Baicalin Ameliorates Experimental Liver Cholestasis in Mice by Modulation of Oxidative Stress, Inflammation, and NRF2 Transcription Factor

Therapeutic approaches for cholestatic liver diseases: the role of nitric oxide pathway

Cholestasis describes bile secretion or flow impairment, which is clinically manifested with fatigue, pruritus, and jaundice. Neutrophils play a crucial role in many diseases such as cholestasis liver diseases through mediating several oxidative and inflammatory pathways. Data have been collected from clinical, in vitro, and in vivo studies published between 2000 and December 2021 in English and obtained from the PubMed, Google Scholar, Scopus, and Cochrane libraries. Although nitric oxide plays an important role in the pathogenesis of cholestatic liver diseases, excessive levels of NO in serum and affected tissues, mainly synthesized by the inducible nitric oxide synthase (iNOS) enzyme, can exacerbate inflammation. NO induces the inflammatory and oxidative processes, which finally leads to cell damage. We found that natural products such as baicalin, curcumin, resveratrol, and lycopene, as well as chemical likes ursodeoxycholic acid, dexamethasone, rosuvastatin, melatonin, and sildenafil, are able to markedly attenuate the NO production and iNOS expression, mainly through inducing the nuclear factor κB (NF-κB), Janus kinase and signal transducer and activator of transcription (JAK/STAT), and toll like receptor-4 (TLR4) signaling pathways. This study summarizes the latest scientific data about the bile acid signaling pathway, the neutrophil chemotaxis recruitment process during cholestasis, and the role of NO in cholestasis liver diseases. Literature review directed us to propose that suppression of NO and its related pathways could be a therapeutic option for preventing or treating cholestatic liver diseases.

Genistein stimulates the viability and prevents myofibroblastic transformation in human trabecular meshwork cells stimulated by TGF-β

Primary open-angle glaucoma (POAG) is the most common type of glaucoma leading to blindness. The search for ways to prevent/treat this entity is one of the main challenges of today's ophthalmology. One of such solution seems to be biologically active substances of natural origin, such as genistein (GEN), which can affect the function of isolated trabecular meshwork by the inhibition of protein tyrosine kinase. However, the role of GEN in viability as well as myofibroblastic transformation in human trabecular meshwork cells stimulated by TGF-β is unknown. Using human trabecular meshwork cells (HTMCs) we investigated the effect of genistein on cell viability and myofibroblastic transformation stimulated by TGF-β1 and TGF-β2. Using Real-Time PCR, western blot and immunofluorescence we determined the effect on the expression changes of αSMA, TIMP1, collagen 1 and 3 at mRNA and protein level. We found that genistein increases the viability of HTMCs (1, 2, 3 μg/ml; P < 0.05 and 4, 5, 10, 15, 20 μg/ml; P < 0.01). Moreover, we found that addition of 10, 15 and 20 μg/ml is able to prevent myofibroblastic transformation of HTMCs by decreasing αSMA, TIMP1, collagen 1 and 3 mRNA and protein expression (P < 0.01). Based on the obtained results, we can conclude that genistein is a potential factor that can prevent the myofibroblastic transformation of HTMCs accompanying glaucoma. Describing GEN influence on myofibroblastic transformation processes in HTMC allows us to conclude that it can be considered a potential therapeutic agent or a substance supporting treatment in patients with glaucoma.

Protective Effect of Baicalin on Chlorpyrifos-Induced Liver Injury and Its Mechanism

Chlorpyrifos (CPF) plays a vital role in the control of various pests in agriculture and household life, even though some studies have indicated that CPF residues pose a significant risk to human health. Baicalin (BA) is a flavonoid drug with an obvious effect on the prevention and treatment of liver diseases. In this study, the protective effect of BA in vitro and in vivo was investigated by establishing a CPF-induced AML12 cell damage model and a CPF-induced Kunming female mouse liver injury model. The AML12 cell damage model indicated that BA had a good positive regulatory effect on various inflammatory factors, redox indexes, and abnormal apoptosis factors induced by CPF. The liver injury model of female mice in Kunming showed that BA significantly improved the liver function indexes, inflammatory response, and fibrosis of mice. In addition, BA alleviated CPF-induced AML12 cell damage and Kunming female mouse liver injury by enhancing autophagy and regulating apoptosis pathways through Western blotting. Collectively, these data suggest that the potential mechanism of BA is a multi-target and multi-channel treatment for chlorpyrifos-induced liver injury.

Hypericum perforatum L. and the Underlying Molecular Mechanisms for Its Choleretic, Cholagogue, and Regenerative Properties

Any defects in bile formation, secretion, or flow may give rise to cholestasis, liver fibrosis, cirrhosis, and hepatocellular carcinoma. As the pathogenesis of hepatic disorders is multifactorial, targeting parallel pathways potentially increases the outcome of therapy. Hypericum perforatum has been famed for its anti-depressive effects. However, according to traditional Persian medicine, it helps with jaundice and acts as a choleretic medication. Here, we will discuss the underlying molecular mechanisms of Hypericum for its use in hepatobiliary disorders. Differentially expressed genes retrieved from microarray data analysis upon treatment with safe doses of Hypericum extract and intersection with the genes involved in cholestasis are identified. Target genes are located mainly at the endomembrane system with integrin-binding ability. Activation of α5β1 integrins, as osmo-sensors in the liver, activates a non-receptor tyrosine kinase, c-SRC, which leads to the insertion of bile acid transporters into the canalicular membrane to trigger choleresis. Hypericum upregulates CDK6 that controls cell proliferation, compensating for the bile acid damage to hepatocytes. It induces ICAM1 to stimulate liver regeneration and regulates nischarin, a hepatoprotective receptor. The extract targets the expression of conserved oligomeric Golgi (COG) and facilitates the movement of bile acids toward the canalicular membrane via Golgi-derived vesicles. In addition, Hypericum induces SCP2, an intracellular cholesterol transporter, to maintain cholesterol homeostasis. We have also provided a comprehensive view of the target genes affected by Hypericum's main metabolites, such as hypericin, hyperforin, quercitrin, isoquercitrin, quercetin, kaempferol, rutin, and p-coumaric acid to enlighten a new scope in the management of chronic liver disorders. Altogether, standard trials using Hypericum as a neo-adjuvant or second-line therapy in ursodeoxycholic-acid-non-responder patients define the future trajectories of cholestasis treatment with this product.

γ-Mangostin abrogates AINT-induced cholestatic liver injury: Impact on Nrf2/NF-κB/NLRP3/Caspase-1/IL-1β/GSDMD signalling

γ-Mangostin (γ-MN) is one of the abundant xanthones separated from Garcinia mangostana (Clusiaceae) pericarps that has been reported to have varied bioactivities such as neuroprotective, cytotoxic, antihyperglycemic, antioxidant, and anti-inflammation. Yet, its effect on cholestatic liver damage (CLI) has not been investigated. This study explored the protective activity of γ-MN against alpha-naphthyl isothiocyanate (ANIT)-induced CLI in mice. The results showed that γ-MN protected against ANIT-induced CLI as indicated by reduced serum levels of hepatic injury parameters (e.g., ALT, AST, γ-GT, ALP, LDH, bilirubin, and total bile acids). ANIT-induced pathological lesions were improved in γ-MN pre-treated groups. γ-MN exerted potent antioxidant effects as it lowered the parameters of lipid peroxidation (4-HNE, PC, and MDA) and intensified the content and activity of antioxidants (TAC, GSH, GSH-Px, GST, and SOD) in the hepatic tissue. Furthermore, γ-MN enhanced the signalling of Nrf2/HO-1 as it augmented the mRNA expression of Nrf2/downstream genes (HO-1/GCLc/NQO1/SOD). The binding capacity and the immuno-expression of Nrf2 were also increased. γ-MN showed anti-inflammatory capacity as it suppressed the activation of NF-κB signalling, it decreased mRNA expression and levels of NF-κB/TNF-α/IL-6 and the immuno-expression of NF-κB/TNF-α. In addition, γ-MN inhibited the activation of NLRP3 inflammasome as it lowered the mRNA expression of NLRP3/caspase-1/IL-1β along with their levels as well as the immuno-expression of caspase-1/IL-1β. γ-MN also reduced the level of the pyroptotic parameter GSDMD. Collectively, this study demonstrated the potent hepatoprotective potential of γ-MN against CLI which was linked to its ability to potentiate Nrf2/HO-1 and to offset NF-κB/NLRP3/Caspase-1/IL-1β/GSDMD. Hence, γ-MN may be suggested as a new candidate for cholestatic patients.

