Curcumin protects the rat liver from CCl4-caused injury and fibrogenesis by attenuating oxidative stress and suppressing inflammation

Maresin 1, a Proresolving Lipid Mediator, Mitigates Carbon Tetrachloride-Induced Liver Injury in Mice

Maresin 1 (MaR 1) was recently reported to have protective properties in several different animal models of acute inflammation by inhibiting inflammatory response. However, its function in acute liver injury is still unknown. To address this question, we induced liver injury in BALB/c mice with intraperitoneal injection of carbon tetrachloride with or without treatment of MaR 1. Our data showed that MaR 1 attenuated hepatic injury, oxidative stress, and lipid peroxidation induced by carbon tetrachloride, as evidenced by increased thiobarbituric acid reactive substances and reactive oxygen species levels were inhibited by treatment of MaR 1. Furthermore, MaR 1 increased activities of antioxidative mediators in carbon tetrachloride-treated mice liver. MaR 1 decreased indices of inflammatory mediators such as tumor necrosis factor-α, interleukin-6, interleukin-1β, monocyte chemotactic protein 1, myeloperoxidase, cyclooxygenase-2, and inducible nitric oxide synthase. Administration of MaR 1 inhibited activation of nuclear factor kappa B (NF-κb) and mitogen-activated protein kinases (MAPKs) in the liver of CCl4 treated mice. In conclusion, these results suggested the antioxidative, anti-inflammatory properties of MaR 1 in CCl4 induced liver injury. The possible mechanism is partly implicated in its abilities to inhibit ROS generation and activation of NF-κb and MAPK pathway.

Utility of Translocator Protein (18 kDa) as a Molecular Imaging Biomarker to Monitor the Progression of Liver Fibrosis

Hepatic fibrosis is the wound healing response to chronic hepatic injury caused by various factors. In this study, we aimed to evaluate the utility of translocator protein (18 kDa) (TSPO) as a molecular imaging biomarker for monitoring the progression of hepatic fibrosis to cirrhosis. Model rats were induced by carbon tetrachloride (CCl₄), and liver fibrosis was assessed. Positron emission tomography (PET) with N-benzyl-N-methyl-2-[7,8-dihydro-7-(2-[¹⁸F]fluoroethyl)-8-oxo-2-phenyl-9H-purin-9-yl]-acetamide ([¹⁸F]FEDAC), a radioprobe specific for TSPO, was used for noninvasive visualisation in vivo. PET scanning, immunohistochemical staining, ex vivo autoradiography, and quantitative reverse-transcription polymerase chain reaction were performed to elucidate the relationships among radioactivity uptake, TSPO levels, and cellular sources enriching TSPO expression in damaged livers. PET showed that uptake of radioactivity in livers increased significantly after 2, 4, 6, and 8 weeks of CCl₄ treatment. Immunohistochemistry demonstrated that TSPO was mainly expressed in macrophages and hepatic stellate cells (HSCs). TSPO-expressing macrophages and HSCs increased with the progression of liver fibrosis. Interestingly, the distribution of radioactivity from [¹⁸F]FEDAC was well correlated with TSPO expression, and TSPO mRNA levels increased with the severity of liver damage. TSPO was a useful molecular imaging biomarker and could be used to track the progression of hepatic fibrosis to cirrhosis with PET.

Curcumin, Silybin Phytosome(®) and α-R-Lipoic Acid Mitigate Chronic Hepatitis in Rat by Inhibiting Oxidative Stress and Inflammatory Cytokines Production

Chronic hepatitis is recognized as a worldwide health problem that gradually progresses towards cirrhosis and hepatocellular carcinoma. Despite the large number of experiments using animal models for allergic hepatitis, it is still difficult to produce a picture of chronic hepatitis. Therefore, this study was conducted to introduce an animal model approximating to the mechanism of chronicity in human hepatitis. The study also aimed to examine the hepatoprotective effects of curcumin, silybin phytosome(®) and α-R-lipoic acid against thioacetamide (TAA)-induced chronic hepatitis in rat model. TAA was administered intraperitoneally at a dose of 200 mg/kg three times weekly for 4 weeks. At the end of this period, a group of rats was killed to assess the development of chronic hepatitis in comparison with their respective control group. TAA administration was then discontinued, and the remaining animals were subsequently allocated into four groups. Group 1 was left untreated, whereas groups 2-4 were allowed to receive daily oral doses of curcumin, silybin phytosome(®) or α-R-lipoic acid, respectively, for 7 weeks. Increases in hepatic levels of malondialdehyde associated with TAA administration were inhibited in groups receiving supplements. Furthermore, glutathione depletion, collagen deposition, macrophage activation and nuclear factor κappa-B expression as well as tumour necrosis factor-α and interleukin-6 levels were significantly decreased in response to supplements administration. Serological analysis of liver function and liver histopathological examination reinforced the results. The above evidence collectively indicates that the antioxidant and anti-inflammatory activities of curcumin, silybin phytosome(®) and α-R-lipoic acid may confer therapeutic efficacy against chronic hepatitis.

