The roles of platelet-activating factor and endothelin-1 in renal damage after total hepatic ischemia and reperfusion

BACKGROUND: This study was designed to verify the involvement of platelet-activating factor (PAF) in renal damage associated with hepatic ischemia and reperfusion (HIR) injury through the release of endothelin (ET)-1 and to determine the modulating effect of a specific PAF receptor antagonist on these insults in rats. METHODS: Male rats pretreated with either normal saline as a vehicle (NS group) or intravenous TCV-309, a PAF receptor antagonist (TCV group), were subjected to 120 min of total hepatic ischemia under an extracorporeal portosystemic shunt. Plasma aspartate transaminase, creatinine, blood urea nitrogen, and ET-1 levels and the relative renal wet weight were determined under nonischemic conditions and at 1, 3, and 6 hr of reperfusion after hepatic ischemia. Changes in mean arterial blood pressure and renal tissue blood flow measurements in the kidney were determined throughout the experiment. RESULTS: Increased plasma aspartate transaminase, creatinine, blood urea nitrogen, and ET-1 levels and the relative renal wet weight after HIR in the NS group were significantly suppressed by TCV-309 pretreatment. Mean arterial blood pressure and renal tissue blood flow after HIR in the TCV group were significantly improved when compared with those in the NS group. These effects resulted in attenuation of structural hepatic and renal damage with the improvement of 7-day survival (62%). CONCLUSIONS: The present study demonstrates that renal damage as well as critical liver injury is produced after reperfusion following 120 min of total hepatic ischemia. A PAF receptor antagonist may be therapeutically useful to protect against these types of damage via indirect modulation of plasma ET-1 levels.     

Intermittent Ischemic Preconditioning Protects Against Hepatic Ischemia-Reperfusion Injury and Extensive Hepatectomy in Steatotic Rat Liver

ABSTRACT

Background: Hepatic steatosis causes severe liver damage and has deleterious effects when associated with ischemia-reperfusion mechanisms. Ischemic preconditioning (IPC) protects lean liver against prolonged ischemia by improving micro-circulation and reducing lipid peroxidation. We investigated the effect of intermittent IPC on liver ischemia-reperfusion injury (IRI) and extensive hepatectomy in severe hepatic steatosis. Methods: Severe hepatic steatosis was performed by 12–14 weeks of choline-free diet in 108 Wistar rats. We induced 30-minute ischemia-reperfusion manipulations and extensive hepatectomy with or without prior IPC in steatotic livers and after 6 and 24 hours of reperfusion blood transaminases, and IL6, TNFα, NO and Lactate in blood and liver tissue were measured. Results: Steatotic rats subjected to hepatic ischemia-reperfusion alone after extensive hepatectomy, showed severe liver damage with significantly increased values of AST, ALT, TNFα and Lactate and significantly reduced IL6 and NO, while no one rat survived for more than 29 hours. On the contrary, steatotic rats subjected to intermittent IPC, 24 hours before ischemia-reperfusion, presented increased 30-day survival (67%), lower values of AST, ALT, TNFα and Lactate, and increased IL6 and NO levels. Simple and intermittent IPC manipulations, 1 hour before the IRI and extended hepatectomy, did not prolong survival more than 57 and 98 hours, respectively. Simple IPC, 24 hours before IRI and extended hepatectomy had the lowest possible survival (16.7%).Conclusions: Hepatic steatosis and IRI after major liver surgery largely affect morbidity and mortality. Intermittent IPC, 24 hours before IRI and extensive hepatectomy, presents higher 30-day survival and improved liver function parameters.     

