Remote hindlimb preconditioning and hepatoprotection: NO-table strides against liver ischaemia/reperfusion injury

Hepatic IR (ischaemia/reperfusion) injury is an important clinical problem complicating liver surgery and transplantation. IPC (ischaemic preconditioning) is a strategy whereby brief episodes of IR in an organ can induce an adaptive response to protect against subsequent prolonged IR injury. However, trauma to vessels supplying the target organ is unavoidable using the technique of direct IPC. One amenable strategy would be to apply the protective preconditioning stimulus to an organ distant or remote from the target organ of interest, a technique known as RIPC (remote IPC). In the present issue of Clinical Science, Abu-Amara and co-workers utilize hindlimb RIPC as a novel therapeutic strategy against liver IR injury and investigate the mechanistic contribution of NO to hepatoprotection by administering C-PTIO [2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide potassium salt], an NO scavenger. Their experiments set the stage for more definitive studies to demonstrate a discernible benefit for the utility of RIPC in liver surgery and transplantation.     

肝细胞生长因子对肝再灌注损伤的治疗作用

目的：观察肝细胞生长因子(HGF)对肝缺血再灌注(IR)损伤的治疗作用并探讨其作用机制。方法：建立大鼠肝缺血再灌注损伤模型，在恢复灌注后立即经静脉给予HGF0．5mg／kg，以后每12h给药1次，而对照组仅给予平衡盐治疗。均检测肝功能、组织病理学变化以及肝脏重量变化，还利用免疫组化方法检测肝细胞PCNA表达情况，利用TUNEL法检测肝细胞凋亡情况。结果：在HGF治疗组，恢复灌注后血清ALT与透明质酸水平均明显下降。血清白蛋白水平升高。恢复灌注后24h在HGF治疗组肝坏死范围下降，TUNEL法检测恢复灌注后6h在HGF治疗组凋亡肝细胞下降。结论：HGF可促进IR造成的肝损伤的恢复，在IR损伤治疗中可能发挥一定的作用。     

Inhaled NO accelerates restoration of liver function in adults following orthotopic liver transplantation

Ischemia/reperfusion (IR) injury in transplanted livers contributes to organ dysfunction and failure and is characterized in part by loss of NO bioavailability. Inhalation of NO is nontoxic and at high concentrations (80 ppm) inhibits IR injury in extrapulmonary tissues. In this prospective, blinded, placebo-controlled study, we evaluated the hypothesis that administration of inhaled NO (iNO; 80 ppm) to patients undergoing orthotopic liver transplantation inhibits hepatic IR injury, resulting in improved liver function. Patients were randomized to receive either placebo or iNO (n = 10 per group) during the operative period only. When results were adjusted for cold ischemia time and sex, iNO significantly decreased hospital length of stay, and evaluation of serum transaminases (alanine transaminase, aspartate aminotransferase) and coagulation times (prothrombin time, partial thromboplastin time) indicated that iNO improved the rate at which liver function was restored after transplantation. iNO did not significantly affect changes in inflammatory markers in liver tissue 1 hour after reperfusion but significantly lowered hepatocyte apoptosis. Evaluation of circulating NO metabolites indicated that the most likely candidate transducer of extrapulmonary effects of iNO was nitrite. In summary, this study supports the clinical use of iNO as an extrapulmonary therapeutic to improve organ function following transplantation.     

异氟醚预处理对缺血/再灌注复合内毒素大鼠肝脏损伤的影响

目的 观察再灌注期腹腔注射内毒素脂多糖(LPS)对大鼠肝脏缺血/再灌注(I/R)损伤的影响以及异氟醚(ISO)预处理的干预作用.方法 将32只SD大鼠随机均分为4组:假手术(Sham)组、单纯肝脏I/R组、肝脏I/R复合LPS损伤(I/R+LPS)组及ISO预处理组.I/R+LPS组吸氧预处理后间隔0.5 h进行肝脏缺血1 h、再灌注4 h,再灌注开始时腹腔内注入LPS;ISO预处理组以ISO吸入预处理0.5 h,间隔0.5 h后进行I/R损伤操作,再灌注开始时腹腔内注入LPS.再灌注4 h处死各组动物,留取肝脏及血液标本;观察各组肝组织病理学改变,血清丙氨酸转氨酶(ALT)、天冬氨酸转氨酶(AST)、肿瘤坏死因子-α(TNF-α)的变化以及肝组织TNF-α、髓过氧化物酶(MPO)活性的改变.结果 与Sham组比较,损伤各组血清ALT、AST、TNF-α及肝组织TNF-α、MPO活性均显著升高(P均＜0.01);与I/R组比较,I/R+LPS组肝脏损伤和炎症细胞因子反应明显较重(P＜0.05或P＜0.01)l与I/R+LPS组比较,ISO预处理组肝脏的病理损伤明显较轻,血清ALT、AST、TNF-α水平及肝组织MPO活性和促炎细胞因子TNF-α的表达水平均显著降低(P均＜0.05).结论 再灌注期复合LPS腹腔注射明显加重了肝脏的损伤和炎症细胞因子反应,ISO预处理可明显减轻复合损伤介导的炎症反应,保护肝脏.     

