The roles played by crucial free radicals like lipid free radicals, nitric oxide, and enzymes NOS and NADPH in CCl(4)-induced acute liver injury of mice

Iron overload induced by diphenylamine triggers reactive oxygen species and apoptosis in the spleen of pregnant rats and their fetuses

Diphenylamine (DPA) is an aniline derivative, used widely as an industrial antioxidant, dye mordant, and agricultural fungicide. DPA was reported as hazardous to mammals both acutely and chronically, however little is known about the toxicity of DPA and its derivatives during pregnancy. This study aimed to evaluate and explain the possible mechanism of toxicity induced by DPA on blood and spleen, as a fundamental hematopoietic target organ, in pregnant rats and their fetuses. Pregnant rats were orally administrated distilled water, corn oil, and/or DPA (400 mg/kg b.wt) from the 5th to 19th day of gestation. DPA-induced spleen toxicity was mirrored by significant upregulation of programmed death-1 (PD-1) protein expression and an increase in the percentage of apoptotic cells and a decrease in their proliferating capacity. These results have been confirmed through marked G0/G1 cell-cycle arrest that was observed by flow cytometric analysis of spleen cells. Moreover, the contents of reactive oxygen species and iron in the spleen tissue were significantly higher than that of the control group. DPA resulted in severe anemia, decreased hemoglobin and hematocrit, thrombocytopenia and leukopenia in addition to significant changes in differential leukocytic count of both mothers and fetuses. Evidently, DPA triggered serious pathological changes in the spleen tissue of both mothers and fetuses and the histochemical examination revealed a significant increase in iron expression. In conclusion, these results implicate the hemato- and splenotoxicity of DPA and the possible role of oxidative stress and apoptosis in DPA-induced toxicity in the spleen of pregnant rats and their fetuses. This in-turn suggests the urgent need to reduce exposure to DPA as possible as it can.

Evening primrose oil attenuates oxidative stress, inflammation, fibrosis, apoptosis, and ultrastructural alterations induced by metanil yellow in the liver of rat: a histological, immunohistochemical, and biochemical study

The food color metanil yellow (Myl) is hazardous to several body systems. Evening primrose oil (EPO) was reported to have anti-inflammatory and anti-oxidant properties. The present work investigated the impact of Myl on the hepatic structure and function of rats and evaluated the protective effect of EPO. Forty adult male rats were divided into four groups: control, EPO (5 g/kg/day), Myl (200 mg/kg/day), and EPO- Myl group. Myl significantly increased liver enzymes, advanced glycation end products (AGE), oxidative stress parameters, pro-inflammatory cytokines, nuclear factor kappa B (NF-κB), and inducible nitric oxide synthase (iNOS). Blood vessels in the liver were dilated and congested, with cellular infiltration around them and associated with fibrosis. The hepatocytes were vacuolated and had dark nuclei. The immunohistochemical expression of iNOS, glial fibrillary acidic protein (GFAP), and Bax was significantly elevated. Ultrastructurally, the hepatocytes showed lipid droplets, irregular condensed nuclei with widened perinuclear space, dilated rER, mitochondria with destructed cristae, and multiple vacuoles. Dilated congested blood sinusoids and collagen fiber bundles were seen between hepatocytes. Interestingly, these alterations were less pronounced in rats co-administrated with EPO and Myl. In conclusion, EPO can protect liver against the toxic effects of Myl due to its anti-inflammatory and anti-oxidant activities.

Therapeutic role of nitroglycerin against copper-nitrilotriacetate induced hepatic and renal damage

Earlier we have shown that exposure to copper-nitrilotriacetate (Cu-NTA) manifests toxicity by generating oxidative stress and potent induction of proliferative reaction in the liver and kidney. In the study, we look at the impact of nitroglycerin (GTN) administration on Cu-NTA-induced oxidative stress and hyperproliferative response in the liver and kidney. GTN administration intraperitoneally to male Wistar rats after Cu-NTA administration intraperitoneally caused substantial protection against Cu-NTA-induced tissue injury, oxidative stress and hyperproliferative response. Cu-NTA administration at a dose of 4.5 mg/kg body weight produces significant ( p < .001) elevation in biochemical parameters including aspartate aminotransferase (AST), alanine aminotransferase (ALT), blood urea nitrogen (BUN) and creatinine (CREA) with a concomitant increase in microsomal lipid peroxidation. Along with these alterations, we discovered a substantial increment in [3H]thymidine incorporation into hepatic and renal DNA synthesis ( p < .001). Cu-NTA-induced tissue damage and lipid peroxidation in hepatic and renal tissues were inhibited by GTN treatment in a dose-dependent manner ( p < .05–0.001). Furthermore, GTN can suppress the hyperproliferative response elicited by Cu-NTA by down-regulating the rate of [3H]thymidine incorporation into hepatic and renal DNA ( p < .01–0.001). Protective effect of GTN against Cu-NTA was also confirmed by histopathological changes in liver and kidney. This result suggests that GTN may serve as a scavenger for reactive oxygen species (ROS) and reduces toxic metabolites of Cu-NTA, thereby avoiding tissue injury and oxidative stress. Further, administration of NO inhibitor, NG-Nitroarginine methyl ester (L-NAME), exacerbated Cu-NTA induced oxidative tissue damage and cell proliferation. Overall, GTN reduces Cu-NTA-induced tissue damage, oxidative stress, and proliferative response in the rat liver and kidney, according to these findings. On the basis of the above results, present study suggests that GTN may be a potential therapeutic agent for restoration of oxidative damage and proliferation to liver and kidney.

A review of therapeutic potentials of turmeric (Curcuma longa) and its active constituent, curcumin, on inflammatory disorders, pain, and their related patents

Turmeric (Curcuma longa) and its constituent, curcumin, have been used for their therapeutic properties for a long time. Most of the medicinal impacts of turmeric and curcumin might be attributed to their anti-inflammatory, antinociceptive, and antioxidant effects. In the present review, the preventive and therapeutic potentials of turmeric and its active constituent, curcumin, on inflammatory disorders and pain as well as patents related to their analgesic and anti-inflammatory effects, have been summarized to highlight their value on human health. A literature review was accomplished in Google Scholar, PubMed, Scopus, Google Patent, Patentscope, and US Patent. Several documents and patents disclosed the significance of turmeric and curcumin to apply in several therapeutic, medicinal, and pharmaceutical fields. These phytocompounds could be applied as a supplementary therapy in phytotherapy, inflammatory disorders such as arthritis, inflammatory bowel diseases, osteoarthritis, psoriasis, dermatitis, and different types of pain including neuropathic pain. However, because of inadequate clinical trials, further high-quality studies are needed to firmly establish the clinical efficacy of the plant. Consistent with the human tendency to the usage of phytocompounds rather than synthetic drugs, particular consideration must be dedicated to bond the worth of turmeric and curcumin from basic sciences to clinical applications.

Sheltering proteins from protease-mediated degradation and a de novo strategy for preventing acute liver injury

Restoring protein functions or supplying proteins is considered one of the most powerful therapeutic strategies for many diseases, but it is mainly limited by the denaturation of proteins during encapsulation and degradation by proteases during in vivo delivery, and limits its delivery. Herein, by encapsulating a protein (catalase, an enzyme) in a hexahistidine-metal assembly (HmA) via a de novo strategy under mild conditions, we demonstrated that HmA could maintain the bioactivity of the enzyme, protect the enzyme from proteinase degradation, and deliver the encapsulated protein for the prevention of disease in an acute liver injury model.

Hepatoprotective effects of Psidium guajava on mitochondrial enzymes and inflammatory markers in carbon tetrachloride-induced hepatotoxicity

OBJECTIVE

The present investigation was aimed to evaluate the hepatoprotective potential of ethanolic extract of Psidium guajava (P. guajva) and its isolated quercetin fraction on carbon tetrachloride (CCl₄)-induced hepatotoxicity.

MATERIALS AND METHODS

The rats were divided into 6 groups and each group contained 6 rats. CCl₄ (1.5 ml/kg b.w.) was used to induce the hepatotoxicity. Ethanolic extract of P. guajava (300 mg/kg b.w.), isolated quercetin fraction (20 mg/kg b.w.) were used as a treatment and silymarin (25 mg/kg b.w.) was used as a standard drug. After the study period, the liver tissues were collected and evaluate the levels of liver functional markers, mitochondrial enzymes, histopathological analysis and the expressions of inflammatory markers.