Oliveria decumbens Extract Exhibits Hepatoprotective Effects Against Bile Duct Ligation-Induced Liver Injury in Rats by Reducing Oxidative Stress

Background: Cholestasis is described as a disease in which bile flow from the liver is reduced or stopped, and due to its oxidative effects, irreversible consequences may occur. Due to the remarkable antioxidant properties of Oliveria decumbens (OD) and the contribution of oxidants to the progression of bile duct ligation (BDL)-induced cholestasis, Objectives: This research aimed to examine how the OD ethanolic extract affected liver damage and oxidant-antioxidant balance markers in BDL-induced cholestasis. Methods: Forty male Wistar rats weighing 200 - 250 g were used. Cholestasis was induced using the BDL approach. The rats were categorized into four groups: Group 1, sham control (SC); group 2, cholestatic; group 3, SC + OD; and group 4, cholestatic + OD. A dose of OD ethanolic extract was administered orally (500 mg/kg/day) to rats for seven days. Seven days following surgery, the rats’ blood samples were collected; after sacrifice, a part of the liver tissue was isolated. A histopathological examination was performed, while the rest was stored at -70°C in liquid nitrogen. Heparin-containing tubes were used to gather blood samples. In plasma and hepatic tissue, biochemical tests, histopathological evaluations, and oxidative stress markers staining levels were performed. Results: Our findings showed that OD could effectively reduce liver injury by reducing the activity of liver function enzymes (AST and ALP). At the same time, it did not affect total bilirubin and protein. Bile duct ligation-induced hepatic markers of protein oxidation (PCO) and reactive nitrogen species (NO) were significantly decreased by OD, and it also promoted liver antioxidant capacity by enhancing superoxide dismutase (SOD) activities. Moreover, OD treatment prevented liver bile duct proliferative changes in histopathologic analysis. Conclusions: Our study confirmed that OD exerts substantial hepatoprotective activities against BDL-induced cholestasis by improving liver damage markers and regulating oxidative stress. It may be a beneficial therapeutic agent for managing cholestasis. Bioassay-guided isolation and identification of bioactive OD secondary metabolites can further direct the discovery of potential natural-based drug candidates.

Exploration of the potential mechanism of Baicalin for hepatic fibrosis based on network pharmacology, gut microbiota, and experimental validation

Baicalin (BA) is among the most effective and abundant flavonoids extracted from Scutellaria baicalensis that may be utilized to treat diseases associated with hepatic fibrosis (HF). Through network pharmacology, gut microbiota, and experimental validation, this research intends to elucidate the multi-target mechanism of BA on HF. BA targets were screened using databases and literature. As a result, In the anti-HF mechanism, the BA and 191 HF-associated targets interact, with 9 specific targets indicating that the BA's anti-HF mechanism is closely linked to gut microbiota. Consequently, rat intestinal content samples were obtained and examined using 16S rRNA sequencing. In the BA-treated group, the gut microbiota was positively regulated at the phylum,and genus levels, with Lactobacillus performing significantly. The study concluded that BA has a multi-targeted anti-HF effect and has changed the gut microbial ecosystem.

Fluvoxamine ameliorates oxidative stress and inflammation induced by bile-duct ligation in male rats

Introduction

Cholestasis is a disorder that the bile ducts were narrowed and bile acids are not released simply. Bile acids-induced liver damage is exacerbated by inflammation and oxidative stress. The goal of the current study was to investigate the protective impacts of fluvoxamine (Flu) on oxidant-antioxidant balance and inflammatory cytokines in the bile duct ligated (BDL) rats.

Methods

Thirty-two male rats were arbitrarily allocated in 4 groups; sham-control (SC), SC+ 150 mg/kg Flu (SCF), bile duct ligation (BDL), and BDL+ 150 mg/kg Flu (BDLF). The rats received distilled water and Flu orally for one week. Biochemical analysis, hematoxylin and eosin staining, as well as oxidant/antioxidant status were evaluated. Also, the mRNA expression of TGF-β1, IL-1, TNF-α, and α-SMA were determined.

Results

The findings indicated serum values of ALT, total bilirubin, and ALP slightly declined in the BDL + Flu group in contrast to BDL rats. The plasma protein carbonyl and inflammatory markers were markedly increased in the BDL group in contrast with SC group (P ≤ 0.05). Treatment with Flu in BDL rats markedly reduced the values of hepatic nitric oxide metabolite and malondialdehyde, plasma protein carbonyl, as well as TNF-α mRNA level (P ≤ 0.05). Histological parameters were improved in the BDL + Flu group in comparison to BDL merely rats.

Conclusion

It seems that Flu declined oxidative stress probably by inhibiting lipid peroxidation, protein oxidation, and nitric oxide formation. Also, it reduced inflammation by decreasing TNF-α mRNA expression.

Role of baicalin as a potential therapeutic agent in hepatobiliary and gastrointestinal disorders: A review

Baicalin is a natural bioactive compound derived from Scutellaria baicalensis, which is extensively used in traditional Chinese medicine. A literature survey demonstrated the broad spectrum of health benefits of baicalin such as antioxidant, anticancer, anti-inflammatory, antimicrobial, cardio-protective, hepatoprotective, renal protective, and neuroprotective properties. Baicalin is hydrolyzed to its metabolite baicalein by the action of gut microbiota, which is further reconverted to baicalin via phase 2 metabolism in the liver. Many studies have suggested that baicalin exhibits therapeutic potential against several types of hepatic disorders including hepatic fibrosis, xenobiotic-induced liver injury, fatty liver disease, viral hepatitis, cholestasis, ulcerative colitis, hepatocellular and colorectal cancer. During in vitro and in vivo examinations, it has been observed that baicalin showed a protective role against liver and gut-associated abnormalities by modifying several signaling pathways such as nuclear factor-kappa B, transforming growth factor beta 1/SMAD3, sirtuin 1, p38/mitogen-activated protein kinase/Janus kinase, and calcium/calmodulin-dependent protein kinase kinaseβ/adenosine monophosphate-activated protein kinase/acetyl-coenzyme A carboxylase pathways. Furthermore, baicalin also regulates the expression of fibrotic genes such as smooth muscle actin, connective tissue growth factor, β-catenin, and inflammatory cytokines such as interferon gamma, interleukin-6 (IL-6), tumor necrosis factor-alpha, and IL-1β, and attenuates the production of apoptotic proteins such as caspase-3, caspase-9 and B-cell lymphoma 2. However, due to its low solubility and poor bioavailability, widespread therapeutic applications of baicalin still remain a challenge. This review summarized the hepatic and gastrointestinal protective attributes of baicalin with an emphasis on the molecular mechanisms that regulate the interaction of baicalin with the gut microbiota.

Plumbagin ameliorates bile duct ligation-induced cholestatic liver injury in rats

Plumbagin, a natural bicyclic naphthoquinone, has diverse pharmacological properties and biological benefits against a number of disorders, including liver disease. Though plumbagin's hepatoprotective potential attracts attention, currently no experimental evidence exists on its effectiveness against cholestatic liver injury. The present study investigated its hepatoprotection in the rat model of extrahepatic cholestasis using Bile Duct Ligation (BDL). We found that daily plumbagin supplementation protected the liver from cholestatic damage. Hepatoprotective actions of plumbagin were accompanied by reduction of Transforming Growth Factor β1 (TGF-β1)/Smad, High Mobility Group Box-1 (HMGB1)/Toll-Like Receptor-4 (TLR4), Hypoxia-Inducible Factor-1α (HIF-1α), Aryl Hydrocarbon Receptor (AhR), Heat Shock Protein 90 (HSP90), caveolin-1, NF-κB/AP-1, Dynamin Related Protein-1 (Drp1), malondialdehyde level, Interleukin-1β (IL-1β), p62/SQSTM1, and caspase 3 as well as increase of Farnesoid X Receptor (FXR), bile acid efflux transporters, glutathione, LC3-II, Beclin1, and nuclear NF-E2-Related Factor-2 (Nrf2) and Transcription Factor EB (TFEB). The activation of nuclear Nrf2 caused by plumbagin correlated well with the improvement in bile acid retention, liver histology, serum biochemical, ductular reaction, mitochondrial dysfunction, oxidative stress, inflammation, apoptosis, impaired autophagy, and fibrosis, involving interplay of multiple intracellular signaling pathways. Plumbagin is likely a candidate drug to protect the liver from cholestatic damages. Despite the promising findings from this study, translational implication of plumbagin on cholestatic liver injury warrants further investigation.