远程缺血预处理对大鼠局灶性脑缺血/再灌注损伤的保护作用

目的探讨远程缺血预处理(RIPC)对大鼠局灶性脑缺血/再灌注(I/R)损伤的影响。方法SD雄性大鼠70只,随机分组,每组10只。对照组仅行单纯缺血后再灌注;RIPC组按RIPC与脑缺血间隔时间不同分为30min及1、2、12、24和48h组,即反复3次夹闭双侧股动脉造成肢体缺血5min、再灌注5min后,分别间隔30min及1、2、12、24和48h后,行大脑中动脉栓塞(MCAO)120min、再灌注24h。对各组动物进行神经功能缺损评分,然后行氯化三苯四唑(TTC)染色,计算脑梗死容积。结果与对照组比较,RIPC1、2和24h组神经功能缺损评分显著下降,差异有显著性(P均<0.05);而RIPC30min、12h和48h组与对照组比较差异均无显著性(P均>0.05)。脑梗死容积百分比RIPC1h组〔(17.9±7.5)%,P=0.016〕、2h组〔(18.3±11.2)%,P=0.019〕和24h组〔(20.2±11.9)%,P=0.047〕均明显小于对照组〔(30.5±9.8)%〕;而RIPC30min、12h和48h组与对照组比较差异无显著性(P均>0.05)。结论RIPC对大鼠局灶性脑I/R损伤有保护作用,其保护时程为预处理后1～2h,24h后再次出现。     

Effect of ischaemic preconditioning on hepatic oxygenation, microcirculation and function in a rat model of moderate hepatic steatosis

IPC (ischaemic preconditioning) may protect the steatotic liver, which is particularly susceptible to I/R (ischaemia/reperfusion) injury. Hepatic steatosis was induced in Sprague-Dawley rats with a high-cholesterol (2%) diet for 12 weeks after which rats were subjected to I/R (ischaemia/reperfusion; 45 min of lobar ischaemia followed by 2 h of reperfusion). Rats were divided into three study groups (n=6 each) receiving: (i) sham laparotomy alone, (ii) I/R, and (iii) IPC (5 min of ischaemia, followed by 10 min of reperfusion) before I/R. Hepatic extra- and intra-cellular oxygenation and HM (hepatic microcirculation) were measured with near-infrared spectroscopy and laser Doppler flowmetry respectively. Plasma liver enzymes and hepatic tissue ATP were measured as markers of liver injury. Histology showed moderate-grade steatosis in the livers. At the end of 2 h of reperfusion, I/R significantly decreased extra- and intra-cellular oxygenation concomitant with a failure of recovery of HM (21.1+/-14.4% of baseline; P<0.001 compared with sham animals). IPC increased intracellular oxygenation (redox state of the copper centre of cytochrome oxidase; P<0.05 compared with rats receiving I/R alone) and flow in HM (70.9+/-17.1% of baseline; P<0.001 compared with rats receiving I/R alone). Hepatocellular injury was significantly reduced with IPC compared with I/R injury alone (alanine aminotransferase, 474.8+/-122.3 compared with 5436.3+/-984.7 units/l respectively; P<0.01; aspartate aminotransferase, 630.8+/-76.9 compared with 3166.3+/-379.6 units/l respectively; P<0.01]. In conclusion, IPC has a hepatoprotective effect against I/R injury in livers with moderate steatosis. These data may have important clinical implications in liver surgery and transplantation.     

