缺血预处理对肠缺血再灌注损伤的保护作用

目的观察肠缺血预处理（IPC）对缺血再灌注（I／R）损伤的保护作用．探讨IPC在肠I／R损伤中的作用机制。方法对大鼠肠系膜上动脉进行4次循环的5min夹闭／Smin开放（即IPC），24h后实施缺血30min再灌注24h，制作I／R损伤模型。检测IPC后肠组织一氧化氮（NO）含量（以NO2^-／NO3^-代表）、超氧化物歧化酶（SOD）、丙二醛（MDA）的含量及观察肠肌间神经丛一氧化氮合成酶（NOS）阳性神经元的变化，检测血清NO及血浆二氨氧化酶（DAO）．采用Chiu评分法观察肠组织损伤情况。结果IPC后肠组织NO、SOD含量下降．而MDA含量明显升高，肠肌间丛NOS阳性神经元数明显降低，DAO水平明显降低，肠组织损伤程度明显减轻。结论IPC对I／R损伤有明显保护作用，其机理与灭活了氧自由基，降低NO含量有关。     

大鼠肝缺血再灌注损伤时脑组织损伤机制的探讨

缺血再灌注损伤是一种全身性反应，某个器官的缺血再灌注损伤可引起其他器官不同程度的损害，即远隔器官的次级损伤。研究表明，肝缺血再灌注（I／R）损伤不仅导致肝功能衰竭，也可引起心、肺、肾等脏器的损伤，且损伤主要发生在再灌注阶段。脑组织是最易受影响的器官之一，肝I／R可引起脑组织损伤。本实验旨在观察肝I／R损伤时c-fos基因、诱导型一氧化氮合酶（iNOS）在脑组织中表达和髓过氧化物酶（MPO）、丙二醛（MDA）水平变化及相互关系，并以琥珀酸脱氢酶（SDH）、三磷酸腺苷（ATP）酶、乳酸脱氢酶（LDH）、乳酸（LD）等指标的变化，探讨肝I／R损伤时脑组织能量代谢的变化及其可能的机制。     

缺氧预处理对大鼠心脏的影响及保护机制的研究

目的探讨丝裂素活化蛋白激酶家系（MAPKS）对大鼠心肌缺血／再灌注（I／R）损伤心肌的保护作用。方法制备在体心肌I／R模型，将实验动物分为3组：假手术（sham）组、I／R组、缺氧预处理（HPC）组。分别于手术24h、14d后观察HPC对血压、心功能、梗死面积及细胞外信号调节激酶（V．RKS）、蛋白激酶P38（P38MAPK）、应激活化蛋白激酶（SAPK）的活性。结果与I／R组比较，HPC明显改善大鼠I／R后的心功能，缩小梗死面积，ERKS及P38MAPK活性增加，而SAPK活性降低。结论缺氧预处理对大鼠心肌I／R损伤心肌有明显保护作用。ERK和P38MAPK参与了HPC的心肌保护作用，而SAPK．在HPC中可能是一个不利因素。     

叔丁基羟基茴香醚对衰老大鼠肾脏缺血/再灌注损伤的保护作用

目的观察老年大鼠肾脏缺血／再灌注（I／R）模型中肾小管上皮细胞的损伤变化，探讨ROS清除剂对I／R损伤的保护作用。方法27月龄大鼠分别随机分为假手术组、I／R模型组、活性氧清除剂——叔丁基羟基茴香醚（BHA）干预组。夹闭双侧肾动脉30min再灌注18h制成I／R模型。观察肾功能、肾脏病理改变、肾小管上皮细胞凋亡情况，检测肾组织caspase-3，测定肾组织脂质过氧化物丙二醛（MDA）含量和超氧化物歧化酶（SOD）活性。结果（1）肾脏I／R损伤时，老年大鼠肾功能明显减退，肾组织病理改变比较明显，大量肾小管上皮细胞凋亡，肾组织caspase-3、肾组织中MDA含量增加、SOD活性下降（P〈0．05）。（2）BHA能明显的改善肾功能、组织病理改变和凋亡相关指标（P〈0、05）；BHA能减少组织中MDA含量，部分恢复组织中SOD含量。结论老年大鼠肾脏I／R损伤时肾小管上皮细胞凋亡增加，肾功能减退。ROS堆积后，线粒体损伤导致肾小管上皮细胞凋亡。清除ROS可以抑制肾小管上皮细胞凋亡，减轻I／R损伤。     

