High-fat emulsion-induced rat model of nonalcoholic steatohepatitis

Liquorice root extract and isoliquiritigenin attenuate high-fat diet-induced hepatic steatosis and damage in rats by regulating AMPK

Objective: This study compared the ability of Liquorice roots aqueous extract (LRE) and its ingredient, isoliquiritigenin (ISL), in alleviating high-fat diet (HFD)-induced hepatic steatosis and examined if this effect involves activation of AMPK.Materials and methods: Control or HFD-fed rats were treated with the vehicle, LRE (200 mg/kg), or ISL (30 mg/kg) for 8 weeks orally.Results: ISL and LRE reduced HFD-induced hyperglycaemia, improved liver structure, lowered serum and hepatic lipids, and attenuated hepatic oxidative stress and inflammation. In the control and HFD-fed rats, ISL and LRE significantly stimulated the muscular and hepatic mRNA and protein levels of AMPK, improved oral glucose tolerance, reduced hepatic mRNA levels of SREBP1/2, and upregulated hepatic levels of PPARα and Bcl2. These effects were comparable for ISL and LRE and were prevented by co-administration of compound C, an AMPK inhibitor.Discussion and conclusion: ISL and LRE provide an effective theory to alleviate hepatic steatosis through activating AMPK.

Bilirubin, once a toxin but now an antioxidant alleviating non-alcoholic fatty liver disease in an autophagy-dependent manner in high-fat diet-induced rats: a molecular and histopathological analysis

Background and purpose

As an endogenous antioxidant, bilirubin has surprisingly been inversely correlated with the risk of non-alcoholic fatty liver disease (NAFLD). Thereupon, the current evaluation was designed to assess the positive effects of bilirubin on the autophagy flux, as well as the other pathogenic processes and parameters involved in the expansion of NAFLD.

Experimental approach

Thirty adult male rats weighing 150-200 g with free access to sucrose solution (18%) were randomly subdivided into 5 groups (n = 6). Subsequently, the animals were euthanized, and their blood specimens and liver tissue samples were collected to measure serum biochemical indices, liver histopathological changes, intrahepatic triglycerides content, and tissue stereological alterations. Furthermore, the expression levels of autophagy-related genes (Atgs) were measured to assess the state of the autophagy flux.

Findings/Results

Fasting blood glucose, body weight, as well as liver weight, liver-specific enzyme activity, and serum lipid profile indices markedly decreased in rats that underwent a six-week bilirubin treatment compared to the control group. In addition, histopathological studies showed that hepatic steatosis, fibrosis, inflammation, and necrosis significantly decreased in the groups that received bilirubin compared to the control animals. Bilirubin also caused significant alterations in the expression levels of the Atgs, as well as the Beclin- 1 protein.

Conclusion and implication

Bilirubin may have potential ameliorative effects on NAFLD-associated liver damage. Moreover, the beneficial effects of bilirubin on intrahepatic lipid accumulation and steatosis were comparable with the group that did not ever receive bilirubin.

Protective and curative effects of unconjugated bilirubin on gene expression of LOX-1 and iNOS in the heart of rats receiving high-fat diet and low dose streptozotocin: a histomorphometric approach

BACKGROUND

Atherosclerosis is a chronic inflammatory condition affecting the large arteries and is a major cause of cardiovascular diseases (CVDs) globally. Increased levels of adhesion molecules in cardiac tissue serve as prognostic markers for coronary artery occlusion risk. Given the antioxidant properties of bilirubin and its inverse correlation with atherosclerosis, this study aimed to assess the beneficial effects of bilirubin on atherosclerotic indices and heart structure in high-fat diet-fed diabetic rats with atherosclerosis.

METHODS

Atherosclerosis was induced in three out of five groups of adult male Sprague Dawley rats through a 14-week period of high-fat diet (HFD) consumption and a single low dose of streptozotocin (STZ) (35 mg/kg). The atherosclerotic rats were then treated with intraperitoneal administration of 10 mg/kg/day bilirubin for either 6 or 14 weeks (treated and protected groups, respectively), or the vehicle. Two additional groups served as the control and bilirubin-treated rats. Subsequently, the mRNA expression levels of vascular cell adhesion molecule 1 (VCAM-1), intercellular adhesion molecule 1 (ICAM-1), lectin-like LDL receptor 1 (LOX-1), and the inducible nitric oxide synthase (iNOS) were analyzed using quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). Histopathological and stereological analyses were performed to assess changes in the heart structure.

RESULTS

Bilirubin significantly decreased the expression of VCAM-1, ICAM-1, LOX-1, and iNOS genes in the treated group. Moreover, bilirubin mitigated pathological damage in the left ventricle of the heart. Stereological analysis revealed a decrease in the left ventricle and myocardium volume, accompanied by an increase in vessel volume in rats treated with bilirubin.

CONCLUSION

These findings demonstrate that mild hyperbilirubinemia can protect against the progression of atherosclerosis and heart failure by improving lipid profile, modulating adhesion molecules, LOX-1, and iNOS gene expression levels.

Esculeogenin A, a Glycan from Tomato, Alleviates Nonalcoholic Fatty Liver Disease in Rats through Hypolipidemic, Antioxidant, and Anti-Inflammatory Effects

This study examined the preventative effects of esculeogenin A (ESGA), a newly discovered glycan from tomato, on liver damage and hepatic steatosis in high-fat-diet (HFD)-fed male rats. The animals were divided into six groups (each of eight rats): a control group fed a normal diet, control + ESGA (200 mg/kg), HFD, and HFD + ESAG in 3 doses (50, 100, and 200 mg/kg). Feeding and treatments were conducted for 12 weeks. Treatment with ESGA did not affect gains in the body or fat weight nor increases in fasting glucose, insulin, and HOMA-IR or serum levels of free fatty acids (FFAs), tumor-necrosis factor-α, and interleukin-6 (IL-6). On the contrary, it significantly reduced the serum levels of gamma-glutamyl transpeptidase (GGT), aspartate aminotransferase (AST), alanine aminotransferase (ALT), total triglycerides (TGs), cholesterol (CHOL), and low-density lipoprotein cholesterol (LDL-c) in the HFD-fed rats. In addition, it improved the liver structure, attenuating the increase in fat vacuoles; reduced levels of TGs and CHOL, and the mRNA levels of SREBP1 and acetyl CoA carboxylase (ACC); and upregulated the mRNA levels of proliferator-activated receptor α (PPARα) and carnitine palmitoyltransferase I (CPT I) in HFD-fed rats. These effects were concomitant with increases in the mRNA, cytoplasmic, and nuclear levels of nuclear factor erythroid 2-related factor 2 (Nrf2), glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), and heme oxygenase-1 (HO); a reduction in the nuclear activity of nuclear factor-kappa beta (NF-κB); and inhibition of the activity of nuclear factor kappa B kinase subunit beta (IKKβ). All of these effects were dose-dependent effects in which a normal liver structure and normal levels of all measured parameters were seen in HFD + ESGA (200 mg/kg)-treated rats. In conclusion, ESGA prevents NAFLD in HFD-fed rats by attenuating hyperlipidemia, hepatic steatosis, oxidative stress, and inflammation by acting locally on Nrf2, NF-κB, SREBP1, and PPARα transcription factors.

Western Diet Decreases Hepatic Drug Metabolism in Male LDLr−/−ApoB100/100 Mice

Consumption of a Western diet is an important risk factor for several chronic diseases including nonalcoholic fatty liver disease (NAFLD), but its effect on the xenobiotic metabolizing enzyme activities in the liver has been studied incompletely. In this study, male LDLr−/−ApoB100/100 mice were fed with Western diet (WD) or a standard diet for five months to reveal the effects on drug metabolism such as cytochrome P450 (CYP) oxidation and conjugation activities in the liver. Hepatic steatosis, lobular inflammation, and early fibrosis were observed in WD fed mice, but not in chow diet control mice. When compared to the controls, the WD-fed mice had significantly decreased protein-normalized CYP probe activities of 7-ethoxyresorufinO-deethylation (52%), coumarin 7-hydroxylation (26%), 7-hydroxylation of 3-(3-fluoro-4-hydroxyphenyl)-6-methoxycoumarin (70%), 7-hydroxylation of 3-(4-trifluoromethoxyphenyl)-6-methoxycoumarin (78%), 7-hydroxylation of 3-(3-methoxyphenyl)coumarin (81%), and pentoxyresorufin O-depentylation (66%). Increased activity was seen significantly in sulfonation of 3-(4-methylphenyl)-7-hydroxycoumarin (289%) and cytosol catechol O-methyltranferase (COMT, 148%) in the WD group when compared to the controls. In conclusion, the WD-induced steatosis in male LDLr−/−ApoB100/100 mice was associated with decreased CYP oxidation reactions but had no clear effects on conjugation reactions of glucuronidation, sulfonation, and cytosolic catechol O-methylation. Consequently, the WD may decrease the metabolic elimination of drugs compared to healthier low-fat diets.

