Alcoholic liver disease: from pathophysiology to therapy

Pioglitazone reverses alcohol-induced alterations in alveolar macrophage mitochondrial phenotype

BACKGROUND

People with alcohol use disorder (AUD) have an increased risk of developing pneumonia and pulmonary diseases. Alveolar macrophages (AMs) are immune cells of the lower respiratory tract that are necessary for clearance of pathogens. However, alcohol causes AM oxidative stress, mitochondrial damage and dysfunction, and diminished phagocytic capacity, leading to lung injury and immune suppression.

METHODS

AMs were isolated by bronchoalveolar lavage from people with AUD and male and female C57BL/6J mice given chronic ethanol (20% w/v, 12 weeks) in drinking water. The peroxisome proliferator-activated receptor γ ligand, pioglitazone, was used to treat human AMs ex vivo (10 μM, 24 h) and mice in vivo by oral gavage (10 mg/kg/day). Levels of AM mitochondrial superoxide and hypoxia-inducible factor-1 alpha (HIF-1α) mRNA, a marker of oxidative stress, were measured by fluorescence microscopy and RT-qPCR, respectively. Mouse AM phagocytic ability was determined by internalized Staphylococcus aureus, and mitochondrial capacity, dependency, and flexibility for glucose, long-chain fatty acid, and glutamine oxidation were measured using an extracellular flux analyzer. In vitro studies used a murine AM cell line, MH-S (±0.08% ethanol, 72 h) to investigate mitochondrial fuel oxidation and ATP-linked respiration.

RESULTS

Pioglitazone treatment decreased mitochondrial superoxide in AMs from people with AUD and ethanol-fed mice and HIF-1α mRNA in ethanol-fed mouse lungs. Pioglitazone also reversed mouse AM glutamine oxidation and glucose or long-chain fatty acid flexibility to meet basal oxidation needs. In vitro, ethanol decreased the rate of AM mitochondrial and total ATP production, and pioglitazone improved changes in glucose and glutamine oxidation.

CONCLUSIONS

Pioglitazone reversed chronic alcohol-induced oxidative stress in human AM and mitochondrial substrate oxidation flexibility and superoxide levels in mouse AM. Decreased ethanol-induced AM HIF-1α mRNA with pioglitazone suggests that this pathway may be a focus for metabolic-targeted therapeutics to improve morbidity and mortality in people with AUD.

Changes in Lipidomics, Metabolomics, and the Gut Microbiota in CDAA-Induced NAFLD Mice after Polyene Phosphatidylcholine Treatment

Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in most parts of the world. Although there is no first-line drug approved for the treatment of NAFLD, polyene phosphatidylcholine (PPC) is used by clinicians to treat NAFLD patients. This study aimed to evaluate the efficacy of PPC on a mice model of NAFLD, and to study the PPC's mechanism of action. The mice were fed a choline-deficient, L-amino acid-defined (CDAA) diet to induce NAFLD and were subsequently treated with PPC. The treatment effects were evaluated by the liver index, histopathological examination, and routine blood chemistry analyses. Lipidomics and metabolomics analyses of 54 samples were carried out using ultraperformance liquid chromatography (UPLC) coupled to a mass spectrometer to select for changes in metabolites associated with CDAA diet-induced NAFLD and the effects of PPC treatment. The intestinal flora of mice were extracted for gene sequencing to find differences before and after the induction of NAFLD and PPC treatment. PPC significantly improved the CDAA diet-induced NAFLD condition in mice. A total of 19 metabolites including 5 polar metabolites and 14 lipids showed marked changes. In addition, significant differences in the abundance of Lactobacillus were associated with NAFLD. We inferred that the protective therapeutic effect of PPC on the liver was related to the supplement of phosphatidylcholine, lysophosphatidylcholine, and sphingomyelin (PC, LPC, and SM, resectively) and acylcarnitine metabolism. This study developed a methodology for exploring the pathogenesis of NAFLD and can be extended to other therapeutic agents for treating NAFLD.