Pyrrolidine dithiocarbamate protects the small bowel from warm ischaemia/reperfusion injury of the intestine: the role of haem oxygenase

IR (ischaemia/reperfusion) injury of the intestine occurs commonly during abdominal surgery. We have previously shown that PDTC (pyrrolidine dithiocarbamate), an HO-1 (haem oxygenase-1) donor, improves intestinal microvascular perfusion. In the present study, we have investigated the effects of PDTC on the intestinal microcirculation following IR (ischaemia/reperfusion) injury of the intestine. Male Sprague-Dawley rats (n=72) were randomly assigned to four groups (n=18/group): (i) sham-operated group, who underwent laparotomy without induction of IR of the intestine; (ii) IR group, who were subjected to 30 min of superior mesenteric artery occlusion and 2 h of reperfusion; (iii) PDTC+IR group, who received PDTC prior to IR; and (iv) ZnPP group, who received the HO-1 inhibitor ZnPP (zinc protoporphyrin) followed by procedures as in group (iii). The ileum was evaluated for changes in tissue cytochrome c oxidase redox status, RBC (red blood cell) dynamics and leucocyte-endothelial interactions. The expression of HO-1 in the ileal tissue was examined at the end of the reperfusion. PDTC significantly improved the intestinal tissue oxygenation, mucosal perfusion index and RBC velocity compared with the IR and ZnPP groups. PDTC also decreased the leucocyte-endothelial interactions (P<0.05 compared with the IR and ZnPP groups). PDTC induced the expression of HO-1, whereas ZnPP abolished this effect.     

缺血预处理减轻大鼠减体积肝移植损伤并促进肝再生

背景:近年来,肝移植技术迅速发展,如何预防缺血再灌注损伤并有效保护肝再生成为研究的热点.缺血预处理是保护肝缺血损伤的有效方法,但其确切机制尚存争议.目的:研究缺血预处理在大鼠减体积肝移植肝损伤和肝再生中的作用及机制.方法:动物随机分为3组,肝移植组建立大鼠减体积肝移植模型.缺血预处理+肝移植组在供肝灌注前阻断第1肝门行缺血预处理10 min,再灌注15 min.假手术组在开腹后游离肝周韧带,然后关腹.分别于术后0.5,2,6,24 h取材.通过血清谷丙转氨酶水平和移植肝组织病理检查评估肝损伤.半定量免疫组织化学和western blot法测定氧化还原蛋白1表达水平,检测移植肝细胞增殖细胞核抗原评估肝再生情况.结果与结论:与肝移植组相比,缺血预处理+肝移植组术后6,24 h受体血清谷丙转氨酶明显降低(P<0.05;P<0.01).病理学分析显示肝移植组术后24 h可见到门脉周围大量炎细胞浸润,肝窦扩张明显,肝组织损伤较重;而缺血预处理+肝移植组则损伤较轻.半定量免疫组织化学显示缺血预处理+肝移植组移植肝中Ref-1蛋白表达明显增加,这一结果同样在westernblot检测中得到验证:缺血预处理+肝移植组移植肝术后24 h Ref-1蛋白表达较肝移植组明显增强(P<0.05).同时,术后2,6和24 h缺血预处理+肝移植组增殖细胞核抗原阳性细胞数较肝移植组明显增加(P<0.05).结果提示缺血预处理可减轻大鼠减体积肝移植术后早期移植物肝损伤并促进肝再生,这与Ref-1蛋白高表达密切相关.     

