Modulation of liver oxidant-antioxidant system by ischemic preconditioning during ischemia／reperfusion injury in rats

AIM: To investigate effects of ischemic pre-conditioning on the liver endogenous oxidant-antioxidant system during ischemia/reperfusion injury. METHODS: Twenty-four male Sprague-Dawley rats were randomly divided into sham-operated (Sham), ischemia/ reperfusion (I/R), ischemic pre-conditioning plus ischemia/ reperfusion (IPC) groups. Serum ALT, AST and hyaluronic acid levels were assayed and pathologic alterations observed. Liver malondialdehyde (MDA) contents, endogenous antioxidant enzymes, superoxidase dismutase (SOD), catalase (CAT), gultathionine peroxidase (GSH-Px) activities, neutrophils accumulation marker, myeloperoxidase (MPO) activities were measured respectively. RESULTS: Compared with I/R group, sinusoidal endothelial cells as well as hepatocytes damages, as assessed biochemically and histochemically, were improved significantly in IPC group; neutrophils infiltration was also markedly reduced. In IPC group, liver peroxidation, as measured by MDA contents, was significantly decreased when compared with I/R group; endogenous antioxidant enzymes, SOD, CAT and GSH-Px activities were markedly higher than that in I/R group. CONCLUSION: Ischemic pre-conditioning exerts protective effects on both hepatic sinusoidal endothelial cells and hepatocytes during liver I/R injury. Its mechanisms may involve dimunition of neutrophils infiltration and modulation of the imbalance of endogenous oxidant-antioxidant system in the organism.     

NF-kB在大鼠肝缺血再灌注损伤中的活化及意义

目的探讨NFkB在肝缺血再灌注损伤过程中的作用。方法选择健康雌性Wistar大鼠24只,随机分为手术对照组,肝缺血90min组,肝缺血90min/再灌注120min组,每组8只。常规方法观察肝脏组织学改变,检测血清酶学水平和肝组织中髓过氧化物酶(MPO)含量,采用sABC免疫组织化学方法测定肝组织中NFkB的活化程度。结果手术对照组肝组织形态正常,无NFkB活化,肝功能酶学和MPO正常水平;缺血组动物肝细胞索排列紊乱,肝小叶变形,肝细胞和内皮细胞普遍水肿变性,NFkB呈中重度活化,血清酶学和MPO水平升高(P<0.01);肝缺血/再灌注组肝组织在缺血组改变基础上合并中央区局灶性肝细胞坏死,血窦内微血栓形成,汇管区中性粒细胞浸润,NFkB活化最为明显,血清酶学和MPO升高最为显著(P<0.01)。结论肝缺血再灌注时,NFkB被活化,使中性粒细胞组织浸润,对肝脏缺血再灌注损伤病理过程起到重要的作用。     

Effects of Wy14643 on hepatic ischemia reperfusion injury in rats

AIM： To investigate the effects and possible mechanisms of Wy14643 on hepatic ischemiareperfusion （I/R） injury in rats. METHODS： Thirty male Sprague-Dawley rats weighing 220-280 g were randomly divided into five experimental groups： sham group （G1, n = 6）： a sham operation was performed （except for liver I/R）, I/R-untreated group （G2, n = 6）： rats underwent liver ischemia for 90 min followed by reperfusion for 4h; and I/R ＋ Wy14643 groups （G3, G4, G5; n = 6）： after the same surgical procedure as in group 2, animals were pretreated with Wy14643 at the dose of 1, 5 and 10 mg/kg 1 h before ischemia, respectively. Hepatic ischemia-reperfusion （I/R） was induced by clamping blood supply to the left lateral and median lobes of the liver for 90 min, and atraumatic clamp was removed for 4 h reperfusion. Blood samples and liver tissues were obtained at the end of reperfusion to assess serum and hepatic tissue homogenate aminotransferase （ALT）, aspartate aminotransferase （AST）, myeloperoxidase （MPO）, serum interleukin- 1β（IL-1β） and tumor necrosis factor alpha （TNF-α）, as well as activity of superoxide dismutase （SOD） and content of malondialdehyde （MDA） in the hepatic tissue homogenate. RESULTS： Hepatic I/R induced a significant increase in the serum levels of ALT, AST, TNF-α, IL-1β and MPO, as well as the levels of ALT, AST and MDA in the liver tissue homogenate, which were reduced by pretreatment with Wy14643 at the dose of 1, 5 and 10 mg/kg, respectively. The activity of SOD in the liver tissue homogenate was decreased after hepatic I/R, which was enhanced by Wy14643 pretreatment. In addition, serum and liver tissue homogenate ALT and AST in the Wy14643 10 mg/kg group were lower than in the Wy14643 1 mg/kg and 5 mg/kg groups, respectively. CONCLUSION： Wy14643 pretreatment exerts significant protection against hepatic I/R injury in rats. The protective effects are possibly associated with enhancement of anti-oxidant and inhibition inflammation res     

