Hepatic ischemic preconditioning increases portal vein flow in experimental liver ischemia reperfusion injury

BACKGROUND: Ischemic preconditioning(IPC) has been shown to decrease liver injury and to increase hepatic microvascular perfusion after liver ischemia reperfusion. This study aimed to evaluate the effects of IPC on hemodynamics of the portal venous system. METHODS: Thirty-two rats were randomized into two groups: IPC group and control group. The rats of the IPC group underwent IPC by 10 minutes of liver ischemia followed by 10 minutes of reperfusion before liver ischemia, and the rats of the control group were subjected to 60 minutes of partial liver ischemia. Non-ischemic lobes were resected immediately after reperfusion. The animals were studied at 4 hours and 12 hours after reperfusion. Mean arterial pressure, heart rate, portal vein flow and pressure were analyzed. Blood was collected for the determination of the levels of aspartate aminotransferase, alanine aminotransferase, calcium, lactate, pH, bicarbonate, and base excess. RESULTS: IPC increased the mean portal vein flow at 4 hours and 12 hours after reperfusion. IPC recovered 78% of the meanportal vein flow at 12 hours after reperfusion. IPC decreased the levels of aspartate aminotransferase, alanine aminotransferase and lactate, and increased the levels of ionized calcium, bicarbonate and base excess at 12 hours after reperfusion. CONCLUSIONS: This study demonstrated that IPC increases portal vein flow and enhances hepatoprotective effects in liver ischemia reperfusion. The better recovery of portal vein flow after IPC may be correlated with the lower levels of transaminases and with the better metabolic profile.

Conventional, but not remote ischemic preconditioning, reduces iNOS transcription in liver ischemia/reperfusion

AIM:To study the effects of preconditioning on inducible nitric oxide synthase(iNOS)and interleukin 1(IL-1)receptor transcription in rat liver ischemia/reperfusion injury(IRI).METHODS:Seventy-two male rats were randomized into 3 groups:the one-hour segmental ischemia(IRI,n=24)group,the ischemic preconditioning(IPC,n=24)group or the remote ischemic preconditioning(RIPC,n=24)group.The IPC and R-IPC were performed as 10 min of ischemia and 10 min of reperfusion.The iNOS and the IL-1 receptor mRNA in the liver tissue was analyzed with real time PCR.The total Nitrite and Nitrate(NOx)in continuously sampled microdialysate(MD)from the liver was analyzed.In addition,the NOx levels in the serum were analyzed.RESULTS:After 4 h of reperfusion,the iNOS mRNA was significantly higher in the R-IPC(ΔCt:3.44±0.57)group than in the IPC(ΔCt:5.86±0.82)group(P=0.025).The IL-1 receptor transcription activity was reduced in the IPC group(ΔCt:1.88±0.53 to 4.81±0.21),but not in the R-IPC group,during reperfusion(P=0.027).In the MD,a significant drop in the NOx levels was noted in the R-IPC group(12.3±2.2 to 4.7±1.2μmol/L)at the end of ischemia compared with the levels in early ischemia(P=0.008).A similar trend was observed in the IPC group(11.8±2.1 to 6.4±1.5μmol/L),although this difference was not statistically significant.The levels of NOx rose quickly during reperfusion in both groups.CONCLUSION:IPC,but not R-IPC,reduces iNOS and IL-1 receptor transcription during early reperfusion,indicating a lower inflammatory reaction.NOx is consumed in the ischemic liver lobe.

Identification of differentially expressed genes after partial rat liver ischemia/reperfusion by suppression subtractive hybridization