RESULTS

The levels of liver functional markers were increased and protein, albumin and A/G ratio levels were decreased and the decreased levels of mitochondrial enzymes were noted in CCl₄-induced rats and the levels were restored near to normal significantly when the administration ethanolic extract of P. guajava, isolated quercetin fraction and silymarin. The normal architecture of liver tissues were altered and the mRNA expressions were up-regulated in CCl₄-induced rats and the liver tissues were normalized and the mRNA and protein expressions were down-regulated near to normal significantly when the administration of ethanolic extract of P. guajava, isolated quercetin fraction and silymarin.

CONCLUSION

From these results, the isolated quercetin fractions have better activity than that of the ethanolic extract of P. guajava leaves. Hence, the isolated quercetin may be used as the safest drug for hepatotoxicity in future.

Inhibition of CYP2E1 and activation of Nrf2 signaling pathways by a fraction from Entada africana alleviate carbon tetrachloride-induced hepatotoxicity

Entada africana is used in non-conventional medicine for the management of liver ailments. A fraction, designated EaF10 (methylene chloride/methanol 90:10, v/v) with promising hepatoprotective activity has been isolated. Since the mechanisms underlying EaF10 hepatoprotective action remain unknown, this study was undertaken to investigate the anti-hepatotoxic mechanism of the fraction against carbon tetrachloride (CCl4)-induced hepatotoxicity and its antioxidant properties. Antioxidant activities of EaF10 were assessed through four chemical antioxidant assays and its anti-hepatotoxic effect evaluated in vivo and in vitro by post-treatment (25 or 100 mg/Kg) or co-treatment (6.25-100 μg/mL) in CCl4-intoxicated mice and normal human liver cells line L-02 hepatocytes respectively; and biochemical and molecular parameters assessed respectively by spectrophotometry, and by quantitative real-time polymerase chain reaction and western blot analysis. EaF10 exhibited strong antioxidant activities correlated with its polyphenol content. Serum levels of alanine/aspartate aminotransferase (AST/ALT) and nitrite oxide, liver contents of glutathione (GSH) protein carbonylation and malondialdehyde (MDA), liver activities of catalase (CAT), glutathione-S-transferase (GST) and superoxide dismutase (SOD) and cell viability showed the anti-hepatotoxic effect of EaF10, supported by histopathological observations. The fraction decreased the protein level of Cytochrome P450 2E1 (CYP2E1) and Kelch-like ECH-associated protein-1 (Keap-1), induced nuclear translocation of Nuclear factor-erythroid 2-related factor-2 (Nrf2) coupled to an increase of the mRNA levels of CAT, SOD1 and GST in CCl4-intoxicated L-02 hepatocytes. These findings evidenced that the studied plant fraction possesses a strong antioxidant capacity and prevents CCl4-induced hepatotoxicity, likely through inhibition of CYP2E1 and activation of the Nrf2 signaling pathway.

In-depth hepatoprotective mechanistic study of Phyllanthus niruri: In vitro and in vivo studies and its chemical characterization

Phyllanthus niruri L. is a widespread tropical plant which is used in Ayurvedic system for liver and kidney ailments. The present study aims at specifying the most active hepatoprotective extract of P. niruri and applying a bio-guided protocol to identify the active compounds responsible for this effect. P. niruri aerial parts were extracted separately with water, 50%, 70% and 80% ethanol. The cytoprotective activity of the extracts was evaluated against CCl₄-induced hepatotoxicity in clone-9 and Hepg2 cells. Bioassay-guided fractionation of the aqueous extract (AE) was accomplished for the isolation of the active compounds. Antioxidant activity was assessed using DPPH (1, 1-diphenyl-2-picrylhydrazyl) radical scavenging method and ferric reducing antioxidant power (FRAP). The in vivo hepatoprotective activity of AE was evaluated in CCl₄-induced hepatotoxicity in rats at different doses after determination of its LD₅₀. Pretreatment of clone-9 and Hepg2 with different concentrations of AE (1, 0.1, 0.01 mg/ml) had significantly reduced the levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) against CCl₄ injures, and restored the activity of the natural antioxidants; glutathione (GSH) and superoxide dismutase (SOD) towards normalization. Fractionation of AE gave four fractions (I-IV). Fractions I, II, and IV showed a significant in vitro hepatoprotective activity. Purification of I, II and IV yielded seven compounds; corilagin C1, isocorilagin C2, brevifolin C3, quercetin C4, kaempferol rhamnoside C5, gallic acid C6, and brevifolin carboxylic acid C7. Compounds C1, C2, C5, and C7 showed the highest (p< 0.001) hepatoprotective potency, while C3, C4, and C6 exhibited a moderate (p< 0.001) activity. The AE exhibited strong antioxidant DPPH (IC₅₀ 11.6 ± 2 μg/ml) and FRAP (79.352 ± 2.88 mM Ferrous equivalents) activity. In vivo administration of AE in rats (25, 50, 100 and 200 mg/kg) caused normalization of AST, ALT, alkaline phosphatase (ALP), lactate dehydrogenase (LDH), total cholesterol (TC), triglycyrides (TG), total bilirubin (TB), glucose, total proteins (TP), urea and creatinine levels which were elevated by CCl₄. AE also decreased TNF-α, NF-KB, IL-6, IL-8, IL10 and COX-2 expression, and significantly antagonizes the effect of CCl₄ on the antioxidant enzymes SOD, catalase (CAT), glutathione reductase (GR), and glutathione peroxidase (GSP). The histopathological study also supported the hepatoprotective effect of AE. P. niruri isolates exhibited a potent hepatoprotective activity against CCl₄-induced hepatotoxicity in clone-9 and Hepg2 cell lines through reduction of lipid peroxidation and maintaining glutathione in its reduced form. This is attributable to their phenolic nature and hence antioxidative potential.

DPP4 Inhibitor Attenuates Severe Acute Pancreatitis-Associated Intestinal Inflammation via Nrf2 Signaling

Severe acute pancreatitis (SAP) is a challenging disease with high morbidity and mortality, often complicated by multiple organ dysfunction syndrome (MODS). The intestine, a major organ involved in MODS, correlates strongly with the evolution of the disease. In this study, we demonstrated that the DPP4 inhibitor, sitagliptin, protects SAP-associated intestinal injury both in vitro and in vivo. These beneficial effects were achieved by suppressing oxidative stress and inflammatory responses. Moreover, in sitagliptin-treated SAP mice, expression of Nrf2 was induced and that of NF-κB was reduced, compared to the control SAP mice. In addition, we used Nrf2^−/− mice to test the protective effect of Nrf2 during sitagliptin treatment of SAP; our results indicated that Nrf2^−/− mice had greater pancreatic and intestinal injury than wild-type mice. Taken together, high levels of ROS induced by SAP may be inhibited by sitagliptin, possibly by inactivating the Nrf2-NF-κB pathway.

Apoptosis perturbations and expression of regulatory inflammatory factors in cisplatin-depleted rat livers under l-arginine protection

Hepatic injury is one of the most common complications associated with cisplatin (CIS) use. Recently, liver protection lines are being discovered to stop the hepatic cell death due to inflammatory and apoptotic perturbations. l-arginine has protective effects in several models of liver injury. This study was designed to investigate the possible protective effect of l-arginine against CIS-induced acute hepatic injury in rats. Rats were divided into 4 groups: control, l-arginine, CIS, l-arginine + CIS. Liver function, oxidative stress, inflammatory cytokines, and apoptosis markers were assessed. l-arginine pretreatment protected the liver against CIS-induced toxicity as indicated by significantly alleviating the changes in liver function along with restoration of the antioxidant status. This finding was confirmed with the markedly improved pathological changes. l-arginine showed anti-inflammatory effect through the reduction of liver expression of iNOS, TNF-α, and NF-κβ, which were ameliorated to significant levels. Furthermore, l-arginine administration downregulated the liver expression of the apoptotic marker, caspase-3. The results recommend l-arginine as a hepatoprotective agent against CIS toxicity. Mostly, this hepatoprotective effect of l-arginine involved anti-inflammatory and anti-apoptotic activities.

Hyaluronic acid mediated biomineralization of multifunctional ceria nanocomposites as ROS scavengers and tumor photodynamic therapy agents

A novel HA@ceria nanoquantum dots (HA@CQDs) exhibit efficient protective effects against damage induced by ROS. More importantly, aided by H₂O₂, the HA@CQDs-Ce6/H₂O₂ significantly enhanced PDT efficacy for the tumor therapy.

