Splenic artery ligation: A protection against hepatic ischemia/reperfusion injury in partially hepatectomized rats.

AIM: In liver resection, the temporary occlusion of the hepatoduodenal ligament (Pringle maneuver) is often used. However, the maneuver causes ischemia/reperfusion (I/R) injury in the remnant liver. Heme oxygenase (HO)-1 has a cytoprotective role against this injury. Our aim is to investigate whether splenic artery ligation induces HO-1 expression in the liver and ameliorates the hepatic I/R injury in partially hepatectomized rats. METHODS: Rats underwent splenic artery ligation by occluding the main splenic artery. Two days later, the total hepatic ischemia (Pringle maneuver) was conducted, and then a two-thirds partial hepatectomy (PH) was performed just before the start of reperfusion. HO inhibitor was twice injected s.c. at 3 and 16 h before the Pringle maneuver. HO-1 levels were determined by western blotting. Liver injury was biochemically assessed. RESULTS: In normal rats, HO-1 was highly expressed in the spleen, but not in the liver. Splenic artery ligation induced HO-1 in the livers. When rats underwent 20 and 30 min of Pringle maneuver/PH, survival rates were 28% and 8%, respectively. Splenic artery ligation significantly improved both the survival rates: 73% and 56%, respectively. Under these conditions, administration of HO-1 inhibitor at least partly negated the efficacy of splenic artery ligation. Splenic artery ligation also increased the recovery rate of the remnant liver mass and platelet counts in Pringle maneuver/PH-treated rats. CONCLUSION: Splenic artery ligation was significantly effective on the hepatic I/R injury in partially hepatectomized rats. Induction of HO-1 may be at least partly involved in the improvement of this injury.

Effect of non-essential amino acid glycine administration on the liver regeneration of partially hepatectomized rats with hepatic ischemia/reperfusion injury.

BACKGROUND & AIMS: Liver regeneration after partial hepatectomy or transplantation is a critical problem to affect prognosis. Ischemia/reperfusion (I/R) is an unavoidable process during liver resection or transplantation. The aim of this study was to investigate the effect of glycine on the regeneration of the remnant liver with I/R injury after partial hepatectomy. METHODS: Partially hepatectomized rat with liver I/R injury was prepared by a two-thirds partial hepatectomy following 30 min of total hepatic ischemia. Glycine (5% in water) was orally administered to rats for 3 days as drinking water before the surgery. RESULTS: Mortality rate in partially hepatectomized rats with severe hepatic I/R injury was so high compared to that in the rats with partial hepatectomy alone. However, when glycine was given to the partially hepatectomized rats with hepatic I/R injury, the survival rate, the recovery rate of the remnant liver weight, and the liver injury were obviously improved. On the other hand, when glycine-treated rats underwent partial hepatectomy without hepatic I/R, the recovery rate of the remnant liver weight was decreased as compared with that of the rats with partial hepatectomy alone. In these settings, glycine administration prevented the elevation of serum TNF-alpha levels and liver TNF-alpha mRNA expression. CONCLUSIONS: Glycine improved the regeneration of the remnant liver with severe I/R injury after partial hepatectomy. This improvement may be at least partly due to the amelioration of the hepatic I/R injury by glycine. Glycine seems to be clinically beneficial to the prognosis of patients with liver resection.

Effects of free radical scavenger on acute liver injury induced by d-galactosamine and lipopolysaccharide in rats.

