A novel soluble beta-glucan salecan protects against acute alcohol-induced hepatotoxicity in mice

This investigation was designed to determine the effect of a novel soluble beta-glucan salecan on acute alcohol-induced hepatic injury in mice. Mice were given salecan (15 or 30 mg/kg) or PBS for 4 d. Ethanol (6 g/kg) was administered orally 1 h after the last injection. The animals were sacrificed at 10 h after alcohol administration. Pretreatment with salecan significantly ameliorated the hepatic damage induced by ethanol, as evidenced by markedly reduced serum aminotransferase activities and hepatocyte steatosis. Salecan administration remarkably alleviated the formation of thiobarbituric acid-reactive substances and counteracted glutathione depletion. The mRNA level of peroxisome proliferator activated receptor alpha, a major gene responsible for fatty acid oxidation, was significantly increased after salecan pretreatment. The expression of diacylglycerol acyltransferase 1, an important gene responsible for triacylglycerol synthesis, was markedly decreased after salecan was administrated. These findings suggest that salecan might represent a novel protective strategy against alcoholic liver injury.     

Dietary salecan reverts partially the metabolic gene expressions and NMR-based metabolomic profiles from high-fat-diet-induced obese rats

Previous studies suggest that dietary salecan (a water-soluble β-glucan) effectively reduces high-fat-diet-induced adiposity through disturbing bile-acid-promoted emulsification in mice. However, the effects of salecan on metabolic genes and metabolites involved in lipid accumulation are mostly unknown. Here, we confirmed that dietary 3% and 6% salecan for 4 weeks markedly decreased fat accumulation in liver and adipose tissue in high-fat-diet rats, displaying a decrease in mRNA levels of SREBP1-C, FAS, SCD1 and ACC1 involved in de novo lipogenesis and a reduction of levels of GPAT1, DGAT1 and DGAT2 related to triglyceride synthesis. Dietary salecan also increased the mRNA levels of PPARα and CYP7A1, which are related to fatty acid oxidation and cholesterol decomposition, respectively. In the ¹H nuclear magnetic resonance metabolomic analysis, both the serum and liver metabolite profiles differed among the control groups, and the metabolic profiles of the salecan groups were shifted toward that of the low-fat-diet group. Metabolites analysis showed that salecan significantly increased hepatic glutathione and betaine levels which are related to regulation of cellular reactive oxygen species. These data demonstrate that dietary salecan not only disturbed fat digestion and absorption but also influenced lipid accumulation and metabolism in diet-induced obesity.     

Liver I/R injury is improved by the arginase inhibitor, N(omega)-hydroxy-nor-L-arginine (nor-NOHA)

Liver ischemia-reperfusion (I/R) injury is associated with profound arginine depletion due to arginase release from injured hepatocytes. The purpose of this study was to determine whether arginase inhibition with N(omega)-hydroxy-nor-l-arginine (nor-NOHA) would increase circulating arginine levels and decrease hepatic damage during liver I/R injury. The effects of nor-NOHA were initially tested in normal animals to determine in vivo toxicity. In the second series of experiments, orthotopic syngeneic liver transplantation (OLT) was performed after 18 h of cold ischemia time in Lewis rats. Animals were given nor-NOHA (100 mg/kg) or saline before and after graft reperfusion. In normal animals treated with nor-NOHA, there were no histopathological changes to organs, liver enzymes, serum creatinine, or body weight. In the OLT model, animals treated with saline exhibited markedly elevated serum transaminases and circulating arginase protein levels. Nor-NOHA administration blunted the increase in serum arginase activity by 80% and preserved serum arginine levels at 3 h after OLT. Nor-NOHA treatment reduced post-OLT serum liver enzyme release by 50%. Liver histology (degree of necrosis) in nor-NOHA-treated animals was markedly improved compared with the saline-treated group. Furthermore, use of the arginase inhibitor nor-NOHA did not influence polyamine synthesis owing to the decrease in ornithine levels. Arginase blockade represents a potentially novel strategy to combat hepatic I/R injury associated with liver transplantation.     

