Acetaminophen-induced Hepatotoxicity In Mice Research Articles

Effects of gossypin on acetaminophen-induced hepatotoxicity in mice

Liver injury from paracetamol (acetaminophen) (APAP) is common worldwide. To prevent intoxication with a drug with high poisoning, treatment can be made possible with an easily accessible and harmless substance. This study aimed to investigate the hepatoprotective ef-fects of Gossypin (GOS) in mice exposed to an overdose of APAP -the possible mechanism of action. Specifically, serum [alanine aminotransferase (ALT), aspartate transaminase (AST), and hepatic biochemical parameters (glutathione (GSH), malondialdehyde (MDA) and super-oxide dismutase (SOD)] were evaluated. Protein and mRNA levels of inflammatory, apoptot-ic, and cytochrome factors, including TNF-α, IL-1β, IL-6, NF-kB, and CYP2E1, were ana-lyzed using real-time PCR. Pretreatment with GOS significantly reduced APAP-induced he-patic injury via oxidative stress. Along with potent antioxidant activity, GOS promoted APAP hepatic detoxification by regulating AST, ALT, GSH, MDA, and SOD activities and mRNA levels of the cytochrome CYP2E1 gene. The anti-inflammatory activity of GOS in-creases its production. TNF-α, IL-1β and IL-6, through possible NF-kB blockade, are also responsible for its hepatoprotective effect. Taken together, GOS has the potential to be devel-oped as a preventive agent to be administered to patients suffering from APAP overdose.

Hepatoprotective effects of Elaeagnus latifolia fruit extract against acetaminophen-induced hepatotoxicity in mice: Mechanistic insights

Elaeagnus latifolia fruit extract (EE) has been reported to contain antioxidant and anti-inflammatory phytochemicals. The present study aimed to examine the anti-hepatotoxic effects of EE in acetaminophen (APAP)-injected mice. Pretreatment with EE for 7 days in APAP mice showed significant reductions in the levels of AST and ALT and necrotic area, accompanied by decreases in liver oxidative stress, nitric oxide, and infiltrating inflammatory cells, compared to the APAP-only group. EE markedly down-regulated expression of CYP2E1, JNK, Bax, NOX subunit, and NF-κB target genes, and up-regulated expression of Bcl-2 and Nrf2 target genes in the livers. Furthermore, EE effectively lowered serum and hepatic lipids, and down-regulated expression of SREBP-1c/2 genes. EE was found to contain phenolic compounds, flavonoids, and proanthocyanidins. Therefore, mechanistic insights into EE's anti-hepatotoxic effects may be associated with preventing the abnormal expression of genes involved in toxic metabolite generation, hepatotoxic signaling, apoptosis, oxidative stress, inflammation, and lipid synthesis.

Jujuboside B alleviates acetaminophen-induced hepatotoxicity in mice by regulating Nrf2-STING signaling pathway

BackgroundJujuboside B (JuB) is the main bioactive saponin component of Chinese anti-insomnia herbal medicine Ziziphi Spinosae Semen, which has been reported to possess varied pharmacological functions. Even though it has been traditionally used to treat inflammation- and toxicity-related diseases, the effects of JuB on acetaminophen (APAP) overdose-induced hepatotoxicity have not been determined yet. MethodsC57BL/6 J mice were pre-treated with JuB (20 or 40 mg/kg) for seven days before APAP (400 mg/kg) injection. After 24 h of APAP treatment, serum, and liver tissues were collected to evaluate the therapeutic effects. To investigate whether the Nrf2-STING signaling pathway is involved in the protective effects of JuB against APAP-induced hepatotoxicity, the mice received the DMXAA (the specific STING agonist) or ML385 (the specific Nrf2 inhibitor) during the administration of JuB, and Hematoxylin-eosin staining, Real-time PCR, immunohistochemical, and western blot were performed. ResultsJuB pretreatment reversed APAP-induced CYP2E1 accumulations and alleviated APAP-induced acute liver injury. Furthermore, JuB treatment significantly inhibited oxidative stress and the pro-inflammatory cytokines, as well as alleviated hepatocyte apoptosis induced by APAP. Besides, our result also demonstrated that JuB treatment upregulated the levels of total Nrf2, facilitated its nuclear translocation, upregulated the expression of HO-1 and NQO-1, and inhibited the APAP-induced STING pathway activation. Finally, we verified that the beneficial effects of JuB were weakened by DMXAA and ML385. ConclusionOur study suggested that JuB could ameliorate APAP-induced hepatic damage and verified a previously unrecognized mechanism by which JuB prevented APAP-induced hepatotoxicity through adjusting the Nrf2-STING pathway.