Nuclear factor-kappaB decoy oligodeoxynucleotides attenuates ischemia/reperfusion injury in rat liver graft

AIM: To evaluate the protective effect of NF-kappaB decoy oligodeoxynucleotides (ODNs) on ischemia/reperfusion (I/R) injury in rat liver graft. METHODS: Orthotopic syngeneic rat liver transplantation was performed with 3 h of cold preservation of liver graft in University of Wisconsin solution containing phosphorothioated double-stranded NF-kappaB decoy ODNs or scrambled ODNs. NF-kappaB decoy ODNs or scrambled ODNs were injected intravenously into donor and recipient rats 6 and 1 h before operation, respectively. Recipients were killed 0 to 16 h after liver graft reperfusion. NF-kappaB activity in the liver graft was analyzed by electrophoretic mobility shift assay (EMSA). Hepatic mRNA expression of TNF-alpha, IFN-gamma and intercellular adhesion molecule-1 (ICAM-1) were determined by semiquantitative RT-PCR. Serum levels of TNF-alpha and IFN-gamma were measured by enzyme-linked immunosorbent assays (ELISA). Serum level of alanine transaminase (ALT) was measured using a diagnostic kit. Liver graft myeloperoxidase (MPO) content was assessed. RESULTS: NF-kappaB activation in liver graft was induced in a time-dependent manner, and NF-kappaB remained activated for 16 h after graft reperfusion. NF-kappaB activation in liver graft was significant at 2 to 8 h and slightly decreased at 16 h after graft reperfusion. Administration of NF-kappaB decoy ODNs significantly suppressed NF-kappaB activation as well as mRNA expression of TNF-alpha, IFN-gamma and ICAM-1 in the liver graft. The hepatic NF-kappaB DNA binding activity [presented as integral optical density (IOD) value] in the NF-kappaB decoy ODNs treatment group rat was significantly lower than that of the I/R group rat (2.16+/-0.78 vs 36.78+/-6.35 and 3.06+/-0.84 vs 47.62+/- 8.71 for IOD value after 4 and 8 h of reperfusion, respectively, P<0.001). The hepatic mRNA expression level of TNF-alpha, IFN-gamma and ICAM-1 [presented as percent of beta-actin mRNA (%)] in the NF-kappaB decoy ODNs treatment group rat was significantly lower than that of the I/R group rat (8.31+/-3.48 vs 46.37+/-10.65 and 7.46+/- 3.72 vs 74.82+/-12.25 for hepatic TNF-alpha mRNA, 5.58+/-2.16 vs 50.46+/-9.35 and 6.47+/-2.53 vs 69.72+/-13.41 for hepatic IFN-gamma mRNA, 6.79+/-2.83 vs 46.23+/-8.74 and 5.28+/-2.46 vs 67.44+/-10.12 for hepatic ICAM-1 mRNA expression after 4 and 8 h of reperfusion, respectively, P<0.001). Administration of NF-kappaB decoy ODNs almost completely abolished the increase of serum level of TNF-alpha and IFN-gamma induced by hepatic ischemia/reperfusion, the serum level (pg/mL) of TNF-alpha and IFN-gamma in the NF-kappaB decoy ODNs treatment group rat was significantly lower than that of the I/R group rat (42.7+/-13.6 vs 176.7+/-15.8 and 48.4+/-15.1 vs 216.8+/-17.6 for TNF-alpha level, 31.5+/-12.1 vs 102.1+/-14.5 and 40.2+/-13.5 vs 118.6+/-16.7 for IFN-gamma level after 4 and 8 h of reperfusion, respectively, P<0.001). Liver graft neutrophil recruitment indicated by MPO content and hepatocellular injury indicated by serum ALT level were significantly reduced by NF-kappaB decoy ODNs, the hepatic MPO content (A655) and serum ALT level (IU/L) in the NF-kappaB decoy ODNs treatment group rat was significantly lower than that of the I/R group rat (0.17+/-0.07 vs 1.12+/-0.25 and 0.46+/-0.17 vs 1.46+/-0.32 for hepatic MPO content, 71.7+/-33.2 vs 286.1+/-49.6 and 84.3+/-39.7 vs 467.8+/-62.3 for ALT level after 4 and 8 h of reperfusion, respectively, P<0.001). CONCLUSION: The data suggest that NF-kappaB decoy ODNs protects against I/R injury in liver graft by suppressing NF-kappaB activation and subsequent expression of proinflammatory mediators.     