Trinitrotoluene Induces Endoplasmic Reticulum Stress and Apoptosis in HePG2 Cells

Background

This study aims to describe trinitrotoluene (TNT)-induced endoplasmic reticulum stress (ERS) and apoptosis in HePG2 cells.

Material/Methods

HePG2 cells were cultured in vitro with 0, 6, 12, or 24 μg/ml TNT solution for 12, 24, and 48 h. Western blotting was performed to detect intracellular ERS-related proteins, including glucose-regulated protein (GRP) 78, GRP94, Caspase 4, p-Jun N-terminal kinase (JNK), and C/EBP homologous protein (CHOP). Real-time PCR was used to measure mRNA expression from the respective genes.

Results

The expressions of ERS-related proteins GRP78 and GRP94 as well as mRNA and protein expression of ERS signaling apoptotic CHOP in the TNT treatment group were significantly increased. In addition, the mRNA and protein expression levels of ERS-induced apoptotic protein Caspase-4 were significantly increased. Flow cytometry revealed that after TNT treatment, the apoptosis rate also significantly increased.

Conclusions

TNT could increase the expression levels of GRP78, GRP94, Caspase-4, and CHOP in HePG2 cells; this increase in protein expression might be involved in HePG2 apoptosis through the induction of the ERS pathway.

Curcumin inhibits cobalt chloride-induced epithelial-to-mesenchymal transition associated with interference with TGF-β/Smad signaling in hepatocytes

Epithelial-mesenchymal transition (EMT) occurs during adult tissue remodeling responses including carcinogenesis and fibrosis. Existing evidence reveals that hepatocytes can undergo EMT in adult liver, which is critically involved in chronic liver injury. We herein established a hypoxia-induced EMT model in human LO2 hepatocytes treated with cobalt chloride (CoCl2) in vitro, and evaluated the effects of curcumin, a natural antifibrotic compound, on hepatocyte EMT and explored the underlying molecular mechanisms. We found that CoCl2 at non-toxic doses induced a mesenchymal cell phenotype in hepatocytes and upregulated several mesenchymal markers including α-smooth muscle actin, vimentin, N-cadherin, fibronectin and Snail (an EMT-related transcription factor), but downregulated the epithelial marker E-cadherin in hepatocytes. However, curcumin reversed the morphological changes, abrogated the increased expression of mesenchymal markers, and rescued E-cadherin expression in CoCl2-treated hepatocytes, suggesting the inhibition of hepatocyte EMT in vitro. We further found that curcumin interfered with the transforming growth factor-β (TGF-β) signaling by reducing the expression of TGF-β receptor I and inhibiting the expression and phosphorylation of Smad2 and Smad3. Use of SB431542, a specific inhibitor of TGF-β receptor I, demonstrated that interference with the TGF-β/Smad pathway was associated with curcumin suppression of hepatocyte EMT. Our in vivo data showed that curcumin affected hepatic EMT in rat fibrotic liver caused by carbon tetrachloride, which was associated with the inhibition of TGF-β/Smad signaling. These findings characterized a novel mechanism by which curcumin modulated hepatocyte EMT implicated in treatment of liver fibrosis.

Molecular and Histopathological Study on the Ameliorative Effects of Curcumin Against Lead Acetate-Induced Hepatotoxicity and Nephrototoxicity in Wistar Rats

Lead (Pb(2+)) toxicity is the most common form of heavy metal intoxication in humans and animals. Therefore, the current study was conducted to evaluate the potential ameliorative effects of curcumin on lead acetate (LA)-induced deleterious effects in the liver and kidney. Forty male Wistar rats were divided into four equal groups; first group was used as a control and given both corn oil orally and vehicle of lead acetate intraperitoneally (i.p). Groups from 2-4 were treated with lead acetate (LA; 50 mg/kg BW i.p), curcumin (200 mg/kg BW orally), and curcumin plus lead acetate, respectively. Curcumin was administered 3 weeks before LA injection for 7 days. Pb(2+)-intoxicated rats have higher Pb(2+) levels compared to other treated groups. Results revealed that lead acetate significantly increased the serum levels of hepatic transaminases (GPT and GOT), urea and creatinine, while albumin was significantly decreased. In parallel, serum IgG, IgM, and IgA were significantly decreased in LA-injected rats. LA groups showed decrease in messenger RNA (mRNA) expression of catalase, SOD, GST, GPx, and alpha-1 acid glycoprotein (AGP), while the gene expression of desmin, vimentin, transforming growth factor-β1 (TGF-β1), monocyte chemoattractant protein-1 (MCP-1), and alpha-2 macroglobulin (α-2M) was increased. Prior and coadministration of curcumin with LA for 7 days significantly improved the ameliorated changes in liver and kidney, immunoglobulins, and mRNA expression. Moreover, curcumin ameliorated LA-induced congestion of hepatic and renal blood vessels and decreased fibrous tissue proliferation and necrosis of hepatocytes. In the kidney, LA-induced degeneration in tubular epithelium and intraluminal hyaline casts and prior curcumin administration restored normal renal structure with mild congestion of renal blood vessels. The results clarify the potential of curcumin to counteract the immunosuppressive alteration in gene expression as well as hepatic and renal damage occurred after Pb(2+) intoxication.

