左卡尼汀对局灶性脑缺血再灌注损伤大鼠ATP酶活性的影响

目的研究左卡尼汀对局灶性脑缺血再灌注损伤的保护作用。方法采用线栓法制备局灶性脑缺血(MCAO)再灌注损伤大鼠模型,观察左卡尼汀对大鼠脑组织ATPase活性的影响。结果左卡尼汀各剂量组均能提高缺血再灌注大鼠脑组织ATPase的活性。结论左卡尼汀对局灶性脑缺血再灌注损伤的保护机制可能与其促进脑能量代谢,提高脑组织ATP酶活性,维持钠泵、钙泵的稳定有关。     

肢体反复短暂缺血预处理在大鼠脑缺血再灌注损伤中的保护作用

目的 探讨肢体反复短暂缺血预处理(LIP)在大鼠脑缺血再灌注损伤中可能的脑保护机制.方法 随机将42只成年健康雄性Wistar大鼠分为7组,假手术组、脑缺血组、脑缺血再灌注组、预处理0 h组、预处理6 h组、预处理12 h组、预处理24 h组.采用线栓法制备大脑中动脉缺血及缺血再灌注模型,重复夹闭大鼠双侧股动脉4 次(每次10 min,间隔10 min) 作为LIP,采用生化方法测定各组脑组织中丙二醛(MDA)、超氧化物歧化酶(SOD)、三磷酸腺苷(ATP)酶的含量;HE染色观察大鼠脑组织的病理改变.结果 肢体反复短暂缺血预处理组可明显减少MDA的含量,升高SOD活性,增加ATP含量,尤以预处理0 h和6 h组为著,同其余预处理组及对照组相比差异有统计学意义(P<0.05).结论 肢体缺血预处理可提高脑缺血大鼠的SOD活性、降低MDA含量、促进ATP的生成,推知反复短暂的肢体缺血预处理对大鼠脑缺血再灌注损伤有保护作用,它可通过提高脑组织抗氧化酶活性、提高线粒体能量,抑制氧自由基产生及脂质过氧化反应来发挥作用.     

局灶性缺血再灌注大鼠脑线粒体损伤的实验研究

采用大鼠大脑中动脉缺血（MCAO）再灌注模型，观察缺血再灌注不同时相（分为五组）脑线粒体损伤的变化规律。结果为脑缺血再灌注后线粒体基质游离钙含量（MCa）明显高于假手术组Na^＋、K^＋-ATP酶、Ca^2＋、Mg^＋-ATP酶活性明显下降，且随时间的延长下降明显；再灌注0．5h的MDA和SOD均元明显变化，再灌注1h后线粒体MDA含量明显升高，SOD活性明显下降。说明脑缺血再灌注线粒体损伤与线粒体钙超载及线粒体内膜氧化磷酸化有关。     

羚蝎胶囊对大鼠局部脑缺血再灌注模型脑组织ATP酶的影响

目的了解羚蝎胶囊对脑缺血再灌注大鼠脑组织能量代谢的影响.方法将大鼠分为假手术组、模型组、治疗组3组,用MCAO法复制大鼠局部脑缺血再灌注模型,观察各组大鼠神经功能缺损积分和脑组织ATP酶的变化.结果治疗组再灌注后3 h神经功能缺损积分显著低于模型组,治疗组Na -K -ATPcase、Ca2-ATPcase、Mg2 -ATPcase活性均较模型组高(P＜0.01或P＜0.05).结论羚蝎胶囊能提高大鼠局部脑缺血再灌注模型脑组织ATP酶的活性.     

丹红注射液对大鼠脑缺血再灌注后损伤的保护作用及机制研究

目的研究丹红注射液对脑缺血再灌注后神经功能恢复及保护作用机制。方法采用改良线拴法制做大脑中动脉缺血2h再灌注模型,随机分为假手术组、缺血再灌注组、缺血再灌注加丹红注射液组,缺血再灌注组及缺血再灌注加丹红注射液组每日尾静脉注射相同剂量的0．9％氯化钠溶液或丹红注射液（100mg／kg）,观察给药7d后各组大鼠神经行为变化、脑梗死体积,并测定脑组织含水量、丙二醛（MDA）、单胺氧化酶（MAO）活性、超氧化物歧化酶（SOD）活性。结果缺血再灌注加丹红注射液组术后7d时神经功能恢复优于缺血再灌注组,脑梗死体积均小于缺血再灌注组,缺血再灌注加丹红注射液组脑含水量低于缺血再灌注组和假手术组,差异有显著性意义（P〈0．05）。缺血再灌注加丹红注射液组能降低脑组织MAO活力、MDA含量,提高SOD活性,同缺血再灌注组相比差异有显著性（P〈0．05）。结论丹红注射液能促进脑缺血后神经功能恢复,减小梗死体积,对大鼠脑缺血再灌注损伤有一定保护作用。     

