Deletion of p38γ attenuates ethanol consumption- and acetaminophen-induced liver injury in mice through promoting Dlg1

Alcohol Plus Additional Risk Factors: Rodent Model of Liver Injury

Alcohol-associated liver disease (ALD), primarily caused by chronic excessive alcohol consumption, is a leading cause of chronic liver disease worldwide. ALD includes alcohol-associated steatotic liver, alcohol-associated hepatitis (AH), fibrosis, cirrhosis, and can even progress to hepatocellular carcinoma (HCC). Existing research indicates that the risk factors of ALD are quite numerous. In addition to drinking patterns, factors such as aldehyde dehydrogenase 2 (ALDH2) deficiency, smoking, medication administration, high-fat diet (HFD), hepatitis virus infection, and disruption of circadian rhythms can also increase susceptibility to ALD. However, there is limited understanding regarding the exacerbation of liver injury by alcohol plus additional risk factors. This review presents rodent models of EtOH + "X," which simulate the synergistic effects of alcohol and additional risk factors in causing liver injury. These models offer a further exploration of the interactions between alcohol and additional risk factors, advancing the simulation of human ALD and providing a more reliable platform for studying disease mechanisms and exploring therapeutic interventions. We summarize the modeling methods, relevant indicators of liver injury, and focus on the targets of the synergistic effects as well as the associated mechanisms.

Modulation of Paracetamol-Induced Hepatotoxicity by Acute and Chronic Ethanol Consumption in Mice: A Study Pilot

Paracetamol (APAP) overdose is the leading cause of drug-induced liver injury, leading to acute liver failure. However, the role of concurrent acute or chronic ethanol ingestion in this context requires further clarification. In this study, we investigated the effects of acute and chronic ethanol ingestion on APAP-induced hepatotoxicity. Male C57BL/6 mice were randomly allocated into four groups: control (C; water 2×/day for 7 days); APAP (single dose of APAP, 500 mg/kg); acute ethanol (AE; a single ethanol dose-10 mL/kg, and one hour later an overdose of APAP-500 mg/kg); chronic ethanol (CE; ethanol-10 mL/kg, 2×/day for 7 days; and on the last day, an overdose of APAP-500 mg/kg). The results showed that AE induced heightened liver damage, increased necrotic area, and elevated levels of ALT, AST, TBARS, and oxidized glutathione compared to the control group. The AE group exhibited diminished glutathione availability and elevated CYP2E1 levels compared to the other groups. CE maintained a hepatic profile similar to that of the control group in terms of necrosis index, ALT and AST levels, GSH/GSSG ratio, and CYP2E1 activity, along with the upregulation of gene expression of the glucuronidation enzyme compared to the APAP group. Proteomic analysis revealed that the AE protein profile closely resembled that of the APAP group, whereas the C and CE groups were clustered together. In conclusion, ethanol consumption differentially modulated APAP overdose-induced liver damage. Acute consumption exacerbated hepatotoxicity, similar to an APAP overdose alone, whereas chronic consumption appeared to mitigate this injury, at least within the parameters assessed in this study.

Studies on the Changes of Fermentation Metabolites and the Protective Effect of Fermented Edible Grass on Stress Injury Induced by Acetaminophen in HepG2 Cells

In this study, gas chromatography-mass spectrometry (GC-MS) based untargeted metabolomics was used to describe the changes of metabolites in edible grass with Lactobacillus plantarum (Lp) fermentation durations of 0 and 7 days, and subsequently to investigate the protective effect of fermented edible grass on acetaminophen-induced stress injury in HepG2 cells. Results showed that 53 differential metabolites were identified, including 31 significantly increased and 22 significantly decreased metabolites in fermented edible grass. Fermented edible grass protected HepG2 cells against acetaminophen-induced stress injury, which profited from the reduction in lactate dehydrogenase (LDH) and malondialdehyde (MDA) levels and the enhancement in superoxide dismutase (SOD) activity. Cell metabolomics analysis revealed that a total of 13 intracellular and 20 extracellular differential metabolites were detected. Fermented edible grass could regulate multiple cell metabolic pathways to exhibit protective effects on HepG2 cells. These findings provided theoretical guidance for the formation and regulation of bioactive metabolites in fermented edible grass and preliminarily confirmed the protective effects of fermented edible grass on drug-induced liver damage.

Experimental In Vivo Toxicity Models for Alcohol Toxicity

Alcohol consumption poses a significant risk for the development of chronic illnesses, one of the leading causes of "preventable" disease and death worldwide. Harmful consumption of alcohol is thought to result in approximately 2.5-3 million deaths each year, the majority of which are caused by alcohol-related liver diseases. Hepatocellular carcinoma, cirrhosis, fibrosis, steatosis, and steatohepatitis are among the liver illnesses caused by alcohol. The mechanisms behind human diseases are often mimicked and understood through the use of animal models. Rodents are the ideal animals to study alcohol-related liver diseases. In these experimental models using rodents, the ethanol ratio, method of administration, and diet to be applied vary. Within the scope of this review, it is aimed at providing information about the experimental models used today for alcohol toxicity and the advantages and disadvantages of these models.

