Mechanistic studies on the alleviation of ANIT-induced cholestatic liver injury by Polygala fallax Hemsl. polysaccharides.

ETHNOPHARMACOLOGICAL RELEVANCE: Polygala fallax Hemsl. is a traditional folk medicine commonly used by ethnic minorities in the Guangxi Zhuang Autonomous Region, and has a traditional application in the treatment of liver disease. Polygala fallax Hemsl. polysaccharides (PFPs) are of interest for their potential health benefits. AIM OF THIS STUDY: This study explored the impact of PFPs on a mouse model of cholestatic liver injury (CLI) induced by alpha-naphthyl isothiocyanate (ANIT), as well as the potential mechanisms. MATERIALS AND METHODS: A mouse CLI model was constructed using ANIT (80 mg/kg) and intervened with different doses of PFPs or ursodeoxycholic acid. Their serum biochemical indices, hepatic oxidative stress indices, and hepatic pathological characteristics were investigated. Then RNA sequencing was performed on liver tissues to identify differentially expressed genes and signaling pathways and to elucidate the mechanism of liver protection by PFPs. Finally, Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting were used to verify the differentially expressed genes. RESULTS: Data analyses showed that PFPs reduced the levels of liver function-related biochemical indices, such as ALT, AST, AKP, TBA, DBIL, and TBIL. PFPs up-regulated the activities of SOD and GSH, down-regulated the contents of MDA, inhibited the release of IL-1ß, IL-6, and TNF-α, or promoted IL-10. Pathologic characterization of the liver revealed that PFPs reduced hepatocyte apoptosis or necrosis. The RNA sequencing indicated that the genes with differential expression were primarily enriched for the biosynthesis of primary bile acids, secretion or transportation of bile, the reactive oxygen species in chemical carcinogenesis, and the NF-kappa B signaling pathway. In addition, the results of qRT-PCR and Western blotting analysis were consistent with those of RNA sequencing analysis. CONCLUSIONS: In summary, this study showed that PFPs improved intrahepatic cholestasis and alleviated liver damage through the modulation of primary bile acid production, Control of protein expression related to bile secretion or transportation, decrease in inflammatory reactions, and inhibition of oxidative pressure. As a result, PFPs might offer a hopeful ethnic dietary approach for managing intrahepatic cholestasis.

Gancao decoction attenuates hepatic necroptosis via activating caspase 8 in cholestatic liver injury.

ETHNOPHARMACOLOGICAL RELEVANCE: Gancao Decoction (GCD) is widely used to treat cholestatic liver injury. However, it is unclear whether is related to prevent hepatocellular necroptosis. AIM OF THE STUDY: The purpose of this study is to clarify the therapeutic effects of GCD against hepatocellular necroptosis induced by cholestasis and its active components. MATERIALS AND METHODS: We induced cholestasis model in wild type mice by ligating the bile ducts or in Nlrp3-/- mice by intragastrical administering Alpha-naphthylisothiocyanate (ANIT). Serum biochemical indices, liver pathological changes and hepatic bile acids (BAs) were measured to evaluate GCD's hepatoprotective effects. Necroptosis was assessed by expression of hallmarkers in mice liver. Moreover, the potential anti-necroptotic effect of components from GCD were investigated and confirmed in ANIT-induced cholestasis mice and in primary hepatocytes from WT mouse stimulated with Tumor Necrosis Factor alpha (TNF-α) and cycloheximide (CHX). RESULTS: GCD dose-dependently alleviated hepatic necrosis, reduced serum aminotranferase activity in both BDL and ANIT-induced cholestasis models. More importantly, the expression of hallmarkers of necroptosis, including MLKL, RIPK1 and RIPK3 phosphorylation (p- MLKL, p-RIPK1, p-RIPK3) were reduced upon GCD treatment. Glycyrrhetinic acid (GA), the main bioactive metabolite of GCD, effectively protected against ANIT-induced cholestasis, with decreased expression of p-MLKL, p-RIPK1 and p-RIPK3. Meanwhile, the expression of Fas-associated death domain protein (FADD), long isoform of cellular FLICE-like inhibitory protein (cFLIPL) and cleaved caspase 8 were upregulated upon GA treatment. Moreover, GA significantly increased the expression of active caspase 8, and reduced that of p-MLKL in TNF-α/CHX induced hepatocytes necroptosis. CONCLUSIONS: GCD substantially inhibits necroptosis in cholestatic liver injury. GA is the main bioactive component responsible for the anti-necroptotic effects, which correlates with upregulation of c-FLIPL and active caspase 8.

Allocholic acid protects against α-naphthylisothiocyanate-induced cholestasis in mice by ameliorating disordered bile acid homeostasis.