Proteomic analysis of alcohol-associated hepatitis reveals glycoprotein NMB (GPNMB) as a novel hepatic and serum biomarker

Alcohol consumption remains a leading cause of liver disease worldwide, resulting in a complex array of hepatic pathologies, including steatosis, steatohepatitis, and cirrhosis. Individuals who progress to a rarer form of alcohol-associated liver disease (ALD), alcohol-associated hepatitis (AH), require immediate life-saving intervention in the form of liver transplantation. Rapid onset of AH is poorly understood and the metabolic mechanisms contributing to the progression to liver failure remain undetermined. While multiple mechanisms have been identified that contribute to ALD, no cures exist and mortality from AH remains high. To identify novel pathways associated with AH, our group utilized proteomics to investigate AH-specific biomarkers in liver explant tissues. The goal of the present study was to determine changes in the proteome as well as epigenetic changes occurring in AH. Protein abundance and acetylomic analyses were performed utilizing nHPLC-MS/MS, revealing significant changes to proteins associated with metabolic and inflammatory fibrosis pathways. Here, we describe a novel hepatic and serum biomarker of AH, glycoprotein NMB (GPNMB). The anti-inflammatory protein GPNMB was significantly increased in AH explant liver and serum compared to healthy donors by 50-fold and 6.5-fold, respectively. Further, bioinformatics analyses identified an AH-dependent decrease in protein abundance across fatty acid degradation, biosynthesis of amino acids, and carbon metabolism. The greatest increases in protein abundance were observed in pathways for focal adhesion, lysosome, phagosome, and actin cytoskeleton. In contrast with the hyperacetylation observed in murine models of ALD, protein acetylation was decreased in AH compared to normal liver across fatty acid degradation, biosynthesis of amino acids, and carbon metabolism. Interestingly, immunoblot analysis found epigenetic marks were significantly increased in AH explants, including Histone H3K9 and H2BK5 acetylation. The increased acetylation of histones likely plays a role in the altered proteomic profile observed, including increases in GPNMB. Indeed, our results reveal that the AH proteome is dramatically impacted through unanticipated and unknown mechanisms. Understanding the origin and consequences of these changes will yield new mechanistic insight for ALD as well as identify novel hepatic and serum biomarkers, such as GPNMB.

Alcoholic-Hepatitis, Links to Brain and Microbiome: Mechanisms, Clinical and Experimental Research

The following review article presents clinical and experimental features of alcohol-induced liver disease (ALD). Basic aspects of alcohol metabolism leading to the development of liver hepatotoxicity are discussed. ALD includes fatty liver, acute alcoholic hepatitis with or without liver failure, alcoholic steatohepatitis (ASH) leading to fibrosis and cirrhosis, and hepatocellular cancer (HCC). ALD is fully attributable to alcohol consumption. However, only 10-20% of heavy drinkers (persons consuming more than 40 g of ethanol/day) develop clinical ALD. Moreover, there is a link between behaviour and environmental factors that determine the amount of alcohol misuse and their liver disease. The range of clinical presentation varies from reversible alcoholic hepatic steatosis to cirrhosis, hepatic failure, and hepatocellular carcinoma. We aimed to (1) describe the clinico-pathology of ALD, (2) examine the role of immune responses in the development of alcoholic hepatitis (ASH), (3) propose diagnostic markers of ASH, (4) analyze the experimental models of ALD, (5) study the role of alcohol in changing the microbiota, and (6) articulate how findings in the liver and/or intestine influence the brain (and/or vice versa) on ASH; (7) identify pathways in alcohol-induced organ damage and (8) to target new innovative experimental concepts modeling the experimental approaches. The present review includes evidence recognizing the key toxic role of alcohol in ALD severity. Cytochrome p450 CYP2E1 activation may change the severity of ASH. The microbiota is a key element in immune responses, being an inducer of proinflammatory T helper 17 cells and regulatory T cells in the intestine. Alcohol consumption changes the intestinal microbiota and influences liver steatosis and liver inflammation. Knowing how to exploit the microbiome to modulate the immune system might lead to a new form of personalized medicine in ALF and ASH.

Chronic ethanol consumption induces mitochondrial protein acetylation and oxidative stress in the kidney

