Total Hepatic Ischemia Research Articles

Interleukin-6 and STAT3 protect the liver from hepatic ischemia and reperfusion injury during ischemic preconditioning

Ischemic preconditioning has been shown to protect the liver from ischemia/reperfusion injury. We hypothesized that IL-6 directly modulates the protective effects of ischemic preconditioning. Three weeks after undergoing splenic transposition, wild-type C57BL/6 and IL-6 null mice underwent 75 minutes of total hepatic ischemia with or without prior ischemic preconditioning (10 minutes of ischemia followed by 15 minutes of reperfusion). After reperfusion, serum ALT, serum IL-6, hepatic IL-6 mRNA, hepatic pSTAT3, and liver histology were evaluated. In wild-type mice, survival at 24 hours was greater in the preconditioned group compared with the non-preconditioned group (75% vs 40%, P<.05). In IL-6 null mice, however, ischemic preconditioning did not improve survival when compared with the non-preconditioned group. Preconditioning significantly reduced hepatocellular injury in wild-type mice (P<.05) when compared with IL-6 null animals. This protection was associated with significant increases in serum IL-6, hepatic IL-6 mRNA, and hepatic pSTAT3 levels (P<.05). The protective effects of ischemic preconditioning that correlated with significant increases in systemic IL-6, hepatic IL-6 mRNA abundance, and pSTAT3 levels, were not observed in IL-6 null mice. The protective effects of ischemic preconditioning during total hepatic ischemia/reperfusion injury are dependent on IL-6 signaling and are associated with increased phosphorylation of hepatic STAT3.

Expression of toll-like receptor 2/4 on alveolar macrophage in the model of total hepatic ischemia/reperfusion injury in mice

Objective: To explore the expression and meaning of Toll-like receptor 2/4 in alveolar macrophage during the process of total hepatic ischemia in mice. Methods: BALB/c mice were used in a model of total hepatic ischemia/reperfusion. Alveolar Macrophage were collected at the time point of 1h, 6h and 12h by the means of bronchoalveolar lavage (BAL), and its TLR2/4 mRNA and protein were detected with Flow Cytometry and Real-time PCR. The level of TNF in BAL fluid were measured. The concentration of MPO, the ratio of wet/dry and lung histological scores were used to assess the degrees of lung injuries. Results: At the three time points of hepatic ischemia reperfusion, the expression of TLR2/4 protein of and mRNA were up-regulated and the level of TLR2 was on the rise continually. TLR4 at the time of 6 h reached the peak value (P<0.01). The level of TNF-2 in BAL fluid reached the highest point at the time of 6 h (P<0.01). The ratio of wet/dry rose continually during hepatic ischemia reperfusion. After 1 h, the level of MPO increased rapidly. Then it reached the peak value during the period of 6 h to 12 h. Conclusion: TLR2/4 on the mice of alveolar macrophage were activated in the process of hepatic ischemia/reperfusion and involved in the injury of lung.

The effects of desferrioxamine and quercetin on hepatic ischemia–reperfusion induced renal disturbance

Background The aim of this study was to analyze the effects of 45 min of hepatic ischemia and 1 h of reperfusion on renal oxidative stress parameters, on renal tissue damage, and the role of Desferrioxamin (Dfx) and Q on these parameters. Methods Thirty Wistar albino rats were randomized to five groups. Group I was the control group. Group II received no treatment. Groups III and IV received intramuscular injections of desferrioxamine (100 mg/kg) and quercetin (50 mg/kg), respectively. Group V was administered Dfx and quercetin in combination. After treatment for 3 days, groups II, III, IV, and V were exposed to total hepatic ischemia for 45 min. Plasma alanine aminotransferase levels, renal malondialdehyde and reduced glutathione (GSH) activities were measured after reperfusion for 1 h. Histopathological and ultrastructural analysis of renal tissues was carried out. Results Plasma creatinine and BUN levels were markedly increased in the IR group and pretreated groups. Kidney MDA increased in the IR group, Q and Dfx+Q significantly decreased kidney MDA Kidney GSH levels markedly decreased in the IR group, Dfx significantly increased kidney GSH. No evidence of overt injury was observed in any renal tissue under light and electron microscopy. Conclusions Our data demonstrated that 45 min of hepatic ischemia and 1 h of reperfusion may alter renal functions and may cause oxidative stress on renal tissue. Q and Dfx seem to have a beneficial effect via the GSH system and modulation of MDA levels.