Evaluation the anti-inflammatory effect of Omega 369 against acetaminophen-induced hepatotoxicity in mice

Background: Acetaminophen (N-acetyl-para-aminophenol, or APAP) poisoning, whether intentional or accidental, is a major general health problem, with its toxicity prevalence significantly increasing in many countries. Currently, acetaminophen is considered one of the main causes of acute liver failure globally.Aim: The aim of this study was to evaluate the possible hepatoprotective effect of Omega-3,6,9 against acetaminophen-induced hepatotoxicity in albino male mice.Methods: Thirty-five albino male mice were randomly divided into five groups: Group 1 (the negative control) received liquid paraffin orally at a dose of 10 ml/kg for ten days, followed by a single intraperitoneal injection (IP) of 10 ml/kg normal saline on the eleventh day of the test. Group 2 (positive control) received liquid paraffin. Group 3 was treated with Omega-3,6,9 (50 mg/kg/80 mL). Group 4 was treated with Omega-3,6,9 (100 mg/kg/35 mL). Group 5 was treated with N-acetylcysteine (100 mg/kg/10 ml). The mice were treated with Omega-3,6,9, N-acetylcysteine, and liquid paraffin once daily by oral gavage for ten days.Result: TNF-α, IL-10, ALT, and AST levels in the positive control group were significantly higher than those in the negative control group. TNF-α, IL-10, ALT, and AST levels in mice given Omega-3,6,9 (50 mg/kg), Omega-3,6,9 (100 mg/kg), and N-acetylcysteine (100 mg/kg) orally prior to acetaminophen injection were significantly decreased compared to those in the positive control group.Conclusion: Oral intake of Omega-3,6,9 may reduce the risk of acetaminophen-induced liver damage.

Calcitriol Protects against Acetaminophen-Induced Hepatotoxicity in Mice.

Acetaminophen (APAP) overdose is one of the major causes of acute liver failure. Severe liver inflammation and the production of oxidative stress occur due to toxic APAP metabolites and glutathione depletion. Growing evidence has proved that vitamin D (VD) exerts anti-inflammatory and antioxidative functions. Our objective was to explore the protective role of calcitriol (VD3) in acute APAP-induced liver injury. Methods: Adult male mice were randomized into three groups; control (n = 8), APAP (n = 8), and VD3 group (n = 8). All mice, except controls, received oral administration of APAP (400 mg/kg) and were sacrificed 24 h later. In the VD3 group, calcitriol (10 µg/kg) was injected intraperitoneally 24 h before and after exposure to APAP. Blood samples were collected to assess serum aminotransferase and inflammatory cytokines [tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6)]. Liver tissues were analyzed for hepatic glutathione (GSH), malondialdehyde (MDA), and histopathology. Results: APAP administration significantly increased serum aminotransferase, inflammatory cytokines, and induced cellular inflammation and necrosis. APAP also depleted hepatic GSH and elevated oxidative stress, as indicated by high MDA levels. In the APAP group, 25% of the mice (two out of eight) died, while no deaths occurred in the VD3 group. Treatment with calcitriol significantly reduced serum aminotransferase, TNF-α, and IL-6 levels in the VD3 group compared to the APAP group. Additionally, VD3 effectively restored GSH reserves, reduced lipid peroxidation, and attenuated hepatotoxicity. Conclusions: These findings demonstrate that VD3 prevents APAP-induced acute liver injury and reduces mortality in mice through its anti-inflammatory and antioxidative activity. Thus, VD3 might be a novel treatment strategy for APAP-induced hepatotoxicity.

