Model Of Alcoholic Fatty Liver Disease Research Articles

Alleviation of Alcoholic Fatty Liver by Dendrobium officinale Flower Extracts due to Regulation of Gut Microbiota and Short-Chain Fatty Acids in Mice Exposed to Chronic Alcohol.

Alcoholic fatty liver disease (AFLD) is caused by long-term heavy alcohol consumption; therefore, useful and practical methods for the prevention of AFLD are urgently needed. The edible flower of Dendrobium officinale contains diverse flavonoids, and has shown antioxidant activity as well as antihypertensive and anti-inflammatory effects. In this study, an AFLD model was established, the protective effect of D. officinale flower (DOF) ethanol extract on AFLD was evaluated, and its mechanisms were investigated by analyzing gut microbiota and short-chain fatty acids (SCFAs). DOF extract (DOFE) supplementation promoted alcohol metabolism, restored hepatic antioxidant capacity, alleviated oxidative stress, reduced inflammatory factor levels, and inhibited dyslipidemia induced by alcohol intake in chronic alcohol-exposed mice, especially in the high DOFE group. Moreover, DOFE supplementation increased the diversity, structure, and composition of the gut microbiota in mice, restored some of the abnormal SCFA levels caused by AFLD, and helped restore intestinal function. DOFE supplementation significantly increased the relative abundance of Akkermansia, suggesting that Akkermansia may be a potential target of the protective effect of DOFE. Therefore, DOFE supplementation to improve the composition of the gut microbiota may be an effective therapeutic strategy for the prevention of AFLD.

Seabuckthorn polysaccharide combined with astragalus polysaccharide ameliorate alcoholic fatty liver by regulating intestinal flora.

BackgroundAt present, the incidence of alcoholic fatty liver disease (AFLD) is increasing year by year, and numerous studies have confirmed that liver diseases are closely related to intestinal flora. Seabuckthorn and Astragalus membranaceus, as traditional Chinese medicine (TCM) with the homology of medicine and food, have good liver protection, and their polysaccharides can regulate the intestinal flora. Here, we studied the effects of HRP, APS and the combination of the two polysaccharides on the intestinal flora of AFLD mice, which provided scientific basis for the treatment of AFLD with the two polysaccharides.Materials and methodsThirty Kunming (KM) mice were randomly divided into the control group (Con), the model group (Mod), the HRP treatment group (HRP), the APS treatment group (APS), and HRP+APS treatment group (HRP+APS), with six mice in each group. The AFLD model was constructed by continuous intragastric administration of 42% vol Niulanshan ethanol solution for 28 days, and the mice in each polysaccharide group were given corresponding drugs. The levels of AST, ALT, TC and TG in serum of mice were measured. 16S rRNA amplicon sequencing technique was used to determine the diversity and richness of intestinal flora, and the relative abundance of intestinal flora at phylum level and genus level of the mice in each group.ResultsHRP, APS and HRP+APS could reduce the serum levels of AST, ALT, TC and TG in mice. In addition, HRP, APS and HRP + APS restored the diversity, relative abundance and community structure of intestinal mucosa bacteria in AFLD mice to a certain extent. Specifically, HRP, APS and HRP+APS remarkably decreased the ratio of Firmicutes to Bacteroidetes, and ultimately increased the abundance of beneficial bacteria and reduced the abundance of pathogenic bacteria.ConclusionHRP, APS, and HRP+APS can improve the intestinal microecology of AFLD model mice, alleviate liver injury, and maintain normal intestinal function in different degrees.

Caveolin-1 Alleviates Acetaminophen-Induced Hepatotoxicity in Alcoholic Fatty Liver Disease by Regulating the Ang II/EGFR/ERK Axis.

Acetaminophen (APAP) is a widely used antipyretic analgesic which can lead to acute liver failure after overdoses. Chronic alcoholic fatty liver disease (AFLD) appears to enhance the risk and severity of APAP-induced liver injury, and the level of angiotensin II (Ang II) increased sharply at the same time. However, the underlying mechanisms remain unclear. Caveolin-1 (CAV1) has been proven to have a protective effect on AFLD. This study aimed to examine whether CAV1 can protect the APAP-induced hepatotoxicity of AFLD by affecting Ang II or its related targets. In vivo, the AFLD model was established according to the chronic-plus-binge ethanol model. Liver injury and hepatic lipid accumulation level were determined. The levels of Angiotensin converting enzyme 2 (ACE2), Ang II, CAV1, and other relevant proteins were evaluated by western blotting. In vitro, L02 cells were treated with alcohol and oleic acid mixture and APAP. CAV1 and ACE2 expression was downregulated in APAP-treated AFLD mice compared to APAP-treated mice. The overexpression of CAV1 in mice and L02 cells alleviated APAP-induced hepatotoxicity in AFLD and downregulated Ang II, p-EGFR/EGFR and P-ERK/ERK expression. Immunofluorescence experiments revealed interactions between CAV1, Ang II, and EGFR. The application of losartan (an Ang II receptor antagonist) and PD98059 (an ERK1/2 inhibitor) alleviated APAP-induced hepatotoxicity in AFLD. In conclusion, our findings verified that CAV1 alleviates APAP-aggravated hepatotoxicity in AFLD by downregulating the Ang II /EGFR/ERK axis, which could be a novel therapeutic target for its prevention or treatment.