In this study, we present the novel findings that chronic ethanol consumption induces mitochondrial protein hyperacetylation in the kidney and correlates with significantly increased renal oxidative stress. A major proteomic footprint of alcoholic liver disease (ALD) is an increase in hepatic mitochondrial protein acetylation. Protein hyperacetylation has been shown to alter enzymatic function of numerous proteins and plays a role in regulating metabolic processes. Renal mitochondrial targets of hyperacetylation include numerous metabolic and antioxidant pathways, such as lipid metabolism, oxidative phosphorylation, and amino acid metabolism, as well as glutathione and thioredoxin pathways. Disruption of protein lysine acetylation has the potential to impair renal function through metabolic dysregulation and decreased antioxidant capacity. Due to a significant elevation in ethanol-mediated renal oxidative stress, we highlight the acetylation of superoxide dismutase, peroxiredoxins, glutathione reductase, and glutathione transferase enzymes. Since oxidative stress is a known factor in ethanol-induced nephrotoxicity, we examined biochemical markers of protein hyperacetylation and oxidative stress. Our results demonstrate increased protein acetylation concurrent with depleted glutathione, altered Cys redox potential, and the presence of 4-HNE protein modifications in our 6-week model of early-stage alcoholic nephrotoxicity. These findings support the hypothesis that ethanol metabolism causes an influx of mitochondrial metabolic substrate, resulting in mitochondrial protein hyperacetylation with the potential to impact mitochondrial metabolic and antioxidant processes.

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Chronic ethanol metabolism induces mitochondrial protein hyperacetylation in the kidney.

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Ethanol-induced hyperacetylation occurs on metabolic and antioxidant proteins.

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The onset of renal oxidative stress correlates with mitochondrial protein hyperacetylation.

An evidence-based update on the pharmacological activities and possible molecular targets of Lycium barbarum polysaccharides

Lycium barbarum berries, also named wolfberry, Fructus lycii, and Goji berries, have been used in the People’s Republic of China and other Asian countries for more than 2,000 years as a traditional medicinal herb and food supplement. L. barbarum polysaccharides (LBPs) are the primary active components of L. barbarum berries and have been reported to possess a wide array of pharmacological activities. Herein, we update our knowledge on the main pharmacological activities and possible molecular targets of LBPs. Several clinical studies in healthy subjects show that consumption of wolfberry juice improves general wellbeing and immune functions. LBPs are reported to have antioxidative and antiaging properties in different models. LBPs show antitumor activities against various types of cancer cells and inhibit tumor growth in nude mice through induction of apoptosis and cell cycle arrest. LBPs may potentiate the efficacy of lymphokine activated killer/interleukin-2 combination therapy in cancer patients. LBPs exhibit significant hypoglycemic effects and insulin-sensitizing activity by increasing glucose metabolism and insulin secretion and promoting pancreatic β-cell proliferation. They protect retinal ganglion cells in experimental models of glaucoma. LBPs protect the liver from injuries due to exposure to toxic chemicals or other insults. They also show potent immunoenhancing activities in vitro and in vivo. Furthermore, LBPs protect against neuronal injury and loss induced by β-amyloid peptide, glutamate excitotoxicity, ischemic/reperfusion, and other neurotoxic insults. LBPs ameliorate the symptoms of mice with Alzheimer’s disease and enhance neurogenesis in the hippocampus and subventricular zone, improving learning and memory abilities. They reduce irradiation- or chemotherapy-induced organ toxicities. LBPs are beneficial to male reproduction by increasing the quality, quantity, and motility of sperm, improving sexual performance, and protecting the testis against toxic insults. Moreover, LBPs exhibit hypolipidemic, cardioprotective, antiviral, and antiinflammatory activities. There is increasing evidence from preclinical and clinical studies supporting the therapeutic and health-promoting effects of LBPs, but further mechanistic and clinical studies are warranted to establish the dose–response relationships and safety profiles of LBPs.

β-Lapachone alleviates alcoholic fatty liver disease in rats

Alcohol-induced liver injury is the most common liver disease in which fatty acid metabolism is altered. It is thought that altered NAD(+)/NADH redox potential by alcohol in the liver causes fatty liver by inhibiting fatty acid oxidation and the activity of tricarboxylic acid cycle reactions. β-Lapachone (βL), a naturally occurring quinone, has been shown to stimulate fatty acid oxidation in an obese mouse model by activating adenosine monophosphate-activated protein kinase (AMPK). In this report, we clearly show that βL reduced alcohol-induced hepatic steatosis and induced fatty acid oxidizing capacity in ethanol-fed rats. βL treatment markedly decreased hepatic lipids while serum levels of lipids and lipoproteins were increased in rats fed ethanol-containing liquid diets with βL administration. Furthermore, inhibition of lipolysis, enhancement of lipid mobilization to mitochondria and upregulation of mitochondrial β-oxidation activity in the soleus muscle were observed in ethanol/βL-treated animals compared to the ethanol-fed rats. In addition, the activity of alcohol dehydrogenase, but not aldehyde dehydrogenase, was significantly increased in rats fed βL diets. βL-mediated modulation of NAD(+)/NADH ratio led to the activation of AMPK signaling in these animals.