AIM: To identify potential diagnostic target genes in early reperfusion periods following warm liver ischemia before irreversible liver damage occurs. METHODS: We used two strategies (SSH suppression subtractive hybridization and hybridization of cDNA arrays) to determine early changes in gene expression profiles in a rat model of partial WI/R, comparing postischemic and adjacent nonischemic liver lobes. Differential gene expression was verified (WI/R; 1 h/2 h) and analyzed in more detail after warm ischemia (1 h) in a reperfusion time kinetics (0, 1, 2 and 6 h) and compared to untreated livers by Northern blot hybridizations. Protein expression was examined on Western blots and by immunohistochemistry for four differentially expressed target genes (Hsp70, Hsp27, Gadd45a and IL-1rI). RESULTS: Thirty-two individual WI/R target genes showing altered RNA levels after confirmation by Northern blot analyzes were identified. Among them, six functionally uncharacteristic expressed sequences and 26 known genes (12 induced in postischemic liver lobes, 14 with higher transcriptional expression in adjacent nonischemic liver lobes). Functional categories of the verified marker genes indicate on the one hand cellular stress and tissue damage but otherwise activation of protective cellular reactions (AP-1 transcription factors, apoptosis related genes, heat shock genes). In order to assign the transcriptional status to the biological relevant protein level we demonstrated that Hsp70, Hsp27, Gadd45a and IL-1rI were clearly up-regulated comparing postischemic and untreated rat livers, suggesting their involvement in the WI/R context. CONCLUSION: This study unveils a WI/R response gene set that will help to explore molecular pathways involved in the tissue damage after WI/R. In addition, these genes especially Hsp70 and Gadd45a might represent promising new candidates indicating WI/R liver damage.

Beneficial effects of adenosine triphosphate-sensitive K^+ channel opener on liver ischemia/reperfusion injury

AIM: To investigate the effect of diazoxide administration on liver ischemia/reperfusion injury.

Portal Gas Embolism with Acute Liver Ischemia： Case Report

Portal gas embolism is a rare entity and considered a sign of poor prognosis in abdominal diseases, its mortality rate is about 75%. This case report is about a 61-year old patient with portal gas embolism and acute liver ischemia, evolving to death within 24 hours. Some cases reported in the literature demonstrate the severity of this dramatic condition. It is necessary to have a higher level of suspicion in the vascular structures of the abdomen in order to allow a timely treatment.

Molecular mechanisms of liver ischemia reperfusion injury:Insights from transgenic knockout models

Ischemia reperfusion injury is a major obstacle in liver resection and liver transplantation surgery.Understanding the mechanisms of liver ischemia reperfusion injury(IRI) and developing strategies to counteract this injury will therefore reduce acute complications in hepatic resection and transplantation,as well as expanding the potential pool of usable donor grafts.The initial liver injury is initiated by reactive oxygen species which cause direct cellular injury and also activate a cascade of molecular mediators leading to microvascular changes,increased apoptosis and acute inflammatory changes with increased hepatocyte necrosis.Some adaptive pathways are activated during reperfusion that reduce the reperfusion injury.IRI involves a complex interplay between neutrophils,natural killer T-cells cells,CD4+ T cell subtypes,cytokines,nitric oxide synthases,haem oxygenase-1,survival kinases such as the signal transducer and activator of transcription,Phosphatidylinositol 3-kinases/Akt and nuclear factor κβ pathways.Transgenic animals,particularly genetic knockout models,have become a powerful tool at elucidating mechanisms of liver ischaemia reperfusion injury and are complementary to pharmacological studies.Targeted disruption of the protein at the genetic level is more specific and maintained than pharmacological inhibitors or stimulants of the same protein.This article reviews the evidence from knockout models of liver IRI about the cellular and molecular mechanisms underlying liver IRI.

Melatonin abates liver ischemia/reperfusion injury by improving the balance between nitric oxide and endothelin