Effects of different swimming exercises on alcoholic fatty liver formation in mice

Objective: To investigate the effects of 7-week swimming exercise with different loads on the improvement of liver lipid metabolism in mice with alcoholic fatty liver disease (AFLD) and its relationship with the regulation of miR-34a/PPARα. Methods: Fifty male KM mice were randomly divided into control group (K, n=10) and alcoholic fatty liver group (AFLD, n=40). The AFLD model was constructed after feeding with 50% alcohol for 7 weeks with 1 d rest per week. After successful model construction, the mice were divided into a model group (M), a 30-min swimming exercise group (LE), a 60-min swimming exercise group (ME), and a 90-min loaded swimming exercise group (HE, 5% of body mass as tail lead load), with 10 mice in each group, for a total of 7 weeks of intervention. After completion, the serum and liver tissues were collected, the liver index, visceral fat ratio, hepatocyte injury indicators, alanine aminotransferase (ALT), aspartate aminotransferase (AST), γ-glutamyl transpeptidase (γ-GT), total cholesterol (TC), triglyceride (TG), and high/low density lipoprotein cholesterol (H/LDL-C) content were measured; HE staining was used to observe the changes in liver structure, Western blot was used to detect the protein levels of PPARα, FAS and TNF-α in liver tissues, and mRNA expression profiles were analyzed by sequencing After RT-PCR, the mRNA expressions of miR-34a, PPARα, FAS, TNF-α and CPT-1 were verified. Results: Compared with K group, the hepatic cord disorder, focal lipid vacuum, obvious lipid droplet vacuolation, abnormal ectopic nucleus were observed in AFLD group ; liver function was decreased significantly. Compared with the M group, the liver functions of the ME and HE groups were improved significantly, the serum levels of TG, TC and LDL-C were decreased, while the HDL-C level was increased (P<0.01 or P<0.05), and the liver index and visceral fat ratio were decreased (P< 0.01 or P<0.05), the focal lipid droplet degeneration of hepatocytes was decreased, and the structure of the hepatic cord was clearer; and the ME group showed a more significant intervention effect. Compared with the M group, the expression levels of PPARα protein in the liver tissues of the LE, ME, and HE groups were increased, while the protein expression levels of FAS and TNF-α were decreased (P<0.01 or P<0.05). Based on Illumina high-throughput sequencing and mRNA differential expression analysis, there are 38 differentially expressed genes in the PPARα pathway, including 9 up-regulated genes and 29 down-regulated genes, which are involved in liver fatty acid oxidation, lipid metabolism, and apoptosis inhibition. Compared with group M, the gene levels of miR-34a, FAS, and TNF-α in LE, ME, and HE groups were decreased, and the gene levels of PPARα and CPT-1 were increased (P<0.01 or P<0.05). Conclusion: Swimming with different loads can improve liver functions in AFLD mice, promote lipid droplet degradation, and regulate liver lipid metabolism. The mechanism may be related to the activation of miR-34a/PPARα, and the intervention effect of moderate-load swimming is better.

Synergistic effects of trans-p-coumaric acid isolated from the ethanol extract of Gynura procumbens in promoting intestinal absorption of chlorogenic acid and reversing alcoholic fatty liver disease