CONCLUSION

Our results suggest that improvement of fatty liver by βL administration is mediated by the upregulation of apoB100 synthesis and lipid mobilization from the liver as well as the direct involvement of βL on NAD(+)/NADH ratio changes, resulting in the activation of AMPK signaling and PPARα-mediated β-oxidation. Therefore, βL-mediated alteration of NAD(+)/NADH redox potential may be of potential therapeutic benefit in the clinical setting.

Increased nitroxidative stress promotes mitochondrial dysfunction in alcoholic and nonalcoholic fatty liver disease

Increased nitroxidative stress causes mitochondrial dysfunctions through oxidative modifications of mitochondrial DNA, lipids, and proteins. Persistent mitochondrial dysfunction sensitizes the target cells/organs to other pathological risk factors and thus ultimately contributes to the development of more severe disease states in alcoholic and nonalcoholic fatty liver disease. The incidences of nonalcoholic fatty liver disease continuously increase due to high prevalence of metabolic syndrome including hyperlipidemia, hypercholesterolemia, obesity, insulin resistance, and diabetes. Many mitochondrial proteins including the enzymes involved in fat oxidation and energy supply could be oxidatively modified (including S-nitrosylation/nitration) under increased nitroxidative stress and thus inactivated, leading to increased fat accumulation and ATP depletion. To demonstrate the underlying mechanism(s) of mitochondrial dysfunction, we employed a redox proteomics approach using biotin-N-maleimide (biotin-NM) as a sensitive biotin-switch probe to identify oxidized Cys residues of mitochondrial proteins in the experimental models of alcoholic and acute liver disease. The aims of this paper are to briefly describe the mechanisms, functional consequences, and detection methods of mitochondrial dysfunction. We also describe advantages and limitations of the Cys-targeted redox proteomics method with alternative approaches. Finally, we discuss various applications of this method in studying oxidatively modified mitochondrial proteins in extrahepatic tissues or different subcellular organelles and translational research.

Characterization of 4-HNE modified L-FABP reveals alterations in structural and functional dynamics

4-Hydroxynonenal (4-HNE) is a reactive α,β-unsaturated aldehyde produced during oxidative stress and subsequent lipid peroxidation of polyunsaturated fatty acids. The reactivity of 4-HNE towards DNA and nucleophilic amino acids has been well established. In this report, using proteomic approaches, liver fatty acid-binding protein (L-FABP) is identified as a target for modification by 4-HNE. This lipid binding protein mediates the uptake and trafficking of hydrophobic ligands throughout cellular compartments. Ethanol caused a significant decrease in L-FABP protein (P<0.001) and mRNA (P<0.05), as well as increased poly-ubiquitinated L-FABP (P<0.001). Sites of 4-HNE adduction on mouse recombinant L-FABP were mapped using MALDI-TOF/TOF mass spectrometry on apo (Lys57 and Cys69) and holo (Lys6, Lys31, His43, Lys46, Lys57 and Cys69) L-FABP. The impact of 4-HNE adduction was found to occur in a concentration-dependent manner; affinity for the fluorescent ligand, anilinonaphthalene-8-sulfonic acid, was reduced from 0.347 µM to Kd(1) = 0.395 µM and Kd(2) = 34.20 µM. Saturation analyses revealed that capacity for ligand is reduced by approximately 50% when adducted by 4-HNE. Thermal stability curves of apo L-FABP was also found to be significantly affected by 4-HNE adduction (ΔTm = 5.44°C, P<0.01). Computational-based molecular modeling simulations of adducted protein revealed minor conformational changes in global protein structure of apo and holo L-FABP while more apparent differences were observed within the internal binding pocket, revealing reduced area and structural integrity. New solvent accessible portals on the periphery of the protein were observed following 4-HNE modification in both the apo and holo state, suggesting an adaptive response to carbonylation. The results from this study detail the dynamic process associated with L-FABP modification by 4-HNE and provide insight as to how alterations in structural integrity and ligand binding may a contributing factor in the pathogenesis of ALD.