The Protective Effect of α-Tocopherol and GdCl3 Against Hepatic Ischemia/Reperfusion Injury

To evaluate the combined effect of alpha-tocopherol and gadolinium chloride (GdCl3) in reducing lipid peroxidation after severe hepatic ischemia/reperfusion (IR) injury. Sixty male Wistar rats, 200-250 g, were randomly divided into six equal groups. There were two sham operation (SHAM) groups, two untreated IR groups, and two IR groups treated with GdCl3 and alpha-tocopherol (IRGT). After 60 min of total hepatic ischemia and 120 min reperfusion, one of each group was killed, liver samples were taken for malondialdehyde (MDA) and myeloperoxidase (MPO) analysis and light microscopy examination, and blood samples were analyzed for aspartate (AST) and alanine (ALT) transaminase, lactate dehydrogenase (LDH), and alpha-tocopherol content. The remaining groups were monitored for survival rate determination. The mean MDA and MPO values in the SHAM, IR, and IRGT groups, respectively, were 1.117, 1.476, and 0.978 nmol/g wet tissue and 1.49, 6.26, and 1.78 (U/g). The mean alpha-tocopherol values in the SHAM, IR, and IRGT groups, respectively, were 10.4, 1.9, and 12 micromol/l. The mean serum AST, ALT, and LDH values were significantly higher in the IR group than in the SHAM group (P < 0.001), and significantly lower in the IRGT group than in the IR group (P < 0.001). Light microscopy examination revealed more severe congestion and vacuolization in the IR group than in the SHAM group, and minimal congestion and vacuolization in the IRGT group. Survival was significantly higher in the IRGT group than in the IR group. The administration of GdCl3 and alpha-tocopherol is likely to protect the liver against lipid peroxidation by suppressing Kupffer cell and polymorphonuclear leukocyte activation and enhancing endogenous antioxidant activity.

Total hepatic ischemia and reperfusion after state controlled hemorrhagic shock, with used of different solutions: effects of neutrophils sequestration in kidney of rats

PURPOSE: To evaluate and compare neutrophils sequestration in the renal cortex of rats, result of total hepatic ischemia and reperfusion after controlled hemorrhagic shock, with use of different electrolytic solutions. METHODS: Used 18 rats Wistar, males, adult, divided into three groups as the solution used to reanimation: Group PSS: physiologic saline solution; Group HSS: hypertonic saline hypertonic (7,5%) followed by lactated ringer's solution; Group LRS: lactated ringer's solution. All the animals were submitted to the bleeding controlled until mean arterial pressure (MAP) 40 mmHg, for 20 minutes. Performed volemic replacement until PAM=80 mmHg with the solution according the studied group, followed by laparotomy and Pringle's Maneuver for 15 minutes. The animals were accompanied until for two hours. To statistical comparisons between mean of neutrophils sequestration, in interstitium of the renal cortex, were made the tests One-way ANOVA and covariance analysis, adjusting itself for time of supervened. The hemodynamic parameters evaluated were: MAP, heat rate, cardiac index, vascular resistance system index. The analyzed metabolic variables were: pH, bicarbonate, base deficit and lactato, besides electrolytes. RESULTS: The mean values of supervened, in minutes, for group were: Group PSS 79,0±12,0; Group LRS 97,0±11,0; Group HSS 67,0±10. The mean values of neutrophils/field in the renal cortex were: Group PSS 0,55±0,68; Group LRS 1,68±0,53; Group HSS 1,33±0,43. When adjusted for time of supervened: Group PSS 0,55; Group LRS 1,62; Group HSS 1,39. There was statistically significant difference in neutrophils sequestration, between Group PSS regarding the others groups, using itself or not the adjustment by time of supervened (p=0,016 and p=0,0128). CONCLUSION: Both critical situations in this model, controlled hemorrhagic shock followed by Pringle's maneuver, promoted neutrophils sequestration in the interstitium renal of rat, and the physiologic saline solution demonstrated minor mean, differentiating statistically of the others solutions.