Cholestasis is a pathological condition characterized by disruptions in bile flow, leading to the accumulation of bile acids (BAs) in hepatocytes. Allocholic acid (ACA), a unique fetal BA known for its potent choleretic effects, reappears during liver regeneration and carcinogenesis. In this research, we investigated the protective effects and underlying mechanisms of ACA against mice with cholestasis brought on by α-naphthylisothiocyanate (ANIT). To achieve this, we combined network pharmacology, targeted BA metabolomics, and molecular biology approaches. The results demonstrated that ACA treatment effectively reduced levels of serum AST, ALP, and DBIL, and ameliorated the pathological injury caused by cholestasis. Network pharmacology analysis suggested that ACA primarily regulated BA and salt transport, along with the signaling pathway associated with bile secretion, to improve cholestasis. Subsequently, we examined changes in BA metabolism using UPLC-MS/MS. The findings indicated that ACA pretreatment induced alterations in the size, distribution, and composition of the liver BA pool. Specifically, it reduced the excessive accumulation of BAs, especially cholic acid (CA), taurocholic acid (TCA), and ß-muricholic acid (ß-MCA), facilitating the restoration of BA homeostasis. Furthermore, ACA pretreatment significantly downregulated the expression of hepatic BA synthase Cyp8b1, while enhancing the expression of hepatic efflux transporter Mrp4, as well as the renal efflux transporters Mdr1 and Mrp2. These changes collectively contributed to improved BA efflux from the liver and enhanced renal elimination of BAs. In conclusion, ACA demonstrated its potential to ameliorate ANIT-induced liver damage by inhibiting BA synthesis and promoting both BA efflux and renal elimination pathways, thus, restoring BA homeostasis.

Silymarin protects the liver from α-naphthylisothiocyanate-induced cholestasis by modulating the expression of genes involved in bile acid homeostasis.

Cholestasis is characterized by impaired bile flow which results in inflammation, cirrhosis, and ultimately liver failure. The current study is aimed to evaluate the anti-cholestatic effect of silymarin against α-naphthylisothiocyanate (ANIT) induced cholestasis. Mice were gavaged with various doses of silymarin or ursodeoxycholic acid (UDCA) for 19 days. Then they were challenged with α-naphthylisothiocyanate (ANIT) and after 48 hours the animals were sacrificed to obtain blood and liver sections. Serum levels of bilirubin, aspartate transaminase (AST), alanine transaminase (ALP), and liver histology were analyzed. mRNA expression of selected transporters (Bile salt export pump (BSEP) and sodium taurocholate cotransporting polypeptide (NTCP)) and proteins (farnesoid x receptor (FXR) and Cytochrome P450 Family 7 Subfamily A Member 1 (Cyp7a1)) involved in bile acids biosynthesis, excretion and uptake were also evaluated by quantitative PCR. The results indicated that the serum levels of bilirubin, AST, and ALP were significantly higher in a cholestatic model group as compared to an untreated control group. However, in silymarin groups, the serum level of these parameters is significantly lower than in a cholestatic model group. Liver histology also showed that silymarin prevents ANIT-induced hepatic injury. mRNA expression of FXR, BSEP, and NTCP was downregulated and expression of Cyp7a1 was upregulated in a cholestatic model group as compared to an untreated control group. However, in silymarin treatment groups, the expression of FXR, BSEP and NTCP was upregulated and the expression of Cyp7a1 was downregulated as compared to the cholestatic model group. In conclusion, silymarin could alleviate hepatic injury by modulating the expression of genes involved in bile acid homeostasis.

Ginsenosides Restore Lipid and Redox Homeostasis in Mice with Intrahepatic Cholestasis through SIRT1/AMPK Pathways.

Intrahepatic cholestasis (IC) occurs when the liver and systemic circulation accumulate bile components, which can then lead to lipid metabolism disorders and oxidative damage. Ginsenosides (GS) are pharmacologically active plant products derived from ginseng that possesses lipid-regulation and antioxidation activities. The purpose of this study was to evaluate the possible protective effects of ginsenosides (GS) on lipid homeostasis disorder and oxidative stress in mice with alpha-naphthylisothiocyanate (ANIT)-induced IC and to investigate the underlying mechanisms. A comprehensive strategy via incorporating pharmacodynamics and molecular biology technology was adopted to investigate the therapeutic mechanisms of GS in ANIT-induced mice liver injury. The effects of GS on cholestasis were studied in mice that had been exposed to ANIT-induced cholestasis. The human HepG2 cell line was then used in vitro to investigate the molecular mechanisms by which GS might improve IC. The gene silencing experiment and liver-specific sirtuin-1 (SIRT1) knockout (SIRT1LKO) mice were used to further elucidate the mechanisms. The general physical indicators were assessed, and biological samples were collected for serum biochemical indexes, lipid metabolism, and oxidative stress-related indicators. Quantitative PCR and H&E staining were used for molecular and pathological analysis. The altered expression levels of key pathway proteins (Sirt1, p-AMPK, Nrf2) were validated by Western blotting. By modulating the AMPK protein expression, GS decreased hepatic lipogenesis, and increased fatty acid ß-oxidation and lipoprotein lipolysis, thereby improving lipid homeostasis in IC mice. Furthermore, GS reduced ANIT-triggered oxidative damage by enhancing Nrf2 and its downstream target levels. Notably, the protective results of GS were eliminated by SIRT1 shRNA in vitro and SIRT1LKO mice in vivo. GS can restore the balance of the lipid metabolism and redox in the livers of ANIT-induced IC models via the SIRT1/AMPK signaling pathway, thus exerting a protective effect against ANIT-induced cholestatic liver injury.