运动预处理对心肌缺血再灌注损伤老龄大鼠心肌的影响

目的:观察运动预处理对心肌缺血再灌注损伤后老龄大鼠心功能、心肌梗死面积、心肌细胞超微结构及抗氧化能力的影响。方法:选择60只SPF级雄性SD老龄大鼠按照随机数字表法分为对照组(Con组)、缺血再灌注模型组(IR组)、运动预处理+缺血再灌注组(EP+IR组)、缺血预适应组(IPC组)、运动预处理+缺血预适应组(EP+IPC组),每组12只。Con组、IR组、IPC组不做特殊运动干预;EP+IR组、EP+IPC组接受运动预处理干预(采用电动动物实验跑台进行梯度运动训练,1次/d,5 d/周,共训练6周)。利用Langendorff装置制备老龄大鼠离体心肌缺血/再灌注模型,具体如下:Con组仅进行心肌离体灌流,持续平衡灌注180 min,不进行缺血操作;IR组平衡预灌注20 min,然后保持心脏温度恒定在37℃,通过控制灌流设备的三通阀,使全心缺血40 min,再复灌120 min;EP+IR组大鼠心脏离体后,模型制备方法同IR组;IPC组大鼠心脏离体后平衡灌注20 min,给予3次缺血预处理(短暂缺血5 min,再灌注10 min),之后缺血40 min,再复灌120 min;EP+IPC组大鼠心脏离体后,模型制备方法同IPC组。于再灌注前、再灌注30、60、120 min分别采用多导生理记录仪记录心脏功能变化;于再灌注结束后,采用TTC染色法测定心肌梗死面积,比色法检测冠脉流出液中LDH活性、心肌组织中MDA含量及SOD活力。结果:(1)心脏功能指标:与Con组同一时间点比较,IR组再灌注前、再灌注后30、60、120 min心功能各项指标[心率(CR)、左心室舒张压(LVDP)、左心室压力最大变化速率(±dp/dtmax)、冠脉流量(CF)]均明显降低(P<0.05)。与IR组同一时间点比较,EP+IR、IPC、EP+IPC组再灌注30、60、120 min心功能各项指标均明显升高(P<0.05)。与IPC组同一时间点比较,EP+IPC组再灌注30、60、120 min心功能HR、±dp/dt_max、CF均明显更高(P<0.05)。(2)心肌梗死面积:与Con组比较,IR组心肌梗死面积明显增大(P<0.05);与IR组比较,EP+IR、IPC、EP+IPC组心肌梗死面积明显缩小(P<0.05)。(3)LDH活性、MDA含量、SOD活力:与Con组比较,IR组LDH活性水平明显升高(P<0.05);与IR组比较,EP+IR、IPC、EP+IPC组LDH活性水平降低(P<0.05);与EP+IR、IPC组比较,EP+IPC组LDH活性水平明显更低(P<0.05)。与Con组比较,IR组MDA含量明显升高,SOD活力明显降低(P<0.05);与EP+IR、IPC组比较,EP+IPC组MDA含量明显更低,SOD活力明显更高(P<0.05)。结论:运动预处理可诱导老龄大鼠心肌IPC保护作用,能有效改善心肌缺血再灌注损伤老龄大鼠心脏功能,减小心肌梗死面积,减轻心肌细胞损伤,这可能与其降低心肌缺血/再灌注时心肌LDH活性、MDA含量,提高SOD活力,增强心肌抗氧化能力有关。     

Ischaemic and pharmacological preconditionings protect liver via adenosine and redox status following hepatic ischaemia/reperfusion in rats

Although IPC (ischaemic preconditioning) is considered as a protective strategy in HI/R (hepatic ischaemia/reperfusion), the mechanisms for this effect have not been fully elucidated. In the present study we investigate whether PPC (pharmacological preconditioning) by transient activation of A(1)R (adenosine A(1) receptor) protects against long-term HI/R and whether the protective effects of IPC depend on A(1)R activation and whether both preconditionings affect remote organs. Wistar rats underwent IPC and long-term HI/R. Another set of animals were pharmacologically preconditioned with the A(1)R-agonist CCPA [2-chloro-N(6)-cyclopentyladenosine; 0.1 mg/kg of body weight, i.p. (intraperitoneally)] 24 h before HI/R. In other groups, rats received an A(1)R-antagonist, DPCPX (1,3-dipropyl-8-cyclopentylxanthine; 0.1 mg/kg of body weight, i.p.) 24 h before HI/R. Hepatic damage was evaluated by transaminase [AST (aspartate transaminase), ALT (alanine transaminase)] release; inflammation was assessed by hepatic MPO (myeloperoxidase) and serum TNFalpha (tumour necrosis factor alpha) and NO; oxidative stress was estimated by MDA (malondialdehyde) and 4-HDA (4-hydroxyalkenals), SOD (superoxide dismutase) activity, GSH and ADA (adenosine deaminase) as adenosine metabolism. Both preconditionings protected liver and lung against HI/R as indicated by the reduction in transaminases, MPO, MDA+4-HDA, NO, TNFalpha and ADA activity as compared with HI/R (P<0.05). However, pre-treatment with DPCPX abolished the protective effects of IPC and PPC. Preconditionings induced a significant increase in hepatic MnSOD (manganese SOD) activity and NO generation compared with the sham group, and this activity was abolished by DPCPX pre-treatment. A(1)R activation induced hepatic delayed preconditioning and blockade of A(1)R abolished hepatic IPC. IPC, as well as PPC, were able to prevent lung damage. These protective effects are associated with a reduction in oxidative stress, inflammation and endogenous antioxidant preservation.     

