OBJECTIVETo establish nonalcoholic fatty liver disease (NAFLD) model induced by free fatty acid (FFA) and iron, and to explore the synergistic effect of FFA and Fe(2+) on the pathogenesis of NAFLD and mechanisms.

METHODSHuman liver carcinoma cell HepG2 was respectively treated with 0.250, 0.500, 1.000 mmol/L oleic acid, 0.500 mmol/L oleic acid+0.125 mmol/L Fe(2+), 0.500 mmol/L oleic acid+0.250 mmol/L Fe(2+), and 0.500 mmol/L oleic acid+0.500 mmol/L Fe(2+). Human liver carcinoma cell HepG2 was normally cultured in the control group. Lipid accumulation of cells were observed by oil red O staining and the determination of the triglyceride (TG) contents by GPO-PAP, then the expression of key genes involved in fatty acid β-oxidation (fatty acyl CoA synthetase-1 (ACSL-1), carnitine acyl transferase 1 (CPT-1a), fatty acid synthetase (FAS)) was determined using RT-PCR. The differences of TG content and ACSL-1, CPT-1a, FAS, mRNA relative value were analyzed among different groups.

RESULTSThe results of oil red O staining indicated that the contents of lipid droplets were obviously elevated with the increase of Fe(2+) concentration in human liver carcinoma cell HepG2 treated with 0.500 mmol/L oleic acid and different concentrations of Fe(2+). The TG contents of HepG2 cell in control group, 0.250, 0.500, 1.000 mmol/L oleic acid groups, 0.500 mmol/L oleic acid+0.125 mmol/L Fe(2+) group, 0.500 mmol/L oleic acid+0.250 mmol/L Fe(2+) group, 0.500 mmol/L oleic acid+0.500 mmol/L Fe(2+) group respectively were (90.0 ± 1.6), (131.7 ± 5.4), (153.7 ± 3.0), (254.1 ± 4.0), (164.5 ± 6.0), (180.1 ± 7.7), (235.6 ± 4.5) nmol/mg (F = 396.00, P < 0.05). The expression levels of ACSL-1 mRNA in 0.500 mmol/L oleic acid group, 0.500 mmol/L oleic acid+0.125 mmol/L Fe(2+) group, 0.500 mmol/L oleic acid +0.250 mmol/L Fe(2+) group, 0.500 mmol/L oleic acid +0.500 mmol/L Fe(2+) group respectively were (0.94 ± 0.02), (0.89 ± 0.04), (0.85 ± 0.02), (0.74 ± 0.04) (F = 50.00, P < 0.05); the mRNA levels of CPT-1a were (0.89 ± 0.03), (0.79 ± 0.05), (0.67 ± 0.04), (0.51 ± 0.05) (F = 79.00, P < 0.05); the mRNA levels of FAS were (1.31 ± 0.05) , (1.44 ± 0.03), (1.51 ± 0.05), (1.56 ± 0.06 ) (F = 79.70, P < 0.05).

CONCLUSIONThe NAFLD liver cell model could be established by oleic acid and Fe(2+) in HepG2 cells. FFA and iron might be involved in the pathogenesis of NAFLD through the intervention of fatty acid β-oxidation.

Carnitine O-Palmitoyltransferase ; Coenzyme A Ligases ; Fatty Acid Synthase, Type I ; Fatty Acids ; Fatty Acids, Nonesterified ; adverse effects ; Hep G2 Cells ; Humans ; Iron ; adverse effects ; Non-alcoholic Fatty Liver Disease ; chemically induced ; Oleic Acid ; RNA, Messenger ; Triglycerides

BACKGROUNDNonalcoholic fatty liver disease (NAFLD) has emerged as the major cause of chronic liver injury. Intestinal barrier plays an important role in the pathogenis of NAFLD. The aim of this article was to assess intestinal immune barrier function during the development of NAFLD.

METHODSTotally 60 male Sprague-Dawley (SD) rats were divided into 2 groups: normal diet (ND) group and high-fat diet (HFD) group. NAFLD rat model was established in the HFD rat group. Portal blood endotoxin level was assessed by limulus test. The percentage of CD4+ cells and CD8+ cells in peripheral blood mononuclear cells (PBMC) and lymphocytes in Peyer's patches (PP) were analysed by flow cytometry. Intestinal secretory immunoglobulin A (SIgA) level was evaluated by enzyme-linked immunosorbent assay. Paired Student's t test was used for the statistic analysis.

