Protective Effect of Oligonol on Dimethylnitrosamine-Induced Liver Fibrosis in Rats via the JNK/NF-κB and PI3K/Akt/Nrf2 Signaling Pathways

Treatment with autophagic inhibitors enhances oligonol‑induced apoptotic effects in nasopharyngeal carcinoma cells

Although the combination of chemotherapy and radiotherapy has increased the survival rate of patients with nasopharyngeal carcinoma (NPC), certain patients do not respond well to the treatment and have a poor prognosis. Therefore, novel therapeutic drugs and strategies to improve prognosis of patients with NPC are required. As certain plant extracts can suppress the viability of cancer cells, the present study investigated whether oligonol, a polyphenolic compound primarily found in lychee fruit, exerts anticancer activities in NPC cells. MTT, ELISA and immunoblotting were performed to investigate cell survival, cytokeratin-18 fragment release, and the expression of apoptosis and autophagy markers, respectively. Oligonol decreased the viability of NPC-TW01 and NPC/HK1NPC cell lines. Oligonol increased the protein expression of several apoptosis markers, including cleaved caspase-8 and -3, cleaved PARP and cytokeratin 18 fragment. Moreover, it also increased expression of autophagy markers Beclin 1 and LC3-II, as well as LC3-II/LC3-I ratio in both NPC cell lines. Furthermore, treatment with autophagy inhibitors 3-methyladenine or LY294002 significantly increased oligonol-induced viability inhibition in NPC-TW01 cells. Combined treatment of oligonol + LY294002 reduced LC3-II expression and the LC3II/LC3I ratio while increasing cleaved caspase-8 and -3, cleaved PARP and cytokeratin 18 fragment expression in NPC-TW01 cells. These findings indicated autophagy inhibitors could enhance viability inhibition and apoptotic effects induced by oligonol in NPC cells.

Liquid Chromatography/Tandem Mass Spectrometry Analysis of Sophora flavescens Aiton and Protective Effects against Alcohol-Induced Liver Injury and Oxidative Stress in Mice

In this study, we investigated the hepatoprotective effects of an ethanol extract of Sophora flavescens Aiton (ESF) on an alcohol-induced liver disease mouse model. Alcoholic liver disease (ALD) was caused by the administration of ethanol to male C57/BL6 mice who were given a Lieber-DeCarli liquid diet, including ethanol. The alcoholic fatty liver disease mice were orally administered ESF (100 and 200 mg/kg bw/day) or silymarin (50 mg/kg bw/day), which served as a positive control every day for 16 days. The findings suggest that ESF enhances hepatoprotective benefits by significantly decreasing serum levels of aspartate transaminase (AST) and alanine transaminase (ALT), markers for liver injury. Furthermore, ESF alleviated the accumulation of triglyceride (TG) and total cholesterol (TC), increased serum levels of superoxide dismutase (SOD) and glutathione (GSH), and improved serum alcohol dehydrogenase (ADH) activity in the alcoholic fatty liver disease mice model. Cells and organisms rely on the Kelch-like ECH-associated protein 1- Nuclear factor erythroid 2-related factor 2 (Keap1-Nrf2) system as a critical defensive mechanism in response to oxidative stress. Therefore, Nrf2 plays an important role in ALD antioxidant responses, and its level is decreased by increased reactive oxidation stress (ROS) in the liver. ESF increased Nrf2, which was decreased in ethanol-damaged livers. Additionally, four polyphenol compounds were identified through a qualitative analysis of the ESF using LC-MS/MS. This study confirmed ESF's antioxidative and hangover-elimination effects and suggested the possibility of using Sophora flavescens Aiton (SF) to treat ALD.

Integrative Transcriptomic Analysis Reveals Upregulated Apoptotic Signaling in Wound-Healing Pathway in Rat Liver Fibrosis Models