粉防己碱对缺血再灌注大鼠心肌损伤的保护作用及机制探讨

48只雄性SD大鼠，随机分为Sham组（假手术组）、I／R组（缺血再灌注组）和Tet组（手术与I／R组相同，术前20min腹腔注射粉防己碱3mg／kg）。检测再灌注结束后三组大鼠血清中乳酸脱氢酶（LDH）活性、心肌组织丙二醛（MDA）和超氧化物歧化酶（SOD）水平及心肌梗死范围（IS／AAR），应用透射电镜观察心肌超微结构变化。结果与I／R组相比，Tet组大鼠心肌LDH活性值和MDA水平明显降低，SOD水平升高，心肌梗死范围减小。与I／R组相比，Tet组透射电镜下心肌细胞形态改变显著减轻，肌原纤维排列较整齐，线粒体嵴光滑。认为粉防己碱对大鼠再灌注损伤心肌具有保护作用，其保护机制可能与其抗氧自由基作用有关。     

吸入一氧化氮对犬烟雾吸入性损伤肺组织ACE活性的影响

血管紧张素转换酶（ACE）已作为肺毛细血管内皮细胞受损的指示性指标，本研究旨在评价吸入一氧化氮（NO）对吸入性损伤后肺血管内皮细胞的影响。用21只犬随机分为3组，烟雾吸入后，吸氧组（n=8）单纯吸氧（FiO2，0．45）；NO治疗组（n=9）吸氧（FiO2，0．45）＋0．0045％（45PPm）NO，连续监测12小时动脉血ACE活性变化；正常组（n＝4）不致伤，用于建立组织学对照。动脉血数据行多个样本均数间方差分析，支气管肺泡灌洗液（BALF）和肺组织ACE活性行两样本均数t检验。结果治疗组血浆ACE活性比对照组降低（P＜0．05）；BALF和肺组织中，治疗组ACE活性也明显低于对照组（P＜0．01）。吸入NO对犬烟雾吸入性损伤肺毛细血管内皮细胞有一定减轻损害作用。     

纳洛酮对肠缺血再灌流大鼠氧自由基的影响

目的探讨纳洛酮是否具有对抗肠缺血再灌流大鼠体内氧自由基的作用。方法选择成年雄性SD大鼠32只，随机分为假手术、肠缺血再灌流（I／R）及分别用生理盐水和纳洛酮干预后的肠I／R四组，分别测各组血浆及肺组织的丙二醛（MDA）含量、超氧化物歧化酶（SOD）活力。结果用纳洛酮干预后的肠I／R组大鼠MDA含量及SOD活力显著不同干I／R及I／R＋NS二组，而与假手术组相当。结论纳洛酮具有对抗肠I／R时氧自由基的作用，从而保护了肺组织免遭自由基的破坏。     

百草枯致大鼠肺损伤时内源性CO和NO的变化

目的：探讨内源性CO和NO在大鼠百草枯（PQ）中毒性急性肺损伤中的作用。方法：肺组织常规HE染色和取血测定血浆丙二醛（MDA）含量来评价肺组织损伤情况；检测血浆中肿瘤坏死因子（TNF-α）水平。检测肺组织中CO和NO含量和诱导型一氧化氮合酶（iNOS）活性。Western B10t方法测定HO-1和iNOS表达的变化。结果：PQ中毒后大鼠肺组织损伤明显加重，血浆MDA含量及TNF-α水平明显升高，应用正铁血红素（Hm）后血中CO含量明显升高，iNOS活性和N0水平则降低。结论：大鼠百草枯中毒性急性肺损伤时内源性CO和N0产生增加，在应用CO的供体氯血红素后CO升高更为明显，而NO产生降低，在一定程度上减轻了百草枯所致的大鼠急性肺损伤。     