Postnatal baicalin ameliorates behavioral and neurochemical alterations in valproic acid-induced rodent model of autism: The possible implication of sirtuin-1/mitofusin-2/ Bcl-2 pathway

Autism spectrum disorder (ASD) is characterized by pervasive impairments in social communication along with repetitive or stereotyped behaviors. Although its distinctive etiology isn`t completely understood, genetic and environmental risk factors were incriminated. Being a flavonoid of high biomedical value, baicalin was recently verified as an emerging medicinal herb with numerous pharmacological activities. The objective of this study was to investigate the feasible effects of baicalin on valproic acid (VPA)-induced autism regarding its potential mitochondrial modulatory, antioxidant, and antiapoptotic effects. The present study was performed using a rodent model of autism by exposing rat fetuses to VPA on the 12.5th day of gestation. Ten male Wistar rats that were born from control pregnant females were considered as group I (control group). Twenty male Wistar rats that were born from prenatal VPA- treated females were further divided into two groups: Group II (VPA- induced ASD) and group III (VPA + Baicalin). Postnatal baicalin promoted postnatal growth and maturation. In addition, it improved motor development and ameliorated repetitive behavior as well as social deficits in prenatally exposed VPA rats. Moreover, baicalin enhanced neuronal mitochondrial functions as evidenced by elevation of mitochondrial adenosine triphosphate (ATP) level and promotion of mitofusin-2 expression. Furthermore, baicalin elevated sirtuin-1 (SIRT1) level in VPA rats' brain tissues and restored the antioxidant defense mechanisms. Besides, it abrogated the neuronal histopathological changes in the brain tissues. Based on the data herein, baicalin may provide a promising pre-clinical therapeutic line in ASD as a mitochondrial function modulator, antioxidant and anti-apoptotic agent.

18β-Glycyrrhetinic Acid Protects against Cholestatic Liver Injury in Bile Duct-Ligated Rats

18β-Glycyrrhetinic acid is a nutraceutical agent with promising hepatoprotective effects. Its protective mechanisms against cholestatic liver injury were further investigated in a rodent model of extrahepatic cholestasis caused by Bile Duct Ligation (BDL) in rats. The daily oral administration of 18β-Glycyrrhetinic acid improved liver histology, serum biochemicals, ductular reaction, oxidative stress, inflammation, apoptosis, impaired autophagy, and fibrosis. 18β-Glycyrrhetinic acid alleviated the BDL-induced hepatic and systemic retention of bile acids, matrix-producing cell activation, hepatic collagen deposition, Transforming Growth Factor beta-1/Smad activation, malondialdehyde elevation, glutathione reduction, High Mobility Group Box-1/Toll-Like Receptor-4 activation, NF-κB activation, inflammatory cell infiltration/accumulation, Interleukin-1β expression, Signal Transducer and Activator of Transcription-1 activation, Endoplasmic Reticulum stress, impairment autophagy, and caspase 3 activation. Conversely, the protein expression of Sirt1, Farnesoid X Receptor, nuclear NF-E2-Related Factor-2, Transcription Factor EB, bile acid efflux transporters, and LC3-II, as well as the protein phosphorylation of AMP-Activated Protein Kinase, was promoted in 18β-Glycyrrhetinic acid-treated BDL rats. The hepatoprotective effects of 18β-Glycyrrhetinic acid in the present investigation correlated well with co-activation and possible interactions among Sirt, FXR, and Nrf2. The concurrent or concomitant activation of Sirt1, FXR, and Nrf2 not only restored the homeostatic regulation of bile acid metabolism, but also alleviated oxidative stress, inflammation, apoptosis, impaired autophagy, and fibrosis.

Hepatoprotective effect of Baicalin against thioacetamide-induced cirrhosis in rats: Targeting NOX4/NF-κB/NLRP3 inflammasome signaling pathways

Aim Liver cirrhosis is the result of a vicious cycle of both chronic oxidative stress and inflammation. NADPH oxidase-4 (NOX4) and its companion, NOD-like receptor protein 3 (NLRP3) inflammasome, are emerging as therapeutic targets of liver fibrosis.

MAIN METHODS

Baicalin (BA), a natural flavone, has been investigated for its therapeutic potential against cirrhosis induced by thioacetamide (TAA) (200 mg/kg, twice/week) for 12 weeks in Sprague-Dawley rats. Two doses of BA were administered (25 and 75 mg/kg/day, orally, a week after TAA was stopped and continued for 4 weeks).

KEY FINDINGS

BA was able to reduce fibrosis visualized by Masson trichrome and immunohistochemical staining of the hepatic α-smooth muscle actin (α-SMA) and transforming growth factor-β1. Moreover, BA was able to ameliorate inflammation by reducing hepatic NLRP3 inflammasome subunits, NLRP3 and caspase-1, both parts of the complex responsible for the activation of different interleukins (IL), measured as IL-1β. In addition, BA was able to reduce hepatic nuclear factor kappa B (NF-κB)-driven inflammation through IL-6. BA targeted inflammation through its anti-oxidant ability evidenced by the enhancement of the hepatic superoxide dismutase (SOD) and reduced glutathione (GSH) activity and level, respectively, and the reduction of both hepatic malondialdehyde (MDA) and nitric oxide (NOx) contents. Treatment with BA significantly decreased TAA-induced elevation in hepatic NOX4, a key enzyme for reactive oxygen species (ROS) generation, as well as, inducible nitric oxide synthase (iNOS).

SIGNIFICANCE

therefore, the study could conclude, the anti-fibrotic effect of BA through TGF- β1/NOX4/NF-κB/NLRP3 pathway, exerting both anti-inflammatory and anti-oxidant effects.

Protective effect of baicalin against arsenic trioxide-induced acute hepatic injury in mice through JAK2/STAT3 signaling pathway

Baicalin (BA) is a kind of flavonoid that is isolated from Scutellaria baicalensis Georgi, which has been verified to have hepatoprotective effects in some diseases. However, the role of BA in acute hepatic injury induced by arsenic trioxide (ATO) remains unclear. The aim of this study was to investigate the protective action of BA on acute hepatic injury induced by ATO and to probe its possible mechanism. Mice were pretreated with BA (50, 100 mg/kg) by gavage. After 7 h, ATO (7.5 mg/kg) was injected intraperitoneally to induce liver injury. After 7 days of treatment, serum and hepatic specimens were collected and assayed to evaluate the hepatoprotective effect of BA. Pathological sections and the liver function index indicated that ATO caused significant liver injury. The fluorescence of reactive oxygen species and oxidative stress indicators showed that ATO also increased oxidative stress. The inflammatory markers in ATO-induced mice also increased significantly. Staining of the terminal deoxynucleotidyl transferase dUTP nick end labeling and apoptotic factor assay showed that apoptosis increased. However, with BA pretreatment, these changes were significantly weakened. In addition, BA treatment promoted the expression of proteins related to the JAK2/STAT3 signaling pathway. The results suggest that BA can ameliorate acute ATO-induced hepatic injury in mice, which is related to the inhibition of oxidative stress, thereby reducing inflammation and apoptosis. The mechanism of this protection is potentially related to the JAK2/STAT3 signaling pathway.

