缺血预处理对大鼠移植肝脏保存再灌注损伤的保护及机制探讨

目的探讨缺血预处理 (ischemicpreconditioning ,IP)对大鼠移植肝脏保存再灌注损伤的保护作用及机理。方法采用SD大鼠原位肝移植动物模型 ,12 8只大鼠随机分成A(对照组 )、B(IP组 )、C(腺苷 ,Ado组 )、D(NO合成抑制剂 ,NAME组 )组 ,每组 32只。其中各组的半数用于观察存活率 ,另一半用于移植肝脏再灌注 2h后取血及肝脏检测。结果IP组和Ado组的 1周存活率、血清NO水平及肝组织腺苷含量分别为 88% (7/ 8)和 88% (7/ 8) ,(33 0± 6 1) μmol/l和 (2 9 1± 6 5 ) μmol/l,(7 2± 1 8) μmol/g和 (5 7± 1 3) μmol/g ,均高于对照组的 38% (3/ 8) ,(15 4± 3 0 )mol/L和 (3 6 9±0 5 4 ) μmol/g (P <0 0 5 ) ,血清ALT及TNF含量分别为 (2 87± 82 )IU/L和 (35 7± 93)IU/L ,(1 15± 0 2 3)ng/ml和 (1 14± 0 2 7)ng/ml,均低于对照组的 (5 88± 5 8)IU/L及 (1 5 9± 0 35 )ng/ml(P <0 0 5 ) ,组织的病理学改变也轻于对照组 ;NAME组的 1周存活率、血清NO及ALT含量等分别为 2 5 % (2 / 8)、(13 74± 3 11) μmol/l及 (6 34± 6 5 )IU/L ,与对照组相近 (P >0 0 5 ) ,而肝组织腺苷含量为 (5 5 6± 1 19)μmol/g ,与对照组差异有显著意义 (P <0 0 5 )。 结论IP对大鼠移植肝脏的保存再灌注损伤具有保护     

Amelioration of tumor necrosis factor release by cyclosporine in warm ischemia/reperfusion injury of the rat liver: with special reference to hepatic ultrastructure

Mechanisms by which an immunosuppressant (cyclosporine, CsA) ameliorates warm ischemic injury of the liver were studied. Female Sprague-Dawley rats were subjected to 60-min normothermic liver ischemia. Animals were assigned to one of two groups: group I, controls with vehicle treatment; group II, treatment with CsA (10 mg/kg). CsA was given orally for 4 consecutive days prior to the induction of hepatic ischemia. In addition to a survival study, plasma levels of endotoxin, serum activity of tumor necrosis factor-α (TNF), and serum levels of aminotransferases were measured in blood samples collected from the suprahepatic vena cava, and hepatic ultrastructural alterations were examined under an electron microscope. The 7-day survival rate was significantly higher in the CsA-treated animals. In the control group, serum TNF levels were elevated following reperfusion and peaked at 3 h. When the values at 3 h post reflow were compared, the animals given CsA had significantly lower levels of TNF (170.0 ± 30.5 pg/ml for group I, 67.6 ± 13.7 for group II, mean ± SEM; P < 0.05). The sinusoidal lining cells and hepatocytes were drastically destroyed at 6 h post reflow in the control group, although the degree of injury at 1–3 h was less severe. On the other hand, the endothelium and parenchymal liver cells in the CsA-treated group were well preserved at 6 h in comparison with those in the control group. Our data suggest that modulation of TNF production is one of the mechanisms through which CsA prevents the exacerbation of ischemia/reperfusion injury of the liver. Received for publication on Aug. 12, 1998; accepted on Feb. 2, 1999     