Ethnopharmacological relevanceOur previous studies found that the ethanol extract of Gynura procumbens (EEGS) reduced hepatic steatosis in alcoholic fatty liver disease (AFLD). Aim of the studyTo explore the active ingredients from EEGS and their relevant mechanism of action in alleviating alcoholic liver injuries. Aim of the studyTo explore the active ingredients from EEGS and their intestinal absorption characteristics as an approach for understanding mechanism of action in alleviating alcoholic liver injuries. Materials and methodsMonitored by high-performance liquid chromatography (HPLC) and thin-layer chromatography (TLC), chemical constituents from the prepared EEGS were isolated by means of solvent extraction, repeated column chromatography, preparative HPLC and other methods, and their structures were identified based on spectroscopic methods. The in vivo intestinal absorption rate of chlorogenic acid (CA), the active component of the EEGS, both in a single form and in the EEGS were monitored by the single-pass intestinal perfusion (SPIP) method in rats. The protective effect of EEGS and its active components on alcoholic liver injuries was evaluated in the alcoholic liver injury model of C57BL/6J male mice induced by Lieber-DeCarli alcohol liquid feed. ResultsThree noncaffeoyl quinic acid components were isolated and identified from the EEGS, namely, 3-trans-p-coumaroyl quinic acid (0.9%), 3-cis-p-coumaroyl quinic acid (2.7%), and trans-p-coumaric acid (0.6%). In vivo intestinal absorption of CA decreased with the increase of pH value of perfusion solution in the range of 5.5–7.8. The maximum absorption percentage of CA alone was 6.7 ± 2.4%, while the maximum absorption percentage of CA in the EEGS was 16.0 ± 2.2%, which was 2.4 times higher than that of CA alone. The results of animal experiments showed that the degree of fatty liver of mice treated with EEGS was significantly lower than that of the CA, trans-p-coumaric acid, and the combination group of CA and trans-p-coumaric acid alone. ConclusionThe above results indicated that trans-p-coumaric acid isolated from the dried stems of Gynura procumbens assisted CA being absorbed into the body and worked together with CA to improve the function of liver lipid metabolism, reduce hepatic lipid accumulation in a mouse model of AFLD and effectively counteract alcohol-induced fatty liver disease.

Silencing miR-181b-5p upregulates PIAS1 to repress oxidative stress and inflammatory response in rats with alcoholic fatty liver disease through inhibiting PRMT1

ObjectiveThis study aimed to probe the function of microRNA-181b-5p (miR-181b-5p)/protein inhibitor of activated STAT1 (PIAS1)/protein arginine methyltransferase 1 (PRMT1) axis in the progression of alcoholic fatty liver disease (AFLD). MethodsA rat model of AFLD was established and treated with altered miR-181b-5p, PIAS1 or PRMT1 expression constructs to identify their effects on liver function, serum inflammation, liver tissue oxidative stress, hepatocyte apoptosis and pathological changes of liver tissue in rats using a series of assays. miR-181b-5p, PIAS1 and PRMT1 levels were detected, and the targeting relationship between miR-181b-5p and PIAS1 was confirmed. ResultsMiR-181b-5p and PRMT1 were elevated while PIAS1 was reduced in AFLD rat liver tissues, miR-181b-5p inhibition, PIAS1 overexpression or PRMT1 inhibition improved liver function, attenuated inflammation, oxidative stress, pathological changes and hepatocyte apoptosis in AFLD rat liver tissues. The impacts of miR-181b-5p inhibition on AFLD rats were reversed by PIAS1 silencing. PIAS1 was confirmed as a target gene of miR-181b-5p, and miR-181b-5p regulated PRMT1 expression through binding to PIAS1. ConclusionInhibiting miR-181b-5p can promote the expression of PIAS1, thereby inhibiting PRMT1 and ultimately improving AFLD.

Lipidomics and Redox Lipidomics Indicate Early Stage Alcohol-Induced Liver Damage.

Alcoholic fatty liver disease (AFLD) is characterized by lipid accumulation and inflammation and can progress to cirrhosis and cancer in the liver. AFLD diagnosis currently relies on histological analysis of liver biopsies. Early detection permits interventions that would prevent progression to cirrhosis or later stages of the disease. Herein, we have conducted the first comprehensive time‐course study of lipids using novel state‐of‐the art lipidomics methods in plasma and liver in the early stages of a mouse model of AFLD, i.e., Lieber‐DeCarli diet model. In ethanol‐treated mice, changes in liver tissue included up‐regulation of triglycerides (TGs) and oxidized TGs and down‐regulation of phosphatidylcholine, lysophosphatidylcholine, and 20‐22‐carbon‐containing lipid‐mediator precursors. An increase in oxidized TGs preceded histological signs of early AFLD, i.e., steatosis, with these changes observed in both the liver and plasma. The major lipid classes dysregulated by ethanol play important roles in hepatic inflammation, steatosis, and oxidative damage. Conclusion: Alcohol consumption alters the liver lipidome before overt histological markers of early AFLD. This introduces the exciting possibility that specific lipids may serve as earlier biomarkers of AFLD than those currently being used.