The Effects of Desferrioxamine and Quercetin on Liver Injury Induced by Hepatic Ischaemia-Reperfusion in Rats

Background: This study was designed to examine the effects of desferrioxamine and quercetin on hepatic ischaemia-reperfusion injury in rat.Methodology: Thirty Wistar albino rats were randomized into five groups. Group I was the control group. Group II received no treatment. Group III and group IV received intramuscular injections of desferrioxamine (100 mg/kg per day) and quercetin (50 mg/kg per day) respectively. Group V was administered desferrioxamine and quercetin in combination. After treatment for 3 days, groups II, III, IV, and V were exposed to total hepatic ischaemia for 45 minutes. Plasma alanine aminotransferase levels, malondialdehyde and reduced glutathione activities were measured after reperfusion for 1 hour. Histopathological analysis of liver tissues was carried out.Results: Our results indicated that tissue malondialdehyde levels and histopathological liver damage scores were significantly higher in the ischaemia-reperfusion group than in the control group. Administration of desferrioxamine, quercetin, and desferrioxamine+quercetin significantly decreased these parameters. Plasma alanine aminotransferase levels were also increased after ischaemia-reperfusion. Quercetin and desferrioxamine + quercetin significantly decreased the activity of this enzyme when compared to ischaemia-reperfusion group.Conclusions: The present data suggest that both desferrioxamine and quercetin may be useful to protect against ischaemia-reperfusion induced liver damage.

Identification and preliminary validation of novel biomarkers of acute hepatic ischaemia/reperfusion injury using dual-platform proteomic/degradomic approaches

Hepatic ischaemia/reperfusion (I/R), a major cause of liver damage associated with multiple trauma, haemorrhagic and septic shock, and liver transplantation, contributes significantly to multiple organ failure. Development of novel sensitive biomarkers that detect early stages of liver damage is vital for effective management and treatment of ischaemic liver injury. By using high-throughput immunoblotting and cation–anion exchange chromatography/reversed-phase liquid chromatography-tandem mass-spectrometry, we identified several hepatic proteins, including argininosuccinate synthase (ASS) and estrogen sulfotransferase (EST-1), which were degraded in the liver and rapidly released into circulation during I/R injury. ASS accumulated in serum within 10 min, reached a steady state at 30 min, and persisted up until 3 h after reperfusion following 30 min of total hepatic ischaemia. EST-1 appeared rapidly in blood and attained maximum within 1 hour followed by a decline at 3 h of reperfusion. No ASS or EST-1 protein was detected in serum of control or sham operated rats. ASS and EST-1 exhibited greater sensitivity and specificity toward I/R liver injury as compared with alanine aminotransferase (ALT), an established marker of hepatocellular necrosis. In contrast, serum ASS and EST-1 were undetectable in rats with chronic alcoholic liver disease, while the levels of ALT protein were significantly increased. In addition, ASS, but not EST-1 or ALT accumulated in blood only 6 h after treatment with hepatotoxic combination of lipopolysaccharide and D-galactosamine. These data demonstrate the utility of ASS and EST-1 as novel sensitive and specific biomarkers of acute liver ischaemic injury for prospective clinical studies.

Total hepatic ischaemia in the Rhesus monkey

During operations for major hepatic trauma it may be necessary temporarily to deprive the liver of its blood supply by occlusion of the hepatic artery and portal vein. The maximum 'safe period' of total hepatic ischaemia in man is unknown. In the monkey the ischaemic liver 'leaks' potassium, and levels of this element in the hepatic veins rise during ischaemia reaching a peak immediately after blood supply to the liver is restored. However, critical systemic levels of potassium are never reached and severe biochemical disturbance does not occur until 2 h following revascularization in animals having experienced ischaemic periods of longer than 20 min.

Isquemia e reperfusão hepática total em condições de normalidade e sob estado de choque hemorrágico controlado: efeitos no sequestro de neutrófilos no rim do rato

The evaluate the effects of total hepatic ischemia and reperfusion under normal conditions and submitted to controlled hemorrhagic shock state on the accumulation of neutrophils in the cortex renal of rats. In this experiment 32 male adult Wistar mice, were divided into four groups: Control Group (CG), submitted to the catheterizations and laparotomy, followed by a period 60 minutes of observation; Shock Group (SG): controlled of hemorrhagic shock (CHS) for 20 minutes (20'), mean arterial pressure (MAP) 40 mmHg, followed by reanimation and reperfusion for 60 minutes (RP60); Pringle Group (PG): Pringle's Maneuver (PM) for 15 minutes (15'), followed for RP60'; Shock-Pringle Group (SPG): CHS (MAP = 40 mmHg) for 20' followed by laparotomy and PM for 15', followed for RP60'. To characterize the poor tissular perfusion blood lactate and the base reserve were measured. The means values neutrophils were: CG = 0.24 (+/-0.28); SG = 1.06 (+/-0.61); PG = 0.18 (+/-0.16); SPG = 0.24 (+/-0.19). The CG demonstrated significant neutrophils accumulation in the renal córtex, when compared between others groups. In this experimental study showed that CHS for 20' followed for RP60 was principal factor by major sequestration of neutrophils in the renal cortex of rats.