肝缺血再灌注对肝硬化大鼠的损伤作用

目的 研究肝硬化大鼠肝缺血再灌注（hepatic ischemia reperfusion,HIR）损伤的机制和程度。方法 用60％四经碳（CCl4）溶液皮下注射方法制作肝硬化大鼠模型，肝硬化大鼠随机分为六组：A组：假手术组（6只）；B、C、D组：分别为肝门完全阻断20min、30min、40min（每组各16只）；E组“单纯肠系膜上静脉阻断（16只）;F组：肝门阻断＋门腔转流（16只）；另外，随机取10只正常肝脏大鼠组成G组，行肝门完全阻断30min。观察7天存活率、丙氨酸氨基转移酶（ALT）、天门冬氨酸氨基转移酶（AST）、透明质酸（HA）、肿瘤坏死因子（TNF），以及肝、肺病理的变化。结果 B、C、D、E、F、G组的7天存活率分别为10／10只、6／10只、4／10只、5／10只、8／10只、6／10只；再灌注后4h血清TNF变化：后六组均明显高于术前，C、D组高于B、A组，E、F组也明显高于A组（P＜0.01）再灌注4h后HA变化：D组明显高于B、E组，F、C组明显高于A组（P＜0.05）；再灌注4h后D、C组的AST、ALT均明显高于B组、A组、D组的AST明显高于F组，F组的AST、ALT显著高于E组（P＜0.05）；C、G两组比较，上述指标的差异无显著性（P＞0.05）；肝、肺组织学检查可见肝、肺的病理损害，程度随缺血时间的延长而加重，E组损伤重于F组。结论 硬化肝脏肝缺血再灌注损伤涉及全身多个器官，门脉静淤血可能是损伤乃至死亡的主要原因；肝硬化大鼠耐受肝缺血的最大的时限在30min以内。     

Contribution of endothelin-1 to microcirculatory impairment in total hepatic ischemia and reperfusion injury

BACKGROUND: Endothelin (ET)-1 may have a role in hepatic polymorphonuclear leukocyte infiltration as well as microcirculatory disturbance during hepatic ischemia-reperfusion (HIR) injury. This study was conducted to investigate the influence of ET-1 on the hepatic microcirculation after total HIR and to evaluate the effect of a nonselective ET receptor antagonist under these conditions. METHODS: Male rats pretreated with either normal saline (NS group) or TAK-044, a nonselective ET receptor antagonist (TAK group), were subjected to 120 min of total hepatic ischemia with extracorporeal portosystemic shunting. RESULTS: Plasma ET-1 levels increased significantly from 1 to 6 hr after reperfusion in the NS group when compared with the nonischemic control. In the early phase of reperfusion, the NS group showed significantly narrower sinusoids, lower hepatic tissue blood flow, a lower hepatic tissue oxy-hemoglobin concentration, and more hepatic neutrophil infiltration than the TAK group (P<0.05). Pretreatment with TAK-044 improved hepatic microcirculatory derangement, and resulted in significantly better 7-day survival (61.5%) with more bile production after reperfusion when compared with the NS group (P<0.01). CONCLUSIONS: The present study demonstrated that ET-1 is involved in the development of HIR injury by causing deterioration of the hepatic microcirculation. A nonselective ET receptor antagonist successfully ameliorated HIR injury through improvement of hepatic oxygenation and of the microcirculation along with reduced hepatic neutrophil infiltration.     

Beneficial effect of deletion variant of hepatocyte growth factor for impaired hepatic regeneration in the ischemically damaged liver

This study was conducted to determine the influence of hepatic ischemia and reperfusion (HIR) injury on liver regeneration and the effect of the deletion variant of hepatocyte growth factor (dHGF) under these conditions. Male Sprague-Dawley rats were subjected to 60 minutes of total hepatic ischemia, and two-thirds hepatectomy was performed just before reperfusion. Animals received intravenous administration of either vehicle buffer (vehicle control group) or dHGF (1 mg/kg) (HGF group) at the end of the period of hepatic ischemia and again 6 hours after reperfusion. At 8 hours after hepatectomy, plasma HGF levels in the vehicle control group were significantly lower than those in the nonischemic controls. Plasma aspartate transaminase levels in the vehicle control group reached 3,462 +/- 1,039 IU/L, but levels in the HGF group were significantly inhibited to 1,849 +/- 605 IU/L. The relative liver weight in the vehicle control group was significantly greater than in the HGF group, a finding that was implicated in focal liver necrosis with sinusoidal congestion. Less histological damage was observed in the HGF group. Twenty-four hours after hepatectomy, an increase in the relative liver weight in nonischemic controls and in the HGF group was higher than that in vehicle control group, and the 5-bromo-2?deoxyuridine (BrdU) labeling index in the HGF group was 23% versus 18% in the nonischemic controls. Administration of dHGF significantly improved the 7-day survival to 82% versus 40% in the vehicle control group. dHGF has potential benefit as a pharmacological agent to ameliorate impairment of the hepatic microcirculation and to potentiate a regeneration response in the ischemically damaged liver after hepatectomy and/or liver transplantation.     