Liver fibrosis, defined by the aberrant accumulation of extracellular matrix proteins in liver tissue due to chronic inflammation, represents a pressing global health issue. In this study, we investigated the transcriptomic signatures of three independent liver fibrosis models induced by bile duct ligation, carbon tetrachloride, and dimethylnitrosamine (DMN) to unravel the pathological mechanisms underlying hepatic fibrosis. We observed significant changes in gene expression linked to key characteristics of liver fibrosis, with a distinctive correlation to the burn-wound-healing pathway. Building on these transcriptomic insights, we further probed the p53 signaling pathways within the DMN-induced rat liver fibrosis model, utilizing western blot analysis. We observed a pronounced elevation in p53 protein levels and heightened ratios of BAX/BCL2, cleaved/pro-CASPASE-3, and cleaved/full length-PARP in the livers of DMN-exposed rats. Furthermore, we discovered that orally administering oligonol-a polyphenol, derived from lychee, with anti-oxidative properties-effectively countered the overexpressions of pivotal apoptotic genes within these fibrotic models. In conclusion, our findings offer an in-depth understanding of the molecular alterations contributing to liver fibrosis, spotlighting the essential role of the apoptosis pathway tied to the burn-wound-healing process. Most importantly, our research proposes that regulating this pathway, specifically the balance of apoptosis, could serve as a potential therapeutic approach for treating liver fibrosis.

An update on animal models of liver fibrosis

The development of liver fibrosis primarily determines quality of life as well as prognosis. Animal models are often used to model and understand the underlying mechanisms of human disease. Although organoids can be used to simulate organ development and disease, the technology still faces significant challenges. Therefore animal models are still irreplaceable at this stage. Currently, in vivo models of liver fibrosis can be classified into five categories based on etiology: chemical, dietary, surgical, transgenic, and immune. There is a wide variety of animal models of liver fibrosis with varying efficacy, which have different implications for proper understanding of the disease and effective screening of therapeutic agents. There is no high-quality literature recommending the most appropriate animal models. In this paper, we will describe the progress of commonly used animal models of liver fibrosis in terms of their development mechanisms, applications, advantages and disadvantages, and recommend appropriate animal models for different research purposes.

Syringic and ascorbic acids prevent NDMA-induced pulmonary fibrogenesis, inflammation, apoptosis, and oxidative stress through the regulation of PI3K-Akt/PKB-mTOR-PTEN signaling pathway

Idiopathic lung fibrosis (ILF) is a severe and life threatening lung disorder that is characterized by scarring of lung tissue, leading to thickening and stiffening of affected areas. This study looked at the role played by PI3K-Akt/PKB-mToR signaling pathway in the pathogenesis of N-Nitrosodimethylamine (NDMA)-induced lung fibrotic injury, and the effects of syringic acid (SYR) and ascorbic acid (ASC) treatments in male Wistar rats. Pulmonary fibrosis was induced by intraperitoneal injection of 10 mg/kg NDMA once daily, thrice (consecutively) a week for four weeks, and this condition was treated daily with SYR (50 mg/kg) and ASC (100 mg/kg) acids orally for four weeks. Fibrogenesis, following NDMA administration was marked by a significant increase in collagen-1 and α-SMA levels, while oxidative stress was marked by a significant decrease in GSH level, GST, GPx, CAT, and SOD activities. Also, NDMA significantly increased lung Bax, p53, caspase-3, TNF-α, IL-1β, NFkB, and decreased Bcl-2, mdm2, cyclin D1 and Nrf-2 levels. Looking at the PI3K-Akt-mTOR signaling pathway, NDMA administration significantly activated lung PI3K, Akt, and mTOR, and deactivated PTEN, FoxO1 and TSC2. Treatments with SYR and ASC significantly reduced oxidative stress by restoring the antioxidant systems via Nrf2 activation, decreased the levels of inflammatory markers through inhibition of NFkB, downregulated p53, Bax, and caspase-3 via up-regulation of mdm2 and cyclin D1. SYR and ASC also regulated the PI3K-Akt-mTOR signaling pathway via the deactivation of PI3K, Akt, and mTOR, and up-regulation of PTEN, FoxO1 and TSC2. Overall, SYR and ASC modulate the PI3K-Akt-mTOR signaling pathway via inhibition of oxidative stress, inflammation and apoptosis in NDMA-induced lung fibrosis.

Effect of oligonol, a lychee-derived polyphenol, on skeletal muscle in ovariectomized rats by regulating body composition, protein turnover, and mitochondrial quality signaling

Oligonol is a low‐molecular‐weight polyphenol product derived from lychee (Litchi chinensis Sonn.) fruits. This study was focused on the effects of oligonol on the skeletal muscle of ovariectomized rats. We randomly divided female Sprague–Dawley rats into three groups: a sham surgery control group (Sham), an ovariectomy (OVX) group, and an OVX group treated with oligonol (OVX + Oligonol). Oligonol was intraperitoneally administrated at 30 mg/kg daily for 6 weeks. Oligonol treatment after OVX decreased body weight and fat mass, regulated lipid metabolism in skeletal muscle, without loss of lean mass and bone. Bone turnover was not affected by oligonol. In protein synthesis and degradation, oligonol increased the levels of the mammalian target of rapamycin and its downstream targets, eukaryotic initiation factor 4E‐binding protein 1 and 70‐kDa ribosomal protein S6 kinase, and it stimulated the expression of ubiquitin‐proteasome pathway proteins, the forkhead box transcription factors of the class O and the muscle ring‐finger protein‐1. Moreover, oligonol treatment enhanced mitochondrial biogenesis and dynamics. Thus, our results indicated that oligonol treatment had beneficial effects on the skeletal muscle in an estrogen‐deficiency rat model.