Protective Effects of Apamin on Acetaminophen-Induced Hepatotoxicity in Mice

Acetaminophen (APAP) overdose can cause severe liver damage, but therapeutic options are limited. Apamin is a natural peptide present in bee venom and has antioxidant and anti-inflammatory properties. Accumulating evidence suggests that apamin has favorable actions in rodent models of inflammatory disorders. Here, we examined the effect of apamin on APAP-evoked hepatotoxicity. Intraperitoneal administration of apamin (0.1 mg/kg) alleviated histological abnormalities and reduced serum levels of liver enzymes in mice injected with APAP. Apamin inhibited oxidative stress through an increase in the amount of glutathione and activation of the antioxidant system. Apamin also attenuated apoptosis with inhibition of caspase-3 activation. Moreover, apamin reduced serum and hepatic levels of cytokines in APAP-injected mice. These effects were accompanied by suppression of NF-κB activation. Furthermore, apamin inhibited chemokine expression and inflammatory cell infiltration. Our results suggest that apamin dampens APAP-evoked hepatotoxicity through inhibiting oxidative stress, apoptosis, and inflammation.

Loss of microRNA-21 protects against acetaminophen-induced hepatotoxicity in mice.

Acetaminophen (APAP)-induced Acute Liver Failure (ALF) is recognized as the most common cause of ALF in Western societies. APAP-induced ALF is characterized by coagulopathy, hepatic encephalopathy, multi-organ failure, and death. MicroRNAs are small, non-coding RNAs that regulate gene expression at the post-transcriptional level. MicroRNA-21 (miR-21) is dynamically expressed in the liver and is involved in the pathophysiology of both acute and chronic liver injury models. We hypothesize that miR-21genetic ablation attenuates hepatotoxicity following acetaminophen intoxication. Eight-week old miR-21knockout (miR21KO) or wild-type (WT) C57BL/6N male mice were injected with acetaminophen (APAP, 300mg/kg BW) or saline. Mice were sacrificed 6 or 24h post-injection. MiR21KO mice presented attenuation of liver enzymes ALT, AST, LDH compared with WT mice 24h post-APAP treatment. Moreover, miR21KO mice had decreased hepatic DNA fragmentation and necrosis than WT mice after 24h of APAP treatment. APAP-treated miR21KO mice showed increased levels of cell cycle regulators CYCLIN D1 and PCNA, increased autophagy markers expression (Map1LC3a, Sqstm1) and protein (LC3AB II/I, p62), and an attenuation of the APAP-induced hypofibrinolytic state via (PAI-1) compared with WT mice 24 post-APAP treatment. MiR-21 inhibition could be a novel therapeutic approach to mitigate APAP-induced hepatotoxicity and enhance survival during the regenerative phase, particularly to alter regeneration, autophagy, and fibrinolysis. Specifically, miR-21 inhibition could be particularly useful when APAP intoxication is detected at its late stages and the only available therapy is minimally effective.

Liberation of daidzein by gut microbial β-galactosidase suppresses acetaminophen-induced hepatotoxicity in mice

Acetaminophen (APAP) overdose is a leading cause of drug-induced liver injury (DILI). The impact of the gut microbiota and associated metabolites on APAP and liver function remains unclear. We show that APAP disturbance is associated with a distinct gut microbial community, with notable decreases in Lactobacillus vaginalis. Mice receiving L.vaginalis showed resistance to APAP hepatotoxicity due to the liberation of the isoflavone daidzein from the diet by bacterial β-galactosidase. The hepatoprotective effects of L.vaginalis in APAP-exposed germ-free mice were abolished with a β-galactosidase inhibitor. Similarly, β-galactosidase-deficient L.vaginalis produced poorer outcomes in APAP-treated mice than the wild-type strain, but these differences were overcome with daidzein administration. Mechanistically, daidzein prevented ferroptotic death, which was linked to decreased expression of farnesyl diphosphate synthase (Fdps) that activated a key ferroptosis pathway involving AKT-GSK3β-Nrf2. Thus, liberation of daidzein by L.vaginalis β-galactosidase inhibits Fdps-mediated hepatocyte ferroptosis, providing promising therapeutic approaches for DILI.