两种入肝血流阻断方式对硬化肝脏再灌注损伤的比较研究

目的:比较保留肝动脉持续门静脉阻断方式与间断肝门阻断方式对硬化肝脏的再灌注损伤。方法:四氯化碳诱导肝硬化大鼠随机分为3组:假手术对照组(SO);保留肝动脉持续门静脉阻断组(PVC);间断肝门阻断组(IC)。分别检测肝脏血流阻断45 min后复流1、6、24 h血清AST含量,行肝血流复流后吲哚青绿15 min滞留试验(ICGR15)及行组织形态学、超微结构观察。结果:肝血流复流1、6、24 h PVC组和IC组血清AST分别为607±322、791±119、375±136 IU/L和547±273、864±241、449±131IU/L,均高于SO组的188±52IU/L,3组比较差异有统计学意义(F=6.81,44.03,11.38;P<0.05),PVC组和IC组差异无统计学意义。肝血流复流1、6、24 h,PVC组及IC组ICGR15分别为(23±9)%、(19±6)%、(18±3)%和(54±9)%、(38±6)%、(29±3)%,均高于SO组的(16±4)%、(14±3)%、(15±3)%,3组比较差异有统计学意义(F=57.84,42.41,37.15;P<0.05),其中IC组最高。病理组织学检查示PVC组及IC组肝血流复流后肝组织发生点状及小片状坏死,两组间病变程度相似;超微结构显示IC组较PVC组线粒体数目增多、肿胀,部分线粒体破裂溶解。结论:与间断肝门阻断方式相比,保留肝动脉持续门静脉阻断方式对硬化肝脏功能影响更小,具有较好的临床应用前景。     

缺血预处理减轻大鼠肝缺血再灌注损伤的免疫机制研究

目的探讨大鼠肝缺血再灌注损伤(HIRI)的免疫机制和缺血预处理(IPC)的保护作用。 方法80只大鼠被随机分为假手术组(A组)、肝门阻断20 min组(B组)、30 min组(C组)、40 min组(D组)以及肝门阻断30 min前预处理组(E组),每组再分为再灌注2 h亚组和24 h亚组,各8只。检测再灌注后2 h、24 h的血丙氨酸转氨酶(ALT)、天冬氨酸转氨酶(AST)、白细胞介素10、12(IL-10、IL-12)以及外周血T淋巴细胞亚群的水平,观察再灌注后2 h、24 h时的存活率及肝脏病理情况。 结果随着肝门阻断时间的延长,ALT、AST显著升高,肝内炎症细胞浸润增加,24 h存活率逐渐降低。D组再灌注2 h时,CD8+ T淋巴细胞显著升高,CD4+/CD8+比值下降,调节性T淋巴细胞显著减少,血清IL-10显著降低,而IL-12水平显著升高。再灌注后24 h,B组大鼠各项指标逐步恢复至假手术组水平,而D组大鼠CD4+T淋巴细胞、CD4+/CD8+比值尤其是Treg显著升高,且IL-10水平显著升高,IL-12水平明显降低。与C组相比,E组阻断30 min后无一例死亡,再灌注2 h的ALT、AST水平显著降低,Treg和IL-10水平显著升高,IL-12水平明显降低,再灌注24 h后各项指标恢复并接近假手术组水平,肝脏病理损伤较轻。 结论肝缺血再灌注引起肝脏损伤甚至死亡,可能与诱导T淋巴细胞尤其是Treg和细胞因子的紊乱有关。缺血预处理可以增加再灌注早期的Treg细胞,有效纠正免疫紊乱,减轻损伤。     