KLF2 exerts antifibrotic and vasoprotective effects in cirrhotic rat livers: behind the molecular mechanisms of statins

OBJECTIVE

In the liver, the transcription factor, Kruppel-like factor 2 (KLF2), is induced early during progression of cirrhosis to lessen the development of vascular dysfunction; nevertheless, its endogenous expression results insufficient to attenuate establishment of portal hypertension and aggravation of cirrhosis. Herein, we aimed to explore the effects and the underlying mechanisms of hepatic KLF2 overexpression in in vitro and in vivo models of liver cirrhosis.

DESIGN

Activation phenotype was evaluated in human and rat cirrhotic hepatic stellate cells (HSC) treated with the pharmacological inductor of KLF2 simvastatin, with adenovirus codifying for this transcription factor (Ad-KLF2), or vehicle, in presence/absence of inhibitors of KLF2. Possible paracrine interactions between parenchymal and non-parenchymal cells overexpressing KLF2 were studied. Effects of in vivo hepatic KLF2 overexpression on liver fibrosis and systemic and hepatic haemodynamics were assessed in cirrhotic rats.

RESULTS

KLF2 upregulation profoundly ameliorated HSC phenotype (reduced α-smooth muscle actin, procollagen I and oxidative stress) partly via the activation of the nuclear factor (NF)-E2-related factor 2 (Nrf2). Coculture experiments showed that improvement in HSC phenotype paracrinally ameliorated liver sinusoidal endothelial cells probably through a vascular endothelial growth factor-mediated mechanism. No paracrine interactions between hepatocytes and HSC were observed. Cirrhotic rats treated with simvastatin or Ad-KLF2 showed hepatic upregulation in the KLF2-Nrf2 pathway, deactivation of HSC and prominent reduction in liver fibrosis. Hepatic KLF2 overexpression was associated with lower portal pressure (-15%) due to both attenuations in the increased portal blood flow and hepatic vascular resistance, together with a significant improvement in hepatic endothelial dysfunction.

CONCLUSIONS

Exogenous hepatic KLF2 upregulation improves liver fibrosis, endothelial dysfunction and portal hypertension in cirrhosis.

Curcumin binds in silico to anti-cancer drug target enzyme MMP-3 (human stromelysin-1) with affinity comparable to two known inhibitors of the enzyme

In silico interaction of curcumin with the enzyme MMP-3 (human stromelysin-1) was studied by molecular docking using AutoDock 4.2 as the docking software application. AutoDock 4.2 software serves as a valid and acceptable docking application to study the interactions of small compounds with proteins. Interactions of curcumin with MMP-3 were compared to those of two known inhibitors of the enzyme, PBSA and MPPT. The calculated free energy of binding (ΔG binding) shows that curcumin binds with affinity comparable to or better than the two known inhibitors. Binding interactions of curcumin with active site residues of the enzyme are also predicted. Curcumin appears to bind in an extendended conformation making extensive VDW contacts in the active site of the enzyme. Hydrogen bonding and pi-pi interactions with key active site residues is also observed. Thus, curcumin can be considered as a good lead compound in the development of new inhibitors of MMP-3 which is a potential target of anticancer drugs. The results of these studies can serve as a starting point for further computational and experimental studies.

Hepatoprotective effect of oral application of a silymarin extract in carbon tetrachloride-induced hepatotoxicity in rats

Background

Silymarin derived from the milk thistle plant “Silybum marianum” is composed of four major flavonolignans. Clinical as well as experimental studies indicate hepatoprotective effects of silymarin. However, the underlying mechanisms are only incompletely understood.

The aim of this study was to assess the effect of oral administration of a defined silymarin extract in the model of acute carbon tetrachloride (CCl4) induced liver injury.

Methods

A single dose of a silymarin extract (SE; 20 or 100 mg/kg body weight) was given to rats by oral gavage. Subsequently, rats were injected with a single dose of CCl4 (2 ml/kg body weight).

Results

After 24h, analysis of liver to body weight ratio, serum levels of transaminases and histological analysis revealed a marked liver damage which was inhibited by SE in a dose dependent manner. CCl4-induced expressions of pro-inflammatory and pro-fibrogenic genes were significantly reduced in SE treated rats. Molecular analysis revealed that SE reduced the expression of the pro-inflammatory chemokine MCP-1, the pro-fibrogenic cytokine TGF-beta as well as collagen I in isolated human hepatic stellate cells (HSC), which are the key effector cells of hepatic fibrosis.