HEPATOPROTECTIVE EFFECTS OF CHOLECALCIFEROL AND N-ACETYLCYSTEINE IN ACETAMINOPHEN INDUCED HEPATOTOXICITY IN MICE

Background: The liver is a critical factor that has a vital role in metabolism and excretion of various chemical substances and drugs. Liver harm is a major problem to health that challenges healthcare vendors and the pharmaceutical industry. Acute liver injuries caused by various toxic chemicals, drugs, high alcohol intake, and microbes are studied well. This study aimed to measure the out-turn of cholecalciferol in comparison to N-acetylcysteine in acetaminophen-induced hepatotoxicity in mice. Methods: It was an experimental randomized control trial carried out in the Department of Pharmacology, Islamic International Medical College in collaboration with National Institute of Health Islamabad. Forty adult Balb-C mice were divided into four groups with 10 mice in every group. Group 1 was the Negative control group, and the experimental groups 2, 3, and 4 were administered acetaminophen to set off hepatotoxicity which was confirmed after one week through measuring alanine transaminase (ALT) levels. Group 3 was then administered cholecalciferol, and group 4 was given N-acetylcysteine. Terminal sampling was done on day 28 to evaluate the results. Statistical analysis was accomplished on SPSS-22. Comparison among groups was done using one-way ANOVA and student’s t-test, and p<0.05 was taken statistically significant. Results: Mice of groups 3 and 4 significantly reduced ALT levels as compared to group 2. Cholecalciferol significantly decreased ALT levels in hepatotoxic mice with efficacy greater than N-acetylcysteine. Conclusion: Cholecalciferol is more efficacious in the reversal of acute liver injury as compared to N-acetylcysteine. Pak J Physiol 2023;19(1):14-16

Targeting IKKβ Activity to Limit Sterile Inflammation in Acetaminophen-Induced Hepatotoxicity in Mice.

The kinase activity of inhibitory κB kinase β (IKKβ) acts as a signal transducer in the activating pathway of nuclear factor-κB (NF-κB), a master regulator of inflammation and cell death in the development of numerous hepatocellular injuries. However, the importance of IKKβ activity on acetaminophen (APAP)-induced hepatotoxicity remains to be defined. Here, a derivative of caffeic acid benzylamide (CABA) inhibited the kinase activity of IKKβ, as did IMD-0354 and sulfasalazine which show therapeutic efficacy against inflammatory diseases through a common mechanism: inhibiting IKKβ activity. To understand the importance of IKKβ activity in sterile inflammation during hepatotoxicity, C57BL/6 mice were treated with CABA, IMD-0354, or sulfasalazine after APAP overdose. These small-molecule inhibitors of IKKβ activity protected the APAP-challenged mice from necrotic injury around the centrilobular zone in the liver, and rescued the mice from hepatic damage-associated lethality. From a molecular perspective, IKKβ inhibitors directly interrupted sterile inflammation in the Kupffer cells of APAP-challenged mice, such as damage-associated molecular pattern (DAMP)-induced activation of NF-κB activity via IKKβ, and NF-κB-regulated expression of cytokines and chemokines. However, CABA did not affect the upstream pathogenic events, including oxidative stress with glutathione depletion in hepatocytes after APAP overdose. N-acetyl cysteine (NAC), the only FDA-approved antidote against APAP overdose, replenishes cellular levels of glutathione, but its limited efficacy is concerning in late-presenting patients who have already undergone oxidative stress in the liver. Taken together, we propose a novel hypothesis that chemical inhibition of IKKβ activity in sterile inflammation could mitigate APAP-induced hepatotoxicity in mice, and have the potential to complement NAC treatment in APAP overdoses.

