再灌注时间不同而变化，缺血20min后再灌注24h达高峰，葛根素组bcl2蛋白的表达于相应的时间点明显增多；(3)脑缺血再灌注后海马CA1区神经元凋亡损伤在再灌注72h损伤最重，葛根素组可减少相应时点神经细胞凋亡数。结论 葛根素对全脑缺血再灌注后大鼠学习记忆能力具有明显的改善作用，其作用机制可能与通过上调bcl-2基因表达从而抑制或延迟脑缺血再灌注后细胞凋亡有关。     

谷氨酰胺对大鼠急性全脑缺血再灌注损伤后小肠黏膜sIgA表达的影响

目的通过建立大鼠全脑缺血再灌注模型,探讨急性全脑缺血再灌注损伤时应用谷氨酰胺后小肠黏膜sIgA表达的影响。方法采用四血管阻断法建立大鼠全脑缺血再灌注动物模型。实验分4组,分别为假手术组（除了不电凝椎动脉和夹闭双侧颈总动脉,其余与盐水对照组相同）、盐水对照组、奥扎格雷钠组和谷氨酰胺组。结果 sIgA表达水平：在6h、12h和24h,与假手术组相比,盐水对照组、奥扎格雷钠组和谷氨酰胺组均有不同程度表达下降,差异有统计学意义（P〈0.05）。与谷氨酰胺组相比,盐水对照组和奥扎格雷钠组表达下降严重,差异有统计学意义（P〈0.05）,而盐水对照组和奥扎格雷钠组相比差异无统计学意义（P〉0.05）。结论大鼠全脑缺血再灌注模型在急性期可造成小肠黏膜的sIgA表达水平下降,应用谷氨酰胺后可提高sIgA表达水平,从而在sIgA表达水平方面减轻大鼠全脑缺血再灌注对小肠黏膜的损伤。     

棕榈油对大鼠局灶性脑缺血再灌注后学习和记忆能力保护作用的实验研究

棕榈油作为世界上第二大食用油,是由热带植物油棕提炼出的一种饱和度较高的油脂,曾经被推测有可能会增加人体血清中胆固醇含量。但经过许多专家进一步的实验论证,发现食用棕榈油不但不会增加血清中的胆固醇,反而有降低胆固醇的趋势;已有实验证实,棕榈油在大鼠高血压和动脉     

大鼠全脑缺血再灌注后ADM表达及其保护机制

目的研究肾上腺髓质素（ADM）在大鼠海马CA1区表达与预缺血处理对缺血脑保护作用的关系。方法将60只大鼠随机分为假手术组、缺血再灌注组、预缺血再灌注组及缺血组,缺血再灌注组和预缺血再灌注组又按再灌注时间再分为再灌注1,2,3及7d组。每组6只动物用改良的四血管阻断法制备大鼠全脑缺血模型。测定各组动物海马CA1区神经元密度及ADM的表达,分析两者的关系。结果假手术组、缺血再灌注组CA1区没有明显细胞坏死,缺血组、预缺血再灌注1d组可见大量细胞坏死;预缺血再灌注2d、3d、7d组亦可见部分细胞坏死,其中预缺血再灌注3d组在预缺血再灌注各组中细胞存活细胞数目最多,其中神经密度密度明显高于缺血组及预缺血再灌注1d、2d和7d组（P〈0.05）。免疫组化显示假手术组、缺血再灌注3d和7d组、预缺血再灌注7d组及缺血组ADM表达水平较低,缺血再灌注1d、2d组及预缺血再灌注3d组ADM表达水平较高,与假手术组,缺血组,缺血再灌注3d和7d组,预缺血再灌注1d、2d和7d组比较差异显著（P〈0.05）。结论 ADM参与了缺血预处理诱导缺血耐受的过程,在一定的时间窗内缺血预处理的神经保护作用存在量效关系。     