Advances of natural activators for Nrf2 signaling pathway on cholestatic liver injury protection: a review

Cholestasis is a common manifestation of obstruction of bile flow in various liver diseases. If the bile acid accumulation is not treated in time, it will further lead to hepatocyte damage, liver fibrosis and ultimately to cirrhosis, which seriously affects human life. The pathogenesis of cholestatic liver injury is very complicated, mainly including oxidative stress and inflammation. Nuclear factor erythroid 2-related factor 2 (Nrf2) is an important transcription factor responsible for upregulating expression of various genes with cytoprotective functions. Nrf2 activation has been proved to inhibit oxidative stress and inflammatory reaction, modulate bile acid homeostasis, and alleviate fibrosis during cholestasis. Therefore, Nrf2 emerges as a potential therapeutic target for cholestatic liver injury. In recent years, natural products with various biological activities including anti-inflammatory, anti-oxidant, anti-tumor and anti-fibrotic effects have received growing attention for being hepatoprotective agents. Natural products like asiatic acid, diosmin, rutin, and so forth have shown significant potential in activating Nrf2 pathway which can lead to attenuate cholestatic liver injury. Therefore, this paper emphasizes the effect of Nrf2 signaling pathway on alleviating cholestasis, and summarizes recent evidence about natural Nrf2 activators with hepatoprotective effect in various models of cholestatic liver injury, thus providing theoretical reference for the development of anti-cholestatic drug.

Baicalin alleviates Mycoplasma gallisepticum-induced oxidative stress and inflammation via modulating NLRP3 inflammasome-autophagy pathway

Baicalin is a well-known flavonoid compound, possess therapeutic potential against inflammatory diseases. Previous studies reported that Mycoplasma gallisepticum (MG) induced inflammatory response and immune dysregulation inside the host body. However, the underlying molecular mechanisms of baicalin against MG-infected chicken-like macrophages (HD11 cells) are still illusive. Oxidant status and total reactive oxygen species (ROS) were detected by ELISA assays and flow cytometry respectively. Mitochondrial membrane potential (ΔΨ_M) was evaluated by immunofluorescence microscopy. Transmission electron microscopy was used for ultrastructural analysis. The hallmarks of inflammation and autophagy were determined by western blotting. Oxidative stress and reactive oxygen species (ROS) were significantly enhanced in the MG-infected HD11 cells. MG infection caused disruption in the mitochondrial membrane potential (ΔΨ_M) compared to the control conditions. Meanwhile, baicalin treatment reduced MG-induced reactive oxygen species (ROS), oxidative stress and alleviated the disruption in ΔΨ_M. The activities of inflammatory markers were significantly enhanced in the MG-infected HD11 cells. Increased protein expressions of TLR-2-NF-κB pathway, NLRP3-inflammasome and autophagy-related proteins were detected in the MG-infected HD11 cells. Besides, baicalin treatment significantly reduced the protein expressions of TLR-2-NF-κB pathway and NLRP3 inflammasome. While, the autophagy-related proteins were significantly enhanced with baicalin treatment in a dose-dependent manner in the MG-infected HD11 cells. The results showed that baicalin prevented HD11 cells from MG-induced oxidative stress and inflammation via the opposite modulation of TLR-2-NF-κB-mediated NLRP3-inflammasome pathway and autophagy, and baicalin could be a promising candidate for the prevention of inflammatory effects caused by MG-infection in macrophages.

Development and verification of a risk prediction model for bronchopulmonary dysplasia in very low birth weight infants

BACKGROUND

To analyze the risk factors of bronchopulmonary dysplasia (BPD) of very low birth weight infants (VLBWIs), and to develop and verify a risk prediction model of BPD.

METHODS

The data of 611 VLBWIs from the neonatal intensive care unit (NICU) of a tertiary grade A hospital in Suzhou from January 2017 to September 2019 were collected. The data was randomly divided into the modeling set (451 cases) and the validation set (160 cases). Binary logistic regression was used to analyze the data, and the model was examined by a receiver operating characteristic (ROC) curve. The grouped data was used to verify the sensitivity and specificity of the model.

RESULTS

The study found that neonatal asphyxia, the positive rate of sputum culture, neonatal sepsis, neonatal respiratory distress syndrome (NRDS), blood transfusions (≥3), patent ductus arteriosus (PDA), the time of invasive mechanical ventilation, the duration of oxygen therapy, and the time of parenteral nutrition were the independent risk factors of BPD, while 1 min Apgar score was a protective factor. The model formula was Z=neonatal asphyxia * 1.229 + the positive rate of sputum culture * 1.265 + neonatal sepsis * 1.677 + NRDS * 1.848 + blood transfusions (≥3) * 1.455 + PDA * 1.835 - 1 min Apgar score * 0.25 + the time of invasive mechanical ventilation * 0.123 + the duration of oxygen therapy * 0.09 + the time of parenteral nutrition * 0.057 - 8.077. The area under the ROC curve of this model was 0.965 (95% CI: 0.946-0.983), with a sensitivity of 93.7% and a specificity of 91.3%. Verification of this prediction model showed a sensitivity of 92.9% and a specificity of 76%, demonstrating that the effects of this model were satisfactory.

CONCLUSIONS

The risk prediction model had a good predictive effect for the risk of BPD in VLBWIs, and can provide a reference for preventive treatment and nursing intervention.

Bicyclol Alleviates Signs of BDL-Induced Cholestasis by Regulating Bile Acids and Autophagy-Mediated HMGB1/p62/Nrf2 Pathway

Cholestasis is a liver disease characterized by the accumulation of toxic bile salts, bilirubin, and cholesterol, resulting in hepatocellular damage. Recent findings have revealed several key steps of cholestasis liver injury including the toxicity of bile acids and accumulation of proinflammatory mediator. In this study, we investigated the protective effect of bicyclol in cholestasis caused by bile duct ligation (BDL), as well as relevant mechanisms. Bicyclol attenuated liver damage in BDL mice by increasing the levels of hydrophilic bile acid such as α-MCA and β-MCA, regulating bile acid-related pathways and improving histopathological indexes. High-mobility group box 1 (HMGB1) is an extracellular damage-associated molecular pattern molecule which can be used as biomarkers of cells and host defense. Bicyclol treatment decreased extracellular release of HMGB1. In addition, HMGB1 is also involved in regulating autophagy in response to oxidative stress. Bicyclol promoted the lipidation of LC3 (microtubule-associated protein 1 light chain 3)-Ⅱ to activate autophagy. The nuclear factor, E2-related factor 2 (Nrf2) and its antioxidant downstream genes were also activated. Our results indicate that bicyclol is a promising therapeutic strategy for cholestasis by regulating the bile acids and autophagy-mediated HMGB1/p62/Nrf2 pathway.

Pharmacological properties of baicalin on liver diseases: a narrative review

Baicalin is the main active component of Scutellaria baicalensis, widely used in traditional Chinese medicine thanks to its various pharmacological effects, such as anti-tumor, anti-inflammatory, and antibacterial properties, as well as cardiovascular, hepatic, and renal protective effect. Recently, the protective effects of baicalin on liver disease have received much more attention. Several studies showed that baicalin protects against several types of liver diseases including viral hepatitis, fatty liver disease, xenobiotic induced liver injury, cholestatic liver injury, and hepatocellular carcinoma, with a variety of pharmacological mechanisms. A comprehensive understanding of the mechanism of baicalin can provide a valuable reference for its clinical use, but up to now, no narrative review is available that summarizes the pharmacological effects of baicalin to clarify its potential use in the treatment of liver diseases. Therefore, this review summarizes the progress of baicalin research and the underlying mechanism in the treatment of various liver diseases, to promote further research and its clinical application.

Natural Aldose Reductase Inhibitor: A Potential Therapeutic Agent for Non-alcoholic Fatty Liver Disease

Aldose reductase (AR) has been reported to be involved in the development of nonalcoholic fatty liver disease (NAFLD). Hepatic AR is induced under hyperglycemia condition and converts excess glucose to lipogenic fructose, which contributes in part to the accumulation of fat in the liver cells of diabetes rodents. In addition, the hyperglycemia-induced AR or nutrition-induced AR causes suppression of the transcriptional activity of peroxisome proliferator-activated receptor (PPAR) α and reduced lipolysis in the liver, which also contribute to the development of NAFLD. Moreover, AR induction in non-alcoholic steatohepatitis (NASH) may aggravate oxidative stress and the expression of inflammatory cytokines in the liver. Here, we summarize the knowledge on AR inhibitors of plant origin and review the effect of some plant-derived AR inhibitors on NAFLD/NASH in rodents. Natural AR inhibitors may improve NAFLD at least in part through attenuating oxidative stress and inflammatory cytokine expression. Some of the natural AR inhibitors have been reported to attenuate hepatic steatosis through the regulation of PPARα-mediated fatty acid oxidation. In this review, we propose that the natural AR inhibitors are potential therapeutic agents for NAFLD.