BACKGROUND: Melatonin exerts complex physiological and pharmacological effects on multiple systems and organs. We hypothesized that melatonin might abate ischemia/ reperfusion (I/R) injury in the liver by inhibiting excessive oxidative stress and keeping nitric oxide (NO) from being scavenged by free radicals. The aim of the present study was to investigate whether melatonin protects the liver from I/R injury and, if so, by what underlying mechanism. METHODS: Under anesthesia, Wistar rats were intraperi- toneally injected with 20 mg/kg melatonin (dissolved in physiological saline containing 4% ethanol, Mel group), 4% alcohol (Alc group), or physiological saline (NS group). The artery, portal vein and bile duct of the left lobe of the liver were clamped for 60 minutes and then released. At different time points after I/R, the rats were sacrificed and blood samples were collected to measure the levels of serum alanine aminotransferase (ALT), lactic dehydrogenase (LDH), and NO. Hepatic tissue samples were collected for measuring endothelin expression by immunohistochemical staining and for routine morphological and histological examination. RESULTS: The levels of both ALT and LDH in the Mel group were significantly reduced for up to 24 hours after I/R compared with the Alc and NS groups (P<0.05). The levels of NO in the Mel group were significantly elevated for up to 12 hours after I/R relative to the NS group (P<0.05). The NO levels were also elevated at 0.5 and 6 hours after I/R in the Alc group (P<0.05). The immunohistochemical staining of hepatic tissue showedthat endothelin-positive cells were significantly fewer in the Mel group than in the Alc and NS groups at 6 hours after I/R (P<0.01). The necrosis of hepatocytes and the destruction of hepatic cords in the Alc and NS groups were greatly improved in Mel-treated rats, which is in concert with our functional data. CONCLUSIONS: Pretreatment with melatonin increased NO bioavailability and decreased endothelin expression, and consequently played a protective role in preserving both liver function and structure during ischemia and reperfusion injury.

Oleanolic acid attenuates liver ischemia reper-fusion injury by HO-1/Sesn2 signaling pathway

BACKGROUND: Ischemia reperfusion injury (IRI) is unavoid-able in liver transplantation and hepatectomy. The present study aimed to explore the possible mechanism and the effect of oleanolic acid (OA) in hepatic IRI. METHODS: Mice were randomly divided into 6 groups based on different treatment. IRI model: The hepatic artery, portal vein, and bile duct to the left and median liver lobes (70% of the liver) were occluded with an atraumatic bulldog clamp for 90 minutes and then the clamp was removed for reperfusion. The mice were sacriifced 6 hours after reperfusion, and blood and liver tissues were collected. Liver injury was evaluated by biochemical and histopathologic examinations. The expressions of Sesn2, PI3K, Akt and heme oxygenase-1 (HO-1) were mea-sured with quantitative real-time RT-PCR and Western blotting. RESULTS: The serum aminotransferases level and scores of he-patic histology were increased after reperfusion. The increase was attenuated by pretreatment with OA (P<0.01). Compared with the IR group, OA pretreatment signiifcantly up-regulated the expression of Sesn2, PI3K, Akt and HO-1 in IR livers (P<0.05). Administration of zinc protoporphyrin (ZnPP), an inhibitor of HO-1, diminished the OA effect on HO-1 and Sesn2 expressions (P<0.05) and the protective effect of OA on IRI. CONCLUSIONS: Our results demonstrate that OA can attenu-ate hepatic IRI. The protective mechanism may be related to the OA-induced HO-1/Sesn2 signaling pathway.

Remote ischemic preconditioning protects liver ischemia-reperfusion injury by regulating eNOS-NO pathway and liver microRNA expressions in fatty liver rats

BACKGROUND: Ischemic preconditioning (IPC) is a strategy to reduce ischemia-reperfusion (I/R) injury. The protective effect of remote ischemic preconditioning (RIPC) on liver I/R injury is not clear. This study aimed to investigate the roles of RIPC in liver I/R in fatty liver rats and the involvement of endothelial nitric oxide synthase-nitric oxide (eNOS-NO) pathway and microRNA expressions in this process. METHODS: A total of 32 fatty rats were randomly divided into the sham group, I/R group, RIPC group and RIPC+I/R group. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and nitric oxide (NO) were measured. Hematoxylin-eosin staining was used to observe histological changes of liver tissues, TUNEL to detect hepatocyte apoptosis, and immunohistochemistry assay to detect heat shock protein 70 (HSP70) expression. Western blotting was used to detect liver inducible NOS (iNOS) and eNOS protein levels and realtime quantitative polymerase chain reaction to detect miR-34a, miR-122 and miR-27b expressions. RESULTS: Compared with the sham and RIPC groups, serum ALT, AST and iNOS in liver tissue were significantly higher in other two groups, while serum NO and eNOS in liver tissue were lower, and varying degrees of edema, degeneration and inflammatory cell infiltration were found. Cell apoptosis number was slightly lower in the RIPC+I/R group than that in I/R group. Compared with the sham group, HSP70 expressions were significantly increased in other three groups (all P<0.05). Compared with the sham and RIPC groups, elevated miR-34a expressions were found in I/R and RIPC+I/R groups (P<0.05). MiR-122 and miR-27b were found significantly decreased in I/R and RIPC+I/R groups compared with the sham and RIPC groups (all P<0.05). CONCLUSION: RIPC can reduce fatty liver I/R injury by affecting the eNOS-NO pathway and liver microRNA expressions.