RESULTSHFD rats presented with simple steatosis at the 4th and 8th week and progressed to nonalcoholic steatohepatitis at the 12th week. Elevated lipopolysaccharides (LPS) level in HFD rats was observed at the 8th week ((1.54 ± 0.30) times of ND group, P < 0.01). CD4/CD8 ratios in PBMC and PP of HFD rats were increased at the 4th week ((1.50 ± 0.47) and (1.63 ± 0.34) times of ND group, P < 0.05) and decreased at the 8th week ((0.50 ± 0.16) and (0.61 ± 0.26) times of ND group, P < 0.05). At the 12th week, CD4/CD8 ratio ((1.47 ± 0.46) times, P < 0.05) in PP increased to levels observed in the 4th week. Intestinal SIgA expression of HFD rats was remarkably up-regulated at 12th week ((2.70 ± 1.65) times, P < 0.05).

CONCLUSIONLiver-gut axis in rats with NAFLD may mediate and improve intestinal immune function by increased CD4/CD8 ratio in PP and increased production of SIgA.

Animals ; CD4-Positive T-Lymphocytes ; immunology ; CD8-Positive T-Lymphocytes ; immunology ; Diet, High-Fat ; adverse effects ; Disease Models, Animal ; Fatty Liver ; chemically induced ; etiology ; immunology ; Immunoglobulin A, Secretory ; immunology ; Intestines ; immunology ; Male ; Non-alcoholic Fatty Liver Disease ; Rats ; Rats, Sprague-Dawley

OBJECTIVEOur previous study indicated that the death receptor Fas played a key role on hepatocyte apoptosis in nutritional steatohepatitis in mice. This study aimed to explore whether Fas mutation accelerated hepatic steatosis and inflammatory infiltration in methionine-choline deficient (MCD) diet feeding mice.

METHODSMice homozygous for the lymphoproliferation spontaneous mutation (C57BL/6J-Faslpr) and wild type C57BL/6J mice were fed with MCD diet for three weeks to induce non-alcoholic steatohepatitis (NASH). Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), triglyceride (TG) and total cholesterol (TC) levels were detected by an Olympus AU5400 automatic chemical analyzer. The role of Fas gene mutation on NASH was assessed by comparing the severity of hepatic steatosis and inflammation in the liver sections, the mRNA and protein expressions of hepatic inflammatory and fibrogenesis related factors, proliferating cell nuclear antigen (PCNA) and transforming growth factor beta 1 (TGFb1).

RESULTSThe serum ALT levels of the wild type and Faslpr mice fed with MCD were significant higher than that of the control mice (126.33+/-10.50 U/L vs (25.00+/-10.14) U/L, (160.33+/-48.29) U/L vs (18.33+/-9.08) U/L, with the LSD-t value 12.02, 5.08 respectively, the P value<0.001, 0.007 respectively. The serum ALT levels showed no significant difference between the Faslpr and wild type mice fed with MCD, with the LSD-t value 1.19, the P value 0.229. The serum AST, TG and TC levels showed neithere significant difference among the four groups. MCD diet induced hepatic steatosis and inflammatory infiltration in both of the wild type and Faslpr mice. Especially, severer hepatic injury was observed in Faslpr mice as compared with wild type mice. The mRNA expression levels of cell proliferation factor PCNA and fibrogenesis growth factor TGF b1 in wild type mice fed with MCD were significantly higher than that of the control mice (2.84+/-0.73, 2.77+/-0.54 vs 1.31+/-0.18, 0.89+/-0.18), with the LSD-t value 4.99, 8.08 respectively, the P value 0.001, <0.001 respectively. The mRNA expression levels of PCNA and TGFb1 in Faslpr mice fed with MCD were significantly higher than that of the Faslpr control mice and the wild type mice fed with MCD (5.57+/-1.13, 5.73+/-0.89 vs 1.04+/-0.16, 0.85+/-0.11 and 2.84+/-0.73, 2.77+/-0.54), with the LSD-t value 10.15, 13.19 and 5.33, 6.91 respectively, the P value<0.001. The protein expressions levels of PCNA and TGFb1 were concordant with the mRNA.

