Rat liver ischemia and reperfusion injury in UW, HTK and Celsior

Objective To study the changes of purine nucleoside phosphorylase （PNP） and rat liver exogenous hyaluronic acid （HA） absorption after cold storage and normothermic reperfusion in University of Wisconsin （UW）, Celsior and histidine-tryptopan-ketoglutarate （HTK） solutions during ischemia and reperfusion.     

Endoxin-mediated myocardial ischemia reperfusion injury in rats in vitro

Endoxin-mediated myocardial ischemia reperfusion injury in rats in vitro@柯永胜$Department of Cardiology Yijishan Hospital,Wannan Medical College!Wuhu,China @汪和贵$Department of Cardiology Yijishan Hospital,Wannan Medical College!Wuhu,China @王德国     

Ischemic preconditioning in immature hearts： mechanism and compatibility with cardioplegia

Objective To investigate (1) whether ischemic preconditioning (IPC) could protect immature rabbit hearts against ischemia-reperfusion injury and (2) the role of K(ATP) channel in the mechanism of myocardial protection. Since cardioplegia is a traditional and effective cardioprotective measure in clinic, our study is also designed to probe the compatibility between IPC and cardioplegia. Methods New Zealand rabbits aged 14-21 days weighing 220-280 g were used. The animals were anesthetized and heparinized. The chest was opened and the heart was quickly removed for connection of the aorta via Langendorff’s method within 30 s after excision. All hearts were perfused with Krebs-Henseleit buffer balanced with gas mixture (O［２］∶CO(2)=95%∶5%) at 60 cm H［2O］ (perfusion pressure). IPC consisted of 5 min global ischemia plus 10 min reperfusion. Glibenclamide was used as the K(ATP) channel blocker at a concentration of 10 μmol/L before IPC. Cardiac arrest was induced with 4℃ St. Thomas cardioplegic solution, at which point the heart was made globally ischemic by withholding perfusion for 45 min followed by 40 min reperfusion. Thirty immature rabbit hearts were randomly divided into four groups: CON (n=9) was subjected to ischemia-reperfusion only; IPC (n=9) underwent IPC and ischemia-reperfusion; Gli (n=6) was given glibenclamide and ischemia-reperfusion; and Gli+IPC (n=6) underwent glibenclamide, IPC and ischemia-reperfusion. Coronary flow (CF), HR, left ventricle developed pressure (LVDP), and ±dp/dt(max) were monitored at equilibration (baseline value) and 5, 10, 20, 30 and 40 min after reperfusion. The values resulting from reperfusion were expressed as a percentage of their baseline values. Arrhythmia quantification, myocardial enzyme in the coronary effluent and myocardial energy metabolism were also determined. Results The recovery of CF, HR, LVDP and ±dp/dt(max) in preconditioned hearts was best among the four groups. The incidence of arrhythmia was low and less CK-MB leaked out in the IPC group. Myocardial ATP content was better preserved by IPC. Pretreatment with glibenclamide completely abolished the myocardial protection provided by IPC, but did not affect ischemia-reperfusion injury. Conclusions While applying cardioplegia, IPC provides significant cardioprotective effects. Activation of K(ATP) channels is involved in the mechanism of IPC-produced cardioprotection.     

Involvement of Apoptosis in 3-nitropropionic Acid-induced Ischemicl Tolerance to Transient Focal Cerebral Ischemia in Rats

Preconditioningofbraintissueswithsub lethalstressesorstimulicanresultinresistancetosubse quentlethalischemiceventsinaresponsecalledis chemictolerance .Recently ,severalstudieshaveshownthatasinglesystemicdoseof 2 0mg/kg 3 NPAcausednohistopathologicalabnorm…     

Cardioprotective effects of selective Na^＋/H^＋ exchanger inhibitor HOE642 against ischemia/reperfusion injury in immature hearts

Objective To compare the cardioprotective effect of HOE642, a highly selective Na^＋/H^＋ exchanger isoform-1 （NHE1） inhibitor, administered at different phase of ischemia/reperfusion in immature hearts： pre-ischemia, during ischemia and reperfusion.     