Astragaloside alleviates alcoholic fatty liver disease by suppressing oxidative stress.

Alcoholic fatty liver disease (AFLD) is the most common liver disease and can progress to fatal liver cirrhosis and carcinoma, affecting millions of patients worldwide. The functions of astragaloside on the cardiovascular system have been elucidated. However, its role in AFLD is unclear. Ethanol-treated AML-12 cells were used as a cell model of alcoholic fatty liver. Real-time quantitative reverse transcription-PCR and Western blotting detected genes and proteins expressions. Reactive oxygen species (ROS), triglyceride, total cholesterol, low-density lipoprotein, albumin, ferritin, bilirubin, superoxide dismutase, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) were examined using commercial kits. Lipid accumulation was assessed by Oil red O staining. MTT and flow cytometry measured cell viability and apoptosis. JC-1 was used to analyze mitochondrial membrane potential. A rat model of AFLD was established by treating rats with ethanol. Astragaloside suppressed ethanol-induced lipid accumulation, oxidative stress, and the production of AST and ALT in AML-12 cells. Ethanol induced TNF-α and reduced IL-10 expression, which were reversed by astragaloside. Ethanol promoted Bax expression and cytochrome C release and inhibited Bcl-2 and ATP expression. Astragaloside hampered these apoptosis effects in AML-12 cells. Impaired mitochondrial membrane potential was recovered by astragaloside. However, all these astragaloside-mediated beneficial effects were abolished by the ROS inducer pyocyanin. Ethanol-induced activation of NF-κB signaling was suppressed by astragaloside in vitro and in vivo, suggesting that astragaloside inhibited oxidative stress by suppressing the activation of NF-κB signaling, thus improving liver function and alleviating AFLD in rats. Our study elucidates the pharmacological mechanism of astragaloside and provides potential therapeutic strategies for AFLD.

Combined intake of blueberry juice and probiotics ameliorate mitochondrial dysfunction by activating SIRT1 in alcoholic fatty liver disease

BackgroundMitochondrial dysfunction has been implicated as a significant factor in the liver disease process. Blueberry juice and probiotics (BP) synergistically improve liver function in alcoholic fatty liver disease (AFLD), although the mechanism for this effect was unclear. This study aims to investigate the effect and specific mechanisms of BP on AFLD.MethodsC57/BL6 mice were randomly divided into seven groups: CG (control), MG (AFLD model), BJ (MG mice treated with blueberry), BJB (MG mice treated with BP), SI (AFLD mice treated with SIRT1 siRNA), BJSI (SI mice treated with blueberry), and BJBSI (SI mice treated with BP). The mice were fed an alcohol liquid diet for 10 days to establish the AFLD model, and subjected to BP and SIRT1 siRNA intervention for 10 days. Liver pathology was performed on day 11, and biochemical and molecular analyses of liver mitochondria were employed on day 12.ResultsBP significantly ameliorated hepatic mitochondrial injury, mitochondrial swelling, and hepatic necrosis in AFLD. BP alleviated hepatic mitochondrial dysfunction by increasing the expression of succinate dehydrogenase and cytochrome c oxidase, increasing respiratory control rate and the ADP/O ratio, and facilitating the synthesis of energy-related molecules. Besides, BP increased the expression of glutathione and superoxide dismutase, and inhibited malondialdehyde expression and reactive oxygen species activity. BP-induced sirtuin 1 (SIRT1), which activates peroxisome proliferator-activated receptor-gamma coactivator-1α, both of which mediate mitochondrial homeostasis. SIRT1 silencing suppressed the BP-induced changes in liver mitochondria, blunting its efficacy.ConclusionsThe ingredients of BP ameliorate hepatocyte mitochondrial dysfunction in AFLD mice.

Bioinformatics analysis of differentially expressed proteins in alcoholic fatty liver disease treated with recombinant human cytoglobin.

Cytoglobin (Cygb) is a globin molecule that is ubiquitously expressed in all tissues and has a protective role under oxidative stress. It has also been demonstrated to be effective in the treatment of alcoholic fatty liver disease (AFLD). In order to study the molecular mechanisms underlying its beneficial effects for the treatment of alcoholic liver, two-dimensional electrophoresis and mass spectrometric analysis were performed on serum and liver tissues from an in vivo rat model of AFLD. A total of 26 differentially expressed proteins were identified in the serum and 20 differentially expressed proteins were identified in liver specimens. Using online bioinformatics tools, it was indicated that these differentially expressed proteins were primarily associated with pathways including binding and uptake of ligands by scavenger receptors, response to corticosteroid, plasma lipoprotein remodeling, regulation of complement cascade, hydrogen peroxide catabolic process, as well as response to nutrient and monosaccharide. The present results suggested that recombinant human Cygb exerts its role in the treatment of AFLD primarily through affecting nutrient metabolism, monocarboxylic acid biosynthesis, regulation of glutathione expression, plasma lipoprotein remodeling and removal of metabolic waste from the blood.