缺血预处理减轻胰腺移植受体大鼠小肠肠黏膜屏障的损害

背景:胰腺移植过程中的缺血再灌注损伤可以引起术后众多的并发症,其中继发性胰腺炎可以导致受体小肠黏膜的损伤,造成严重的后果。目的:观察缺血预处理对大鼠胰腺移植受体肠黏膜屏障的保护作用。设计:随机对照动物实验。单位:解放军第四军医大学西京医院胃肠外科。材料:实验于2001-09/2004-04在解放军第四军医大学西京医院胃肠外科实验室完成。动物为SD雄性大鼠83只。方法:①取47只大鼠,自阴茎静脉注射脲链霉素65mg/kg制备糖尿病大鼠模型。将造模成功的36只大鼠随机分为缺血再灌注组,供体缺血预处理组(DIPC组),受体双后肢缺血预处理组(RIPC组)3组,每组12只。剩余36只正常大鼠中随机取12只为对照组,另外24只为供体。②对照组仅行开腹术,其他3组行胰腺移植。DIPC组于获取供胰前阻断供体脾血管5min再灌注5min2次;RIPC组于供胰再灌注前阻断受体双后肢血流5min再灌注5min,重复3次;缺血再灌注组不作处理。主要观察指标:①手术后5d各组随机取6只大鼠检测小肠通透性(以血浆中FITC-dextran浓度表示)和吸收功能(以血浆中木糖浓度表示)。②各组其余6只大鼠于术后5d取血检测血清肿瘤坏死因子α、NO、超氧化物歧化酶和淀粉酶活性,取回肠黏膜组织检测小肠黏膜黏膜湿重、微绒毛高度及宽度、丙二醛含量及髓过氧化物酶活性,同时取肠系膜淋巴结、肝及脾组织进行细菌培养,观察细菌易位情况。结果:经补充后72只大鼠进入结果分析。①血浆中FITC-dextran浓度:缺血再灌注组高于对照组、DIPC组和RIPC组(P<0.01)。②血浆中木糖浓度:缺血再灌注组低于对照组、DIPC组和RIPC组(P<0.01)。③细菌易位率:缺血再灌注组高于对照组、DIPC组和RIPC组(P<0.01)。④小肠黏膜损伤程度:缺血再灌注组低于其他3组(P<0.01)。⑤缺血再灌注组小肠髓过氧化物酶活性和丙二醛含量显著高于其他3组(P<0.01),血清超氧化物歧化酶活性和NO水平低于其他3组,淀粉酶活性和肿瘤坏死因子α水平高于其他3组(P<0.01)。结论:供体和受体双后肢缺血预处理均可保护大鼠胰腺移植受体小肠肠黏膜屏障,降低细菌易位率     

Protective antioxidant effects of carvedilol in a rat model of ischaemia-reperfusion injury

This study investigated the protective effects of carvedilol, a potent antioxidant, in a rat model of tourniquet-induced ischaemia-reperfusion injury of the hind limb. Thirty rats were divided equally into three groups: the control group (group 1) was only anaesthetized, without creating an ischaemia-reperfusion injury; group 2 was submitted to ischaemia (4 h), followed by a 2-h reperfusion period; and group 3 was pre-treated with carvedilol (2 mg/kg per day) for 10 days prior to ischaemia-reperfusion. Ischaemia-reperfusion produced a significant decrease in superoxide dismutase and glutathione peroxidase activities in the liver, lungs, muscle and serum compared with control treatment, and pre-treatment with carvedilol prevented these changes. Ischaemia-reperfusion caused a significant increase in malondialdehyde and nitric oxide (NO) levels in liver, lungs, muscle (except NO) and serum compared with control treatment, and carvedilol prevented these changes. In conclusion, it might be inferred that carvedilol could be used safely to prevent oxidative injury during reperfusion following ischaemia in humans.     