不同时限缺血预处理对硬化肝脏保护作用的实验研究

目的: 探讨缺血预处理对硬化肝脏缺血再灌注的作用,并寻找一种有效缺血预处理的时间窗和理想方案. 方法: 将64只雄性、肝硬化SD大鼠随机分为八组,每组八只:假手术组(SO组);缺血再灌注组(I/R组);缺血预处理1、2、3、4、5和6组(IPC1、IPC2、IPC3、IPC4、IPC5和IPC6).以肝组织ATP、ADP、AMP及EC(用高效液相色谱法测定),血清ALT、AST、LDH(用全自动生化仪测定)和肝脏胆汁分泌量来评价肝功能. 结果: 再灌注末,IPC3组、IPC4组、IPC5组ATP含量均明显高于I/R组(P分别为0.01、0.07和0.000);同样,测定EC时发现,IPC3组、IPC4组和IPC5组均明显高于I/R组(P=0.000).与I/R组比较,IPC4组和IPC5组的血清ALT差异有显著性(P分别为0.013和0.000);其血清LDH差异亦有显著性(P=0.023,P=0.000),而血清AST却只有IPC5组显著低于I/R组(P=0.001).IPC3组、IPC4组和IPC5组肝脏的胆汁分泌量明显高于I/R组(P=0.028,P=0.023,P=0.008). 结论: 5~10min予一次或两次缺血预处理,能启动IPC对肝硬化大鼠肝脏I/R损伤的保护作用;10 min的缺血预处理,对肝硬化大鼠肝脏I/R损伤的保护作用最强.     

Protective effect of ischemic preconditioning against intermittent warm-ischemia-induced liver injury

BACKGROUND: Although ischemic preconditioning (IPC) has been reported to protect the liver from injury when subjected to continuous hepatic ischemia, whether IPC protects rat livers against ischemia-reperfusion (I/R) injury after intermittent ischemia has not been elucidated. MATERIALS AND METHODS: Five groups of Wistar rats were subjected to intermittent hepatic ischemia (I) comprising 15-min ischemia and 5-min reperfusion three times with or without prior IPC (10-min ischemia and 10-min reperfusion), 45-min continuous ischemia (C) with or without IPC, and sham operation. Serum transaminase and lactic acid levels, hepatic tissue energy charges, and hepatic blood perfusion were measured after reperfusion. Plasma tumor necrosis factor-alpha (TNF-alpha) levels were determined after reperfusion for 120 min. Histological and apoptotic findings were evaluated after reperfusion for 180 min. RESULTS: IPC significantly reduced serum transaminase levels after continuous and intermittent ischemia (IPC + C, 1107 vs C, 2684 IU/l; IPC + I, 708 vs I, 1859 IU/l). After hepatic ischemia without IPC, apoptosis and necrosis with increased plasma TNF-alpha levels were observed. IPC protected livers from injury by interfering with the increase in plasma TNF-alpha (IPC + I, 27.6 vs I, 64.8 pg/ml; IPC + C, 21.6 vs C, 49.3 pg/ml). This resulted in the attenuation of hepatic necrosis after continuous ischemia and significantly reduced necrosis and apoptosis after intermittent ischemia. CONCLUSIONS: IPC exerts a greater protective effect against hepatic I/R injury after intermittent hepatic ischemia than after continuous hepatic ischemia.     

肝细胞凋亡在肝硬化大鼠肝缺血再灌注损伤中的意义

目的 研究肝硬化大鼠肝缺血再灌注（I／R）损伤和硬化肝比正常肝更容易损伤的机制是否与肝细胞凋亡有关？方法 建立原位肝I／R模型，将肝硬化大鼠随机分为2组：A组：缺血时间（I）＝20min;B组：I＝30min;C组：正常大鼠，I＝30min，比较灌注前后各组血清AST、ALT的变化和肝细胞凋亡的百分数。结果 肝硬化大鼠肝I／R后，AST、ALT明显升高，以灌注后6h为高峰，灌注24、72h后逐渐下降。灌注6h后，B组的血清转氨酶为3组中最高（P＜0．05），说明B组肝损伤最严重。肝细胞凋亡在I／R后明显增多，以灌注后6h为高峰，随后逐渐下降，变化与转氨酶一致。灌注后6h，B、A、C组肝细胞凋亡的百分数分别为20．9％、13．5％和10．7％，B组明显高于A、C两组（P＜0．01）。再灌注72h内未见明显肝细胞坏死。结论 肝细胞凋亡是肝硬化大鼠I／R损伤肝细胞死亡的主要形式，肝细胞凋亡与肝缺血时间密切相关，肝硬化肝细胞比正常肝细胞容易发生凋亡是硬化肝对缺血敏感的重要原因。     