川芎生物碱对大鼠血清中SOD活性、NO、NOS、MDA含量的影响

目的 研究川芎生物碱对局灶性脑缺血再灌注(I/R)大鼠血清中一氧化氮(NO)、一氧化氮合酶(NOS)、超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量的影响.方法 取大鼠50只,随机分成5组,每组10只.即假手术组,I/R模型组,川芎碱低、中、高剂量治疗组.采用线栓法建立大鼠局造性脑I/R病理损伤模型[1].用黄嘌呤氧化酶法测定血浆中SOD活性;用硫代巴比妥酸显色法测定血浆中MDA含量;用NOS试剂盒测定NOS活性;硝酸还原酶法测定血清中NO含量.结果 I/R组与假手术组相比,血清中的SOD活性降低,MDA含量增加(P＜0.01),川芎碱低、中、高剂量治疗组与I/R组相比,血清中的SOD活性均升高,MDA含量均降低(P＜0.05).I/R组与假手术组相比,血清中NO含量升高,NOS活性增强(P＜0.01),川芎碱低、中、高剂量治疗组与IYR组比,NO含量均显著降低(P＜0.01).结论 川芎生物碱对脑I/R引发的自由基损伤有保护作用,从而减轻脑L/R后脑绢织的损害.     

法舒地尔对大鼠离体心脏缺血/再灌注损伤的保护作用

目的观察盐酸法舒地尔对大鼠离体心脏缺血/再灌注（I/R）损伤是否有保护作用。方法SD大鼠19只,随机分为3组:I/R组、I/R+F组和对照组。用改良的Langendorff灌流装置,用K-H液行主动脉逆行灌流,建立大鼠离体心脏I/R损伤实验模型。I/R组预灌流20 min,停灌45 min,再灌30 min;I/R+F组于再灌注时在灌流液中加入盐酸法舒地尔注射液（10 mg/kg）;对照组连续灌流95 min。连续记录左心室收缩功能曲线,收集冠脉流出液,检测冠脉流出液中乳酸脱氢酶（LDH）、肌酸激酶（CK）、肌红蛋白（Mb）漏出量以及心肌细胞内钙、心肌组织一氧化氮（NO）含量和髓过氧化物酶（MPO）活力。结果心肌缺血使冠脉流出量减少,LDH、CK、Mb增加,再灌注后冠脉流出量进一步减少,LDH、CK、Mb进一步增加,同时增加细胞内钙,增加MPO活力,减少NO生成。盐酸法舒地尔逆转再灌注后冠脉流出量减少和LDH、CK和Mb漏出增加,降低细胞内钙、MPO活力,逆转NO生成减少。I/R使左室发展峰压平均值、平均±dp/dtmax均下降,盐酸法舒地尔对左室发展峰压的改变无明显影响,但改善±dp/dtmax降低。结论盐酸法舒地尔对心肌I/R损伤有保护作用,增强I/R引起的"无复流"现象和心肌收缩能力降低的恢复,此作用与逆转NO生成减少、MPO活性增高和细胞内钙超载等因素有关。     

肺组织细胞凋亡与血清细胞因子变化的关系

目的 探讨大鼠肾缺血再灌注后肺组织细胞凋亡及血清细胞因子的的变化,分析其在肾缺血再灌注后肺损伤发病机制中的作用.方法 用无损伤动脉夹钳夹大鼠双侧肾蒂45 min制成肾缺血再灌注损伤模型.观察缺血再灌注后2 h、6 h、12 h、24 h、72 h血清白介素1β(IL-1β)和一氧化氮(NO)的浓度,病理切片观察肺组织病...     