A comparative evaluation of propranolol pharmacokinetics in obese versus ideal weight individuals: A blueprint towards a personalised medicine

The pharmacokinetics of propranolol were investigated in obese and healthy weight groups. Research studies in relation to the presented topic were gathered, evaluated, and compared to distinguish variabilities involved amongst different lipophilic drugs and how they impacted the clinical effectiveness. Propranolol is a lipophilic drug so it was predicted that the pharmacokinetics would differ between obese and ideal-weight individuals. Previous research in other lipophilic drugs shows a trend to increase the volume of distribution and half-life in obese compared to ideal weight individuals. However, the majority of both clinical and preclinical studies gathered in this review, found a decrease in the volume of distribution (V_D) and clearance, and minimal significant difference in the half-life, in the obese group when compared with the ideal weight group. Different explanations for this comparison have been theorised including differing tissue blood flow, plasma protein binding, or hepatic clearance in obese compared with ideal weight populations; though the exact reasoning as to why propranolol does not follow the general trend for lipophilic drugs is yet to be determined. These findings regarding propranolol pharmacokinetics can be utilised towards further research and development in personalised medicine for patients with obesity and comorbid cardiovascular disease. The comparative studies highlighted the pharmacokinetic parameters which demonstrated a need for personalised dosage regimes for propranolol and a proposed research direction to understand why the difference exists between these population groups. With the prevalence of obesity continuing to rise, the relative pharmacokinetics of drugs must be evaluated in obese patient groups in order to inform drug dosing regimens and improve current clinical practice.

Comparison of protective effects of hesperetin and pectolinarigenin on high-fat diet-induced hyperlipidemia and hepatic steatosis in Golden Syrian hamsters

A comparative study was conducted to determine whether hesperetin and pectolinarigenin could lower total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL), and high-density lipoprotein cholesterol (HDL) in a high-fat diet (HFD)-induced high lipid model in Golden Syrian hamsters. 48 Golden Syrian hamsters (8 weeks old) were fed with a HFD for 15 days. HFD induced significant increases in plasma TC, TG, LDL, and HDL. Then, these high lipid hamsters were divided into four groups and were administered with 0.5% sodium carboxymethyl cellulose (CMC-Na), hesperetin (100 mg/kg/day), pectolinarigenin (100 mg/kg/day) or atorvastatin (1.0 mg/kg/day), for 7 weeks. It was found that pectolinarigenin treatment resulted in significant reductions in body weight, adiposity index, serum levels of TC, TG and hepatic TC, TG and free fatty acid compared to those in control hamsters with hyperlipidemia (P<0.05). However, hesperetin treatment only caused reductions in plasma TC and hepatic TG levels. Besides, the hamsters treated with pectolinarigenin showed a relatively normal hepatic architecture compared to the hepatic steatosis shown in the control group. Moreover, the expressions of fatty-acid synthase (Fasn) and solute carrier family 27 member 1 (Slc27a1) involved in lipid biosynthesis, were suppressed in the pectolinarigenin-treated groups, and the expression of carnitine palmitoyltransferase 1A (Cpt1a) involved in fatty acid oxidation was increased in the pectolinarigenin-treated group. Taken together, these results suggest pectolinarigenin exerts stronger protective effects against hyperlipidemia and hepatic steatosis than hesperetin, which may involve the inhibition of lipid uptake and biosynthesis.

The Effect of Lipopolysaccharide-Stimulated Adipose-Derived Mesenchymal Stem Cells on NAFLD Treatment in High-Fat Diet-Fed Rats

Background

Nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) are 2 common liver diseases that currently lack effective treatment options.

Objectives

This study aimed to investigate the effect of lipopolysaccharide (LPS)-stimulated adipose-derived stem cells (ADSCs) on NAFLD treatment in an animal model.

Methods

Male Wistar rats were fed a high-fat diet (HFD) to induce NAFLD for 7 weeks. The rats were then categorized into 3 groups: Mesenchymal stem cell (MSC), MSC + LPS, and fenofibrate (FENO) groups. Liver and body weight were measured, and the expression of genes involved in fatty acid biosynthesis, β-oxidation, and inflammatory responses was assessed.

Results

Lipopolysaccharide-stimulated ADSCs were more effective in regulating liver and body weight gain and reducing liver triglyceride (TG) levels compared to the other groups. Treatment with LPS-stimulated ADSCs effectively corrected liver enzymes, including alanine aminotransferase (ALT) and aspartate aminotransferase (AST), and lipid factors, including low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) values, better than treatment with both FENO and MSCs. ADSCs + LPS treatment significantly decreased transforming growth factor β (TGF-β) and genes associated with inflammatory responses. Additionally, there was a significant reduction in reactive oxygen species (ROS) levels in the rats treated with ADSCs + LPS.

Conclusions

Lipopolysaccharide-stimulated ADSCs showed potential in alleviating NAFLD by reducing inflammatory genes and ROS levels in HFD rats, demonstrating better results than treatment with ADSCs and FENO groups alone.

Utility of Human Relevant Preclinical Animal Models in Navigating NAFLD to MAFLD Paradigm

Fatty liver disease is an emerging contributor to disease burden worldwide. The past decades of work established the heterogeneous nature of non-alcoholic fatty liver disease (NAFLD) etiology and systemic contributions to the pathogenesis of the disease. This called for the proposal of a redefinition in 2020 to that of metabolic dysfunction-associated fatty liver disease (MAFLD) to better reflect the current understanding of the disease. To date, several clinical cohort studies comparing NAFLD and MAFLD hint at the relevancy of the new nomenclature in enriching for patients with more severe hepatic injury and extrahepatic comorbidities. However, the underlying systemic pathogenesis is still not fully understood. Preclinical animal models have been imperative in elucidating key biological mechanisms in various contexts, including intrahepatic disease progression, interorgan crosstalk and systemic dysregulation. Furthermore, they are integral in developing novel therapeutics against MAFLD. However, substantial contextual variabilities exist across different models due to the lack of standardization in several aspects. As such, it is crucial to understand the strengths and weaknesses of existing models to better align them to the human condition. In this review, we consolidate the implications arising from the change in nomenclature and summarize MAFLD pathogenesis. Subsequently, we provide an updated evaluation of existing MAFLD preclinical models in alignment with the new definitions and perspectives to improve their translational relevance.

Cytokine modulation by etanercept ameliorates metabolic syndrome and its related complications induced in rats administered a high-fat high-fructose diet

The aim of the present study was to investigate the effect of etanercept (ETA)-an anti-tumor necrosis factor α (TNF-α) monoclonal antibody-on metabolic disorders such as obesity, hypertension, dyslipidemia, and insulin resistance associated with the metabolic syndrome (MS). MS was induced in rats via high-fat high-fructose (HFHF) administration for 8 weeks. Rats were divided into three groups: negative control, HFHF model, and ETA-treated groups [HFHF + ETA (0.8 mg/kg/twice weekly, subcutaneously) administered in the last 4 weeks]. ETA effectively diminished the prominent features of MS via a significant reduction in the percent body weight gain along with the modulation of adipokine levels, resulting in a significant elevation of serum adiponectin consistent with TNF-α and serum leptin level normalization. Moreover, ETA enhanced dyslipidemia and the elevated blood pressure. ETA managed the prominent features of MS and its associated complications via the downregulation of the hepatic inflammatory pathway that induces nonalcoholic steatohepatitis (NASH)-from the expression of Toll-like receptor 4, nuclear factor kappa B, and TNF-α until that of transforming growth factor-in addition to significant improvements in glucose utilization, insulin sensitivity, and liver function parameter activity and histopathological examination. ETA was effective for the treatment of all prominent features of MS and its associated complications, such as type II diabetes mellitus and NASH.

Capparis spinosa improves non-alcoholic steatohepatitis through down-regulating SREBP-1c and a PPARα-independent pathway in high-fat diet-fed rats

Objective

Non-alcoholic steatohepatitis (NASH) has become a global medical problem. Currently, there is no approved pharmacologic treatment for this condition. Previous studies have suggested that in the pathogenesis of this disease, regulatory pathways associated with de novo lipogenesis and β-oxidation pathways genes are misregulated. Capparis spinosa (CS) belongs to the family of Capparidaceae and is a traditional plant used to treat various diseases, particularly dyslipidemia. The compounds and extracts of this plant in In vivo and in vitro studies resulted in a reduction in lipid profiles and glucose. However, the mechanism of these effects remains unknown. This study aimed to evaluate the effects of (CS) fruit extract on NASH compared to fenofibrate and explored the related molecular mechanism.