Advantage of ischemic preconditioning for hepatic resection in pigs

BACKGROUND: Ischemic preconditioning (IP) and intermittent inflow occlusion (IO) have provided beneficial outcomes in hepatic resection. However, comparison of these two procedures against warm hepatic ischemia-reperfusion injury has not been studied enough. MATERIALS AND METHODS: Pigs that had undergone 65% hepatectomy were subjected to Control (120 min continuous ischemia, n = 6), IP (10 min ischemia and 10 min reperfusion, followed by 120 min continuous ischemia, n = 6), and IO (120 min ischemia in the form of eight successive periods of 15 min ischemia and 5 min reperfusion, n = 6). We evaluated hepatocyte injury by aspartate aminotransferase, lactate dehydrogenase and hepaplastin test, hepatic microcirculation by hepatic tissue blood flow (HTBF) and endothelin (ET)-1, inflammatory response by tumor necrosis factor-alpha (TNF-alpha), and histopathology after reperfusion. RESULTS: IP prevented hepatocyte injury, HTBF disturbance, and hepatocyte necrosis in histopathology as well as IO. These two groups showed significantly better outcomes than Control. IP produced significantly less ET-1 and TNF-alpha than IO. CONCLUSIONS: IP ameliorated hepatic warm ischemia-reperfusion injury. Furthermore, IP gained more advantages in preventing chemokine production such as ET-1 and inflammatory response over IO. IP could take the place of IO for hepatectomy.     

FTY720 Attenuates Hepatic Ischemia-Reperfusion Injury in Normal and Cirrhotic Livers

Hepatic ischemia-reperfusion injury is an inevitable consequence during liver surgery. The outcome is particularly poor in cirrhotic livers, which are more prone to hepatic ischemia-reperfusion injury. We aim to study whether FTY720 could attenuate hepatic ischemia-reperfusion injury both in normal and in cirrhotic livers. We applied a 70% liver-ischemia (60 min) model in rats with normal or cirrhotic livers. FTY720 was given 20 min before ischemia and 10 min before reperfusion (1 mg/kg, i.v.). Liver tissues and blood were sampled at 20 min, 60 min, 90 min, 6 h and 24 h after reperfusion for detection of MAPK-Egr-1, Akt pathways and caspase cascade. Hepatic ultrastructure and apoptosis were also compared. FTY720 significantly improved liver function in the rats with normal and cirrhotic livers. Akt pathway was activated at 6 and 24 h after reperfusion. FTY720 significantly down-regulated Egr-1, ET-1, iNOS and MIP-2 accompanied with up-regulation of A20, IL-10, HO-1 and Hsp70. MAPK (Raf-MEK-Erk) pathway was down-regulated. Hepatic ultrastructure was well maintained and fewer apoptotic liver cells were found in the FTY720 groups. In conclusion, FTY720 attenuates ischemia-reperfusion injury in both normal and cirrhotic livers by activation of cell survival Akt signaling and down-regulation of Egr-1 via Raf-MEK-Erk pathway.     

白术多糖预处理对大鼠肝脏缺血再灌注损伤的实验研究

目的:研究白术多糖(AMP)对大鼠肝脏缺血再灌注损伤的影响及作用机制。方法:将72只成年雄性SD大鼠随机分成3组:假手术组(Sham组)、缺血再灌注组(HIRI组)、AMP预处理缺血再灌注组(AMP组)。缺血60 min后分别再灌注1、6、24 h后取材,测定血清谷丙转氨酶(ALT)、谷草转氨酶(AST)及一氧化氮(NO)、内皮素(ET-1)水平,光镜及透射电镜下观察各组肝细胞的显微结构及超微结构变化。结果:AMP组及HIRI组ALT、AST水平均高于Sham组;与HIRI组比较,AMP组ALT、AST水平显著降低(P<0.05)。与Sham组比较,HIRI组及AMP组术后各时段的NO水平均明显降低,ET-1水平明显升高,术后6 h时明显(P<0.05);与HIRI组相比较,AMP组术后各时段NO水平升高,而ET-1水平降低,差异有统计学意义(P<0.05)。光镜下HIRI组大鼠肝细胞肿胀、变性坏死,肝血窦变窄、淤血及炎性细胞浸润等,而AMP组明显好转。电镜下HIRI组大鼠肝细胞线粒体细胞核皱缩变形,染色质粗糙,核仁浓缩甚至裂解,部分膜破裂,线粒体嵴疏松溶解等,而AMP组明显好转。结论:AMP可以提高缺血再灌注大鼠体内NO水平,同时降低ET-1水平,改善肝脏微循环障碍,对肝脏起保护作用。     

