Induction of adhesion molecule expression in liver ischaemia-reperfusion injury is associated with impaired hepatic parenchymal microcirculation

The effect of octreotide on hepatic ischemia-reperfusion injury in a rabbit model

BACKGROUND

Hepatic ischemic-reperfusion injury (HIRI) is a major cause of morbidity and mortality following liver surgery. Octreotide (Oct) has been reported to improve hepatocellular energy metabolism in a rat HIRI model. This study was designed to evaluate whether Oct could protect the liver of rabbits against ischemic-reperfusion (I/R) injury.

METHODS

Twenty-four adult New Zealand rabbits were randomly divided into a sham operated group (Control), an ischemia/reperfusion group (I/R), and an ischemia/reperfusion + Oct pretreatment group (I/R + Oct). The hemodynamic (mean arterial pressure [MAP] and heart rate [HR]) changes, liver enzymes (alanine aminotransferase [ALT], aspartate aminotransferase [AST], and lactate dehydrogenase [LDH]) release, inflammatory cytokines (tumor necrosis factor [TNF]α and interleukin [IL]-1β) levels, and endotoxin (ETX) levels were measured during I/R.

RESULTS

Compared with the Control group, the MAP decreased and HR increased in I/R and I/R + Oct groups at ischemia 15 minutes (P < .05) but were less in the I/R + Oct group relative to the I/R group (P < .05). ALT, AST, LDH, IL-1β, and ETX levels were increased in the I/R and I/R + Oct groups at ischemia 30 minutes (P < .05), however, the increase was lower in the I/R + Oct group relative to the I/R group (P < .05). Bcl-2 expression in the I/R + Oct group was higher compared with other groups (P < .05) and Bax expression in the I/R group was reduced compared with other groups (P < .05). Hepatocellular damage in the I/R + Oct group appeared to be less than in the I/R group by microscopy.

CONCLUSIONS

Oct pretreatment attenuated hemodynamic changes and decreased liver enzyme changes induced by HIRI in a rabbit model. The protection mechanisms of Oct may be related to reduced ETX levels, down-regulation of the inflammatory cytokines TNFα and IL-1β, and inhibition of hepatocellular apoptosis, as well as the modulation of the mitochondrion-mediated Bcl-2/Bax apoptosis pathway. Based on our study it appears that Oct may be useful in decreasing liver injury after liver surgery and/or transplantation and may serve as a promising agent against HIRI.

Inhibition of inducible nitric oxide synthase worsens liver damage regardless of lipopolysaccharide treatment in small-for-size liver transplantation

OBJECTIVE

In small-for-size liver transplantation, portal hypertension aggravates endotoxin from the gut which accelerates the activation of inducible nitric oxide synthase (iNOS). However, there is little knowledge as to the effects of iNOS inhibitors on small-for-size graft damage. Our study was designed to investigate the role of an iNOS inhibitor both with and without lipopolysaccharide (LPS) treatment in ischemia-reperfusion injury of small-for-size liver transplantation.

METHODS

Subjecting Sprague-Dawley rats to small-for-size grafts liver transplantation, we investigated the time course of changes in hepatic expression of iNOS and endothelial nitric oxide synthase (eNOS). Meantime, we also investigated the effects of iNOS inhibitor, both with and without LPS treatment, at 6h after reperfusion.

RESULTS

While iNOS mRNA expression reached a peak at 3h, the highest protein level occurred at 6h after reperfusion. Aminoguanidine (AG) significantly inhibited mRNA and protein expressions of iNOS, but not that of eNOS. However, LPS accelerated activation of iNOS, but suppressed the expression of eNOS. Meanwhile, compared with the untreated group, those treated with AG or LPS experienced worsened liver function and tissue damage, promoting neutrophil infiltration in the liver tissue. The difference between the LPS group and the LPS+AG group was found to be significant. In addition, AG and LPS treatments up-regulated the protein expression of ICAM-1 and NF-kappaB p65.