Combination of resveratrol and luteolin ameliorates α-naphthylisothiocyanate-induced cholestasis by regulating the bile acid homeostasis and suppressing oxidative stress.

Cholestasis is a common liver injury without any effective therapeutic drugs so far. Resveratrol (RES) and luteolin (LUT) are natural polyphenols that exert protective effects on multiple liver injuries. Coadministration of RES and LUT could significantly improve the bioavailability of LUT and increase the systemic exposure to RES, and the combined treatment could also benefit from their multi-component and multi-target characteristics. Our current aim is to study the protective effects of coadministration of RES and LUT on α-naphthylisothiocyanate (ANIT)-induced cholestasis. Serum biochemical indices and liver histopathology in rats indicated that coadministration of RES and LUT could improve liver function by suppressing oxidative stress. Dysregulated bile acid (BA) homeostasis is a significant pathological feature of cholestasis, which was determined to explore the potential biomarkers and to clarify the protection mechanism of coadministration of RES and LUT. The levels of cholic acid, chenodeoxycholic acid, taurine conjugates and glycine conjugates, and the ratios of taurine conjugates to their free forms could be used as diagnosis indicators for cholestasis in rats. Furthermore, the coadministration of RES and LUT could restore the BA levels and exert better protective effects than administration alone. This study suggested that the coadministration of RES and LUT could protect against ANIT-induced cholestasis and the mechanism was closely related to regulating BA homeostasis and suppressing oxidative stress.

Nrf2-Dependent Protective Effect of Paeoniflorin on α-Naphthalene Isothiocyanate-Induced Hepatic Injury.

The pathological mechanism of cholestatic hepatic injury is associated with oxidative stress, hepatocyte inflammation, and dysregulation of hepatocyte transporters. Paeonia lactiflora Pall. and its compound can improve hepatic microcirculation, dilate bile duct, and promote bile flow, which is advantageous to ameliorate liver damage. Paeoniflorin (PEA), as the main efficacy component of Paeonia lactiflora Pall., has multiple pharmacological effects. PEA improves liver injury, but it remains obscure whether the protective action on [Formula: see text]-naphthalene isothiocyanate (ANIT)-induced cholestatic liver injury is dependent on the NF-E2 p45-related Factor 2 (Nrf2) signaling pathway. In this study, C57BL/6 mice were administrated with 80 mg⋅kg[Formula: see text]⋅d[Formula: see text] ANIT followed by PEA (75, 150, and 300 mg⋅kg[Formula: see text]⋅d[Formula: see text]) orally for 10 days, respectively. Tissue histology and liver function were detected, including serum enzymes, gallbladder (GB) weight, phenobarbital-induced sleeping time (PEN-induced ST), hepatic uridine di-phosphoglucuronosyltransferase (UDPG-T), malondialdehyde (MDA), and glutathione (GSH). The expressions of protein Nrf2, sodium taurocholate cotransporting polypeptide (Ntcp), and NADPH oxidase 4 (Nox4) were evaluated. Nrf2 plasmid or siRNA-Nrf2 transfection on LO2 cells and Nrf2-/- mice were used to explore the liver protective mechanism of PEA. Compared to ANIT-treated mice, PEA decreased serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), total bilirubin (TBIL), direct bilirubin (DBIL), total bile acid (TBA), and phenobarbital-induced sleeping time. The bile secretion, hepatic UDPG-T, MDA, GSH, and liver histology were improved. The expressions of protein Nrf2 and Ntcp in liver tissues increased, but Nox4 decreased. After Nrf2 plasmid or small interfering RNA (siRNA)-Nrf2 transfection, the protective effects of PEA on LO2 cells were, respectively, strengthened or weakened. Moreover, PEA had no significant effects on ANIT-treated Nrf2-/- mice. Our results suggest that Nrf2 is essential for PEA protective effects on ANIT-induced liver injury.

Oleanolic acid alleviates ANIT-induced cholestatic liver injury by activating Fxr and Nrf2 pathways to ameliorate disordered bile acids homeostasis.