Gadolinium pretreatment decreases survival and impairs liver regeneration after partial hepatectomy under ischemia/reperfusion in rats

BACKGROUND: Modulation of Kupffer cell functions by treatment with gadolinium chloride protects the liver against reperfusion injury. However, its effect on liver regeneration after hepatectomy under ischemia/reperfusion has not been studied. Using a common clinical ischemia/reperfusion technique, we examined the effect of gadolinium on liver regeneration after hepatectomy in rats. METHODS: After an initial 15-minute ischemia and 15-minute reperfusion, 70% hepatectomy was performed during the second 15-minute ischemia period in gadolinium-pretreated (gadolinium group) and saline solution--pretreated (control group) rats. The 24-hour survival rate, relative liver weight, DNA synthesis rate, and hepatic adenosine triphosphate level were examined immediately after hepatectomy and on postoperative days (PODs) 1, 2, 3, and 7. Serum levels of total bilirubin, glutamic pyruvic transaminase, and endotoxin were also measured. RESULTS: The 24-hour survival rate was significantly lower in the gadolinium group (67%) than in the control group (100%). On POD 1, the relative liver weight and DNA synthesis rate were significantly lower in the gadolinium group than in the control group. On POD 1, serum total bilirubin and endotoxin levels were significantly higher in the gadolinium group than in the control group. Immediately after hepatectomy, the hepatic adenosine triphosphate level was significantly lower in the gadolinium group than in the control group. CONCLUSIONS: Under ischemia/reperfusion, gadolinium pretreatment impairs liver regeneration and energy status after hepatectomy and decreases postoperative survival.     

Pentoxifylline contributes to the hepatic cytoprotective process in rats undergoing hepatic ischemia and reperfusion injury.

AIM: Considerable efforts have been made to find and/or eliminate the underyling causes of hepatic ischemia-reperfusion injury, but many points are still unclear. Pentoxifylline-related cytoprotection is one of these unclear points. Our study tests the effects of pentoxifylline on the hepatic cytoprotective process in an experimental model. MATERIALS AND METHODS: The animals were divided into two groups: (1) placebo-pretreated rats and (2) pentoxifylline-pretreated rats. After pretreatment, all rats underwent the hepatic ischemia-reperfusion procedure which was performed by clamping the hepatoduodenal ligament. To evaluate the liver injury, serum levels of alanine transaminase (ALT) and aspartate transaminase (AST), and liver tissue levels of prostaglandin E(2) (PGE(2)) were measured before ischemia, immediately after ischemia and immediately after reperfusion. RESULTS: Before ischemia and immediately after ischemia, there were no significant differences between ALT and AST levels of groups 1 and 2 (p >0.05). However, at the end of reperfusion, ALT and AST levels of group 2 were significantly decreased when compared with group 1 (p < 0.05 and p < 0.01, respectively). Additionally, tissue levels of PGE(2) that were obtained before ischemia, immediately after ischemia and immediately after reperfusion in group 2 were significantly higher than those of group 1 (p < 0.001). CONCLUSION: Pentoxifylline reduces reperfusion injury of the liver through significantly decreased transaminase levels, and contributes to hepatic cytoprotection by increasing tissue levels of PGE(2) significantly. These effects reflect the role of tissue PGE(2) in pentoxifylline-related hepatoprotection against ischemia-reperfusion injury of the liver.     