Hepatoprotective effect of obeticholic acid on acetaminophen induced hepatotoxicity in mice

Acetaminophen (APAP) is commonly used as analgesic and antipyretic drug for relieving mild and moderate pain, but at high doses produces hepatic necrosis. Though, Obeticholic acid (OCA) has been tested in range of diseases, its therapeutic potential against APAP-induced hepatic injury remains to be elucidated. Thus, in this study, we investigated the preventive effect of OCA along with N-acetylcysteine (NAC) and Silymarin (SIL) against acetaminophen-induced hepatotoxicity in mice. SIL (100 mg/kg, po) and OCA (30 mg/kg, po) were administered continuously for six days prior to APAP administration. After sixth dose, animas were fasted for 12 h and treated with 300 mg/kg APAP and then received SIL (100 mg/kg, po), NAC (500 mg/kg, ip) and OCA (30 mg/kg, po) at 1 h after APAP. Mice were sacrificed 6 h after APAP injection. Analysis of serum Aspartate aminotransferase (AST), Alanine aminotransferase (ALT), Alkaline phosphatase (ALP), liver glutathione (GSH) and histopathology were employed for assessment of hepatotoxicity. APAP group showed a significant increase in ALT, AST, ALP and centriolobular hepatic necrosis with a significant decrease in glutathione in comparison to control group. All these parameters were significantly improved in all the three treated groups when compared to APAP group. In conclusion, Obeticholic acid (OCA), Silymarin (SIL) and N-acetylcysteine (NAC) are suggested to protect against APAP-induced hepatotoxicity in mice by ameliorating liver enzymes, antioxidant effect and decreasing liver necrosis.

Hepatocyte-specific Mas activation enhances lipophagy and fatty acid oxidation to protect against acetaminophen-induced hepatotoxicity in mice

Acetaminophen (APAP) is the most common cause of drug-induced liver injury (DILI); however, treatment options are limited. Mas is a G protein-coupled receptor whose role in APAP-induced hepatotoxicity has not yet been examined. Intrahepatic Mas expression was determined in both human and mouse DILI models. Mas1-/-, AlbcreMas1f/f, Ppara-/-, Mas1-/-Ppara-/- and wild-type mice were challenged with APAP for the in vivo analyses of Mas-AKT-FOXO1 axis-dependent lipophagy and fatty acid oxidation (FAO), using pharmacological compounds and genetic tools. Liver samples were collected for RNA-sequencing, proteomics, metabolomics, lipidomics, and metabolic flux analysis. Live-imaging of liver and histological, biochemical, and molecular studies were performed to evaluate APAP-induced hepatotoxicity in mice. Primary hepatocytes and hepatic cell lines were exposed to APAP for in vitro analysis. Intrahepatic Mas expression was significantly upregulated in human and mouse DILI models. Mice with systemic, liver-specific, or hepatocyte-specific Mas1 deficiency were vulnerable to APAP-induced hepatotoxicity. They exhibited substantially impaired lipophagy and downstream FAO, which was accompanied by the activation of AKT and suppression of FOXO1. In addition, the prophylactic activation of Mas showed unbelievably ideal effects to protect mice from APAP challenge, with remarkably enhanced lipophagy and FAO dependent on the AKT-FOXO1 axis. Moreover, the protective effects of AVE0991 were substantially diminished by the inhibition of either lipophagy or FAO. The activation of Mas on hepatocytes enhanced AKT-FOXO1-dependent lipophagy and downstream FAO to protect mice from APAP-induced hepatotoxicity, suggesting that hepatocyte-specific Mas might be a novel therapeutic target for DILI. Mas signaling arises as a novel therapeutic target for patients with APAP overdose. Mas-AKT/FOXO1-fatty acid degradation pathway is critical for researchers to develop treatment strategies of APAP overdose. When Mas signaling is targeted, the extent of liver injury should be taken into account at the time of administration. These findings obtained from APAP-challenged mice still need to be confirmed in the clinics.

Therapeutic effect of 6-shogaol on acetaminophen-induced hepatotoxicity in mice: an experimental study.

