Hepatic iNOS Expression Research Articles

Vitamin K2 (MK-7) Intercepts Keap-1/Nrf-2/HO-1 Pathway and Hinders Inflammatory/Apoptotic Signaling and Liver Aging in Naturally Aging Rat.

Aging is a naturally occurring physiological process with a deleterious impact on various body organs and humans' well-being. The aging population is increasing worldwide, which imposes the need for the exploration of nutritional options that can intercept the impact of the aging processed on various body organs. Vitamin K2 (VK2) is a fat-soluble vitamin with emerging evidence on its therapeutic merits. In the current study, natural aging induced a significant liver deterioration with a disrupted Keap-1/Nrf-2/HO-1 axis and increased COX-2, iNOS and TNF-α expression and apoptotic and fibrotic changes. VK2 administration, on the other hand, improved the biochemical indices of liver function (total protein, albumin, ALT and AST); the suppressed hepatic expression of Keap-1 and increased the hepatic expression of Nrf-2 with a parallel increase in the hepatic activity of HO-1. Subsequently, the liver content and hepatic expression of TNF-α, COX-2 and iNOS were significantly retracted. In context, the liver content and hepatic expression of the fibrotic biomarkers TGFβ and TIMP significantly retracted as well. Moreover, the TUNEL assay confirmed the retraction of liver apoptotic changes. Of notice, electron transmission microscope examination confirmed the preservation of mitochondrial functions and preservation of the ultra-microscopical structures. In conclusion, the VK2-mediated interception of aging-induced Keap-1/Nrf-2/HO-1 signaling suppressed the hepatic contents of inflammatory and fibrotic biomarkers, as well as apoptotic changes with preservation of the hepatic architectural and functional status. VK2 can be presumed to be an effective nutritional supplement to the aging population to spare the liver, amongst other body organs, against aging-induced deleterious injury.

Blockade of the renin-angiotensin system as a therapeutic target of NAFLD: results of an experimental model of hypercholesterolemia

Abstract Background/Introduction Non-alcoholic fatty liver disease (NAFLD) is often associated with metabolic syndrome (MS) and its components, including systemic arterial hypertension (SAH). In a recently published meta-analysis, the estimated prevalence of SAH in patients with NAFLD was 39.34%. Recently published observational studies have shown that the presence of NAFLD is independently associated with an increased risk of identifying SAH. Therefore, we can infer that we will often have to treat SAH in patients with NAFLD and that potential beneficial effects of the antihypertensive drug, in this context, may influence the choice of the respective drug. Purpose To evaluate the effects of olmesartan in an animal model of NAFLD (hypercholesterolemic rabbits). Methods 34 rabbits divided into 3 groups: control group (CG) n=13, olmesartan group (OG) n=12 and normal control group (NCG) n=9. The NCG received standard chow for laboratory rabbits, the CG and OG received standard chow plus 1% cholesterol. The OG was medicated with olmesartan 1 mg/kg/day throughout the study period (8 weeks), and the three groups were euthanised in the eighth week. Serum levels of glucose, total cholesterol, triglycerides, creatinine, aspartate aminotransferase (AST) and alanine aminotransferase were evaluated at baseline and euthanasia, and liver tissue samples were taken in the euthanasia from the three groups. Haematoxylin-eosin stained slides were analysed based on the histological scoring system for NAFLD, Gomori,s trichrome stained slides were used for further evaluation of fibrosis, and immunostained slides with antibodies anti-nitric oxide synthase inducible (iNOS) for hepatic oxidative stress analysis. Results The steatosis (p=0.013), lobular inflammation (p<0.001), ballooning (p=0.039), and fibrosis (p=0.015) scores were significantly lower in the OG compared to the CG. Similarly, NAFLD activity scores were significantly lower in OG compared to CG. The hepatic expression of iNOS was significantly lower in OG than CG (P=0.001). The serum variables results suggest no direct effect of olmesartan in any of them. Conclusion(s) Olmesartan significantly attenuated hepatic oxidative stress, the development of steatosis, lobular inflammation, ballooning, fibrosis and steatohepatitis. Therefore, it suggests that olmesartan may be considered a potentially suitable option for hypertensive patients with NAFLD. Funding Acknowledgement Type of funding sources: None.