Effects of prior splenectomy on remnant liver after partial hepatectomy with Pringle maneuver in rats

In the case of the liver resection, the temporary occlusion of the hepatoduodenal ligament (Pringle maneuver) is often used. However, the maneuver causes hepatic ischemia/reperfusion (I/R) injury that strongly affects the recovery of patients. The present study investigated the effects of prior splenectomy on the remnant liver in partial hepatectomized rat with Pringle maneuver. Pringle maneuver was conducted just before a two-thirds partial hepatectomy. Efficacy of splenectomy was assessed by survival rate, serum alanine aminotransferase (ALT), neutrophil infiltration into liver, recovery of remnant liver weight, and liver proliferating cell nuclear antigen (PCNA) levels. Ischemic preconditioning was performed as follows; 10 min of total hepatic ischemia followed by 10 min of reperfusion. In partial hepatectomized rats with 30 min of Pringle maneuver, seven out of 12 rats died within 3 days. On the other hand, when splenectomy was performed on 3 days before the maneuver, only one out of 12 rats died. When prior splenectomy was performed on eight and 18 days before the Pringle maneuver, respectively, similar efficacy was observed. In addition, prior splenectomy on 3 days before the maneuver showed that serum ALT activity, neutrophil infiltration, recovery of remnant liver weight, and PCNA levels in partial hepatectomized rats with Pringle maneuver were also ameliorated as compared with those of control rats without splenectomy. When effects of prior splenectomy were compared with those of ischemic preconditioning in these situations, efficacy of prior splenectomy was comparable with that of the ischemic preconditioning. Prior splenectomy ameliorated the I/R injury in the remnant liver after partial hepatectomy with Pringle maneuver. Effects of prior splenectomy may influence the liver for long duration, because splenectomy on 18 days before the maneuver still exerts effective action.

Effects of Ischemic Preconditioning on Regenerative Capacity of Hepatocyte in the Ischemically Damaged Rat Livers

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. 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). 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. 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.

Splenic transposition is superior to caudal shunt as a model of murine total hepatic ischemia

Murine total hepatic ischemia (THI) followed by reperfusion without shunting of the portal vein induces significant lethality in rodents due to intestinal congestion. Two methods have been promulgated to study THI and reperfusion in mice without intestinal congestion: subcutaneous splenic transposition which creates a portosystemic shunt via epigastric vessels, and a caudal shunt with 30% hepatectomy, which creates a portosystemic shunt via the small remnant of remaining caudal lobe. We compared outcome, inflammatory response and hepatic injury due to THI and reperfusion in these two models. Female C57BL/6 mice underwent ST, caudal shunt or no surgery prior to having 30 min of total hepatic ischemia followed by 60 min of reperfusion. Survival, surgical complications, serum AST/ALT and IL-6 were determined. Apoptotic and necrotic hepatocytes were identified by morphological criteria. Complication rates for the ST and caudal shunt procedures were 6.7 and 20%, respectively. Subsequent mortality rates following THI and 60 min reperfusion were 5.9 and 50% in mice with ST and caudal shunt, respectively. Both groups had elevated serum AST/ALT concentrations. However, in mice undergoing caudal shunt, AST/ALT levels were also significantly increased even without THI. The number of apoptotic hepatocytes after THI and reperfusion in mice following caudal shunt was significantly higher compared with those of ST (P<0.001). Both ST and caudal shunt can be used in models of THI and reperfusion to prevent significant lethality due to intestinal congestion. However, ST is a simple, safe and suitable model, whereas caudal shunt requires manipulation of the liver, and is associated with significant hepatic injury and morbidity.