Conclusion

Oral administration of the tested silymarin extract inhibited hepatocellular damage in a model of acute liver injury. Moreover, we newly found that the silymarin extract had direct effects on pro-inflammatory and pro-fibrogenic gene expression in HSCs in vitro. This indicates that direct effects on HSC also contribute to the in vivo hepatoprotective effects of silymarin, and further promote its potential as anti-fibrogenic agent also in chronic liver disease.

Intraperitoneal application of phospholipids for the prevention of postoperative adhesions: a possible role of myofibroblasts

BACKGROUND

Peritoneal adhesions, organized as fibrous bands after abdominal surgery, are related with considerable morbidity and repeated hospitalization. Phospholipids, natural constituents of the peritoneal fluid, seem to display excellent antiadhesive properties. The aim of this study was to investigate whether intraperitoneal application of phospholipids is capable of reducing postoperative adhesions and the possible underlying mechanisms.

MATERIALS AND METHODS

Twenty male Wistar rats were subjected to a midline laparotomy and a standard peritoneal and cecum abrasion trauma. Before laparotomy closure, a bolus of 3 mL of phospholipids (12 mg/mL) or NaCl (placebo) was given intraperitoneally. Seven days later, the quality and the quantity of adhesions, as well as serum proinflammatory and/or profibrotic mediators, were blindly assessed. Human colonic subepithelial myofibroblasts were isolated from normal controls and cultured with transforming growth factor-β1 (TGFβ1, 5 ng/mL) in the presence of phospholipids (30-300 μg/mL). Collagen production in culture supernatants and migratory activity of myofibroblasts were also assessed.

RESULTS

Phospholipids reduced intra-abdominal adhesions (P < 0.001), with respect to their intensity and area, and serum levels of cytokines (interleukin 1β, interleukin 6, platelet-derived growth factor-1, and TGFβ1) compared with placebo-treated rats. Stimulation of myofibroblasts with TGFβ1 significantly increased (P < 0.001) the basic collagen production. The presence of phospholipids significantly reduced (P < 0.001) both the TGFβ1 induced and the basic collagen production. Using a wound healing assay, phospholipids were found to reduce the basic and the TGFβ1-induced migration of myofibroblasts in a concentration-dependent manner.

CONCLUSIONS

Intraperitoneal phospholipids might be involved in the prevention of postoperative adhesions formation via the reduction of proinflammatory and/or profibrotic mediators and by inhibiting fibrogenic properties of mesenchymal cells.

Pre-administration of turmeric prevents methotrexate-induced liver toxicity and oxidative stress

BACKGROUND

Methotrexate (MTX) is an antimetabolite broadly used in treatment of cancer and autoimmune diseases. MTX-induced hepatotoxicity limits its application. We investigated hepatoprotective effects of turmeric in MTX-induced liver toxicity.

METHODS

All experiments were performed on male Wistar albino rats that were randomly divided into six groups. Group one received saline orally for 30 days (control group), groups two and three received turmeric extract (100, 200 mg/kg respectively) orally for 30 days, group four received single dose, of MTX IP at day 30, groups five and six received turmeric extract 100 and 200 mg/kg orally respectively for 30 days and single dose of methoterxate IP (20 mg/kg) at day 30. Four days after MTX injection animals were sacrificed and evaluated. Blood ALT and AST (indicators of hepatocyte injury), ALP and bilirubin (markers of biliary function), albumin (reflect liver synthetic function) as well as the plasma TAS concentration (antioxidant defenses) were determined. The cellular antioxidant defense activities were examined in liver tissue samples using SOD, CAT, and GSH-Px for the oxidative stress, and MDA for lipid peroxidation. In addition, liver damage was evaluated histopathologically.

RESULTS

MTX significantly induced liver damage (P<0.05) and decreased its antioxidant capacity, while turmeric was hepatoprotective. Liver tissue microscopic evaluation showed that MTX treatment induced severe centrilobular and periportal degeneration, hyperemia of portal vein, increased artery inflammatory cells infiltration and necrosis, while all of histopathological changes were attenuated by turmeric (200 mg/kg).

CONCLUSION

Turmeric extract can successfully attenuate MTX-hepatotoxicity. The effect is partly mediated through extract's antinflammatory activity.