Evaluation of the hepatoprotective effect of curcumin-loaded solid lipid nanoparticles against paracetamol overdose toxicity: Role of inducible nitric oxide synthase

Curcumin (Cur) is a natural compound that exhibited therapeutic effects against various liver injuries however Cur showed poor water solubility and bioavailability. This study aimed to design Cur-loaded solid lipid nanoparticles (SLNs) and to evaluate the hepatoprotective and antioxidant effects in a model of acute hepatotoxicity induced by paracetamol (PCM) overdose compared to the raw Cur and N-acetylcysteine (NAC). SLNs were prepared by emulsion/solvent evaporation method and 32 factorial design was employed. Wistar rats were divided into Control, PCM, PCM + NAC, PCM + raw Cur, and PCM + Cur-SLNs groups and treated orally for 14 days before receiving a single PCM dose. The Cur-loaded SLNs showed high entrapment efficiency % ranging between 69.1 and 92.1%, particle size (PS) between 217 and 506 nm, and zeta potential values between −17.9 and −25.5 mV. The in vivo results revealed that the PCM group exhibited deterioration of liver functions, pathological lesions on the liver tissues, severe oxidative stress, and increases in both the serum and hepatic iNOS levels. Remarkably, the PCM + Cur-SLNs group showed significantly better liver functions and tissue integrity compared to the PCM group. Furthermore, higher reduced glutathione and catalase but lower malondialdehyde and iNOS levels were observed. In conclusion, Cur-loaded SLNs effectively prevented the liver damage induced by PCM overdose through alleviating the oxidative stress and inhibiting the serum and hepatic iNOS expression in an effect comparable to NAC and better than raw Cur.

Hepatic inflammation and liver fibrogenesis: A potential target for the treatment of cystic echinococcosis–associated hepatic injury

To investigate the effect of cystic echinococcosis (CE) on liver damage, we developed a secondary experimental echinococcosis in Swiss mice by intraperitoneal inoculation of viable protoscoleces. Mice were randomly allocated into three groups: Ctrl group, PBS group, and CE group. Mice were euthanized and associated indications were investigated to evaluate inflammatory and fibrotic responses in liver. Hepatic damage and fibrotic reaction were histologically analyzed. The hepatic expression of iNOS, TNF-α, NF-κβ, vimentin, Bcl-2 and CD68 was evaluated by Immunohistochemical examinations. Interestingly, a significant iNOS, TNF-α, NF-κβ, vimentin, Bcl-2 and CD68 increase levels was observed in liver tissue and pericystic layer of hepatic hydatid cyst and correlate with the abundance of collagen and reticulin fibers. These observations could promote a potential target for the treatment of CE–associated hepatic injury.

Protective Effects of Microbiome-Derived Inosine on Lipopolysaccharide-Induced Acute Liver Damage and Inflammation in Mice via Mediating the TLR4/NF-κB Pathway.

This research assessed the anti-inflammatory and hepatoprotective properties of inosine and the associated mechanism. Inosine pretreatment significantly reduced the secretion of several inflammatory factors and serum alanine transaminase (ALT) and aspartate amino transferase (AST) levels in a dose-dependent manner compared with the lipopolysaccharide (LPS) group. In LPS-treated mice, inosine pretreatment significantly reduced the ALT and malondialdehyde (MDA) concentration and significantly elevated the antioxidant enzyme activity. Furthermore, inosine pretreatment significantly altered the relative abundance of the genera, Bifidobacterium, Lachnospiraceae UCG-006, and Muribaculum. Correlation analysis showed that Bifidobacterium and Lachnospiraceae UCG-006 were positively related to the cecal short-chain fatty acids but negatively related to the serum IL-6 and hepatic AST and ALT levels. Notably, inosine pretreatment significantly modulated the hepatic TLR4, MYD88, NF-κB, iNOS, COX2, AMPK, Nfr2, and IκB-α expression. These results suggested that inosine pretreatment alters the intestinal microbiota structure and improves LPS-induced acute liver damage and inflammation through modulating the TLR4/NF-κB signaling pathway.