Prophylaxis with carnosol attenuates liver injury induced by intestinal ischemia/reperfusion

AIM： To investigate the possible protective effects of carnosol on liver injury induced by intestinal ischemia reperfusion （I/R）.
METHODS： Rats were divided randomly into three experimental groups： sham, intestinal I/R and carnosol treatment （n = 18 each）. The intestinal I/R model was established by clamping the superior mesenteric artery for 1 h. In the carnosol treatment group, surgery was performed as in the intestinal I/R group, with intraperitoneal administration of 3 mg/kg carnosol 1 h before the operation. At 2, 4 and 6 h after reperfusion, rats were killed and blood, intestine and liver tissue samples were obtained. Intestine and liver histology was investigated. Serum levels of aspartate aminotransferase （AST）, alanine aminotransferase （ALT） and interleukin （IL）-6 were measured. Liver tissue superoxide dismutase （SOD） and myeloperoxidase （IvIPO） activity were assayed. The liver intercellular adhesion molecule-1 （ICAM-1） and nuclear factor κB （NF-κB） were determined by immunohistochemical analysis and western blot analysis.
RESULTS： Intestinal I/R induced intestine and liver injury, characterized by histological changes, as well as a significant increase in serum AST and ALT levels. The activity of SOD in the liver tissue decreased after I/R, which was enhanced by carnosol pretreatment. In addition, compared with the control group, carnosol markedly reduced liver tissue MPO activity and serum IL-6 level, which was in parallel with the decreased level of liver ICAI-1 and NF-κB expression.
CONCLUSION： Our results indicate that carnosol pretreatment attenuates liver injury induced by intestinal I/R, attributable to the antioxidant effect and inhibition of the NF-κB pathway.     

Hypertonic preconditioning prevents hepatocellular injury following ischemia/reperfusion in mice: a role for interleukin 10

Ischemia/reperfusion (I/R) of the liver occurs in many clinical scenarios including trauma, elective surgery, and transplantation. Events initiated by this process can lead to inflammation in the liver, culminating in local injury as well as distant organ dysfunction. Recent studies have suggested that hypertonic saline exerts anti-inflammatory effects, which may be beneficial in preventing organ injury. In the present study, we examine the effect of hypertonic saline on the development of liver inflammation following I/R in both rat and mouse models. Hypertonic pretreatment was shown to prevent liver enzyme release concomitant with a reduction in liver neutrophil sequestration. Hypertonic saline appeared to exert this effect by inhibiting liver tumor necrosis factor alpha (TNF-alpha) generation, an effect that culminated in reduced liver adhesion molecule expression. Hypertonic saline pretreatment was shown to augment liver interleukin 10 (IL-10) expression following I/R, as a potential mechanism underlying its anti-inflammatory effect. To examine the role of IL-10 in the protective effect of hypertonic saline on liver I/R injury, we used a murine model of I/R. In wild type mice, hypertonic pretreatment similarly prevented liver injury induced by I/R. However, in IL-10 knockout animals, hypertonic pretreatment was unable to prevent the liver enzyme release, TNF-alpha generation, or neutrophil sequestration induced by I/R. In conclusion, these findings define a novel mechanism responsible for the anti-inflammatory effects of hypertonic saline and also suggest a potential clinical role for hyperosmolar solutions in the prevention of liver injury associated with I/R.     

Reduced severity of liver ischemia/reperfusion injury following hepatic resection in humans is associated with enhanced intrahepatic expression of Th2 cytokines.

BACKGROUND: Based on previous studies in experimental models, pro-inflammatory Th1 cytokines (i.e. TNF-alpha and IFN-gamma) are thought to play a pathogenic role in hepatic ischemia/reperfusion injury, while anti-inflammatory Th2 cytokines (i.e. IL-4 and IL-10) have been associated with reduced liver disease severity. To test the relevance of these concepts in humans, cytokine expression profiles were characterized in liver biopsies from patients undergoing hepatic resection following intermittent portal clamping. METHODS: Twelve patients were analyzed for the intrahepatic expression of TNF-alpha, IFN-gamma, IL-4 and IL-10 before and about 90min after the last reperfusion. In addition, parameters of liver damage including sALT and serum levels of TNF-alpha were analyzed at 2, 24 and 48h after surgery. RESULTS: When compared with pre-reperfusion liver specimens, all post-reperfusion biopsies showed significantly increased levels of TNF-alpha and IFN-gamma mRNAs. Conversely IL-4 and IL-10 mRNA levels were significantly increased in only seven patients. A negative correlation was observed between Th2 cytokines (IL-4, IL-10) and ALT and serum levels of TNF-alpha. Furthermore, the presence of hepatic steatosis was significantly associated with lower intrahepatic contents of IL-4 and IL-10. CONCLUSIONS: The results suggest that the local early expression of Th2 cytokines may contribute to attenuate liver injury following ischemia reperfusion in humans. The early imbalance between pro- and anti-inflammatory cytokines seen in steatotic liver subjected to I/R could explain, at least partially, the decreased tolerance of steatotic livers to I/R injury.     