Acetaminophen (APAP) is one of the most commonly used analgesics and antipyretics. It causes serious liver damage when taken in large quantities by adults or children. Also, 6-shogaol is an active compound obtained from ginger with anti-inflammatory and antioxidant properties. This study aimed at examining the therapeutic effect of 6-shogaol in APAP-induced hepatotoxicity. The mice were separated into five groups. After the mice were sacrificed, the levels of alanine aminotransferase (ALT), aspartate transaminase (AST), and alkaline phosphatase (ALP) in the blood, glutathione (GSH) level in the liver tissue homogenate, and levels of induced nitrite oxide synthetase (INOS) and total nitrite/nitrate were measured by spectrophotometric methods. APAP administration significantly increased the serum levels of ALT, AST, and ALP, INOS activity in liver tissue, and total nitrite/nitrate levels compared with control and significantly decreased GSH levels. After APAP toxicity, 6-shogaol and N-acetylcysteine (NAC) administration significantly decreased the levels of ALT, AST, INOS, and total nitrite/nitrate levels and significantly increased GSH levels compared with control. Also, 6-shogaol was found to be better than NAC in increasing the GSH level. The study showed that 6-shogaol might have an early therapeutic effect on APAP-induced liver damage.

Lipid-lowering, anti-inflammatory, and hepatoprotective effects of isorhamnetin on acetaminophen-induced hepatotoxicity in mice

Isorhamnetin is a hepatoprotective flavonoid molecule derived from the leaves and fruits of Hippophae rhamnoides L. However, the protective effect of isorhamnetin on acetaminophen (APAP) induced hepatotoxicity is still unknown. Thus, we aimed to investigate the lipid-lowering, anti-inflammatory, and hepatoprotective effects of isorhamnetin on APAP-induced hepatotoxicity in mice. Hepatotoxicity was induced by a single injection of APAP (300 mg/kg, intraperitoneally). Isorhamnetin (50 or 100 mg/kg, orally) and N-acetylcysteine (NAC) (200 mg/kg, orally), or vehicle control, were administered 1 h before the administration of APAP. Total antioxidant status (TAS) and total oxidative status (TOS) of liver tissue and levels of inflammatory factors (TNF-α, IL-1β, and IL-6) were analyzed by ELISA. Lipid profiles and liver function parameters were measured using an autoanalyzer. In addition, liver tissue was examined histopathologically. Isorhamnetin treatment significantly reduced the APAP-induced increase in the liver weight and liver index; it also reduced the APAP-induced increase in serum liver parameters (ALT, AST, ALP, and LDH) (p < 0.05). Isorhamnetin significantly reduced APAP-induced oxidative stress and inflammation by increasing TAS levels and decreasing TOS, TNF-α, IL-1β, and IL-6 levels (p < 0.05). Moreover, isorhamnetin treatment significantly regulated lipid profiles (TG, T-C, LDL-C, and HDL-C levels) that changed in response to APAP administration (p < 0.05). In histopathological examination, liver degeneration observed in the APAP group was significantly reduced in the NAC and isorhamnetin-treated groups (p < 0.05). This study suggests that isorhamnetin has a significant protective effect on APAP-induced hepatotoxicity in mice through its lipid-lowering, antioxidant, and anti-inflammatory effects.

Protective Effects of Interleukin-37 Expression against Acetaminophen-Induced Hepatotoxicity in Mice.

Aim Interleukin (IL)-37 is a new anti-inflammatory cytokine of the IL-1 family. This study aimed to determine the effects of IL-37 on acetaminophen (APAP)-induced liver injury. Materials and Methods IL-37 plasmids were injected into mice via a tail vein hydrodynamics-based gene delivery. Results Our results showed that IL-37 pretreatment significantly decreased serum alanine aminotransferase and aspartate aminotransferase levels, hepatic myeloperoxidase activity, and attenuated the histological liver damage. Compared to the APAP group, IL-37 administration decreased Kupffer cells numbers in the liver of APAP-induced hepatotoxicity in mice. Furthermore, IL-37 pretreatment reduced the expression of proinflammatory cytokines including tumor necrosis factor-α, IL-6, IL-17, and nuclear factor-κB (NF-κB) in APAP-induced mice. Conclusion These results demonstrate that delivery of IL-37 plasmid can ameliorate APAP-induced liver injury by reducing proinflammatory cytokines production and preventing the activation of the NF-κB signaling pathway. IL-37 may be a promising candidate against APAP-induced liver injury.