CONCLUSIONSFaslpr promoted hepatic steatosis and inflammatory infiltration in mice fed with MCD diet, which might associated with excessive release of cell proliferative, inflammatory and fibrogenesis factors.

Animals ; Fatty Liver ; chemically induced ; genetics ; Male ; Mice ; Mice, Inbred C57BL ; Mutation ; Non-alcoholic Fatty Liver Disease ; Proliferating Cell Nuclear Antigen ; metabolism ; Transforming Growth Factor beta1 ; metabolism ; fas Receptor ; genetics

OBJECTIVES: Long-term treatment of olanzapine, the most widely-prescribed second-generation antipsychotic, remarkably increases the risk of non-alcoholic fatty liver disease (NAFLD), whereas the mechanism for olanzapine-induced NAFLD remains unknown. Excessive hepatic fat accumulation is the basis for the pathogenesis of NAFLD, which results from the disturbance of TG metabolism in the liver. Apolipoprotein A5 (ApoA5) is a key regulator for TG metabolism in vivo that promotes TG accumulation in hepatocytes, thereby resulting in the development of NAFLD. However, there are no data indicating the role of apoA5 in olanzapine-induced NAFLD. Therefore, this study aims to investigate the role of apoA5 in olanzapine-induced NAFLD. METHODS: This study was carried out via animal studies, cell experiment, and ApoA5 gene knockdown experiment. Six-week-old male C57BL/6J mice were randomized into a control group, a low-dose group, and a high-dose group, which were treated by 10% DMSO, 3 mg/(kg·d) olanzapine, and 6 mg/(kg·d) olanzapine, respectively for 8 weeks. The lipid levels in plasma, liver function indexes, and expression levels of ApoA5 were detected. HepG2 cells were treated with 0.1% DMSO (control group), 25 μmol/L olanzapine (low-dose group), 50 μmol/L olanzapine (medium-dose group), and 100 μmol/L olanzapine (high-dose group) for 24 h. HepG2 cells pretreated with 100 μmol/L olanzapine were transfected with siRNA and scrambled siRNA (negative control), respectively. We observed the changes in lipid droplets within liver tissues and cells using oil red O staining and fat deposition in liver tissues using HE staining. The mRNA and protein levels of ApoA5 were determined by real-time PCR and Western blotting, respectively. RESULTS: After intervention with 3 and 6 mg/(kg·d) olanzapine for 8 weeks, there was no significant difference in body weight among the 3 groups (P>0.05). Olanzapine dose-dependently increased the plasma TG, ALT and AST levels, and reduced plasma ApoA5 levels (all P<0.05), whereas there was no significant difference in plasma cholesterol (HDL-C, LDL-C, and TC) levels among the 3 groups (all P>0.05). Olanzapine dose-dependently up-regulated ApoA5 protein levels in liver tissues (all P<0.05), but there was no significant change in ApoA5 mRNA expression among groups (P>0.05). In the control group, the structure of liver tissues was intact, the morphology of liver cells was regular, and only a few scattered lipid droplets were found in the cells. In the olanzapine-treated group, there was a large amount of lipid deposition in hepatocytes, and cells were balloon-like and filled with lipid droplet vacuoles. The nucleus located at the edge of cell, and the number of lipid droplets was increased significantly, especially in the high-dose group. Likewise, when HepG2 cells were treated with olanzapine for 24 h, the number and size of lipid droplets were significantly elevated in a dose-dependent manner. Moreover, olanzapine dose-dependently up-regulated ApoA5 protein levels in HepG2 cells (all P<0.05), but there was no significant difference in ApoA5 mRNA expression among groups (P>0.05). Compared with the HepG2 cells transfected with scrambled siRNA, the number and size of lipid droplets in HepG2 cells transfected with ApoA5 siRNA were significantly reduced. CONCLUSIONS The short-term intervention of olanzapine does not significantly increase body weight of mice, but it can directly induce hypertriglyceridemia and NAFLD in mice. Olanzapine inhibits hepatic apoA5 secretion but does not affect hepatic apoA5 synthesis, resulting in the pathogenesis of NAFLD. Inhibition of apoA5 secretion plays a key role in the development of olanzapine-related NAFLD, which may serve as an intervention target for this disease.
Animals ; Apolipoprotein A-V/genetics* ; Body Weight ; Dimethyl Sulfoxide/metabolism* ; Liver/metabolism* ; Male ; Mice ; Mice, Inbred C57BL ; Non-alcoholic Fatty Liver Disease/chemically induced* ; Olanzapine/metabolism* ; RNA, Messenger/metabolism* ; RNA, Small Interfering ; Triglycerides