Alterations in oxidative metabolism in liver of female rats: Effects of long-term vitamin A deficiency

Background: The latest estimate by 5 UN agencies is that 821 million people globally are undernourished, which puts them at risk of vitamin and other nutrient deficiencies. Vitamin A deficiency remains a widespread public health problem among women and children in the developing world the role of vitamin A and its active metabolites in pathways involved in antioxidant protection and in the inhibition of important pathways that promote oxidative stress. Objectives: Determine if vitamin A deficiency could influence oxidative metabolism in 6-month-old female wistar rats. Materials and Methods: Determine the concentration of carbonyl proteins, as a marker of protein oxidation; TBARS, as a lipoperoxidation marker; and nitrotyrosine as a marker of oxidative stress dependent on nitric oxide. Quantify the expression of CAT, SOD, eNOS and iNOS in the liver and wistar rats deficient in vitamin A for 6 months. Results: An increase in the concentration of carbonyl protein and nitrotyrosine in the liver tissue deficient in vitamin A is observed. The expression of SOD, eNOS and iNOS decreased in the group with a private diet of vitamin A. From the regression analysis a positive correlation was established between hepatic retinoic acid levels and gene expression of eNOS, iNOS and SOD. A positive correlation between serum retinoic acid levels and gene expression of eNOS and iNOS was also observed. Conclusions: It is possible to ratify the relationship between the development of stress and vitamin A levels; improving the understanding of hepatic metabolism and its response to the absence of this vitamin.

Bisphenol A-induced oxidative stress, hepatotoxicity and altered estrogen receptor expression in Labeo bata: impact on metabolic homeostasis and inflammatory response

Bisphenol A (BPA), a weak estrogenic endocrine disruptor and a well-known plasticizer, has the potential to perturb diverse physiological functions; however, its impact on immune and metabolic function in aquatic vertebrates is relatively less understood. The present study aims to investigate the impact of BPA on hepatotoxicity, metabolic and immune parameters vis-à-vis estrogen receptor expression modulation in a freshwater teleost, Labeo bata (Cyprinidae, Cypriniformes). The 96-h median lethal concentration of BPA in L. bata has been determined as 4.79 mg/L. Our data demonstrate that congruent with induction of plasma vitellogenin (VTG), chronic exposure to sub-lethal BPA (2 and 4 μM/L) attenuates erythrocyte count, hemoglobin concentration, packed cell volume, mean corpuscular hemoglobin, but not leukocyte number. Further, a significant increase in MDA, concomitant with diminished catalase and heightened GST activity corroborates well with hepatic dystrophic changes, appearance of fatty liver (macrovesicular steatosis) and elevated serum lipids (triglyceride, cholesterol, LDL, VLDL) in BPA-treated groups. Interestingly, a differential regulation of estrogen receptor (ER) subtypes at transcript and protein level signifies negative influence of BPA on hepatic ERα/ERβ homeostasis in this species. While at a lower dose it promotes Akt phosphorylation (activation), BPA at the higher dose attenuates ERK1/2 phosphorylation (activation), suggesting potential alteration in insulin sensitivity. Importantly, dose-dependent decrease in hepatic TNF-α, IL-1β, iNOS (NOS2) expression and nitric oxide (NO) level corresponds well with progressive decline in p-NF-κB, p-p38 MAPK, albeit with differential sensitivity, in BPA-exposed groups. Collectively, BPA exposure has wide-spread negative influence on hematological, biochemical and hepatic events in this species.

Transient Expression of Reck Under Hepatic Ischemia/Reperfusion Conditions Is Associated with Mapk Signaling Pathways.