Simultaneous Activation of Nrf2 and Elevation of Dietary and Endogenous Antioxidant Chemicals for Cancer Prevention in Humans

Despite extensive studies in cancer prevention, the incidence of cancer is increasing. We review studies that have identified several biochemical and genetic defects as well as potential carcinogens in the diet, environmental factors, and lifestyle-related habits. Two of the biochemical abnormalities increased oxidative stress and chronic inflammation, and chronic exposure to carcinogens and mutagens play a significant role in the initiation of multistage carcinogenesis. Therefore, attenuation of these biochemical defects may be useful in reducing the incidence of cancer. Activation of the transcriptional factor called nuclear factor (erythroid-derived 2)-like 2 (Nrf2), which enhances the levels of antioxidant enzymes and phase-2-detoxifying enzymes by complex mechanisms, may be one of the ways to reduce oxidative stress and chronic inflammation. Antioxidant enzymes destroy free radicals by catalysis, whereas phase-2-detoxifying enzymes remove potential carcinogens by converting them to harmless compounds for elimination from the body. However, increasing the levels of antioxidant enzymes by activating Nrf2 may not be sufficient to decrease oxidative stress and chronic inflammation optimally, because antioxidant chemicals, which are decreased in a high oxidative environment, must also be elevated. This review discusses the regulation of activation of Nrf2 and proposes a hypothesis that an elevation of the levels of antioxidant enzymes and dietary and endogenous antioxidant chemicals simultaneously may reduce the incidence of cancer by decreasing oxidative stress and chronic inflammation. The levels of antioxidant chemicals can be increased by supplementation, but increasing the levels of antioxidant enzymes requires activation of Nrf2 by reactive oxygen species (ROS)-dependent and-independent mechanisms. Several phytochemicals and antioxidant chemicals that activate Nrf2 have been identified. This review also describes clinical studies on antioxidants in cancer prevention that have produced inconsistent results. It discusses the possible reasons for the inconsistent results and proposes criteria that should be included in the experimental designs of future clinical studies to obtain consistent results. KEY TEACHING POINTS: • Reducing oxidative stress and chronic inflammation optimally requires an elevation of the levels of antioxidant enzymes and phase-2-detoxifying enzymes as well as dietary and endogenous antioxidant chemicals. • How the levels of antioxidant enzymes and phase-2-detoxifying enzymes are regulated by a nuclear transcriptional factor Nrf2. • How the activation and transcription of Nrf2 is regulated. • Identification of antioxidants that activate Nrf2 by ROS-dependent and-independent mechanisms, those that destroy free radicals by scavenging, and those that exhibit both functions. • Possible reasons for the inconsistent results produced by the previous clinical studies on antioxidants in cancer prevention. • The criteria that should be included in the experimental designs of future clinical studies on antioxidants in cancer prevention in high-risk populations to obtain consistent results.

Curcumin regulates cell fate and metabolism by inhibiting hedgehog signaling in hepatic stellate cells

Accumulating evidence indicates that Hedgehog (Hh) signaling becomes activated in chronic liver injury and plays a role in the pathogenesis of hepatic fibrosis. Hepatic stellate cells (HSCs) are Hh-responsive cells and activation of the Hh pathway promotes transdifferentiation of HSCs into myofibroblasts. Targeting Hh signaling may be a novel therapeutic strategy for treatment of liver fibrosis. We previously reported that curcumin has potent antifibrotic effects in vivo and in vitro, but the underlying mechanisms are not fully elucidated. This study shows that curcumin downregulated Patched and Smoothened, two key elements in Hh signaling, but restored Hhip expression in rat liver with carbon tetrachloride-induced fibrosis and in cultured HSCs. Curcumin also halted the nuclear translocation, DNA binding, and transcription activity of Gli1. Moreover, the Hh signaling inhibitor cyclopamine, like curcumin, arrested the cell cycle, induced mitochondrial apoptosis, reduced fibrotic gene expression, restored lipid accumulation, and inhibited invasion and migration in HSCs. However, curcumin's effects on cell fate and fibrogenic properties of HSCs were abolished by the Hh pathway agonist SAG. Furthermore, curcumin and cyclopamine decreased intracellular levels of adenosine triphosphate and lactate, and inhibited the expression and/or function of several key molecules controlling glycolysis. However, SAG abrogated the curcumin effects on these parameters of glycolysis. Animal data also showed that curcumin downregulated glycolysis-regulatory proteins in rat fibrotic liver. These aggregated data therefore indicate that curcumin modulated cell fate and metabolism by disrupting the Hh pathway in HSCs, providing novel molecular insights into curcumin reduction of HSC activation.

Attenuation of carbon tetrachloride-induced hepatic injury with curcumin-loaded solid lipid nanoparticles

BACKGROUND AND OBJECTIVES

Curcumin, an established pleiotropic agent, has potential for hepatoprotection owing to its powerful antioxidant, anti-inflammatory, and antifibrogenic properties. However, its poor bioavailability limits its use in therapeutics. In this study, we aimed to package curcumin into solid lipid nanoparticles (C-SLNs) to improve its bioavailability and compare the efficacy of C-SLNs with that of free curcumin and silymarin, a well-established hepatoprotectant in clinical use, against carbon tetrachloride (CCl4)-induced hepatic injury in rats, post-induction. A self-recovery group to which no treatment was given was also employed for quantifying self-healing of hepatic tissue, if any.