Protection of Veratrum nigrum L. var. ussuriense Nakai alkaloids against ischemia-reperfusion injury of the rat liver

AIM： TO investigate the protective effects and possible mechanisms of Veratrum nigrum L. var. ussuriense Nakai alkaloids （VnA） on hepatic ischemia/reperfusion （I/R） injury in rats.
METHODS： Forty male Wistar rats were randomly divided into four experimental groups （n = 10 in each）： （A） Control group （the sham operation group）; （8） I/R group （pretreated with normal saline）; （C） Small-dose （10 μg/kg） VnA pretreatment group; （D） Large-dose （20 μg/kg） VnA pretreatment group. Hepatic ischemia/ reperfusion （Hepatic I/R） was induced by occlusion of the portal vein and the hepatic artery for 90 min, followed by reperfusion for 240 min. The pretreatment groups were administered with VnA intraperitoneally, 30 min before surgery, while the control group and I/R group were given equal volumes of normal saline. Superoxide dismutase （SOD） activity, myeloperoxidase （MPO） activity and nitric oxide （NO） content in the liver tissue at the end of reperfusion were determined and liver function was measured. The expression of intercellular adhesion molecule-1 （ICAM-1） and E-selectin （ES） were detected by immunohistochemical examinations and Western blot analyses.
RESULTS： The results showed that hepatic I/R elicited a significant increase in the plasma levels of alanine aminotransferase （ALT： 74.53 ± 2.58 IU/L vs 1512.54 ± 200.76 IU/L, P 〈 0.01） and lactic dehydrogenase （LDH： 473.48 ± 52.17 IU/L vs 5821.53 ± 163.69 IU/L, P 〈 0.01）, as well as the levels of MPO （1.97 ± 0.11 U/g vs 2.57 ± 0.13 U/g, P 〈 0.01） and NO （69.37 ± 1.52 μmol/g protein vs 78.39 ± 2.28 μmol/g protein, P 〈 0.01） in the liver tissue, all of which were reduced by pretreatment with VnA, respectively （ALT： 1512.54 ± 200.76 IU/L vs 977.93 ± 89.62 IU/L, 909.81 ± 132.76 IU/L, P 〈 0.01, P 〈 0.01; LDH： 5821.53 ± 163.69 IU/L vs 3015.44 ± 253.01 IU/L, 2448.75 ± 169.4 IU/L, P 〈 0.01, P 〈 0.01; MPO： 2.57 ± 0.13 U/g vs 2.13 ± 0.13 U/g,     

Gender differences in hepatic ischemic reperfusion injury in rats are associated with endothelial cell nitric oxide synthase-derived nitric oxide

AIM: This study was designed to examine the hypothesis that gender differences in I/R injury are associated with endothelial cell nitric oxide synthase (eNOS)-derived nitric oxide (NO). METHODS: Wistar rats were randomized into seven experimental groups (12 animals per group). Except for the sham operated groups, all rats were subjected to total liver ischemia for 40 min followed by reperfusion. All experimental groups received different treatments 45 min before the laparotomy. For each group, half of the animals (six) were used to investigate the survival; blood samples and liver tissues were obtained in the remaining six animals after 3 h of reperfusion to assess serum NO, alanine aminotransferase (ALT) and TNF-α levels, liver tissue malondialdehyde (MDA) content, and severity of hepatic I/R injury. RESULTS: Basal serum NO levels in female sham operated (FS) group were nearly 1.5-fold of male sham operated (MS) group (66.7±11.0 μmol/L vs45.3μ10.1 μmol/L, P<0.01). Although serum NO levels decreased significantly after hepatic I/R (P<0.01, vs sham operated groups), they were still significantly higher in female rat (F) group than in male rat (M) group (47.8±8.6 μmol/L vs 23.8±4.7 μmol/L, P<0.01). Serum ALT and TNF-α levels, and liver tissue MDA content were significantly lower in F group than in M group (370.5±46.4 U/L, 0.99±0.11 μg/L and 0.57±0.10 μmol/g vs668.7±78.7 U/L, 1.71±0.18μg/L and 0.86±0.11 μmol/g, respectively, P<0.01). I/R induced significant injury to the liver both in M and F groups (P<0.01 vs sham operated groups). But the degree of hepatocyte injury was significantly milder in F group than in M group (P<0.05 and P<0.01). The median survival time was six days in F group and one day in M group. The overall survival rate was significantly higher in F group than in M group (P<0.05). When compared with male rats pretreated with saline (M group), pretreatment of male rats with 17-β-estradiol (E2) (M+E2 group) significantly increased serum NO levels and significantly decreased serum ALT and TNF-α levels, and liver tissue MDA content after I/R (P<0.01). The degree of hepatocyte injury was significantly decreased and the overall survival rate was significantly improved in M+E2 group than in M group (P<0.01 and P<0.05). The NOS inhibitor Nw-nitro-L-arginine methyl ester (L-NAME) treatment could completely abolish the protective effects of estrogen in both male and female rats. CONCLUSION: The protective effects afforded to female rats subjected to hepatic I/R are associated with eNOS-derived NO.     