Diacerein counteracts acetaminophen-induced hepatotoxicity in mice via targeting NLRP3/caspase-1/IL-1\u03b2 and IL-4/MCP-1 signaling pathways

The current study aims at repurposing the anti-arthritic drug diacerein (DCN) for the treatment of acetaminophen hepatotoxicity and investigating the potential underlying mechanisms. Mice were randomly divided into six groups receiving either no treatment (control group), 20 mg/kg DCN i.p, 400 mg/kg acetaminophen i.p, DCN 4 h before acetaminophen, DCN 2 h after acetaminophen, or 400 mg/kg N-acetylcysteine (NAC) i.p, 2 h after acetaminophen. Biomarkers of liver dysfunction, oxidative stress, and apoptosis were assessed. Hepatic necroinflammatory changes were evaluated along with hepatic expression of NF-κB and caspase-1. The levels of NLRP3, IL-1β, IL-4, MCP-1, and TNF-α in the liver, as well as CYP2E1 mRNA expression, were measured. Diacerein significantly reduced biomarkers of liver dysfunction, oxidative stress, hepatocyte necrosis, and infiltration of neutrophils and macrophages whether administered 4 h before or 2 h after acetaminophen. Further, the effects were comparable to those of NAC. Diacerein also counteracted acetaminophen-induced hepatocellular apoptosis by increasing Bcl-2 and decreasing Bax and caspase-3 expression levels. Moreover, DCN normalized hepatic TNF-α and significantly decreased NF-κB p65 expression. Accordingly, DCN can prevent or reverse acetaminophen hepatotoxicity in mice, suggesting potential utility as a repurposed drug for clinical treatment.

Kahweol Protects against Acetaminophen-Induced Hepatotoxicity in Mice through Inhibiting Oxidative Stress, Hepatocyte Death, and Inflammation

Acetaminophen (APAP) can cause acute liver failure, but treatment options are still limited. Kahweol is the main diterpene compound of coffee and possesses antioxidant and anti-inflammatory properties. Emerging evidence suggests that this natural diterpene exerts favorable effects on several inflammatory diseases. However, the action of kahweol on APAP toxicity has not been addressed. The purpose of this study was to explore whether kahweol has a protective activity against APAP-induced hepatotoxicity and to investigate the mechanism. Administration of kahweol reduced serum levels of liver injury indicators and ameliorated histological abnormalities in APAP-treated mice. Kahweol inhibited lipid peroxidation and nucleic acid oxidation with restoration of glutathione content and stimulation of nuclear factor erythroid-2-related factor 2-dependent cellular defense system. Hepatocyte death was also decreased by kahweol, which was associated with inhibition of endoplasmic reticulum (ER) stress. Moreover, kahweol reduced hepatic levels of inflammatory mediators, inhibited nuclear factor-κB activation, and attenuated infiltration of neutrophils and macrophages. These findings suggest that kahweol has a protective activity against APAP-induced liver injury and this effect is related to the suppression of oxidative stress, hepatocyte death, ER stress, and inflammation.

Interruption of bile acid uptake by hepatocytes after acetaminophen overdose ameliorates hepatotoxicity

Background & AimsAcetaminophen (APAP) overdose remains a frequent cause of acute liver failure, which is generally accompanied by increased levels of serum bile acids (BAs). However, the pathophysiological role of BAs remains elusive. Herein, we investigated the role of BAs in APAP-induced hepatotoxicity.MethodsWe performed intravital imaging to investigate BA transport in mice, quantified endogenous BA concentrations in the serum of mice and patients with APAP overdose, analyzed liver tissue and bile by mass spectrometry and MALDI-mass spectrometry imaging, assessed the integrity of the blood-bile barrier and the role of oxidative stress by immunostaining of tight junction proteins and intravital imaging of fluorescent markers, identified the intracellular cytotoxic concentrations of BAs, and performed interventions to block BA uptake from blood into hepatocytes.ResultsPrior to the onset of cell death, APAP overdose causes massive oxidative stress in the pericentral lobular zone, which coincided with a breach of the blood-bile barrier. Consequently, BAs leak from the bile canaliculi into the sinusoidal blood, which is then followed by their uptake into hepatocytes via the basolateral membrane, their secretion into canaliculi and repeated cycling. This, what we termed ‘futile cycling’ of BAs, led to increased intracellular BA concentrations that were high enough to cause hepatocyte death. Importantly, however, the interruption of BA re-uptake by pharmacological NTCP blockage using Myrcludex B and Oatp knockout strongly reduced APAP-induced hepatotoxicity.ConclusionsAPAP overdose induces a breach of the blood-bile barrier which leads to futile BA cycling that causes hepatocyte death. Prevention of BA cycling may represent a therapeutic option after APAP intoxication.Lay summaryOnly one drug, N-acetylcysteine, is approved for the treatment of acetaminophen overdose and it is only effective when given within ∼8 hours after ingestion. We identified a mechanism by which acetaminophen overdose causes an increase in bile acid concentrations (to above toxic thresholds) in hepatocytes. Blocking this mechanism prevented acetaminophen-induced hepatotoxicity in mice and evidence from patients suggests that this therapy may be effective for longer periods after ingestion compared to N-acetylcysteine.