Alcoholic fatty liver disease inhibited the co-expression of Fmo5 and PPAR\u03b1 to activate the NF-\u03baB signaling pathway, thereby reducing liver injury via inducing gut microbiota disturbance

BackgroundAlcohol-induced intestinal dysbiosis disrupts and inflammatory responses are essential in the development of alcoholic fatty liver disease (AFLD). Here, we investigated the effects of Fmo5 on changes in enteric microbiome composition in a model of AFLD and dissected the pathogenic role of Fmo5 in AFLD-induced liver pathology.MethodsThe expression profile data of GSE8006 and GSE40334 datasets were downloaded from the GEO database. The WGCNA approach allowed us to investigate the AFLD-correlated module. DEGs were used to perform KEGG pathway enrichment analyses. Four PPI networks were constructed using the STRING database and visualized using Cytoscape software. The Cytohubba plug-in was used to identify the hub genes. Western blot and immunohistochemistry assays were used to detect protein expression. ELISA assay was used to detect the levels of serum inflammatory cytokines. Lipid droplets in the cytoplasm were observed using Oil Red O staining. Apoptosis was detected using a TUNEL assay and flow cytometry analysis. ROS levels were detected using flow cytometry analysis. Nuclear translocation of NF-κB p65 was observed using immunofluorescence staining. Co-immunoprecipitation was used to detect the co-expression of PPARα and Fmo5 in L02 cells. 16S rDNA sequencing defined the bacterial communities in mice with AFLD.ResultsFmo5 is a key DEG and is closely associated with the gut microbiota and PPAR signaling pathway. Gut microbiome function in AFLD was significantly related to the PPAR signaling pathway. AFLD induced shifts in various bacterial phyla in the cecum, including a reduction in Bacteroidetes and increased Firmicutes. Fmo5 and PPARα co-expression in cell and animal models with AFLD, which decreased significantly. Silencing of Fmo5 and PPARα aggravated the functions of AFLD inducing apoptosis and inflammatory response, promoting liver injury, and activating the NF-κB signaling pathway in vivo and in vitro. The NF-κB inhibitor abolished the functions of silencing of Fmo5 and PPARα promoting AFLD-induced apoptosis, inflammatory response, and liver injury.ConclusionOur data indicated that the co-expression of Fmo5 and PPARα was involved in AFLD-related gut microbiota composition and alleviated AFLD-induced liver injury, apoptosis, and inflammatory response by inhibiting the nuclear translocation of NF-κB p65 to inhibit the NF-κB signaling pathway.

Protein Binding to Lipid Droplets with Altered Ratios of Surface Phospholipids

Alcoholic Fatty Liver Disease (AFLD) is characterized by an increase in lipid droplets in the liver after acute ingestion of alcohol. Previous experiments with a rat model of AFLD show hepatic lipid droplets contain altered levels of the predominant classes of phospholipids. Specifically, hepatic lipid droplets from AFLD rats were found with lower amounts of phosphatidylcholine (PC) relative to phosphatidylethanolamine (PE). Our experiments aim to determine if the altered phospholipid composition of AFLD lipid droplets causes differences in the numbers or types of lipid droplet‐associated proteins. We selected proteins based on their membrane binding motifs and roles in lipid droplet homeostasis. AML12 cells cultured in choline‐deficient media simulate the altered phospholipid composition of AFLD lipid droplets. We isolated lipid droplets from AML12 cells cultured with and without choline and examined proteins of interest by SDS‐PAGE and western blotting. We found equivalent levels of rab18 and lanosterol synthase in lipid droplet fractions from cells grown with and without choline. Alternatively, perilipin 1, perilipin 2, and CIDE‐C are predominantly found in lipid droplet fractions from cells grown without choline (with lower ratios of PC:PE). The proteins that are most influenced by lipid droplet surface composition are all predicted to associate with lipid droplets through amphipathic alpha helices. By evaluating how altered phospholipid monolayer composition affects the binding of lipid droplet proteins, we seek to further elucidate the biochemical pathways that contribute to AFLD.Support or Funding InformationThis research was supported by St. Olaf College and the TRIO McNair Scholars Program.