Functional Characteristics and Molecular Identification of Swelling-activated Chloride Conductance in Adult Rabbit Heart Ventricles

Outwardly rectifying swelling-activated chloride conductance （ICl, Swell） in rabbit heart plays a critical role in cardioprotection following ischemic preconditioning （IP）. But the functional characterization and molecular basis of this chloride conductance in rabbit heart ventricular myocytes is not clear. Candidate chloride channel clones （e.g. ClC-2, ClC-3, ClC-4 and ClC-5） were determined using RT-PCR and Western blot analysis.Whole cell ICl,Swell was recorded from isolated rabbit ventricular myocytes using patch clamp techniques during hypo-osmotic stress. The inhibitory effects of 4,4＇ isothiocyanato-2,2-disulfonic acid （DIDS）, 5-nitro-2（3-phenylroylamino） benzoic acid （NPPB） and indanyloxyacetic acid 94 （LAA-94） on ICl,Swell were examined. The expected size of PCR products for ClC-2, ClC-3 and ClC-4 but not for ClC-5 was obtained. ClC-2 and ClC-3 expression was confirmed by automated fluorescent DNA sequencing. RT-PCR and Western blot showed that ClC-4 was expressed in abundance and ClC-2 was expressed at somewhat lower levels. The biological and pharmacological properties of ICl,Swell, including outward rectification, activation due to cell volume change, sensitivity to DIDS, LAA-94 and NPPB were identical to those known properties of ICl,Swell in exogenously expressed systems and other mammals hearts. It was concluded that ClC-3 or ClC-4 might be responsible for the outwardly rectifying part of ICl,Wwell and may be the molecular targets of cardioprotection associated with ischemic preconditioning or hypo-osmotic shock.     

The effects of ischemia-reperfusion injury and hepatic artery ischemia on CD14 expression in canine auto-transplantation livers

Objective: To study the effect of ischemia-reperfusion injury(IRI) and hepatic artery ischemia(HAI) on CD14 expression in canine auto-transplantation livers. Methods:Liver orthotopic auto-transplantation models were applied with 30 healthy male Xi’an canines which were randomly divided into a control group, simultaneous reperfusion(SR) group and HAI group. CD14 protein expression, Malonaldehyde (MDA) Contents in hepatic tissues and ALT values in serum were detected, and the pathological changes of hepatic tissues was investigated under the light microscopy. Results:The level of CD14 protein expression in SR and HAI group tended to be time-dependent and both higher than controls with statistical significance(P < 0.01); The peak values of these two groups both occurred at 4 h, but the level in HAI group (11.94± 0.43) was evidently higher than that in SR group(3.04± 0.34). MDA contents in liver tissue, ALT values in serum and pathological changes showed the same changing tendency as CD14 expression. Conclusion:① Up-regula- tion of CD14 expression may be the receptor-mechanism of Kupffer cells(KCs) activation in liver transplantation. ② HAI can up- regulate CD14 expression after portal vein reperfusion, improve the activity of KCs further more, increase OFRs production and coop- erate with portal reperfusion, and finally aggravate the grafts injury.     

Activation and subcellular distribution of ERK1/2 following cerebral ischemia/reperfusion in rat hippocampus