A model to study total hepatic ischemia–reperfusion injury

Background Most experimental animal models for studying hepatic ischemia–reperfusion injury (IRI) involve partial or segmental ischemia of the liver or a portocaval shunt procedure to avoid mesenteric congestion. However, these do not reflect the global ischemia that occurs during liver transplantation. A rabbit model of total hepatic ischemia without a portocaval shunt is described. Methods Twenty male New Zealand white rabbits (3.5 ± 0.3 kg) were allocated to four groups: group 1 ( n = 5), sham-operated; group 2 ( n = 5), 20-minute total hepatic ischemia; group 3 ( n = 5), 25-minute total hepatic ischemia; and group 4 ( n = 5), 30-minute total hepatic ischemia. Total hepatic ischemia was induced by occluding the portal inflow vessels (portal vein and artery) with an atraumatic vascular loop and were measurements taken for 2 hours during reperfusion. Results A total hepatic ischemia of 30 minutes caused severe liver injury resulting in cardiac arrest at 2 hours of reperfusion in all five animals due to metabolic acidosis. Twenty minutes of total ischemia was tolerated and did not produce significant liver injury. Twenty-five minutes of total ischemia was tolerated but at 2 hours of reperfusion, resulted in significant liver injury (68 ± 41, 283.0 ± 20.5, and 835.2 ± 52.7 U/L) compared with the sham-operated group (serum ALT, 25.4 ± 2.7; serum AST, 47.4 ± 3.0; serum LDH, 307.6 ± 44.4 U/L; P < .003). Conclusions Rabbits can tolerate 25 minutes of total hepatic ischemia without a portosystemic shunt. This 25-minute ischemia model simulates operative conditions during liver transplantation and will be valuable in studies modulating IRI.

Portosystemic Shunt Prevents Apoptosis in Rat Intestinal Mucosa Caused by Total Hepatic Ischemia

Background: Prolonged splanchnic congestion due to total hepatic ischemia (THI) has been shown to induce damage to the intestinal mucosa. The present study was conducted to examine whether the protective effect of portosystemic shunt (PSS) can be seen on apoptosis of intestinal mucosa in a rat model of THI. Methods:Adult male Wistar rats were divided into the following 3 groups: control group; the THI group underwent THI for 30 min, and the PSS group was subjected to THI for 30 min with PSS. Rats were killed after 1, 2, and 6 h of reperfusion. For each time point, levels of serum liver enzymes, intestinal morphology, malondialdehyde (MDA) contents and DNA fragmentation in intestinal tissue were determined. In addition, the 7-day survival rate was measured. Results: The 7-day survival rate of THI group remained at 50%, whereas that of PSS group was significantly higher at 90% (p < 0.01). Serum AST and ALT levels of the THI and PSS groups rapidly increased after reperfusion, reaching peak values at 2 h. MDA levels after 1 and 2 h of reperfusion in the THI group were significantly increased as compared with the control group (p < 0.001). Increases in the percentage of fragmented DNA peaked 1 h after reperfusion in the THI group. PSS resulted in the reduction of DNA fragmentation and preserved the macroscopic and microscopic appearance of the intestinal mucosa. Conclusions: Splanchnic congestion due to portal occlusion increased apoptosis in the rat intestinal mucosa. PSS is very effective in counteracting the principal negative effects of total hepatic ischemia.

Caspase-8 and caspase-3 small interfering RNA decreases ischemia/reperfusion injury to the liver in mice

BackgroundIschemia/reperfusion injury (I/R injury) of the liver remains a significant problem during liver surgery and transplantation. I/R injury is associated with liver apoptosis, which is mediated by death receptors such as Fas and tumor necrosis factor alpha (TNF-α), and/or mitochondrial dysfunction induced by cellular stress. Caspase-8 is presumed to be the apex of the death-mediated apoptosis pathway, whereas caspase-3 belongs to the “effector” proteases in the apoptosis cascade. Synthetic small interfering RNAs (siRNAs) specifically suppress gene expression by RNA interference. Therefore, we evaluated the therapeutic efficacy of caspase-8 and caspase-3 siRNA in a murine model of liver I/R injury. MethodsIn C57BL/6 mice, 45% or 70% of the liver mass was clamped for 90 minutes. For survival analysis, total hepatic ischemia was induced for 45 minutes. In vivo delivery of siRNA was performed via the portal vein by high-volume injection (0.5 nmol of siRNA in 1 mL containing 10% lipiodol) 60 minutes before ischemia. As a control, animals received either vehicle or non-sense siRNA (siRNA-scrambled). ResultsLiver uptake of siRNA was analyzed in transgenic mice who express β-galactosidase (β-gal) (C57BL/6J-TgN(MTn-LacZ)204Bri) after administration of siRNA-LacZ. A 3- to 4-fold decrease in β-gal activity was accomplished at 0.5 nmol. No significant change in β-gal activity was demonstrated in mice receiving non-sense siRNA. Immunohistochemical studies found that 60% of the liver cells efficiently took up siRNA. Significant reduction in serum aspartate transaminase was found in animals treated with siRNA caspase-8 or caspase-3 compared with siRNA-scrambed or vehicle-treated controls. More than a 60% reduction in caspase-8 and caspase-3 gene expression and activities was accomplished after siRNA administration. Animals treated with siRNA presented lower infiltration of polymorphonuclear leukocytes and better preservation of the liver architecture compared with controls. All of the control mice subjected to total liver ischemia died within 5 days. In contrast, 30% of the animals given siRNA caspase-8 and 50% of those treated with siRNA caspase-3 survived indefinitely (>30 days). ConclusionsSmall interfering RNA targeted to caspase-8 and caspase-3 provided significant protection against I/R injury to the liver. This approach could be therapeutic in liver transplantation and other conditions associated with I/R injury to the liver.