Role of NF-kappaB in Liver Ischemia Reperfusion Injury of Rats

To determine the role of NF-kappaB in ischemia reperfusion (I/R) injury of the rat liver, rats underwent partial hepatic ischemia and reperfusion. The left and median lobes of the liver were subjected to ischemia for 90 min followed by reperfusion for defined times. NF-kappaB activity was analyzed by electrophoretic mobility shift assay (EMSA). Semiquantitative reverse-transcriptase polymerase chain reaction was used to analyze TNF-α and ICAM-1 mRNA levels. Results showed during liver I/R injury, NF-kappaB activation was induced in a time dependent manner. NF-kappaB was activated within 1h and 2h after the initiation of reperfusion and decreased after 4 h. Messenger RNA expression of TNF-α and ICAM-1 were increased after the reperfusion of 2 h. It was concluded that during hepatic I/R injury, NF-kappaB was activated and could bind to special sequence in the promoters of budget genes, which can up-regulate the expression of TNF-α and ICAM-1 mRNA to result in ischemia reperfusion injury of the rat liver.

STUDY ON INTERCELLULAR ADHESIONMOLECULE-1 AND P-SELECTIN IN LIVER ISCHEMIA AND REPERFUSION INJURY

Objective To investigate the role of intercellular adhesion molecule-1 (ICAM-1) andP- selectin in hepatic ischemia/reperfusion injury. Methods The relationship between P- selectin as well asICAM- 1 and liver ischemia/reperfusion was studied, using a 60 minutes ischemia - reperfusion rat liver model.The animals were divided into three groups including: the sham group, the ischemic control group receiving onlythe normal saline and the treated group receiving anti-P-selection monoclonal antibody (Mab) at a dose of2mg/kg 15 minutes before reperfusion. The following indexes were analyzed: liver injury tests, liver histotogy,serum enzymes level (AST, ALT), and the levels of ICAM-1 and P-selectin in the blood of rats. ResultsSerum enzymes levels were significantly increased during sixty minutes of left lobar ischemia and reperfusion(saline control), and the increment was significantly inhibited with P- selectin Mab. Liver pathology observed bylight microscopy was greatly ameliorated by Mab. Furthermore, the elevated levels of ICAM- 1 and P- selectinwere found in the blood of ischemia/ reperfusion rats. Concluhon ICAM- 1 and P- selectin contribute tohepatic ischemia / reperfusion injury,and the P - selectin Mab can protect the liver against the injury.

Ankaflavin ameliorates steatotic liver ischemiareperfusion injury in mice

BACKGROUND： It is well-known that steatotic liver is more susceptible to ischemia-reperfusion （I/R） injury during liver transplantation, liver resection and other liver surgeries. The increasing incidence of non-alcoholic fatty liver disease （NAFLD） decreases the availability of liver donors. Although steatotic liver is now accepted as a source of liver for trans- plantation, NAFLD exacerbates the liver injury after liver surgery. The present study was to investigate the protective role of ankaflavin in steatotic liver I/R injury.