In this study, we demonstrated the involvement of matrix metalloproteinases (MMPs) in hepatic ischemia/reperfusion (I/R) injury. Our aim is to evaluate the impact of reperfusion on I/R-related changes in RECK, an MMP modulator, and mitogen-activated protein kinase (MAPKs) pathways (ERK, p38, and JNK). Male Wistar rats were either subjected to 60 min partial-hepatic ischemia or sham-operated. After a 60 min or 120 min reperfusion, liver samples were collected for analysis of MMP-2 and MMP-9 by zymography and RECK, TIMP-1, and TIMP-2 content, MAPKs activation (ERK1/2, JNK1/2, and p38), as well as iNOS and eNOS by Western blot. Serum enzymes AST, ALT, and alkaline-phosphatase were quantified. A transitory decrease in hepatic RECK and TIMPs was associated with a transitory increase in both MMP-2 and MMP-9 activity and a robust activation of ERK1/2, JNK1/2, and p38 were detected at 60 min reperfusion. Hepatic expression of iNOS was maximally upregulated at 120 min reperfusion. An increase in eNOS was detected at 120 min reperfusion. I/R evoked significant hepatic injury in a time-dependent manner. These findings provide new insights into the underlying molecular mechanisms of reperfusion in inducing hepatic injury: a transitory decrease in RECK and TIMPs and increases in both MAPK and MMP activity suggest their role as triggering factors of the organ dysfunction.

A preventive effect of the combination of albendazole and pomegranate peel aqueous extract treatment in cystic echinococcosis mice model: An alternative approach

To investigate the preventive effect of the combination of albendazole (ABZ) and pomegranate peel aqueous extract (PGE) treatment in cystic echinococcosis, we assess in vivo the antihydatic and the anti-inflammatory effects of the combination of ABZ/ PGE in cystic echinococcosis mice model. To evaluate the in vivo efficacy, mice were inoculated intraperitoneally with viable protoscolices and then treated with ABZ and/or PGE during cystic echinococcosis development. Mice were randomly allocated into eight groups: ABZ/CE group, PGE/CE group, (ABZ+PGE)/CE group, CE group, and control groups (Ctrl, PBS, ABZ, and PGE groups). Drugs in diverse treated groups were orally administered daily during CE development for two months. Mice were then euthanized and associated indications were investigated to evaluate the therapeutic efficacy. Cyst development and hepatic damage were macroscopically and histologically analyzed. The hepatic expression of iNOS, TNF-α, NF-κβ, vimentin, and CD68 was examined. Interestingly, the association of ABZ and PGE enhanced a significant reduction of the rate of hydatid cyst growth inhibition in comparison to the infected or ABZ-treated groups. This effect was strongly related to the histological structure of liver improvement. A significant iNOS, TNF-α, NF-κβ, vimentin, and CD68 decrease expression was observed in liver tissue of (ABZ+PGE)-treated group compared with infested and ABZ-treated groups. PGE treatment indicates a significant beneficial additive antihydatic effect with a reduction of the liver side effects. The combination of albendazole and PGE treatment is more efficient and suggests its potential preventive value against Echinococcus granulosus infection.

Estradiol-mediated regulation of hepatic iNOS in obese rats: Impact of Src, ERK1/2, AMPKα, and miR-221.

This study aimed to investigate in vivo effects of estradiol on the regulation of hepatic inducible nitric oxide synthase (iNOS) expression in the high fat (HF) diet-induced obesity. Also, we aimed to investigate whether activation of the extracellular signal-regulated kinase (ERK1/2), adenosine monophosphate-activated protein kinase (AMPK), Src kinase, and miR-221 is involved in estradiol-mediated regulation of iNOS in the liver of obese male Wistar rats. Male Wistar rats were fed a standard laboratory diet or a HF diet for 10 weeks. Half of HF rats were treated with estradiol intraperitoneally (40 μg/kg), whereas the other half were placebo-treated 24 H before euthanasia. Results show that estradiol treatment of HF rats decreased hepatic iNOS mRNA (P<0.05) and protein expression (P<0.01), the protein levels of p65 subunit of nuclear factor κB (P<0.05) and ERα (P<0.05), ERK1/2 phosphorylation (P<0.001), and ERα/Src kinase association (P<0.05). By contrast, hepatic Src protein level (P<0.05), AMPKα phosphorylation (P<0.05), and miR-221 expression (P < 0.05) were increased in HF rats after estradiol treatment. Our results indicate that estradiol in vivo regulates hepatic iNOS expression in obese rats via molecular mechanisms involving ERK1/2, AMPK, Src, and miR-221 signaling.