Protective effect of a human C5a receptor antagonist against hepatic ischaemia-reperfusion injury in rats

<h2>Abstract</h2><h3>Background/Aims</h3> Complement activation is induced by ischaemia-reperfusion (I/R) and the complement factor C5a plays an important role in organ specific I/R injuries. This study investigated the efficacy of a small molecule C5a receptor (C5aR) antagonist against hepatic I/R injury. <h3>Methods</h3> Total hepatic ischaemia or partial hepatic ischaemia were induced in rats, followed by a period of reperfusion. The C5aR antagonist, AcF-[OPdChaWR], was administered at 1 mg/kg i.v. or 10 mg/kg p.o. or s.c. before induction of ischaemia. Total hepatic I/R-induced mortality was measured and partial hepatic ischaemia injury was assessed by measuring the serum levels of liver enzymes, tissue or serum TNFα, liver and lung myeloperoxidase activity, the number of infiltrating neutrophils, neutrophilia and liver histopathology. <h3>Results</h3> C5aR antagonist treatment reduced total hepatic I/R-induced mortality. In partial hepatic I/R rats, treatment with the C5aR antagonist significantly attenuated the increases in liver enzymes, serum and tissue TNFα, myeloperoxidase activity, infiltrating neutrophils, neutrophilia, and also reduced liver histopathology. <h3>Conclusions</h3> This study shows that an orally active, small molecule C5aR antagonist is effective in reducing the markers of tissue damage caused by I/R in the rat, suggesting an important role for C5a in I/R injuries in the liver.

Protective effect of a human C5a receptor antagonist against hepatic ischaemia-reperfusion injury in rats

Background/Aims Complement activation is induced by ischaemia-reperfusion (I/R) and the complement factor C5a plays an important role in organ specific I/R injuries. This study investigated the efficacy of a small molecule C5a receptor (C5aR) antagonist against hepatic I/R injury. Methods Total hepatic ischaemia or partial hepatic ischaemia were induced in rats, followed by a period of reperfusion. The C5aR antagonist, AcF-[OPdChaWR], was administered at 1 mg/kg i.v. or 10 mg/kg p.o. or s.c. before induction of ischaemia. Total hepatic I/R-induced mortality was measured and partial hepatic ischaemia injury was assessed by measuring the serum levels of liver enzymes, tissue or serum TNFα, liver and lung myeloperoxidase activity, the number of infiltrating neutrophils, neutrophilia and liver histopathology. Results C5aR antagonist treatment reduced total hepatic I/R-induced mortality. In partial hepatic I/R rats, treatment with the C5aR antagonist significantly attenuated the increases in liver enzymes, serum and tissue TNFα, myeloperoxidase activity, infiltrating neutrophils, neutrophilia, and also reduced liver histopathology. Conclusions This study shows that an orally active, small molecule C5aR antagonist is effective in reducing the markers of tissue damage caused by I/R in the rat, suggesting an important role for C5a in I/R injuries in the liver.

Blockade of receptor for advanced glycation end product (RAGE) attenuates ischemia and reperfusion injury to the liver in mice.