金纳多对脑缺血再灌注损伤大鼠MMP-9活性和血脑屏障通透性的影响

目的探讨金纳多对大鼠脑缺血再灌注损伤的保护作用。方法采用线栓法制备大鼠局灶性脑缺血再灌注损伤模型,将成模大鼠随机分为假手术组、缺血再灌注组、金钠多治疗组,各组按缺血再灌注6、12、24 h三个时间点分为3个亚组,每组10只。用RT-PCR方法测定损伤侧脑组织中MMP-9活性变化,用伊文思蓝方法测定同侧脑组织血脑屏障通透性。结果 (1)随缺血再灌注时间延长,MMP-9含量、EB含量开始逐渐增加,各组之间表达差异均具有统计学意义(P<0.05)。(2)金纳多治疗组MMP-9活性及EB含量各个时间点明显低于缺血再灌注组(P<0.05)。结论金纳多通过抑制脑缺血再灌注大鼠MMP-9的活性,减轻血脑屏障通透性,可能是其发挥脑保护作用的机制之一。     

黄体酮对局灶性脑缺血再灌注大鼠脑组织SOD及MDA水平的影响

目的探讨黄体酮对局灶性脑缺血大鼠脑组织匀浆超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量的影响。方法采用线栓法制作左侧大脑局灶性脑缺血模型(MCAO模型),将SD大鼠随机分为假手术组、手术组、溶剂治疗组、黄体酮组,术后3、6、12、24 h断头取脑,制备脑匀浆,用生化方法检测MDA含量及SOD活性。结果与假手术组比较,缺血2 h再灌注3 h后,手术组和溶剂治疗组脑组织SOD活性开始下降,再灌注24 h达到最低,与手术组比较,再灌注6、12、24 h时黄体酮组脑组织的SOD活性显著升高(P<0.05)。与假手术组比较,缺血2 h再灌注3 h后,手术组和溶剂治疗组脑组织MDA含量开始升高,再灌注12 h时达到高峰,24 h时仍高,与手术组比较,黄体酮组脑组织的MDA含量在6、12、24 h均显著降低(P<0.05,P<0.05,P<0.01)。结论黄体酮可通过一定的抗氧化作用,对脑缺血再灌注大鼠脑组织产生保护作用。     

二氮嗪对大鼠缺血再灌注损伤脑组织线粒体ATP酶活性的影响

目的 探讨线粒体ATP敏感性钾通道开放剂二氮嗪对大鼠局灶性脑缺血再灌注损伤脑组织线粒体ATP酶活性的影响.方法 采用改良线栓法建立大鼠局灶性大脑中动脉缺血再灌注损伤模型.将21只Wistar雄性大鼠随机分为假手术组(N组)、缺血再灌注组(IR组)、二氮嗪干预组(DZ组).缺血1 h再灌注24 h后留取标本,测定脑组织线粒体Na+-K+-ATP酶、Ca2+-Mg2+-ATP酶活性的变化.结果 与假手术组比较,缺血再灌注组Na+-K+-ATPase、Ca2+-Mg2+-ATP酶活性明显降低(P<0.05);二氮嗪干预组Na+-K+-ATP酶、Ca2+-Mg2+-ATP酶活性均较缺血再灌注组有不同程度的提高(P<0.05).结论 二氮嗪预处理能通过提高脑组织线粒体Na+-K+-ATP酶、Ca2+-Mg2+-ATP酶活性,减轻脑缺血再灌注损伤,保护神经元线粒体的功能,有效维持大脑能量代谢,发挥脑保护作用.     