Synthesis, characterization, and pharmacological evaluation of zinc oxide nanoparticles formulation

Zinc oxide nanoparticles (ZnONPs) are being used extensively in manufacturing skin lotions and food products and in various biological and pharmaceutical industries because of their immunomodulatory and antimicrobial properties. In this study, ZnONPs were synthesized by a precipitation method and characterized by X-ray diffraction (XRD) techniques, scanning electron microscopy (SEM), and ultraviolet-visible spectroscopy to investigate their structural, morphological, and optical properties. For in vivo evaluation, 40 healthy albino mice were randomly allocated to four equal groups among which the first one was the control group, while the second, third, and fourth were treated with carbon tetrachloride (CCl₄), a blend of CCl₄ and ZnONPs, and ZnONPs alone, respectively, for 21 days. The XRD analysis confirmed hexagonal wurtzite type structures having an average crystallite size of 41.54 nm. The morphology of ZnONPs analyzed through SEM showed uniform distribution of the grains and shape of the synthesized oxide. The energy band gap of the ZnONPs was found to be 3.498 eV. Hepatic and renal damage following CCl₄ administration was apparent after 14 days and was increased at the 21st day, showing nodular fibrotic masses in the liver and bumpy surfaces in the kidney as observed by gross and histological examination. Coadministration of ZnONPs (15 mg/kg b.w. intragastrically 5 days a week) significantly prevented the CCl₄-dependent increases in alanine transaminase, aspartate transaminase, creatinine, and urea levels, suggesting a protective potential of ZnONPs.

New application of the commercial sweetener rebaudioside a as a hepatoprotective candidate: Induction of the Nrf2 signaling pathway

A large population of drug candidates have failed "from bench to bed" due to unwanted toxicities. We intend to develop an alternative approach for drug discovery, that is, to seek candidates from "safe" compounds. Rebaudioside A (Reb-A) is an approved commercial sweetener from Stevia rebaudiana Bertoni. We found that Reb-A protects against carbon tetrachloride (CCl₄)-induced oxidative injury in human liver hepatocellular carcinoma (HepG2) cells. Reb-A showed antioxidant activity on reducing cellular reactive oxygen species and malondialdehyde levels while increasing glutathione levels and superoxide dismutase and catalase activities. Reb-A treatment induced nuclear factor erythroid-derived 2-like 2 (Nrf2) activation and antioxidant response element activity, as well as the expression of heme oxygenase-1 (HO-1) and NAD(P)H quinone oxidoreductase 1 (NQO1). Further mechanistic studies indicated that c-Jun N-terminal kinase (JNK), extracellular signal-regulated protein kinase (ERK), mitogen-active protein kinase (MAPK) and protein kinase C epsilon (PKCε) signaling was upregulated. Thus, the present in vitro study conclusively demonstrated that Reb-A is an activator of Nrf2 and is a potential candidate hepatoprotective agent. More importantly, the present study illustrated that seeking drug candidates from "safe" compounds is a promising strategy.

Characterization of Triptolide-Induced Hepatotoxicity by Imaging and Transcriptomics in a Novel Zebrafish Model

Triptolide is a vine extract used in traditional Chinese medicines and associated with hepatotoxicity. In vitro data suggest that inhibition of RNA synthesis may be the mechanism of toxicity. For studying drug-induced liver injury the zebrafish has experimental, practical and financial advantages compared with rodents. The aim of this study was to explore the mechanism of triptolide toxicity using zebrafish as the model system. The effect of triptolide exposure on zebrafish larvae was determined with regard to mortality, histology, expression of liver specific microRNA-122 and liver volume. Fluorescent microscopy was used to track toxicity in the Tg(-2.8lfabp:GFP)^as3 zebrafish line. Informed by microscopy, RNA-sequencing was used to explore the mechanism of toxicity. Triptolide exposure resulted in dose-dependent mortality, a reduction in the number of copies of microRNA-122 per larva, hepatocyte vacuolation, disarray and oncotic necrosis, and a reduction in liver volume. These findings were consistent across replicate experiments. Time-lapse imaging indicated the onset of injury was 6 h after the start of exposure, at which point, RNA-sequencing revealed that 88% of genes were down-regulated. Immune response associated genes were up-regulated in the triptolide-treated larvae including nitric oxide synthase. Inhibition of nitric oxide synthase increased mortality. Triptolide induces hepatotoxicity in zebrafish larvae. This represents a new model of drug-induced liver injury that complements rodents. RNA sequencing, guided by time-lapse microscopy, revealed early down-regulation of genes consistent with previous invitro studies, and facilitated the discovery of mechanistic inflammatory pathways.

Tanshinol ameliorates CCl4-induced liver fibrosis in rats through the regulation of Nrf2/HO-1 and NF-κB/IκBα signaling pathway

Tanshinol, a water-soluble component isolated from Salvia miltiorrhiza Bunge, has a variety of biological activities involving anti-fibrotic effect. However, the exact role and the underlying mechanisms remain largely unclear. This study mainly focused on the anti-hepatic fibrotic activities and mechanisms of tanshinol on carbon tetrachloride (CCl4)-induced liver fibrosis in rats via anti-oxidative and anti-inflammation pathways. The rats were divided into 4 groups as follows: control, model, tanshinol 20 mg/kg, and tanshinol 40 mg/kg. Except for the control group, CCl4 was used to induce liver fibrosis processing for 8 weeks, meanwhile rats in tanshinol groups were intraperitoneally injected with additional tanshinol. Control group simultaneously received the same volumes of olive oil and saline. The potentially protective effect and mechanisms of tanshinol on liver fibrosis in rats were evaluated. The serum levels of alanine aminotransferase, aspartate aminotransferase, and total bilirubin were obviously lower in the tanshinol treatment groups related to model group. Compared with the model group, the levels of hyaluronic acid, type IV collagen, Laminin (LN), and procollagen III peptide (PIIIP) in serum were significantly decreased after tanshinol treatment. Furthermore, tanshinol could regulate Nrf2/HO-1 signaling pathway and increase the level of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and also decrease the level of malondialdehyde (MDA) to against damage induced by oxidative stress. Simultaneously tanshinol could regulate nuclear factor kappa B signaling pathway to inhibit expression of inflammation factors, including transforming growth factor-β, tumor necrosis factor-α, Cox-2, interleukin-1β, and interleukin-6. In summary, our research demonstrated that tanshinol has protective effect on CCl4-induced liver fibrosis via inhibiting oxidative stress and inflammation, which may be associated with the regulation of nuclear factor erythroid2-related factor 2/hemeoxygenase-a and nuclear factor kappa B/inhibitor of kappa B alpha signaling pathways.

Hepaprotective Effect of Standardized Ecklonia stolonifera Formulation on CCl4-Induced Liver Injury in Sprague-Dawley Rats

The liver is an essential organ for the detoxification of exogenous xenobiotics, drugs and toxic substances. The incidence rate of non-alcoholic liver injury increases due to dietary habit change and drug use increase. Our previous study demonstrated that Ecklonia stolonifera (ES) formulation has hepatoprotective effect against alcohol-induced liver injury in rat and tacrine-induced hepatotoxicity in HepG2 cells. This present study was designated to elucidate hepatoprotective effects of ES formulation against carbon tetrachloride (CCl₄)-induced liver injury in Sprague Dawley rat. Sixty rats were randomly divided into six groups. The rats were treated orally with ES formulation and silymarin (served as positive control, only 100 mg/kg/day) at a dose of 50, 100, or 200 mg/kg/day for 21 days. Seven days after treatment, liver injury was induced by intraperitoneal injection of CCl₄ (1.5 ml/kg, twice a week for 14 days). The administration of CCl₄ exhibited significant elevation of hepatic enzymes (like AST and ALT), and decrease of antioxidant related enzymes (superoxide dismutase, glutathione peroxidase and catalase) and glutathione. Then, it leaded to DNA damages (8-oxo-2′-deoxyguanosine) and lipid peroxidation (malondialdehyde). Administration of ES formulation inhibited imbalance of above factors compared to CCl₄ induced rat in a dose dependent manner. Real time PCR analysis indicates that CYP2E1 was upregulated in CCl₄ induced rat. However, increased gene expression was compromised by ES formulation treatment. These findings suggests that ES formulation could protect hepatotoxicity caused by CCl₄ via two pathways: elevation of antioxidant enzymes and normalization of CYP2E1 enzyme.