AIM: Acute severe liver injury still has a high mortality rate. Acute liver injury induced by a coadministration of d-galactosamine (GalN) and lipopolysaccharide (LPS) is an experimental model of fulminant hepatitis in rats. Our aim is to investigate the effects of free radical scavenger on the injury induced by GalN/LPS in rats. METHODS: Free radical scavenger edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one) was twice injected into rats 5 min before and 60 min after the GalN/LPS injection. Liver injury was biochemically and histologically assessed. The survival rate was examined 72 h after the intoxication. RESULTS: In the GalN/LPS-treated rats, a marked elevation in serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels was observed. On the other hand, edaravone significantly inhibited the elevation in serum AST and ALT levels. The efficacy of edaravone was also confirmedby histological analysis. Edaravone lowered the levels of proinflammatory cytokines TNF-alpha mRNA and interleukin-6 mRNA expression, antioxidative enzyme heme oxygenase-1 protein and myeloperoxidase activity, a marker of neutrophil infiltration, in rat livers. In addition, edaravone reduced the mortality rate in GalN/LPS-treated rats as compared to the rats without edaravone treatment. CONCLUSIONS: Free radical scavenger edaravone effectively ameliorated the liver injury induced by the GalN/LPS administration in rats, not only by attenuating oxidative stress, but also by reducing the expression of proinflammatory cytokines.

Amelioration of hepatic ischemia/reperfusion injury in the remnant liver after partial hepatectomy in rats.

BACKGROUND AND AIMS: Reactive oxygen species have been implicated in the development of hepatic ischemia/reperfusion (I/R) injury. I/R injury remains an important problem in massive hepatectomy and organ transplantation. The aim of this study was to examine the effect of edaravone, a newly synthesized free radical scavenger, on I/R injury in the remnant liver after partial hepatectomy in rats. METHODS: Partial (70%) hepatic ischemia was induced in rats by occluding the hepatic artery, portal vein, and bile duct to left and median lobes of liver. Total hepatic ischemia (Pringle maneuver) was induced by occluding the hepatoduodenal ligament. Edaravone was intravenously administered to rats just before reperfusion and partial (70%) hepatectomy was performed just after reperfusion. RESULTS: Edaravone significantly reduced the increases in the levels of serum alanine aminotransferase and aspartate aminotransferase in rats with liver injury induced by 90-min of partial ischemia followed by 120-min of reperfusion. Histopathological analysis showed that edaravone prevented inflammatory changes in the livers with I/R injury. Edaravone also decreased the levels of myeloperoxidase activity, which is an index of neutrophil infiltration, and interleukin-6 mRNA, which is a proinflammatory cytokine. Additionally, edaravone improved the survival rate in partial hepatectomy rats with I/R injury induced by the Pringle maneuver. CONCLUSIONS: Edaravone administration prior to reperfusion protected the liver against I/R injury. Edaravone also improved the function of the remnant liver with I/R injury after partial hepatectomy. Therefore, edaravone may have applicability for major hepatectomy and liver transplantation in the clinical setting.

Splenic artery ligation improves remnant liver function in partially hepatectomized rats with ischemia/reperfusion injury.

BACKGROUND: In liver resection, the temporary occlusion of the hepatoduodenal ligament (Pringle maneuver) is often used. However, the maneuver causes severe ischemia/reperfusion injury in the remnant liver. Our aim was to investigate the effects of splenic artery ligation on the liver function in partially hepatectomized rat with the Pringle maneuver. METHODS: The Pringle maneuver was conducted for 30 min just before a two-thirds partial hepatectomy. Splenic artery ligation was performed before the Pringle maneuver. The efficacy of splenic artery ligation was assessed by survival, serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), recovery of remnant liver weight, and portal pressure. RESULTS: On day 3, animal survival was four rats of 12 in partially hepatectomized rats with the Pringle maneuver and 10 rats of 12 in the splenic artery ligation-treated partially hepatectomized rats with the Pringle maneuver. A two-thirds partial hepatectomy alone or splenic artery ligation itself did not show any effects on the survival. Compared with partially hepatectomized rats with the Pringle maneuver, splenic artery-ligated animals had lower serum AST and ALT levels, and higher recovery of remnant liver weight. Splenic artery ligation significantly reduced the portal pressure and also decreased the fatality in excessively hepatectomized rats. CONCLUSIONS: Splenic artery ligation ameliorated the remnant liver function in partially hepatectomized rats with the Pringle maneuver and excessively hepatectomized rats. The amelioration may be mediated at least by decreasing portal pressure.

Splenic artery ligation ameliorates hepatic ischemia and reperfusion injury in rats.