Oxymatrine attenuates intestinal ischemia/reperfusion injury in rats

PURPOSE: Intestinal ischemia/reperfusion (I/R) is a common and serious clinical condition. The anti-inflammatory and anti-apoptotic properties of oxymatrine, the extract from a traditional Chinese herb, Sophora flavescens Ait, have been shown to protect the liver from I/R injury and attenuate colitis. The objective of this study was to investigate if oxymatrine could attenuate intestinal I/R injury induced in rats. METHODS: The experimental design consisted of three groups of 24 Wistar rats each: a sham-operation group (control group), a group subjected to intestinal I/R and then given saline (saline group), and a group subjected to intestinal I/R and then given oxymatrine (oxymatrine group). Intestinal I/R was induced by occluding the superior mesenteric artery for 45 min. Six rats from each group were killed at selected time points, and blood and intestinal samples were collected. RESULTS: Morphological alteration, reduction of gamma-glutamyl transpeptidase (gamma-GGT) activity, and increased cell apoptosis confirmed intestinal I/R injury. The oxymatrine group had a significantly lower histological score and apoptosis index than the saline group, demonstrating that the preadministration of oxymatrine attenuated gut damage. Moreover, oxymatrine inhibited the production of lipid peroxides (LPO), decreased the serum levels of tumor necrosis factor (TNF)-alpha, and downregulated expression of phosphorylated p38 mitogen-activated protein kinase, Fas, and FasL, which had been elevated by I/R. CONCLUSIONS: These results provide further evidence of the anti-inflammatory and anti-apoptotic activities of oxymatrine, which may become a potent drug for protecting the intestines against I/R injury.     

肝脏缺血/再灌注后线粒体损伤与促凋亡蛋白的释放

肝脏缺血／再灌注（I／R）损伤是临床上较为常见的组织器官损伤之一，细胞凋亡在肝脏I／R损伤中起到了重要作用。近年来的研究发现，I／R导致线粒体通透性改变，由此引起线粒体膜电位的降低和促凋亡蛋白的释放等一系列变化，在细胞凋亡中发挥关键作用。     

冷保存再灌注损伤对大鼠移植肝术后早期胆盐分泌的影响

目的 探讨大鼠移植肝脏经历冷保存再灌注损伤（CPRI）后胆盐谱的变化规律。方法 建立专门用于胆汁胆盐检测的柱前衍生反相高效液相色谱法（RP—HPLC）。大鼠被随机分为对照组（A组,n=6）、供肝冷保存1h组（B组,n=6）和供肝冷保存12h组（C组,n=6）。对各组大鼠术后14d的胆汁标本进行RP—HPLC分析。结果 共检出11种胆盐。CPRI可以显著影响大鼠移植肝胆盐的组成,主要表现为疏水性的牛磺胆酸和牛磺脱氧胆酸比重的持续增加以及亲水性的牛磺猪脱氧胆酸和牛磺熊脱氧胆酸比重的一过性升高。术后1～4d,胆盐疏水指数（HI）无显著变化;从术后5d开始,胆盐HI显著上升,术后7～10d达到高峰。且供肝冷保存时间越长,HI升高越显著。结论 经历CPRI后,移植肝胆汁疏水性胆盐比重的上升可能是导致胆汁细胞毒性增加的主要原因之一。     

二氮嗪预处理对肝硬化大鼠肝脏的保护作用

目的探讨采用线粒体ATP敏感性钾通道(mitoKATP通道)选择性开放剂二氮嗪(DE)进行预处理能否模拟缺血预处理(IP)对硬化肝脏缺血再灌注损伤的保护作用及其可能的作用机制。方法雄性肝硬化SD大鼠随机分为5组(每组8只)。IP组以肝缺血5 min作预处理;DE组以静脉注射DE作为预处理;DE 5-HD组是在DE组基础上再予静注mitoKATP通道选择性阻滞剂5-hydroxydecanoate(5-HD)进行预处理;对照组(C组)以静注等量生理盐水作为预处理;上述4组均在预处理后行肝缺血45 min再灌注60 min;缺血方式均为70%肝脏热缺血。假手术组(S组)仅行开腹,不作任何其他处理。完成预定实验操作后分别取血用于血清谷丙转氨酶(ALT)与乳酸脱氢酶(LDH)检测,切取肝组织用于测定ATP酶活力、湿重/干重(W/D)的测定及观察显微、超微结构变化。结果C组ALT,LDH,ATP酶及W/D的水平明显高于S组(P<0.01),肝脏的显微及超微结构损伤明显;IP组与DE组的各项肝组织损伤指标均明显好于C组,ATP酶活性低于C组(P<0.05及P<0.01);而DE 5-HD组的肝损伤指标均差于DE组,ATP酶活性高于DE组(P<0.05及P<0.01)。结论使用DE进行药物预处理能够模拟出IP效应,对肝硬化大鼠肝脏I/R损伤具有保护作用,其作用可能与下调肝组织ATP酶活性,减少ATP大量分解,使肝组织ATP含量升高,改善肝能量代谢,增加能量储备;改善肝组织微循环,减轻肝脏水肿有关。     