Objective： To investigate the activation （phosphorylation） and subcellular localization of extracellular signal-regulated kinase （ERK1/2）, as well as the possible mechanism, following cerebral ischemia and ischemia/reperfusion in rat hippocampus. Methods： Transient brain ischemia was induced by the four-vessel occlusion method in Sprague-Dawley rats. Western blot analysis. Results： During cerebral ischemia without reperfusion ERK1/2 activation immediately increased with a peak at 5 min and then decreased in the cytosol fraction, which was paralleled by the increase of ERK1/2 activation in the nucleus fraction. During reperfusion, ERK1/2 was activated with peaks occurring at 10 min in the cytosol and at 30 min in the nucleus, respectively. Under those conditions, the protein expressions had no significant change. In order to clarify the possible mechanism of ERK1/2 activation, the rats were intraperitoneally administrated with N-methyl-D-aspartate （NMDA） receptor antagonist dextromethorphan （DM）, L-type voltage-gated Ca^2＋ channel （L-VGCC） antagonist nifedipine （ND） 20 rain before ischemia, finding that DM and ND markedly prevented ERK1/2 activation of nucleus fraction induced by reperfusion, not by ischemia. Conclusion： These results suggested that the nuclear translocation mainly occurred during ischemia, while ischemia-reperfusion induced ERK1/2 activation both in the cytosol and the nucleus. Two type calcium channels contributed, at least partially, to the activation of ERK1/2.     

Gene Expression Profile of Pulmonary Tissues in Different Phases of Lung Ischemia-reperfusion Injury in Rats

In order to provide us new clues to induce some endogenous protective molecular mechanisms, the changes in gene expression profile induced by ischemia-reperfusion in pulmonary tissues of rats were investigated and the dynamic mechanism of pulmonary ischemia-reperfusion injury was elucidated. Thirty male Wistar rats were randomly divided into 6 groups： 5 ischemia-reperfusion （I/R） groups （I/R 0-h, I/R 1-h, I/R 3-h, I/R 6-h, I/R 24-h） and control group （n=5 in each）. An in situ ischemia-reperfusion lung injury rat model was established by occluded hilus of lung. The RatRef-12 Expression Beadchip （22 226 gene probes per array） was used to analyze the pattern of gene expression in all groups. The results showed that 648, 340, 711, 1279 and 641 genes were differentially expressed in I/R 0-, 1-, 3-, 6- and 24-h groups respectively. The differentially expressed genes were classified as following 7 functional categories： cytokine, adhesion molecule, growth factor and apoptosis-related factor, oxidation and antioxidation molecule, metabolic enzyme, ion channel and aquaporin, signal transduction molecule. It was suggested that gene chip technology was an effective and quick method for screening differentially expressed genes. Many differentially expressed genes with different functions interacted each other to result in pulmonary ischemia-reperfusion injury.     

Significance of Rosiglitazone Inhibiting TLR4 Expression in Partial Hepatic Ischemia/Reperfusion of Mice

The effect of rosiglitazone as the ligand of peroxisome proliferator-activated receptor γ (PPARγ) inhibiting the TLR4 expression in ischemic lobes in partial hepatic ischemia/reperfusion injury (IRI) in BABL/C mice and the action of rosiglitazone inhibiting the TLR4 receptor-mediated inherent immune response were investigated. The model of the mouse partial hepatic ische- mia/reperfusion injury was established. All the animals were randomly divided into 3 groups: rosiglitazone group, vehicle (dimethylsulphoxide, DMSO) group and sham operation group. The hepatic samples were collected when mice were sacrificed 0, 2, 4 and 6 h after reperfusion following 1 h ischemia to analyze the acute phase of hepatic IRI. The dynamic expression of TlR4 mRNA was de- tected quantitatively by real-time-PCR, and the levels of TNF-α, IL-10 and ALT in portal vein were determined in all groups. After restoration of blood supply, the expression of TLR4 mRNA in ischemic lobes was detected in 0, 2, 4 and 6 h after reperfusion following 1 h ischemia in rosiglitazone group and vehicle group. The most intensive expression of TLR4 mRNA was present at 4 h after reperfusion in ischemic lobes in vehicle group. As compared with vehicle group, the expression of TLR4 mRNA in ischemic lobes in rosiglitazone group was significantly decreased at 4 h after reper- fusion. The level of IL-10 in portal vein was markedly up-regulated in rosiglitazone group as compared with vehicle group. Contrarily, the levels of TNF-α and ALT in portal vein were markedly down-regulated in rosiglitazone group as compared with vehicle group at every time point in mouse partial hepatic IRI model. Rosiglitazone could alleviate the hepatic IRI by inhibiting TLR4 receptor-mediated inherent immune response.     