Influence of small doses of various drug vehicles on acetaminophen-induced liver injury

The biological effects of drug vehicles are often overlooked, often leading to artifacts in acetaminophen-induced liver injury assessment. Therefore, we decided to investigate the effect of dimethylsulfoxide, dimethylformamide, propylene glycol, ethanol, and Tween 20 on acetaminophen-induced liver injury. C57BL/6 male mice received a particular drug vehicle (0.6 or 0.2 mL/kg, i.p.) 30 min before acetaminophen administration (300 mg/kg, i.p.). Control mice received vehicle alone. Liver injury was assessed by measuring the concentration of alanine aminotransferase in plasma and observing histopathological changes. The level of reduced glutathione (GSH) was assessed by measuring total nonprotein hepatic sulfhydrils. Dimethylsulfoxide and dimethylformamide (at both doses) almost completely abolished acetaminophen toxicity. The higher dose of propylene glycol (0.6 mL/kg) was markedly protective, but the lower dose (0.2 mL/kg) was only slightly protective. These solvents also reduced acetaminophen-induced GSH depletion. Dimethylformamide was protective when given 2 h before or 1 h after acetaminophen administration, but was ineffective if given 2.5 h after acetaminophen. Ethanol at the higher dose (0.6 mL/kg) was partially protective, whereas ethanol at the lower dose (0.2 mL/kg) as well as Tween 20 at any dose had no influence. None of the vehicles (0.6 mL/kg) was hepatotoxic per se, and none of them was protective in a model of liver injury caused by D-galactosamine and lipopolysaccharide.     

Insulin protects against hepatic damage postburn

Burn injury causes hepatic dysfunction associated with endoplasmic reticulum (ER) stress and induction of the unfolded protein response (UPR). ER stress/UPR leads to hepatic apoptosis and activation of the Jun-N-terminal kinase (JNK) signaling pathway, leading to vast metabolic alterations. Insulin has been shown to attenuate hepatic damage and to improve liver function. We therefore hypothesized that insulin administration exerts its effects by attenuating postburn hepatic ER stress and subsequent apoptosis. Male Sprague Dawley rats received a 60% total body surface area (TBSA) burn injury. Animals were randomized to receive saline (controls) or insulin (2.5 IU/kg q. 24 h) and euthanized at 24 and 48 h postburn. Burn injury induced dramatic changes in liver structure and function, including induction of the ER stress response, mitochondrial dysfunction, hepatocyte apoptosis, and up-regulation of inflammatory mediators. Insulin decreased hepatocyte caspase-3 activation and apoptosis significantly at 24 and 48 h postburn. Furthermore, insulin administration decreased ER stress significantly and reversed structural and functional changes in hepatocyte mitochondria. Finally, insulin attenuated the expression of inflammatory mediators IL-6, MCP-1, and CINC-1. Insulin alleviates burn-induced ER stress, hepatocyte apoptosis, mitochondrial abnormalities, and inflammation leading to improved hepatic structure and function significantly. These results support the use of insulin therapy after traumatic injury to improve patient outcomes.     

FTY720 suppresses liver tumor metastasis by reducing the population of circulating endothelial progenitor cells

Background

Surgical procedures such as liver resection and liver transplantation are the first-line treatments for hepatocellular carcinoma (HCC) patients. However, the high incidence of tumor recurrence and metastasis after liver surgery remains a major problem. Recent studies have shown that hepatic ischemia-reperfusion (I/R) injury and endothelial progenitor cells (EPCs) contribute to tumor growth and metastasis. We aim to investigate the mechanism of FTY720, which was originally applied as an immunomodulator, on suppression of liver tumor metastasis after liver resection and partial hepatic I/R injury.

Methodology/Principal Findings

An orthotopic liver tumor model in Buffalo rat was established using the hepatocellular carcinoma cell line McA-RH7777. Two weeks after orthotopic liver tumor implantation, the rats underwent liver resection for tumor-bearing lobe and partial hepatic I/R injury. FTY720 (2 mg/kg) was administered through the inferior caval vein before and after I/R injury. Blood samples were taken at days 0, 1, 3, 7, 14, 21 and 28 for detection of circulating EPCs (CD133+CD34+). Our results showed that intrahepatic and lung metastases were significantly inhibited together with less tumor angiogenesis by FTY720 treatment. The number of circulating EPCs was also significantly decreased by FTY720 treatment from day 7 to day 28. Hepatic gene expressions of CXCL10, VEGF, CXCR3, CXCR4 induced by hepatic I/R injury were down-regulated in the treatment group.

