Amelioration effect of black seed oil against high-fat diet-induced obesity in rats through Nrf2/HO-1 pathway

Obesity is a chronic inflammatory disease that represents a risk factor for number of diseases including diabetes, steatohepatitis, and cancer. Using safe natural compounds to ameliorate obesity and its related metabolic syndrome is an interesting spot for research. We investigated the regulatory role and the underlying mechanism of black seed oil (BSO) on high-fat diet (HFD)-induced obesity in rats. The study included two models: the first one aimed to study the prophylactic effect of BSO (BSO administration for 10 weeks along with HFD) while the second one aimed to study the treatment role of BSO (BSO administration starting from the 10th week for 4 weeks along with HFD). BSO significantly decreased insulin resistance and body weight characteristics in both models. It also normalized lipid profile. Moreover, histopathological examination confirmed these results as BSO significantly decreased adipocyte size and hepatic lipid deposition. Besides, BSO alleviated HFD-induced oxidative stress as indicated by significant increase in the total antioxidant capacity and significant decrease in liver malondialdehyde. Moreover, BSO decreased significantly liver gluconeogenic enzymes mRNA expressions (phosphoenolpyruvate carboxykinase and glucose-6-phosphatase) and increased significantly heme oxygenase-1 (HO-1), nuclear factor erythroid-2-related factor-2 (Nrf2) and insulin receptor mRNA expressions. In conclusion, BSO represents a natural therapy that has the ability to prevent and treat HFD-induced obesity in rats that may be mediated through Nrf2/HO-1 pathway's activation and insulin receptor expression's increase. To our best knowledge, this study represents a novel study that investigates the regulatory role of BSO on Nrf2 pathway in preventing and treating HFD-induced obesity. PRACTICAL APPLICATIONS: Black seed oil is a natural available safe supplement, thus it can be used for prevention from obesity and even treatment of obesity and obesity related complications. Introducing of black seed oil in the treatment regimen of obese patients may be promising.

Sesamol Upregulates Death Receptors and Acts as a Chemosensitizer in Solid Ehrlich Carcinoma Model in Mice

AIMS

The aim of the present study was to investigate the anti-tumor effect of sesamol (SML), a nutritional phenolic compound of sesame, in solid Ehrlich carcinoma (SEC) model in mice and its ability to enhance doxorubicin (DOX) anti-tumor activity. Moreover, we analyzed the ability of SML to protect against DOX-induced cardiotoxicity.

MAIN METHODS

SML (70 mg/kg), DOX (2 mg/kg) and their combination were given to mice bearing SEC for 21 day. The mRNA level of Fas, FasL, TRAILR2, TRAIL, caspase-3 and Bcl-2 were assessed by qPCR. Tumor and cardiac tissues were examined for histopathological changes by hematoxylin and eosin. Active caspase-3 was scored by immunohistochemical analysis.

KEY FINDINGS

SML treatment significantly decreased solid tumor size and weight. In addition, SML enhanced DOX anti-tumor activity. SML treatment either alone or in combination with DOX induced upregulation of Fas/FasL and TRAILR2/TRAIL gene expression. Moreover, SML increased caspase-3 protein and gene expressions and decreased Bcl-2 gene expression.

SIGNIFICANCE

SML upregulates death receptors expression and enhances apoptosis induction in tumor cells that may explain its anti-tumor activity. Not only that, but SML also enhances DOX anti-tumor activity and attenuates its cardiotoxicity.

Vitamin D potentiates anti-tumor activity of 5-fluorouracil via modulating caspase-3 and TGF-β1 expression in hepatocellular carcinoma-induced in rats