Protective Effects of Morus Root Extract (MRE) Against Lipopolysaccharide-Activated RAW264.7 Cells and CCl4-Induced Mouse Hepatic Damage

Background/Aims: Inflammation is one of the main contributors to chronic diseases such as cancer. It is of great value to identify the potential activity of various medicinal plants for regulating or blocking uncontrolled chronic inflammation. We investigated whether the root extract of Morus australis possesses antiinflammatory and antioxidative stress potential and hepatic protective activity. Methods: The microwave-assisted extractionwere was used to prepare the ethanol extract from the dried root of Morus australis (MRE), including polyphenolic and flavonoid contents. Lipopolysaccharide (LPS)-stimulated RAW264.7 cells was examined the anti-inflammatory and anti-oxidative potential of MRE. CCl₄-induced mouse hepatic damage were performed to detect the hepatic protective potential in vivo. Immunohistochemistry (IHC) and western blot assays were used to detect target proteins. Results: MRE contained approximately 23% phenolic compounds and 3% flavonoids. The major flavonoid component of MRE was morusin. MRE and morusin inhibited lipopolysaccharide-induced production of nitrite and prostaglandin E2 in RAW264.7 cells. MRE and morusin also suppressed the formation of intracellular reactive oxygen species and the expression of iNOS and COX-2. In an in vivo study, a thiobarbituric acid reactive substances assay showed that MRE inhibited CCl₄-induced oxidative stress and expression of nitrotyrosine. MRE also decreased CCl₄-induced hepatic iNOS and COX-2 expression, as well as CCl₄-induced hepatic inflammation and necrosis in mice. Conclusion: MRE exhibited antiinflammatory and hepatic protective activity.

Improved hepatic γ-tocopherol status limits oxidative and inflammatory stress-mediated liver injury in db/db mice with nonalcoholic steatohepatitis

γ-Tocopherol (γ-T) and its physiological metabolite γ-carboxyethyl-hydroxychroman (γ-CEHC) exhibit antioxidant and anti-inflammatory activities. We hypothesized that improved hepatic γ-T status would protect against NASH in leptin-resistant db/db mice. Wild-type mice were fed a diet without γ-T, and db/db mice were fed the same diet supplemented with or without γ-T for 8 wk. Hepatic γ-T and γ-CEHC levels were increased (P < .05) compared with db/db controls. Serum ALT and insulin resistance, which were otherwise increased in db/db controls, were 33–38% lower in db/db mice fed γ-T. Increased hepatic lipid peroxidation in db/db mice was attenuated by dietary γ-T, which occurred without increasing hepatic Nrf2 mRNA expression. However, γ-T attenuated hepatic iNOS, MCP-1, TNF-α and CRP expression. Histological assessment showed γ-T-mediated improvements in overall hepatic architecture, specifically by limiting hepatic steatosis. These findings demonstrate that improvements in hepatic γ-T status protect against liver injury during NASH by reducing inflammation and oxidative stress.

Seabuckthorn berry polysaccharide extracts protect against acetaminophen induced hepatotoxicity in mice via activating the Nrf-2/HO-1-SOD-2 signaling pathway