MATERIAL AND METHODS

C-SLNs (particle size 147.6 nm), prepared using a microemulsification technique, were administered to rats post-treatment with CCl4 (1 ml/kg body weight [BW] twice weekly for 2 weeks, followed by 1.5 ml/kg BW twice weekly for the subsequent 2 weeks). The extent of liver damage and repair in terms of histopathology and levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), oxidative stress markers (malondialdehyde, superoxide dismutase, and reduced glutathione) and a pro-inflammatory response marker, tumor necrosis factor (TNF)-α, were determined in both the CCl4 group and the treatment groups.

RESULTS

C-SLNs (12.5 mg/kg) significantly (p < 0.001-0.005) attenuated histopathological changes and oxidative stress, and also decreased induction of ALT, AST, and TNF-α in comparison with free curcumin (100 mg/kg), silymarin (25 mg/kg), and self-recovery groups.

CONCLUSION

Curcumin could be used as a therapeutic agent for hepatic disorders, provided it is loaded into a suitable delivery system.

Protection of curcumin against amyloid-β-induced cell damage and death involves the prevention from NMDA receptor-mediated intracellular Ca2+ elevation

Alzheimer's disease (AD) is one of the common neurodegenerative diseases and amyloid-β (Aβ) is thought to be a key molecule contributing to AD pathology. Recently, curcumin is supposed to be beneficial to AD treatment. This study investigates the inhibitory effects of curcumin on Aβ-induced cell damage and death involving NMDA receptor-mediated intracellular Ca(2+) elevation in human neuroblastoma SH-SY5Y cells. Cells were impaired significantly in Aβ-damaged group compared with the control group, and cell viability was decreased while the released LDH from the cytosol was increased. Curcumin promotes cell growth and decreases cell impairment induced by Aβ. Curcmin attenuates Aβ-induced elevation of the ratio of cellular glutamate/γ-aminobutyric acid (GABA) with a concentration-dependent manner. Curcumin inhibits Aβ-induced increase of cellular Ca(2+) and depresses Aβ-induced phosphorylations of both NMDA receptor and cyclic AMP response element-binding protein (CREB) and activating transcription factor 1 (ATF-1). These results indicated that curcumin inhibits Aβ-induced neuronal damage and cell death involving the prevention from intracellular Ca(2+) elevation mediated by the NMDA receptor.

Curcumin targets multiple pathways to halt hepatic stellate cell activation: updated mechanisms in vitro and in vivo

Nonalcoholic steatohepatitis (NASH) is the advanced form of nonalcoholic fatty liver disease, which is often accompanied by obese and/or type II diabetes mellitus. Approximately one-third of NASH patients develop hepatic fibrosis. Hepatic stellate cells are the major effector cells during liver fibrogenesis. Advanced liver fibrosis usually proceeds to cirrhosis and even hepatocellular carcinoma, leading to liver failure, portal hypertension and even death. Currently, there are no approved agents for treatment and prevention of liver fibrosis in human beings. Curcumin, the principal curcuminoid of turmeric, has been reported to show antitumor, antioxidant, and anti-inflammatory properties both in in vitro and in vivo systems. Accumulating data shows that curcumin plays a critical role in combating liver fibrogenesis. This review will discuss the inhibitory roles of curcumin and update the underlying mechanisms by which curcumin targets in inhibiting hepatic stellate cell activation.

Toxicological and biochemical studies on Schinus terebinthifolius concerning its curative and hepatoprotective effects against carbon tetrachloride-induced liver injury

BACKGROUND

Recently, many efforts have been made to discover new products of natural origin which can limit the xenobiotic-induced hepatic injury. Carbon tetrachloride (CCl4) is a highly toxic chemical that is widely used to study hepatotoxicity in animal models.

OBJECTIVE

The present study was conducted to investigate the curative and protective effects of Schinus terbenthifolius ethanolic extract against CCl4 -induced acute hepatotoxicity in rats.

MATERIALS AND METHODS

S. terbenthifolius extract was orally administered in a dose of 350 mg dried extract/kg b.wt. before and after intoxication with CCl4 for curative and protective experiments, respectively. A group of hepatotoxicity indicative enzymes, oxidant-antioxidant capacity, DNA oxidation, and apoptosis markers were measured.

RESULTS

CCl4 increased liver enzyme leakage, oxidative stress, hepatic apoptosis, DNA oxidation, and inflammatory markers. Administration of S. terebinthifolius, either before or after CCl4 intoxication, significantly decreased elevated serum liver enzymes and reinstated the antioxidant capacity. Interestingly, S. terebinthifolius extract inhibited hepatocyte apoptosis as revealed by approximately 20 times down-regulation in caspase-3 expression when compared to CCl4 untreated group. On the other hand, there was neither protective nor curative effect of S. terebinthifolius against DNA damage caused by CCl4.