Protein carbonylation in a murine model for early alcoholic liver disease

Hepatic oxidative stress and subsequent lipid peroxidation are well-recognized consequences of sustained ethanol consumption. The covalent adduction of nucleophilic amino acid side-chains by lipid electrophiles is significantly increased in patients with alcoholic liver disease (ALD); a global assessment of in vivo protein targets and the consequences of these modifications, however, has not been conducted. In this article, we describe the identification of novel protein targets for covalent adduction in a 6-week murine model for ALD. Ethanol-fed mice displayed a 2-fold increase in hepatic TBARS, while immunohistochemical analysis for the reactive aldehydes 4-hydroxynonenal (4-HNE), 4-oxononenal (4-ONE), acrolein (ACR), and malondialdehyde (MDA) revealed a marked increase in the staining of modified proteins in the ethanol-treated mice. Increased protein carbonyl content was confirmed utilizing subcellular fractionation of liver homogenates followed by biotin-tagging through hydrazide chemistry, where approximately a 2-fold increase in modified proteins was observed in microsomal and cytosolic fractions. To determine targets of protein carbonylation, a secondary hydrazide method coupled to a highly sensitive 2-dimensional liquid chromatography tandem mass spectrometry (2D LC-MS/MS or MuDPIT) technique was utilized. Our results have identified 414 protein targets for modification by reactive aldehydes in ALD. The presence of novel in vivo sites of protein modification by 4-HNE (2), 4-ONE (4) and ACR (2) was also confirmed in our data set. While the precise impact of protein carbonylation in ALD remains unknown, a bioinformatic analysis of the data set has revealed key pathways associated with disease progression, including fatty acid metabolism, drug metabolism, oxidative phosphorylation, and the TCA cycle. These data suggest a major role for aldehyde adduction in the pathogenesis of ALD.

The effect of Lycium barbarum polysaccharide on alcohol-induced oxidative stress in rats

The aim of this study was to investigate the effects of Lycium barbarum Polysaccharide (LBP) on alcohol-induced liver damage in rats. A total of 36 rats were divided into control, ethanol and ethanol + LBP groups. Rats in the ethanol group were fed 7 g ethanol/kg body weight by gastric infusion, three times a day, for 30 consecutive days, while rats in the control group received the same volume of physiological saline instead of ethanol, and rats in ethanol + LBP group were fed both ethanol (7 g/kg body weight) and LBP (300 mg/Kg body weight/day). Alcoholic liver injury was examined by serum ALT and AST activities, alcoholic fatty liver was assessed by lipid levels, and oxidative stress was evaluated by SOD, CAT, GSH-Px, GSH and MDA assays. In the ethanol group, a significant elevation of enzymes and lipid in serum, increased MDA level and depletion of SOD, CAT, GSH-Px and GSH in liver were observed. LBP administration significantly ameliorated liver injury, prevented the progression of alcohol-induced fatty liver, and improved the antioxidant functions when compared with the ethanol group. Histopathological examination of rat liver revealed that LBP administration protected liver cells from the damage induced by ethanol. The results suggest that LBP is a promising agent to protect the liver from hepatotoxicity and fatty liver induced by ethanol intake.

Profiling impaired hepatic endoplasmic reticulum glycosylation as a consequence of ethanol ingestion

Alcoholic liver disease (ALD) is a prominent cause of morbidity and mortality in the United States. Alterations in protein folding occur in numerous disease states, including ALD. The endoplasmic reticulum (ER) is the primary site of post-translational modifications (PTM) within the cell. Glycosylation, the most abundant PTM, affects protein stability, structure, localization, and activity. Decreases in hepatic glycosylation machinery have been observed in rodent models of ALD, but specific protein targets have not been identified. Utilizing two-dimensional gel electrophoresis and liquid chromatography-tandem mass spectrometry, glycoproteins were identified in hepatic microsomal fractions from control and ethanol-fed mice. This study reports for the first time a global decrease in ER glycosylation. Additionally, the identification of 30 glycoproteins within this fraction elucidates pathway-specific alterations in ALD impaired glycosylation. Among the identified proteins, triacylglycerol hydrolase (TGH) is positively affected by glycosylation, showing increased activity following the addition of sugar moieties. Impaired TGH activity is associated with increased cellular storage of lipids and provides a potential mechanism for the observed pathologies associated with ALD.

Polyenephosphatidylcholine prevents alcoholic liver disease in PPARalpha-null mice through attenuation of increases in oxidative stress

BACKGROUND/AIMS

Alcoholic liver disease (ALD) is one of the leading causes of cirrhosis and yet efficient therapeutic strategies are lacking. Polyenephosphatidylcholine (PPC), a major component of essential phospholipids, prevented alcoholic liver fibrosis in baboons, but its precise mechanism remains uncertain. We aimed to explore the effects of PPC on ALD using ethanol-fed peroxisome proliferator-activated receptor alpha (Ppara)-null mice, showing several similarities to human ALD.