BackgroundOxidative stress is concomitant with acetaminophen (APAP)-induced hepatotoxicity, which has been highlighted as therapeutic targets for such diseases. The berries of Seabuckthorn (Hippophae rhamnoides L.) have been traditionally used in Tibetan medicine for thousands of years. The effect of Seabuckthorn berry polysaccharide on drug- induced liver injury (DILI) has not yet been elucidated. PurposeThis study aims to investigate the protective effects and mechanisms of Seabuckthorn polysaccharide (SP) against APAP-induced hepatotoxicity. Study designSixty C57BL/6 mice were randomly divided into six groups (n = 10 per group), namely the control group (Ctrl), APAP-induced-liver injury group (APAP), NAC pretreated group (NAC), 100 mg/kg SP pretreated group (APAP/SP100), 200 mg/kg SP pretreated group (APAP/SP200) and 200 mg/kg SP pretreated group without APAP challenge (SP200). SP was given orally to mice for 30 consecutive days prior to APAP exposure (300 mg/kg). NAC (150 mg/kg) was administrated 1 h before APAP challenge. MethodsALT and AST were detected 16 h after APAP treatment; Hepatic expression of GSH, SOD, NO, iNOS and GSH-Px were examined. The expression of p-JNK, Bcl-2/Bax, p62, Keap-1 and SOD-2 was detected by Western blotting. The expression of Nrf-2 and its target genes HO-1, GCLC and NQO-1 were analyzed by RT-PCR and Western blotting. ResultsPretreatment with SP led to decreased levels of ALT and AST in APAP mice, without affecting APAP metabolism. This was accompanied by diminished liver injuries, increased levels of GSH and GSH-Px, reduced NO and iNOS expression. SP increased the activity of SOD as well as SOD-2 expression in APAP mice. SP suppressed APAP-induced JNK phosphorylation and increased the ratio of Bcl-2/Bax. Furthermore, SP decreased the expression of Keap-1 and increased the nuclear expression of Nrf-2. The expression of Nrf-2 target gene HO-1 was increased by SP pretreatment in APAP mice. ConclusionSP alleviates APAP-induced hepatotoxicity. The protective effects of SP are associated with the activation of the Nrf-2/HO-1-SOD-2 signaling pathway.

Heat-Cured Methyl Methacrylate Induces Increased Expression of HSP70 and iNOS in the Liver

Introduction: Exposure to methyl methacrylate (MMA), which is a widely used monomer in dental and medical fields, has been shown to be associated with adverse health effects on liver. Aim: This study aims to evaluate the mechanism toxic effect of MMA on liver, via investigating alterations in the expression levels of inducible nitric oxide synthase (iNOS) and heat shock protein70 (HSP70) in the liver, subsequent to the oral administration of MMA in rats. Methods: 20 SpragueDawley female rats were randomly selected and divided into two groups: control group, and experimental group. The experimental group was orally administered 120 mg/kg of MMA daily 5 times per week for four weeks. Changes in the expression of HSP70 and iNOS in the liver tissue was investigated using Immunohistochemistry technique. Results: Exp group had statistcaly higher hepatic expression of iNOS (p &gt; 0.01) in comparison to the control group, by approximately three folds. Similarly, rat hepatocytes in the experimental group showed statistically significant (p &gt; 0.01) increase, by approximately 15 folds, in the expression of HSP70 compared to that in the control group. Conclusion: The presented data suggest that exposure to MMA might cause liver injury as indicated by the prominanat elevation of the oxidative stress biomarker iNOS and the biological stress biomarker HSP70.

Down-regulation of nuclear HMGB1 reduces ischemia-induced HMGB1 translocation and release and protects against liver ischemia-reperfusion injury

Hepatocyte-specific HMGB1 deletion has been found to worsen the injury and inflammation in liver ischemia-reperfusion injury (IRI), highlighting a role for intracellular HMGB1 in cellular protection. Down-regulation of nuclear HMGB1 by small interfering RNA (siRNA) might not only decrease its injurious extracellular role by reducing its release but also serve to maintain its beneficial intracellular role, thus protecting against IRI. We established a non-lethal liver IRI model in mice via segmental hepatic warm ischemia for 1 h and reperfusion for 6 h. HMGB1-siRNA achieved a reduction of ~60–70% in the nuclear HMGB1 expression in the liver at 48 h post-treatment. Knockdown of nuclear HMGB1 expression dramatically reduced both the degree of nuclear-cytoplasmic translocation of HMGB1 during hepatic ischemia and of HMGB1 release after hepatic reperfusion, resulting in significant preservation of liver function and a marked reduction in pathological damage. Also, HMGB1-siRNA pretreatment markedly inhibited the increases in hepatic expression of TLR4, TLR2, RAGE, TNF-α, IL-1β, IL-6, MCP-1, iNOS, and COX-2 seen in control mice after hepatic reperfusion. We demonstrated for the first time that down-regulation of nuclear HMGB1 reduces ischemia-induced HMGB1 release and protects against liver IRI, which is helpful for better understanding the role of HMGB1 in organ IRI.