Lipid Droplet Protein Binding in Response to Altered Phospholipid Composition

Alcoholic Fatty Liver Disease (AFLD) is the alcohol‐induced accumulation of excess lipids in hepatocyte lipid droplets. Lipid droplet surfaces are phospholipid monolayers predominantly composed of phosphatidylcholine (PC) and phosphatidylethanolamine (PE). Protein binding to lipid droplets affects droplet size and activity. Previous experiments with a rat model of AFLD show lipid droplet surfaces have a decreased ratio of PC:PE. We aimed to determine if the altered phospholipid composition of AFLD lipid droplets leads to differential binding of several proteins of interest, selected for their membrane binding motifs and roles in lipid droplet homeostasis. By culturing AML12 cells in choline‐deficient media with oleate, an unsaturated fatty acid, we simulated the altered phospholipid composition of AFLD lipid droplets. Next, we isolated lipid droplet fractions and examined proteins of interest by SDS‐PAGE and western blotting. We found equivalent levels of rab18 and lanosterol synthase associating with lipid droplet fractions from cells grown with and without choline. Alternatively, there was an increase in the level of αCCT1 and perilipin 2 in lipid droplet fractions from cells grown without choline. By evaluating how altered phospholipid monolayer composition affects the binding of lipid droplet proteins, we seek to further elucidate the biochemical pathways that contribute to AFLD.Support or Funding InformationThis work was supported by St. Olaf College Collaborative Undergraduate Research and Inquiry, Howard Hughes Medical Institute, the St. Olaf TRIO McNair Scholars Program, and LSAMP Alliance.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Decreasing Phosphatidylcholine on the Surface of the Lipid Droplet Correlates with Altered Protein Binding and Steatosis.

Alcoholic fatty liver disease (AFLD) is characterized by an abnormal accumulation of lipid droplets (LDs) in the liver. Here, we explore the composition of hepatic LDs in a rat model of AFLD. Five to seven weeks of alcohol consumption led to significant increases in hepatic triglyceride mass, along with increases in LD number and size. Additionally, hepatic LDs from rats with early alcoholic liver injury show a decreased ratio of surface phosphatidylcholine (PC) to phosphatidylethanolamine (PE). This occurred in parallel with an increase in the LD association of perilipin 2, a prominent LD protein. To determine if changes to the LD phospholipid composition contributed to differences in protein association with LDs, we constructed liposomes that modeled the LD PC:PE ratios in AFLD and control rats. Reducing the ratio of PC to PE increased the binding of perilipin 2 to liposomes in an in vitro experiment. Moreover, we decreased the ratio of LD PC:PE in NIH 3T3 and AML12 cells by culturing these cells in choline-deficient media. We again detected increased association of specific LD proteins, including perilipin 2. Taken together, our experiments suggest an important link between LD phospholipids, protein composition, and lipid accumulation.

Therapeutic hexapeptide (PGPIPN) prevents and cures alcoholic fatty liver disease by affecting the expressions of genes related with lipid metabolism and oxidative stress.

PGPIPN is a therapeutic hexapeptide derived from bovine β-casein. Here we investigated the role and mechanism of this peptide on alcoholic fatty liver disease (AFLD). We took human hepatic cell line LO2 and hepatocellular carcinoma cell line HepG2 to establish the models of steatosis hepatocyte induced by alcohol, taken PGPIPN as pharmacological intervention. And we also established the model of AFLD mice, taken PGPIPN as therapeutic drug and glutathione (GSH) as positive control. We assayed the biochemical materials related to liver injury, lipid metabolism and oxidation, and observed morphology change and fat accumulation of hepatocyte. The gene expressions and/or activities related to liver injury, lipid metabolism and oxidation, such as ACC, PPAR-γ, CHOP and Caspase-3, were assessed by real time PCR and western blot. Our results showed PGPIPN alleviated hepatic steatosis in both model cells and AFLD model mice. PGPIPN can effectively reduce the lipid accumulation and oxidative stress of hepatocyte in a dose-dependent manner. PGPIPN alleviated alcohol-induced cell steatosis and injuries by regulating the gene expressions and/or activities of ACC, PPAR-γ, CHOP and Caspase-3. Our results demonstrated PGPIPN had the protective and therapeutic effect on AFLD, which may serve as a potential therapeutic agent for AFLD.

Protein interaction mapping interpretation of none alcoholic fatty liver disease model of rats after fat diet feeding.