CONCLUSION

The present study suggests that S. terebinthifolius extract could be a substantially promising hepatoprotective agent against CCl4 toxic effects and may be against other hepatotoxic chemical or drugs.

Effect of various levels of dietary curcumin on meat quality and antioxidant profile of breast muscle in broilers

The aim of this study was to determine the effects of curcumin on meat quality and antioxidant profile of breast muscle in broilers. In experiment 1, birds were fed basal diet with an additional 0, 50, 100, or 200 mg/kg curcumin, respectively. The results showed that dietary curcumin significantly increased the redness values of meat, catalase activity, and ABTS radical scavenging activity and decreased drip loss at 48 h. In experiment 2, birds reared under heat stress were assigned to similar treatments as experiment 1. Significant differences in the redox status of breast muscle were observed between the control and heat stress groups. The various levels of curcumin significantly prevented reactive oxygen species overproduction, enhanced the antioxidant defense system, and alleviated the abnormal change of antioxidant-related gene expression of muscle in heat-stressed birds. It was concluded that curcumin, as a potential antioxidant, improved meat quality and oxidant stability of muscle in broilers, whereas the inclusion of 50 and 100 mg/kg would be more efficient.

Liver fibrosis and mechanisms of the protective action of medicinal plants targeting inflammation and the immune response

Inflammation is a central feature of liver fibrosis as suggested by its role in the activation of hepatic stellate cells leading to extracellular matrix deposition. During liver injury, inflammatory cells are recruited in the injurious site through chemokines attraction. Thus, inflammation could be a target to reduce liver fibrosis. The pandemic trend of obesity, combined with the high incidence of alcohol intake and viral hepatitis infections, highlights the urgent need to find accessible antifibrotic therapies. Medicinal plants are achieving popularity as antifibrotic agents, supported by their safety, cost-effectiveness, and versatility. The aim of this review is to describe the role of inflammation and the immune response in the pathogenesis of liver fibrosis and detail the mechanisms of inhibition of both events by medicinal plants in order to reduce liver fibrosis.

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.

Curcumin improves liver damage in male mice exposed to nicotine

The color of turmeric (薑黃 jiāng huáng) is because of a substance called curcumin. It has different pharmacological effects, such as antioxidant and anti-inflammatory properties. Nicotine is a major pharmacologically active substance in cigarette smoke. It is mainly metabolized in the liver and causes devastating effects. This study was designed to evaluate the protective role of curcumin against nicotine on the liver in mice.

Forty-eight mice were equally divided into eight groups; control (normal saline), nicotine (2.5 mg/kg), curcumin (10, 30, and 60 mg/kg) and curcumin plus nicotine-treated groups. Curcumin, nicotine, and curcumin plus nicotine (once a day) were intraperitoneally injected for 4 weeks. The liver weight and histology, aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and serum nitric oxide levels have been studied.

The results indicated that nicotine administration significantly decreased liver weight and increased the mean diameter of hepatocyte, central hepatic vein, liver enzymes level, and blood serum nitric oxide level compared with the saline group (p < 0.05). However, curcumin and curcumin plus nicotine administration substantially increased liver weight and decreased the mean diameter of hepatocyte, central hepatic vein, liver enzymes, and nitric oxide levels in all groups compared with the nicotine group (p < 0.05).

Curcumin demonstrated its protective effect against nicotine-induced liver toxicity.

The effect of curcumin on liver fibrosis in the rat model of microsurgical cholestasis

We aimed to determine the effects of curcumin on liver fibrosis and to clarify the role of nuclear factor-κB (NF-κB) and inducible nitric oxide synthase (iNOS) in a model of microsurgical cholestasis in the early stage of extrahepatic biliary atresia.

Protective mechanisms of medicinal plants targeting hepatic stellate cell activation and extracellular matrix deposition in liver fibrosis

During chronic liver injury, hepatic stellate cells (HSC) are activated and proliferate, which causes excessive extracellular matrix (ECM) deposition, leading to scar formation and fibrosis. Medicinal plants are gaining popularity as antifibrotic agents, and are often safe, cost-effective, and versatile. This review aims to describe the protective role and mechanisms of medicinal plants in the inhibition of HSC activation and ECM deposition during the pathogenesis of liver fibrosis. A systematic literature review on the anti-fibrotic mechanisms of hepatoprotective plants was performed in PubMed, which yielded articles about twelve relevant plants. Many of these plants act via disruption of the transforming growth factor beta 1 signaling pathway, possibly through reduction in oxidative stress. This reduction could explain the inhibition of HSC activation and reduction in ECM deposition. Medicinal plants could be a source of anti-liver fibrosis compounds.