Thymoquinone mitigate ischemia-reperfusion-induced liver injury in rats: a pivotal role of nitric oxide signaling pathway.

Oxidative and nitrosative stress-induced endothelial cell damage play an essential role in the pathogenesis of hepatic ischemia-reperfusion (IR) injury. IR is associated with reduced eNOS expression and exacerbated by superimposed stress. NOSTRIN induces intracellular endothelial nitric oxide synthase (eNOS) translocation and inducible nitric oxide synthase (iNOS) increases nitric oxide (NO) production. Our aim was to assess hepatic expression of iNOS, eNOS, and NOSTRIN in IR with or without N-acetylcysteine (NAC) or thymoquinone (TQ) pretreatment and to compare their hepatoprotective effects. Surgical induction of IR was performed by occlusion of hepatic pedicle for 30min with mini-clamp and reperfused for 30min. The effects of TQ (20mg/kg/day) or NAC (300mg/kg/day) administered orally for 10days were evaluated by serum ALT and AST, oxidative stress parameters, NO production, and histopathological analysis. Also, localization and expression of iNOS, eNOS, and NOSTRIN were assessed by immunofluorescence. TQ or NAC pretreatment significantly decreased elevated serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and myeloperoxidase (MPO) activities, malondialdehyde (MDA) level, and NO production. In addition, they restored the depleted GSH content and alleviated histopathological changes. Furthermore, they up-regulated eNOS and down-regulated iNOS and NOSTRIN expressions. TQ exerts its hepatoprotective effect, at least in part, by nitric oxide signaling pathway through modulation of iNOS, eNOS, and NOSTRIN expressions as well as suppression of oxidative stress.

Antihydatic and immunomodulatory effects of Punica granatum peel aqueous extract in a murine model of echinococcosis.

To investigate the effect of pomegranate peel aqueous extract (PGE) on the development of secondary experimental echinococcosis and on the viability of Echinococcus granulosus protoscoleces, and the immunomodulatory properties of PGE. Swiss mice were inoculated intraperitoneally with viable protoscoleces. Then, PGE was orally administered daily during cystic echinococcosis development. Cyst development and hepatic damage were macroscopically and histologically analyzed. The production of nitric oxide and TNF-α was assessed in plasma and the hepatic expression of iNOS, TNF-α, NF-κB and CD68 was examined. Moreover, protoscoleces were cultured and treated with different concentrations of PGE. It was observed that invitro treatment of protoscoleces caused a significant decrease in viability in a PGE-dose-dependent manner. Invivo, after treatment of cystic echinococcosis infected mice with PGE, a significant decrease in nitric oxide levels (P<0.0001) and TNF-α levels (P<0.001) was observed. This decline was strongly related to the inhibition of cyst development (rate of hydatid cyst growth inhibition=63.08%) and a decrease in CD68 expression in both the pericystic layer of hepatic hydatid cysts and liver tissue (P<0.0001). A significant diminution of iNOS, TNF-α and NF-κB expression was also observed in liver tissue of treated mice (P<0.0001). Our results indicate an antihydatic scolicidal effect and immunomodulatory properties of PGE, suggesting its potential therapeutic role against Echinococcus granulosus infection.

Silymarin alleviates hepatic oxidative stress and protects against metabolic disorders in high-fat diet-fed mice

ABSTRACTSilymarin is a potent antioxidant medicine and has been widely used for the treatment of liver diseases over 30 years. Recent studies suggest that silymarin may benefit patients with glucose intolerance. However, the mechanism underlying the action of silymarin is not clarified. The aim of this work was to assess the impact of silymarin on glucose intolerance in high-fat diet (HFD)-fed mice, and explore the potential therapeutic mechanisms. C57BL/6 mice were fed with HFD for 12 weeks, randomized, and treated orally with vehicle saline or silymarin (30 mg/kg) daily for 30 days. We found that silymarin significantly improved HFD-induced body weight gain, glucose intolerance, and insulin resistance in mice. Silymarin treatment reduced HFD-increased oxidative stress indicators (reactive oxygen species, lipid peroxidation, protein oxidation) and restored HFD-down-regulated activities of antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase) in the plasma and/or liver of the HFD-fed mice. Furthermore, silymarin decreased HFD-up-regulated hepatic NADPH oxidase expression and NF-κB activation in mice. Additionally, silymarin treatment mitigated HFD-increased plasma IL-1β, TNF-α levels, and HFD-enhanced hepatic NO, TLR4, and iNOS expression in mice. These novel data indicate that silymarin has potent anti-diabetic actions through alleviating oxidative stress and inflammatory response, partially by inhibiting hepatic NADPH oxidase expression and the NF-κB signaling.