CONCLUSION

In a small-for-size model of rat liver transplantation, regardless of LPS treatment, the inhibitor of iNOS, AG, attenuated iNOS expression, but worsened liver function and tissue damage. The subsequent increased neutrophil infiltration in liver tissue may be associated with up-regulation of ICAM-1 and NF-kappaB expressions.

Protective effect of streptokinase on rat liver ischemia reperfusion injury

AIM: To study the protective effect of strep-tokinase on rat liver ischemia reperfusion injury.

METHODS: Thirty-six Wistar rats were divided randomly into control group and 2 experiment groups (12 in each group). Livers from the control group were perfused with 10 mL Ringer's solution through the portal vein and stored at 4 ℃ for 24 h. Livers from the experiment group were perfused with Ringer's solution containing 7500 IU streptokinase with or without hypothermal oxygen stored at 4 ℃ for 24 h. All cold storage livers were followed by in vitro perfusion at 37 ℃ for 45 min, and stored at 4 ℃. Changes in ALT, GLDH, and activity of PNP, 5'nucleotidase and bile secretion were detected.

RESULTS: The activity of ALT, GLDH and PNP was significantly lower in the experiment groups than in the control group(P < 0.05). Bile secretion(3.7 ± 0.7 µL/g at 45 min, 9.1 ± 0.7 µL/g at 45 min vs 1.1 ± 0.9 µL/g at 45 min, P < 0.05) and 5'nucleotidase activity were significantly increased in the experiment groups compared with the control group.

CONCLUSION: Streptokinase can improve rat liver microcirculation and ischemia reperfusion injury.

Effects of Huoxue Huayu injection I pretreatment and ischemic preconditioning on liver ischemia and reperfusion injury in rats

AIM: To investigate the effects of Huoxue Huayu injection I (HHI-I) pretreatment and ischemic preconditioning (IP) on hepatic ischemia and reperfusion (I/R) injury in rats and compare their efficacity.

METHODS: Eighty healthy adult male Sprague-Dawley rats were randomly and averagely divided into 4 groups: sham operation (SO) group, I/R group, ischemia preconditioning (IP) group, and HHI-I pretreatment group. After partial hepatic I/R model was made, the rats of each group were sacrificed to determine serum alanine aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), tissue malondialdehyde (MDA) and superoxide dismutase (SOD) level 1、3、6、24 h after reperfusion, respectively. Tissue tumor necrosis factor alpha (TNF-α) and intercellular adhesion molecule-1 (ICAM-1) mRNA levels were determined by reverse transcription-polymerase chain reaction after 1 h of reperfusion. Liver histology was observed after 3 h of reperfusion.

RESULTS: The activities of ALT, AST, LDH, the level of MDA, and the expression of TNF-α, ICAM-1 mRNA in I/R, IP, and HHI-I group were significantly higher than those in SO group, but they were markedly lower in IP and HHI-I group than those in I/R group. The activities of ALT, AST, LDH in HHI-I group were significantly lower than those in IP group (ALT: 2378.8 ± 303.4 nkat/L vs 2840.6 ± 248.4 nkat/L; AST: 2887.2 ± 270.1 nkat/L vs 4567.6 ± 275.1 nkat/L; LDH: 10550.4 ± 710.1 nkat/L vs 12164.1 ± 735.1 nkat/L; all P < 0.05). As compared with that in the IP group, the level of MDA in HHI-I group was decreased at the 3^rd and 6^th hour (17.35 ± 1.39 nmol/g vs 21.66 ± 1.84 nmol/g, P < 0.05), and the mRNA expression of TNF-α and ICAM-1 were decreased (TNF-α: 0.54 ± 0.06 vs 0.78 ± 0.08; ICAM-1: 0.43 ± 0.03 vs 0.69 ± 0.11, both P < 0.01). The level of SOD in I/R, IP and HHI-I group was markedly lower than that in SO group (P < 0.05), but it was significantly higher in IP and HHI-I group than that in I/R group (P < 0.05). The SOD level in the animals received HHI-I was significantly increased in comparison with that in IP group (136.00 ± 12.50 nmol/g vs 124.70 ± 9.32 nmol/g, P < 0.05). Microscopy showed that liver injury in the HHI-I-treated animals and IP-treated animals were attenuated as compared with that in I/R group.