Baicalin and the liver-gut system: Pharmacological bases explaining its therapeutic effects

With the development of high-throughput screening and bioinformatics technology, natural products with a range of pharmacological targets in multiple diseases have become important sources of new drug discovery. These compounds are derived from various plants, including the dried root of Scutellaria baicalensis Georgi, which is often used as a traditional Chinese herb named Huangqin, a popular medication used for thousands of years in China. Many studies have shown that baicalin, an extract from Scutellaria baicalensis Georgi, exerts various protective effects on liver and gut diseases. Baicalin plays a therapeutic role mainly by mediating downstream apoptosis and immune response pathways induced by upstream oxidative stress and inflammation. During oxidative stress regulation, PI3K/Akt/NRF2, Keap-1, NF-κB and HO-1 are key factors associated with the healing effects of baicalin on NAFLD/NASH, ulcerative colitis and cholestasis. In the inflammatory response, IL-6, IL-1β, TNF-α, MIP-2 and MIP-1α are involved in the alleviation of NAFLD/NASH, cholestasis and liver fibrosis by baicalin, as are TGF-β1/Smads, STAT3 and NF-κB. Regarding the apoptosis pathway, Bax, Bcl-2, Caspase-3 and Caspase-9 are key factors related to the suppression of hepatocellular carcinoma and attenuation of liver injury and colorectal cancer. In addition to immune regulation, PD-1/PDL-1 and TLR4-NF-κB are correlated with the alleviation of hepatocellular carcinoma, ulcerative colitis and colorectal cancer by baicalin. Moreover, baicalin regulates intestinal flora by promoting the production of SCFAs. Furthermore, BA is involved in the interactions of the liver-gut axis by regulating TGR5, FXR, bile acids and the microbiota. In general, a comprehensive analysis of this natural compound was conducted to determine the mechanism by which it regulates bile acid metabolism, the intestinal flora and related signaling pathways, providing new insights into the pharmacological effects of baicalin. The mechanism linking the liver and gut systems needs to be elucidated to draw attention to its great clinical importance.

Baicalin improves the survival in endotoxic mice and inhibits the inflammatory responses in LPS-treated RAW 264.7 macrophages

Introduction:

Sepsis is a severe disease with a high morbidity and mortality. Baicalin, an active compound of Chinese medicine, Scutellaria baicalensis Georgi (Huang Qui), exhibits several beneficial effects. In this study, we examined whether administration of baicalin increases the survival in mice with endotoxemia and investigated its anti-inflammatory mechanisms in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages.

Methods:

The production of NOx, PGE2, and pro-inflammatory cytokines, the mRNA and protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), and the nuclear translocation of NF-κB in LPS-stimulated macrophages or endotoxic mice were determined. The model of severe endotoxic mice was established by injection of LPS (60 mg/kg, i.p.).

Results:

Baicalin significantly inhibited the production of NO, PGE2, and pro-inflammatory cytokines, including TNF-α, IL-1β, and IL-6 in LPS-stimulated macrophages. Baicalin treatment also markedly suppressed LPS-induced iNOS and COX-2 expression at the transcriptional and translational levels, and the nuclear translocation of NF-κB in macrophages. Similarly, the serum concentrations of NOx, PGE2, and pro-inflammatory cytokines, and the lung myeloperoxidase activity were greatly reduced in baicalin-treated endotoxic mice. Notably, after LPS injection, the 3-day survival rate of mice treated with pre- or post-administration of baicalin (50 mg/kg, i.p.) remarkably increased to 100% and 90%, respectively compared with LPS-injected alone mice with a survival rate of 0%.

Conclusion:

Baicalin has a potent anti-inflammatory activity in LPS-stimulated macrophages and endotoxic mice. Moreover, treatment with baicalin dramatically increased the survival in the severe septic mice, suggesting that baicalin may be a potential agent for sepsis therapy.

Discovery and Development of Inflammatory Inhibitors from 2-Phenylchromonone (Flavone) Scaffolds

Flavonoids are compounds based on a 2-phenylchromonone scaffold. Flavonoids can be divided into flavonoids, flavonols, dihydroflavones, anthocyanins, chalcones and diflavones according to the oxidation degree of the central tricarbonyl chain, the connection position of B-ring (2-or 3-position), and whether the tricarbonyl chain forms a ring or not. There are a variety of biological activities about flavonoids, such as anti-inflammatory activity, anti-oxidation and anti-tumor activity, and the antiinflammatory activity is apparent. This paper reviews the anti-inflammatory activities and mechanisms of flavonoids and their derivatives reported in China and abroad from 2011 till date (2011-2020), in order to find a good drug scaffold for the study of anti-inflammatory activities.

Preclinical evidence of Yinchenhao decoction on cholestasis: A systematic review and meta-analysis of animal studies

Cholestasis is an important cause of liver fibrosis and cirrhosis. Yinchenhao decoction has been used as a well-known traditional Chinese medicine used in the treatment of cholestasis for over 2,000 years. The purpose of this systematic review is to evaluate the preclinical evidence of Yinchenhao decoction on cholestasis models. The following databases were searched from inception to February 2020. Chinese National Knowledge Infrastructure, VIP medicine information system, Wanfang Database, PubMed, Web of Science, Embase and the Cochrane Library were searched. The content concerned Yinchenhao decoction on different animal model experiments for the treatment of cholestasis. The methodological quality of the included studies was assessed based on the SYstematic Review Center for Laboratory animal Experimentation Animal Experiment Bias Risk Assessment Tool. A meta-analysis was conducted with RevMan 5.3 software according to the Cochrane tool. Nineteen studies on a total of 404 animals were included with five kinds of experimental animal models. The results showed that serum total bilirubin (TBIL), direct bilirubin (DBIL), indirect bilirubin and total bile acid in the group treated with Yinchenhao decoction were significantly lower than those in the model group (P < 0.00001). The alanine aminotransferase (ALT), aspartate aminotransferase and alkaline phosphatase levels in the Yinchenhao decoction group were also significantly reduced (P < 0.00001). The subgroup analysis of the different models showed that Yinchenhao decoction had a significant effect on the bile duct ligation model, and there was a significant reduction in TBIL, DBIL and ALT levels (P < 0.00001) in ANIT-induced cholestasis. After 24 hours of Yinchenhao decoction treatment, there was no significant difference in TBIL levels (P = 0.34), but after 48 and 72 hours of treatment, the TBIL levels were significantly reduced compared with the model group (P < 0.00001). There was no significant difference in DBIL after 48 hours of administration (P = 0.26), but compared with the model group, Yinchenhao decoction could significantly reduce the DBIL levels after 48 hours of treatment (P < 0.0003). Yinchenhao decoction could significantly reduce the ALT levels after 24, 48 and 72 hours (P < 0.006). Yinchenhao decoction was able to significantly reduce the levels of TBIL, DBIL and ALT on different rat species: Wistar and Sprague Dawley (P = 0.0001; P = 0.0002). The preclinical evidence indicated that Yinchenhao decoction might be a potent and promising agent for cholestasis. Moreover, this conclusion should be further confirmed with more well-designed researches.

Metabolic Impact of Flavonoids Consumption in Obesity: From Central to Peripheral

The prevention and treatment of obesity is primary based on the follow-up of a healthy lifestyle, which includes a healthy diet with an important presence of bioactive compounds such as polyphenols. For many years, the health benefits of polyphenols have been attributed to their anti-oxidant capacity as free radical scavengers. More recently it has been described that polyphenols activate other cell-signaling pathways that are not related to ROS production but rather involved in metabolic regulation. In this review, we have summarized the current knowledge in this field by focusing on the metabolic effects of flavonoids. Flavonoids are widely distributed in the plant kingdom where they are used for growing and defensing. They are structurally characterized by two benzene rings and a heterocyclic pyrone ring and based on the oxidation and saturation status of the heterocyclic ring flavonoids are grouped in seven different subclasses. The present work is focused on describing the molecular mechanisms underlying the metabolic impact of flavonoids in obesity and obesity-related diseases. We described the effects of each group of flavonoids in liver, white and brown adipose tissue and central nervous system and the metabolic and signaling pathways involved on them.