辛伐他汀对大鼠局灶性脑缺血的线粒体保护作用

目的：探讨辛伐他汀对局部脑缺血损伤大鼠的保护作用及其线粒体机制。方法：96只大鼠随机分为假手术组、缺血再灌注组和辛伐他汀处理组，每组32只。建立大鼠大脑中动脉闭塞（MCAO）模型，观察大鼠神经功能、梗死体积、脑组织线粒体超微结构的改变；检测线粒体细胞色素c氧化酶（COX）、琥珀酸脱氢酶（SDH）活性，Ca^2＋含量，以及血清降钙素基因相关肽（CGRP）含量。结果：与假手术组相比较，缺血再灌注组各项指标均有显著改变；与缺血再灌注组比较，辛伐他汀能明显提高脑缺血大鼠的神经功能评分（P〈0．01），缩小梗死体积（P〈0．01），改善脑组织线粒体结构，并提高脑组织线粒体SDH活性（P〈0．05），提高COX活性（P〈0．01），降低脑组织线粒体Ca^2＋的含量（P〈0．01），提高血清CGRP水平（P〈0．05）。结论：辛伐他汀可能通过其抗氧化效应，提高脑组织线粒体SDH、COX活性及血清CGRP水平，减轻钙超载，缩小梗死体积，改善神经功能，从而对大鼠局灶性脑缺血起保护作用。     

头孢曲松钠对脑缺血再灌注模型大鼠的脑保护作用

目的评价头孢曲松钠对脑缺血再灌注损伤的脑保护作用。方法 36只雄性SD大鼠随机分为假手术组、生理盐水组、头孢曲松钠组,每组8只。采用线栓法制作大脑中动脉缺血再灌注模型。用RT-PCR检测TNF-α的表达,TTC染色评估脑缺血体积,用Bederson法对大鼠进行神经功能评分,HE染色观察各组大鼠脑皮质组织学变化。结果头孢曲松钠组脑缺血体积明显缩小、TNF-α表达减少、神经功能评分好于生理盐水组,脑组织坏死及水肿情况较生理盐水组减轻。结论头孢曲松钠预处理能减轻大鼠缺血再灌注后脑损伤。     

脑缺血再灌注肾脏组织损伤老年大鼠ATP酶和自由基代谢的变化及其意义

目的 从ATP酶活性变化和自由基损伤方面研究老年大鼠脑缺血再灌注肾脏损伤机制。方法 青年（5-6月龄）和老年（20-22月龄）大鼠均分为模型组和正常对照组。观察大鼠全脑缺血30min再灌注60min后肾脏组织形态和肌酐（Cr)。尿素氮（BUN），丙二醛（MDA）含量及超氧化物岐化酶（SOD），ATP酶的活性，结果 青年和老年模型组大鼠肾脏组织形态和功能均出现明显的病理改变，老年模型组较青年模型组严重，青年模型组和老年模型组肾脏组织MDA含量和MDA/SOD比值分别高于青年对照组和老年对照组，老年模型组肾脏组织Na^ -K^ -ATP酶和Ca^2 -ATP酶活性低于青年模型组；老年对照组肾脏Ca^2 -ATP酶活性低于青年对照组，老年模型组肾脏Ca^2 -ATP酶活性低于老年对照组。结论 脑缺血再灌注肾脏损伤老年大鼠较青年大鼠严重。ATP酶活性降低和自由基损伤可能是其主要机制之一，由于老年大鼠ATP酶活性和自由基代谢的增龄变化使这些病理改变较青年明显并具有一定特点。     

注射用尼莫地平脂质体对大鼠局灶性脑缺血再灌注损伤的影响

目的:探讨注射用尼莫地平脂质体对大鼠局灶性脑缺血再灌注损伤的影响.方法:70只SD大鼠分为注射用尼莫地平脂质体(nimodipine liposomes for injection,NDLI)1.00mg/kg组、NDLI 0.50mg/kg组、NDLI 0.25mg/kg组、尼莫地平组(1.00 mg/kg)、溶媒组(10 mL/Kg)、假手术组和缺血模型组.复制大鼠大脑中动脉闭塞模型.对各组大鼠进行行为学评分,检测梗死灶体积、脑含水量、脑匀浆生化指标和脑组织学.结果:NDLI 1.00 mg/kg、0.50 mg/kg和0.25 mg/kg均能够显著改善局灶性脑缺血大鼠的行为学评分,缩小梗死灶体积,减少脑含水量,提高脑组织内Na+,K+-ATP酶、Ca2+-ATP酶、谷胱甘肽和超氧化物歧化酶活性,降低丙二醛、乳酸和一氧化氮含量,并能改善脑组织损伤.结论:NDLI对大鼠局灶性脑缺血再灌注损伤有保护作用.     