学习记忆训练对全脑缺血大鼠认知能力的影响

目的探讨学习记忆训练对全脑缺血大鼠空间学习记忆能力的影响及检测脑源性神经营养因子的变化。方法选用健康雄性SD大鼠90只随机分为假手术组、对照组和训练组,采用改良Pulsinelli’s 4血管闭塞法(4-VO)制作全脑缺血大鼠模型,术后1周以Y型电迷宫训练大鼠,分别在训练7d、14d、21d后应用Y型电迷宫检测比较3组大鼠的空间学习记忆能力的差异;HE染色观察CA1区神经元变化;免疫组化检测脑源性神经营养因子的表达。结果训练21d后,对照组与假手术组和训练组比较,Y型电迷宫全天总反应时间和潜伏期明显延长(P<0.05),错误反应次数明显增多(P<0.05)。对照组CA1区脑源性神经营养因子的光密度值明显低于训练组(P<0.05)。结论学习记忆训练可以改善全脑缺血大鼠的空间学习记忆能力,提示应用学习记忆训练方法可以改善全脑缺血损伤后引起的学习记忆障碍。     

亚低温对大鼠全脑缺血再灌注损伤后海马CA1区c-Jun蛋白表达的影响

目的研究亚低温对大鼠全脑缺血再灌注损伤后海马CA1区神经元的保护作用,并探讨其可能的机制。方法采用四血管阻断法建立大鼠全脑缺血模型。SD大鼠,随机分为假手术组(SH组)、常温组(IR组)和亚低温组(HIR组)。各组在全脑缺血15min后分别再灌注6h、12h、1d、3d,采用苏木素-伊红(HE)染色观察各时间点海马CA1区细胞形态学变化和TUNEL法检测海马CA1区神经元凋亡,免疫印迹检测c-Jun蛋白表达。结果(1)HE染色结果 IR组和HIR组于全脑缺血再灌注后6h,HE染色未见明显改变,IR组缺血再灌注1d时CA1区出现严重改变,3d时损伤最严重,出现细胞数目减少,细胞胞体缩小、胞核固缩深染,损伤严重,排列紊乱,核膜不清,核仁消失。而HIR组海马存活的锥体细胞数较之IR组12h、1d、3d时间点均明显增加(P<0.05)。(2)TUNEL标记IR组于缺血再灌注后6h在海马CA1区阳性细胞开始增多,缺血再灌注1 d时阳性细胞数最多。而HIR组各时间点阳性细胞数均较IR组明显减少(P<0.01)。(3)免疫印迹结果全脑缺血再灌注后6h c-Jun蛋白在IR组海马CA1区表达开始增加,12h达高峰,持续到3d;HIR组在各时间点的表达均弱于IR组(P<0.01)。结论亚低温通过减少海马CA1区c-Jun的表达,抑制海马CA1区神经元的凋亡,可能是亚低温脑保护作用的机制之一。     

丹参对大鼠全脑缺血再灌注后海马CA1区AP-1 DNA结合活性的影响

近来研究表明,AP 1作为一种转录因子,可被短暂性全脑缺血激活,与缺血性脑损伤机制有关。丹参(radixsalviaemiltiorrzhizae ,RSM)为防治缺血性脑血管病的常用中药,其药理作用已有许多报道,如丹参可改善微循环、增加脑组织ATP含量、减轻缺血引起的脑水肿,部分抑制缺血后脑组织c fos基因的表达、拮抗缺血后脑组织的单胺类介质、兴奋性氨基酸的异常变化等。但丹参对脑缺血再灌后转录因子DNA结合活性的影响报道较少。资料和方法:经颈动脉给药,结合生物化学和病理学手段,研究丹参对大鼠全脑缺血再灌后海马CA1区AP 1DNA结合活性变化的影响,…     

纳洛酮对大鼠全脑缺血—再灌注损伤后神经细胞凋亡的影响

目的:本研究旨在探讨纳洛酮对全脑缺血再灌注损伤后神经细胞的保护作用及机制。方法:选取健康成年雄性Wistar大鼠36只。随机分为假手术组,对照组及治疗组。采用大鼠四条血管阻断方法制备大鼠全脑缺血再灌注模型。治疗组于不同开始时间点累积给药纳洛酮。并于缺血再灌注后48小时处死。采用流式细胞分析技术(Fcm)观察海马区细胞凋亡的变化及Bcl-2、Bax的蛋白表达水平。结果:Fcm标记凋亡细胞的变化:治疗组均与对照组有显著统计学差异(P&lt;0.01)。Bcl-2、bax检查表明治疗组与对照组有显著统计学差异(P&lt;0.01)。结论:纳洛酮可减少脑细胞凋亡的发生,这其中可能与纳洛酮早期上调Bcl-2蛋白的表达或通过减轻Bax对Bcl-2活性的抑制从而降低细胞凋亡的发生有关。     