Conclusions/Significance

FTY720 suppressed liver tumor metastasis after liver resection marred by hepatic I/R injury in a rat liver tumor model by attenuating hepatic I/R injury and reducing circulating EPCs.     

Astringinin-mediated attenuation of the hepatic injury following trauma-hemorrhage

Although astringinin administration under adverse circulatory conditions is known to be protective, the mechanism by which astringinin produces the salutary effects remains unknown. We hypothesize that astringinin administration in males following trauma-hemorrhage decreases cytokine production and protects against hepatic injury. Male Sprague-Dawley rats underwent trauma-hemorrhage (mean blood pressure: 40 mmHg for 90 min, then resuscitation). Different doses of astringinin (0.01, 0.03, 0.1, 0.3 mg/kg of body weight) or vehicle were administered intravenously during resuscitation. Concentrations of plasma aspartate aminotransferase (AST) with alanine aminotransferase (ALT) and various hepatic parameters were measured (n = 8 rats/group) at 24 h after resuscitation. One-way ANOVA and Tukey testing were used for statistical analysis. Trauma-hemorrhage significantly increased plasma AST and ALT levels at 24 h postresuscitation; there was a dose-related benefit when astringinin was administered at doses of 0.01 to 0.3 mg/kg. In astringinin-treated (0.3 mg/kg) rats subjected to trauma-hemorrhage, there were significant improvements in liver myeloperoxidase (MPO) activity (237.80 +/- 45.89 vs. 495.95 +/- 70.64 U/mg protein, P < 0.05), interleukin-6 (IL-6) levels (218.54 +/- 34.52 vs. 478.60 +/- 76.21 pg/mg protein, P < 0.05), cytokine-induced neutrophil chemoattractant (CINC)-1 (88.32 +/- 20.33 vs. 200.70 +/- 32.68 pg/mg protein, P < 0.05), CINC-3 (110.83 +/- 26.63 vs. 290.14 +/- 76.82 pg/mg protein, P < 0.05) and intercellular adhesion molecule (ICAM)-1 concentrations (1,868.5 +/- 211.5 vs. 3,645.0 +/- 709.2 pg/mg protein, P < 0.05), as well as in histology. Results show that astringinin significantly attenuates proinflammatory responses and hepatic injury after trauma-hemorrhage. In conclusion, the salutary effects of astringinin administration on attenuation of hepatic injury following trauma-hemorrhage are likely due to reduction of pro-inflammatory mediator levels.     

Differential patterns of cocaine-induced organ toxicity in murine heart versus liver

To determine cocaine's toxicity in different organs, BALB/c mice were intraperitoneally injected daily for 15 days with either saline or cocaine: 10 mg/kg, 30 mg/kg, or 60 mg/kg. Cardiac function, hepatic pathophysiology, heart and liver apoptosis, and tumor necrosis factor (TNF-alpha) levels were analyzed. After administration of cocaine, cardiac function decreased. Inflammatory cell infiltration and eosinophilic contraction bands were visible in the hearts of mice treated with 60mg/kg cocaine. Moreover, histopathology demonstrated that cocaine caused hepatic necrosis. TdT-mediated dUTP nick end-labeling (TUNEL) staining and DNA ladder analysis indicated that cocaine caused apoptosis in both the heart and liver. Moreover, immunoassay showed that TNF-alpha levels significantly increased in the heart and liver with cocaine administration. However, our RT-PCR study showed that there was no significant difference in either the heart or liver in the levels of mRNA for TNF-alpha between cocaine-treated and saline control mice. The present study demonstrated that cocaine is toxic to multiple organs, and at low dose can induce hepatic damage without gross pathological injury to the heart. The results suggest that the liver is more sensitive than the heart to cocaine toxicity, and induction of apoptosis or TNF-alpha elevation may be a common mechanism responsible for cocaines toxicity.     