核因子-κB/I-κB传导通路在肝脏缺血再灌注损伤中的作用

目的 探讨核因子(NF)—κB／Ⅰ—κB传导通路在肝脏缺血再灌注损伤中的作用。方法 采用阻断大鼠部分肝血供的缺血再灌注损伤模型，左半肝缺血90min，再灌注分0、1、2、4h等时点。用凝胶滞留电泳方法测定NF—κB的结合活性；应用逆转录—聚合酶链反应(RT—PCR)测定肝组织中肿瘤坏死因子—α(TNF—α)、细胞间粘附因子—1(ICAM—1)mRNA的表达量。结果 肝脏缺血再灌注损伤时NF—κB与其特异性调控序列的结合活性增高且具有时相性。再灌注1～2h NF—κB结合活性增高，4h后开始降低。肝组织中TNF—α、ICAM—1 mRNA表达在再灌注2h后升高。讨论 肝脏缺血再灌注损伤时，NF—κB激活并进入细胞核内，与一些炎症因子基因启动子区特异序列结合，上调TNF—α、ICAM—1 mRNA表达，从而引起肝脏缺血再灌注损伤。     

含饱和氢气肾保存液对大鼠肾脏冷缺血再灌注损伤的影响

目的 评价含饱和氢气肾保存液对大鼠肾脏冷缺血再灌注损伤的影响.方法 健康雄性Wistar大鼠24只,周龄8～10周,体重200～ 250 g,采用随机数字表法,将其随机分为3组(n=8):对照组(H1组)大鼠仅切除右肾;普通肾保存液组(H2组)大鼠采用冷缺血再灌注模型,用4℃普通HC-A肾保存液对左肾行冷灌注和冷保存;含饱和氢气肾保存液组(H3组)大鼠操作同H2组,灌注液及保存液换用自制的4℃含饱和氢气HC-A肾保存液.于再灌注24 h时抽取下腔静脉血样,测定血清BUN、Cr、TNF-α和IL-6浓度;切取左肾,测定肾组织MDA和8-羟基脱氧鸟苷(8-OHdG)含量,光镜下观察肾组织病理学结果.结果 与H1组相比,H2组和H3组大鼠血清BUN、Cr、TNF-α和IL-6浓度及肾组织MDA和8-OHdG含量均升高(P＜ 0.05);与H2组相比,H3组血清BUN、Cr、TNF-α和IL-6浓度及肾组织MDA和8-OHdG的含量均降低(P＜0.05).H1组肾组织形态结构未见明显异常,H2组肾小管损伤明显,H3组肾小管损伤较H2组减轻.结论 含饱和氢气肾保存液可明显减轻大鼠肾脏冷缺血再灌注损伤.     

供肝保存与功能维护助力肝移植发展

肝移植作为终末期肝病的有效治疗方法已在世界范围内广泛开展,并逐渐取得普遍认可。随着肝移植手术技术趋于成熟,术后并发症发生率逐步降低,受者的短期和长期预后持续改善。然而,器官的供应与需求之间一直存在着巨大鸿沟,是限制肝移植手术开展的重要原因。国内肝移植手术量逐年上升,供肝短缺问题日益突出,边缘供肝越来越多地应用于临床。近年来,供者器官的选择标准、器官的保存及功能维护技术不断完善。本文将从供肝保存、功能维护两方面,结合二者近年来的技术发展和研究成果,评述不同技术的应用情况和发展趋势,为进一步提高移植物和受者生存率,促进我国肝移植的发展提供参考。     