BACKGROUND: Cholestasis is a clinical syndrome with high incidence and few effective treatments. Oleanolic acid (OA) is a triterpenoid compound with anti-cholestatic effects. Studies using bile duct ligation or lithocholic acid modeling have shown that the alleviating effect of OA on cholerosis is related to the regulation of nuclear factor erythroid 2 related factor (Nrf2) or farnesoid X receptor (Fxr). PURPOSE: This study aims to investigate the underlying mechanism of OA against alpha-naphthylisothiocyanate (ANIT)-induced cholestatic liver injury based on Nrf2 and Fxr dual signaling pathways. METHODS: The ANIT-induced rats model was used with or without OA treatment. Serum biochemical indexes, liver histopathological changes and glutathione level were examined. Bile acids (BAs) targeted metabolomics based on UHPLC-MS/MS were performed. siRNA, RT-qPCR and western blot analysis were used to prove the role of Fxr and Nrf2 pathway in OA's anti-cholestatic liver injury in vivo and in vitro. RESULTS: OA significantly alleviated ANIT-induced liver injury in rats, reduced primary bile acids, accelerated metabolism of BAs and reduced the intrahepatic accumulation of BAs. The expressions of bile salt export pump (Bsep), Na+-taurocholic cotransport polypeptide (Ntcp), UDP-glucuronyl transferase 1a1 (Ugt1a1) and Fxr in rat liver were markedly up-regulated, the activation of Nrf2 was promoted, and the expression of cholesterol 7α-hydroxylase (Cyp7a1) was decreased after OA treatment. Moreover, Fxr or Nrf2 silencing attenuated the regulation of OA on BAs homeostasis related transporters and enzymes in rat primary hepatocytes. CONCLUSION: OA may regulate BAs-related transporters and metabolic enzymes by activating Fxr and Nrf2 pathways, thus alleviating the cholestatic liver injury induced by ANIT.

Cultured bear bile powder ameliorates acute liver injury in cholestatic mice via inhibition of hepatic inflammation and apoptosis.

ETHNOPHARMACOLOGICAL RELEVANCE: Natural bear bile powder (NBBP) is a traditional Chinese medicine used for treating liver dysfunction. Cultured bear bile powder (CBBP), which is produced using biotransformation of chicken bile, acts as an appropriate substitute for NBBP when treating cholestatic liver injury. AIM OF THE STUDY: To investigate the molecular mechanisms underlying the hepatoprotective effects of CBBP in an α-naphthylisothiocyanate (ANIT)-induced cholestatic mouse model. MATERIALS AND METHODS: Cholestatic mice were pretreated with CBBP or NBBP via oral gavage once a day for two weeks. Their blood biochemistry and liver histopathology were then evaluated using standard protocols. Western blot analyses, real-time polymerase chain reaction, and immunohistochemistry were used to evaluate changes in the protein levels and gene expression profiles of factors associated with hepatic inflammation and apoptosis in cholestatic mice. RESULTS: CBBP significantly decreased the serum indices of liver injury, and ameliorated neutrophil infiltration and hepatocyte necrosis within liver tissue of cholestatic mice. Expression of the inflammatory factors, such as tumor necrosis factor-α, interleukin-1ß (IL-1ß), IL-6, monocyte chemoattractant protein-1, and intercellular adhesion molecule 1, was significantly reduced in CBBP-treated cholestatic mice. Moreover, proteins involved in the toll-like receptor 4/myeloid differentiation factor 88/nuclear factor-kappa B (TLR4/Myd88/NF-κB) signaling pathway, such as CD14, TLR4, Myd88, and NF-κB, that were increased in cholestatic mice, were downregulated by CBBP. Meanwhile, increased expression of the apoptosis-related proteins, caspase-3 and Bax, in cholestatic mice was reversed by CBBP treatment. CONCLUSION: CBBP treatment alleviates ANIT-induced cholestasis and liver injury by reducing hepatocyte inflammation and apoptosis.

Dolomiaea souliei ethyl acetate extract protected against α-naphthylisothiocyanate-induced acute intrahepatic cholestasis through regulation of farnesoid x receptor-mediated bile acid metabolism.

BACKGROUND: Cholestasis is characterized by accumulation of bile components in liver and systemic circulation. Restoration of bile acid homeostasis via activating farnesoid x receptor (FXR) is a promising strategy for the treatment of cholestasis. FXR-SHP (small heterodimer partner) axis plays an important role in maintaining bile acid homeostasis. PURPOSE: To investigate the anti-cholestasis effect of Dolomiaea souliei (Franch.) C.Shih (D. souliei) and clarify its underlying mechanism against α-naphthylisothiocyanate (ANIT) induced acute intrahepatic cholestasis. METHODS: ANIT-induced Sprague-Dawley rats were employed to investigate the anti-cholestasis effect of D. souliei ethyl acetate extract (DSE). Ursodeoxycholic acid (UDCA) was used as positive control. Bile flow and blood biochemical parameters were measured. Liver histopathological examination was conducted via hematoxylin-eosin staining. Western blot analysis was carried out to evaluate the protein levels related to bile acids metabolism and inflammation. The interactions between FXR and costunolide or dehydrocostus lactone, were conducted by molecular docking experiments. The effect of costunolide and dehydrocostus lactone on aspartate aminotransferase (AST), alanine aminotransferase (ALT) levels and FXR expression were also evaluated using guggulsterone-induced L02 cells. RESULTS: DSE could promote bile excretions and protect against ANIT-induced liver damage in cholestasis rats. Protein levels of FXR, SHP, Na+/taurocholate cotransporter (NTCP), bile salt export pump (BSEP), multidrug resistance-associated protein 2 (MRP2) were increased and the expressions of cholesterol 7α-hydroxylase (CYP7A1) and sterol 27-hydroxylase (CYP27A1) were decreased by DSE. Meanwhile, the anti-inflammatory factors, tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), interleukin-6 (IL-6) were also significantly increased, and the pro-inflammatory factor, interleukin-10 (IL-10), was significantly decreased in rats of DSE groups. Molecular docking revealed that costunolide and dehydrocostus lactone could be well docked into the FXR protein molecule, and hydrophobic interactions played the main function. Costunolide could reverse the increased AST and ALT levels and increase the FXR expression in guggulsterone-induced L02 cells. CONCLUSION: DSE had an anti-cholestasis effect by activating FXR-SHP axis, inhibiting synthesis of bile acid, and increasing bile secretion, together with inflammatory response and improving liver injury. Costunolide may be the main active component. This study provided a potential therapeutic mechanism for D. souliei as an anti-cholestasis medicine in the treatment of cholestasis liver diseases.