This study is to evaluate the therapeutic effect of fibroblast growth factor 21 (FGF21) on NAFLD in MSG-IR mice and to provide mechanism insights into its therapeutic effect. The MSG-IR mice with insulin resistance were treated with high dose (0.1 micromol.kg-1d-1) and low dose (0.025 micromol.kg-1d-1) of FGF21 once a day for 5 weeks. Body weight was measured weekly. At the end of the experiment, serum lipids, insulin and aminotransferases were measured. Hepatic steatosis was observed. The expression of key genes regulating energy metabolism were detected by real-time PCR. The results showed that after 5 weeks treatment, both doses of FGF21 reduced body weight (P<0.01), corrected dyslipidemia (P<0.01), reversed steatosis and restored the liver morphology in the MSG model mice and significantly ameliorated insulin resistance. Additionally, real-time PCR showed that FGF21 significantly reduced transcription levels of fat synthetic genes, decreased fat synthesis and promoted lipolysis and energy metabolism by up-regulating key genes of lipolysis, thereby liver fat accumulation was reduced and liver function was restored to normal levels. In conclusion, FGF21 significantly reduces body weight of the MSG-IR mice, ameliorates insulin resistance, reverses hepatic steatosis. These findings provide a theoretical support for clinical application of FGF21 as a novel therapeutics for treatment of NAFLD.
Animals ; Body Weight ; drug effects ; Dose-Response Relationship, Drug ; Dyslipidemias ; metabolism ; Energy Metabolism ; drug effects ; Fatty Liver ; chemically induced ; complications ; Female ; Fibroblast Growth Factors ; administration & dosage ; pharmacology ; therapeutic use ; Insulin Resistance ; Lipolysis ; drug effects ; Liver ; metabolism ; pathology ; Male ; Mice ; Non-alcoholic Fatty Liver Disease ; drug therapy ; Sodium Glutamate

Nonalcoholic fatty liver disease (NAFLD) and type 2 Diabetes Mellitus (T2DM) are highly prevalent diseases and are closely associated, with NAFLD being present in the majority of T2DM patients. In Asian traditional medicine, Mori Cortex is widely used for the treatment of diabetes and hyperlipidemia. However, whether it has a therapeutic effect on T2DM associated with NAFLD is still unknown. The present study showed that the oral treatment with Mori Cortex extract (MCE; 10 g·kg·d) lowered the blood lipid levels and reversed insulin resistance (IR) in high fat-diet/streptozotocin-induced type 2 diabetes in rats. The expression levels of sterol receptor element-binding protein-1c (SREBP-1c) and carbohydrate-responsive element binding protein (ChREBP), which are involved in steatosis in NAFLD rats, were measured in the liver samples. MCE decreased the protein and mRNA expression levels of SREBP-1c and ChREBP. In conclusion, down-regulation of SREBP-1c and ChREBP might contribute to the protective effect of MCE on hepatic injury and IR in the rats with T2DM associated with NAFLD.
Alanine Transaminase ; blood ; Animals ; Aspartate Aminotransferases ; blood ; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors ; genetics ; Diabetes Mellitus, Type 2 ; blood ; chemically induced ; drug therapy ; metabolism ; Diet, High-Fat ; adverse effects ; Disease Models, Animal ; Down-Regulation ; drug effects ; Insulin ; blood ; Insulin Resistance ; physiology ; Lipid Metabolism ; drug effects ; genetics ; Liver ; drug effects ; physiopathology ; Male ; Morus ; Non-alcoholic Fatty Liver Disease ; blood ; chemically induced ; drug therapy ; metabolism ; Phytotherapy ; Plant Extracts ; pharmacology ; therapeutic use ; Rats ; Rats, Sprague-Dawley ; Streptozocin