Polyethylene glycols: An effective strategy for limiting liver ischemia reperfusion injury

Liver ischemia-reperfusion injury(IRI) is an inherent feature of liver surgery and liver transplantation in which damage to a hypoxic organ(ischemia) is exacerbated following the return of oxygen delivery(reperfusion). IRI is a major cause of primary nonfunction after transplantation and may lead to graft rejection, regardless of immunological considerations. The immediate response involves the disruption of cellular mitochondrial oxidative phosphorylation and the accumulation of metabolic intermediates during the ischemic period, and oxidative stress during blood flow restoration. Moreover, a complex cascade of inflammatory mediators is generated during reperfusion, contributing to the extension of the damage and finally to organ failure. A variety of pharmacological interventions(antioxidants, anticytokines, etc.) have been proposed to alleviate graft injury but their usefulness is limited by the local and specific action of the drugs and by their potential undesirable toxic effects. Polyethylene glycols(PEGs), which are non-toxic water-soluble compounds approved by the FDA, have been widely used as a vehicle or a base in food, cosmetics and pharmaceuticals, and also as adjuvants for ameliorating drug pharmacokinetics. Some PEGs are also currently used as additives in organ preservation solutions prior to transplantation in order to limit the damage associated with cold ischemia reperfusion. More recently, the administration of PEGs of different molecular weights by intravenous injection has emerged as a new therapeutic tool to protect liver grafts from IRI. In this review, we summarize the current knowledge concerning the use of PEGs as a useful target for limiting liver IRI.

Effect of liver regeneration after partial hepatectomy and ischemia-reperfusion on expression of growth factor receptors

AIM： To investigate the effects of experimental partial hepatectomy and normothermic ischemia-reperfusion damage on the time course of the expression of four different growth factor receptors in liver regeneration. This is relevant due to the potential therapeutic use of growth factors in stimulating liver regeneration. METHODS： For partial hepatectomy （PH） 80% of the liver mass was resected in Sprague Dawley rats. Ischemia and reperfusion （I/R） were induced by occlusion of the portal vein and the hepatic artery for 15 min. The epidermal growth factor receptor, hepatic growth factor receptor, fibroblast growth factor receptor and tumour necrosis factor receptor-1 were analysed by immunohistochemistry up to 72 h after injury. Quantitative RT-PCR was performed at the time point of minimal receptor expression （24 h）. RESULTS： In immunohistochemistry, EGFR, HGFR, FGFR and TNFR1 showed biphasic kinetics after partial hepatectomy with a peak up to 12 h, a nadir after 24 h and another weak increase up to 72 h. During liver regeneration, after ischemia and reperfusion, the receptor expression was lower; the nadir at 24 h after reperfusion was the same. To evaluate whether this nadir was caused by a lack of mRNA transcription, or due to a posttranslational regulation, RT-PCR was performed at 24 h and compared to resting liver. In every probe there was specific mRNA for the receptors. EGFR, FGFR and TNFR1 mRNA expression was equal or lower than in resting liver, HGFR expression after I/R was stronger than in the control. CONCLUSION： At least partially due to a post-transcriptional process, there is a nadir in the expression of the analysed receptors 24 h after liver injury. Therefore, a therapeutic use of growth factors to stimulate liverregeneration 24 h after the damage might be not successful.

Reduction of ischemia reperfusion injury after liver resection and hepatic inflow occlusion by α-lipoic acid in humans

AIM： To evaluate the protective effects of preconditioning by α-lipoic acid （LA） in patients undergoing hepatic resection under inflow occlusion of the liver. METHODS： Twenty-four patients undergoing liver resection for various reasons either received 600 mg LA or NaCI 15 min before transection performed under inflow occlusion of the liver. Blood samples and liver wedge biopsy samples were obtained after opening of the abdomen immediately after inflow occlusion of the liver, and 30 min after the end of inflow occlusion of the liver. RESULTS： Serum levels of aspartate transferase and alanine transferase were reduced at all time points in patients who received LA in comparison to those who received NaCL. This was accompanied by reduced histomorphological features of oncosis. We observed TUNEL-positive hepatocytes in the livers of the untreated patients, especially after 30 min of ischemia. LA attenuated this increase of TUNEL-positive hepatocytes. Under preconditioning with LA, ATP content was significantly enhanced after 30 min of ischemia and after 30 min of reperfusion. CONCLUSION： This is the first report on the potential for LA reducing ischemia/reperfusion injury （IRI） of the liver in humans who were undergoing liver surgery. Beside its simple and rapid application, side effects did not occur. LA might therefore represent a new strategy against hepatic IRI in humans.