Dehydrodiconiferyl alcohol, a lignan from Herpetospermum pedunculosum, alleviates cholestasis by activating pathways associated with the farnesoid X receptor.

BACKGROUND: In our previous study, we demonstrated the hepatoprotective effect of Herpetospermum pedunculosum in cholestatic rats. A bioassay-guided study also led to the identification and isolation of a lignan, dihydrodiconiferyl alcohol (DA) from the seeds of H. pedunculosum. PURPOSE: To investigate whether DA could alleviate cholestasis and determine the mechanisms underlying such action. METHODS: Male Sprague-Dawley (SD) rats were administered with DA (10, 20 or 40 mg/kg) intragastrically once daily for 7 days prior to treatment with α-naphthylisothiocyanate (ANIT) (60 mg/kg). We then evaluated the levels of a range of serum indicators, determined bile flow, and carried out histopathological analyses. Western blotting was then used to investigate the levels of inflammatory mediators and the Farnesoid X Receptor (FXR), proteins involved in the downstream biosynthesis of bile acids, and a range of transport proteins. Molecular docking was used to simulate the interaction between DA and FXR. Cell viability of human hepatocytes (L-02) cells was determined by MTT. Then, we treated guggulsterone-inhibited L-02 cells, Si-FXR L-02 cells, and FXR-overexpression cells with the FXR agonist GW4064 (6 µM) or DA (25, 50 and 100 µM) for 24 h before detecting gene and protein expression by RT-PCR and western blotting, respectively. RESULTS: DA significantly attenuated ANIT-induced cholestasis in SD rats by reducing liver function indicators in the serum, increasing bile flow, improving the recovery of histopathological injuries in the liver, and by alleviating pro-inflammatory cytokines in the liver. DA also increased the expression levels of FXR and altered the levels of downstream proteins in the liver tissues, thus indicating that DA might alleviate cholestasis by regulating the FXR. Molecular docking simulations predicted that DA was as an agonist of FXR. In vitro mechanical studies further showed that DA increased the mRNA and protein expression levels of FXR, Small Heterodimer Partner 1/2, Bile Salt Export Pump, Multidrug Resistance-associated Protein 2, and Na+/taurocholate Co-transporting Polypeptide, in both guggulsterone-inhibited and Si-FXR L-02 cells. Moreover, DA enhanced the mRNA and protein expression of FXR, and its downstream genes and proteins, in L-02 cells containing an FXR-overexpression plasmid. CONCLUSION: DA may represent an effective agonist for FXR has significant therapeutic potential for the treatment of cholestatic liver injury.

Picroside II protects against cholestatic liver injury possibly through activation of farnesoid X receptor.

BACKGROUD: Cholestasis, accompanied by the accumulation of bile acids in body, may ultimately cause liver failure and cirrhosis. There have been limited therapies for cholesteric disorders. Therefore, development of appropriate therapeutic drugs for cholestasis is required. Picroside II is a bioactive component isolated from Picrorhiza scrophulariiflora Pennell, its mechanistic contributions to the anti-cholestasis effect have not been fully elucidated, especially the role of picroside II on bile acid homeostasis via nuclear receptors remains unclear. PURPOSE: This study was designed to investigate the hepatoprotective effect of picroside II against alpha-naphthylisothiocyanate (ANIT)-induced cholestatic liver injury and elucidate the mechanisms in vivo and in vitro. METHODS: The ANIT-induced cholestatic mouse model was used with or without picroside II treatment. Serum and bile biochemical indicators, as well as liver histopathological changes were examined. siRNA, Dual-luciferase reporter, quantitative real-time PCR and Western blot assay were used to demonstrate the farnesoid X receptor (FXR) pathway in the anti-cholestasis effects of picroside II in vivo and in vitro. RESULTS: Picroside II exerted hepatoprotective effect against ANIT-induced cholestasis by impaired hepatic function and tissue damage. Picroside II increased bile acid efflux transporter bile salt export pump (Bsep), uptake transporter sodium taurocholate cotransporting polypeptide (Ntcp), and bile acid metabolizing enzymes sulfate transferase 2a1 (Sult2a1) and UDP-glucuronosyltransferase 1a1 (Ugt1a1), whereas decreased the bile acid synthesis enzymes cholesterol 7α-hydroxylase (Cyp7a1) and oxysterol 12α-hydroxylase (Cyp8b1). In addition, expression of FXR and the target gene Bsep was increased, whereas aryl hydrocarbon receptor (AhR), pregnane X receptor (PXR), peroxisome proliferator-activated receptor alpha (PPARα) and their corresponding target genes were not significantly influenced by picroside II under cholestatic conditions. Furthermore, regulation of transporters and enzymes involved in bile acid homeostasis by picroside II were abrogated by FXR silencing in mouse primary cultured hepatocytes. Dual-luciferase reporter assay performed in HepG2 cells demonstrated FXR activation by picroside II. CONCLUSION: Our findings demonstrate that picroside II exerts protective effect on ANIT-induced cholestasis possibly through FXR activation that regulates the transporters and enzymes involved in bile acid homeostasis. Picroside II might be an effective approach for the prevention and treatment of cholestatic liver diseases.