Results

In the rats (n = 40) model of NASH, biochemical and histopathological examinations showed that liver steatosis, inflammation, and hepatic fibrosis were markedly attenuated in response to CS and fenofibrate interventions. At the molecular level, CS treatment down-regulated sterol regulatory element-binding protein-1c (SREBP-1c) (p < 0.001), acetyl-CoA carboxylase (ACC) (p < 0.001), and up-regulated Carnitine palmitoyltransferase I (CPT1) expression (p < 0.001). In conclusion, CS has favorable therapeutic effects for NASH, which was associated with ameliorating steatosis and fibrosis via regulation of the DNL and β-oxidation pathway genes.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-022-06205-x.

trans-Chalcone inhibits transforming growth factor-β1 and connective tissue growth factor-dependent collagen expression in the heart of high-fat diet-fed rats

Objective: Non-alcoholic fatty liver disease (NAFLD) is one of the main risk factors for cardiovascular mortality and morbidity. This study, for the first time, explored the effects of trans-chalcone on cardiac expressions of myocardial fibrosis-related genes, including transforming growth factor -β1 (TGF-β1), connective tissue growth factor (CTGF/CCN2), and collagen type I.Materials and methods: Twenty-eight rats were randomly divided into four groups: control, received 10% tween 80; chalcone, received trans-chalcone; HFD, received high-fat diet (HFD) and 10% tween 80; HFD + chalcone, received HFD and trans-chalcone, by once-daily gavage for 6 weeks. Finally, cardiac expression levels of TGF-β1, CTGF, and collagen type I were determined.Results: HFD feeding increased mRNA levels of collagen type I, TGF-β1, and CTGF in the heart of rats. However, trans-chalcone inhibited HFD-induced changes.Conclusions: trans-Chalcone can act as a cardioprotective compound by inhibiting TGF-β1 and CTGF-dependent stimulation of collagen type I synthesis in the heart of HFD-fed rats.

Maternal high-fat diet consumption programs male offspring to mitigate complications in liver regeneration

In the last decades, obesity and nonalcoholic fatty liver disease (NAFLD) have become increasingly prevalent in wide world. Fatty liver can be detrimental to liver regeneration (LR) and offspring of obese dams (HFD-O) are susceptible to NAFLD development. Here we evaluated LR capacity in HFD-O after partial hepatectomy (PHx). HFD-O re-exposed or not to HFD in later life were evaluated for metabolic parameters, inflammation, proliferation, tissue repair markers and survival rate after PHx. Increasing adiposity and fatty liver were observed in HFD-O. Despite lower IL-6 levels, Ki67 labeling, cells in S phase and Ciclin D1/PCNA protein content, a lower impact on survival rate was found after PHx, even when re-exposed to HFD. However, no difference was observed between offspring of control dams (SC-O) and HFD-O after surgery. Although LR impairment is dependent of steatosis development, offspring of obese dams are programmed to be protected from the damage promoted by HFD.

H19/let-7 axis mediates caffeine exposure during pregnancy induced adrenal dysfunction and its multi-generation inheritance

Previously, we systemically confirmed that prenatal caffeine exposure (PCE) could cause intrauterine growth retardation (IUGR) and adrenal steroid synthesis dysfunction in offspring rats. However, the multi-generation inheritance of adrenal dysfunction and its epigenetic mechanism has not been reported. In this study, the PCE rat model was established, part of the pregnant rats were executed on gestational day 20, while the others were delivered normally and the fetal rats were reared into adulthood. The PCE female rats of filial generation 1 (F1) were mated with wild males to produce F2 offspring, and the same way to produce F3 offspring. All the adult female rats of three generations were sacrificed for the related detection. Results showed that PCE could decrease fetal weight, increase IUGR rate, and elevate serum corticosterone level. Meanwhile, the expression of fetal adrenal GR, DNMT3a/3b, miRNA let-7c increased while those of CTCF, H19, and StAR decreased, and the total methylation rate of the H19 promoter region was enhanced. We used SW-13 cells to clarify the molecular mechanism and found that cortisol-induced in vitro changes of these indexes were consistent with those in vivo. We confirmed that high level of cortisol through activating GR, on the one hand, promoted let-7 expression and inhibited StAR expression; on the other hand, caused high methylation and low expression of H19 by down-regulating CTCF and up-regulating DNMT3a/3b, then enhanced let-7 inhibitory effect on StAR by "molecular sponge" effect. Finally, in vivo experiments showed that the adrenal steroid synthesis function and H19/let-7 axis presented the glucocorticoid-dependent changes in the adult female F1, F2, and F3. In conclusion, PCE can cause female adrenal dysfunction with matrilineal multi-generation inheritance, which is related to the programming alteration of the H19/let-7 axis. This study provides a novel perspective to explain the multi-generation inheritance of fetal-originated disease in IUGR offspring.

Saroglitazar improved hepatic steatosis and fibrosis by modulating inflammatory cytokines and adiponectin in an animal model of non-alcoholic steatohepatitis

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) have become significant global health concerns. In the present study, we aimed to investigate the effects of saroglitazar, a dual PPARα/γ agonist, fenofibrate, a PPAR-α agonist, and pioglitazone, a PPAR-γ agonist on an animal model of NASH.

METHODS

Male Wistar rats were fed a high-fat (HF) emulsion via gavage for 7 weeks to induce NASH. The HF-treated rats were grouped into four groups to receive saroglitazar, pioglitazone, fenofibrate, or vehicle. We measured body and liver weight, liver enzymes, serum levels of adiponectin and leptin. We also performed histopathological examinations and gene expression analysis of interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF- α), transforming growth factor-beta (TGF-β), and monocyte chemoattractant protein 1 (MCP-1).

RESULTS

Body weight was markedly normalized by both saroglitazar and fenofibrate, while the liver index only decreased significantly with saroglitazar. Saroglitazar corrected ALT, AST, leptin, and adiponectin levels better than pioglitazone and fenofibrate. All PPAR agonists significantly attenuated the upregulation of the proinflammatory and TGF-β genes, which correlated with the improved steatosis, inflammation of liver tissue, and fibrotic lesions.

CONCLUSIONS

As documented by our results, the dual activation of PPARα/γ by saroglitazar could effectively improve steatosis, fibrosis, and aspects of necro-inflammation in the HF-induced NASH model more than fenofibrate and pioglitazone, and it can be more beneficial in the management of NASH.

Anti-inflammatory Effect of Aloe vera Extract on Inflammatory Cytokines of Rats Fed with a High-Fat Diet (HFD)

Background: Cytokines are glycoprotein compounds with an important role in inducing and regulating inflammation. Objectives: The present study aimed to measure the effect of Aloe vera alcoholic extracts on inflammatory cytokines in rats fed with a high-fat diet. Methods: Forty adult male Wistar rats were purchased and randomly categorized into five groups, including two control groups (control and control fed a high-fat diet (HFD) and three experimental groups (high-fat diet + 150 mg/kg Aloe vera, high fat diet + 300 mg/kg Aloe vera, and high-fat diet + 600 mg/kg Aloe vera). The rats in the experimental groups received high-fat emulsion and three doses of Aloe vera for 60 days in the form of gavage. Following blood sampling, serum concentrations of tumor necrosis factor-alpha (TNF-α), transforming growth factor-beta (TGF-β), interleukin 6 (IL-6), and interferon-γ (INF-γ) were measured. Statistical analysis was administered using SPSS-20 software by ANOVA test. Mean comparisons were conducted via Duncan’s multiple range test at the 0.05 level of significance. Results: The findings showed that a high-fat diet (HFD) could increase the concentrations of inflammatory factors TNF-α and TGF-β (P < 0.05). Moreover, an increase in the concentration of inflammatory factor IL-6 was observed at P < 0.01. No significant effects were observed in the mean concentration of INF-γ in the study groups. The use of Aloe vera gel extract considerably reduced inflammatory factors TNF-α, TGF-β, and IL-6 in the Aloe vera extract-receiving groups. Conclusions: In general, the results of the present study revealed that Aloe vera alcoholic extract reduced inflammatory factors in the rats fed with a high-fat diet.

Dimethyl fumarate reduces oxidative stress, inflammation and fat deposition by modulation of Nrf2, SREBP-1c and NF-κB signaling in HFD fed mice

Nonalcoholic fatty liver disease (NAFLD) occurs due to lipid metabolic disorders, which is associated with hepatic oxidative stress and inflammation. There is no definitive drug treatment for this disease. Accordingly, the present study aimed to evaluate the effects of dimethyl fumarate (DMF) as one of the superior effective drugs that induces a transcription factor of nuclear factor erythroid 2-related factor 2 (Nrf2) on development of NAFLD in mice. The metabolic disturbance in High-fat diet (HFD)-treated animals was associated with hyperlipidemia, increased activity levels of hepatic enzymes in serum, hyperglycemia, hyperinsulinemia, oxidative stress and inflammation. DMF supplementation had anti-inflammatory, antioxidant, anti-lipogenic and molecular compatibility effects induced by HFD in mice. In comparison to the HFD group, the DMF therapy could significantly suppress the sterol regulatory element binding protein-1 c (SREBP-1c) gene and protein levels, as well as upregulate the Nrf2 gene and protein levels. Additionally, the anti-inflammatory activity was observed for the DMF by inhibiting the nuclear factor kappa B (NF-κB) level. DMF reduces the development of NAFLD induced by HFD in mice through the modulation of transcription factors Nrf2, SREBP-1c and NF-κB. Thus, DMF can be considered as an effective candidate in the treatment of human NAFLD.