Puerarin inhibits inflammation and lipid accumulation in alcoholic liver disease through regulating MMP8

Alcoholic liver disease (ALD) is a growing global health concern, and its early pathogenesis includes steatosis and steatohepatitis. Inhibiting lipid accumulation and inflammation is a crucial step in relieving ALD. Evidence shows that puerarin (Pue), an isoflavone isolated from Pueraria lobata, exerts cardio-protective, neuroprotective, anti-inflammatory, antioxidant activities. However, the therapeutic potential of Pue on ALD remains unknown. In the study, both the NIAAA model and ethanol (EtOH)-induced AML-12 cell were used to explore the protective effect of Pue on alcoholic liver injury in vivo and in vitro and related mechanism. The results showed that Pue (100 mg·kg-1) attenuated EtOH-induced liver injury and inhibited the levels of SREBP-1c, TNF-α, IL-6 and IL-1β, compared with silymarin (Sil, 100 mg·kg-1). In vitro results were consistent within vivo results. Mechanistically, Pue might suppress liver lipid accumulation and inflammation by regulating MMP8. In conclusion, Pue might be a promising clinical candidate for ALD treatment.

Label-Free Imaging Techniques to Evaluate Metabolic Changes Caused by Toxic Liver Injury in PCLS

Abuse with hepatotoxic agents is a major cause of acute liver failure. The search for new criteria indicating the acute or chronic pathological processes is still a challenging issue that requires the selection of effective tools and research models. Multiphoton microscopy with second harmonic generation (SHG) and fluorescence lifetime imaging microscopy (FLIM) are modern label-free methods of optical biomedical imaging for assessing the metabolic state of hepatocytes, therefore reflecting the functional state of the liver tissue. The aim of this work was to identify characteristic changes in the metabolic state of hepatocytes in precision-cut liver slices (PCLSs) under toxic damage by some of the most common toxins: ethanol, carbon tetrachloride (CCl4) and acetaminophen (APAP), commonly known as paracetamol. We have determined characteristic optical criteria for toxic liver damage, and these turn out to be specific for each toxic agent, reflecting the underlying pathological mechanisms of toxicity. The results obtained are consistent with standard methods of molecular and morphological analysis. Thus, our approach, based on optical biomedical imaging, is effective for intravital monitoring of the state of liver tissue in the case of toxic damage or even in cases of acute liver injury.

Salvianolic Acid A Protects against Acetaminophen-Induced Hepatotoxicity via Regulation of the miR-485-3p/SIRT1 Pathway

The vast majority of drug-induced liver injury is mainly attributed to acetaminophen (APAP) overdose. Salvianolic acid A (Sal A), a powerful water-soluble compound obtained from Salvia miltiorrhiza, has been confirmed to exert hepatoprotective effects. However, the beneficial effects and the exact mechanisms of Sal A on APAP-induced hepatotoxicity remain unclear. In this study, APAP-induced liver injury with or without Sal A treatment was examined in vitro and in vivo. The results showed that Sal A could alleviate oxidative stress and inflammation by regulating Sirtuin 1 (SIRT1). Furthermore, miR-485-3p could target SIRT1 after APAP hepatotoxicity and was regulated by Sal A. Importantly, inhibiting miR-485-3p had a hepatoprotective effect similar to that of Sal A on APAP-exposed AML12 cells. These findings suggest that regulating the miR-485-3p/SIRT1 pathway can alleviate oxidative stress and inflammation induced by APAP in the context of Sal A treatment.

P38γ modulates the lipid metabolism in non-alcoholic fatty liver disease by regulating the JAK-STAT signaling pathway

Non-alcoholic fatty liver disease (NAFLD) is a major health problem in Western countries and has become the most common cause of chronic liver disease. Although NAFLD is closely associated with obesity, inflammation, and insulin resistance, its pathogenesis remains unclear. The disease begins with excessive accumulation of triglycerides in the liver, which in turn leads to liver cell damage, steatosis, inflammation, and so on. P38γ is one of the four isoforms of P38 mitogen-activated protein kinases (P38 MAPKs) that contributes to inflammation in different diseases. In this research, we investigated the role of P38γ in NAFLD. In vivo, a NAFLD model was established by feeding C57BL/6J mice with a methionine- and choline-deficient (MCD) diet and adeno-associated virus (AAV9-shRNA-P38γ) was injected into C57BL/6J mice by tail vein for knockdown P38γ. The results indicated that the expression level of P38γ was upregulated in MCD-fed mice. Furthermore, the downregulation of P38γ significantly attenuated liver injury and lipid accumulation in mice. In vitro, mouse hepatocytes AML-12 were treated with free fatty acid (FFA). We found that P38γ was obviously increased in FFA-treated AML-12 cells, whereas knockdown of P38γ significantly suppressed lipid accumulation in FFA-treated AML-12 cells. Furthermore, P38γ regulated the Janus Kinase-Signal transducers and activators of transcription (JAK-STAT) signaling pathway. Inhibition of P38γ can inhibit the JAK-STAT signaling pathway, thereby inhibiting lipid accumulation in FFA-treated AML-12 cells. In conclusion, our results suggest that targeting P38γ contributes to the suppression of lipid accumulation in fatty liver disease.

Advancements in the Alcohol-Associated Liver Disease Model

Alcohol-associated liver disease (ALD) is an intricate disease that results in a broad spectrum of liver damage. The presentation of ALD can include simple steatosis, steatohepatitis, liver fibrosis, cirrhosis, and even hepatocellular carcinoma (HCC). Effective prevention and treatment strategies are urgently required for ALD patients. In previous decades, numerous rodent models were established to investigate the mechanisms of alcohol-associated liver disease and explore therapeutic targets. This review provides a summary of the latest developments in rodent models, including those that involve EtOH administration, which will help us to understand the characteristics and causes of ALD at different stages. In addition, we discuss the pathogenesis of ALD and summarize the existing in vitro models. We analyse the pros and cons of these models and their translational relevance and summarize the insights that have been gained regarding the mechanisms of alcoholic liver injury.