Proanthocyanidin protects against cisplatin-induced oxidative liver damage through inhibition of inflammation and NF-κβ/TLR-4 pathway

Although cisplatin (CIS) is a highly effective anticancer drug, hepatotoxicity is one of the most common adverse effects associated with its use. Recently, reactive oxygen species (ROS) and inflammation are suggested to be key factors in the pathophysiology of CIS-induced acute liver damage. The aim of this study is to investigate the possible protective effect of proanthocyanidin (PRO) against CIS-induced acute hepatotoxicity. Rats were divided into four groups: 1, Control; 2, PRO; 3, CIS; and 4, PRO + CIS. Biochemical studies and histopathology were used to assess liver damage. ROS, inflammatory cytokines, nuclear factor kappa beta (NF-κβ), inducible cyclooxygenase enzyme (COX-2), inducible nitric oxide synthase (iNOS), toll-like receptor-4 (TLR-4) gene expression, and apoptotic markers were also assessed. PRO pretreatment protected the liver against CIS-induced toxicity as indicated by decreased plasma levels of liver function enzymes and the normal liver histopathology observed in the PRO + CIS group. PRO pretreatment also diminished indicators of oxidative stress in the liver, including nitric oxide (NO) and malondialdehyde (MDA). It also increased the antioxidants, reduced glutathione (GSH), glutathione peroxidase (GPx), superoxide dismutase (SOD), and catalase (CAT) in the liver. Plasma interleukin-1 beta (IL-1β), IL-6, and tumor necrosis factor-alpha (TNF-α) were all reduced. Liver gene expression of NF-κβ, COX-2, iNOS, and TLR-4 were all downregulated. Furthermore, PRO administration downregulated the liver expression of the apoptotic marker, Bax, while upregulated the antiapoptotic marker, Bcl2. In conclusion, our results revealed that PRO may protect against CIS-induced acute liver damage mainly through inhibition of ROS, inflammation, and apoptosis.

The protective effect of hyperoside on carbon tetrachloride-induced chronic liver fibrosis in mice via upregulation of Nrf2

CONTEXT

Hyperoside was used to treat cardiovascular disease for many years in China. It was shown great effect on regulation of lipid metabolism. But there is lack of reports about the effects of hyperoside on liver diseases.

OBJECTIVE

This study was designed to investigate the potentially protective effects of hyperoside and the role of transcription factor nuclear factor-erythroid 2(NF-E2)-related factor 2 (Nrf2) signaling in the regulation on Carbon Tetrachloride (CCl₄)-induced chronic liver fibrosis in mice.

MATERIALS AND METHODS

All mice were divided into six groups containing 6 animals per group. Mice in different group were given relative processing for 4 weeks. The potentially protective effects of hyperoside on CCl₄-induced chronic liver fibrosis in mice were depicted histologically and biochemically.

RESULTS

CCl₄ administration caused a marked increase in the levels of serum aminotransferases, serum monoamine oxidase (MAO) and lipid peroxidation, MAO in mouse liver homogenates. Also decreased activities of cellular antioxidant defense enzymes were found after CCl₄ exposure. Histopathological changes induced by CCl₄ including regenerative nodules, deteriorated parenchyma. Hyperoside and silymarin reduced these changes and attenuated the pathological effects of CCl₄ induced liver injury. In addition, hyperoside exhibited antioxidant effects in vitro. In Western blot analysis, the protein level of Nrf2 was downregulated after CCl₄ administration and reversed by hyperoside.

CONCLUSION

Hyperoside increased the activity of the antioxidant and phase II detoxifying enzymes through the activation of Nrf2 nuclear translocated in the CCl₄-induced liver fibrosis mice.

Hepatoprotective effect of sitagliptin against methotrexate induced liver toxicity

Sitagliptin is selective dipeptidyl peptidase-4 inhibitor (DPP4-I), used clinically as a new oral anti-diabetic agent. This study explored the underlying mechanisms of the hepatoprotective role of sitagliptin pretreatment against methotrexate (MTX) induced hepatotoxicity in mice. Forty mice were divided into four groups (10 mice each); control, MTX, and two sitagliptin groups (pretreated with sitagliptin 10 and 20 mg/kg/day, respectively) for five consecutive days prior to MTX injection. Results showed that MTX induced marked hepatic injury in the form of cloudy swelling, hydropic degeneration, apoptosis and focal necrosis in all hepatic zones. Biochemical analysis revealed significant increase in the serum transaminases, alkaline phosphatase and lactate dehydrogenase in MTX group. Oxidative stress and depressed antioxidant system of the hepatic tissues were evident in MTX group. MTX down-regulated nuclear factor erythroid 2-related factor 2 (Nrf2) expression and reduced its binding capacity. Additionally, MTX increased the activation and the expression of nuclear factor kappa-B (NF-κB) and downstream inflammatory mediators. MTX induced the activation of inducible nitric oxide synthase (iNOS) and increased nitrite/nitrate level. Finally, hepatic cellular apoptosis was clearly obvious in MTX-intoxicated animals using TUNEL staining. Also, there was increase in the immunoexpression of pro-apoptotic protein Bax, increase in Bax and caspase-3 levels and decrease in the level of anti-apoptotic Bcl2 in liver. On the other hand, sitagliptin pretreatment significantly ameliorated all of the above mentioned biochemical, histopathological, immunohistochemical changes induced by MTX. These results provide new evidences that the hepatoprotective effect of sitagliptin is possibly mediated through modulation of Nrf2 and NF-κB signaling pathways with subsequent suppression of inflammatory and apoptotic processes.

Contribution of inducible and neuronal nitric oxide synthases to mitochondrial damage and melatonin rescue in LPS-treated mice

NOS isoform activation is related to liver failure during sepsis, but the mechanisms driving mitochondrial impairment remain unclear. We induced sepsis by LPS administration to inducible nitric oxide synthase (iNOS^-/-) and neuronal nitric oxide synthase (nNOS^-/-) mice and their respective wild-type controls to examine the contribution of iNOS to mitochondrial failure in the absence of nNOS. To achieve this goal, the determination of messenger RNA (mRNA) expression and protein content of iNOS in cytosol and mitochondria, the mitochondrial respiratory complex content, and the levels of nitrosative and oxidative stress (by measuring 3-nitrotyrosine residues and carbonyl groups, respectively) were examined in the liver of control and septic mice. We detected strongly elevated iNOS mRNA expression and protein levels in liver cytosol and mitochondria of septic mice, which were related to enhanced oxidative and nitrosative stress, and with fewer changes in respiratory complexes. The absence of the iNOS, but not nNOS, gene absolutely prevented mitochondrial impairment during sepsis. Moreover, the nNOS gene did not modify the expression and the effects of iNOS here shown. Melatonin administration counteracted iNOS activation and mitochondrial damage and enhanced the expression of the respiratory complexes above the control values. These effects were unrelated to the presence or absence of nNOS. iNOS is a main target to prevent liver mitochondrial impairment during sepsis, and melatonin represents an efficient antagonist of these iNOS-dependent effects whereas it may boost mitochondrial respiration to enhance liver survival.

Hepatoprotective potential of glyceryl trinitrate against chemically induced oxidative stress and hepatic injury in rats

Glyceryl trinitrate (GTN) has been used widely as a potent vasodilator to treat heart conditions, such as angina pectoris and chronic heart failure. This study aims to elucidate the effect of exogenous nitric oxide (NO) administration, using GTN, on carbon tetrachloride (CCl4)-induced oxidative stress and liver injury in rats. The results obtained demonstrated that NO generated by the administration of GTN affords protection against CCl4-induced oxidative stress and liver injury. Administration of CCl4 resulted in a significant ( p < 0.001) increase in lipid peroxidation and tissue damage markers (aspartate and alanine transaminase and lactate dehydrogenase) release in serum. Parallel to these changes, CCl4 also caused downregulation of antioxidant enzymes including glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione-S-transferase (GST), and several fold induction in γ-glutamyl transpeptidase (GGT) activity. Subsequent administration of GTN resulted in significant ( p < 0.001) recovery of GSH-metabolizing enzymes in a dose-dependent manner. Further, administration of NO inhibitor, NG-nitro-l-arginine methyl ester (l-NAME), exacerbated CCl4-induced oxidative tissue injury. Overall, the study suggests that GTN might suppress oxidant-induced tissue injury and hepatotoxicity in rats.

The protective effect of vildagliptin in chronic experimental cyclosporine A-induced hepatotoxicity

The study examined the effect of dipeptidyl peptidase-4 (DPP-4) inhibitor, vildagliptin, in cyclosporine (CsA)-induced hepatotoxicity. Rats were divided into 4 groups treated for 28 days: control (vehicle), vildagliptin (10 mg/kg, orally), CsA (20 mg/kg, s.c.), and CsA-vildagliptin group. Liver function was assessed by measuring serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma glutamyltransferase (γGT), lactate dehydrogenase (LDH), and albumin, and histopathological changes of liver were examined. Oxidative stress markers were evaluated. Assessment of nuclear factor-kappa B (NF-κB) activity in hepatic nuclear extract, serum DPP-4, and expression of Bax and Bcl2 were also done. CsA-induced hepatotoxicity was evidenced by increase in serum levels of AST, ALT, and γGT; a decrease in serum albumin; and a significant alteration in hepatic architecture. Also, significant increase in thiobarbituric acid reactive substance (TBARS) and decrease in superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione (GSH) levels, increased expression Bax proteins with deceased expression of Bcl2, and increased hepatic activity of NF-κB and serum DPP-4 level were observed upon CsA treatment. Vildagliptin significantly improved all altered parameters induced by CsA administration. Vildagliptin has the potential to protect the liver against CsA-induced hepatotoxicity by reducing oxidative stress, DPP-4 activity, apoptosis, and inflammation.