Formononetin ameliorates cholestasis by regulating hepatic SIRT1 and PPARα.

Cholestasis, which is characterized by bile acid (BA) overload within the hepatocytes, is a major contributor to liver injury. The dysregulation of bile acid homeostasis, such as excessive bile acid synthesis and defected secretion, leads to intracellular retention of hydrophobic bile acid which undermines the physiological function of hepatocytes. Cholestasis can further develop into hepatic fibrosis and cirrhosis, and eventually life-threating liver failure. In the liver, BA-activated FXR can reduce hepatic BA concentration by negative feedback regulation. Clinically, FXR and PPARα are the pharmacological targets of obeticholic acid and fenofibrate for the treatment of primary biliary cirrhosis, respectively. Formononetin, a natural isoflavone compound, exerts beneficial effects in various biological processes, such as anti-inflammation, anti-tumor. However, the role of formononetin in bile acid metabolism remains unclear. Herein, we show that formononetin improves hepatic/systemic bile acid metabolism and protects against ANIT-induced liver injury. Mechanistically, formononetin improves the genes profile orchestrating bile acid homeostasis through modulating SIRT1-FXR signaling pathway. Moreover, formononetin attenuated ANIT-induced inflammatory response by inactivating JNK inflammation pathway in PPARα dependent manner. Taken together, our study demonstrates that formononetin ameliorates hepatic cholestasis by upregulating expression of SIRT1 and activating PPARα, which is an important anti-cholestatic mechanism of formononetin.

Effect of compound Yindan decoction on alpha-naphthylisothiocyanate-Induced acute intrahepatic cholestasis in rats.

OBJECTIVE: To investigate the therapeutic mechanism of compound Yindan decoction (CYD) in a rat model of acute intrahepatic cholestatic (AIC). METHODS: A total of 108 adult male rats were randomly divided into control (n = 18) and AIC groups (n = 90). AIC was induced in rats using alpha-naphthylisothiocyanate (ANIT) (75 mg/kg, 10 mL/kg in corn oil, p. o. ). Then, 90 AIC rats were randomly divided into five groups: a control group (n = 18), a CYD high dose group (n = 18), a CYD middle dose group (n = 18), a CYD low dose group (n = 18), and a ursodeoxycholic acid (UDCA) group (n = 18). According to sampling time, each group was subdivided into three subgroups: 24 h (n = 6), 48 h (n = 6), and 72 h groups (n = 6). The CYD-high, -middle and -low groups were orally administered 24.48, 12.24, and 6.12 g·kg－1·d－1 modified CYD, respectively, while the model group was given 20 mL/kg of body weight of distilled water once a day. The UDCA group was given 67. 5 mg·kg － 1·d － 1 UDCA once a day. Radioimmunity assay was used to detect the activity of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), gamma-glutamyl transpeptidase (GGT) and the levels of total bilirubin (TBil) and indirect biliruin (DBil) in rats. Reverse transcription quantitative polymerase chain reaction (qRT-PCR), Western blot analysis, and immunohistochemistry were used to detect multidrug resistance-associated protein 2 (MRP2) expression. In vitro, HepG2 hepatocellular carcinoma cells were treated with CYD medicated serum at a concentration of 15 mol/L. MRP2 and retinoid X receptor alpha (RXRα) expression was analyzed by qRT-PCR and Western blotting. RESULTS: Serum levels of ALT, AST, GGT, ALP, TBil, and DBil were significantly reduced in the CYD and positive drug groups compared with the control group (P < 0. 05 and P < 0.01, respectively). Pathological changes in rat liver tissues at 72 h in the CYD-high and -medium dose groups and positive drug group were not significant compared with the control group. CYD and UDCA treatment ameliorated ANIT-induced biliary epithelial cell proliferation. Neutrophil infiltration was rare and little focal necrosis was observed in lobules in the CYD-high and -medium dose groups and UDCA group at 72 h. Compared with the control group, the expression of MRP2 mRNA and MRP2 protein in the liver tissue of the CYD groups was significantly increased (P < 0. 05 and P < 0. 01, respectively). MRP2 expression and RXRα nuclear receptor mRNA and protein levels in the CYD groups were significantly increased compared with the control and UDCA groups (P < 0. 01). CONCLUSION: CYD can alleviate cholestasis in ANIT-induced AIC rats, and the mechanism underlying this action might involve increases in ALT, AST, GGT, ALP, TBil, and DBil and upregulation of MRP2 and RXRα mRNA and protein levels.