褪黑素对SD大鼠脑缺血再灌注损伤后c-fos表达的影响

目的探讨褪黑素在大鼠脑缺血再灌注损伤中的神经保护作用及可能机制。方法选取45只雄性SD大鼠,分为假手术组(5只)、脑缺血再灌注组(20只)、褪黑素干预组(20只);脑缺血再灌注组和褪黑素干预组根据时间点第6小时、第1天、第3天、第7天分为4个组,每组5只。采用Longa线栓法建立大鼠左侧大脑中动脉栓塞(MCAO)模型,采用HE染色检测脑组织的病理改变,TUNEL染色检测神经细胞的凋亡,免疫组织化学(免疫组化)法及蛋白质印迹法(Western Blotting)观察大鼠脑组织内c-fos表达情况。结果在脑缺血再灌注组的各时间点的HE染色显示,胶质细胞呈现程度不一的增生,神经元出现坏死;褪黑素干预能减轻脑缺血再灌注后胶质细胞增生及神经元的坏死。在TUNEL染色凋亡检测中,脑缺血再灌注组各时间点的神经细胞凋亡升高;褪黑素干预组各时间点的细胞凋亡数低于脑缺血再灌注组(P <0.05)。在免疫组化及蛋白质印迹检测中,脑缺血再灌注组c-fos表达增加,在第1天时达到高峰,之后表达逐步降低;在褪黑素干预组,c-fos表达趋势与缺血再灌注组一致,但表达水平比缺血再灌注组相应时间点低,差异有统计学意义(P <0.05)。结论褪黑素能够减轻脑缺血再灌注后神经元的损伤,降低c-fos的表达,表明褪黑素可能通过调控c-fos的表达在脑缺血再灌注中发挥神经保护作用。     

缺血后处理对大鼠脑缺血再灌注损伤神经保护作用的研究

目的探讨大鼠脑缺血后处理对缺血再灌注损伤后神经元的保护作用。方法健康雄性SD大鼠30只,随机分为假手术组(SO组)、缺血再灌注对照组(MCAO组)、缺血后处理组(IPOC组)3组。采用线栓法制备大鼠MCAO模型及IPOC模型,分别用TTC染色法计算脑梗死体积、流式细胞术和ELISA法观察,对于大鼠缺血半暗带神经细胞凋亡率及血清神经元特异性烯醇化酶(NSE)含量的影响。结果 (1)大鼠脑缺血再灌注后24h,IPOC组较MCAO组梗死体积明显减小(P<0.05);(2)MCAO组大鼠脑缺血再灌注24h细胞凋亡发生率及血清中NSE的含量较SO组显著增加(P<0.01);(3)IPOC组神经元凋亡发生率及血清NSE较MCAO组显著降低(P<0.05或0.01)。结论大鼠脑缺血后处理对缺血再灌注神经元损伤有保护作用。     

水通道蛋白4在大鼠脑缺血再灌注损伤中的作用

目的研究水通道蛋白4(AQP4)在缺血再灌注损伤大鼠脑内表达及作用。方法以大脑中动脉线栓法建立大鼠缺血再灌注模型,采用干湿法测定模型的脑组织含水量及伊文氏蓝含量;免疫蛋白印记(WesternBlot)技术分析在缺血再灌注不同时程脑内AQP4的表达情况,以及AQP4与脑含水量和伊文氏蓝水平的相关性,并与对照组比较。结果与对照组相比,实验组大鼠脑组织含水量及伊文氏蓝水平在缺血再灌注后不同时间点明显高于对照组(P<0.05～0.01);AQP4蛋白表达明显增高(均P<0.05),并随着缺血再灌时间的延长,其表达量亦逐渐增加,在再灌后24～48h达到高峰。缺血再灌注后AQP4脑内的表达与脑组织含水量及伊文氏蓝水平呈正相关(r=0.38、r=0.45,均P<0.05)。结论AQP4的高表达参与了脑缺血再灌注后继发的血脑屏障的开放和脑水肿的发生,是脑水肿产生的重要分子基础。     