Design and optimization of cranberry extract loaded bile salt augmented liposomes for targeting of MCP-1/STAT3/VEGF signaling pathway in DMN-intoxicated liver in rats

Cranberry extract (CBE) is a major source of the antioxidant polyphenolics but suffers from limited bioavailability. The goal of this research was to encapsulate the nutraceutical (CBE), into bile salt augmented liposomes (BSALs) as a promising oral delivery system to potentiate its hepatoprotective impact against dimethylnitrosamine (DMN) induced liver injury in rats. The inclusion of bile salt in the liposomal structure can enhance their stability within the gastrointestinal tract and promote CBE permeability. CBE loaded BSALs formulations were fabricated utilizing a (2³) factorial design to explore the impact of phospholipid type (X₁), phospholipid amount (X₂), and sodium glycocholate (SGC) amount (X₃) on BSALs properties, namely; entrapment efficiency percent, (EE%); vesicle size, (VS); polydispersity index; (PDI); zeta potential, (ZP); and release efficiency percent, (RE%). The optimum formulation (F1) exhibited spherical vesicles with EE% of 71.27 ± 0.32%, VS; 148.60 ± 6.46 nm, PDI; 0.38 ± 0.02, ZP; −18.27 ± 0.67 mV and RE%; 61.96 ± 1.07%. Compared to CBE solution, F1 had attenuated DMN-induced hepatic injury, as evidenced by the significant decrease in serum level of ALT, AST, ALP, MDA, and elevation of GSH level, as well as SOD and GPX activities. Furthermore, F1 exhibited an anti-inflammatory character by suppressing TNF-α, MCP-1, and IL-6, as well as downregulation of VEGF-C, STAT-3, and IFN-γ mRNA levels. This study verified that when CBE was integrated into BSALs, F1, its hepatoprotective effect was significantly potentiated to protect the liver against DMN-induced damage. Therefore, F1 could be deliberated as an antioxidant, antiproliferative, and antifibrotic therapy to slow down the progression of hepatic damage.

Piperine inhibits AML-12 hepatocyte EMT and LX-2 HSC activation and alleviates mouse liver fibrosis provoked by CCl4: roles in the activation of the Nrf2 cascade and subsequent suppression of the TGF-β1/Smad axis

Piperine (PIP) is an alkaloid derived from peppercorns. Herein, we assessed its effects on hepatocyte EMT and HSC activation in vitro and CCl₄-elicited liver fibrosis in mice. Further experiments were performed to unveil the molecular mechanisms underlying the hepatoprotective activity of PIP. We found that PIP inhibited TGF-β1-provoked AML-12 hepatocyte EMT and LX-2 HSC activation. Mechanistically, in AML-12 and LX-2 cells, PIP evoked Nrf2 nuclear translocation and increased transcriptions of Nrf2-responsive antioxidative genes. These events decreased TGF-β1-induced production of ROS. Moreover, PIP increased the expression of Smad7, suppressed phosphorylation and nuclear translocation of Smad2/3, and decreased the transcriptions of Smad2/3-downstream genes. Knockdown of Nrf2 abrogated the protective activity of PIP against TGF-β1. Modulatory effects of PIP on the TGF-β1/Smad cascade were also crippled, which suggested that activation of Nrf2 played critical roles in the regulatory effects of PIP on TGF-β1/Smad signaling. Experiments in vivo unveiled that PIP ameliorated mouse liver fibrosis provoked by CCl₄. PIP modulated the intrahepatic contents of the markers of EMT and HSC activation. In mouse livers, PIP activated Nrf2 signaling and reduced Smad2/3-dependent gene transcriptions. Our findings collectively suggested PIP as a new chemical entity with the capacity of alleviating liver fibrosis. The activation of the Nrf2 cascade and subsequent suppression of the TGF-β1/Smad axis are implicated in the hepatoprotective activity of PIP.