灯盏花素预处理供肝减轻大鼠肝移植后早期缺血再灌注损伤

目的 研究应用灯盏花素对供肝进行预处理,减轻大鼠肝移植术后早期缺血再灌注损伤的作用.方法 以SD大鼠作为肝移植供、受者,采用随机数字表法将受鼠分为4组.A组和C组供肝未经灯盏花素预处理,B组和D组供肝经含20 mg/L灯盏花素的UW液预处理;A组和B组供肝冷缺血时间为30～40 min,C组和D组为12 h.术后检测各组受鼠的凝血功能、肝功能、血清血栓调节蛋白(TM)含量、凋亡蛋白酶-3 (Caspase-3)活性及核因子-kB(NF-kB)相对表达量,观察各组移植肝组织病理学变化和肝细胞凋亡情况.结果 术后3d,C组与D组受鼠死亡率分别为40.0％(8/20)和29.4％(5/17),差异无统计学意义(P＞0.05);术后4组间凝血功能无明显变化(P＞0.05).与C组比较,术后早期D组肝功能、肝组织病理学改变及肝细胞凋亡均明显改善(P＜0.01),血清TM含量、Caspase-3活性及NF-kB表达量均明显降低(P＜0.01).术后A组和B组的缺血再灌注损伤明显较轻,两组间上述指标的差异均无统计学意义(P＞0.05).结论 应用灯盏花素对供肝进行预处理,能够减轻大鼠肝移植术后由冷保存时间较长引起的缺血再灌注损伤,其机制可能与抑制凋亡相关的信号通路和减轻肝脏微循环内皮细胞损伤有关.     

Kupffer细胞在肝移植缺血再灌注损伤中的双重作用

Kupffer细胞足定居于肝内的巨细胞,在月十移植缺血再灌注损伤中发挥着重要的作用,门静脉恢复血流后刺激Kupffer细胞激活,释放活性氧族、多种炎性介质和细胞因子,对肝脏造成损伤.另一方面又可上调HO-1的表达,保护肝脏缺血再灌注损伤,因此,Kupffer细胞在肝移植缺血再灌注损伤中发挥着双重效应.     

血红素加氧酶-1诱导对鼠肝缺血再灌注损伤的保护作用

目的研究血红素加氧酶-1(heme oxygenase-1,HO-1)在鼠肝缺血再灌注损伤肝组织中的表达及其作用。方法建立小鼠部分肝脏热缺血再灌注损伤模型,36只清洁级Balb/C小鼠随机分为3组: 假手术组(S组)、缺血/再灌注损伤组(I/R组)、HO-1诱导剂氯化高铁血红素(hemin)预处理组(HM组)。免疫组化半定量分析肝组织HO-1蛋白的表达,检测血清AST和ALT,肝组织丙二醛(MDA)含量及超氧化物歧化酶(SOD)活性,并观察肝组织的病理变化。结果与S组比较,I/R组HO-1蛋白表达显著增强,hemin预处理后,HO-1蛋白表达较I/R组增高(P<0．01)。I/R组AST,ALT活性和MDA的含量显著高于S组,而HM组均显著低于I/R组(P<0．01);I/R组SOD活性下降,而HM组显著高于I/R组(P<0．01)。HM组病理损伤程度明显轻于I/R组。结论 HO-1在鼠肝缺血再灌注损伤肝组织中表达上调,对肝脏具有保护效应。     

Silent information regulator 1 protects the liver against ischemia–reperfusion injury: implications in steatotic liver ischemic preconditioning

Ischemia–reperfusion (IR) injury is an important problem in liver surgery especially when steatosis is present. Ischemic preconditioning (PC) is the only surgical strategy that has been applied in patients with steatotic livers undergoing warm ischemia. Silent information regulator 1 (SIRT1) is a histone deacetylase that regulates various cellular processes. This study evaluates the SIRT1 implication in PC in fatty livers. Homozygous (Ob) Zucker rats were subjected to IR and IR + PC. An additional group treated with sirtinol or EX527 (SIRT1 inhibitors) before PC was also realized. Liver injury and oxidative stress were evaluated. SIRT1 protein levels and activity, as well as other parameters involved in PC protective mechanisms (adenosine monophosphate protein kinase, eNOS, HSP70, MAP kinases, apoptosis), were also measured. We demonstrated that the protective effect of PC was due in part to SIRT1 induction, as SIRT1 inhibition resulted in increased liver injury and abolished the beneficial mechanisms of PC. In this study, we report for the first time that SIRT1 is involved in the protective mechanisms induced by hepatic PC in steatotic livers.     