Effects of ischemic preconditioning on regenerative capacity of hepatocyte in the ischemically damaged rat livers

BACKGROUND: Liver regeneration after partial hepatectomy is regulated by several factors that activate or inhibit hepatocyte proliferation. A short period of ischemia-reperfusion (IR), called ischemic preconditioning (IPC), protects the liver against subsequent sustained ischemic insults. The present study investigated the effects of IPC on liver regeneration after partial hepatectomy under IR in rats. MATERIALS AND METHODS: Male Wistar rats were subjected to 45 min of total hepatic ischemia, and 70% hepatectomy was performed just before reperfusion. Animals were pre-treated with either IPC (10/15 min) (IPC + PHx group) or not (ischemia + PHx). The survival rate, serum transaminases, tumor necrosis factor (TNF)-alpha, and interleukin (IL)-6 levels, hepatocyte proliferation and histological change of the remnant liver were measured in both groups and compared with non-ischemic controls subjected to 70% hepatectomy alone (PHx group). RESULTS: The survival rate was significantly better in the IPC + PHx group than in the ischemia + PHx group. Furthermore, IPC reduced liver injury determined by liver histology and serum transaminases. There was an early rise in serum TNF-alpha and IL-6 levels in the ischemia + PHx group. Compared with non-ischemic controls, IPC significantly decreased TNF-alpha, but not IL-6 during the late (24 and 48 h) phases of reperfusion. Rats subjected to 70% hepatectomy and 45 min of hepatic ischemia showed significantly reduced hepatocyte proliferation (mitotic index, proliferating cell nuclear antigen, and relative liver weight) when compared with animals subjected to hepatectomy alone. However, hepatocyte proliferation was markedly increased in rats pretreatment with IPC when compared with ischemic controls. CONCLUSION: These results suggest that ischemic pre-conditioning ameliorates the hepatic injury associated with ischemia-reperfusion and has a stimulatory effect on liver cell regeneration that may make it valuable as a hepatoprotective modality. Il-6 appears to be key mediator in promoting regeneration after combined ischemia and hepatic resection.     

Evaluation of a protease inhibitor in the prevention of ischemia and reperfusion injury in hepatectomy under intermittent Pringle maneuver

BACKGROUND: The severity of ischemia and reperfusion (I/R) injury is an important determinant of patient outcome in hepatic surgery. The aim of this study was to investigate the efficacy of a protease inhibitor in alleviating I/R injury to human liver in the setting of hepatectomy under intermittent Pringle maneuver. METHODS: Sixty patients who underwent liver resection under conditions of intermittent inflow occlusion were randomly assigned to 2 groups (n = 30 each) according to the use of a synthetic protease inhibitor (gabexate mesilate or GM). GM was administered intravenously at a dosage of 2.0 mg/kg/h starting 12 hours before surgery until postoperative day 2. Preoperative and intraoperative clinical variables and postoperative outcomes were evaluated. The plasma levels of a cytokine, interleukin (IL)-6, as well as laboratory biochemical liver function parameters were analyzed to evaluate hepatic I/R injury. RESULTS: The 2 groups of patients were comparable with regard to hepatic inflow occlusion time, extent of liver resection, and background liver histology. The preoperative administration of GM (GM group) substantially alleviated hepatic I/R injury compared with the untreated control group; postoperative serum transaminase levels were significantly decreased in association with marked suppression of IL-6 levels in blood circulation during surgery. This was accompanied by a lower incidence of postoperative complications. The patients without postoperative complications had significantly lower activities of plasma IL-6 at 24 hours after surgery. CONCLUSIONS: This prospective randomized study demonstrated the hepatoprotective effect of a synthetic protease inhibitor in the setting of hepatectomy under the intermittent Pringle maneuver.     

常温下一次性和间断肝门阻断对肝损伤的对比研究及还原型谷胱甘肽的保护作用

目的 对比常温下一次性和间断人肝血流阻断法所致肝损伤,并探讨还原型谷胱甘肽的保护作用。方法 SD大鼠32只,按人肝血流阻断方式及是否应用还原型谷胱甘肽(GSH)分为4组,即一次性阻断加和不加GSH(CP和CA)组及间断阻断加和不加GSH(IP和IA)组,每组8只。CP和CA组持续阻断肝门40min,IP和IA组阻断2个20min并间隔5min,再灌注时间为60min。观察指标为肝组织丙二醛(MDA)和铜/锌超氧化物歧化酶(Cu/Zn SOD)含量,血ALT和AST活性及肝组织光镜和电镜观察。结果 组内比较,阻断后血ALT及AST活性较阻断前明显增高,差异有显著意义(P<0.05),MDA和Cu/zn SOD含量则无显著性差异(P>0.05)。再灌注后各值较阻断前均有显著性差异(P<0.05)。组间比较,CP与IP及CA与IA组间各观察值差异均无显著意义(P>0.05)。而再灌注后CP与CA组、IP和IA组比较均有显著性差异(P<0.05)。形态学上,各组阻断后均有细胞损伤表现,再灌注后有所恢复,其中CP和IP组肝细胞结构基本恢复正常,而CA和IA组仍有部分细胞呈空泡变性。各组各时点均未出现不可复性损伤。结论 常温下一次性和间断阻断肝门40min均可导致可复性肝损伤,其程度无明显差异。此时限内一次性阻断是肝切除术中适宜的阻断方法。术中应用GSH对其有明显的对抗作用,可能成为一种新的保护方法。     