亚低温对大鼠脑缺血再灌注损伤的保护研究

目的观察亚低温对大鼠全脑缺血再灌注后海马CAI区神经元凋亡的影响,探讨亚低温对缺血再灌注脑损伤的保护作用。方法SD大鼠30只随机分为对照组（n=10）,常温缺血组（n=10）,亚低温组（n=10）,采用改良的Pulsinelli-Brierley4血管法建立全脑缺血再灌注动物模型,缺血30min后再灌注72h,尼氏体染色观察海马区存活锥体细胞数,TUNEL法检测缺血后海马CAI区神经元凋亡情况,电镜下观察神经细胞形态学改变。结果与对照组比较,常温缺血组的海马CAI区存活的锥体细胞数目减少（P〈0.01）;与常温缺血组比较,亚低温组海马CAI存活的锥体细胞数目明显增多（P〈0.01）。对照组、亚低温组的海马CAI区神经元凋亡数目和凋亡指数明显低于常温缺血组。在电镜下观察亚低温能明显减轻缺血后脑组织病理形态学的损害程度。结论亚低温可以抑制脑缺血再灌注后的神经细胞凋亡,对神经细胞有保护作用。     

Dose-dependent effects of procyanidin on nerve growth factor expression following cerebral ischemia/ reperfusion injury in rats★

BACKGROUND： Recently, grape seed procyanidin （GSP） has been shown to be exhibit antioxidant effects, effectively reducing ischemia/reperfusion injury and inhibiting brain cell apoptosis. OBJECTIVE： To study the effects of GSP on nerve growth factor （NGF） expression and neurological function following cerebral ischemia/reperfusion injury in rats. DESIGN： Randomized controlled study based on SD rats. SETTING： Weifang Municipal People＇s Hospital. MATERIALS： Forty-eight healthy adult SD rats weighing 280-330 g and irrespective of gender were provided by the Experimental Animal Center of Shandong University. GSP derived from grape seed was a new high-effective antioxidant provided by Tianjin Jianfeng Natural Product Researching Company （batch number： 20060107）. Rabbit-anti-rat NGF monoclonal antibody was provided by Beijing Zhongshan Biotechnology Co., Ltd., and SABC immunohistochemical staining kit by Wuhan Boster Bioengineering Co., Ltd. METHODS： The present study was performed in the Functional Laboratory of Weifang Medical College from April 2006 to January 2007. Forty-eight SD rats were randomly divided into the sham operation group, ischemia/reperfusion group, high-dose GSP （40 mg/kg） group, or low-dose GSP （10 mg/kg） group （n = 12 per group）. Ischemia/reperfusion injury was established using the threading embolism method of the middle cerebral artery. Rats in the ischemia/reperfusion model group were given saline injection （2 mL/kg i.p.） once daily for seven days pre-ischemia/reperfusion, and once more at 15 minutes before reperfusion. Rats in the high-dose and low-dose GSP groups were injected with GSP （20 or 5 mg/mL i.p., respectively, 2 mL/kg） with the same regime as the ischemia/reperfusion model group. The surgical procedures in the sham operation group were as the same as those in the ischemia/reperfusion model group, but the thread was approximately 10 mm long, thus, the middle cerebral artery was not blocked. MAIN OUTCOME MEASURES： NGF expression in the     

13-Methyltetradecanoic acid mitigates cerebral ischemia/reperfusion injury

13-Methyltetradecanoic acid can stabilize cell membrane and have anti-inlfammatory, antioxidant and anti-apoptotic effects. Previous studies mainly focused on peripheral nerve injury, but seldom on the central nervous system. We investigated whether these properties of 13-methyltetradecanoic acid have a neuroprotective effect on focal cerebral ischemia/reperfusion injury, and detected the expression of basic ifbroblast growth factor and vascular endothelial growth factor. This study established rat models of middle cerebral artery occlusion/reperfusion injury by ischemia for 2 hours and reperfusion for 24 hours. At the beginning of reperfusion, 13-methyltetradecanoic acid 10, 40 or 80 mg/kg was injected into the tail vein. Results found that various doses of 13-methyltetradecanoic acid effectively reduced infarct volume, mitigate cerebral edema, and increased the mRNA and protein expression of basic ifbroblast growth factor and vascular endothe-lial growth factor at 24 hours of reperfusion. The effect was most signiifcant in the 13-methyltetradecanoic acid 40 and 80 mg/kg groups. The ifndings suggest that 13-methyltetradecanoic acid can relieve focal ischemia/reperfusion injury immediately after reperfusion, stimu-late the upregulation of basic ifbroblast growth factor and vascular endothelial growth factor to exert neuroprotective effects.     