Extract of Triticum aestivum Sprouts Suppresses Acetaminophen-Induced Hepatotoxicity in Mice by Inhibiting Oxidative Stress.

Wheat (Triticum aestivum L.) is the oldest known food crop, and many studies have reported that wheat shoots (i.e., wheatgrass) possess anti-cancer, anti-inflammatory, and antioxidant activities. However, the potentially ameliorative effect of wheat shoots on hepatotoxicity caused by high doses of N-acetyl-para-aminophenol (acetaminophen, APAP) has yet to be reported. C57BL/6 mice received daily oral TAE (100 or 200 mg/kg), positive control (silymarin 100 mg/kg), or negative control (saline vehicle) treatments for 7 days prior to intraperitoneal APAP injection. Histological, serum (ELISA), Western blotting, and quantitative PCR analyses of excised liver tissues were then performed. Pre-treatment with TAE (100 or 200 mg/kg) ameliorated APAP-induced pathological damage (i.e., hepatotoxic lesions), reduced serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, and also ameliorated APAP-induced increases in oxidative stress, thereby inhibiting oxidative liver damage and reducing the expression of inflammatory cytokines. In addition, TAE pre-treatment inhibited the expression of Cytochrome P4502E1 (CYP2E1), which is a key enzyme in the onset of APAP-induced hepatotoxicity, suppressed the expression of the target proteins regulated by the antioxidant enzyme Nrf2, and suppressed hepatocyte apoptosis. These findings suggest that TAE is an attractive therapeutic candidate that exhibits potential hepatoprotective activity by inhibiting oxidative stress, inflammation, apoptosis, and liver damage.

Exogenous activation of toll-like receptor 5 signaling mitigates acetaminophen-induced hepatotoxicity in mice

Acetaminophen (APAP) poisoning is the most common cause of drug-induced acute liver injury (ALI). Our results showed that toll-like receptor 5 (TLR5) was abundantly expressed in hepatocytes and dramatically downregulated in the toxic mouse livers. Hence, we herein investigated the role of TLR5 signaling after APAP overdose. Mice were intraperitoneally (i.p.) injected with APAP to induce ALI, and then injected with flagellin at one hour after APAP administration. Flagellin attenuated APAP-induced ALI based on decreased histopathologic lesions, serum biochemical, oxidative stress, and inflammation. Furthermore, the protective effects of flagellin were abolished by TH1020 (a TLR5 antagonist) treatment. These results suggest that flagellin exerted protective effects on ALI via TLR5 activation. Mechanistically, flagellin injection promoted the translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) to the nucleus in hepatocytes. Consistent with the in vivo results, flagellin increased the activation of Nrf2 in hepatocytes, resulting in decreased APAP toxicity. ML385, a selective inhibitor of Nrf2, abolished the flagellin-mediated hepatoprotective effects in damaged livers and hepatocytes. Additionally, the flagellin-induced Nrf2 translocation was dependent upon the activation of TLR5-JNK/p38 pathways. These findings suggest that TLR5 signaling-induced Nrf2 activation, at least partially, contributed to the protection against APAP-induced ALI by flagellin treatment.