小鼠肝脏部分缺血再灌注过程中Toll样受体2的激活及意义

目的探索Toll样受体2(Toll-like receptor 2,TLR2)在小鼠肝脏部分缺血肝叶中的激活,分析TLR2的激活与肝功能损伤之间的关系.方法BALB/c小鼠复制肝脏部分缺血再灌注(缺血1h再灌注4h)损伤动物模型(I/R组),假手术对照组(SH组)同样行开腹手术但不夹闭血管.采用实时荧光定量PCR(Real-time-PCR)方法定量检测缺血肝叶中TLR2mRNA的表达变化,同时采用Western blot检测缺血肝脏组织中TLR2蛋白的表达变化,检测门静脉血浆丙氨酸氨基转移酶(pALT)水平.结果肝脏部分缺血1h再灌注4h后,I/R组与SH组小鼠缺血肝叶TLR2 mRNA的表达(△Ct值)分别为(1.06±0.91)vs(5.08±1.32)(P＜0.01),由于△Ct值越小则基因表达水平越高,说明缺血再灌注过程中缺血肝叶TLR2mRNA的表达水平增高.且I/R组小鼠缺血肝叶TLR2蛋白的表达(OD值)水平较SH组高[(433.91±25.53)vs(102.86±13.58),P＜0.01],I/R组中门静脉血清ALT水平升高[(848.33±271.37)μ/Lvs(42.39±14.75)μ/L,P＜0.01].结论TLR2在肝脏缺血再灌注过程中缺血肝叶的表达增强,且这种变化与肝功能的损伤相关.     

TLR4蛋白在小鼠肝脏部分缺血再灌注损伤中时序性表达及意义

目的通过研究Toll样受体4(Toll-like receptor-4,TLR4)蛋白在小鼠肝脏部分缺血再灌注损伤模型中的动态表达,探讨TLR4受体的激活与肝功能损伤间的关系.方法以BALB/c小鼠复制肝脏部分缺血再灌注损伤模型,采用免疫组织化学染色方法动态观察TLR4在肝脏的分布,并用HPIAS-1000图文报告系统分析结果,同时动态监测血浆谷丙转氨酶水平及门静脉血清内毒素水平.结果肝脏左中叶缺血1 h后,不同的再灌注时间,缺血肝叶内有增强的TLR4蛋白的阳性表达,以再灌注1 h的表达最为强烈,阳性细胞主要是Kupffer细胞及血管内粒单核细胞,且TLR4的动态表达与肝功能的损伤不平行.门静脉血清内毒素水平在各时间点与假手术组相比无显著差异(P＞0.05).结论在非内毒素血症下,TLR4蛋白在肝脏缺血再灌注损伤过程中有动态表达.TLR4的激活参与了肝脏缺血再灌注损伤的过程.     

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Background Restoration of blood flow to the ischemic liver lobes may paradoxically exacerbate tissue injury, which is called hepatic ischemia/reperfusion injury （IRI）. Toll-like receptor 4 （TLR4）, expressed on several liver cell types, and the nuclear factor-kappa B （NF-KB） signaling pathway are crucial to mediating hepatic inflammatory response. Because IRI is essentially a kind of profound acute inflammatory reaction evoked by many kinds of danger signals, we investigated TLR4/NF-KB signaling pathway activation in a murine model of partial hepatic IRI. Methods Wild-type mice （WT, C3H/HeN） or TLR4 mutant mice （C3H/HeJ） were subjected to 45 minutes of partial hepatic ischemia followed by 1 hour, 3 hours of reperfusion. Sham group accepted the same procedure without the obstruction of blood supply. At the end of reperfusion, the compromise of liver function and the histological change of liver sections were measured as the severity of liver injury. The level of endotoxin in the portal vein was measured by limulus assay. NF-KB activation was determined by electrophoretic mobility shift assay （EMSA）. The levels of tumor necrosis factor-a （TNF-a） and intedeukin-1β （IL-1β） in systemic blood after hepatic IRI were assessed by enzyme-linked immunosorbent assay （ELISA）. Results The compromise of liver function and the morphological injuries in mutant mice were relieved more markedly than those in WT mice after partial hepatic IRI. NF-KB activation in WT mice was stronger than that in TLR4 mutant mice, and both were stronger than those in the sham operated mice （P〈0.01）. Endotoxin in each group was undetectable. The levels of TNF-α and IL-1β in systemic blood were elevated in both strains, but lower in the sham operated group. These mediators were significantly decreased in TLR4 mutant mice compared with those in WT mice （P〈0.01）. Conclusions The TLR4/NF-KB signaling pathway may mediate hepatic IRI triggered by endogenous danger signals. Inhibition of the TLR4/NF-KB pathway may be a potential therapeutic target for attenuating ischemia/reperfusion-induced tissue damage in some clinical settings.     