肺缺血再灌注损伤中氧化应激与Fas/FasL系统的关系

目的探讨肺缺血再灌注损伤中氧化应激与Fas/FasL系统的关系。方法采用在体兔单侧肺缺血再灌注损伤模型,日本大耳白兔40只,随机分为对照组,缺血再灌注1h、3h和5h组,每组10只。对比观察各组血浆超氧化物歧化酶活性、丙二醛含量和一氧化氮水平,以及肺组织细胞凋亡指数及Fas/FasL mRNA定位表达。结果缺血再灌注组肺组织凋亡指数明显高于对照组(P<0.01);再灌注后Fas、FasL mRNA在肺血管内皮细胞、肺泡上皮细胞及支气管上皮细胞等呈阳性表达,明显强于对照组(P<0.01);丙二醛含量随再灌注时间延长逐渐增加(P<0.01),而超氧化物歧化酶活性与一氧化氮则随再灌注时间延长有所降低(P<0.01)。结论肺缺血再灌注损伤期间,氧化应激参与Fas/FasL系统的激活。     

Beneficial effects of supplemental nitric oxide donor given during reperfusion period in reperfusion-induced lung injury

BACKGROUND: Reperfusion injury is a perplexing cause of early graft failure after lung transplantation and today we know that reperfusion may be more harmful to tissues than the preceding ischemia. We hypothesized that administration of the nitric oxide donor nitroglycerin (NTG) during flush perfusion and reperfusion periods would ameliorate reperfusion-induced lung injury. METHODS: Using an IN SITU normothermic ischemic lung rabbit model, three groups were studied (n = 7/group): (1) NTG given during flush perfusion (ischemia group); (2) NTG given in the flush perfusion and the reperfusion period (reperfusion group); and (3) no NTG (control group). All groups were flushed with low potassium dextran glucose solution. Blood gas analysis, tissue nitrite (nitric oxide metabolite) level analysis, bronchoalveolar lavage (BAL) fluid examination and morphological examinations were performed. RESULTS: Compared with the ischemia group, the reperfusion group had significantly improved arterial oxygenation (318 +/- 31.4 mmHg vs. 180 +/- 14.7 mmHg, P < 0.05), decreased BAL fluid neutrophil percentage (21 +/- 1.9 % vs. 30 +/- 5.6 %, P < 0.05), increased tissue nitrite level (32.55 +/- 4.12 nmol/g vs. 27.81 +/- 1.05 nmol/g, P < 0.05), and decreased tissue histopathological lesion scores (0.42 +/- 0.53 vs. 1.14 +/- 0.37, P < 0.05). CONCLUSIONS: This study suggests that nitric oxide donors supplemented during flush perfusion and reperfusion have more beneficial effects on lung functions against reperfusion injury than any other treatment modalities during IN SITU normothermic ischemic lung model.     

Inhibition of Inducible Nitric Oxide Synthase Prevents Hepatic, but Not Pulmonary, Injury Following Ischemia-Reperfusion of Rat Liver

The aim of this study was to investigate the contribution of inducible nitric oxide synthase (iNOS)-derived nitric oxide on the liver and lung injury following hepatic ischemia-reperfusion (I/R) using a novel and potent iNOS inhibitor, ONO-1714. Rats were subjected to 90 min of partial hepatic ischemia followed by 3, 6, 12, and 24 hr of reperfusion. Expression of iNOS mRNA peaked at 3 hr of reperfusion in the liver and lung. Plasma nitric oxide levels were increased fourfold at 24 hr of reperfusion and plasma ALT was increased, reaching a peak at 12 hr of reperfusion; both were significantly inhibited by ONO-1714. Histological examination revealed extensive liver damage, whereas this was not seen in the ONO-1714 group. Lung injury was not significantly changed in groups with versus without ONO-1714. Nitrotyrosine expression was seen in regions similar to those of the histological injuries of the liver, while this staining was absent in the ONO-1714 group. These data show that generation of peroxynitrite could be involved in the pathogenesis of liver injury but not lung injury after hepatic I/R. Inhibition of iNOS could be applied for attenuation of liver injury following hepatic I/R.     