Angiotensin-converting enzyme inhibitor prevents oxidative stress, inflammation, and fibrosis in carbon tetrachloride-treated rat liver

Hepatic fibrosis is a common feature of chronic liver injury, and the involvement of angiotensin II in such process has been studied earlier. We hypothesized that anti-angiotensin II agents may be effective in preventing hepatic fibrosis. In this study, Long Evans female rats were used and divided into four groups such as Group-I, Control; Group-II, Control + ramipril; Group-III, CCl4; and Group-IV, CCl4 + ramipril. Group II and IV are treated with ramipril for 14 d. At the end of treatment, the livers were removed, and the level of hepatic marker enzymes (aspartate aminotransferase, Alanine aminotransferase, and alkaline phosphatase), nitric oxide, advanced protein oxidation product , catalase activity, and lipid peroxidation were determined. The degree of fibrosis was evaluated through histopathological staining with Sirius red and trichrome milligan staining. Carbon-tetrachloride (CCl4) administration in rats developed hepatic dysfunction and raised the hepatic marker enzymes activities significantly. CCl4 administration in rats also produced oxidative stress, inflammation, and fibrosis in liver. Furthermore, angiotensinogen-inhibitor ramipril normalized the hepatic enzymes activities and improved the antioxidant enzyme catalase activity. Moreover, ramipril treatment ameliorated lipid peroxidation and hepatic inflammation in CCl4-treated rats. Ramipril treatment also significantly reduced hepatic fibrosis in CCl4-administered rats. In conclusion, our investigation suggests that the antifibrotic effect of ramipril may be attributed to inhibition of angiotensin-II mediated oxidative stress and inflammation in liver CCl4-administered rats.

Ameliorative effect of trimetazidine on cisplatin-induced hepatotoxicity in rats

This study was designed to evaluate the protective effects of trimetazidine (TMZ) against cisplatin (CP) induced liver damage in rats. Animals were distributed among 4 groups as follows: control group; TMZ group (20 mg/kg body mass, per oral), which was treated for 10 days; CP group (6 mg/kg, by intraperitoneal injection), which received a single injection; and the CP + TMZ group (20 mg/kg, per oral), which received TMZ 4 days before and 6 days after CP injection. The extent of hepatic damage was studied by assessing biochemical parameters and histopathological evaluation of the extracted liver tissue. The results revealed that liver enzymes were markedly elevated after injection of CP, as evident from significant increases in the serum levels of alanine transaminase (AST), alanine aminotransferase (ALT), gamma glutamyl transferase (γ-GT), and lactate dehydrogenase (LDH), as well as marked changes to the liver architecture, with a significant decrease in serum levels of albumin. There were also marked changes to the antioxidant defense system, as indicated by significant decreases in total antioxidants and hepatic levels of reduced glutathione (GSH) and superoxide dismutase (SOD), together with a significant increase in lipid peroxidation. However, there was a significant increase in the activity of hepatic nuclear factor kappa B (NF-κB) as well as hepatic Bax protein expression. We conclude that TMZ protects against CP-induced liver damage through scavenging free radicals and anti-inflammatory and antiapoptotic effects, as well as through reducing NF-κB activation.

Oligonol Ameliorates CCl₄-Induced Liver Injury in Rats via the NF-Kappa B and MAPK Signaling Pathways

Oxidative stress is thought to be a key risk factor in the development of hepatic diseases. Blocking or retarding the reactions of oxidation and the inflammatory process by antioxidants could be a promising therapeutic intervention for prevention or treatment of liver injuries. Oligonol is a low molecular weight polyphenol containing catechin-type monomers and oligomers derived from lychee fruit. In this study, we investigated the anti-inflammatory effect of oligonol on carbon tetrachloride- (CCl4-) induced acute hepatic injury in rats. Oral administration of oligonol (10 or 50 mg/kg) reduced CCl4-induced abnormalities in liver histology and serum AST and serum ALT levels. Oligonol treatment attenuated the CCl4-induced production of inflammatory mediators, including TNF-α, IL-1β, cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS) mRNA levels. Western blot analysis showed that oligonol suppressed proinflammatory nuclear factor-kappa B (NF-κB) p65 activation, phosphorylation of extracellular signal-regulated kinase (ERK), c-Jun NH2-terminal kinase (JNK), and p38 mitogen-activated protein kinases (MAPKs) as well as Akt. Oligonol exhibited strong antioxidative activity in vitro and in vivo, and hepatoprotective activity against t-butyl hydroperoxide-induced HepG2 cells. Taken together, oligonol showed antioxidative and anti-inflammatory effects in CCl4-intoxicated rats by inhibiting oxidative stress and NF-κB activation via blockade of the activation of upstream kinases including MAPKs and Akt.

Effects of pentoxifylline and alpha lipoic acid on methotrexate-induced damage in liver and kidney of rats

The aim of the current study was to investigate the probable protective effects of Pentoxifylline (PTX) and Alpha Lipoic Acid (ALA), which display anti-oxidative efficacy against hepatotoxicity and nephrotoxicity, those being the major side effects of Methotrexate (MTX). Rats were divided into four groups: a control group; MTX (20mg/kg/day) group; MTX+PTX (20mg/kg/day+50mg/kg/day) group; and an MTX+ALA (20mg/kg/day+100mg/kg/day) group. At the end of the experiment, biochemical, histochemical and immunohistochemical analyses were performed on liver and kidney tissues of rats. We determined Glutathione Peroxidase (GSH-Px), Superoxide Dismutase (SOD), Catalase (CAT), Malondialdehyde (MDA), Nitric Oxide (NO) and Xanthine Oxidase (XO) levels in the liver and kidney. Moreover, Gamma Glutamyl Transferase (GGT), Direct Bilirubin (DBil), Blood Urea Nitrogen (BUN), and urea levels were measured in the serum. The histochemical evaluation revealed a significant decrease in MTX caused damage in the PTX- and ALA-treated groups (especially in ALA group). On the other hand, the immune staining of iNOS and TNF-α were observed most densely in the MTX group, while the density decreased in the PTX- and ALA-administered groups. We determined increased GGT, BUN, urea and levels of CAT, MDA, NO, and XO values in both groups, while GSH-Px (an increase in liver tissue) and DBil levels were decreased in the group that received MTX. However, we determined decreased SOD levels in liver tissue. In the PTX and ALA groups, the levels of GGT, BUN and urea as well as the levels of CAT, MDA, NO and XO decreased (SOD increased in the liver tissue), and the levels of GSH-Px and DBil increased. In conclusion, it can be stated that, although ALA is more effective in preventing the toxic effects of MTX on the liver and kidney, PTX also has a preventive effect. As a result, we can readily suggest that ALA and PTX can have protective effects by decreasing MDA, NO, BUN and urea values as antioxidants against MTX-induced damage in liver and kidney of rats.

Supplementation of fresh ucche (Momordica charantia L. var. muricata Willd) prevented oxidative stress, fibrosis and hepatic damage in CCl4 treated rats

Background

Ucche (Momordica charantia L. var. muricata (Willd.) Chakravarty) has been reported to possess many benefits and medicinal properties. However, the protective effect of ucche against carbon tetrachloride (CCl₄) induced hepatotoxicity have not been clarified fully yet. The aim of the present study was to investigate the effects of ucche on oxidative stress and inflammation in liver of CCl₄ treated rats.

Methods

Female Long Evans rats were administered with CCl₄ orally (1 ml/kg) twice a week for 2 weeks and were supplemented with freshly prepared crashed ucche (10% wt/wt of diet) with powdered chaw food. Both plasma and liver tissues were analyzed for AST, ALT and ALP activities. Oxidative stress parameters were measure by determining malondialdehyde (MDA), nitric oxide (NO), advanced protein oxidation product (APOP), and reduced glutathione (GSH) concentrations and catalase activities in plasma and liver tissues. Moreover, inflammation and tissue fibrosis were confirmed by histological staining of liver tissue sections.