We investigated the role of vitamin D (Vit D) alone and in combination with 5-fluorouracil (5-FU) in thioacetamide (TAA)-induced hepatocellular carcinoma (HCC) in rats. Fifty male Sprague-Dawley rats were randomized into a control group and 4 groups that received TAA (200 mg/kg, i.p.) twice per week for 16 weeks. These 4 groups were further divided as follows: HCC group; 5-FU group (75 mg/kg, i.p., once weekly for 3 weeks starting from the 12th week); Vit D group (200 IU/kg daily by oral tube for 16 weeks); and 5-FU + Vit D group (received the previously mentioned dosage regimens of 5-FU and Vit D). HCC was detected by histopathological changes in liver sections and the elevation of serum α-fetoprotein (AFP). Treatment with 5-FU + Vit D significantly decreased gene expression of nuclear factor erythroid 2-related factor 2 (NrF2) and transforming growth factor β1 (TGF-β1) at both the gene and protein level and serum AFP concentrations in comparison with their corresponding monotherapy. Moreover, 5-FU + Vit D treatment enhanced apoptosis by increasing caspase-3 gene and protein expression. Conclusively, Vit D enhances antitumor activity of 5-FU in an HCC-induced model and improves liver function of treated animals. Combination therapy in a TAA-induced HCC rat model was more effective than 5-FU or Vit D through the modulation of TGF-β1, caspase-3, and NrF2 expressions.

Antioxidant and anti-inflammatory activities of berberine attenuate hepatic fibrosis induced by thioacetamide injection in rats

Berberine (BBR) is an isoquinoline alkaloid extracted from the roots, rhizomes and stems of coptis. Liver fibrosis is a worldwide health problem with no established therapy until now. The aim of our study is to investigate the efficacy of BBR on hepatic fibrosis induced in rats and to uncover other mechanisms. Rats were injected with thioacetamide (TAA) (200 mg/kg, i.p) twice per week for 6 weeks to induce fibrosis. Treated groups were gavaged with BBR (50 mg/kg/day, p.o) simultaneously with TAA injection. Hepatic antioxidant enzymes (catalase, SOD, GPx) were assessed in hepatic homogenate. Their activities were attenuated by TAA injection and elevated by BBR administration. Additionally, serum IL-6 and mRNA levels of IL-1β, IL-6, IL-10 and IFN-γ were evaluated as inflammatory markers. Our results showed that BBR suppressed the inflammation induced by TAA injection. Tissue expression of α-SMA (marker of activated HSCs), TGF-β1 and fibronectin were measured by immunohistochemistry as well as mRNA expressions of TGF-β1 and fibronectin were quantified as fibrotic markers. The collagen deposition in hepatic tissues was assessed by Masson's trichome staining. BBR significantly alleviated TGF-β1 production, decreased collagen and fibronectin deposition and consequently attenuated hepatic fibrogenesis. Akt pathway controls cell survival, proliferation, migration and adhesion. The relative phosphorylation of Akt was determined in hepatic homogenates that was increased with TAA injection and decreased by BBR treatment. Inhibition of Akt pathway has been linked to the intrinsic pathway of apoptosis. Caspase-3, caspase-9, Bcl-2 and Bax were quantified as apoptotic markers using qPCR and also caspase-3 by immunohistochemistry. BBR-treated rats showed an increase in the expression of apoptotic markers. Moreover, BBR-treated rats showed restoration of normal liver lobular architecture as shown by H&E staining. In conclusion, BBR is a potential therapeutic candidate for liver fibrosis owing to its antioxidant and anti-inflammatory activities.

Hepatoprotective Effect of Curcumin on Hepatocellular Carcinoma Through Autophagic and Apoptic Pathways

BACKGROUND AND RATIONALE

Microtubule-associated protein light chain 3-II (LC3-II), and Sequestosome-1 (SQSTM1) are proteins that can be used as markers for autophagic pathway. Bcl-2 protein is reported to be inversely correlated with apoptosis. We aimed to investigate the effects of curcumin on liver inflammation and fibrosis up to the first dysplastic stage of Hepatocellular carcinoma (HCC) induced by Thioacetamide (TAA) in rats and to clarify the effects of curcumin on LC3-II, SQSTM1, and Bcl-2. Male Sprague-Dawley rats were randomized into four groups: Control group, TAA group, Curcumin low-dose group, and Curcumin highdose group. The last three groups received TAA 200 mg/kg i.p. twice weekly for 18 weeks. Oxidative stress markers as hepatic malondialdehyde (MDA) concentration and superoxide dismutase (SOD) activity were measured by colorimetric methods. Hepatic SQSTM1 concentration was measured by ELISA, and gene expression levels of Bcl-2, and LC3-II were measured by RT-PCR.We also investigated the in vitro effect of curcumin on HepG2 cells viability through MTT assay, and the involvement of autophagy in this effect.