Steatotic livers are susceptible to normothermic ischemiareperfusion injury from mitochondrial Complex-Ⅰ?dysfunction

AIM: To assess the effects of ischemic preconditioning(IPC, 10-min ischemia/10-min reperfusion) on steatotic liver mitochondrial function after normothermic ischemia-reperfusion injury(IRI).METHODS: Sixty male Sprague-Dawley rats were fed8-wk with either control chow or high-fat/high-sucrose diet inducing > 60% mixed steatosis. Three groups(n = 10/group) for each dietary state were tested:(1) the IRI group underwent 60 min partial hepatic ischemia and 4 h reperfusion;(2) the IPC group underwent IPC prior to same standard IRI; and(3) sham underwent t h e s a m e s u r g e r y w i t h o u t I R I o r I P C. H e p a t i c mitochondrial function was analyzed by oxygraphs. Mitochondrial Complex-Ⅰ, Complex-Ⅱ enzyme activity, serum alanine aminotransferase(ALT), and histological injury were measured.RESULTS: Steatotic-IRI livers had a greater increase in ALT(2476 ± 166 vs 1457 ± 103 IU/L, P < 0.01) and histological injury following IRI compared to the lean liver group. Steatotic-IRI demonstrated lower Complex-Ⅰ?activity at baseline [78.4 ± 2.5 vs 116.4 ± 6.0 nmol/(min.mg protein), P < 0.001] and following IRI [28.0 ± 6.2 vs 104.3 ± 12.6 nmol/(min.mg protein), P < 0.001]. Steatotic-IRI also demonstrated impaired Complex-Ⅰ?function post-IRI compared to the lean liver IRI group. Complex-Ⅱ activity was unaffected by hepatic steatosis or IRI. Lean liver mitochondrial function was unchanged following IRI. IPC normalized ALT and histological injury in steatotic livers but had no effect on overall steatotic liver mitochondrial function or individual mitochondrial complex enzyme activities. CONCLUSION: Warm IRI impairs steatotic liver Complex-Ⅰ?activity and function. The protective effects of IPC in steatotic livers may not be mediated through mitochondria.

Proanthocyanidin Alleviates Liver Ischemia/Reperfusion Injury by Suppressing Autophagy and Apoptosis via the

Background and Aims:Hepatic ischemia-reperfusion injury(IRI)is a common pathophysiological phenomenon in clinical practice,which usually occurs in liver transplantation,liver resection,severe trauma,and hemorrhagic shock.Proanthocyanidin(PC),exerted from various plants with antioxidant,antitumor,and antiaging activity,were administrated in our study to investigate the underlying mechanism of its protective function on IRI.Methods:Two doses of PC(50 mg/kg,100 mg/kg)were given to BALB/c mice by intragastric administration for 7 days before partial(70%)warm IR surgery.Serum and liver tissues were collected 2,8,and 24 h after reperfusion for relevant experiments.Results:The results of transaminase and hematoxylin and eosin staining indicated that PC pretreatment significantly alleviated IRI in mice.Serum total superoxide dismutase increased and malondialde-hyde decreased in PC pretreatment groups.Enzyme-linked immunosorbent assays,western blotting,quantitative real-time polymerase chain reaction,and immunohistochemistry showed that inflammation,apoptosis,and autophagy in PC preprocessing groups were significantly inhibited and were dose-dependent.The protein,mRNA expression,and immunohistochemical staining results of peroxisome proliferator-activated receptor alpha(PPARa)and peroxisome proliferator-activated receptor gamma coactivator 1-alpha(PGC1a)in the PC pretreatment groups were significantly upregulated compared with the IR group in a dose-dependent manner.Conclusions:PC pretreatment suppressed inflammation,apoptosis,and autophagy via the PPAR-α signaling pathway to protect against IRI of the liver in mice.