2-Mercaptoethane sulfonate (MESNA) protects against biliary obstruction-induced oxidative damage in rats.

The aim of this study was to assess the antioxidant and antifibrotic effects of chronic administration of 2-mercaptoethane sulfonate (MESNA) on oxidative liver damage and fibrosis induced by biliary obstruction in rats. Liver fibrosis was induced in male Wistar albino rats by bile duct ligation and scission (BDL). MESNA (150mg/kg, i.p.) or saline was administered for 28 days. At the end of the experiment, rats were killed by decapitation. Serum aspartate aminotransferase (AST), and alanine aminotransferase (ALT) levels were determined to assess liver function. Tumor necrosis factor-alpha (TNF-alpha) and lactate dehidrogenase (LDH) were also assayed in serum samples. Liver tissues were taken for determination of the free radicals, hepatic malondialdehyde (MDA) levels, an end product of lipid peroxidation; glutathione (GSH) levels, a key antioxidant; myeloperoxidase (MPO) activity, as an indirect index of neutrophil infiltration. Hepatic collagen content, as a fibrosis marker was also determined. Serum AST, ALT, LDH and TNF-alpha levels were elevated in the BDL group as compared to control group, while this increase was significantly decreased by MESNA treatment. BDL caused a significant (p<0.05-0.001) decrease in GSH levels while MDA levels and MPO activity were increased in the liver tissue. These changes were reversed by MESNA treatment. Collagen contents of the liver tissue was increased by BDL (p<0.001), and reversed back to the control levels with MESNA. Since MESNA administration alleviated the BDL-induced oxidative injury of the liver and improved the hepatic functions, it seems likely that MESNA with its antioxidant and antifibrotic properties, may be of potential therapeutic value in protecting the liver fibrosis and oxidative injury due to biliary obstruction.     

Ischemic preconditioning affects interleukin release in fatty livers of rats undergoing ischemia/reperfusion

The present study evaluates the effect of ischemic preconditioning on interleukin-1 (IL-1) and interleukin-10 (IL-10) generation following hepatic ischemia/reperfusion (I/R) in normal and steatotic livers as well as the role of nitric oxide (NO) in this process. Increased IL-1beta and IL-10 levels were observed in normal livers after I/R. Steatotic livers showed higher IL-1beta levels than normal livers, and IL-10 at control levels. The injurious role of IL-1beta and the benefits of IL-10 on hepatic I/R injury was shown with the use of IL-1 receptor antagonist (IL-1ra), anti-IL-10 polyclonal antibody against IL-10 (anti-IL-10) and exogenous IL-10. The effective dose of these treatments was different in both types of livers. Preconditioning prevented IL-1beta release and increased IL-10 generation after I/R in normal and steatotic livers. IL-1beta or anti-IL-10 pretreatments reversed the benefits of preconditioning. IL-1beta action inhibition in a preconditioned group that was pretreated with anti-IL-10 did not modify the benefits of preconditioning. In addition, anti-IL-10 pretreatment in the preconditioned group resulted in IL-1beta levels comparable to those observed after I/R. NO inhibition eliminated the benefits of preconditioning on IL-10 release, IL-1beta levels, and hepatic injury. In conclusion, preconditioning, through IL-10 overproduction, inhibits IL-1beta release and the ensuing hepatic I/R injury in normal and steatotic livers. IL-10 generation induced by preconditioning could be mediated by NO.     