Results

Our data suggest that ucche significantly prevented CCl₄-induced hepatotoxicity, indicated by both diagnostic indicators of liver damage (serum transferases activities) and histopathological analysis. Moreover, CCl₄ administration induced profound elevation of reactive oxygen species (ROS) production and oxidative stress, as evidenced by increasing lipid peroxidation level and depletion of antioxidant enzymes in liver. Fresh ucche supplementation prevented the oxidative stresses and improved antioxidant enzyme function. Furthermore, fresh ucche supplementation reduced hepatic inflammatory cell infiltration, iron deposition and fibrosis in liver of CCl₄ treated rats.

Conclusion

In conclusion, these results suggested that the inhibition of CCl₄-induced inflammation by ucche is due at least in part to its anti-oxidant activity and its ability to modulate the inflammation and fibrosis in liver.

Thymoquinone attenuates cisplatin-induced hepatotoxicity via nuclear factor kappa-β

Background

Cisplatin (CP) is known as a potent anti-cancer drug. The most therapeutic adverse effect of CP is induced hepatotoxicity. In the present study, the protective effect of thymoquinone (TQ) on CP-induced hepatotoxicity was studied.

Methods

Wistar rats were divided into three groups (15 rats each). Group 1 served as the control group. Group 2 rats were injected ip with a single dose of CP (12 mg/kg b.w, i.p.). Group 3 rats were orally pre-treated with TQ (500 mg. kg⁻¹. day⁻¹) for one month, then the animals were injected i.p with CP 12 mg.kg⁻¹.

Results

The beneficial effects of TQ with its antioxidant/anti-inflammatory effects were observed. Injection of rats with CP markedly affected the liver functions and histopathological changes. The antioxidant enzyme activities and reduced glutathione (GSH) contents were significantly decreased while the levels of malondialdehyde (MDA) significantly increased. The electromobility shift assay (EMSA) showed a significant activation of NF-κB-p65 in the rat liver injected with CP. Furthermore, the expression and concentrations of inflammatory tumor necrosis factor (TNF-α), nitric oxide synthetase (iNOS), and interleukin (IL-1β) were markedly elevated in the CP injected rats. The administration of TQ improved all the altered functions, histopathology of the liver and attenuated the activated NF-κB. The antioxidant enzyme activities (glutathione peroxidase and glutathione –S transferase) of the rat livers were markedly increased while MDA was reduced as a result of TQ administration. In addition, the expression of TNF-α, iNOS, and IL-1β were markedly reduced.

Conclusion

It was concluded that, TQ has potential benefits in the prevention of the onset and progression of CP induced hepatotoxicity.

Nrf2 pathway activation contributes to anti-fibrosis effects of ginsenoside Rg1 in a rat model of alcohol- and CCl4-induced hepatic fibrosis

AIM

To investigate the anti-fibrosis effects of ginsenoside Rg1 on alcohol- and CCl4-induced hepatic fibrosis in rats and to explore the mechanisms of the effects.

METHODS

Rats were given 6% alcohol in water and injected with CCl4 (2 mL/kg, sc) twice a week for 8 weeks. Rg1 (10, 20 and 40 mg/kg per day, po) was administered in the last 2 weeks. Hepatic fibrosis was determined by measuring serum biochemical parameters, HE staining, Masson's trichromic staining, and hydroxyproline and α-SMA immunohistochemical staining of liver tissues. The activities of antioxidant enzymes, lipid peroxidation, and Nrf2 signaling pathway-related proteins (Nrf2, Ho-1 and Nqo1) in liver tissues were analyzed. Cultured hepatic stellate cells (HSCs) of rats were prepared for in vitro studies.

RESULTS

In the alcohol- and CCl4-treated rats, Rg1 administration dose-dependently suppressed the marked increases of serum ALT, AST, LDH and ALP levels, inhibited liver inflammation and HSC activation and reduced liver fibrosis scores. Rg1 significantly increased the activities of antioxidant enzymes (SOD, GSH-Px and CAT) and reduced MDA levels in liver tissues. Furthermore, Rg1 significantly increased the expression and nuclear translocation of Nrf2 that regulated the expression of many antioxidant enzymes. Treatment of the cultured HSCs with Rg1 (1 μmol/L) induced Nrf2 translocation, and suppressed CCl4-induced cell proliferation, reversed CCl4- induced changes in MDA, GPX, PCIII and HA contents in the supernatant fluid and α-SMA expression in the cells. Knockdown of Nrf2 gene diminished these actions of Rg1 in CCl4-treated HSCs in vitro.

CONCLUSION

Rg1 exerts protective effects in a rat model of alcohol- and CCl4-induced hepatic fibrosis via promoting the nuclear translocation of Nrf2 and expression of antioxidant enzymes.

Resveratrol mitigate structural changes and hepatic stellate cell activation in N'-nitrosodimethylamine-induced liver fibrosis via restraining oxidative damage

Resveratrol, a polyphenol, found in skin of red grapes, peanuts and berries possesses anti-inflammatory, anti-carcinogenic and lipid modulation properties. Here, we demonstrate in vivo antifibrotic activity of resveratrol in a mammalian model, wherein hepatic fibrosis was induced by N'-nitrosodimethylamine (NDMA) administration. Apart from being a potent hepatotoxin, NDMA is a known mutagen and carcinogen, as well. To induce hepatic fibrosis, rats were administered NDMA (i.p.) in 10mg/kgb.wt thrice/week for 21 days. Another group of animals received resveratrol supplement (10mg/kgb.wt) subsequent to NDMA administration and were sacrificed weekly. The changes in selected biomarkers were monitored to compare profibrotic effects of NDMA and antifibrotic activity of resveratrol. The selected biomarkers were: sera transaminases, ALP, bilirubin, liver glycogen, LPO, SOD, protein carbonyl content, ATPases (Ca(2+), Mg(2+), Na(+)/K(+)) and hydroxyproline/collagen content. Alterations in liver architecture were assessed by H&E, Masson's trichrome and reticulin staining of liver biopsies. Immuno-histochemistry and immunoblotting were employed to examine expression of α-SMA. Our results demonstrate that during NDMA-induced liver fibrosis transaminases, ALP, bilirubin, hydroxyproline and liver collagen increases, while liver glycogen is depleted. The decline in SOD (>65%) and ATPases, which were concomitant with the elevation in MDA and protein carbonyls, strongly indicate oxidative damage. Fibrotic transformation of liver in NDMA-treated rats was verified by histopathology, immuno-histochemistry and immunoblotting data, with the higher expressivity of α-SMA-positive HSCs being most established diagnostic immuno-histochemical marker of HSCs. Resveratrol-supplement refurbished liver architecture by significantly restoring levels of biomarkers of oxidative damage (MDA, SOD, protein carbonyls and membrane-bound ATPases). Therefore, we conclude that antifibrotic effect of resveratrol is due to restrained oxidative damage and down-regulation of α-SMA, which inhibits HSC activation to obstruct liver fibrosis.

Hepatoprotective effects of Lycium chinense Miller fruit and its constituent betaine in CCl4-induced hepatic damage in rats

The hepatoprotective activities of Lycium chinense Miller (LC) fruit extract and its component betaine were investigated under carbon tetrachloride (CCl4)-induced hepatotoxicity in rats. The treatment of LC fruit extract significantly suppressed the increase of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the sera of CCl4 injured rats, and restored the decreased levels of anti-oxidant enzymes such as total antioxidant capacity (TAC), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) and suppressed the expression of inflammatory mediators including inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-1 and -2. To visualize the potential activity of betaine, a component of LC fruit, betaine was substituted for LC extract in CCl4 injured rats. The biochemical profile in CCl4 injured rats co-treated with betaine matched those of LC fruit treated CCl4 injured rats. The ameliorative effects of LC extract, as well as betaine, were also confirmed by histopathological examination. Collectively, the present findings imply that LC fruit, via its component betaine, mitigate CCl4-induced hepatic injury by increasing antioxidative activity and decreasing inflammatory mediators including iNOS and COX-1/COX-2.

The potential protective effect of Physalis peruviana L. against carbon tetrachloride-induced hepatotoxicity in rats is mediated by suppression of oxidative stress and downregulation of MMP-9 expression

The active constituent profile in Cape gooseberry (Physalis peruviana L.) juice was determined by GC-MS. Quercetin and kaempferol were active components in the juice. In this study we have evaluated its potential protective effect on hepatic injury and fibrosis induced by carbon tetrachloride (CCl4). Twenty-eight rats divided into 4 groups: Group I served as control group, and Group II received weekly i.p. injection of 2 mL CCl4/kg bwt for 12 weeks. Group III were supplemented with Physalis juice via the drinking water. The animals of Group IV received Physalis juice as Group III and also were intraperitoneally injected weekly with 2 mL CCl4/kg bwt for 12 weeks. Hepatoprotective effect was evaluated by improvement in liver enzymes serum levels, reduction in collagen areas, downregulation in expression of the fibrotic marker MMP-9, reduction in the peroxidative marker malonaldehyde and the inflammatory marker nitric oxide, and restoration of the activity of antioxidant enzymatic and nonenzymatic systems, namely, glutathione content, superoxide dismutase, catalase, glutathione-S-transferase, glutathione peroxidase, and glutathione reductase activities. The results show that the potential hepatoprotective effects of Physalis peruviana may be due to physalis acts by promotion of processes that restore hepatolobular architecture and through the inhibition of oxidative stress pathway.