Hepatic ischemia/reperfusion (I/R) injury associated with liver transplantation and hepatic resection is characterized by hepatocellular damage and a deleterious inflammatory response. In this study, we examined whether receptor for advanced glycation end product (RAGE) activation is linked to mechanisms accentuating inflammation on I/R in a murine model of total hepatic ischemia. Animals treated with soluble RAGE (sRAGE), the extracellular ligand-binding domain of RAGE, displayed increased survival after total hepatic I/R compared with vehicle treatment. TUNEL assay and histologic analysis revealed that blockade of RAGE was highly protective against hepatocellular death and necrosis on I/R; in parallel, proliferating cell nuclear antigen was enhanced in livers of mice treated with sRAGE. Rapid activation of p38, p44/42, stress-activated protein kinase and c-Jun N-terminal kinase mitogen-activated protein kinases, signal transducer and activator of transcription-3, and nuclear translocation of activator protein-1 was evident at early times on I/R. In the remnants of sRAGE-treated livers, however, activation of each of these signaling and transcription factor pathways was strikingly decreased. sRAGE-treated remnants displayed enhanced activation of nuclear factor kappaB, in parallel with increased transcripts for the proregenerative cytokine, tumor necrosis factor-alpha. In conclusion, these data suggest that RAGE modulates hepatic I/R injury, at least in part by activation of key signaling pathways linked to proinflammatory and cell death-promoting responses. We propose that blockade of this pathway may represent a novel strategy to attenuate injury in hepatic I/R and to facilitate regeneration.

High dose intravenous immunoglobulin g pretreatment: effect on lipid peroxidation and reperfusion injury to the liver.

The aim of this study was to examine the effect of intravenous immunoglobulin G (IVIG) compared with that of gadolinium chloride (GdCl3) in the inhibition of Kupffer cell activation on lipid peroxidation after severe total hepatic ischemia/reperfusion (I/R). Male Wistar rats ( n = 40) were randomly divided into four equal groups: a sham-operation group, a control I/R group, and two I/R groups pretreated with either IVIG or GdCl3 intravenously. Following 60 minutes of total hepatic ischemia and 120 minutes of reperfusion, the rats were sacrificed and liver and blood samples collected. Additional animals ( n = 80) were followed up for survival rate determination. Results showed that I/R decreased the survival rate to 10%, increased the levels of aspartate (AST) and alanine (ALT) transaminase and lactate dehydrogenase (LDH) in serum to 2487, 2189, and 4236 IU/L, respectively, and increased malondialdehyde (MDA) levels in liver to 1.552 nmol/g compared with 1.114 nmol/g in the sham operation group. Pretreatment with GdCl3 increased the survival rate to 50% and decreased the levels of AST, ALT, and LDH in serum to 1496, 1298, and 3245 IU/l, respectively. Pretreatment with IVIG increased the survival rate to 60% and decreased the levels of AST, ALT, and LDH in serum to 449, 367, and 1456 IU/l, respectively, and the levels of MDA in liver to 1.153 and 1.148 nmol/g for GdCl3 and IVIG respectively. Histologic examination showed protection of liver parenchyma in the animals treated with GdCl3 or IVIG.

Recruitment of neutrophils across the blood-brain barrier: the role of posttraumatic hepatic ischemia

PURPOSE: To study the effects of total hepatic ischemia, and reperfusion on the accumulation of neutrophils in the brain of rats submitted to normovolemic conditions as well as to controlled hemorrhagic shock state. METHODS: Thirty two adult male Wistar rats, were divided into four groups: the Control group, was submitted to the standard procedures for a period of 60 min of observation; Shock group, was submitted to controlled hemorrhagic shock (mean arterial blood pressure=40mmHg, 20min) followed by volemic resuscitation (lactated Ringer's solution + blood, 3:1) and reperfusion for 60min; Pringle group, was submitted to total hepatic ischemia for 15min and reperfusion for 60min. The total group was submitted to controlled hemorrhagic shock for 20min followed by volemic resuscitation (lactated Ringer's solution + blood, 3:1), total hepatic ischemia for 15min and reperfusion for 60min. Measurements of serum lactate and base excess were used to characterize the hemorrhagic shock state with low tissue perfusion. The counting of neutrophils on the brain was performed after the euthanasia of animals. RESULTS: The values for the counting of neutrophils on the brain indicate that did not occur difference among studied groups (p=0.196) (Control 0.12± 0.11, Shock 0.12± 0.13, Pringle 0.02± 0.04, Total 0.14± 0.16). CONCLUSION: Hemorrhagic shock associated to total hepatic ischemia for 15 minutes, followed by 60 minutes of reperfusion, did not causes significant neutrophils accumulation in the brain of rats.