过氧化物酶增殖物激活受体γ抑制肝脏缺血再灌注损伤中Toll样受体4表达的意义

目的研究肝部分缺血再灌注损伤过程中过氧化物酶增殖物激活受体γ（PPARγ）、Toll样受体4（TLR4）和IL-10相互作用的可能机制。方法制作小鼠肝脏部分缺血再灌注损伤模型。30只小鼠随机分为4组：罗格列酮组、罗格列酮＋双酚丙控二环氧甘油醚（BADGE）组、BADGE组、对照组。复灌4h取材。采用实时荧光PCR方法检测PPARhTLR4在小鼠肝脏部分缺血再灌注损伤中的表达,同时检测血清TNF、IL-10、AIT水平。结果罗格列酮组较其它三组PPARγ的表达和血清IL-10水平增高,rrLR4的表达、血清TNF-α和ALT水平较其它三组减弱（P〈0．05）,罗格列酮＋BADGE组、BADGE组及对照组间的PPARγ和TLR4表达无显著差别。结论在鼠肝脏缺血再灌注过程中,罗格列酮激活PPARγ并上调IL-10水平,抑制TLR4表达。     

还原型谷胱甘肽对大鼠肝脏缺血再灌注损伤的保护作用

目的:探讨缺血前经门静脉注射还原型谷胱甘肽(GSH)对大鼠肝脏缺血再灌注损伤的保护作用.方法:20只雄性SD大鼠随机均分为2组,生理盐水处理组(IR组)和GSH预处理组(GPC组),缺血前分别经门静脉主干注射生理盐水或GSH 3 ml/kg,15 min后阻断左、中叶肝蒂45 min,再开放肝蒂40 min,建立约70%肝脏缺血再灌注损伤模型.缺血前及再灌注末经下腔静脉穿刺抽血,测血清ALT、AST含量;取左叶肝组织,测丙二醛(MDA)含量和P-选择素表达情况.结果:缺血前2组血清ALT、AST水平、左叶肝组织MDA含量差异无统计学意义(P均＞0.05).再灌注末,GPC组血清ALT、AST水平、缺血肝组织MDA含量和P-选择素蛋白表达低于IR组(P均＜0.05).结论:缺血前经门静脉途径注射GSH可以有效减轻肝脏缺血再灌注损伤程度,该作用可能与减少血循环中自由基含量、抑制肝组织P-选择素表达有关.     

The effect of reactive oxygen species of inducing apoptosis on the hepatocacinoma in the rabbits