The Targeted Impact of Flavones on Obesity-Induced Inflammation and the Potential Synergistic Role in Cancer and the Gut Microbiota

Obesity is an inflammatory disease that is approaching pandemic levels, affecting nearly 30% of the world's total population. Obesity increases the risk of diabetes, cardiovascular disorders, and cancer, consequentially impacting the quality of life and imposing a serious socioeconomic burden. Hence, reducing obesity and related life-threatening conditions has become a paramount health challenge. The chronic systemic inflammation characteristic of obesity promotes adipose tissue remodeling and metabolic changes. Macrophages, the major culprits in obesity-induced inflammation, contribute to sustaining a dysregulated immune function, which creates a vicious adipocyte-macrophage crosstalk, leading to insulin resistance and metabolic disorders. Therefore, targeting regulatory inflammatory pathways has attracted great attention to overcome obesity and its related conditions. However, the lack of clinical efficacy and the undesirable side-effects of available therapeutic options for obesity provide compelling reasons for the need to identify additional approaches for the prevention and treatment of obesity-induced inflammation. Plant-based active metabolites or nutraceuticals and diets with an increased content of these compounds are emerging as subjects of intense scientific investigation, due to their ability to ameliorate inflammatory conditions and offer safe and cost-effective opportunities to improve health. Flavones are a class of flavonoids with anti-obesogenic, anti-inflammatory and anti-carcinogenic properties. Preclinical studies have laid foundations by establishing the potential role of flavones in suppressing adipogenesis, inducing browning, modulating immune responses in the adipose tissues, and hindering obesity-induced inflammation. Nonetheless, the understanding of the molecular mechanisms responsible for the anti-obesogenic activity of flavones remains scarce and requires further investigations. This review recapitulates the molecular aspects of obesity-induced inflammation and the crosstalk between adipocytes and macrophages, while focusing on the current evidence on the health benefits of flavones against obesity and chronic inflammation, which has been positively correlated with an enhanced cancer incidence. We conclude the review by highlighting the areas of research warranting a deeper investigation, with an emphasis on flavones and their potential impact on the crosstalk between adipocytes, the immune system, the gut microbiome, and their role in the regulation of obesity.

Baicalin ameliorates oxidative stress and apoptosis by restoring mitochondrial dynamics in the spleen of chickens via the opposite modulation of NF-κB and Nrf2/HO-1 signaling pathway during Mycoplasma gallisepticum infection

Mycoplasma gallisepticum (MG) infection produces a profound inflammatory response in the respiratory tract and evade birds' immune recognition to establish a chronic infection. Previous reports documented that the flavonoid baicalin possess potent anti-inflammatory, and antioxidant activities. However, whether baicalin prevent immune dysfunction is largely unknown. In the present study, the preventive effects of baicalin were determined on oxidative stress generation and apoptosis in the spleen of chickens infected with MG. Histopathological examination showed abnormal morphological changes including cell hyperplasia, lymphocytes depletion, and the red and white pulp of spleen were not clearly visible in the model group. Oxidative stress-related parameters were significantly (P < 0.05) increased in the model group. However, baicalin treatment significantly (P < 0.05) ameliorated oxidative stress and partially alleviated the abnormal morphological changes in the chicken spleen compared to model group. Terminal deoxynucleotidyl transferase–mediated dUTP nick endlabeling assay results, mRNA, and protein expression levels of mitochondrial apoptosis-related genes showed that baicalin significantly attenuated apoptosis. Moreover, baicalin restored the mRNA expression of mitochondrial dynamics-related genes and maintain the balance between mitochondrial inner and outer membranes. Intriguingly, the protective effects of baicalin were associated with the upregulation of nuclear factor erythroid 2–related factor 2 (Nrf2)/Heme oxygenase-1 (HO-1) pathway and suppression of nuclear factor-kappa B (NF-κB) pathway in the spleen of chicken. In summary, these findings indicated that baicalin promoted mitochondrial dynamics imbalance and effectively prevents oxidative stress and apoptosis in the splenocytes of chickens infected with MG.

Imidacloprid-induced liver fibrosis in quails via activation of the TGF-β1/Smad pathway

Imidacloprid (IMI) is one of the most frequently used neonicotinoid insecticide, and its potential toxicity and environmental hazards have gradually attracted people's attention. Liver fibrosis caused by long-term inflammation or oxidative stress can lead to cirrhosis and liver failure, even death. However, the mechanism of liver fibrosis induced by neonicotinoid insecticide remains unclear. This study investigates whether IMI could induce liver fibrosis in quails and a potential mechanism. Our study used a quail 90-day IMI-induced liver fibrosis model. The results showed that IMI induced histopathological lesions, oxidative stress, inflammation, fibrosis, and changes in nuclear factor-kappa B (NF-κB), nuclear factor-E2-related factor-2 (Nrf2), and transforming growth factor (TGF-β1) levels. Furthermore, IMI enhanced the expression of liver fibrosis marker proteins, including collagen I, α-smooth muscle actin (α-SMA), and fibronectin 1 (FN-1), by activating the TGF-β1/Smad signaling pathway. In conclusion, our study demonstrated that IMI exposure induces liver fibrosis via activation of the TGF-β1/Smad signaling pathway in quails.

Baicalin Protects Against 17α-Ethinylestradiol-Induced Cholestasis via the Sirtuin 1/Hepatic Nuclear Receptor-1α/Farnesoid X Receptor Pathway

Estrogen-induced cholestasis (EIC) is characterized by impairment of bile flow and accumulated bile acids (BAs) in the liver, always along with the liver damage. Baicalin is a major flavonoid component of Scutellaria baicalensis, and has been used in the treatment of liver diseases for many years. However, the role of baicalin in EIC remains to be elucidated. In this study, we demonstrated that baicalin showed obvious hepatoprotective effects in EIC rats by reducing serum biomarkers and increasing the bile flow rate, as well as by alleviating liver histology and restoring the abnormal composition of hepatic BAs. In addition, baicalin protected against estrogen-induced liver injury by up-regulation of the expression of hepatic efflux transporters and down-regulation of hepatic uptake transporters. Furthermore, baicalin increased the expression of hepatic BA synthase (CYP27A1) and metabolic enzymes (Bal, Baat, Sult2a1) in EIC rats. We showed that baicalin significantly inhibited hepatic inflammatory responses in EIC rats through reducing elevated levels of TNF-α, IL-1β, IL-6, and NF-κB. Finally, we confirmed that baicalin maintains hepatic BA homeostasis and alleviates inflammation through sirtuin 1 (Sirt1)/hepatic nuclear receptor-1α (HNF-1α)/farnesoid X receptor (FXR) signaling pathway. Thus, baicalin protects against estrogen-induced cholestatic liver injury, and the underlying mechanism involved is related to activation of the Sirt1/HNF-1α/FXR signaling pathway.

Natural products for the prevention and treatment of cholestasis: A review

Cholestasis is a common manifestation of decreased bile flow in various liver diseases. It results in fibrosis and even cirrhosis without proper treatment. It is believed that a wide range of factors, including transporter dysfunction, oxidative stress, inflammatory damage, and immune disruption, can cause cholestasis. In recent years, natural products have drawn much attention for specific multiple-target activities in diseases. Many attempts have been made to investigate the anticholestatic effects of natural products with advanced technology. This review summarizes recent studies on the biological activities and mechanisms of recognized compounds for cholestasis treatment. Natural products, including various flavonoids, phenols, acids, quinones, saponins, alkaloids, glycosides, and so on, function as comprehensive regulators via ameliorating oxidative stress, inflammation, and apoptosis, restoring bile acid balance with hepatic transporters, and adjusting immune disruption. Moreover, in this progress, nuclear factor erythroid 2-related factor 2, reactive oxygen species production, heme oxygenase-1, NF-κB, cholesterol 7 alpha-hydroxylase, and farnesoid X receptors are thought as main targets for the activity of natural products. Therefore, this review presents the detailed mechanisms that include multiple targets and diverse signalling pathways. Natural products are the valuable when seeking novel therapeutic agents to treat cholestatic liver diseases.