右美托咪定联合缺血预处理对大鼠肝缺血再灌注损伤的作用

目的探讨右美托咪定联合缺血预处理对大鼠肝缺血-再灌注损伤的作用及可能机制。方法60只健康雄性 SD 大鼠,体质量（251±18）g,按随机数字表法分为五组（n ＝12）：假手术组（S 组：不阻断入肝血流）、缺血-再灌注组（IR 组：缺血30 min,再灌注6 h）、右美托咪定预处理组（Dex 组：右美托咪定25μg／kg 于手术30 min 前腹腔注射）、缺血预处理组（IP 组：肝脏续缺血前给予10 min 缺血和10 min 再灌注的预处理）和右美托咪定联合缺血预处理组（Dex ＋IP组：右美托咪啶25μg／kg 于手术30 min 前腹腔注射,且肝脏持续缺血前给予10 min 缺血和10 min再灌注的预处理）。采用 Pringle 法分别建立大鼠肝脏缺血-再灌注模型,测定肝脏缺血30 min 再灌注6 h 后血清中 ALT、AST、LDH 的浓度。取左侧肝叶组织,通过 HE 染色观察其病理学改变, TUNEL 检测肝脏组织中细胞凋亡数量,免疫组化及 Westeren blot 测定肝脏组织血红素氧合酶-1的表达,分光光度法检测肝脏组织 H2 O2、GSH 表达。采用 SPSS 17.0统计软件,多组间比较采用单因素方差分析,两组间比较采用 q 检验,以 P ＜0.05为差异有统计学意义。结果与 S 组相比,其余各组血清中 ALT、AST、LDH 浓度明显增高（P ＝0.000）;与 IR 组相比,Dex 组、IP 组及 Dex ＋IP 组明显降低（P ＝0.000）;Dex ＋IP 组明显低于 Dex 组及 IP 组（P ＝0.000）;ALT 及 AST 浓度在Dex 组与 IP 组之间差异无统计学意义（P ＝0.550,0.771）,LDH 浓度在 Dex 组明显低于 IP 组（P＝0.000）。肝组织病理学评分及细胞凋亡指数 S 组最低,IR 组最高,Dex 组及 IP 组明显低于 IR 组（P ＝0.000）,Dex ＋IP 组明显低于 Dex 组及 IP 组（P ＝0.000）,Dex 组与 IP 组之间差异无统计学意义（P ＝0.704,0.661）。肝组织中血红素氧合酶-1表达 S 组最低,Dex ＋IP 组最高,Dex 组及 IP 组低于 Dex ＋IP 组（P ＝0.000,0.002）,IR 组低于 Dex 组及 IP 组（P ＝0.000）,Dex 组及 IP 组之间差异无统计学意义（P ＝0.099）。与 S 组相比,IR 组、Dex 组、IP 组及 Dex ＋IP 组肝脏组织 H2 O2活性明显增高（P ＝0.000,0.000,0.000,0.001）,GSH 活性明显降低（P ＝0.000）;与 IR 组相比,Dex 组及 IP 组 H2 O2活性明显降低,GSH 活性明显增高（P ＝0.000）;与 Dex 组及 IP 组相比, Dex ＋IP 组 H2 O2活性明显降低,GSH 活性明显增高（P ＝0.000）;Dex 组与 IP 组之间差异无统计学意义（P ＝0.480,0.667）。结论右美托咪定及缺血预处理对大鼠肝缺血-再灌注损伤均有保护作用,两者联合应用效果更好,其作用可能均与诱导 HO-1的表达有一定关系。     

Trimetazidine prevents ischemia-reperfusion injury in hepatic surgery under vascular clamping]

Clamping the hepatic pedicle (or Pringle's manoeuvre) is frequently used to reduce blood loss during liver surgery. This induces a normothermic ischaemia of the overall liver. In this study we have investigated the anti-ischaemic effect of trimetazidine during surgery on hydatid cysts of the liver requiring vascular clamping of the hepatic pedicle. Seventy-six hepatic pericystectomies were performed under a 40 min normothermic ischaemia. Two randomized groups including 38 patients each received daily either trimetazidine (80 mg/kg, group 1) or placebo (group 2) for 5 days before surgery. The effect of trimetazidine was evaluated on different parameters, the macroscopic appearance of the tissue, the ATP content in liver biopsies obtained before and after 15, 30 and 60 min reperfusion, the activity of the aminotransferase in the plasma and the plasma concentrations of reduced and oxidized gluthatione. No mortality was observed. The duration of hospital stay was reduced for patients treated with trimetazidine (8 +/- 1 days compared with 11 +/- 1.5 days for patients in group 2; p < 0.05). Morbidity rate was lower in group 1 (11 per cent) than in group 2 (18.5 per cent) but the decrease was not significant. Trimetazidine treatment reduced cytolysis (p < 0.05 on day 1, day 3, day 5), increased liver ATP content and limited the increase of reduced and oxidized gluthatione in the plasma during reperfusion. These results suggest that trimetazidine alleviates ischaemia-reperfusion injury during liver surgery and may allow extension of the ischaemic period without damage to the liver.     