Potential Hepatoprotective Effect of Cheatomorpha gracilis extract against High Fat Diet (HFD)-Induced Liver Damage, and its characterization by HPLC

The current investigation was carried out to estimate the protective effect of aqueous extract of Cheatomorpha gracilis (AEC) against High fat Diet (HFD) induced liver damage in mice. The results of the in vitro study showed that AEC have higher antioxidant capacities in the DPPH and hydroxyl radical-scavenging assays. Indeed, many phenolic compounds (gallic acid, quercetin, naringenin, apigenin, kaempferol and rutin) were identified in the AEC. In the animal studies, during 6 weeks, HFD promoted oxidative stress with a rise level of malonaldehyde (MDA), protein carbonyls (PCOs) levels and a significant decrease of the antioxidant enzyme activities such as superoxide dismutase, catalase and glutathione peroxidase. Interestingly, the treatment with AEC (250 mg/kg body weight) significantly reduced the effects of HFD disorders on some plasmatic liver biomarkers (AST, ALT and ALP) in addition to, plasmatic proteins inflammatory biomarkers (α2 and β1 decreases / β2 and γ globulins increases). It can be suggest that supplementation of MECG displays high potential to quench free radicals and attenuates high fat diet promoted liver oxidative stress and related disturbances.

Moringa peregrina leaf extracts produce anti-obesity, hypoglycemic, anti-hyperlipidemic, and hepatoprotective effects on high-fat diet fed rats

This present research investigated the anti-obesity and hepatoprotective effects of ethanolic Moringa peregrina leaf (MPLE) and bark extracts (MPBE), in the rats fed with a high-fat diet (HFD). Healthy male rats (n = 48) were randomly distributed to six groups (n = 8): control AIN-93 diet; HFD; HFD + MPBE bark extracts ((300 mg/kg); HFD + MPBE (600 mg/kg); HFD + MPLE (300 mg/kg); HFD + MPLE (600 mg/kg). HFD-fed rats in the Moringa peregrina (MP) treatment groups received orally administered MP leaf or bark extract daily for eight weeks. The results revealed that both doses of MP leaf extract significantly reduced HFD-induced increases in their food intake and the gained body weight, fat pad weights (visceral, subcutaneous, and epididymal), glucose and insulin plasma levels, and leptin and resistin serum levels in HFD-fed rats. Concomitantly, MP leaf extract improved glucose levels after oral or intraperitoneal glucose tolerance tests, reduced serum cholesterol, triglycerides, and the low-density lipoprotein LDL concentration, reduced hepatic triglycerides and cholesterol levels, and increased serum high-density lipoproteins HDL levels and triglycerides and cholesterol levels in fecal. Moreover, the administration of MPLE to HFD-fed rats improved liver architecture, reduced fat accumulation, reduced hepatic malondialdehyde, tumor necrosis factor-α, and interleukin-6 levels. Hepatic glutathione peroxidase, superoxide dismutase, and catalase activities were significantly increased. All observed effects were more pronounced in HFD-fed rats treated with a 600 mg/kg MP dose. However, neither dose of MPBE altered the measured markers in the HFD-fed rats. In conclusion, MPLE showed potential anti-obesity and hepatoprotective activity in HFD-induced obese rats, mediated by reduced lipid absorption, anti-hyperlipidemic effects, and hepatic antioxidant effects.

Modeling Diet-Induced NAFLD and NASH in Rats: A Comprehensive Review

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease, characterized by hepatic steatosis without any alcohol abuse. As the prevalence of NAFLD is rapidly increasing worldwide, important research activity is being dedicated to deciphering the underlying molecular mechanisms in order to define new therapeutic targets. To investigate these pathways and validate preclinical study, reliable, simple and reproducible tools are needed. For that purpose, animal models, more precisely, diet-induced NAFLD and nonalcoholic steatohepatitis (NASH) models, were developed to mimic the human disease. In this review, we focus on rat models, especially in the current investigation of the establishment of the dietary model of NAFLD and NASH in this species, compiling the different dietary compositions and their impact on histological outcomes and metabolic injuries, as well as external factors influencing the course of liver pathogenesis.

Maternal exposure to high-fat diet during pregnancy and lactation predisposes normal weight offspring mice to develop hepatic inflammation and insulin resistance

Increasing evidence shows a potential link between the perinatal nutrient environment and metabolic outcome in offspring. Here, we investigated the effects of maternal feeding of a high-fat diet (HFD) during the perinatal period on hepatic metabolism and inflammation in male offspring mice at weaning and in early adulthood. Female C57BL/6 J mice were fed HFD or normal chow (NC) for 4 weeks before mating and during pregnancy and lactation. The male offspring mice were weaned onto an NC diet, and metabolic and molecular experiments were performed in early adulthood. At postnatal day 21, male offspring mice from HFD-fed dams (Off-HFD) showed significant increases in whole body fat mass and fasting levels of glucose, insulin, and cholesterol compared to male offspring mice from NC-fed dams (Off-NC). The RT-qPCR analysis showed two- to fivefold increases in hepatic inflammatory markers (MCP-1, IL-1β, and F4/80) in Off-HFD mice. Hepatic expression of G6Pase and PEPCK was elevated by fivefold in the Off-HFD mice compared to the Off-NC mice. Hepatic expression of GLUT4, IRS-1, and PDK4, as well as lipid metabolic genes, CD36, SREBP1c, and SCD1 were increased in the Off-HFD mice compared to the Off-NC mice. In contrast, CPT1a mRNA levels were reduced by 60% in the Off-HFD mice. At postnatal day 70, despite comparable body weights to the Off-NC mice, Off-HFD mice developed hepatic inflammation with increased expression of MCP-1, CD68, F4/80, and CD36 compared to the Off-NC mice. Despite normal body weight, Off-HFD mice developed insulin resistance with defects in hepatic insulin action and insulin-stimulated glucose uptake in skeletal muscle and brown fat, and these metabolic effects were associated with hepatic inflammation in Off-HFD mice. Our findings indicate hidden, lasting effects of maternal exposure to HFD during pregnancy and lactation on metabolic homeostasis of normal weight offspring mice.

MicroRNA-21 Plays Multiple Oncometabolic Roles in the Process of NAFLD-Related Hepatocellular Carcinoma via PI3K/AKT, TGF-β, and STAT3 Signaling

MicroRNA-21 (miR-21) is one of the most frequently upregulated miRNAs in liver diseases such as nonalcoholic fatty liver disease (NAFLD) and hepatocellular carcinoma (HCC). However, mechanistic pathways that connect NAFLD and HCC remain elusive. We developed a doxycycline (Dox)-inducible transgenic zebrafish model (LmiR21) which exhibited an upregulation of miR-21 in the liver, which in turn induced the full spectrum of NAFLD, including steatosis, inflammation, fibrosis, and HCC, in the LmiR21 fish. Diethylnitrosamine (DEN) treatment led to accelerated liver tumor formation and exacerbated their aggressiveness. Moreover, prolonged miR-21 expression for up to ten months induced nonalcoholic steatohepatitis (NASH)-related HCC (NAHCC). Immunoblotting and immunostaining confirmed the presence of miR-21 regulatory proteins (i.e., PTEN, SMAD7, p-AKT, p-SMAD3, and p-STAT3) in human nonviral HCC tissues and LmiR21 models. Thus, we demonstrated that miR-21 can induce NAHCC via at least three mechanisms: First, the occurrence of hepatic steatosis increases with the decrease of ptenb, pparaa, and activation of the PI3K/AKT pathway; second, miR-21 induces hepatic inflammation (or NASH) through an increase in inflammatory gene expression via STAT3 signaling pathways, and induces liver fibrosis through hepatic stellate cell (HSC) activation and collagen deposition via TGF-β/Smad3/Smad7 signaling pathways; finally, oncogenic activation of Smad3/Stat3 signaling pathways induces HCC. Our LmiR21 models showed similar molecular pathology to the human cancer samples in terms of initiation of lipid metabolism disorder, inflammation, fibrosis and activation of the PI3K/AKT, TGF-β/SMADs and STAT3 (PTS) oncogenic signaling pathways. Our findings indicate that miR-21 plays critical roles in the mechanistic perspectives of NAHCC development via the PTS signaling networks.

Association between metabolic syndrome, hepatic steatosis, and testosterone deficiency: evidences from studies with men and rodents

Testosterone is the predominant androgen in men and the lack of it can be a trigger to the development of the metabolic syndrome. Here we review the relationship between testosterone deficiency, metabolic syndrome, and hepatic steatosis reported by studies with men and rodents. The prevalence of metabolic syndrome and testosterone deficiency is higher among older subjects. Low total and free testosterone levels were positively associated with disturbs on energy metabolism, changes in body fat distribution, and body composition. Studies reported visceral fat accumulation in men with hypogonadism and castrated rats. Despite some contradictions, the association between higher adiposity, low testosterone, and metabolic syndrome was a common point among the studies. Few studies evaluated the hepatic steatosis and found an association with hypogonadism. Most of the studies with rodents combined the castration with a high-fat diet to study metabolic disturbs. The importance of proper levels of testosterone for energy metabolism homeostasis in men was also underlined by studies that investigated the metabolic effects of testosterone replacement therapy and androgen deprivation therapy.