RESULTS

Curcumin increased the survival percent in rats, decreased -fetoprotein (AFP) concentration, and serum aspartate aminotransferase (AST) activity, and increased serum albumin concentration. Curcumin also significantly reduced oxidative stress in liver, inhibited apoptosis, and induced autophagy. In vitro, curcumin (50 µM) decreased HepG2 cells viabilityand the concentration of SQSTM1.

CONCLUSIONS

Curcumin leads to protection against TAA induced HCC up to the first dysplastic stage through activating autophagic pathway and inhibiting apoptosis. Also, the antioxidant activity of curcumin almost prevents liver fibrosis.

Silymarin and caffeine combination ameliorates experimentally-induced hepatic fibrosis through down-regulation of LPAR1 expression

AIMS

Lysophosphatidic acid is a lipid mediator that is supposed to be implicated in hepatic fibrosis. Silymarin and caffeine are natural compounds known for their anti-inflammatory and antioxidant effects. Our study aimed to explore the effect of silymarin, caffeine, and their combination on lysophosphatidic acid receptor 1 (LPAR1) pathway in thioacetamide (TAA)-induced hepatic fibrosis.

MAIN METHODS

Hepatic fibrosis was induced in male Sprague-Dawley rats by intraperitoneal injection of 200 mg/kg of TAA twice a week for 8 weeks. Silymarin (50 mg/kg), caffeine (50 mg/kg), and their combination (50 mg/kg silymarin + 50 mg/kg caffeine) were orally given to rats every day for 8 weeks along with TAA injection. Liver functions were measured. Histopathological examination of liver tissues was performed using hematoxylin and eosin and Masson's trichrome staining. mRNA expressions of LPAR1, transforming growth factor beta 1 (TGF-β1), connective tissue growth factor (CTGF), and alpha smooth muscle actin (α-SMA) were measured using RT-PCR. LPAR1 tissue expression was scored using immunohistochemistry.

KEY FINDINGS

Silymarin, caffeine, and their combination significantly improved liver function. They caused significant decrease in fibrosis and necro-inflammatory scores. Combination of silymain and caffeine caused a significant decrease in the necro-inflammatory score than the single treatment with silymarin or caffeine. In addition, silymarin, caffeine, and their combination significantly decreased hepatic LPAR1, TGF-β1, CTGF, and α-SMA gene expressions and LPAR1 tissue expression.

SIGNIFICANCE

Silymarin, caffeine, and their combination protect against liver fibrosis through down-regulation of LPAR1, TGF-β1, and CTGF.

Glycyrrhizin ameliorates high fat diet-induced obesity in rats by activating NrF2 pathway

AIM

Obesity based on insulin resistance is a state of chronic oxidative stress and inflammation that are highly regulated through nuclear factor Erythroid 2-related factor 2 (NrF2) pathway.

MATERIALS AND METHODS

70 male Wistar rats were randomized into two models. The prophylactic model was 10weeks and rats were grouped into: normal group, GL group (received glycyrrhizin 50mg/kg/day orally along with normal pellet diet), HFD group and HFD+ GL group (received glycyrrhizin along with HFD). The treatment model was 14weeks and rats were grouped into: normal group, HFD group and HFD+GL group (received glycyrrhizin from the week 10).

KEY FINDINGS

Glycyrrhizin decreased significantly rat weights and insulin resistance, normalized lipid profile and reduced significantly the adipocytes size in adipose tissue and lipid deposition in the liver tissue through histopathologic examination. Furthermore, glycyrrhizin ameliorated obesity-induced oxidative stress which indicated by significant decrease in liver malondialdehyde level (P<0.001) and increase in the total antioxidant capacity (P<0.001). Interestingly, molecular mechanism of glycyrrhizin was explored, that included significant reduction of liver gluconeogenic enzymes mRNA expression (P<0.001), a significant increase of liver insulin receptor, NrF2 and homooxygenase-1 mRNA expressions (P<0.001) and significant increase and nuclear translocation of NrF2 in liver tissue.