The anti-inflammatory and anti-apoptotic effects of nesfatin-1 in the traumatic rat brain

Nesfatin-1 has been demonstrated to possess anti-inflammatory and anti-apoptotic effects in the rat brain with subarachnoid hemorrhage. The study was designed to investigate the influence of nesfatin-1 on inflammatory responses and neuronal cell apoptosis after traumatic brain injury. Wistar rats were subjected to 5, 10 or 20 μg/kg of nesfatin-1 at designed time points (0.5, 2, 4 or 8h after head trauma) intraperitoneally. Rats were sacrificed at hours 2, 6 and 12, as well as day 1, 2, 3 and 5 after head trauma. The administration of 10 or 20 μg/kg of nesfatin-1 at hour 0.5 after head trauma could significantly suppress gene expressions of nuclear factor kappa-B, lessen concentrations of tumor necrosis factor-alpha, interleukin-1beta and interleukin-6, diminish caspase-3 activity as well as reduce number of apoptotic neuronal cells in traumatic rat brain tissues (P<0.05), but the administration of 5 μg/kg of nesfatin-1 not (P>0.05). Moreover, 20 μg/kg nesfatin-1 also significantly suppressed the inflammation and neuronal cell apoptosis when applied 2, 4 or 8h after head trauma. However, a clear concentration-response or time-response relationship was not found. These findings suggest that nesfatin-1 may inhibit nuclear factor kappa-B-dependent inflammatory responses, and lessen caspase-3-mediated neuronal cell apoptosis after traumatic brain injury in rats.     

Role of caspases in acetaminophen-induced liver injury

The mode of cell death after acetaminophen (AAP) overdose is controversially discussed. A recent study reported a protective effect of the pancaspase inhibitor Z-VAD-fmk against AAP toxicity in vivo but the mechanism of protection remained unclear. Therefore, the objective of this investigation was to assess if Z-VAD-fmk or the low doses of dimethyl sulfoxide (DMSO) used as solvent were responsible for the protection. Treatment with 10 mg/kg Z-VAD-fmk or diluted DMSO (0.25 ml/kg) for 15 min before but not 2.5 h after AAP prevented the oxidant stress (hepatic glutathione disulfide content; nitrotyrosine staining), DNA fragmentation (anti-histone ELISA, TUNEL assay) and liver injury (plasma ALT activities) at 6 h after administration of 300 mg/kg AAP. Even a lower dose (0.1 ml/kg) of DMSO was partially effective. DMSO pretreatment also attenuated the initial decline in hepatic glutathione levels. On the other hand, 10 microM Z-VAD-fmk was unable to prevent AAP-induced cell death in primary cultured mouse hepatocytes. We conclude that Z-VAD-fmk does not protect against AAP-induced liver injury and, therefore, caspases are not involved in the mechanism of AAP-induced liver injury. In contrast, the protection in vivo is caused by the diluted DMSO, which is used to solubilize the inhibitor Z-VAD-fmk. The results emphasize that even very low doses of DMSO, which are generally necessary to dissolve water-insoluble inhibitors, can have a profound impact on the toxicity of drugs and chemicals when metabolic activation is a critical aspect of the mechanism of cell injury.     

A comparative study of the inhibition of hepatic aldehyde dehydrogenases in the rat by methyltetrazolethiol, calcium carbimide, and disulfiram

Methyltetrazolethiol (1-methyl-5-mercapto-1,2,3,4-tetrazole, MTT) is a heterocyclic substituent of the cephalosporin antibiotics, cefamandole, cefoperazone, and moxalactam. Pretreatment of rats with MTT has been reported to increase blood acetaldehyde concentration after ethanol administration. The time course of MTT-induced inhibition of hepatic aldehyde dehydrogenases (ALDH) was determined in adult, male Sprague-Dawley rats in comparison with the hepatic ALDH inhibition induced by calcium carbimide (calcium cyanamide, CC) and disulfiram (D). The apparent onset of maximal inhibition of hepatic low Km ALDH occurred at 2 h for 50 mg/kg MTT (subcutaneous, s.c.) and 7 mg/kg CC (oral) and at 24 h for 300 mg/kg D (oral). The relative magnitude of maximal inhibition of low Km ALDH was CC greater than D greater than MTT. The relative duration of enzyme inhibition was D greater than MTT greater than CC. High Km ALDH was only inhibited by CC. Hepatic low Km ALDH was selectively inhibited by s.c. and oral administration of 125 mg/kg MTT. For s.c. administration of 125 mg/kg MTT, the magnitude of maximal enzyme inhibition and the duration of inhibition were greater than for the 50 mg/kg dose. Oral administration of 125 mg/kg MTT produced similar inhibition of hepatic low Km ALDH compared with s.c. administration of the same dose. The time course of blood ethanol and acetaldehyde concentrations was determined for the intravenous infusion of two 0.3-g/kg doses of ethanol to rats that were pretreated orally with saline (1 h), MTT (125 mg/kg, 2 h), or CC (7 mg/kg, 1 h). The relative increase in blood acetaldehyde concentration compared with saline pretreatment was CC greater than MTT. The elimination of ethanol from blood was slower in the MTT- and CC-pretreated animals, and this effect was more pronounced for CC pretreatment. Overall, the data demonstrate that the characteristics of hepatic ALDH inhibition for MTT are different from those of the known ALDH inhibitors, CC and D.     