Effects of protocatechuic acid on ameliorating lipid profiles and cardio-protection against coronary artery disease in high fat and fructose diet fed in rats

A coronary heart disease leads to increase in obesity and metabolic dysfunction. Protocatechuic acid (PCA), due to its antioxidant, anti-inflammatory, neuro protective activities was found efficient as cardio-protective in coronary heart disease. Our study investigated hypolipidemic and cardioprotective effects of protocatechuic acid in the coronary artery disease induced by high fat and fructose diet (HFD) rat models. A diet rich in fat and fructose was fed to male Wistar rats prior to the start of experimental procedures. Serum lipid levels and hepatic triglycerides (TG) and total cholesterol (TC) levels were examined and analyzed. Both in vitro an in vivo pancreatic lipase activity was determined as well. Histopathological examination was performed and their results were noted. Noteworthy reduction of serum lipid levels and hepatic TG and TC levels was seen in groups treated with simvastatin (SIM; 20 mg/kg) and PCA (50 and 100 mg/kg) in comparison to HFD groups. Pancreatic lipase activity was reduced in the SIM group and the group treated with doses of PCA (50 and 100 mg/kg). A marked increase in gain in body weight per week (P<0.05) was achieved in HFD group. Coronary risk index (CRI) and Atherogenic index of plasma (AIP) showed decreased index values after treatments with SIM and PCA (50 and 100 mg/kg), respectively. Our findings confirmed the efficacious cardio-protective and hypolipidaemic activities of protocatechuic acid in coronary artery disease induced in rats with fat and fructose rich diet.

trans-Chalcone inhibits high-fat diet-induced disturbances in FXR/SREBP-1c/FAS and FXR/Smad-3 pathways in the kidney of rats

High-fat diet (HFD) intake is linked to chronic kidney disease. Farnesoid X receptor (FXR) controls the renal lipid metabolism and fibrosis. The purpose of the current study was to evaluate the possible impacts of trans-chalcone on HFD-induced changes in renal lipid metabolism and Smad-3 expression through the regulation of FXR expression. To this aim, 28 rats were randomly divided into control, chalcone, HFD, and HFD + chalcone groups. At the end of treatments, renal FXR, sterol regulatory element-binding protein (SREBP)-1c, fatty acid synthase (FAS), Smad-3, and neutrophil gelatinase-associated lipocalin (NGAL) expression levels were assayed. Moreover, insulin sensitivity check index (QUICKI) was calculated. trans-Chalcone significantly inhibited HFD-induced reduction of insulin sensitivity. Moreover, HFD decreased the FXR expression, and trans-chalcone reversed this change. trans-Chalcone also inhibited HFD-induced increases in expression levels of SREBP-1c, FAS, Smad-3, and NGAL. Therefore, trans-chalcone, as a renoprotective agent, inhibits HFD-induced disturbances in FXR/SREBP-1c/FAS and FXR/Smad-3 pathways. PRACTICAL APPLICATIONS: Non-alcoholic fatty liver disease and metabolic syndrome, two health concerns with increasing prevalence, are known as important risk factors for chronic kidney disease. The current study indicated the preventive effect of trans-chalcone administration on HFD-induced disturbances in renal FXR/SREBP-1c/FAS and FXR/Smad-3 pathways. According to these results, trans-chalcone can be regarded as a renoprotective functional food component that can protect individuals with metabolic syndrome against chronic renal disease.

An albino mouse model of nonalcoholic fatty liver disease induced using high-fat liquid "Lieber-DeCarli" diet: a preliminary investigation

Background

Experimental diet models have proven to be vital to understanding the pathophysiology and management of nonalcoholic fatty liver disease (NAFLD). Lieber-DeCarli high-fat, liquid diet have been used to produce NAFLD in rat models. There is, however, currently no information on the effects of this diet in the mouse model.

Methods

Ten (n = 10) male albino mice (27.7 ± 2.0 g) were divided into 2 diet groups (n = 5/group). Animals from group 1 were fed with standard chow diet (CD group) and those from group 2 were fed with Lieber-DeCarli high-fat, liquid diet (high-fat diet or HFD group) ad libitum for a period of 4 weeks.

Results

Data obtained show insulin resistance in the HFD group with a significant increase in plasma lipid profile. Level of cholesterol and triglycerides in the liver and plasma increased significantly (P < .05) in the HFD group compared with the CD group. Plasma level of tumor necrosis factor alpha increased significantly in the HFD group compared to control. Also, indicators of oxidative stress (malondialdehyde and protein carbonyls) increased significantly coupled with a significant reduction in reduced glutathione (GSH) level and activity of glutathione peroxidase in the liver of mice in the HFD group compared to CD group. Histopathological evaluation of liver sections reveals steatosis with ballooned hepatocytes.

Conclusions

Data from the present study suggest that the Lieber-DeCarli high-fat, liquid diet may be vital in the study of fatty liver disease in albino mouse. This model may also produce the features of NAFLD in a shorter time in albino mice.

Capparis spinosa improves the high fat diet-induced non-alcoholic steatohepatitis in rats: the possible role of FGF21

OBJECTIVES

This study focused on the beneficial effects of Capparis spinosa (CS) treatment on the steatohepatitis induced by the administration of a high-fat emulsion in rats. Changes of hepatic expression and secretion of fibroblast growth factor 21 (FGF21) were also evaluated as a probable mechanism of the CS effects on fatty liver. Male Wistar rats were allocated in different groups to receive a normal diet (NC group), a high-fat diet (HF group), or the high-fat emulsion plus CS extract at a dose of 20 mg/kg (HF+CS group). Body and liver weight, liver index, serum biochemical factors, histopathological examination, and serum level and hepatic gene expression of FGF21 were determined.

RESULTS

CS administration markedly reduced liver weight and index, serum levels of glucose, lipids, alanine aminotransferase (ALT), and aspartate aminotransferase (AST) and improved histological features of nonalcoholic steatohepatitis (NASH) which were induced by HF feeding in this model. CS supplementation also restored the decreased hepatic and serum FGF21 levels in the fatty liver rats. We propose that the FGF21 up-regulation may partly account for the favorable effects of CS in this steatohepatitis model.

Lipase Inhibitors for Obesity: A Review

With the rapid increase in the population of obese individuals, obesity has become a global problem. Many kinds of chronic metabolic diseases easily caused by obesity have received increasing attention from researchers. People are also striving to find various safe and effective treatment methods as well as anti-obesity medicines. Pancreatic lipase (PL) inhibitors have received substantial attention from researchers in recent years, and PL inhibitors from natural products have attracted much attention due to their structural diversity, low toxicity and wide range of sources. They have been used in the intestinal tract, blood, and the central nervous system with no side effects, and these advantages could lead to a new generation of diet pills or health care products with great development potential. This article is mainly aimed at discussing the research of obesity drug treatment with PL inhibitors and offers a brief review of related properties and the use of PL inhibitors in the field of weight loss.

Protective Effect of Trans-chalcone Against High-Fat Diet-Induced Pulmonary Inflammation Is Associated with Changes in miR-146a And pro-Inflammatory Cytokines Expression in Male Rats

High-fat diet (HFD) increases the risk of non-communicable inflammatory diseases including pulmonary disorders. Trans-chalcone is a chalcone with antioxidant and anti-inflammatory effects. This study aimed to explore the effect of this natural compound and molecular mechanism of its effect on HFD-induced pulmonary inflammation. Twenty-eight male Wistar rats were randomly divided into four main groups (n = 7 per each group): control, receiving 10% tween 80; Chal, receiving trans-chalcone, HFD, receiving a high-fat emulsion and 10% tween 80; HFD + Chal, receiving a high-fat emulsion and trans-chalcone. After 6 weeks, the lungs were dissected, and the expression levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), and miR-146a were determined using real-time PCR. Moreover, histological analysis was done by hematoxylin and eosin staining. Significant elevations in TNF-α, IL-1β, IL-6, and miR-146a expression levels (P < 0.001) were observed within the lungs of HFD-fed rats compared with the control. However, oral administration of trans-chalcone reduced TNF-α, IL-1β, IL-6 (P < 0.001), and miR-146a (P < 0.05) expression levels and also improved HFD-induced histological abnormalities. These findings indicate that trans-chalcone ameliorates lung inflammatory response and structural alterations. It seems that this beneficial effect is associated with the down-regulation of pro-inflammatory cytokines and miR-146a.

NAFLD Preclinical Models: More than a Handful, Less of a Concern?

Non-alcoholic fatty liver disease (NAFLD) is a spectrum of liver diseases ranging from simple steatosis to non-alcoholic steatohepatitis, fibrosis, cirrhosis, and/or hepatocellular carcinoma. Due to its increasing prevalence, NAFLD is currently a major public health concern. Although a wide variety of preclinical models have contributed to better understanding the pathophysiology of NAFLD, it is not always obvious which model is best suitable for addressing a specific research question. This review provides insights into currently existing models, mainly focusing on murine models, which is of great importance to aid in the identification of novel therapeutic options for human NAFLD.