Baicalin attenuates global cerebral ischemia/reperfusion injury in gerbils via anti-oxidative and anti-apoptotic pathways

Baicalin is an important medicinal herb purified from the dry roots of Scutellaria baicalensis Georgi. The present study was undertaken to evaluate the neuroprotective effects of baicalin in gerbils subjected to transient global cerebral ischemic-reperfusion injury. Baicalin at doses of 50, 100 and 200 mg/kg was intraperitoneally injected into the gerbils immediately after cerebral ischemia. Seven days after reperfusion, hematoxylin and eosin (HE) staining was performed to analyze hippocampal CA1 pyramidal damage histopathologically. In addition, in order to understand the potential protective mechanism of baicalin, we examined anti-oxidative enzymes, such superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), non-enzymatic scavenger glutathione (GSH) and measured the content of malondialdehyde (MDA) in hippocampus. The mRNA and protein expressions of BDNF were determined in ischemic hippocampus by real-time RT-PCR and Western blot, respectively. Evidence for neuronal apoptosis was detected by real-time RT-PCR, Western blot and caspase-3 activity measurement. Histopathological examination showed that the administration of baicalin by the dose of 100 and 200 mg/kg significantly attenuated ischemia-induced neuronal cell damage. Reduced level of MDA, obviously elevated activities of SOD and GSH as well as GSH-PX were also found in baicalin-treated groups. Further investigation demonstrated that treatment with baicalin remarkably promoted the expression of BDNF and inhibited the expression of caspase-3 at mRNA and protein levels by real-time RT-PCR and Western blot, respectively. Besides, caspase-3 activity assay also elucidated that the administration of baicalin could significantly suppress caspase-3 in ischemic gerbils hippocampus. Theses findings suggest that baicalin's neuroprotection appears to be associated with its anti-oxidative and anti-apoptotic properties in global cerebral ischemia in the gerbils.     

Chemokine receptor 7 mediates miRNA-182 to regulate cerebral ischemia/reperfusion injury in rats

Aims

Chemokine receptor 7 (CXCR7) exerts protective effects on the brain. MicroRNAs (miRNAs) are involved in cerebral ischemia/reperfusion (I/R) injury, but their involvement in CXCR7-mediated brain protection is unknown. In this study, we investigated the role of miRNAs in CXCR7-mediated brain protection.

Methods

CXCR7 levels in peripheral blood samples from patients with acute ischemic stroke (AIS) and ischemic penumbra area brain tissues from middle cerebral artery occlusion (MCAO) rats after recanalization were measured. An miRNA microarray analysis was performed to examine the expression of miRNAs caused by CXCR7 knockdown in ischemic penumbra area brain tissue in middle cerebral artery occlusion–reperfusion rats and to predict corresponding downstream target genes. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis revealed the most enriched pathways. A dual-luciferase reporter assay confirmed the direct regulation of miR-182 on the target gene TCF7L2. The correlation between TCF7L2 and CXCR7/miR-182 was verified using rescue assays.

Results

CXCR7 expression was upregulated in MCAO rats and mechanical thrombectomy patients with AIS compared to that in controls. The motor and sensory functions of MCAO rats with CXCR7 knockdown further decreased, and the infarct volume and cerebral edema increased. miRNA microarray data showed that seven miRNAs were differentially expressed after shRNA-CXCR7 treatment. The dual-luciferase reporter assay confirmed that miR-182 directly targeted the TCF7L2 gene. Rescue assays confirmed that TCF7L2 is downstream of CXCR7/miR-182. KEGG pathway analysis showed that the Hippo pathway may be a key pathway in CXCR7 upregulation and plays a role in protecting the brain after interventional surgery. Animal experiments have shown that CXCR7-mediated cerebral I/R injury promotes the phosphorylation of key molecules YAP and TAZ in the Hippo pathway.

Conclusion

CXCR7 protects against cerebral I/R injury, possibly via the miR-182/TCF7L2/Hippo pathway. These results indicate that CXCR7 affects cerebral ischemia–reperfusion injury through miRNA regulation and downstream pathways.     