N-Acetylcysteine ameliorates the late phase of liver ischaemia/reperfusion injury in the rabbit with hepatic steatosis

Steatotic livers are highly susceptible to I/R (ischaemia/reperfusion) injury and, therefore, the aim of the present study was to evaluate the in vivo effect of NAC (N-acetylcysteine) on hepatic function in the early and initial late phase of warm liver I/R injury in steatotic rabbits. Twelve New Zealand White rabbits were fed a high-cholesterol (2%) diet. The control group (n=6) underwent lobar liver ischaemia for 1 h, followed by 6 h of reperfusion. In the treated group receiving NAC (n=6), an intravenous infusion of NAC was administered prior to and during the 6 h reperfusion period. Systemic and hepatic haemodynamics were monitored continuously. ALT (alanine aminotransferase) activity and bile production were measured. NMR spectroscopy was used to analyse bile composition. Oxidation of DHR (dihydrorhodamine) to RH (rhodamine) was used as a marker of production of reactive oxygen and nitrogen species. Moderate centrilobular hepatic steatosis was demonstrated by histology. The results showed that NAC administration significantly improved portal flow, hepatic microcirculation, bile composition and bile flow after 5 h of reperfusion. NAC administration was also associated with less hepatocellular injury, as indicated by ALT serum activity, and decreased the oxidation of DHR to RH. In conclusion, NAC administration decreased the extent of I/R injury in the steatotic liver, particularly during the late phase of reperfusion.     

参附注射液对兔肝脏缺血再灌注损伤保护作用的研究

目的研究参附注射液对兔肝脏缺血再灌注损伤的保护作用及其机理。方法 27只新西兰大白兔随机分为3组:对照组(A组)、缺血再灌注组(B组)、参附治疗组(C组)。分别在缺血前10min,缺血45min,再灌注45min取血检测肝功能、超氧化物歧化酶(SOD)、丙二醛(MDA)、肿瘤坏死因子(TNF-α)、白介素10(IL-10)、一氧化氮(NO)及肝组织标本行病理学观察。结果 C组与B组相比,再灌注45min肝酶指标、血浆MDA浓度、TNF-α浓度降低;血浆SOD活力、血浆IL-10浓度、血浆NO浓度升高,差异有统计学意义(t分别=-3.38～3.76,P均<0.05);病理检查提示C组肝脏变性坏死明显较B组减轻。结论参附注射液能增强兔血浆SOD活力,清除氧自由基,抑制脂质过氧化反应;抑制肝脏Kupffer细胞产生TNF-α,促进内源性IL-10的释放;促进肝脏合成释放NO,对兔肝脏缺血再灌注损伤有明显的保护作用。     

聚合人脐带血血红蛋白预处理对肝缺血/再灌注损伤的保护作用

目的探讨聚合人脐带血血红蛋白(PolyPHb)预处理对SD大鼠肝脏缺血/再灌注(I/R)损伤的保护作用。方法采用随机分组对照研究的方法,将30只成年雄性SD大鼠平均分为假手术(Sham)组、I/R组和PolyPHb预处理(PolyPHb)组;采用大鼠70%肝I/R损伤模型,缺血前I/R组和PolyPHb组动物分别静脉推注生理盐水和PolyPHb(0.3 gHb/kg)预处理,然后缺血60 min,再灌注3 h。检测术前及术后丙氨酸转氨酶(ALT)和谷草转氨酶(AST)活性,并采集术后肝脏组织标本行HE染色和TUNEL染色。结果 PolyPHb组、I/R组的肝酶释放ALT、AST分别为(350.9±80.8)U/L vs(830.5±85.7)U/L(P<0.01)和(446.1±97.10)U/L vs(1 096.2±135.6)U/L(P<0.01),肝细胞凋亡发生率分别为(15.62±8.58)%vs(35.21±9.62)%(P<0.01)。结论 PolyPHb预处理对大鼠肝脏I/R损伤具有明显的保护作用。     

异丙酚对兔肝缺血/再灌注损伤中一氧化氮和内皮素的干预

目的　探讨一氧化氮 (NO)和内皮素 (ET)在肝缺血 /再灌注损伤 (HIRI)中的作用及异丙酚对其的影响。方法　实验兔分为假手术对照组 (n =10 )、肝缺血 /再灌注组 (n =10 )及肝缺血 /再灌注 异丙酚治疗组 (n =10 ) ;分别检测缺血前、缺血 4 5min和再灌注 4 5min 3个时点的指标变化。用硝酸还原酶法检测血浆及肝组织一氧化氮代谢产物 (NOP)含量 ,放射免疫法测定ET水平 ,赖氏法测定谷丙转氨酶 (ALT)活性 ,并行肝组织电镜观察。结果　肝缺血 /再灌注期间 ,血浆NOP明显低于假手术对照组 ,而ET及ALT显著高于假手术对照组 ,尤以再灌注 4 5min变化显著 (P <0 0 5和P <0 0 1) ;肝组织NOP明显低于假手术对照组 ,而ET显著高于假手术对照组 (P <0 0 5和P <0 0 1) ;肝细胞形态学发生异常改变。异丙酚可逆转上述指标的异常变化。结论　缺血 /再灌注导致血管内皮功能紊乱 (即NO水平下降和ET水平升高 ) ,在HIRI发生发展中起介导作用 ;异丙酚通过保护肝窦内皮 ,提高机体内NO水平和降低机体内ET水平 ,从而减轻HIRI。     