Objective: To study the effect of reactive oxygen species of inducing apoptosis on the heptocacinoma tissues following ischemia and reperfusion and perfusion hyperoxia liquid of hepatocarcinoma. Methods: The hepatocarcinoma animal models ware established by implantation of VX2 tumor constitution mass into the left middle lobe of liver of rabbits. The animals were subjected to 60 min clamp-induced ischemia of hepatic artery distributing in the left middle lobe followed by reperfusion atlh, Id, 3d and 7 d, respectively, and perfusion hyperoxia liquid (partial pressure of oxygen, PO2＞80 kPa) at the same time with reperfusion beginning. The concentration of MDA and NO ware tested. Apoptotic changes in the hepatocarcinoma and normal hepatic tissues were observed by means of HE staining and terminal de-oxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNED. Results: The concentration of MDA in normal hepatic tissues and hepatocarcinoma tissue increased followed ischemia and reperfusion especially for reperfusion 1 h (4. 61 ±0. 40, 3. 10±0. 23) and restored to normal level at reperfusion 7 d in normal hepatic tissues but still kept high concentration in the hepatocarcinoma tissue. Even though concentration of MDA in normal hepatic tissues is higher than that of before ischemia and reperfusion, no difference have been found after perfusion of hyperoxia liquid, and in the hepatocarcinoma tissue. the increasing of concentration of MDA was obvious after simply ischemia and reperfusion at reperfusion Id (4. 25 ± 0. 45). The concentration of NO in normal hepatic tissues increased for reperfusion 3 d and 7 d(18. 17± 0. 13, 17. 45±0. 23),while that of hepatocarcinoma tissue decreased at reperfusion 3 d(15. 95±043). After perfusion of hyperoxia liquid, the concentration of NO in normal hepatic tissues kept increasing and that decreased in the hepatocarcinoma tissues in all time point and reached the lowest level at reperfusion 1 d(14. 62±O. 45). The result demonstrated the changes of concentration of NO and MDA in the hepatocarcinoma tissues ware more obvious than that of normal hepatic tissues(P＜0. 01). Conclusion: Perfusion of hyperoxia liquid from hepatic portal vein can intensify ischemia and reperfusion injury but less so for normal hepatic tissues.     

小鼠肝脏持续低灌注模型的建立及其对热缺血再灌注损伤的耐受性

目的 建立一种稳定的小鼠肝脏持续低灌注模型,并在此基础上研究肝脏持续低灌注对小鼠肝脏热缺血再灌注损伤的影响.方法 选用6～8周龄C57BL/6小鼠建模,将门静脉缩窄至1 mL注射器针头直径,门静脉缩窄后3d、7d、14d和21 d行肝功能及肝脏组织病理学检测;选用稳定的模型小鼠行70％缺血再灌注手术,再灌注3h、24 h、48 h后行肝功能及肝脏组织病理学检测.对照组采用正常C57BL/6小鼠行缺血再灌注手术.结果 小鼠门静脉缩窄术后,丙氨酸转氨酶(ALT)和天冬氨酸转氨酶(AST)均有不同程度的升高,在7d时达到高峰[ALT:(60.8±6.2)U/L vs (25.5±2.8) U/L,P＜0.001;AST:(74.9±6.1)U/L vs (39.1±3.2) U/L,P＜0.001),同时H-E染色显示7d时肝细胞损伤最重,并且有较多炎细胞浸润;在21 d时,ALT基本恢复正常水平(P＞0.05),而AST仍高于正常水平(P=0.03).低灌注处理7d的小鼠进行缺血再灌注手术后,肝酶和组织病理学检查显示肝细胞损伤较对照组显著加重,肝酶在再灌注3h达到高峰[ALT:(8 217.0±1 111.8) U/L vs(5 597.4±1 015.3) U/L,P=0.004;AST:(8 548.2±1 155.4)U/L vs(5 765.4±956.9)U/L,P=0.003];再灌注48 h时,对照组小鼠ALT和AST均恢复正常,而经过低灌注处理的小鼠肝酶仍高于对照组[ALT:(608.8±442.9)U/L vs (47.4±20.1)U/L,P=0.008;AST:(861.8±442.8)U/L vs (70.8±68.3)U/L,P=0.008).结论 成功建立了稳定的小鼠肝脏持续低灌注模型,经持续低灌注处理后的肝脏对热缺血再灌注损伤的耐受能力显著降低,这在一定程度上能够模拟临床上心死亡器官捐献供肝的状况.