Cardiac ischemia causes inhibition of the Na/K ATPase by a labile cytosolic compound whose production is linked to oxidant stress

OBJECTIVE: Intracellular Na rises rapidly during cardiac ischemia and this has been attributed to the combination of increased influx of Na via sodium-proton exchange and decreased activity of the Na/K ATPase. The aim of these studies was to investigate the effects of ischemia on Na/K ATPase function in Langendorff-perfused rat hearts. METHODS: Na/K ATPase activity was determined by measuring ouabain-sensitive phosphate generation from ATP by cardiac homogenates. RESULTS: Global ischemia (15 and 30 min) caused a substantial reduction in Na/K ATPase function despite high substrate availability in the assay. When sarcolemmal membranes were purified away from the cytosol a profound activation of the Na/K ATPase was revealed following ischemia, indicating that the inhibition was due to the cytosolic accumulation of an inhibitor of Na/K ATPase. The half-life of the inhibitor in cardiac homogenates was 10+/-3 min at room temperature. Perfusion with the antioxidant MPG (1 mmol/l) reduced the accumulation of this inhibitor, however MPG was without effect on Na/K ATPase function when added directly to the Na/K ATPase activity assay. While the inhibitor reduced the activity of cardiac and brain forms of the Na/K ATPase in bioassay experiments, no effect was observed on the renal and skeletal muscle forms of the enzyme. CONCLUSIONS: An unstable cardiac and brain-specific inhibitor of the Na/K ATPase whose production is linked to oxidant stress, accumulates intracellularly during ischemia. Intracellular Na is a primary determinant of electro-mechanical recovery on reperfusion, so inhibition of the Na/K ATPase by this compound may be crucial in determining recovery from ischemia.     

CGRP对大鼠全脑缺血再灌注ATP酶活性的影响

目的研究降钙素基因相关肽(CGRP)对大鼠全脑缺血再灌注(I/R)脑组织ATP酶活性变化的影响及神经保护机制.方法45只SD大鼠,随机分为假手术组、对照组、CGRP)组.采用四血管阻断方法制备SD大鼠全脑I/R模型,定磷比色法测定全脑I/R及全脑I/R CGRP治疗大鼠海马Na ,K -ATP、Ca2 -ATP酶活性.结果与假手术组比较,大鼠全脑I/R后海马Na ,K -ATP、Ca2 -ATP酶活性降低.CGRP对I/R后海马Na ,K -ATP、Ca2 -ATP酶活性降低有明显的抑制作用.结论CGRP对大鼠全脑I/R脑组织损伤有保护作用.     

Na+ accumulation increases Ca2+ overload and impairs function in anoxic rat heart

Maintenance of low coronary flow (1 ml/min) during 40 or 70 min of anoxia maintained function and prevented Ca2+ overload during reoxygenation in isolated rat hearts. In comparison, recovery from 40 min of global ischemia resulted in only 20% of preischemic function and an increase in end-diastolic pressure (LVEDP) to 39 mmHg. Reperfusion Ca2+ uptake rose from 0.6 to 10.2 mumol/g dry tissue. Intracellular Na+ (Nai+) increased from 13 to 61 mumol/g dry tissue after 40 min of global ischemia, but was unchanged in hearts with low flow anoxia. When glucose and pyruvate were omitted from buffer used for anoxic perfusion, recovery was only 15% of preanoxic values, LVEDP rose to 32 mmHg, and reperfusion Ca2+ uptake was 7.2 mumol/g dry. In addition, Nai+ increased (47.4 mumol/g dry tissue) and ATP was depleted (1.0 mumol/g dry tissue) in the absence of substrate. In anoxic hearts supplied substrate, Nai+ stayed low (12 mumol/g dry tissue) and ATP was preserved (11.6 mumol/g dry tissue). Addition of ouabain (100 or 200 microM) and provision of zero-K+ buffer increased Nai+ and resulted in impaired functional recovery, increased LVEDP, and greater reperfusion Ca2+ uptake. These interventions also decreased energy availability in anoxic hearts. To distinguish between effects of Na+ accumulation and ATP depletion, monensin, a Na+ ionophore, was added during low flow anoxia. Monensin increased Nai+, decreased functional recovery and increased reperfusion Ca2+ uptake in a dose-dependent manner (1-10 microM) without changing ATP content. These results suggested that reduction of Nai+ accumulation by maintenance of Na+, K+ pump activity was the major mechanism of the beneficial effects of low coronary flow on reperfusion injury.     