BACKGROUND/AIMS: Hepatic injury caused by ischemia/reperfusion (I/R) is a key clinical problem associated with liver transplantation and liver surgery. The spleen is involved in hepatic I/R injury. In this study, we examined the effects of splenic artery ligation on hepatic I/R injury. METHODS: Splenic artery ligation was performed 7 days, 3 days, or just before the hepatic ischemia. Hepatic ischemia was conducted by occluding the blood vessels to the median and left lateral lobes with an atraumatic vascular clamp. Hepatic I/R injury was induced by 45 min of ischemia followed by 120 min of reperfusion. RESULTS: When splenic artery ligation was performed at 3 days or just before the ischemia, serum aspartate transaminase and alanine transaminase activities, as markers for hepatic injury, decreased as compared with the rats with I/R alone. Splenic artery ligation also reduced the myeloperoxidase activity, an enzyme present in neutrophils, and the expression of interleukin-6 mRNA, a proinflammatory cytokine, in rat livers with I/R. Efficacy of splenic artery ligation on hepatic I/R injury was also confirmed by histology. On the other hand, when splenic artery ligation was conducted 7 days before the ischemia, efficacy of splenic artery ligation was disappeared. CONCLUSIONS: Splenic artery ligation ameliorates hepatic I/R injury in rats. These results strongly suggest the clinical usefulness of this surgical procedure to protect the liver against I/R injury.

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

BACKGROUND/AIMS: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Edaravone protects against lung injury induced by intestinal ischemia/reperfusion in rat.

Intestinal ischemia/reperfusion (I/R) is a critical and triggering event in the development of distal organ dysfunction, frequently involving the lungs. Respiratory failure is a common cause of death and complications after intestinal I/R. In this study we investigated the effects of edaravone (3-methyl-1-phenyl-2-pyrazoline-5-one) on the prevention of lung injury induced by intestinal I/R in rats. Edaravone has been used for protection against I/R injury in patients with cerebral infarction. When rats were subjected to 180 min of intestinal ischemia, a high incidence of mortality was observed within 24 h. In this situation, intravenous administration of edaravone just before the start of reperfusion reduced the mortality in a dose-dependent manner. To examine the efficacy of edaravone on the lung injury induced by intestinal I/R in more detail, we performed 120 min of intestinal ischemia followed by 120 min of reperfusion. Edaravone treatment decreased the neutrophil infiltration, the lipid membrane peroxidation, and the expression of proinflammatory cytokine interleukin-6 mRNA in the lungs after intestinal I/R compared to the I/R-treated rat lungs without edaravone treatment. Histopathological analysis also indicated the effectiveness of edaravone. In conclusion, edaravone ameliorated the lung injury induced by intestinal I/R, resulting in a reduction in mortality.

Pharmacological preconditioning protects lung injury induced by intestinal ischemia/reperfusion in rat.

Intestinal ischemia/reperfusion (IIR) is a critical and triggering event in the development of distal organ dysfunction, frequently involving the lungs. Respiratory failure is a common cause of death and complications after intestinal I/R. Stress protein heme oxygenase-1 (HO-1) confers the protection against a variety of oxidant-induced cell and tissue injuries. The aim of this study was to investigate the hypothesis that the induced HO-1 expression by pharmacological preconditioning with anticancer drug doxorubicin (Dox) could protect the lung injury induced by intestinal I/R. Intravenous administration of Dox induced HO-1 expression in the lungs and high levels of the expression were sustained at least to 48 h after the injection. Therefore, as pharmacological preconditioning, a low dose of Dox was injected intravenously into rats at 48 h before the start of intestinal ischemia. Rats underwent intestinal I/R by superior mesenteric artery occlusion for 120 min followed by 120 min of reperfusion. Preconditioning with Dox significantly ameliorated the lung injury induced by the intestinal I/R. Administration of a specific inhibitor of HO activity reduced the efficacy of the preconditioning. Our results suggest that this improvement may be mediated at least in part by the HO-1 induction. These findings may offer interesting perspectives for patient management In Intestinal surgical operation and intestine transplantation.