Baicalin and its nanoliposomes ameliorates nonalcoholic fatty liver disease via suppression of TLR4 signaling cascade in mice

As a natural flavonoid compound, baicalin(BA)has been reported to exhibit hepatoprotective and anti-inflammatory properties. However, the characteristic of poor solubility and low bioavailability greatly limits its application. In addition, the effects and underlying mechanisms of BA in nonalcoholic fatty liver disease (NAFLD) remain elusive. In this study, Methionine and choline deficient diet (MCD)-induced NAFLD mice were treated with baicalin or baicalin-loaded nanoliposomes (BA-NL), then hepatic histopathological changes, biochemical parameters and inflammatory molecules were observed. We found that mice in MCD group showed significant increases in plasma transaminase, hepatocyte apoptosis, hepatic lipid accumulation, liver fibrosis, and infiltration of neutrophils and macrophages compared with control group, however, BA and BA-NL markedly attenuated MCD-induced the above changes. Besides, further analysis indicated that BA and BA-NL also inhibited the up-regulation of toll-like receptor 4 (TLR4) signal and the production of inflammatory mediators in MCD mice. Importantly, BA-NL was found to be more effective than baicalin on MCD-induced NAFLD in mice. These data suggested that BA and its nanoliposomes BA-NL could effectively protect mice against MCD-induced NAFLD, which might be mediated through inhibiting TLR4 signaling cascade.

Cholestatic liver disease results increased production of reactive aldehydes and an atypical periportal hepatic antioxidant response

Cholangiopathies such as primary sclerosing cholangitis (PSC) are chronic liver diseases characterized by increased cholestasis, biliary inflammation and oxidative stress. The objective of this study was to elucidate the impact of cholestatic injury on oxidative stress-related factors. Using hepatic tissue and whole cell liver extracts (LE) isolated from 11-week old C57BL/6J (WT) and Mdr2^KO mice, inflammation and oxidative stress was assessed. Concurrently, specific targets of carbonylation were assessed in LE prepared from murine groups as well as from normal and human patients with end-stage PSC. Identified carbonylated proteins were further evaluated using bioinformatics analyses. Picrosirius red staining revealed extensive fibrosis in Mdr2^KO liver, and fibrosis colocalized with increased periportal inflammatory cells and both acrolein and 4-HNE staining. Western blot analysis revealed elevated periportal expression of antioxidant proteins Cbr3, GSTμ, Prdx5, TrxR1 and HO-1 but not GCLC, GSTπ or catalase in the Mdr2^KO group when compared to WT. From immunohistochemical analysis, increased periportal reactive aldehyde production colocalized with elevated staining of Cbr3, GSTμ and TrxR1 but surprisingly not with Nrf2. Mass spectrometric analysis revealed an increase in carbonylated proteins in the Mdr2^KO and PSC groups compared to respective controls. Gene ontology and KEGG pathway analysis of carbonylated proteins revealed a propensity for increased carbonylation of proteins broadly involved in metabolic processes as well more specifically in Rab-mediated signal transduction, lysosomes and the large ribosomal subunit in human PSC. Western blot analysis of Rab-GTPase expression revealed no significant differences in Mdr2^KO mice when compared to WT livers. In contrast, PSC tissue exhibited decreased levels of Rabs 4, 5 and increased abundance of Rabs 6 and 9a protein. Results herein reveal that cholestasis induces stage-dependent increases in periportal oxidative stress responses and protein carbonylation, potentially contributing to pathogenesis in Mdr2^KO. Furthermore, during early stage cholestasis, there is cell-specific upregulation of some but not all, antioxidant proteins.

Baicalin mitigated Mycoplasma gallisepticum-induced structural damage and attenuated oxidative stress and apoptosis in chicken thymus through the Nrf2/HO-1 defence pathway

The thymus is a primary lymphoid organ and plays a critical role in the immune response against infectious agents. Baicalin is a naturally derived flavonoid famous for its pharmacological properties, but the preventive effects of baicalin against immune impairment remain unclear. We examined this effect in the context of Mycoplasma gallisepticum (MG) infection-induced structural damage in the chicken thymus. Histopathological examination showed that the compact arrangement of cells in the thymus was lost in the MG-infected group. Inflammatory cell infiltration and nuclear debris accumulated, and the boundary between the cortex and medulla was not clearly visible. The mRNA and protein expression of apoptosis-related genes were significantly increased in the MG-infected group compared to the control group and the baicalin group. The number of positively stained nuclei in the terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) assay were increased in the MG-infected group. In addition, electron microscopic examination showed chromatin condensation, mitochondrial swelling and apoptotic vesicles in the MG-infected group. However, baicalin treatment significantly alleviated the oxidative stress and apoptosis induced by MG infection. Importantly, the abnormal morphology was partially ameliorated by baicalin treatment. Compared to the MG-infected group, the baicalin-treated group showed significantly reduced expression of apoptosis-related genes at both the mRNA and protein levels. Meanwhile, the nuclear factor erythroid 2-related factor 2 (Nrf2) signalling pathway and downstream genes were significantly upregulated by baicalin to counteract MG-induced oxidative stress and apoptosis in the thymocytes of chickens. In summary, these findings suggest that baicalin treatment efficiently attenuated oxidative stress and apoptosis by activating the Nrf2 signalling pathway and could protect the thymus from MG infection-mediated structural and functional damage.

NRF2 Activation Inhibits Both TGF-β1- and IL-13-Mediated Periostin Expression in Fibroblasts: Benefit of Cinnamaldehyde for Antifibrotic Treatment

Systemic fibrosing or sclerotic disorders are life-threatening, but only very limited treatment modalities are available for them. In recent years, periostin (POSTN), a major extracellular matrix component, was established by several studies as a novel key player in the progression of systemic fibrotic disease. In this research, we revealed the involvement of oxidative stress in the expression of POSTN induced by TGF-β1 and IL-13 in dermal fibroblasts. We found that the antioxidant cinnamaldehyde activated the NRF2/HMOX1 pathway. Cinnamaldehyde also alleviated TGF-β1- and IL-13-mediated production of reactive oxygen species and subsequent POSTN upregulation in dermal fibroblasts. In contrast, NRF2 silencing abolished the cinnamaldehyde-mediated downregulation of POSTN. These results suggest that cinnamaldehyde is a broad inhibitor of POSTN expression covering both TGF-β1 and IL-13 signaling. Cinnamaldehyde may thus be beneficial for the treatment of systemic fibrotic diseases.

Detoxication mechanisms of Radix Tripterygium wilfordii via compatibility with Herba Lysimachia christinae in S180-bearing mice by involving Nrf2

The combined administration between Radix Tripterygium wilfordii Hook F (LGT) and Herba Lysimachia christinae Hance (JQC) belongs to mutual detoxication compatibility of seven emotions in traditional Chinese medicine (TCM) theory. However, until now, the compatibility detoxication mechanisms remain unknown. The present study was undertaken to observe detoxication mechanisms of LGT through compatibility with JQC in tumor-bearing mice by involving NF-E2-related factor 2 (Nrf2)-mediated antioxidant defenses. In addition, influence of compatibility on antitumor activity was also investigated here. Our results demonstrated that compatibility with JQC administration significantly reversed LGT-elevated serum alanine/aspartate transaminase (ALT/AST) levels and alleviated hepatocytes’ swelling or degeneration damage, and at the ratio 2/1 (LGT/JQC) produced the strongest detoxication effect. Besides, compatibility with JQC administration reversed not only LGT-elevated hepatic malondialdehyde (MDA) and tumor necrosis factor-α (TNF-α) but also the LGT lowered GSH, glutathione-s transferase (GST), glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT), and interleukin (IL)-10 levels. Furthermore, compatibility with JQC administration significantly up-regulated protein expression of Nrf2 and mRNA expression of it regulated downstream antioxidant genes such as heme oxygenase-1 (HO-1), NAD(P)H: quinone oxidoreductase-1 (NQO1), and glutamate cysteine ligase catalytic subunit (GCLC). In addition, compatibility with JQC further decreased LGT-decreased tumor weight and at the ratio 2/1 (LGT/JQC) also exerted the strongest synergistic effect. Collectively, through compatibility with JQC exerted detoxication effect on LGT-induced hepatotoxicity and the mechanisms could be at least partly attributed to up-regulation of Nrf2 and its downstream signals, thereby enhancing antioxidant defenses, and inhibiting lipid peroxidation, oxidative stress, and inflammation. Additionally, at the ratio 2/1 (LGT/JQC) exerted the strongest effects on both detoxication and synergism.