Differential expression of pulmonary nitric oxide synthase isoforms after intestinal ischemia-reperfusion

BACKGROUND/AIMS: Nitric oxide has been implicated in both attenuating and aggravating ischemia-reperfusion injury in most organs. This study aimed to investigate the role of nitric oxide produced by the two principal isoforms of nitric oxide synthase in the lung during post-ischemic reperfusion of the intestine. METHODOLOGY: Rats were randomized into four groups of 6 animals: Group A: laparotomy and superior mesenteric artery dissection without occlusion and maintenance for 2 h (control group at 2 h). Group B: laparatomy and superior mesenteric artery occlusion for 30 min and reperfusion of the intestine for 2 h (ischemia-reperfusion group at 2 h). Group C: control animals at 6 h. Group D: ischemia-reperfusion animals at 6 h. Arterial blood pressure was monitored throughout the procedure. Animals were euthanazed at the end of the experiment, and lungs were harvested for histological assessment of injury and for immunohistochemical examination of nitric oxide synthase isoforms and nitrotyrosine. RESULTS: In all animals subjected to intestinal ischemia a period of systemic hypotension occurred immediately upon reperfusion. Histological evidence of lung injury was limited to those animals subjected to an intestinal reperfusion insult. Compared to control animals, pulmonary endothelial nitric oxide synthase expression was diminished at 2 h (p = 0.002), while expression of inducible nitric oxide synthase (p = 0.002) and nitrotyrosine (p = 0.02) was increased at 6 h. CONCLUSIONS: Following intestinal ischemia-reperfusion, early pulmonary damage is associated with decreased endothelial nitric oxide synthase expression in the lung. Expression of inducible nitric oxide synthase occurs during the later stages of reperfusion; this leads to overproduction of nitric oxide with consequent nitrosylation of protein tyrosine residues and thus aggravated pulmonary injury.     

心肌缺血/再灌注损伤后的肺组织损伤

目的初步探讨心肌缺血／再灌注损伤对肺组织损伤的可能机制。方法选取雄性成年SD大鼠（4～6月龄）,体重130～160g,建立成年大鼠缺血／再灌注模型。运用CK和MPO试剂盒检测肌酸激酶（CK）和髓过氧化物酶（MPO）的含量,运用双抗体夹心ABC—ELISA法检测细胞间黏附分子-1（ICAM-1）的含量。结果与伪手术组相比,缺血／再灌注大鼠的AN／AAR比值明显增高（P〈0．05）,CK在心肌缺血／再灌注大鼠血清中的含量明显升高（P〈0．05）,MPO与ICAM-1在心肌缺血／再灌注组大鼠血清和肺组织中含量明显升高（P〈0．05）。结论大鼠心肌缺血再灌注损伤后肺组织受到一定的损伤,可能与体循环中炎性介质的作用及肺组织的炎性应激有关。     

Endogenous nitric oxide synthesis and vascular leakage in ischemic-reperfused rabbit lungs

Pulmonary edema formation resulting from loss of capillary barrier properties is a prominent finding in lung ischemia/reperfusion (I/R) injury. The role of endogenous nitric oxide (NO) in this process is unresolved. We exposed buffer-perfused rabbit lungs to warm I/R and measured air space NO liberation and intravascular accumulation of NO degradation products. In lungs undergoing 210 min of ischemia with normoxic ventilation, with maintenance of positive intravascular pressure to avoid vascular collapse, NO synthesis was moderately reduced during ischemia but was fully restored upon reperfusion, and a moderate leakage response occurred during reperfusion. Pretreatment with the NO synthase inhibitor N(G)-monomethyl-L-arginine (L-NMMA) suppressed NO synthesis but did not affect the leakage. During ischemia with anoxic ventilation, NO synthesis was fully abrogated, but again promptly reappeared upon reperfusion and entrance of oxygen into the system. It was with this protocol that the most severe vascular leakage was encountered, which was markedly reduced in the presence of L-NMMA or superoxide dismutase. We conclude that endogenous NO does not play a major role in the induction or mitigation of I/R injury under conditions of normoxic ischemia, but that return of endogenous NO synthesis upon reperfusion after anoxic ischemia contributes substantially to the triggering of vascular leakage, possibly via interaction with superoxide.     