Nitrite,a novel method to decrease ischemia/reperfusion injury in the rat liver

AIM:To investigate whether nitrite administered prior to ischemia/reperfusion(I/R)reduces liver injury.METHODS:Thirty-six male Sprague-Dawley rats were randomized to 3 groups,including sham operated(n=8),45-min segmental ischemia of the left liver lobe(IR,n=14)and ischemia/reperfusion(I/R)preceded by the administration of 480 nmol of nitrite(n=14).Serum transaminases were measured after 4 h of reperfusion.Liver microdialysate(MD)was sampled in 30-min intervals and analyzed for glucose,lactate,pyruvate and glycerol as well as the total nitrite and nitrate(NOx).The NOx was measured in serum.RESULTS:Aspartate aminotransferase(AST)at the end of reperfusion was higher in the IR group than in the nitrite group(40±6.8μkat/L vs 22±2.6μkat/L,P=0.022).Similarly,alanine aminotransferase(ALT)was also higher in the I/R group than in the nitrite group(34±6μkat vs 14±1.5μkat,P=0.0045).The NOx in MD was significantly higher in the nitrite group than in the I/R group(10.1±2.9μmol/L vs 3.2±0.9μmol/L,P=0.031)after the administration of nitrite.During ischemia,the levels decreased in both groups and then increased again during reperfusion.At the end of reperfusion,there was a tendency towards a higher NOx in the I/R group than in the nitrite group(11.6±0.7μmol/L vs 9.2±1.1μmol/L,P=0.067).Lactate in MD was significantly higher in the IR group than in the nitrite group(3.37±0.18 mmol/L vs 2.8±0.12 mmol/L,P=0.01)during ischemia and the first 30 min of reperfusion.During the same period,glycerol was also higher in the IRI group than in the nitrite group(464±38μmol/L vs 367±31μmol/L,P=0.049).With respect to histology,there were more signs of tissue damage in the I/R group than in the nitrite group,and29%of the animals in the I/R group exhibited necrosis compared with none in the nitrite group.Inducible nitric oxide synthase transcription increased between early ischemia(t=15)and the end of reperfusion in both groups.CONCLUSION:Nitrite administered before liver ischemia in the rat liver reduces anaerobic metabolism and cell necrosis,which could be important in the clinical setting.

Neutrophil-mediated liver injury during hepatic ischemia-reperfusion in rats

BACKGROUND: Neutrophil plays an important role in hepatic ischemia-reperfusion injury. We investigated neutrophil infiltration in liver tissue, Kupffer cells' role in neutrophil accumulation, and apoptosis and regeneration of hepatocytes in liver ischemia-reperfusion injury. METHODS: Vascular microclamps were placed across the pedicles of the median and left lateral lobes for 90 minutes after 30% hepatectomy with the resection of caudate, right lateral and quadrate lobes and papillary process. Gadolinium chloride (GdCl3) was used to destroy Kupffer cells. Neutrophil activity was inhibited with Urge-8, a monoclonal antibody against neutrophil produced in our laboratory. GdCl3 (10 mg/kg) and Urge-8 (50 mg/kg) were given intravenously in respective groups. Ischemia control, GdCl3 and Urge-8 groups were compared. RESULTS: Following hepatic reperfusion, serum interleukin-8 (IL-8) levels and hepatic neutrophil counts peaked at 3 hours, and peak concentrations of alanine aminotransferase (ALT) occurred at 6 hours. Animals of the control group showed increases in neutrophil infiltration in liver tissue, liver enzyme levels, and apoptosis index of hepatocytes and decreases in overall survival rate and proliferating cell nuclear antigen (PCNA) expression of hepatocytes. The survival rates and PCNA proportion of hepatocytes were higher and the levels of hepatic neutrophil infiltration, liver enzymes, and hepatocyte apoptosis after reperfusion were lower in the GdCl3 and Urge-8 groups than those in the ischemia control group. CONCLUSIONS: Blockades of Kupffer cells' activity and neutrophil infiltration by GdCl3 and Urge-8 eliminate neutrophil-mediated hepatic injury and enhance subsequent hepatic regeneration during liver ischemiareperfusion.

Heat shock protein 72 normothermic ischemia,and the impact of congested portal blood reperfusion on rat liver

INTRODUCTIONFrom the technical aspect of liver surgery ,control of bleeding during hepatic parenchymal resection is one of the most important procedures in hepatectomy .Pringle,s maneuver ,a temporary cross-clamping of the hepatoduodnal ligament ,has often been used for this purpose[1],This is the simplest and userul technique to reduce intraoperative blood loss .