Prophylactic and Therapeutic Potential of Acetyl‐l‐carnitine against Acetaminophen‐Induced Hepatotoxicity in Mice

Prophylactic and therapeutic effects of acetylcarnitine against acetaminophen‐induced hepatotoxicity were studied in mice. To evaluate the prophylactic effects of acetylcarnitine, mice were supplemented with acetylcarnitine (2 mmol/kg/day per oral (p.o.) for 5 days) before a single dose of acetaminophen (350 mg/kg intraperitoneal (i.p.)). Animals were sacrificed 6 h after acetaminophen injection. Acetaminophen significantly increased the markers of liver injury, hepatic reactive oxygen species, and nitrate/nitrite, and decreased hepatic glutathione (GSH) and the antioxidant enzymes. Acetylcarnitine supplementation resulted in reversal of all biochemical parameters toward the control values. To explore the therapeutic effects of acetylcarnitine, mice were given a single dose of acetylcarnitine (0.5, 1, and 2 mmol/kg p.o.) 1.5 h after acetaminophen. Animals were sacrificed 6 h after acetaminophen. Acetylcarnitine administration resulted in partial reversal of liver injury only at 2 mmol/kg p.o. At equimolar doses, N‐acetylcystiene was superior as therapeutic agent to acetylcarnitine. However, acetylcarnitine potentiated the effect of N‐acetylcystiene in the treatment of acetaminophen toxicity.     

Hepcidin and hemojuvelin gene expression in rat liver damage: in vivo and in vitro studies

In this work, we used two rat models, partial hepatectomy (PH) and CCl(4) administration, to study the changes in iron pathways in response to hepatic damage. Liver injury induced changes in the hepatic gene expression of hepcidin, hemojuvelin (Hjv), several other proteins of iron metabolism, and several cytokines such as IL-1beta, IL-6, TNF-alpha, and IFN-gamma. Hepcidin gene expression was upregulated between 4 and 8 h with a maximum up to 16 h after surgery. However, Hjv gene expression was downregulated at the same time. An early upregulation of hepcidin (3 h) and downregulation of Hjv gene expression was found after CCl(4) administration. Transferrin receptor 1 and ferritin H gene expression was upregulated, whereas ferroportin 1 gene expression was downregulated. Hepatic IL-6 gene expression was upregulated early after PH and reached maximum 8 h after the PH. In CCl(4)-induced liver injury, IL-6, IL-1beta, TNF-alpha, and IFN-gamma upregulation were found at the maximum 12 h after the administration of the toxin. Treatment of isolated rat hepatocytes with IL-6 and, to a lesser extent, with IL-1beta but not with TNF-alpha or IFN-gamma dose dependently upregulated hepcidin and downregulated Hjv gene expression. In hepatic damage, changes of the hepatic gene expression of the main proteins involved in iron metabolism may be induced by locally synthesized mediators.     

Interleukin-22 Protects against Acute Alcohol-Induced Hepatotoxicity in Mice

The protective effects of interleukin-22 (IL-22) on acute alcohol-induced liver injury were investigated. Mice were gavaged with 7 doses of alcohol (56% wt/vol, 15.2 mL/kg of body weight for each dose) over the 24 h, and IL-22 (0.5 mg/kg BW) was given to the mice by injection into the tail vein 1 h after alcohol administration. The results indicated that acute alcohol administration caused prominent hepatic microvesicular steatosis and an elevation of serum transaminase activities, induced a significant decrease in hepatic glutathione in conjunction with enhanced lipid peroxidation, and increased hepatocyte apoptosis as well as hepatic TNF-alpha production. IL-22 treatment attenuated these adverse changes induced by acute alcohol administration. The protective effects of IL-22 on alcohol-induced hepatotoxicity were due mainly to its anti-inflammatory, anti-oxidant, and anti-apoptotic features.     