Multimechanistic antifibrotic effect of biochanin a in rats: implications of proinflammatory and profibrogenic mediators

OBJECTIVE

Biochanin A (BCA) is an isoflavone found in red clover and peanuts. Recently, it drew much attention as a promising anticancer and antioxidant. Due to its diversity in pharmacological actions, we were encouraged to investigate its potential as an antifibrotic, elucidating the different molecular mechanisms involved.

DESIGN

Rats were pretreated with BCA, then injected with carbon tetrachloride (CCl4) for 6 weeks. Changes in liver weight and histology were examined and levels of aspartate and alanine aminotransferases, cholesterol, triglycerides, alkaline phosphatase and total bilirubin measured. To assess hepatic efficiency, indocyanine green was injected and its clearance calculated and albumin, total proteins and insulin-like growth factor-1 expression were measured. Cytochrome P4502E1 activity, cytochrome P4501A1 expression, in addition to sulfotransferase1A1 expression were determined to deduce the effect of BCA on hepatic metabolism. As oxidative stress markers, lipid peroxides levels, reduced glutathione, superoxide dismutase and catalase activities, as well as the total antioxidant capacity, were assessed. Nitric oxide, inducible nitric oxide synthase and cyclooxygenase-2 were used as indicators of the inflammatory response. Signaling pathways involving tumor necrosis factor-alpha, nuclear factor-kappa B, transforming growth factor-beta1, matrix metalloproteinase-9 and alpha-smooth muscle actin were investigated accordingly. Extent of fibrosis was examined by Masson's stain and measuring hydroxyproline levels.

RESULTS

BCA pretreatment significantly protected against the chronic damage of CCl4. Liver injury, oxidative stress, inflammation and fibrosis markers decreased, while hepatic efficiency improved.

CONCLUSION

Our findings suggested that BCA administration protects against fibrotic complications, a property that can be contributed to the multimechanistic approach of the drug.

Bees' honey attenuation of metanil-yellow-induced hepatotoxicity in rats

The present study aims to investigate the protective effect of bees' honey against metanil-yellow-induced hepatotoxicity in rats. Rats were divided into 7 groups: control group; three groups treated with 50, 100, and 200 mg/kg metanil yellow, and three groups treated with metanil yellow plus 2.5 mg · kg(-1) · day(-1) bees' honey for 8 weeks. The obtained data showed that the antioxidant/anti-inflammatory activity of bees' honey reduced the oxidative stress in the liver tissue and downregulated the inflammatory markers. In addition, the elevated levels of AGE and the activated NF- κ B in the metanil-yellow-treated animals were significantly attenuated. Moreover, the levels of TNF- α and IL-1 β were significantly attenuated as a result of bees' honey administration. Furthermore, the histopathological examination of the liver showed that bees' honey reduced fatty degeneration, cytoplasmic vacuolization, and necrosis in metanil-yellow-treated rats. In conclusion, the obtained data suggest that bees' honey has hepatoprotective effect on acute liver injuries induced by metanil-yellow in vivo, and the results suggested that the effect of bees' honey against metanil yellow-induced liver damage is related to its antioxidant/anti-inflammatory properties which attenuate the activation of NF- κ B and its controlled genes like TNF- α and IL-1 β .

Biochanin A protects against acute carbon tetrachloride-induced hepatotoxicity in rats

Biochanin A (BCA) is an isoflavone found in red clover possessing multiple pharmacological activities including antimicrobial, antioxidant, and anticancer ones. The present study aimed to assess its hepatoprotective potential at different doses in a carbon tetrachloride (CCl4)-induced hepatotoxicity model in rats. The effects on hepatic injury were explored by measuring serum levels of alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase. Furthermore, the serum levels of glucose, urea, creatinine, total bilirubin, total proteins, triglycerides, and total cholesterol were determined. The metabolic capacity of the liver was assessed by measuring changes in cytochrome P450 2E1 activity. The underlying mechanisms were substantiated by measuring oxidative stress markers as catalase, superoxide dismutase, glutathione peroxidase, glutathione transferase, glutathione reductase, reduced glutathione, total antioxidant capacity, and lipid peroxidation, as well as inflammation markers such as nitric oxide, inducible nitric oxide synthase, cyclooxygenase2, tumor necrosis factor-α, and leukocyte-common antigen. The results were confirmed by histopathological examination, and the median lethal dose was determined to confirm the safety of the drug. BCA successively protected against CCl4-induced damage, normalizing many parameters to that of the control group. The study indicates that BCA possesses multimechanistic hepatoprotective activity that can be attributed to its antioxidant, anti-inflammatory, and immunomodulatory actions.

Hepatoprotection by chemical constituents of the marine brown alga Spatoglossum variabile: a relation to free radical scavenging potential

CONTEXT

In the course of searching hepatoprotective agents from natural sources, the protective effect of chemical constituents of the marine brown alga Spatoglossum variabile Figaro et DE Notar (Dictyoaceae) against CCl₄-induced liver damage in Wistar rats was investigated. The compounds were first investigated for in vitro radical scavenging potential and were also tested for β-glucuronidase inhibition to further explore the relationship between hepatoprotection and antiradical potential.

METHODS

The compounds cinnamic acid esters 1 and 2 and aurone derivatives 3 and 4 were first investigated for in vitro radical scavenging potential against 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH), and superoxide anion radicals. In vivo hepatoprotective studies were performed in seven groups (n = 6) of Wistar rats. The test groups were pretreated with compounds (10 mg/kg body weight, po) orally for 30 min before the intraperitoneal administration of a dose of 20% CCl₄ diluted with dietary cooking oil. Moreover, compounds were also tested for β-glucuronidase inhibition to explore the relationship between hepatoprotection and radical scavenging potential.

RESULTS

The test compounds 1-4 were found to exhibit antiradical activity against 1,1-diphenyl-2-picrylhydrazyl radicals with IC₅₀ values ranging between 54 and 138 µM, whereas aurone derivatives 3 and 4 additionally exhibited superoxide anion scavenging effects with IC₅₀ values of 95 and 87 µM, respectively. In addition, these compounds were found to be weak inhibitors of xanthine oxidase (IC₅₀ ≥1000 µM). In animal model, pretreatment with compounds 2-4 significantly blocked the CCl₄-induced increase in the levels of the serum biochemical markers.

CONCLUSION

It appears that the hepatoprotection afforded by these compounds was mainly due to their radical scavenging activity that protected the cells from the free radicals generated by CCl₄-induced hepatotoxicity.

The protective effect of glycyrrhetinic acid on carbon tetrachloride-induced chronic liver fibrosis in mice via upregulation of Nrf2

This study was designed to investigate the potentially protective effects of glycyrrhetinic acid (GA) and the role of transcription factor nuclear factor-erythroid 2(NF-E2)-related factor 2 (Nrf2) signaling in the regulation of Carbon Tetrachloride (CCl₄)-induced chronic liver fibrosis in mice. The potentially protective effects of GA on CCl₄-induced chronic liver fibrosis in mice were depicted histologically and biochemically. Firstly, histopathological changes including regenerative nodules, inflammatory cell infiltration and fibrosis were induced by CCl₄.Then, CCl₄ administration caused a marked increase in the levels of serum aminotransferases (GOT, GPT), serum monoamine oxidase (MAO) and lipid peroxidation (MDA) as well as MAO in the mice liver homogenates. Also, decreased nuclear Nrf2 expression, mRNA levels of its target genes such as superoxide dismutase 3 (SOD3), catalase (CAT), glutathione peroxidase 2 (GPX2), and activity of cellular antioxidant enzymes were found after CCl₄ exposure. All of these phenotypes were markedly reversed by the treatment of the mice with GA. In addition, GA exhibited the antioxidant effects in vitro by on FeCl₂-ascorbate induced lipid peroxidation in mouse liver homogenates, and on DPPH scavenging activity. Taken together, these results suggested that GA can protect the liver from oxidative stress in mice, presumably through activating the nuclear translocation of Nrf2, enhancing the expression of its target genes and increasing the activity of the antioxidant enzymes. Therefore, GA may be an effective hepatoprotective agent and viable candidate for treating liver fibrosis and other oxidative stress-related diseases.