Effect of nicorandil on infarct volume and marker enzyme activity in mitochondria of rats with cerebral ischemia/ reperfusion injury

BACKGROUND: Recent studies have suggested that mitochondrial ATP-sensitive K channel openers could reduce myocardium infarct size, and protect the function of the mitochondria.OBJECTIVE: To investigate the changes of cerebral infarction volume and the activity of marker enzymes in brain mitochondria of rats given the ATP-sensitive K channel opener, nicorandil, before focal cerebral ischemia/reperfusion (I/R).DESIGN, TIME AND SETTING: Randomized, controlled animal experiment, completed at the Brain Scientific Research Center of the Affiliated Hospital of Qingdao University from July to November 2007.MATERIALS: Sixty healthy male Wistar rats weighing 280-300g. Nicorandil, 5-hydroxydecanoate (5-HD) and cytochrome C were purchased from Sigma in the USA. Standard malondialdehyde (MDA) and protein were purchased from Nanjing Jiancheng Biotechnology Institute.METHODS: Sixty rats were randomly divided into a sham operation group, a middle cerebral artery occlusion (MCAO) group, a nicorandil group and a nicorandil 5-HD group. MCAO for 2 hours was performed in the MCAO group, nicorandil group and nicorandil 5-HD group. A total of 5mL saline were given to the MCAO group before MCAO. The nicorandil group was injected with the ATP-sensitive K channel opener nicorandil 10mg/kg intraperitoneally 30 minutes before MCAO. The nicorandil 5-HD group was injected with 5-HD 10mg/kg intravenously 15 minutes before the same treatment as the nicorandil group.MAIN OUTCOME MEASURES: Infarct volume by total brain slice calculation, activities of succinate dehydrogenase (SDH) and cytochrome oxidase (CO), and content of MDA were observed at 22 hours of reperfusion after 2 hours MCAO.RESULTS: Sixty rats were included in the final analysis, without any loss. (1) Infarct volume: compared with the MCAO group and nicorandil 5-HD group, the percentage of infarct volume was significantly decreased in the nicorandil group (P<0.01). (2) The content of MDA, expression of SDH and CO in brain: the expressions of SDH and CO in the sham operation group were significantly lower than those in the MCAO, nicorandil and nicorandil 5-HD groups (P<0.01). The expressions of SDH and CO in the nicorandil group were significantly higher than those in the MCAO and nicorandil 5-HD groups (P<0.05). The content of MDA in the brain of the nicorandil group was significantly lower than those in the MCAO and nicorandil 5-HD groups (P<0.01).CONCLUSION: Nicorandil can significantly reduce the infarct volume in a rat MCAO model, increase the activity of the mitochondria and protect against cerebral I/R injury.     

Effect of nicorandil on infarct volume and marker enzyme activity in mitochondria of rats with cerebral ischemia/ reperfusion injury★

BACKGROUND： Recent studies have suggested that mitochondrial ATP-sensitive K＋ channel openers could reduce myocardium infarct size, and protect the function of the mitochondria. OBJECTIVE： To investigate the changes of cerebral infarction volume and the activity of marker enzymes in brain mitochondria of rats given the ATP-sensitive K＋ channel opener, nicorandil, before focal cerebral ischemia/reperfusion （I/R）. DESIGN, TIME AND SETTING： Randomized, controlled animal experiment, completed at the Brain Scientific Research Center of the Affiliated Hospital of Qingdao University from July to November 2007. MATERIALS： Sixty healthy male Wistar rats weighing 280-300 g. Nicorandil, 5-hydroxydecanoate （5-HD） and cytochrome C were purchased from Sigma in the USA. Standard malondialdehyde （MDA） and protein were purchased from Nanjing Jiancheng Biotechnology Institute. METHODS： Sixty rats were randomly divided into a sham operation group, a middle cerebral artery occlusion （MCAO） group, a nicorandil group and a nicorandil＋5-HD group. MCAO for 2 hours was performed in the MCAO group, nicorandil group and nicorandil＋5-HD group. A total of 5 mL saline were given to the MCAO group before MCAO. The nicorandil group was injected with the ATP-sensitive K＋ channel opener nicorandil 10 mg/kg intraperitoneally 30 minutes before MCAO. The nicorandil＋5-HD group was injected with 5-HD 10 mg/kg intravenously 15 minutes before the same treatment as the nicorandil group. MAIN OUTCOME MEASURES： Infarct volume by total brain slice calculation, activities of succinate dehydrogenase （SDH） and cytochrome oxidase （CO）, and content of MDA were observed at 22 hours of reperfusion after 2 hours MCAO. RESULTS： Sixty rats were included in the final analysis, without any loss. （1） Infarct volume： compared with the MCAO group and nicorandil＋5-HD group, the percentage of infarct volume was significantly decreased in the nicorandil group （P 〈 0.01）. （2） The content of MDA, expression of