Splenectomy ameliorates hepatic ischemia and reperfusion injury mediated by heme oxygenase-1 induction in the rat.

BACKGROUND/AIMS: Ischemia/reperfusion (I/R) induces severe organic injury. I/R injury seems to be mainly caused by oxidative stress. The aim of this study was to determine the role of the spleen in experimental hepatic I/R injury in the rat. Stress protein heme oxygenase (HO)-1 plays a protective role against the oxidative injury. In normal state, HO-1 is highly expressed in the spleen. METHODS: Liver HO-1 expression was assessed by Western blot before and after splenects. Liver injury was assessed by measurement of ALT and AST and by histopathology. RESULTS: Although HO-1 was not detected in normal liver, levels of HO-1 protein gradually increased and peaked on 3 days after splenectomy. When splenectomy was performed 3 days prior to the hepatic (45-min) ischemia followed by (2-h) reperfusion, the levels of serum aspartate transaminase (AST) and alanine transaminase (ALT), as markers for hepatic injury, were improved compared to the rats with I/R alone. In addition, prior administration of zinc-protoporphyrin IX, a specific inhibitor of HO, suppressed the protective effect of the splenectomy on the subsequent hepatic I/R injury. Histopathological examination also confirmed these results. CONCLUSIONS: Our findings suggest that the elevated HO-1 levels by splenectomy play a protective role against hepatic I/R injury.

Hemolysate pretreatment ameliorates ischemic acute renal injury in rats.

Heme oxygenase-1 (HO-1) is an antioxidant enzyme and is believed to protect against oxidative stress-induced tissue injury. Renal ischemia-reperfusion (IR) injury seems at least in part to be caused by the oxidative stress. The aim of this study was to improve the renal IR injury by clinically available means. When littermate hemolysate was intravenously administered into rats, HO-1 was markedly induced in the kidneys. To investigate whether prior induction of HO-1 by the hemolysate injection ameliorates the subsequent renal IR injury, we assessed the levels of blood urea nitrogen (BUN) and serum creatinine (SCr), markers for renal injury, in rats with 45 min of ischemia followed by 18 h of reperfusion. To avoid the nephrotoxicity induced by hemolysate, small but effective amounts of hemolysate was injected into rats at 48 h prior to the ischemia. The levels of BUN and SCr values were significantly improved as compared to the rats with renal IR injury alone. Administration of HO inhibitor abolished the efficacy of hemolysate pretreatment. Our findings indicated that the prior induction of HO-1 by treatment of littermate hemolysate ameliorated the subsequent renal IR injury. Prior injection of self-hemolysate would be clinically useful for the protection against the renal IR injury induced by kidney transplantation and kidney surgery without immunological and infectious problems.

Prior induction of heme oxygenase-1 with glutathione depletor ameliorates the renal ischemia and reperfusion injury in the rat.

Heme oxygenase (HO)-1 catalyzes the rate-limiting step in heme degradation releasing iron, carbon monoxide, and biliverdin. Induction of HO-1 occurs as an adaptive and protective response to oxidative stress. Ischemia and reperfusion (IR) injury seems to be mainly caused by the oxidative stress. In this study, we have examined whether prior induction of HO-1 with buthionine sulfoximine (BSO), a glutathione (GSH) depletor, affects the subsequent renal IR injury. BSO (2 mmol/kg body weight) was administered intraperitoneally into rats, the levels of HO-1 protein increased within 4 h after the injection. When BSO was administered into rats at 5 h prior to the renal 45 min of ischemia, the renal IR injury was assessed by determining the levels of blood urea nitrogen and serum creatinine, markers for renal injury, after 24 h of reperfusion. The renal injury was significantly improved as compared to the rats treated with IR alone. Administration of zinc-protoporphyrin IX, an inhibitor of HO activity, reduced the efficacy of BSO pretreatment on the renal IR injury. Our findings suggest that the prior induction of HO-1 ameliorates the subsequent renal IR injury.