Characteristics of inhibition of human renal adenosine triphosphatases by cisplatin and chloroplatinic acid

Cisplatin and chloroplatinic acid were examined for in vitro inhibition of human renal microsomal adenosine triphosphatases activated by Na+ + K+ + Mg2+, Mg2+, and Ca2+. The concentrations of cisplatin to inhibit 50% of activity (I50) were approximately 7 X 10(-4) M for all enzymes studied; I50s of chloroplatinic acid were on the order of 10(-5) M for Na+ + K+ + Mg2+ ATPase and Ca2+ ATPase and 10(-7) M for Mg2+ ATPase in the presence of Na+ + K+ + ouabain. Inhibition of Na+ + K+ + Mg2+ ATPase by cisplatin or chloroplatinic acid was reversible and was not altered by varying Na+, K+, or Mg2+ concentrations; ATP or MgATP increased inhibition by cisplatin but not by chloroplatinic acid; acidic pH of 6.8 lowered inhibition by chloroplatinic acid but not by cisplatin. Cysteine, glutathione (-SH reagents), and ascorbic acid greatly reduced inhibition of all enzymes studied by chloroplatinic acid; in the case of cisplatin, -SH reagents had only a minimal protective effect but ascorbic acid somewhat increased inhibition. Methionine greatly increased inhibition by cisplatin but provided minimal protection in the case of chloroplatinic acid. In view of the hypothesis that inhibition of renal Na+ + K+ ATPase may be associated with tubular damage, the inhibition of Na+ + K+ ATPase may be relevant to the mechanism of platinum toxicity.     

Effect of Ischemia—Reperfusion on Na+,K+-ATPase Expression in Human Liver Tissue Allograft: Image Analysis by Confocal Laser Scanning Microscopy

We have analyzed the effect of ischemia-reperfusion on expression of hepatic Na+,K+-ATPase on bile canalicular (BCM) and basolateral membranes (BLM) in human liver allografts using confocal laser scanning microscopy imaging. Na+, K+-ATPase, an integral membrane enzyme, plays a key role in the physiology and structure of hepatocytes, where it maintains the electrochemical gradients for Na+ and K+ across the cell membrane. The concentrations of these ions as well as their gradients regulate the active transport across the plasma membrane for bile acid and water from sinusoidal to canalicular membranes. In addition, Na+,K+-ATPase is also involved in cellular structure because of its close relationship with submembrane microfilaments and its implication in tight junction assembly. Therefore, Na+,K+-ATPase appears as an indicator of tissue viability and hepatic functionality during liver transplantation. Its localization and its function in BCM are still controversial. As in previous studies, we found an enzyme expression in both BLM and BCM. We show that ischemia induced a decrease in Na+,K+-ATPase expression only in BCM. This result could be explained by the differences in biochemical membrane environment between basolateral and bile canalicular Na+,K+-ATPase. Membrane lipid fluidity, which is more elevated in BLM than in BCM, could protect the enzyme during ischemia. After reperfusion, Na+,K+-ATPase expression was strongly decreased in both BCM and BLM. This alteration following reperfusion is probably due to multiple factors: direct alteration of the enzyme catalytic subunit and modification of its environment and membrane lipid fluidity by free radicals and changes in ATP levels and ionic distribution. This important decrease in Na+,K+-ATPase expression of both BLM and BCM could disturb not only hepatic secretory function but also cellular volume and structure during the postoperative period.     