SIGNIFICANCE

Glycyrrhizin ameliorates HFD-induced obesity in rats that may be attributed to its ability to increase insulin receptor expression and to activate NrF2 and subsequent homooxygenase-1 pathway. Thus, this work represents a safe natural compound (glycyrrhizin) that has a great role either as prophylaxis or treatment for insulin resistance related to obesity.

Chloroquine upregulates TRAIL/TRAILR2 expression and potentiates doxorubicin anti-tumor activity in thioacetamide-induced hepatocellular carcinoma model

Impaired apoptosis and systemic toxicity of chemotherapeutic drugs make cancer treatment suboptimal. Thus, there is urgency for drug repurposing which facilitates discovery of safe and effective combination therapy. This study aimed to evaluate chloroquine's (CQ) ability to trigger TRAIL/TRAILR2 apoptotic pathway in thioacetamide (TAA)-induced hepatocellular carcinoma (HCC) either alone or in combination with doxorubicin (DOX). Moreover, its ability to attenuate DOX-induced cardiotoxicity was investigated. TAA was injected in male Sprague Dawely rats (200 mg/kg; ip; 2 times/week) for 16 weeks. After the 16th week, rats were further divided into different groups (n = 10) and treated for 7 weeks. CQ group (received CQ 25 mg/kg/day; orally), DOX group (received DOX 1 mg/kg; ip; 2 times/week) and CQ/DOX group. Liver function biomarkers, AFP, hepatic levels of MDA and GSH, serum CK-MB and LDH enzymes activity were measured. Quantitative, Real-Time PCR was used to measure TRAIL, TRAILR2, caspase-8, caspase-9, caspase-3, BCL-2 and TGF-β1 genes expression levels. Necroinflammation and fibrosis were scored by histopathological examination. CQ improved liver functions, reduced AFP level and attenuated HCC progression. CQ induced apoptosis via upregulation of TRAIL/TRAILR2, caspase-8, caspase-3 and caspase-8 genes and downregulation of BCL-2 gene. Moreover, CQ/DOX showed marked decrease in hepatic MDA level, serum CK-MB, LDH enzymes activity, as well as marked increase in hepatic GSH level. In conclusion, this work assess the in vivo efficacy of CQ/DOX combination therapy in this HCC model that not only has enhanced anti-tumor activity but it also protects against DOX-induced cardiotoxicity. Nevertheless, more studies should be performed to illustrate the molecular mechanism of CQ's cardioprotective effect.

Expression of large tenascin-C splice variants by hepatic stellate cells/myofibroblasts in chronic hepatitis C

BACKGROUND/AIMS

Earlier studies have suggested involvement of tenascin-C (TN-C) in liver fibrosis. Here, we examined expression of TN-C variants and types of alternatively spliced fibronectin-type III (FNIII) repeats in chronic hepatitis.

METHODS

Using three monoclonal antibodies against TN-C variants, immunohistochemical staining was performed and the correlation with histological parameters of chronic hepatitis C was examined. The cellular source was also determined and variant expression and their types were tested using isolated rat hepatic stellate cells (HSCs), liver myofibroblasts, and/or LI90 cells.

RESULTS

Large variants were not expressed in normal liver, but were up-regulated in chronic hepatitis, especially at sites of interface hepatitis and confluent necrosis, showing stronger correlations between staining intensity and these than with other parameters or fibrosis. TN-C deposition was closely correlated with increase in the number of alpha-smooth muscle actin-positive cells, i.e. activated HSCs/myofibroblasts, and in situ hybridization showed TN-C mRNA signals in the cells. Activated HSCs and myofibroblasts in culture highly expressed large variants of TN-C. In LI90 cells, sequencing of large variants revealed that the FNIII repeats D and A1/A4, followed by B, were preferentially included.

CONCLUSIONS

TN-C and its variants are produced by HSCs/myofibroblasts, suggesting important roles in liver fibrogenesis.