Danshen protects liver grafts from ischemia/reperfusion injury in experimental liver transplantation in rats

Reperfusion injury remains one of the major problems in transplantation. Free radicals and disturbance of microcirculation are the supposed main contributors. Recent evidence shows that Danshen, a traditional Chinese drug used in vascular diseases, can scavenge radicals and improve microcirculation. This study investigates its effect on liver transplantation (LTx). Before organ recovery, female Sprague-Dawley rats (210–240 g) received intravenous Danshen or the same volume of Ringer solution as control. LTx was performed after 1 h of cold storage. Microperfusion, leukocyte-endothelium interaction and latex-bead phagocytosis were evaluated with in vivo microscopy. Survival, transaminases and histology were assessed. Immunohistology was used for TNF-α levels. anova and Fisher's exact test were employed for statistical analyses as appropriate. Survival increased from 60% in controls to 100% ( P  < 0.05). AST and LDH decreased from 3969 ± 1255 U/l and 15444 ± 5148 U/l in controls to 1236 ± 410 U/l and 5039 ± 1594 U/l, respectively ( P  < 0.05). In vivo microscopy revealed decreased leukocyte-adherence and increased blood flow velocity in sinusoidal zones after administration of Danshen ( P  < 0.05), while latex-bead phagocytosis was found in 60% of controls ( P  < 0.05). The TNF-α index decreased from 2.08 ± 0.09 in controls to 1.09 ± 0.09 ( P  < 0.05). This study clearly demonstrates hepatoprotective effects after experimental LTx, which can be explained via anti-oxidative effects, improved microcirculation and decreased Kupffer cell activation.     

血红素氧合酶-1减轻大鼠移植肝缺血再灌注损伤的作用及机制

目的 探讨血红素氧合酶-1(HO-1)减轻大鼠移植肝缺血再灌注损伤的作用及其机制.方法 选择近交系雄性SD大鼠作为肝移植的供、受者;采用单纯随机方法将48只SD大鼠随机分为对照组、抑制组和诱导组(每组供、受者各8只).对照组:供肝不用任何药物处理;抑制组:在获取供肝前24 h,经供者腹腔注射HO-1抑制剂锌原卟啉20 mg/kg进行预处理;诱导组:在获取供肝前24 h,经供者腹腔注射HO-1诱导剂钴原卟啉5 mg/kg进行预处理.获取供肝后,在4℃UW液中冷保存24 h.肝移植前检测供肝HO-1的表达水平;肝移植后6 h采血并获取移植肝标本,分离培养枯否细胞;检测受者的肝功能;检测枯否细胞培养上清中肿瘤坏死因子α(TNF-α)和白细胞介素6(IL-6)的含量;观察移植肝组织病理学表现以及枯否细胞CD14 mRNA的表达水平和蛋白含量测定.结果 移植前诱导组供肝HO-1的表达水平明显增高.移植后诱导组血清丙氨酸转氨酶(ALT)和天冬氨酸转氨酶(AST)含量明显降低;移植肝组织病理学损伤减轻;枯否细胞培养上清中TNF-α和IL-6含量减少;而且枯否细胞上的CD14 mRNA表达水平和蛋白含量也明显低于抑制组.结论 诱导供肝HO-1表达上调可能抑制了枯否细胞的激活,从而减轻大鼠移植肝缺血再灌注损伤.     

The cumulative effects of cold ischemic time and older donor age on liver graft survival

INTRODUCTION: To provide greater equity among those awaiting a liver transplant, expanded geographic sharing of cadaveric organs has been proposed. A potential unintended consequence could be an increase in cold ischemia time (CIT), which may be deleterious to organs from older donors. This study sought to quantify the relative risk (RR) associated with increased CIT among older donors. METHODS: A retrospective study examining 18,787 liver transplants within the United Network for Organ Sharing database from 2002 to 2006 was performed. Cox Regression analysis was used to model the RR of graft loss with respect to increased CIT among older donors (>60 years) relative to younger donors (<60 years), while controlling for multiple donor and recipient characteristics. RESULTS: Relative to younger donors with minimal CIT (<6 h), a 73.0% increase in the risk of graft loss was observed for older donors with a CIT between 8 and 10 h, a 56.9% increase for CIT between 10 and 12 h, and a 92.7% increase for a CIT of 12 or more hours. Additionally, the RR of graft loss for older donors with minimal CIT (<6 h) was greater than the RR for younger donors with a CIT between 0 and 12 h. CONCLUSION: The additive effects of increased donor age and cold ischemic time greatly impair graft survival. Quantification of the adverse nature of increasing CIT as a potential consequence of wider geographic organ sharing should be considered as allocation policies are modified to improve recipient equity in the face of an aging donor pool.     