Paradoxical Effects of Emodin on ANIT-Induced Intrahepatic Cholestasis and Herb-Induced Hepatotoxicity in Mice.

Emodin is an active ingredient in many herbal medicines and has a broad spectrum of pharmacological activities. The current data indicate that emodin exerts its beneficial effect on alpha-naphthylisothiocyanate (ANIT)-induced intrahepatic cholestasis through its anti-oxidant and anti-inflammatory activities. Emodin has little effect on the concentrations of bile acids (BAs) in livers of ANIT-treated mice. Instead, emodin shows a potential pro-cholestatic effect by interfering with the crosstalk between AMP-activated protein kinase (AMPK) and farnesoid X receptor (Fxr) in the liver, which leads to a suppression of bile salt export pump (Bsep). Two emodin-containing herbs, namely Polygonum multiflorum (PM) and Semen cassiae (SC), markedly aggravate the intrahepatic cholestasis in ANIT-treated mice. SC interferes with the AMPK-Fxr crosstalk and suppresses Bsep in livers of mice. ANIT markedly increases the hepatic retention of emodin in SC-treated mice. The major SC constituents, in particular three anthraquinones, are able to activate AMPK in HepG2 cells and inhibit Bsep in primary mouse hepatocytes, with emodin showing the strongest activities. Together, the present study identifies a potential pro-cholestatic role of emodin in the hepatotoxicity of herbs.

Paeoniflorin attenuates ANIT-induced cholestasis by inhibiting apoptosis in vivo via mitochondria-dependent pathway.

Apoptosis induced by the bile acids in the liver is considered to play a pivotal role in the pathogenesis of cholestatic disease. Increasing evidence has demonstrated that Paeoniflorin (PF) exerts therapeutic effect on severe cholestatic liver diseases. However, whether PF could protect against alpha-naphthylisothiocyanate (ANIT)-induced cholestasis by inhibiting apoptosis remains unclear. In this study, we mainly investigated the effect and anti-apoptosis mechanism of PF on cholestasis. Experimental results indicated that PF pretreatment could attenuate liver damage and cholestasis by ANIT in rats, lift the biliary excretion in addition to decrease serum indices (ALT, AST, DBIL, TBIL, TBA, ALP and ϒ-GT) and conspicuous neutrophil infiltration and cell apoptosis in liver evidenced by TUNEL staining. Furthermore, the pro-apoptosis genes expression of Bax, Caspase-9 and Caspase-3 increased by ANIT were prominently reduced after PF treatment. The increase of anti-apoptosis gene and main regulator Bcl-2 in mitochondria by ANIT was largely reversed by PF pre-treatment. In summary, our study demonstrated that PF pre-treatment not only significantly attenuated ANIT-induced cholestasis and liver injury, but also largely reduced cell apoptosis in liver, thus may act as a potential therapeutic agent for cholestasis disease.

Attenuation of alpha-naphthylisothiocyanate (ANIT)-induced biliary fibrosis by depletion of hepatic macrophages in rats.

Biliary fibrosis is a complex process in which macrophages and myofibroblasts may play central roles. We investigated biliary fibrosis lesions induced in the Glisson's sheath in rats by alpha-naphthylisothiocyanate (ANIT) administration under macrophage depletion. Hepatic macrophages were depleted in F344 rats with liposome-encapsulated clodronate (CLD) (10mL/kg body weight, i.v) followed by bile duct injury with ANIT (75mg/kg body weight, i.p) (ANIT+CLD group). Rats received empty-liposomes (Lipo) followed by ANIT, and served as control (ANIT+Lipo group). In both ANIT+Lipo and ANIT+CLD groups, ANIT-induced bile duct injury with inflammatory cell infiltration was seen on days 1-3, and subsequently reparative fibrosis occurred on days 5 and 7. In comparisons between the two groups, macrophages reacting to CD68, CD163, MHC class II and CD204 were less in numbers in ANIT+CLD group; the most sensitive immunophenotype was of CD163-positive. Furthermore, in ANIT+CLD group interstitial mesenchymal cells/myofibroblasts reacting to vimentin, desmin and α-smooth muscle actin were also less in grades and tended to be delayed in appearance. Interestingly, MCP-1, IFN-γ, IL-10, and TGF-ß1 mRNAs were significantly increased mainly on day 2 in ANIT+Lipo group, while the levels of these factors were prominently lower in ANIT+CLD group. Collectively, depletion of hepatic macrophages plays roles in attenuating biliary fibrogenesis by production of inflammatory factors. The present results indicated clearly importance of macrophage functions in the pathogenesis of biliary fibrosis.

Protective effects of petroleum ether extracts of Herpetospermum caudigerum against α-naphthylisothiocyanate-induced acute cholestasis of rats.