High expression of the CD14 gene and interleukin-1beta gene in the liver and lungs of cirrhotic rats after partial hepatectomy

BACKGROUND: A hepatic resection is invasive for cirrhotic patients because postoperative complications, such as hepatic disturbance sometimes resulting in hepatic failure and pulmonary disturbances, are frequent and serious. We investigated here the alteration of the CD14 and inflammatory cytokine genes expressed in the liver and lungs after partial hepatectomy (PH) of a cirrhotic rat model to help elucidate the pathophysiological change occurring during the postoperative course of hepatectomized cirrhotic patients. MATERIALS AND METHODS: Wistar rats were orally administrated carbon tetrachloride once a week for 14 weeks to induce liver cirrhosis. In comparison with cirrhotic and normal rats, we analyzed the expression of the CD14, tumor necrosis factor-alpha, and interleukin (IL)-1beta genes in remnant liver and whole lung tissue during 48 h after 30% partial hepatectomy with Northern blottings and measured asparatate aminotransferase (AST) in serum for evaluation of postoperative hepatic injury. Gadolinium chloride (GdCl3; 7 mg/kg body weight) was intravenously injected 24 h before partial hepatectomy to suppress Kupffer cells (KC) activation. RESULTS: The expression of the CD14 and IL-1beta genes moderately increased at 6 h and peaked at 12 h in parallel with the time course of AST values after PH only in cirrhotic rats. GdCl(3) significantly inhibited the elevation of AST similar to the inhibition of the expression of the CD14 and IL-1beta genes after PH. In addition, the expression of these genes showed marked enhancement in the lungs of the cirrhotic hepatectomy model. CONCLUSIONS: KC activation was responsible for hepatic injury after PH, and the CD14 system appeared to be an early trigger for KC activation followed by induction of inflammatory cytokine IL-1beta synthesis leading to hepatic injury. Furthermore, the CD14 system was suggested to participate in respiratory disturbances after hepatectomy in cirrhosis.     

Ischemic injury in cirrhotic livers: an experimental study of the temporary arrest of hepatic circulation.

In order to prevent massive bleeding at hepatectomy, the temporary arrest of hepatic circulation is often performed but it is not clear whether this arrest of circulation is tolerated equally by the cirrhotic liver and the normal liver. We investigated biochemically the detailed effects of ischemia on cirrhotic livers in rats with experimentally induced liver cirrhosis. Thioacetoamide was used to prepare the rat cirrhotic liver model (LC group, n = 6). After laparotomy, the vessels to the left lateral lobe were clamped for 30 min and then declamped. Changes in AST isozymes and the aminogram in the blood were examined after ischemia. Postischemic changes in hepatic adenine nucleotides (AdN) and the brain aminogram were also examined. These were compared with those of normal liver ischemia (N group, n = 6) at 24 hr after recirculation. In the LC group, serum levels of mitochondrial AST, a parameter of necrotic cells, were significantly higher than those of the N group. Hepatic AdN levels decreased to 60.6% of the original levels after ischemic injury but those of the N group remained at 95.4% of the original level. Since AdN in tissue is accepted as a reliable parameter of viable cells, cirrhotic livers subjected to ischemia might have more necrotic cells than normal livers. Sequential analysis of serum aminograms of the LC group after ischemia revealed that the ratio of Val+Leu+Ileu/Tyr+Phe decreased to near 1.0 but that of the N group always remained higher than 3.0. Based on these results, it was concluded that ischemic injury in cirrhotic livers is more hazardous than that in normal livers.