川芎嗪对老龄鼠再灌注肾损伤中一氧化氮的作用研究

目的 观察川芎嗪对老龄鼠肾缺血再主中一氧化氮合酶（ＮＯＳ）和一氧化氮（ＮＯ）的影响及对肾脏的保护作用。方法 制做老龄鼠肾缺血再灌注模型,分为用川芎嗪组和未用川芎嗪组,检测缺血６０ｍｉｎ,再灌注１５ｍｉｎ和２４ｈ的肾组织ＮＯＳ、ＮＯ及丙二醛（ＭＤＡ）浓度。结果 缺血再灌注后肾组织中ＮＯＳ明显升高（Ｐ〈０．０１）,ＮＯ明显升高（Ｐ〈０．０１）,ＭＤＡ明显升高（Ｐ〈０．０１）,与此结果相比,用川芎嗪组Ｎ     

Complement activation is a secondary rather than a causative factor in rabbit pulmonary artery ischemia/reperfusion injury

We have previously demonstrated that reperfusion of a rabbit lung in vivo after 24 h of unilateral pulmonary artery occlusion results in edema, transient leukopenia, and intravascular leukocyte aggregation. We hypothesized that complement was activated by reperfusion and that this in turn contributed to lung injury. In the preliminary phase of the study, we found that ischemia followed by reperfusion resulted in a drop in C3 to 15 +/- 10% (mean +/- SEM) of the prereperfusion value as compared with no change in a group of control animals that had undergone an identical thoracotomy but without pulmonary artery occlusion and reperfusion (p less than 0.05). We then studied three groups of animals to determine if complement depletion with cobra venom factor (CVF) prior to ischemia and reperfusion would prevent the injury. Rabbits treated with CVF but without occlusion and reperfusion did not develop significant lung edema, with left and right lung wet/dry ratios of 5.32 +/- 0.11 and 5.26 +/- 0.12, respectively. For rabbits that were not treated with CVF but underwent ischemia and reperfusion, the comparable numbers were 6.15 +/- 0.36 and 5.19 +/- 0.32 (p less than 0.05 for right versus left). For CVF-treated rabbits that underwent ischemia and reperfusion, the right/left difference persisted (6.77 +/- 0.48 versus 5.35 +/- 0.14, p less than 0.01). Immunocytochemistry documented C3 deposition in non-CVF rabbits that underwent ischemia and reperfusion but not in CVF-treated rabbits. We conclude that ischemia/reperfusion of the lung results in complement activation, but it is not a complement-dependent injury.     

Nitrite confers protection against myocardial infarction: role of xanthine oxidoreductase, NADPH oxidase and K(ATP) channels

Reduction of nitrite to nitric oxide during ischemia protects the heart against injury from ischemia/reperfusion. However the optimal dose of nitrite and the mechanisms underlying nitrite-induced cardioprotection are not known. We determined the ability of nitrite and nitrate to confer protection against myocardial infarction in two rat models of ischemia/reperfusion injury and the role of xanthine oxidoreductase, NADPH oxidase, nitric oxide synthase and K(ATP) channels in mediating nitrite-induced cardioprotection. In vivo and in vitro rat models of myocardial ischemia/reperfusion injury were used to cause infarction. Hearts (n=6/group) were treated with nitrite or nitrate for 15 min prior to 30 min regional ischemia and 180 min reperfusion. Xanthine oxidoreductase activity was measured after 15 min aerobic perfusion and 30 min ischemia. Nitrite reduced myocardial necrosis and decline in ventricular function following ischemia/reperfusion in the intact and isolated rat heart in a dose- or concentration-dependent manner with an optimal dose of 4 mg/kg in vivo and concentration of 10 microM in vitro. Nitrate had no effect on protection. Reduction in infarction by nitrite was abolished by the inhibition of flavoprotein reductases and the molybdenum site of xanthine oxidoreductase and was associated with an increase in activity of xanthine dehydrogenase and xanthine oxidase during ischemia. Inhibition of nitric oxide synthase had no effect on nitrite-induced cardioprotection. Inhibition of NADPH oxidase and K(ATP) channels abolished nitrite-induced cardioprotection. Nitrite but not nitrate protects against infarction by a mechanism involving xanthine oxidoreductase, NADPH oxidase and K(ATP) channels.