Blocking Na(+)-H+ exchange by cariporide reduces Na(+)-overload in ischemia and is cardioprotective

In myocardial ischemia, rapid inactivation of Na(+)-K(+)-ATPase and continuing influx of sodium induce Na(+)-overload which is the basis of Ca(2+)-overload and irreversible tissue injury following reperfusion. The Na(+)-H(+)-exchanger of subtype 1 (NHE-1) is assumed to play a major role in this process, but previously available inhibitors were non-specific and did not allow to verify this hypothesis. Cariporide (HOE 642) is a recently synthesized NHE-1 inhibitor. We have investigated its effects on Na+ homeostasis (23Na NMR spectroscopy), cardiac function and energy metabolism (31P NMR) in ischemia and reperfusion. In the well-oxygenated, isolated guinea-pig heart, cariporide (10 microM) had no effect on intracellular Na+, pH or cardiac function. NHE-1 inhibition by cariporide was demonstrated using the NH4Cl prepulse technique. When hearts were subjected to 15 min of ischemia, cariporide markedly inhibited intracellular Na(+)-accumulation (1.3 +/- 0.1 vs 2.1 +/- 0.1-fold rise) but had no effect on the decline in pH. In reperfusion, NHE-1-blockade significantly delayed pH recovery. With longer periods of ischemia (36 min), cariporide delayed the onset of contracture, reduced ATP depletion, Na(+)-overload and again had no effect on pH. In reperfusion, hearts treated with cariporide showed an improved recovery of left ventricular pressure (60 +/- 1 vs 16 +/- 8 mmHg): end-diastolic pressure was normalized and phosphocreatine fully recovered, while there was only a partial recovery in controls. The data demonstrate that Na(+)-H(+)-exchange is an important port of Na(+)-entry in ischemia and contributes to H(+)-extrusion in reperfusion. By reducing Na(+)-overload in ischemia and prolonging acidosis in reperfusion, NHE-blockade represents a promising cardioprotective principle.     

VEGF用于急性脑梗死神经元保护及再生的实验研究

目的探讨血管内皮生长因子（VEGF）在急性脑梗死中神经元保护及再生作用。方法48只SD大鼠，随机分为4组，利用MCAO模型。A组（12只），缺血1h后再灌注24h＋生理盐水，对照组；B组（12只），缺血1h后再灌注1h＋VEGF；C组（12只），缺血1h后再灌注12h＋VEGF；D组（12只），缺血1h后再灌注24h＋VEGF。模型成功后侧脑室注射rrVEGF164，VEGF注射后连续3d分别腹膜下注射BrdU6mg/100g。术后第7天，取脑切脑片。分别TTC染色，HE染色。免疫组化观察。结果VEGF，Tunnel染色凋亡细胞阳性数，BrdU阳性细胞数，在缺血再灌注12h，24h组与对照组相比，阳性细胞数有统计学差异。结论VEGF在急性脑梗死后有抗细胞凋亡及神经元保护作用，并有促进缺血后神经元再生作用。     

Intracellular magnesium during myocardial ischemia and reperfusion: possible consequences for postischemic recovery

Magnesium (Mg2+) is an important regulator of cell energy metabolism, since only MgATP can serve as a substrate for ATP utilizing processes. We used 31P NMR spectroscopy to determine the complexation of ATP with Mg2+ and intracellular free Mg2+ (Mgf) in isolated rat hearts during control perfusion, ischemia and reperfusion. Atomic absorption spectrophotometry was used to determine preischemic and postischemic tissue Mg2+ and release of Mg2+ into the coronary effluent during reperfusion. Mgf increased from 0.60 mmol/l during control perfusion to greater than 6.5 mmol/l after 15 min of ischemia, while we estimated that at that time 6.7 mmol/l Mg2+ had been liberated from ATP. Less than 2% of cellular Mg2+ was released to the effluent during reperfusion after 30 min of ischemia. From spectra obtained during reperfusion the fraction of ATP that was bound to Mg2+ was calculated to be approximately 96% (compared to 94% during control perfusion), indicating that intracellular Mg2+ did not limit the metabolic use of the newly produced ATP. Mgf remained elevated during reperfusion (0.85 mmol/l). We conclude that intracellular Mg2+ deficiency due to leakage of Mg2+ to the extracellular space does not play a role in the poor postischemic recovery in this isolated rat heart model. Nevertheless, high Mg2+ prior to ischemia or during reperfusion may well be protective, due to interactions of Mg2+ with the sarcolemma or intracellular sites, affecting Ca2+,K+ and Na+ distribution and fluxes.