Interleukin-22 protects against acute alcohol-induced hepatotoxicity in mice

The protective effects of interleukin-22 (IL-22) on acute alcohol-induced liver injury were investigated. Mice were gavaged with 7 doses of alcohol (56% wt/vol, 15.2 mL/kg of body weight for each dose) over the 24 h, and IL-22 (0.5 mg/kg BW) was given to the mice by injection into the tail vein 1 h after alcohol administration. The results indicated that acute alcohol administration caused prominent hepatic microvesicular steatosis and an elevation of serum transaminase activities, induced a significant decrease in hepatic glutathione in conjunction with enhanced lipid peroxidation, and increased hepatocyte apoptosis as well as hepatic TNF-alpha production. IL-22 treatment attenuated these adverse changes induced by acute alcohol administration. The protective effects of IL-22 on alcohol-induced hepatotoxicity were due mainly to its anti-inflammatory, anti-oxidant, and anti-apoptotic features.     

Hepatoprotective effect of allicin against acetaminophen‐induced liver injury: Role of inflammasome pathway,apoptosis, and liver regeneration

Acetaminophen (APAP) overdose leads to liver injury. NLRP3 inflammasome is a key player in APAP‐induced inflammation. Also, apoptosis and liver regeneration play an important role in liver injury. Therefore, we assessed allicin's protective effect on APAP‐induced hepatotoxicity and studied its effect on NLRP3 inflammasome and apoptosis. Mice in the APAP group were injected by APAP (250 mg/kg, intraperitoneal). The allicin‐treated group received allicin orally (10 mg/kg/d) during 7 days before APAP injection. Serum and hepatic tissues were separated 24 hours after APAP injection. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), albumin, alkaline phosphatase (ALP), and hepatic malondialdehyde (MDA) were assessed using the colorimetric method. Hepatic NLRP3 inflammasome, caspase‐1, and interleukin‐1β (IL‐1β) were estimated using enzyme‐linked immunosorbent assay. Hepatic Bcl‐2 and Ki‐67 were investigated by immunohistochemistry. APAP significantly increased AST, ALT, and ALP, whereas allicin significantly decreased their levels. Also, APAP significantly decreased albumin and allicin significantly improved it. APAP produced changes in liver morphology, including inflammation and massive coagulative necrosis. Allicin protected the liver from APAP‐induced necrosis, apoptosis, and hepatocellular degeneration via increasing Bcl‐2 and Ki‐67 levels. APAP significantly increased the hepatic MDA, whereas allicin significantly prevented this increase. APAP markedly activated the NLRP3 inflammasome pathway and consequently increased the production of caspase‐1 and IL‐1β. Interestingly, we found that allicin significantly inhibited NLRP3 inflammasome activation, which resulted in decreased caspase‐1 and IL‐1β levels. Allicin has a hepatoprotective effect against APAP‐induced liver injury via the decline of oxidative stress and inhibition of the inflammasome pathway and apoptosis. Therefore, allicin might be a novel tool to halt the progression of APAP‐stimulated hepatotoxicity.     

Mechanism of salutary effects of astringinin on rodent hepatic injury following trauma-hemorrhage: Akt-dependent hemeoxygenase-1 signaling pathways