Effect of nuclear factor kappa B on intercellular adhesion molecule-1 expression and neutrophil infiltration in lung injury induced by intestinal ischemia/reperfusion in rats

AIM:To investigate the role of nuclear factor kappa B(NF-κB) in the pathogenesis of lung injury induced byintestinal ischemia/reperfusion (I/R),and its effect onintercellular adhesion molecule-1 (ICAM-1) expressionand neutrophil infiltration.METHODS:Twenty-four Wistar rats weredivided randomly into control,I/R and pyrrolidinedithiocarbamate (PDTC) treatment groups,n=8 ineach.I/R group and PDTC treatment group receivedsuperior mysenteric artery (SMA) occluding for 1 h andreperfusion for 2 h.PDTC group was administrated withintraperitoneal injection of 2% 100 mg/kg PDTC 1 hbefore surgery.Lung histology and bronchia alveoluslung fluid (BALF) protein were assayed.Serum IL-6,lungmalondialdehyde (MDA) and myeloperoxidase (MPO) aswell as the expression level of NF-κB and ICAM-1 weremeasured.RESULTS:Lung injury induced by intestinal I/R,wascharacterized by edema,hemorrhage and neutrophilinfiltration as well as by the significant rising of BALFprotein.Compared to control group,the levels of serumIL-6 and lung MDA and MPO increased significantly in I/Rgroup (P=0.001).Strong positive expression of NF-κBp65 and ICAM-1 was observed.After the administrationof PDTC,the level of serum IL-6,lung MDA and MPOas well as NF-κB and ICAM-1 decreased significantly(P<0.05) when compared to I/R group. CONCLUSION:The activation of NF-kB plays animportant role in the pathogenesis of lung injury inducedby intestinal I/R through upregulating the neutrophilinfiltration and lung ICAM-1 expression.PDTC as aninhibitor of NF-kB can prevent lung injury induced byintestinal I/R through inhibiting the activity of NF-kB.     

TNF-alpha but not IL-1alpha is correlated with PGE1-dependent protection against acute D-galactosamine-induced liver injury.

BACKGROUND: Prostaglandin E1 (PGE1) treatment of humans and rodents during acute hepatic failure ameliorates different parameters of hepatic dysfunction. PURPOSE: To investigate whether prevention of acute liver injury induced by D-galactosamine (D-GalN) with preadministration of PGE1 is correlated with a change in the concentration of two proinflammatory cytokines, as tumour necrosis factor-alpha (TNF-alpha) and interleukin (IL)-1alpha, and/or nitrite+nitrate (NOx), as nitric oxide-related end products in serum. RESULTS: D-GalN significantly increased alanine aminotransferase (ALT) and TNF-alpha concentration in serum 5 and 10 mins, respectively, after treatment compared with the control group (P< or =0.05). D-GalN did not change the IL-1alpha concentration at any time during the study. Preadministration of PGE1 to D-GalN-treated rats significantly reduced the ALT content and increased significantly the TNF-alpha concentration in serum 1, 2.5, 5 and 10 mins after D-GalN treatment compared with the D-GalN group (P< or =0.05). Nitric oxide was not involved in either the toxic effect due to D-GalN or the protection observed with PGE1 against D-GalN toxicity. CONCLUSIONS: Acute liver injury induced by D-GalN is correlated with an increased TNF-alpha release. Preadministration of PGE1 to D-GalN-treated rats exerted a priming effect on inflammatory cells to release enhanced levels of TNF-alpha but not IL-1alpha. These findings indicate that stimulation of TNF-alpha release may be involved in the acute D-GalN-induced liver injury and also in PGE1 protection from hepatotoxicity in clinical and experimental studies.     

Protective effect of curcumin against liver warm ischemia/reperfusion injury in rat model is associated with regulation of heat shock protein and antioxidant enzymes

AIM： To investigate the hypothesis that the protective effects of curcumin in hepatic warm ischemia/reperfusion （I/R） injury are associated with increasing heat shock protein 70 （Hsp70） expression and antioxidant enzyme activity. METHODS： Sixty Sprague-Dawley male rats were randomly divided into sham, I/R, C ＋ I/R groups. The model of reduced-size liver warm ischemia and reperfusion was used. Curcumin （50 mg/kg） was administered by injection through a branch of superior mesenteric vein at 30 min before ischemia in C ＋ I/R group. Five rats were used to investigate the survival during 1 wk after operation in each group. Blood samples and liver tissues were obtained in the remaining animals after 3, 12, and 24 h of reperfusion to assess serum alanine aminotransferase （ALT）, aspartate aminotransferase （AST）, liver tissue NO2- ＋ NO3-, malondialdehyde （MDA） content, superoxide dismutase （SOD）, catalase （CAT）, nitricoxide synthase （NOS） and myeloperoxidase （MPO） activity, HspT0 expression and apoptosis ratio. RESULTS： Compared with I/R group, curcumin pretreatment group showed less ischemia/reperfusioninduced injury. CAT and SOD activity and Hsp70 expression increased significantly. A higher rate of apoptosis was observed in I/R group than in C ＋ I/R group, and a significant increase of MDA, NO2^- ＋ NO3^- and MPO level in liver tissues and serum transaminase concentration was also observed in I/R group compared to C ＋ I/R group. Curcumin also decreased the activity of inducible NO synthase （iNOS） in liver after reperfusion,but had no effect on the level of endothelial NO synthase （eNOS） after reperfusion in liver. The 7 d survival rate was significantly higher in C ＋ I/R group than in I/R group. CONCLUSION： Curcumin has protective effects against hepatic I/R injury. Its mechanism might be related to the overexpression of Hsp70 and antioxidant enzymes.     