二氮嗪预处理对大鼠肝窦内皮常温缺血再灌注损伤的影响

目的:通过观察二氮嗪(Diazoxide)预处理对大鼠肝窦内皮常温缺血再灌注损伤(I/RI)的影响,探讨线粒体ATP敏感性钾通道(MitoKATP)在其中的可能作用。方法:32只成年健康雄性SD大鼠,随机分为4组,每组8只:①假手术组(Sham组);②对照组(Control组),进腹后行部分肝脏缺血再灌注(I/R);③二氮嗪组(Dia组),在行肝I/R前10min,静注Diazoxide (5 mg·kg~(-1));④5-HD Dia组,在行肝I/R之前20min静注5-HD(10mg·kg~(-1)),10min后静注Diazoxide(5 mg·kg~(-1))。再灌注90min时测定各组血清谷丙转氨酶(ALT)、透明质酸(HA)水平和肝脏一氧化氮(NO)、内皮素(ET)含量;并进行肝组织病理形态学观察,包括光镜HE染色和透射电镜(TEM)超微结构检查;免疫组化检测细胞间粘附分子(ICAM-1)的表达。结果:与Sham组相比,Control组的血清ALT和HA水平,肝组织ET含量均明显升高(P<0.05);而肝组织NO含量明显降低(P<0.05)。与Control组相比,Dia组的ALT、HA及ET含量都降低(P<0.05)。肝组织中NO的含量升高。5-HD完全抵消了Dia的作用。HE染色和TEM检查提示Dia组较明显地减轻损伤,而5-HD Dia组则与Control组相似。Dia组肝窦内皮细胞膜ICAM-1表达比例明显减少,且染色较淡,组间比较有显著差异(P<0.05);5-HD可以抵消Diazoxide减少ICAM-1表达的效应。结论:线粒体ATP敏感性钾通道(MitoKATP)开放剂的预处理对后继的肝脏I/RI中肝窦内皮的损伤有较好的保护作用。     

Ischemic preconditioning protects against gut dysfunction and mucosal injury after ischemia/reperfusion injury

Mesenteric ischemia/reperfusion (IR) damages the gastrointestinal epithelia and impairs gut function. Ischemic preconditioning (IPC) has been shown to protect organs against IR injury. We hypothesized that IPC protects the gut from IR injury. Rats were randomized to a sham group, a sham early IPC + IR group (sham IPC + SMA occlusion for 30 min and 6 h of reperfusion), an early IPC + IR group (IPC, three cycles of SMA occlusion for 4 min and reperfusion for 10 min) followed immediately by SMA occlusion for 30 min and 6 h of reperfusion), a sham 24-h group, a sham late IPC + IR group (sham IPC followed by additional reperfusion for 24 h + SMA occlusion for 30 min and 6 h of reperfusion), and a late IPC + IR group (IPC protocol followed by additional reperfusion for 24 h, and then SMA occlusion for 30 min followed by 6 h of reperfusion). At 6 h, transit was determined and expressed as the mean geometric center. Ileum was harvested for assessment of mucosal injury and myeloperoxidase (MPO) activity. Tissue water was determined using the wet-to-dry weight ratio to assess gut edema. Early IPC + IR significantly improved transit (3.9 +/- 0.2), decreased MPO levels (3 +/- 2), and lessened mucosal injury (1.2 +/- 0.3) compared with animals subjected to sham early IPC + IR (transit, 2.9 +/- 0.2; MPO levels, 9 +/- 1; mucosal injury, 3.0 +/- 0.6). Late IPC + IR also improved transit (6.0 +/- 0.4) and decreased MPO levels (1 +/- 1) compared with sham late IPC + IR (transit, 4.4 +/- 0.2; MPO levels, 8 +/- 1), however, there was no difference in the mucosal protection between late IPC + IR (1 +/- 0.3) and sham late IPC + IR (1 +/- 1). Our results suggest that early and late IPC improves intestinal dysfunction, decreases inflammation, and provides mucosal protection in the intestine after IR. Our results show that IR-induced gut dysfunction can be improved by IPC. Both phases of IPC can potentially be useful in the clinical setting of surgical patient care.