ETHNOPHARMACOLOGICAL RELEVANCE: The ripe seeds of Herpetospermum caudigerum have been used in Tibetan folk medicine for treatment of bile or liver diseases including jaundice, hepatitis, intumescences or inflammation. Previously reports suggested that the seed oil and some lignans from H. caudigerum exhibited protective effects against carbon tetrachloride (CCl4)-induced hepatic damage in rats, which may be related to their free radical scavenging effect. However, the protective effect of H. caudigerum against cholestasis is still not revealed. The aim of the present study was to investigate the pharmacological effect and the chemical constituents of the petroleum ether extract (PEE) derived from H. caudigerum against α-naphthylisothiocyanate (ANIT)-induced acute cholestasis in rats. MATERIALS AND METHODS: Male cholestatic Sprague-Dawley (SD) rats induced by ANIT (60mg/kg) were orally administered with PEE (350, 700 and 1400mg/kg). Levels of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), γ-Glutamyl transpeptidase (γ-GTP), total bilirubin (TBIL), direct bilirubin (DBIL) and total bile acid (TBA), as well as bile flow, and histopathological assay were evaluated. Hepatic malondialdehyde (MDA), myeloperoxidase (MPO), superoxide dismutase (SOD), glutathione S-transferase (GST), and nitric monoxide (NO) in liver were measured to explore the possible protective mechanisms. Phytochemical analysis of PEE was performed by gas chromatography-mass spectrometer (GC-MS). RESULTS: PEE have exhibited significant and dose-dependent protective effect on ANIT-induced liver injury by reduce the increases in serum levels of ALT, AST, ALP, γ-GTP, TBIL, DBIL and TBA, restore the bile flow in cholestatic rats, and reduce the severity of the pathological tissue damage induced by ANIT. Hepatic MDA, MPO and NO contents in liver tissue were reduced, while SOD and GST activities were elevated in liver tissue. 49 compounds were detected and 39 of them were identified by GC-MS analysis, in which long-chain fatty acids were the main constituents. CONCLUSIONS: PEE exhibited a dose-dependently protective effect on ANIT-induced liver injury in cholestatic rats with the potential mechanism of attenuated oxidative stress in the liver tissue, and the possible active compounds were long-chain fatty acids.

Validation of precision-cut liver slices to study drug-induced cholestasis: a transcriptomics approach.

Hepatotoxicity is one of the major reasons for withdrawal of drugs from the market. Therefore, there is a need to screen new drugs for hepatotoxicity in humans at an earlier stage. The aim of this study was to validate human precision-cut liver slices (PCLS) as an ex vivo model to predict drug-induced cholestasis and identify the possible mechanisms of cholestasis-induced toxicity using gene expression profiles. Five hepatotoxicants, which are known to induce cholestasis (alpha-naphthyl isothiocyanate, chlorpromazine, cyclosporine, ethinyl estradiol and methyl testosterone) were used at concentrations inducing low (<30 %) and medium (30-50 %) toxicity, based on ATP content. Human PCLS were incubated with the drugs in the presence of a non-toxic concentration (60 µM) of a bile acid mixture (portal vein concentration and composition) as model for bile acid-induced cholestasis. Regulated genes include bile acid transporters and cholesterol transporters. Pathway analysis revealed that hepatic cholestasis was among the top ten regulated pathways, and signaling pathways such as farnesoid X receptor- and liver X receptor-mediated responses, which are known to play a role in cholestasis, were significantly affected by all cholestatic compounds. Other significantly affected pathways include unfolded protein response and protein ubiquitination implicating the role of endoplasmic reticulum stress. This study shows that human PCLS incubated in the presence of a physiological bile acid mixture correctly reflect the pathways affected in drug-induced cholestasis in the human liver. In the future, this human PCLS model can be used to identify cholestatic adverse drug reactions of new chemical entities.

Role of the lipid-regulated NF-κB/IL-6/STAT3 axis in alpha-naphthyl isothiocyanate-induced liver injury.

Alpha-naphthyl isothiocyanate (ANIT)-induced liver damage is regarded as a useful model to study drug-induced cholestatic hepatitis. Ultra-performance liquid chromatography coupled with electrospray ionization quadrupole mass spectrometry (UPLC-ESI-QTOF MS)-based metabolomics revealed clues to the mechanism of ANIT-induced liver injury, which facilitates the elucidation of drug-induced liver toxicity. 1-Stearoyl-2-hydroxy-sn-glycero-3-phosphocholine (LPC 18:0) and 1-oleoyl-2-hydroxy-sn-glycero-3-phosphocholine (LPC 18:1) were significantly increased in serum from ANIT-treated mice, and this increase resulted from altered expression of genes encoding the lipid metabolism enzymes Chka and Scd1. ANIT also increased NF-κB/IL-6/STAT3 signaling, and in vitro luciferase reporter gene assays revealed that LPC 18:0 and LPC 18:1 can activate NF-κB in a concentration-dependent manner. Activation of PPARα through feeding mice a Wy-14,643-containing diet (0.1%) reduced ANIT-induced liver injury, as indicated by lowered ALT and AST levels, and liver histology. In conclusion, the present study demonstrated a role for the lipid-regulated NF-κB/IL-6/STAT3 axis in ANIT-induced hepatotoxicity, and that PPARα may be a potential therapeutic target for the prevention of drug-induced cholestatic liver injury.