Effect of nuclear factor kappa B on intercellular adhesionrnolecule-1 expression and neutrophil infiltration in lung injury induced by intestinal ischemia/reperfusion in rats

AIM: To investigate the role of nuclear factor kappa B(NF-κB) in the pathogenesis of lung injury induced by intestinal ischemia/reperfusion (I/R), and its effect on intercellular adhesion molecule-1 (ICAM-1) expression and neutrophil infiltration.METHODS: Twenty-four Wistar rats were divided randomly into control, I/R and pyrrolidine dithiocarbamate (PDTC) treatment groups, n = 8 in each. I/R group and PDTC treatment group received superior mysenteric artery (SMA) occluding for 1 h and reperfusion for 2 h. PDTC group was administrated with intraperitoneal injection of 2% 100 mg/kg PDTC 1 h before surgery. Lung histology and bronchia alveolus lung fluid (BALF) protein were assayed. Serum IL-6, lung malondialdehyde (MDA) and myeloperoxidase (MPO) as well as the expression level of NF-κB and ICAM-1 were measured.RESULTS: Lung injury induced by intestinal I/R, was characterized by edema, hemorrhage and neutrophil infiltration as well as by the significant rising of BALF protein. Compared to control group, the levels of serum IL-6 and lung MDA and MPO increased significantly in I/R group (P=0.001). Strong positive expression of NF-κB p65 and ICAM-1 was observed. After the administration of PDTC, the level of serum IL-6, lung MDA and MPO as well as NF-κB and ICAM-1 decreased significantly(P＜ 0.05) when compared to I/R group.CONCLUSION: The activation of NF-κB plays an important role in the pathogenesis of lung injury induced by intestinal I/R through upregulating the neutrophil infiltration and lung ICAM-1 expression. PDTC as an inhibitor of NF-κB can prevent lung injury induced by intestinal I/R through inhibiting the activity of NF-κB.     

Grape seed extract reduces oxidative stress and fibrosis in experimental biliary obstruction

BACKGROUND AND AIM: The aim of this study was to assess the protective effect of grape seed extract (GSE) against oxidative liver injury and fibrosis induced by biliary obstruction in rats. METHODS: Wistar albino rats were divided into four groups; control (C), GSE-treated, bile duct ligated (BDL), and BDL and GSE-treated (BDL + GSE) groups. GSE was administered at a dose of 50 mg/kg a day orally for 28 days. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) levels were determined to assess liver function and tissue damage, respectively. Tumor necrosis factor-alpha (TNF-alpha) and antioxidant capacity (AOC) were assayed in plasma samples. Liver tissues were taken for determination of the hepatic malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity and collagen content. Production of reactive oxidants was monitored by chemiluminescence (CL) assay. RESULTS: Serum AST, ALT, LDH and plasma TNF-alpha were elevated in the BDL group as compared to the control group and were significantly decreased with GSE treatment. Plasma AOC and hepatic GSH level, depressed by BDL, was elevated back to the control level in the GSE-treated BDL group. Increases in tissue MDA level, MPO activity and collagen content due to BDL were also attenuated by GSE treatment. Furthermore, luminol and lucigenin CL values in the BDL group increased dramatically compared to the control and were reduced by GSE treatment. DISCUSSION: These results suggest that GSE protects the liver from oxidative damage following bile duct ligation in rats. This effect possibly involves the inhibition of neutrophil infiltration and lipid peroxidation; thus, restoration of oxidant and antioxidant status in the tissue.     