METHODS

Male wild-type and Ppara-null mice were pair-fed a Lieber-DeCarli control or 4% ethanol-containing diet with or without PPC (30 mg/kg/day) for 6 months.

RESULTS

PPC significantly ameliorated ethanol-induced hepatocyte damage and hepatitis in Ppara-null mice. These effects were likely a consequence of decreased oxidative stress through down-regulation of reactive oxygen species (ROS)-generating enzymes, including cytochrome P450 2E1, acyl-CoA oxidase, and NADPH oxidases, in addition to restoration of increases in Toll-like receptor 4 and CD14. PPC also decreased Bax and truncated Bid, thus inhibiting apoptosis. Furthermore, PPC suppressed increases in transforming growth factor-beta1 expression and hepatic stellate cell activation, which retarded hepatic fibrogenesis.

CONCLUSIONS

PPC exhibited anti-inflammatory, anti-apoptotic, and anti-fibrotic effects on ALD as a result of inhibition of the overexpression of ROS-generating enzymes. Our results demonstrate detailed molecular mechanisms of the anti-oxidant action of PPC.

Overexpression of aldehyde dehydrogenase-2 attenuates chronic alcohol exposure-induced apoptosis, change in Akt and Pim signalling in liver

1. The liver, the main site of ethanol oxidation, is extremely vulnerable to the toxic effects of alcohol. Chronic alcohol intake has been shown to result in alcoholic liver disease, although the precise mechanism of action remains poorly understood. 2. The present study was designed to examine the impact of facilitated acetaldehyde metabolism via overexpression of aldehyde dehydrogenase-2 (ALDH2) on chronic alcohol ingestion-induced hepatic damage. Mice (wild-type Friend Virus B (FVB) and ALDH2 transgenic mice) were placed on a 4% alcohol or control diet for 12 weeks. Pro- and anti-apoptotic proteins, including p53, Omi/HtrA2, Bcl-2, Bax, X-linked inhibitor of apoptosis protein (XIAP), Akt, phosphorylated (p) Akt, the Akt downstream signalling molecule Pim and pPim, were examined using immunoblot analysis. Apoptosis and protein damage were assessed using the caspase 3 assay and protein carbonyl formation, respectively. 3. The data revealed that alcohol intake enhanced expression of p53, Omi/HtrA2, Bcl-2 and Bax without affecting XIAP expression or the Bcl-2/Bax ratio. Total Akt and pPim were downregulated in response to alcohol, whereas total Pim was upregulated in conjunction with unchanged pAkt. As a result, the pAkt : Akt and pPim : Pim ratios were elevated and reduced, respectively, in response to alcohol. All these effects that resulted from alcohol exposure were attenuated or ablated by ALDH2. 4. Collectively, the results suggest that ALDH2 may effectively ameliorate alcohol-induced hepatic apoptosis and changes in Akt as well as Pim signalling.

The protective effects of Phyllanthus emblica Linn. extract on ethanol induced rat hepatic injury

This study was undertaken to investigate the protective effects of Phyllanthus emblica Linn. (PE) extract on ethanol induced rat hepatic injury. PE (0.5 and 1 mg/ml) increased cell viability of rat primary cultured hepatocytes being treated with ethanol (96 microl/m) by increasing % MTT and decreasing the release of transaminase. Hepatotoxic markers studied in rats included serum transaminases (AST and ALT), serum triglyceride (STG), hepatic triglyceride (HTG), TNF-alpha and IL-1beta together with histopathological examination. Pretreatment of rats with PE at oral dose of 25, 50 and 75 mg/kg or SL (silymarin, a reference hepatoprotective agent) at 5 mg/kg, 4 h before ethanol, lowered the ethanol induced levels of AST, ALT and IL-1beta. The 75 mg/kg PE dose gave the best result similar to SL. Treatment of rats with PE (75 mg/kg/day) or SL (5 mg/kg/day) for 7 days after 21 days with ethanol (4 g/kg/day, p.o.) enhanced liver cell recovery by bringing the levels of AST, ALT, IL-1beta back to normal. Histopathological studies confirmed the beneficial roles of PE and SL against ethanol induced liver injury in rats.