Hepatoprotective activity of viscosine is mediated by attenuation of hepatic macrophages and iNOS expression in CCl4-intoxicated rats.

This study investigated the molecular mechanism(s) of the protective effects of a C-alkylated flavonoid, viscosine on an animal model of CCl4-induced hepatotoxicity. Viscosine at 20, 50 and 100 mg kg-1 was orally administered in a dose dependent manner per day for 3 days before the CCl4 (1 : 1 v/v in olive oil, 1 ml kg-1) treatment and 2 days after the treatment. Hepatoprotection was assessed in terms of reduction in serum enzyme activities (ALT, AST, and ALP) that occur after CCl4 injury, and by histopathology and immunohistochemistry. The rise in serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) in CCl4-intoxicated rats was markedly suppressed by viscosine in a concentration dependent manner. The decrease in the activity of hepatic antioxidant enzyme, SOD, was significantly prevented by viscosine, likewise gradually the levels of MDA and GSH were also normalized compared to silymarin. Viscosine also reduced the CCl4-induced damaged area from 2% to 0% as assessed by histopathology and prevented the mixed inflammatory infiltrate. Viscosine attenuated the inflammation in the liver around the injured central vein region by downregulating the CCl4 induced activation of hepatic CD68+ macrophages, thereby reducing their number as well. The expression of inducible nitric oxide synthase (iNOS) was more potentially suppressed by viscosine compared to the FDA approved positive control silymarin. The results of this study indicate that viscosine could be effective in protecting the liver from acute CCl4-induced injury. The hepatoprotective mechanisms of viscosine may be related to the free radical scavenging and attenuation of oxidative stress, as well as to the inhibition of inflammatory response in the liver. Here, we are proposing a novel mechanism of action of viscosine and suggesting that it may be a safe and better in vivo antioxidant.

Hemodynamic Effects of the Non-Peptidic Angiotensin-(1-7) Agonist AVE0991 in Liver Cirrhosis.

Background & AimsAlthough in cirrhosis with portal hypertension levels of the vasoconstrictor angiotensin II are increased, this is accompanied by increased production of angiotensin (Ang)-(1–7), the endogenous ligand of the Mas receptor (MasR), which blunts hepatic fibrosis and decreases hepatic vascular resistance. Therefore, we investigated the effects of the non-peptidic Ang-(1–7) agonist, AVE0991, in experimental cirrhosis.MethodsCirrhosis was induced by bile duct ligation (BDL) or carbon tetrachloride (CCl4) intoxication. The coloured microsphere technique assessed portal and systemic hemodynamic effects of AVE0991 in vivo. Hepatic expression of eNOS, p-eNOS, iNOS, JAK2, ROCK and p-Moesin were analyzed by western blots. Activities of ACE and ACE2 were investigated fluorometrically. Moreover, fibrosis was assessed in BDL rats receiving AVE0991.Results In vivo, AVE0991 decreased portal pressure (PP) in both rat models of cirrhosis. Importantly, systemic effects were not observed. The hepatic effects of AVE0991 were based on upregulation of vasodilating pathways involving p-eNOS and iNOS, as well as by downregulation of the vasoconstrictive pathways (ROCK, p-Moesin). Short-term treatment with AVE0991 decreased the activity of ACE2, long-term treatment did not affect hepatic fibrosis in BDL rats.ConclusionsThe non-peptidic agonist of Ang-(1–7), AVE0991, decreases portal pressure without influencing systemic pressure. Thus, although it does not inhibit fibrosis, AVE0991 may represent a promising new therapeutic strategy for lowering portal pressure.