Interleukin-37 reduces liver inflammatory injury via effects on hepatocytes and non-parenchymal cells

Background and Aim: The purpose of the present study was to determine the effects of interleukin-37 (IL-37) on liver cells and on liver inflammation induced by hepatic ischemia/reperfusion (I/R). Methods: Mice were subjected to I/R. Some mice received recombinant IL-37 (IL-37) at the time of reperfusion. Serum levels of alanine aminotransferase, and liver myeloperoxidase content were assessed. Serum and liver tumor necrosis factor-α (TNF-α), macrophage inflammatory protein-2 (MIP-2) and keratinocyte chemokine (KC) were also assessed. Hepatic reactive oxygen species (ROS) levels were assessed. For in vitro experiments, isolated hepatocytes and Kupffer cells were treated with IL-37 and inflammatory stimulants. Cytokine and chemokine production by these cells were assessed. Primary hepatocytes underwent induced cell injury and were treated with IL-37 concurrently. Hepatocyte cytotoxicity and Bcl-2 expression were determined. Isolated neutrophils were treated with TNF-α and IL-37 and neutrophil activation and respiratory burst were assessed. Results: IL-37 reduced hepatocyte injury and neutrophil accumulation in the liver after I/R. These effects were accompanied by reduced serum levels of TNF-α and MIP-2 and hepatic ROS levels. IL-37 significantly reduced MIP-2 and KC productions from lipopolysaccharide-stimulated hepatocytes and Kupffer cells. IL-37 significantly reduced cell death and increased Bcl-2 expression in hepatocytes. IL-37 significantly suppressed TNF-α-induced neutrophil activation. Conclusions: IL-37 is protective against hepatic I/R injury. These effects are related to the ability of IL-37 to reduce proinflammatory cytokine and chemokine production by hepatocytes and Kupffer cells as well as having a direct protective effect on hepatocytes. In addition, IL-37 contributes to reduce liver injury through suppression of neutrophil activity.     

Role of Kupffer cells in acute hemorrhagic necrotizing pancreatitis-associated lung injury of rats

AIM:To investigate the role of Kupffer cells(KCs)inacute hemorrhagic necrotizing pancreatitis-associatedlung injury(AHNP-LI).METHODS:Forty-two rats were allocated to fourgroups[sham operation,AHNP model,gadoliniumchloride(GdCl_3)pretreatment,GdCl_3 control].In GdCl_3pretreatment group,GdCl_3 was administered by caudalvein injection 24 h before the AHNP model induction.Blood from the iliac artery,alveolar macrophages andtissues from the pancreas and lung,were collected insix animals per group 3 and 6 h after acute pancreatitisinduction.TNF-α,IL-1 of serum,myeloperoxidase(MPO)of lung tissue,NF-kB activation of alveolar macrophageswere detected.Serum AST and ALT in sham operationgroup and GdCl_3 control group were tested.In addition,histopathological changes of the pancreas and lung wereobserved under light microscope.RESULTS:MPO of lung tissue and TNF-α,IL-1 levelsof serum were all reduced significantly in GdCl_3pretreatment group compared to those in AHNP group(P<0.01).NF-kB activation of alveolar macrophageswas also attenuated significantly in GdCl_3 pretreatmentgroup compared to that in AHNP group(P<0.01).Thepathological injury of the lung was ameliorated obviouslyin GdCl_3 pretreatment group compared to that in AHNPgroup.Nevertheless,the serum amylase level did notreduce and injury of the pancreas was not prevented inGdCl_3 pretreatment group.CONCLUSION:Pulmonary injury induced by AHNPis mediated by KC activation and AHNP-LI can be significantly ameliorated by pretreatment with GdCl_3 andKCs play a vital role in AHNP-LI.     

内毒素预适应减轻急性肝功能衰竭中热休克蛋白27的作用

目的研究热休克蛋白27（HSP27）介导内毒素（LPS）预适应减轻急性肝功能衰竭（ALF）的作用机制。方法实验动物为雄性C57BL/6小鼠。将小鼠分为5组,对照组为正常C57BL/6小鼠;肝功能衰竭组小鼠以LPS10μg/kg＋D-半乳糖胺700 mg/kg,用1 mL0.9%氯化钠溶液溶解后腹腔内注射,建立急性肝功能衰竭的模型;LPS预处理组小鼠经LPS预适应24 h后,建立急性肝功能衰竭的模型;HSP27干扰组小鼠和转染对照组小鼠分别以尾静脉注射包装有干扰HSP27表达的短发夹RNA的重组腺病毒以及对照空病毒,成功干扰HSP27表达后,经LPS预处理,建立急性肝功能衰竭模型。通过比较各组ALT和AST水平,评价肝组织病理损伤程度,以及检测肝组织内TNF-α、IL-6mRNA水平,观察HSP27对LPS预适应减轻急性肝功能衰竭的影响。结果 LPS预适应可明显减轻Galn/LPS所致的肝损伤,干扰HSP27的表达后,小鼠血清ALT和AST明显升高,肝组织病理损伤和炎性反应加重（P〈0.05）。下调HSP27的表达水平后,LPS预适应的保护作用几乎完全消失。结论 LPS预适应可以减轻小鼠的急性肝损伤,HSP27在这一效应中发挥重要作用。