Astringinin can attenuate organ injury following trauma-hemorrhage, the mechanism remains unknown. Protein kinase B/hemeoxygenase-1 (Akt/HO-1) pathway exerts potent anti-inflammatory effects in various tissues. The aim of this study is to elucidate whether Akt/HO-1 plays any role in astringinin-mediated attenuation of hepatic injury following trauma-hemorrhage. For study this, male Sprague-Dawley rats underwent trauma-hemorrhage (mean blood pressure 35-40 mmHg for 90 min) followed by fluid resuscitation. A single dose of astringinin (0.3 mg/kg body weight) with or without a PI3K inhibitor (wortmannin) or a HO antagonist (chromium-mesoporphyrin) was administered during resuscitation. Various parameters were measured at 24 h post-resuscitation. Results showed that trauma-hemorrhage increased plasma aspartate and alanine aminotransferases (AST and ALT) concentrations and hepatic myeloperoxidase activity, cytokine induced neutrophil chemoattractant (CINC)-1, CINC-3, intercellular adhesion molecule-1, and interleukin-6 levels. These parameters were significantly improved in the astringinin-treated rats subjected to trauma-hemorrhage. Astringinin treatment also increased hepatic Akt activation and HO-1 expression as compared with vehicle-treated trauma-hemorrhaged rats. Co-administration of wortmannin or chromium-mesoporphyrin abolished the astringinin-induced beneficial effects on post-resuscitation pro-inflammatory responses and hepatic injury. These findings collectively suggest that the salutary effects of astringinin administration on attenuation of hepatic injury after trauma-hemorrhage are likely mediated via Akt dependent HO-1 up-regulation.     

The role of estrogen receptor subtypes on hepatic neutrophil accumulation following trauma-hemorrhage: direct modulation of CINC-1 production by Kupffer cells

Although 17beta-estradiol (E2) administration following trauma-hemorrhage (T-H) reduces liver injury by decreasing neutrophil accumulation via estrogen receptor (ER)-alpha, it remains unclear whether cytokine-induced neutrophil chemoattractant (CINC)-1 production by Kupffer cells (KC) is directly modulated by ER-alpha under such condition. Male rats underwent laparotomy and hemorrhagic shock (40 mmHg for 90 min), followed by resuscitation with four times the shed blood volume in the form of Ringer's lactate. ER-alpha agonist propyl pyrazole triol (PPT; 5 microg/kg), ER-beta agonist diarylpropionitrile (DPN; 5 microg/kg), E2 (50 microg/kg), or vehicle (10% DMSO) was administered subcutaneously during resuscitation; rats were sacrificed 24h thereafter. KC were isolated and cultured with ER agonists to examine if they directly affect CINC-1 production. T-H increased plasma alanine aminotransferase (ALT; hepatic injury) and hepatic myeloperoxidase (MPO) activity. E2, PPT and DPN administration reduced increased ALT; however, PPT was more effective than DPN. PPT and E2, but not DPN significantly attenuated increased hepatic MPO activity and CINC-1 levels. PPT addition in vitro (10(-7) and 10(-6)M) significantly reduced KC CINC-1 production. In summary, the salutary effects of E2 against hepatic injury are mediated predominantly via ER-alpha which directly modulates KC CINC-1 production and hepatic neutrophil accumulation following T-H.     

Mechanism of salutary effects of androstenediol on hepatic function after trauma-hemorrhage: role of endothelial and inducible nitric oxide synthase

Recent studies have shown that administration of dehydroepiandrosterone (DHEA) after trauma-hemorrhage (T-H) improves cardiovascular and hepatic function in male animals. Although androstenediol, one of the DHEA metabolites, has been recently reported to produce salutary effects on cardiac function and splanchnic perfusion after T-H, it remains unknown whether androstenediol per se has any salutary effects on hepatic function under those conditions. To study this, male Sprague-Dawley rats underwent laparotomy and approximately 90 min of hemorrhagic shock (35-40 mmHg), followed by resuscitation with four times the shed blood volume in the form of Ringer lactate. Androstenediol (1 mg/kg body wt iv) was administered at the end of resuscitation, and the animals were killed 24 h later. T-H significantly reduced portal blood flow, bile production, and serum albumin levels. Portal pressure, serum alanine aminotransferase, hepatic nitrate/nitrite, inducible nitric oxide synthase (iNOS), and endothelin-1 markedly increased after T-H. The alterations in these parameters induced by T-H were significantly attenuated in rats treated with androstenediol. Endothelial NOS (eNOS) expression, which was not different between T-H and sham, was found to be significantly elevated in T-H androstenediol-treated rats. These data suggest that improvement in hepatic perfusion by androstenediol after T-H is likely due to a decrease in endothelin-1 and induction of eNOS. Moreover, the decrease in hepatic damage after androstenediol administration is likely related to liver iNOS downregulation. Thus androstenediol appears to be a novel and useful adjunct for restoring hepatic function in male animals after adverse circulatory conditions.