Structural modulation of gut microbiota during alleviation of non-alcoholic fatty liver disease with Gynostemma pentaphyllum in rats

Background

The current work aimed to assess whether Gynostemma pentaphyllum (GP), a Chinese herbal medicine, structurally modifies the gut microbiota in rats during non-alcoholic fatty liver disease (NAFLD) treatment.

Methods

High-fat diet (HFD)-induced NAFLD rats were orally administered water decoction of GP or equal amounts of distilled water per day for 4 weeks. Liver tissues were examined by histopathological observation, while intestinal tissues were examined by both histopathological and ultrastructural observations. The levels of fasting blood glucose (FBG), fasting serum insulin (FINS), total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), alanine transaminase (ALT) and aspartate transaminase (AST) were measured by enzymatic method. The levels of toll-like receptor 4 (TLR-4), tumor necrosis factor-alpha (TNF-α), interleukin-1-beta (IL-1β) and interleukin-6 (IL-6) in both serum and hepatic tissues were measured by RT-qPCR. The protein expression level of TLR-4 in hepatic tissues was detected by western blot. The gut microbiota was assessed by 16S rRNA-based microbiota analysis.

Results

GP maintained intestinal integrity and reversed gut dysbiosis in high-fat diet (HFD)-induced NAFLD rats. This also reduced the ratio of Firmicutes to Bacteroidetes, enriching the abundance of beneficial bacteria (Lactococcus spp.) and inhibiting the abundance of pathogenic bacteria (Ruminococcus spp.) in the gut. The levels of pro-inflammatory cytokines (TNF-α, IL-1β and IL-6) and the expression of TLR4 were downregulated (P < 0.05), while the insulin resistance index, HOMA-IR showed improvement by GP treatment (P < 0.05). Liver function indicators (ALT and AST) were remarkably decreased (P < 0.01). Besides, GP treatment reduced TG and LDL-C levels (P < 0.05), and increased HDL-C level (P < 0.05) compared with NAFLD group.

Conclusion

The structural alterations of gut microbiota induced by GP are associated with NAFLD alleviation.

Saroglitazar Deactivates the Hepatic LPS/TLR4 Signaling Pathway and Ameliorates Adipocyte Dysfunction in Rats with High-Fat Emulsion/LPS Model-Induced Non-alcoholic Steatohepatitis

The most epidemic liver disorder non-alcoholic steatohepatitis (NASH) is characterized by hepatic steatosis and inflammation with hepatocellular damage. Recently, it is predictable to be the extensive cause for liver transplantation. The absence of an approved therapeutic agent for NASH is the reason for investigating saroglitazar (SAR) which showed promising effects as a dual PPAR-α/γ agonist in recent studies on NASH. Here, we aimed to investigate the effect of SAR on NASH induced in rats by the administration of high-fat emulsion (HFE) and small doses of lipopolysaccharides (LPS) for 5 weeks. Rats were divided into three groups: negative control group (saline and standard rodent chow), model group (HFE(10 ml/kg/day, oral gavage) + LPS(0.5 mg/kg/week, i.p)), and SAR-treated group (HFE(10 ml/kg/day, oral gavage) + LPS(0.5 mg/kg/week, i.p.) + SAR(4 mg/kg/day, oral gavage) starting at week 3.Treatment with SAR successfully ameliorated the damaging effects of HFE with LPS, by counteracting body weight gain and biochemically by normalization of liver function parameters activity, glucose, insulin, homeostasis model of assessment (HOMA-IR) score, lipid profile levels, and histopathological examination. Significant changes in adipokine levels were perceived, resulting in a significant decline in serum leptin and tumor necrosis factor-α (TNF-α) level concurrent with adiponectin normalization. The positive effects observed for SAR on NASH are due to the downregulation of the LPS/TLR4 pathway, as indicated by the suppression of hepatic Toll-like receptor 4 (TLR4), NF-κB, TNF-α, and transforming growth factor-β1 (TGF-β1) expression. In conclusion, this work verified that SAR ameliorates NASH through deactivation of the hepatic LPS/TLR4 pathway and inhibition of adipocyte dysfunction.

A simple method for inducing nonalcoholic steatohepatitis with fibrosis

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is increasingly occurring in sedentary people, and may progress to NASH and hepatocellular carcinoma. It is essential to design affordable animal models for the study of various diseases, including fatty liver, which was the aim of the study. In this study, a high-fat diet was devised that triggers NASH's animal model quickly and easily. High-fat diet (HFD) was used both with intra-mouth oral gavage and in combination with animal pellets.

METHODS

Twenty-four male C57BL/6J mice were divided into HFD and ND groups, which received a high-fat diet and a normal diet, respectively. At the end of the experiment (fourth week of treatment), body and liver weights, biochemical parameters, PPAR-α gene expression and histopathologic characteristics of the liver were evaluated.

RESULTS

During 4 weeks, body weight of mice did not show a significant increase in the HFD group compared to the ND group, while weight gain of the liver was significant. Histological assessment of the HFD group's liver confirmed NASH symptoms. In the HFD group, HDL-c, SOD, catalase, FRAP, adiponectin, and PPAR-α decreased significantly, and lipid profiles, hepatic enzymes, MDA, leptin, and TNF-α showed a significant increase compared to the ND group.

CONCLUSION

Our high-fat diet has successfully induced all aspects of NASH with fibrosis in 4 weeks, and with low cost.

Effects of Isoflavone Supplementation on Lipid Profiles and Antioxidant Enzyme Activities in Growing Rats Fed High Fat Diet

The purpose of this study was to investigate the effects of isoflavone on serum lipids and antioxidant enzymes activities in growing rats fed high lard diet. Twenty four female Sprague-Dawley rats (body weight 50–60 g) were divided into three groups, control, high fat (HF, lard 200 g/kg diet) and high fat + isoflavone (HFI, lard 200 g/kg diet + isoflavone 310.9 mg/kg diet) for 4 weeks. The results of study indicated that body weight gain was not different by isoflavone diet. Mean intake was significantly lower in HF group and HFI group than control group. Food efficiency ratio was significantly higher in HF group and HFI group than control group. The level of serum triglyceride and total cholesterol were significantly lower in HFI group than control group and HF group. The level of high-density lipoprotein cholesterol, was significantly higher in control group than HF group and HFI group. The level of low-density lipoprotein cholesterol was not significantly different by experimental diets, but atherogenic index (AI) was significantly lower in control group and HFI group than HF group. Contents of total cholesterol and triglyceride in liver tissues were found to be insignificant. The concentration of lipid peroxidation, malondialdehyde was significantly lower in control groups and HFI group than HF group. And antioxidant enzymes in liver tissue were not significantly different by lard and isoflavone supplemented diets. In conclusion, it seems possible that isoflavone supplemented high fat diet may produce positive results on level of serum triglyceride, serum total cholesterol, AI and concentration of malondialdyhyde.

The SGLT2 inhibitor dapagliflozin attenuates the activity of ROS-NLRP3 inflammasome axis in steatohepatitis with diabetes mellitus

Background

Diabetes mellitus (DM) is considered as a risk factor for the progress of liver diseases. After tissue damage, there is the highest amplitude of ubiquitously sterile inflammatory response in the liver, resulting in a major clinical consequence concerning a high prevalence of steatohepatitis in DM patients. This study aimed to investigate the inhibitory efficacy of dapagliflozin (DAPA), a sodium glucose cotransporter-2 (SGLT2) inhibitor, on experimental steatohepatitis with DM.

Methods

DM-steatohepatitis model was established by dual intraperitoneal injection of streptozotocin (STZ) and feeding with the high-fat diet (HFD) in apolipoprotein E-deficient (ApoE^-/-) mice (n=40). The mice were concurrently treated with DAPA (1 mg/kg/d) by gavage for 12 weeks.

Results

In ApoE^-/- mice, dual HFD/STZ dramatically induced hepatic damage and inflammation as compared with HFD alone. DAPA treatment was effective to protect from hepatic damage and inflammation in dual HFD/STZ treated ApoE^-/- mice. DAPA also significantly the probability decreased the blood glucose, hepatic lipid accumulation, liver steatosis, and fibrotic response in dual HFD/STZ treated ApoE^-/- mice. Further mechanistic investigations indicated that the protection of DAPA on diabetic liver injury was associated with the suppressed production of hepatic reactive oxygen species (ROS) and malondialdehyde (MDA) and the inhibited activation of NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome.

Conclusions

These data demonstrate the efficacy of DAPA for protecting liver damage, inflammation and steatosis from experimental steatohepatitis with DM, and indicate a possible involvement of the inhibited activity of ROS-NLRP3 inflammasome.