This study investigates the effect of fat diet on gene expression profile in rat liver via protein-protein interaction mapping analysis. Nonalcoholic fatty liver disease (NAFLD) is a prevalent condition of liver in the world. This progressive metabolic disease is representative with fat accumulation in the patients' liver that can led to advance stages, namely, cirrhosis and eventually cancer. Differentially expressed genes of NAFLD rat liver after 2, 4 and 6 weeks fat diet feeding were analyzed via GEO2R and protein-protein interaction network by Cytoscape v3.6.0. and the related plug-ins. The important genes were assigned based on degree and betweenness centrality analysis and enriched using ClueGO+CluePedia Plug-in. GAPDH, PRDM10, TP53, AKT1, INS, ALB, SRC, MAPK1, ACLY, ACACA, DECR1, ACACB, MBOAT4, TNF, EHHADH and JUN genes were introduced as key genes related to the fat diet fed NAFLD rats. Fatty acid biosynthesis and four other terms were introduced as the main related ones to the essential genes. The introduced critical genes and the related terms may describe NAFLD molecular condition and its progression to the other severe metabolic diseases. Moreover, these potential biomarkers may be monitored for diagnosis and treatment approaches after validation investigations.

Establishment of an alcoholic fatty liver disease model in mice

ABSTRACTBackground: Alcoholic fatty liver disease (AFLD) defines an important stage in the progression of alcoholic liver disease (ALD), which is a major cause of morbidity and mortality worldwide. Objective: To establish a mouse model of AFLD. Methods: Male C57BL/6 mice were divided into the following two groups: (i) a control group, which was allowed free access to food and water and (ii) an alcohol-treated group, which was administered a 15% (v/v) alcohol solution instead of water. After 8–9 months of treatment, serum biochemical indexes, histopathological changes, liver triglyceride content, iron storage, and ferritin light chain protein expression were measured using an automatic biochemical analyzer, hematoxylin–eosin (HE) staining, a commercially available kit, Prussian blue staining, and Western blot analysis, respectively. Results: Compared with the control group, the alcohol-treated group displayed increased levels of serum LDH, ALT, and AST, decreased levels of ALB, and no significant change in levels of TP. Additionally, increased levels of serum TG, T-CHO, and LDL and decreased levels of serum GLU and HDL were observed in the alcohol-treated mice. HE staining showed that lipid vacuolization occurred in the livers of alcohol-treated mice. The alcohol-treated mice also exhibited increased liver triglyceride content. Moreover, Prussian blue staining and Western blot analysis demonstrated that chronic alcohol administration caused iron overloading of the liver. Conclusions: Chronic administration of 15% (v/v) alcohol in the drinking water over 8–9 months caused AFLD in mice. Our results establish an AFLD model that represents a promising tool for the future study of the progression of ALD.

Taurine accelerates alcohol and fat metabolism of rats with alcoholic Fatty liver disease.

Liver is considered to be the main organ capable of oxidizing alcohol and fat. Chronic consumption of alcohol is the major cause of liver injury and the development of alcoholic fatty liver disease (AFLD). Liver is also the main organ capable of synthesizing taurine, and the effects of taurine on liver disease have aroused great attention. In the present study, alcohol and pyrazole were administered to male Wistar rats by way of intragastric administration and combined with a high fat diet in order to establish the AFLD model. Taurine was administered in the drinking water during and after the establishment of the AFLD model. The preventive experiment lasted for 12 weeks. The curative experiment was divided into 4 and 8 weeks. Hepatic activities of ADH, ALDH, serum ALT, AST, TC, TG, HDL-C, LDL-C, NEFA and hepatic NEFA were measured. The results showed that hepatic ADH and ALDH in AFLD rats were significantly lower while serum ALT, AST, TC, TG, LDL-C, NEFA and hepatic NEFA in model group were significantly higher than normal rats (P < 0.05), and serum HDL-C was obviously lower. Serum ALT, AST, TC, TG, LDL-C, NEFA, and hepatic NEFA were decreased in taurine preventive and curative groups (P < 0.05), while hepatic activities of ADH and ALDH, serum HDL-C were significantly increased in taurine groups (P < 0.05). Observation of the pathological sections showed that taurine can significantly attenuate fatty degeneration and the deposition of the liver caused by alcohol. The results indicated that taurine presumably accelerates the metabolism of alcohol and fat in the liver, thereby inhibiting and reversing hepatic fatty degeneration in AFLD rats.

Zeaxanthin dipalmitate therapeutically improves hepatic functions in an alcoholic fatty liver disease model through modulating MAPK pathway.