CONCLUSION: HHI-I and IP pretreatment can alleviate I/R-induced liver injury, and the former is superior to the latter. The protective mechanism of HHI-I may be associated with the improvement of liver microcirculation, elimination of tissue anoxia, transcription inhibition of cytokine and cell adhesion molecule such as TNF-α and ICAM-1, and decrease of neutrophil infiltration.

The effect of intraportal prostaglandin E1 on adhesion molecule expression, inflammatory modulator function, and histology in canine hepatic ischemia/reperfusion injury

BACKGROUND

Prostaglandin E1 (PGE1) is known to protect the liver from I/R, however, the mechanism of cytoprotection is not well understood. This study investigates the effect of intraportal infusion of PGE1 in a warm liver ischemia/reperfusion (I/R) model on cytokines, adhesion molecules and liver structure.

MATERIALS AND METHODS

Twenty dogs underwent laparotomy under general anesthesia. PGE1 (0.02 microg\kg\min) was perfused through the portal vein in the PGE1 group (n = 10), or a similar volume of Ringer's solution in the control group (n = 10) for 15 min. Liver ischemia was induced by hepatic artery and portal vein occlusion and PGE1 was infused via the portal vein for 60 min. The occlusion was released and PGE1 infusion recommenced for 30 min. Blood and liver biopsies were sampled at baseline, 60 min ischemia, and 30 min reperfusion and assessed for transaminases, cytokines, adhesion molecules, and electron microscopy.

RESULTS

PGE1 infusion significantly reduced transaminases TNF-alpha, sICAM-1, sP-selectin, and sE-selectin on ischemia and reperfusion. PGE1 reduced hepatocytic degeneration, portal and central ICAM-1 expression, central and sinusoidal VCAM-1 expression, portal and central P-selectin expression, and portal and sinusoidal E-selectin expression on reperfusion.

CONCLUSION

Intraportal PGE1 infusion reduced I/R injury and was associated with down-regulation of ICAM-1, VCAM-1, P-selectin, and E-selectin on reperfusion.

Beraprost sodium, a prostacyclin (PGI) analogue, ameliorates concanavalin A-induced liver injury in mice

BACKGROUND/AIMS

Prostacyclin (PGI(2)) is a potent mediator in the inflammatory and coagulation processes. The aim of this study was to test whether beraprost sodium, a PGI(2) analogue, could prevent experimental hepatic injury induced by concanavalin A (Con A), which is a model of fulminant hepatic failure.

METHODS

Beraprost (100 microg/kg) was administered intraperitoneally simultaneously with Con A (40 mg/kg) in C57B6J mice. Blood circulation in the liver was determined by laser-Doppler flowmetry. Plasma levels of alanine aminotransferase (ALT), tumor necrosis factor (TNF)-alpha, interferon (IFN)-gamma, and interleukin (IL)-6 were determined. Levels of TNF-alpha and IFN-gamma in culture supernatant of splenocytes were also determined.

RESULTS

Beraprost administration reduced the incidence of death following hepatic failure (76.5% vs. 29.4%, P<0.05). Plasma levels of ALT were significantly lower in the beraprost-treated group than in the control group, and in the former, there was concomitant suppression of the histological features of injury. Beraprost significantly increased hepatic blood flow volume in Con A-treated mice. Plasma levels of TNF-alpha and IFN-gamma were significantly reduced at 6 and 12 h after Con A injection, respectively, but the levels of IL-6 were increased at 6 h. In vitro, beraprost also suppressed Con A-induced TNF-alpha production in splenocytes, while it stimulated IFN-gamma production.

CONCLUSION

These findings imply that beraprost suppresses Con A-induced liver injury. These data also suggest that beraprost, which is clinically effective in treating pulmonary hypertension, may have therapeutic potential for preventing hepatic injury.