Microarray analysis of apoptosis gene expression in liver injury induced by chronic exposure to arsenic and high-fat diet in male mice

Rapid growth in the incidence of liver disease is largely attributable to lifestyle and environmental contaminants, which are often overlooked as the leading causes of this problem. Thus, the possible contribution of arsenic (As) to high-fat diet (HFD)-induced liver damage was examined via microarray analysis. To perform this experiment, a total number of 40 healthy adult male NMRI mice (22-30 g) were used. To this end, these animals were randomly assigned to four groups of 10. Oxidative stress and histopathological parameters were also evaluated in the liver of the mice exposed to a minimally cytotoxic concentration of As (50 ppm) in drinking water while being fed with a HFD for 20 weeks. Subsequently, apoptosis gene expression profiling was utilized via real-time (RT) PCR array analysis. The results showed that As had increased the amount of HFD-induced liver damage and consequently amplified changes in oxidative stress factors, histopathological parameters, as well as apoptosis pathway genes. Investigating the expression profile of apoptosis pathway genes similarly revealed that caspase-8, as a main upstream contributor to the apoptosis pathway, might play an important role in the induction of apoptosis generated by As and HFD. Ultimately, this study highlighted that As in drinking water could increase sensitivity in mice to HFD-induced liver disease through strengthening apoptosis pathway.

β-ionone inhibits nonalcoholic fatty liver disease and its association with hepatocarcinogenesis in male Wistar rats

Among the primary neoplasias that affect the liver, hepatocellular carcinoma (HCC) is the most frequent and the third leading cause of death related to cancer. Several risk factors predispose individuals to HCC such as nonalcoholic fatty liver disease (NAFLD), whose incidence has significantly increased worldwide. β-ionone (βI) isoprenoid is a known chemopreventive of hepatocarcinogenesis. However, the effects of this compound on NAFLD isolated or in association with hepatocarcinogenesis have not yet been evaluated. A high-fat emulsion administered for 6 weeks resulted in NAFLD in male rats, and oral treatment with βI during this period significantly attenuated its development. Moreover, the presence of NAFLD potentiated hepatocarcinogenesis induced by the resistant hepatocyte (RH) model in these animals by increasing the number and percentage of the liver section area occupied by placental glutathione S-transferase (GST-P)-positive persistent preneoplastic lesions (pPNLs), that are thought to evolve into HCC. This indicates that this NAFLD/RH protocol is suitable for studies of the influence of NAFLD on the HCC development. Therefore, here we also investigated the chemopreventive effect of βI under these two associated conditions. In this context, βI reduced the number and percentage of the liver section area occupied by pPNLs, as well as cell proliferation and the number of oval cells, which are considered potential targets for the development of HCC. Thus, βI presents not only a promising inhibitory effect on NAFLD isolated but also chemopreventive activity when it is associated with hepatocarcinogenesis.

Palmitic Acid-Enriched Diet Induces Hepatic Steatosis and Injury in Adult Zebrafish

Palmitic acid (PA) is the most abundant saturated fatty acid in fast foods and is known to induce inflammation and cellular injury in various tissues. In this study, we investigated whether a PA-enriched diet can induce hepatic steatosis and injury in adult zebrafish. The adult zebrafish exhibited increased body weight, hyperlipidemia, hyperglycemia, and steatosis and a hepatic injury phenotype after being fed with a PA-enriched diet for 6 weeks. The quantitative polymerase chain reaction analysis demonstrated that genes associated with hepatic injury were all significantly increased in the liver. Furthermore, livers from the PA-fed group showed an increased messenger RNA (mRNA) expression associated with oxidative stress and endoplasmic reticulum (ER) stress responses. We also found significant upregulation of genes involved in lipid metabolism and triacylglyceride accumulation. Ultrastructural analysis revealed mitochondrial cristae injury and a dilated ER phenotype in the PA-fed hepatocytes, which can be causes of hepatic injury. PA-enriched diet induced hepatic steatosis and injury in adult zebrafish that recapitulated typical metabolic changes and pathophysiological changes as well as increased oxidative stress and ER stress observed in patients with nonalcoholic fatty liver disease.

Sub-Chronic Microcystin-LR Liver Toxicity in Preexisting Diet-Induced Nonalcoholic Steatohepatitis in Rats

Microcystin-LR (MCLR) is a hepatotoxic cyanotoxin reported to cause a phenotype similar to nonalcoholic steatohepatitis (NASH). NASH is a common progressive liver disease that advances in severity due to exogenous stressors such as poor diet and toxicant exposure. Our objective was to determine how sub-chronic MCLR toxicity affects preexisting diet-induced NASH. Sprague-Dawley rats were fed one of three diets for 10 weeks: control, methionine and choline deficient (MCD), or high fat/high cholesterol (HFHC). After six weeks of diet, animals received vehicle, 10 µg/kg, or 30 µg/kg MCLR via intraperitoneal injection every other day for the final 4 weeks. Incidence and severity scoring of histopathology endpoints suggested that MCLR toxicity drove NASH to a less fatty and more fibrotic state. In general, expression of genes involved in de novo lipogenesis and fatty acid esterification were altered in favor of decreased steatosis. The higher MCLR dose increased expression of genes involved in fibrosis and inflammation in the control and HFHC groups. These data suggest MCLR toxicity in the context of preexisting NASH may drive the liver to a more severe phenotype that resembles burnt-out NASH.

Health Benefits of Carotenoids: A Role of Carotenoids in the Prevention of Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases with a prevalence of ~25% worldwide. NAFLD includes simple hepatic steatosis, non-alcoholic steatohepatitis, fibrosis, and cirrhosis, which can further progress to hepatocellular carcinoma. Therefore, effective strategies for the prevention of NAFLD are needed. The pathogenesis of NAFLD is complicated due to diverse injury insults, such as fat accumulation, oxidative stress, inflammation, lipotoxicity, and apoptosis, which may act synergistically. Studies have shown that carotenoids, a natural group of isoprenoid pigments, prevent the development of NAFLD by exerting antioxidant, lipid-lowering, anti-inflammatory, anti-fibrotic, and insulin-sensitizing properties. This review summarizes the protective action of carotenoids, with primary focuses on astaxanthin, lycopene, β-carotene, β-cryptoxanthin, lutein, fucoxanthin, and crocetin, against the development and progression of NAFLD.

Protective effect and mechanism of Qiwei Tiexie capsule on 3T3-L1 adipocytes cells and rats with nonalcoholic fatty liver disease by regulating LXRα, PPARγ, and NF-κB-iNOS-NO signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Qiwei Tiexie capsule (QWTX) is a representative prescription of Tibetan medicine, which is widely used for long-term treatment of chronic liver disease and nonalcoholic fatty liver disease (NAFLD).

AIM OF THE STUDY

This study explored the effects and mechanism of QWTX on 3T3-L1 adipocytes and NAFLD.

MATERIALS AND METHODS

The 3T3-L1 preadipocytes and NAFLD rat model were used in the study. In 3T3-L1 cells, the cytotoxicity of QWTX was tested by CKK-8, and glucose uptake and fat acid oxidation were assessed by 2-deoxy-D-[³H] glucose and [1-¹⁴C] palmitic acid, respectively. The expression levels of carnitine palmitoyltransferase-1 (CPT-1), liver X receptor α (LXRα), peroxisome proliferator-activated receptor (PPAR) γ, inducible nitric oxide synthase (iNOS), ikappa B α (IκBα), and AKT were determined by PCR and western blot. NAFLD was established by the administration of fat emulsion and sucrose for 9 weeks. The effects of QWTX on lipid metabolism, liver function, and hepatic morphology were observed in NAFLD rats by HE and transmission electron microscope. Serum level of nitric oxide (NO) and fee fatty acid (FFA), superoxide dismutase (SOD) and malondialdehyde (MDA) contents in the liver, as well as the expression levels of Cytochrome P450 2E1 (CYP2E1), NF-κB, monocyte chemoattractant protein 1 (MCP-1), CPT-1, LXRα, PPARα, PPARβ/δ, PPARγ, and iNOS were all detected.

RESULTS

QWTX showed no cell cytotoxicity in 3T3-L1 preadipocyte cells, and increased the ¹⁴CO₂ production rate to 4.15, which indicated the reducing the fatty accumulation. In NAFLD, QWTX attenuated liver steatosis, fat vacuoles and inflammation from the HE staining and electron micrograph tests. For the oxidative stress biomarkers, serum FFA level was reduced and serum NO level was enhanced after QWTX treatment. In liver tissue, SOD was decreased and MDA was significantly increased in NAFLD, and both of them were restored by QWTX. NF-κB and CYP2E1 were also upregulated in NAFLD, while downregulated by QWTX. Downregulation of LXRα, PPARγ and iNOS by QWTX were both observed in the 3T3-L1 adipocytes and NAFLD model.

CONCLUSIONS

QWTX protected the liver injury in differentiated 3T3-L1 adipocytes and NAFLD by regulating the LXRα, PPARγ, and NF-κB-iNOS-NO signal pathways.