In the current study, the therapeutic effects of zeaxanthin dipalmitate (ZD) on a rat alcoholic fatty liver disease (AFLD) model were evaluated. After-treatment with ZD from the 5th week to the 10th week in a 10-week ethanol intragastric administration in rats significantly alleviated the typical AFLD symptoms, including reduction in rat body weight, accumulation of hepatic fat droplets, occurrence of oxidative stress, inflammation, chemoattractive responses and hepatic apoptosis in the liver. The reduction of liver function abnormalities by ZD was partly through lower expression level of cytochrome P450 2E1 (CYP2E1), diminished activity of nuclear factor kappa B (NF-κB) through the restoration of its inhibitor kappa B alpha (IκBα), and the modulation of MAPK pathways including p38 MAPK, JNK and ERK. ZD treatment alone did not pose obvious adverse effect on the healthy rat. In the cellular AFLD model, we also confirmed the inhibition of p38 MAPK and ERK abolished the beneficial effects of ZD. These results provide a scientific rationale for the use of zeaxanthin and its derivatives as new complementary agents for the prevention and treatment of alcoholic liver diseases.

Changes in the intestinal microenvironment during development of alcoholic fatty liver disease and related effects of probiotic therapy

To investigate the initial changes in the gut microenvironment that accompany intestinal endotoxemia related to alcoholic fatty liver disease (ALD) in order to explore the potential initiating factors and to observe the effect of probiotic therapy on these factors. Fifty Sprague-Dawley male rats were randomly divided into an ALD model group (alcoholic intragastric administration), an intervention group (ALD with probiotic intragastric administration), and a control group (physiological saline intragastric administration). Histological changes of the liver were evaluated using hematoxylin-eosin staining and light microscopy. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and triglycerides (TG), and plasma endotoxin and coli bacillus were determined. The structural integrity of intestinal mucosa and tight junctions were observed by transmission electron microscopy. Occludin protein expression in intestinal epithelial cells was detected by immunohistochemistry. After four weeks, the three groups showed significant differences in the plasma endotoxin levels [control: (0.67+/-0.14) pg/ml, model: (4.42+/-1.28) pg/ml, and intervention: (2.88+/-0.83) pg/ml; F = 27.288, P = 0.000] and numbers of Escherichia coli [control: (2.31+/-0.39) lg3/ml, model: (3.23+/-0.41) lg3/ml, and intervention: (2.24+/-0.44) lg3/ml; F = 10.692, P = 0.001]. The plasma endotoxin level and E. coli number were significantly higher in the model group than in the control group and the intervention group (all P less than 0.05). The three groups showed no significant differences in the levels of ALT, AST, and TG at four weeks. After eight weeks, however, all three serum markers were significantly different between the three groups [ALT: control: (62.33+/-7.12) U/L, model: (95.50+/-8.73) U/L, and intervention: (81.33+/-6.19) U/L; F = 18.051, P = 0.000]; [AST: control: (90.50+/-10.67) U/L, model: (130.00+/-14.91) U/L, and intervention: (110.33+/-7.26) U/L; F = 30.170, P = 0.000]; [TG: control: (0.84+/-0.84) mmol/L, model: (1.40+/-0.17) mmol/L, and intervention: (1.10+/-0.17) mmol/L; F = 10.592, P = 0.001]. In addition, the three groups showed significant differences in E. coli number [control: (2.23+/-0.46) lg3/ml, model: (4.81+/-0.29) lg3/ml, and intervention: (3.61+/-0.50) lg3/ml; F = 23.579, P = 0.000] and plasma endotoxin level [control: (0.52+/-0.21) pg/ml, model: (12.46+/-2.61) pg/ml, intervention: (6.83+/-1.74) pg/ml; F = 30.731, P = 0.000]. The levels of ALT, AST, TG and endotoxin, and the number of E. coli were all significantly higher in the model group than in the control group and the intervention group (all P less than 0.05). Small intestinal epithelial cell structural failure was more apparent and intercellular gaps more broad after eight weeks than after four weeks for all three groups. However, the intervention group showed clearer cell connection structures and less extensive cell gap broadening than the model group at eight weeks. After eight weeks, the occludin protein had become significantly down-regulated and distributed in a non-continuous pattern in the model group, as compared with the control group. However, the occludin protein expression was higher in intervention group than in the model group. Intestinal endotoxemia related to perturbations in the microenvironment occurs in the early phase of ALD, and the increased intestinal permeability appears to be the initial factor of elevated plasma endotoxin, which may lead to liver damage. Probiotic therapy can reduced plasma endotoxin levels and postpone ALD progression by altering the composition of the gut microbiota and up-regulating expression of the occludin protein in intestinal epithelial cells.