Metabolomic Assessment of Acute Cholestatic Injuries Induced by Thioacetamide and by Bile Duct Ligation, and the Protective Effects of Huang-Lian-Jie-Du-Decoction

Huang-Lian-Jie-Du-Decoction, a traditional Chinese formula, has been reported to protect liver from various injuries. Two cholestasis models of rats induced by thioacetamide and by bile duct ligation were established and treated with Huang-Lian-Jie-Du-Decoction. Nuclear Magnetic Resonance-based urinary metabolic profiles were analyzed by orthogonal partial least squares discriminant analysis and univariate analysis to excavate differential metabolites associated with the injuries of the two models and the treatment effects of Huang-Lian-Jie-Du-Decoction. The two cholestatic models shared common metabolic features of excessive fatty acid oxidation, insufficient glutathione regeneration and disturbed gut flora, with specific characteristics of inhibited urea cycle and DNA damage in thioacetamide-intoxicated model, and perturbed Kreb's cycle and inhibited branched chain amino acid oxidation in bile duct ligation model. With good treatment effects, Huang-Lian-Jie-Du-Decoction could regain the balance of the disturbed metabolic status common in the two cholestasis injuries, e.g., unbalanced redox system and disturbed gut flora; and perturbed urea cycle in thioacetamide-intoxicated model and energy crisis (disturbed Kreb's cycle and oxidation of branched chain amino acid) in bile duct ligation model, respectively.

Baicalin modulates the Treg/Teff balance to alleviate uveitis by activating the aryl hydrocarbon receptor

Autoimmune uveitis is a sight-threatening ocular inflammatory disorder. Immunological inflammation is regarded as the key to pathogenesis in autoimmune uveitis. Baicalin, the major bioactive component of Scutellaria baicalensis, possesses immunomodulatory properties. However, the role of baicalin in uveitis and its underlying mechanisms remain unclear. In the current study, we found that baicalin treatment obviously inhibited the intraocular inflammatory process in mice with experimental autoimmune uveitis, along with clear declines in infiltrated inflammatory cells and inflammatory cytokine transcription in the retina and draining lymph nodes. Furthermore, baicalin treatment increased the frequency and number of regulatory T cells and decreased the frequency and number of effector T cells (Th1 and Th17 cells) in the draining lymph nodes of mice with experimental autoimmune uveitis. In vitro, baicalin treatment suppressed interphotoreceptor retinoid binding protein-specific CD4+ T cell proliferation and converted CD4+ T cell differentiation. Furthermore, the expression of aryl hydrocarbon receptor was activated by baicalin treatment. Baicalin-mediated modulation of CD4+ T cell differentiation was partially abrogated by the suppression of aryl hydrocarbon receptor. These findings suggest that baicalin modulates the Treg/Teff balance and CD4+ T cell proliferation to ameliorate experimental autoimmune uveitis by activating the aryl hydrocarbon receptor.

Honokiol Ameliorates Myocardial Ischemia/Reperfusion Injury in Type 1 Diabetic Rats by Reducing Oxidative Stress and Apoptosis through Activating the SIRT1-Nrf2 Signaling Pathway

Reducing oxidative stress is a crucial therapeutic strategy for ameliorating diabetic myocardial ischemia/reperfusion (MI/R) injury. Honokiol (HKL) acts as an effective cardioprotective agent for its strong antioxidative activity. However, its roles and underlying mechanisms against MI/R injury in type 1 diabetes (T1D) remain unknown. Since SIRT1 and Nrf2 are pivotal regulators in diabetes mellitus patients suffering from MI/R injury, we hypothesized that HKL ameliorates diabetic MI/R injury via the SIRT1-Nrf2 signaling pathway. Streptozotocin-induced T1D rats and high-glucose-treated H9c2 cells were exposed to HKL, with or without administration of the SIRT1 inhibitor EX527, SIRT1 siRNA, or Nrf2 siRNA, and then subjected to I/R operation. We found that HKL markedly improved the postischemic cardiac function, decreased the infarct size, reduced the myocardial apoptosis, and diminished the reactive oxygen species generation. Intriguingly, HKL remarkably activated SIRT1 signaling, enhanced Nrf2 nuclear translocation, increased antioxidative signaling, and decreased apoptotic signaling. However, these effects were largely abolished by EX527 or SIRT1 siRNA. Additionally, our cellular experiments showed that Nrf2 siRNA blunted the cytoprotective effects of HKL, without affecting SIRT1 expression and activity. Collectively, these novel findings indicate that HKL abates MI/R injury in T1D by ameliorating myocardial oxidative damage and apoptosis via the SIRT1-Nrf2 signaling pathway.

Huangqi Decoction Alleviates Alpha-Naphthylisothiocyanate Induced Intrahepatic Cholestasis by Reversing Disordered Bile Acid and Glutathione Homeostasis in Mice

Intrahepatic cholestasis is a serious symptom of liver disorders with limited therapies. In this study, we investigated the efficacy of Huangqi decoction (HQD), a two-herb classic traditional Chinese medicine (TCM), in the treatment of alpha-naphthylisothiocyanate (ANIT)-induced intrahepatic cholestasis in mice. HQD treatment ameliorated impaired hepatic function and tissue damage. A metabolomics study revealed that the endogenous metabolites significantly affected by HQD were related to bile acid (BA) biosynthesis and glutathione metabolism pathways. HQD treatment decreased the intrahepatic accumulation of cytotoxic BAs, normalized serum BA levels, and increased biliary and urinary BA excretion. Additionally, HQD restored the hepatic glutathione content and suppressed reactive oxygen species (ROS) in cholestatic mice. Protein and gene analysis revealed that HQD increased the expression of the hepatic metabolizing enzymes cytochrome P450 (CYP) 2B10 and UDP glucuronosyltransferase family 1 member A1 (UGT1A1), as well as multidrug resistance-associated protein 2 (Mrp2), Mrp3, and Mrp4, which play crucial roles in BA homeostasis. Further, HQD increased the protein expression of glutamate-cysteine ligase, which is involved in the synthesis of glutathione. Importantly, HQD increased the nuclear expression of nuclear factor-E2-related factor-2 (Nrf2). In conclusion, HQD protects against intrahepatic cholestasis by reversing the disordered homeostasis of BAs and glutathione.

Baicalin attenuates non-alcoholic steatohepatitis by suppressing key regulators of lipid metabolism, inflammation and fibrosis in mice

AIMS

Baicalin (BA), an active flavonoid compound originating from the herb of Scutellaria baicalensis Georgi, has been previously shown to exert anti-inflammation and anti-oxidant effects in liver diseases. However, the potential role of BA in the regulation of non-alcoholic steatohepatitis (NASH) remains elusive. In this study, we newly explored the hepatoprotective effects of BA in MCD diet-induced NASH by ameliorating hepatic steatosis, inflammation, fibrosis and apoptosis.

MAIN METHODS

NASH was induced in mice fed a methionine and choline-deficient (MCD) diet for 4weeks. The mice were simultaneously treated with or without BA for 4weeks. Serum liver functional markers and inflammatory indicators were assessed by biochemical and ELISA methods, respectively. The livers were histologically examined using H&E, Oil Red O and Masson's trichrome staining methods. The qRT-PCR, IHC and Western blotting assays were applied to analyze mechanisms underlying BA protection.

KEY FINDINGS

BA treatment significantly attenuated MCD diet-induced hepatic lipid accumulation partly through regulating the expression of SREBP-1c, FASN, PPARα and CPT1a. BA treatment dramatically suppressed MCD diet-induced hepatic inflammation, which was associated with decrease in serum TNF-α, IL-1β and MCP-1 production, macrophage influx and suppression of nuclear factor-κB activation. Additionally, BA was proved to prevent liver fibrosis, which appears to be mediated by inhibition of α-SMA, TGF-β1 and Col1A1. Furthermore, BA markedly inhibited hepatocyte apoptosis and cleaved caspase-3 protein expression in MCD diet-induced mice.

SIGNIFICANCE

These results provide a possible basis of the underlying mechanism for the application of BA in the treatment of NASH.