Inhibiting Extracellular Cathepsin D Reduces Hepatic Steatosis in Sprague⁻Dawley Rats †

Dietary and lifestyle changes are leading to an increased occurrence of non-alcoholic fatty liver disease (NAFLD). Using a hyperlipidemic murine model for non-alcoholic steatohepatitis (NASH), we have previously demonstrated that the lysosomal protease cathepsin D (CTSD) is involved with lipid dysregulation and inflammation. However, despite identifying CTSD as a major player in NAFLD pathogenesis, the specific role of extracellular CTSD in NAFLD has not yet been investigated. Given that inhibition of intracellular CTSD is highly unfavorable due to its fundamental physiological function, we here investigated the impact of a highly specific and potent small-molecule inhibitor of extracellular CTSD (CTD-002) in the context of NAFLD. Treatment of bone marrow-derived macrophages with CTD-002, and incubation of hepatic HepG2 cells with a conditioned medium derived from CTD-002-treated macrophages, resulted in reduced levels of inflammation and improved cholesterol metabolism. Treatment with CTD-002 improved hepatic steatosis in high fat diet-fed rats. Additionally, plasma levels of insulin and hepatic transaminases were significantly reduced upon CTD-002 administration. Collectively, our findings demonstrate for the first time that modulation of extracellular CTSD can serve as a novel therapeutic modality for NAFLD.

Nonalcoholic fatty liver disease alters microcystin-LR toxicokinetics and acute toxicity

Microcystin-LR (MCLR) is a cyanotoxin produced by blue-green algae that causes liver and kidney toxicities. MCLR toxicity is dependent on cellular uptake through the organic anion transporting polypeptide (OATP) transporters. Nonalcoholic fatty liver disease (NAFLD) progresses through multiple stages, alters expression of hepatic OATPs, and is associated with chronic kidney disease. The purpose of this study was to determine whether NAFLD increases systemic exposure to MCLR and influences acute liver and kidney toxicities. Rats were fed a control diet or two dietary models of NAFLD; methionine and choline deficient (MCD) or high fat/high cholesterol (HFHC). Two studies were performed in these groups: 1) a single dose intravenous toxicokinetic study (20 μg/kg), and 2) a single dose intraperitoneal toxicity study (60 μg/kg). Compared to control rats, plasma MCLR area under the concentration-time curve (AUC) in MCD rats doubled, whereas biliary clearance (Clbil) was unchanged; in contrast, plasma AUC in HFHC rats was unchanged, whereas Clbil approximately doubled. Less MCLR bound to PP2A was observed in the liver of MCD rats. This shift in exposure decreased the severity of liver pathology only in the MCD rats after a single toxic dose of MCLR (60 μg/kg). In contrast, the single toxic dose of MCLR increased hepatic inflammation, plasma cholesterol, proteinuria, and urinary KIM1 in HFHC rats more than MCLR exposed control rats. In conclusion, rodent models of NAFLD alter MCLR toxicokinetics and acute toxicity and may have implications for liver and kidney pathologies in NAFLD patients.

Glucocorticoid-activation system mediated glucocorticoid-insulin-like growth factor 1 (GC-IGF1) axis programming alteration of adrenal dysfunction induced by prenatal caffeine exposure

Glucocorticoids play a major factor in fetal maturation and fate decision after birth. We have previously demonstrated that prenatal caffeine exposure (PCE) resulted in adrenal dysplasia. However, its molecular mechanism has not been clarified. In the present study, a rat model of intrauterine growth retardation (IUGR) was established by PCE, and offspring were sacrificed. Moreover, NCI-H295 A cells were used to confirm glucocorticoid-related molecular mechanism. Results showed that PCE fetal weight decreased, and the IUGR rate increased, while serum corticosterone levels increased but insulin-like growth factor 1 (IGF1) levels decreased. Fetal adrenals exhibited an activated glucocorticoid-activation system, and the downregulated expression of IGF1 signal pathway and steroidal synthetases. For adult rats, there was no significant change in the glucocorticoid-activation system in the PCE group, the IGF1 signal pathway showed increased trend, and the expression levels of adrenal steroidal synthetases were close to normal. The data in vitro showed that the cortisol of 1200 nM can inhibit the expression of adrenocortical cell steroidal synthetases and IGF1 signal pathway when compared with the control. Meanwhile, the glucocorticoid-activation system was activated while GR inhibitor mifepristone can reverse the effect of cortisol. Furthermore, cortisol can also promote GR into the nucleus after its activation. Based on these findings, we speculated that high concentrations of glucocorticoid in utero led to GR in the nucleus through its activation and then inhibited the IGF1 signaling pathway by activating the glucocorticoid-activation system, which could further downregulate steroid synthesis.

Preventive effect of trans-chalcone on non-alcoholic steatohepatitis: Improvement of hepatic lipid metabolism

Non-alcoholic steatohepatitis (NASH) is an inflammatory and progressive form of non-alcoholic fatty liver disease. However, there are no FDA-approved drugs for this condition. Lipids accumulated in NASH have a direct role in the progression of this disease. Therefore, this study for the first time explored the preventive effect of trans-chalcone on NASH through the modulation of sterol regulatory element binding protein (SREBP)-1c, SREBP-2, hepatic fatty acid synthesis (FAS) enzyme, proliferator-activated receptor (PPAR)-α, and PPAR-γ2 levels, which are involved in hepatic lipid metabolism. In this study, male rats were randomly divided into three groups (n = 7): Control, received 10% tween 80; NASH, received 10% tween 80 and 10 ml/kg high-fat emulsion (high-fat diet, HFD); and NASH + TC, received 20 mg/kg trans-chalcone and 10 ml/kg HFD. All treatments were performed by once-daily oral gavage for 6 weeks. Liver and blood samples were collected and serum levels of alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), triglyceride, total cholesterol, low-density lipoprotein (LDL)-cholesterol, and high-density lipoprotein (HDL)-cholesterol, as well as hepatic levels of SREBP-1c, SREBP-2, FAS, PPAR-α, and PPAR-γ2, were measured. Moreover, hematoxylin and eosin stained tissues were used for histological analysis. In this study, treatment of HFD-fed rats with trans-chalcone significantly reduced abnormalities in liver histology, serum levels of liver injury markers, liver index, and hepatic levels of SREBP-1c, SREBP-2, FAS, and PPAR-γ2. Furthermore, trans-chalcone significantly increased hepatic PPARα levels in these rats. Therefore, it seems that trans-chalcone protects the liver of HFD-fed rats against NASH development through reduction of SREBP-1c/ FAS- and PPAR-γ2-related lipogenesis, attenuation of SREBP-2-related cholesterol synthesis, and elevation of PPARα-related fatty acid oxidation.

Relationship between Experimental Diet in Rats and Nonalcoholic Hepatic Disease: Review of Literature

BACKGROUND

The pathophysiology of nonalcoholic fatty liver disease (NAFLD) is related to unhealthy lifestyles that combine sedentary lifestyle, hypercaloric diets, excessive saturated fats, refined carbohydrates, and high intake of fructose as a food additive to various processed products. Both the broader recognition of the disease and the additional efforts to elucidate the NAFLD pathogenesis have led to an increase in animal models in recent years. Objective. This review was performed to provide better understanding of the association between the NAFLD and animal models.

METHODS

The search in the literature occurred before May of 2018 in the PUBMED database.

RESULTS

Most studies investigating the influence of diet on liver fat content have been performed using a high-calorie diet that leads to a significant increase in fat content in the liver.

CONCLUSION

The findings of this review show that diet is one of the factors that predisposes to the appearance of NAFLD and that the studies presented a wide variety of designs.

Voluntary alcohol consumption exacerbated high fat diet-induced cognitive deficits by NF-κB-calpain dependent apoptotic cell death in rat hippocampus: Ameliorative effect of melatonin

Modern sedentary lifestyle with altered dietary habits imposes the risk of human health towards several metabolic disorders such as obesity. The metabolic insults negatively affect the mental health status and quality life of affected individuals. Melatonin is a potent antioxidant with anti-inflammatory and neuroprotective properties. The aim of the present study was to investigate the protective effect of melatonin on the cognitive and neurochemical deficits induced by the high-fat diet (HFD) and alcohol (ALC) alone or in combination (HFD + ALC) in rats. Male Wistar rats were given ALC (3-15% i.e. increased gradually) and HFD for 12 weeks in different experimental groups. After 12 weeks, we found that simultaneous consumption of HFD and ALC exacerbates cognitive dysfunction and neurochemical anomalies. However, melatonin (10 mg/kg/day, i.p.) treatment for four weeks significantly prevented memory deficits, oxidative stress and neuroinflammation in HFD, ALC and HFD + ALC groups. RT-PCR analysis showed down-regulation of nuclear factor erythroid 2-related factor 2 (Nrf-2) and heme oxygenase-1 (HO-1) in ALC and HFD + ALC groups. Moreover, caspase-3 and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) mRNA expression level were found up-regulated in hippocampus of HFD, ALC and HFD + ALC groups. However, calpain expression was found up-regulated only in the hippocampus of HFD + ALC group. Chronic treatment with melatonin significantly restored the aberrant gene expression level in HFD, ALC and HFD + ALC group. In conclusion, our findings indicated that melatonin can mitigate the HFD and ALC-induced cognitive deficits via attenuation of oxidative stress and calpain-1 dependent as well as independent caspase-3 mediated neuronal cell death.