丹参对大鼠供肝冷保存缺血再灌注损伤中肝细胞凋亡的影响

目的 探讨丹参对大鼠原位肝移植供肝冷保存缺血再灌注损伤中肝细胞凋亡的影响.方法 将40只SD大鼠分为对照组、实验组及假手术组,建立原位肝移植模型.供肝灌注冷保存以4℃乳酸林格氏液为基液,实验组加丹参注射液(60 ml/L),对照组不加丹参.保存5 h后植入受体.移植后6 h处死大鼠取样,检测血浆中ALT、AST水平;采用TUNEL法检测移植术后肝细胞凋亡情况;流式细胞仪检测凋亡相关基因Bcl-2、FasL蛋白的表达;光镜下观察移植肝脏病理形态学的改变.结果 再灌注后实验组ALT、AST显著低于对照组.与对照组比较,实验组肝细胞凋亡指数明显下降(F=133.802,P<0.05);肝组织中Bcl-2蛋白表达增加(F=91.063,P<0.01);FasL蛋白表达无明显变化(F=1.329,P>0.05);实验组与对照组比较肝组织形态学的再灌注损害程度明显减轻.结论 丹参可通过促进抑制凋亡基因Bcl-2蛋白的表达来抑制冷保存再灌注导致的肝细胞凋亡,对原位肝移植肝脏的缺血再灌注损伤有保护作用.     

钙蛋白酶与肝移植缺血再灌注损伤关系的实验研究

目的 探讨大鼠肝在不同冷缺血期、复温期及再灌注期钙蛋白酶活性变化，以及钙蛋白酶抑制剂对离体灌注肝功能及原位肝移植大鼠生存的影响。方法 SD大鼠。共5个实验部分：（1）冷缺血实验；（2）冷缺血后复温实验；（3）冷缺血后再灌注实验；（4）钙蛋白酶抑制剂实验；（5）原位肝移植实验。结果 冷缺血12h始，肝组织中钙蛋白酶活力明显增加，并随着冷缺血时间的延长而逐渐明显增加（P＜0.01）。冷缺血复温30min始，肝组织中钙蛋白酶活力明显增加，并随着复温时间延长而逐渐明显增加（P＜0.01）。肝组织冷缺血0和12h再灌注60min钙蛋白酶明显增加（P＜0.05）。钙蛋白酶抑制剂明显增加（P＜0.05）。而冷缺血24h再灌注30min钙蛋白酶便明显增加（P＜0.05）。钙蛋白酶抑制剂可明显地降低离体灌注肝AST水平及增加胆汁量（分别P＜0.01）。结论 肝移植冷缺血期、复温期及再灌注期钙蛋白酶均明显增高，钙蛋白酶抑制剂可明显地改善移植肝功能。     

Immediate increase of portal pressure, reflecting sinusoidal shear stress, induced liver regeneration after partial hepatectomy

The mechanisms whereby hepatocytes in the normal liver can be primed for replication following partial hepatectomy (PHx) are poorly understood. To determine whether "shear stress," which is induced by acute portal hypertension after PHx, is involved in liver regeneration, we studied liver regeneration in rats with splenic transposition (SPT) in which we can minimize the postoperative elevation of portal pressure. Rats underwent 70% PHx following splenic transposition or sham surgery and were killed at various time points to measure portal pressure and other factors. In the control groups, the portal pressure was significantly increased immediately after surgery, peaking at 48 h, and returning to near the preoperative levels by 168 h after PHx. In the SPT group, although portal pressure increased immediately, it decreased to the control levels 6 h after PHx and thereafter repeatedly increased. Tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels peaked at 24 and 6 h after PHx, respectively. Proliferative cell analysis was done using MIB-5 antibody, and there were no significant differences between the two groups. Furthermore, liver weight was restored in the same way in both groups. Taken together, the results suggest that an immediate increase in portal pressure is necessary for the initiation of liver regeneration. Received for publication on Jan. 20, 1999; accepted on Feb. 25, 1999