Mechanism of the Inhibitory Effects of Eucommia ulmoides Oliv. Cortex Extracts (EUCE) in the CCl 4 -Induced Acute Liver Lipid Accumulation in Rats

Eucommia ulmoides Oliv. (EU) has been used for treatment of liver diseases. The protective effects of Eucommia Ulmoides Oliv. cortex extracts (EUCE) on the carbon tetrachloride- (CCl4-) induced hepatic lipid accumulation were examined in this study. Rats were orally treated with EUCE in different doses prior to an intraperitoneal injection of 1 mg/kg CCl4. Acute injection of CCl4 decreased plasma triglyceride but increased hepatic triglyceride and cholesterol as compared to control rats. On the other hand, the pretreatment with EUCE diminished these effects at a dose-dependent manner. CCl4 treatment decreased glutathione (GSH) and increased malondialdehyde (MDA) accompanied by activated P450 2E1. The pretreatment with EUCE significantly improved these deleterious effects of CCl4. CCl4 treatment increased P450 2E1 activation and ApoB accumulation. Pretreatment with EUCE reversed these effects. ER stress response was significantly increased by CCl4, which was inhibited by EUCE. One of the possible ER stress regulatory mechanisms, lysosomal activity, was examined. CCl4 reduced lysosomal enzymes that were reversed with the EUCE. The results indicate that oral pretreatment with EUCE may protect liver against CCl4-induced hepatic lipid accumulation. ER stress and its related ROS regulation are suggested as a possible mechanism in the antidyslipidemic effect of EUCE.

Therapeutic effect of coenzyme Q10 against experimentally-induced hepatocellular carcinoma in rats

The therapeutic potential of coenzyme Q10 was investigated in rats with hepatocellular carcinoma induced by trichloroacetic acid (0.5g/kg/day, p.o., for five days). Coenzyme Q10 treatment (0.4mg/kg/day, i.p.) was applied for four weeks following trichloroacetic acid administration. Coenzyme Q10 significantly suppressed lipid peroxidation, prevented the depletion of reduced glutathione and superoxide dismutase activity, and decreased the elevations of tumor necrosis factor-α and nitric oxide in liver tissue of rats with hepatocellular carcinoma. Also, the histopathological dysplastic changes induced by trichloroacetic acid in liver tissue were ameliorated by coenzyme Q10. Immunohistochemical analysis revealed that coenzyme Q10 significantly decreased the expression of hepPar-1, alpha-fetoprotein, inducible nitric oxide synthase, cyclooxygenase-2 and nuclear factor-κB in liver tissue of rats with hepatocellular carcinoma. It was concluded that coenzyme Q10 may represent a potential therapeutic option for liver carcinogenesis.

Hispidin analogue davallialactone attenuates carbon tetrachloride-induced hepatotoxicity in mice

In this study the protective effects of davallialactone (1), isolated from Inonotus xeranticus, have been examined against carbon tetrachloride (CCl₄-induced acute liver injury. Mice received subcutaneous injection of 1 (2.5, 5, and 10 mg/kg) for three days before CCl₄ injection (1 mg/kg). Protection from liver injury by 1 was confirmed by the observation of decreased serum transaminases and diminished necrosis of liver tissue. Reduced hepatic injury was very similar to that observed with silymarin, a known hepatoprotective drug used in this work for comparison. The groups treated with 1 had reduced reactive oxygen species (ROS), reduced serum malonyldialdehyde levels, and increased levels of liver Cu/Zn superoxide dismutase, as compared to the CCl₄ control group. The expression of heme oxygenase-1 in the liver tissue was increased and the activity of liver cytochrome P4502E1 was restored in the mice treated with 1. In addition, levels of serum tumor necrosis factor-alpha (TNF-α), inducible NO synthase (iNOS), and cyclooxygenase-2 (COX-2), numbers of macrophage, and cleaved caspase-3-positive hepatocytes were reduced in the groups treated with 1. These findings suggest that davallialactone has protective effects against CCl₄-induced acute liver injury, and this protection is likely due to the suppression of ROS-induced lipid peroxidation and inflammatory response.

Hepatoprotective effect of the ethanol extract of Vitis thunbergii on carbon tetrachloride-induced acute hepatotoxicity in rats through anti-oxidative activities

ETHNOPHARMACOLOGICAL RELEVANCE

Vitis thunbergii var. taiwaniana are traditionally used for the treatment of diarrhea, fracture and injury, jaundice, and hepatitis in Taiwan.

AIM OF THE STUDY

The hepatoprotective activity of its plant extracts seems to be been associated with its antioxidant activity. This paper aims to investigate the in vitro and in vivo antioxidant effects of the ethanol extract of Vitis thunbergii (EVT).

MATERIALS AND METHODS

In HPLC analysis, the fingerprint chromatogram of EVT was established. Antioxidant ability of EVT was investigated by employing several established in vitro methods. In vivo antioxidant activity was tested against CCl(4)-induced toxicity in mice. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were detected in the blood to indicate hepatic injury. Product of lipid peroxidation (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and reduced glutathione (GSH) contents were evaluated for oxidative stress in hepatic injury. Moreover, histopathological observation was assayed for the degree of hepatic injury.

RESULTS

EVT exhibited strong antioxidant ability in vitro. After oral administration of EVT significantly decreased ALT and AST, and ameliorated the oxidative stress in hepatic tissue and increased the activity of CAT, SOD, GPx, and GSH. Serum tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β), and nitric oxide (NO) were decreased in the group treated with CCl(4) plus EVT. Western blotting revealed that EVT blocked protein expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) in CCl(4)-treated rats, significantly. Histopathological examination of livers showed that EVT reduced fatty degeneration, cytoplasmic vacuolization and necrosis in CCl(4)-treated rats.

CONCLUSION

This study suggests that EVT possesses antioxidant effects in vitro and hepatoprotective effect on acute liver injuries induced by CCl(4)in vivo, and the results suggested that the effect of EVT against CCl(4)-induced liver damage is related to its antioxidant properties.

Improvement of oral bioavailability of glycyrrhizin by sodium deoxycholate/phospholipid-mixed nanomicelles

Glycyrrhizin (GL), extracted from the Glycyrrhiza glabra L., is active triterpenoid saponin components. However, due to its impermeability across the gastrointestinal mucosa, oral bioavailability of the drug was relatively low. To improve its oral bioavailability, formulation of GL as sodium deoxycholate/phospholipid-mixed nanomicelles (SDC/PL-MMs) has been performed in this study. GL-SDC/PL-MMs were produced by a film dispersion method and then investigated using photon correlation spectroscopy (PCS), zeta potential measurement, as well as its physical stability after storage for 10, 20, 30, 60, 90 and 120 days. To verify the theoretical hypothesis, pharmacokinetics and pharmacodynamic studies based on carbon tetrachloride (CCl(4))-induced acute liver injury was investigated. Results showed that a narrow size distributed nanomicelles with a mean particle size of 82.99 ± 7.5 nm and a zeta potential of -32.23 ± 1.05 mV was obtained. In the pharmacokinetics, GL-SDC/PL-MMs show a significant superiority in AUC(0-t), C(max) and other pharmacokinetic parameters compared with the control group. In the pharmacodynamic studies, compared with the bifendate control group, GL-SDC/PL-MMs showed an equivalent effect in reducing alanine aminotransferase (ALT), aspartate aminotransferase (AST) and improving the pathological changes of liver tissue. These results revealed that SDC/PL-MMs could enhance GL absorption in gastrointestinal tract and pharmacodynamic effect in the treatment of acute liver injury caused by CCl(4), and SDC/PL-MMs might be a good choice for oral delivery of poor bioavailability drug like GL.

Sesamol attenuates oxidative stress–mediated experimental acute pancreatitis in rats

Acute pancreatitis is a potentially fatal disease with no known cure. The initial events in acute pancreatitis may occur within the acinar cells. We examined the effect of sesamol on (i) a cerulein-induced pancreatic acinar cancer cell line, AR42J, and (ii) cerulein-induced experimental acute pancreatitis in rats. Sesamol inhibited amylase activity and increased cell survival. It also inhibited medium lipid peroxidation and 8-hydroxydeoxyguanosine in AR42J cells compared with the cerulein-alone groups. In addition, in cerulein-treated rats, sesamol inhibited serum amylase and lipase levels, pancreatic edema, and lipid peroxidation, but it increased pancreatic glutathione and nitric oxide levels. Thus, we hypothesize that sesamol attenuates cerulein-induced experimental acute pancreatitis by inhibiting the pancreatic acinar cell death associated with oxidative stress in rats.