Deficiency of tenascin-C attenuates liver fibrosis in immune-mediated chronic hepatitis in mice

Tenascin-C (TNC), an extracellular matrix glycoprotein, is upregulated in chronic liver disease. Here, we investigated the contribution of TNC to liver fibrogenesis by comparing immune-mediated hepatitis in wild-type (WT) and TNC-null (TNKO) mice. Eight-week-old BALB/c mice received weekly intravenous injections of concanavalin A to induce hepatitis, and were sacrificed one week after the 3rd, 6th, 9th, and 12th injections. In WT livers, immunohistochemical staining revealed a gradual increase in TNC deposition. TNC mRNA levels also increased sequentially and peaked after the 9th injection. Collagen deposition, stained with picrosirius red, was significantly less intense in TNKO mice than in WT mice, and procollagen I and III transcripts were significantly upregulated in WT mice compared with TNKO mice. Inflammatory infiltrates were most prominent after the 3rd-6th injections in both groups and were less intense in TNKO mice than in WT mice. Interferon-gamma, tumour necrosis factor-alpha, and interleukin-4 mRNA levels were significantly higher in WT mice than in TNKO mice, while activated hepatic stellate cells (HSCs) and myofibroblasts, a cellular source of TNC and procollagens, were more common in WT livers. Transforming growth factor (TGF)-beta1 mRNA expression was significantly upregulated in WT mice, but not in TNKO mice. In conclusion, TNC can promote liver fibrogenesis through enhancement of inflammatory response with cytokine upregulation, HSC recruitment, and TGF-beta expression during progression of hepatitis to fibrosis.

Circulating level of large splice variants of tenascin-C is a marker of piecemeal necrosis activity in patients with chronic hepatitis C

BACKGROUND

It has been reported that histological activity index and piecemeal necrosis are good factors to evaluate the prognosis in patients with chronic hepatitis C (CHC). Thus, there is a need for simple and noninvasive means to assess disease activity and piecemeal necrosis in patients with CHC. In this study, we measured the serum concentrations of large splice variants of tenascin-C (cTN-C) in patients with CHC, and examined their correlation with the degree of inflammatory activity and fibrosis as evaluated in liver biopsy specimens.

METHODS

The serum levels of cTN-C in 150 patients with CHC and 50 healthy volunteers were measured by enzyme-linked immunosorbent. The histology of liver biopsy specimens was also evaluated following the Desmet's grading/staging system and the Ishak's classification. Liver specimens obtained by biopsy were also immunohistochemically evaluated with anti-human tenascin-C antibodies.

RESULTS

Serum cTN-C concentrations were significantly higher in CHC patients than in healthy volunteers (P < 0.0001). The levels of cTN-C showed no significant difference among the fibrosis stages as assessed by the Desmet's grading/staging system and Ishak's classification scores. However, the concentration of cTN-C was significantly correlated with the grade of activity. According to the Ishak's classification, the concentration of cTN-C was increased in proportion to the degree of piecemeal necrosis. Specific immunostaining of cTN-C was observed in limited areas of piecemeal necrosis but not in fibrotic areas.

CONCLUSION

The measurement of serum levels of cTN-C is a useful marker of the activity of CHC, in particular of the degree of piecemeal necrosis.

Co-stimulation of human breast cancer cells with transforming growth factor-beta and tenascin-C enhances matrix metalloproteinase-9 expression and cancer cell invasion

Transforming growth factor-beta (TGF-beta), tenascin-C (TN-C) and matrix metalloproteinases (MMPs) have been demonstrated independently to be associated with disease progression and poor prognosis in patients with breast cancer. The present study explored effects of TGF-beta and TN-C on MMP-9 expression and cancer invasion. An experimental study was designed to analyse MDA-MB-231 breast cancer cells, known for their high invasiveness, after stimulation with TGF-beta1 and/or TN-C. TGF-beta1 stimulated TN-C expression in the cells. Co-stimulation of MDA-MB-231 cells with TN-C and TGF-beta increased MMP-9 expression at both the gene (28-fold) and the protein levels. The in vitro invasion also increased (4-fold). GM6001 inhibited the invasion induced by the co-stimulation. The combined effect of TN-C and TGF-beta resulted in enhanced MMP-9 expression and cancer invasion in vitro.