Curcumin regulates peroxisome proliferator-activated receptor-γ coactivator-1α expression by AMPK pathway in hepatic stellate cells in vitro

Curcumin exerts an inhibitory effect on hepatic stellate cell (HSC) activation, a key step for liver fibrogenesis, and on liver fibrosis by up-regulation of peroxisome proliferator-activated receptor-γ (PPARγ) expression. PPARγ plays a crucial role in suppression of HSC activation. Peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) functions as a co-activator for PPARγ. Therefore, researches on the effect of curcumin on PGC-1α might contribute to understanding of the mechanisms underlying curcumin inhibition of HSC activation and liver fibrosis through PPARγ. The present study aimed to investigate the effect of curcumin on PGC-1α expression in HSCs in vitro and examine the underlying molecular mechanisms by western blot, reat-time PCR, and transfection. Our results showed that curcumin stimulation increased PGC-1α expression and the effects of curcumin on PGC-1α expression were correlated with the activation of adenosine monophosphate-activated protein kinase (AMPK). Curcumin increased superoxide dimutase-2 (SOD2) transcription and activity by AMPK/PGC-1α axis. Moreover, PGC-1α was demonstrated to inhibit α1(I) collagen (a marker for liver fibrosis) transcription in cultured HSCs. These results demonstrated the promotion effect of curcumin on PGC-1α expression through AMPK pathway, which led to the increases in PPARγ activity and in SOD-2 transcription and activity. These data might suggest a possible new explanation for the inhibitory effect of curcumin on HSC activation and on liver fibrogenesis.

The protective effect of curcumin administration on carbon tetrachloride (CCl4)-induced nephrotoxicity in rats

BACKGROUND

The aim of the present study was to examine the protective effect of curcumin (CUR) on carbon tetrachloride (CCl4)-induced nephrotoxicity to evaluate the detailed mechanisms by which CUR exerts its protective action.

METHODS

Thirty male Wistar-Albino rats weighing 250-300 g were randomly divided into three groups: administrations of olive oil (control, po), CCl4 (0.5mg/kg in olive oil sc) every other day for 3 weeks, and CCl4 (0.5mg/kg in olive oil sc) plus CUR (200mg/kg) every day for 3 weeks.

RESULTS

Administration of CCl4 significantly (p<0.001) increased the levels of renal function test such as creatinine and blood urea nitrogen (BUN). Furthermore, treatment of CCl4 significantly elevated the oxidant status of renal tissues while decreasing its anti-oxidant status (p<0.001). CUR displayed a renal protective effect as evident by significant decrease in inflammation and apoptosis during histopathological examination. The administration of CCl4 resulted in an increase in malondialdehyde (MDA) production due to an increase in membrane lipid peroxidation; however, the administration of CUR attenuated this, probably via its antioxidant and free radical scavenging properties.

CONCLUSION

The finding of our study indicates that CUR may have an important role to play in protecting the kidney from oxidative insult.

Curcumin prevents the structural changes induced in the rats' deep cerebellar nuclei by sodium metabisulfite, a preservative agent

OBJECTIVE

To evaluate the the possible neurotoxic effects of sulfite and the protective potential of curcumin on the deep cerebellar nuclei using stereological methods.

METHODS

The rats were randomly divided into five experimental groups (n=6): Group I: distilled water, Group II: Olive oil, Group III: Curcumin (100 mg/kg/day), Group IV: Sodium metabisulfite (25 mg/kg/day), and Group V: Sodium metabisulfite+curcumin. At the end of 56 d, the right cerebellar hemispheres were removed and assigned to stereological studies. The total volume and total neuron number of deep cerebellar nuclei were assessed using Cavalieri and optical disector methods, respectively.

RESULTS

The data showed ∼20% and ∼16% decrease was respectively observed in the total volume and the total neuron number of the deep cerebellar nuclei of the sulfite-treated rats in comparison to the distilled water group (P<0.04). However, no significant change was observed in the total volume and neuronal number of the deep cerebellar nuclei in sulfite+curcumin-treated rats and curcumin played a protective role against sulfite. Curcumin or its vehicle (olive oil) did not induce any significant changes.

CONCLUSIONS

Curcumin, the main part of the turmeric, could prevent the structural changes induced in the deep cerebellar nuclei by sodium metabisulfite, a preservative agent, in rats.

Curcumin attenuates cardiac fibrosis in spontaneously hypertensive rats through PPAR-γ activation

AIM

To investigate the effects of curcumin (Cur) on cardiac fibrosis in spontaneously hypertensive rats (SHRs) and the mechanisms underlying the anti-fibrotic effect of Cur in rat cardiac fibroblasts (CFs) in vitro.

METHODS

SHRs were orally treated with Cur (100 mg·kg(-1)·d(-1)) or Cur (100 mg·kg(-1)·d(-1)) plus the PPAR-γ antagonist GW9662 (1 mg·kg(-1)·d(-1)) for 12 weeks. Cultured CFs were treated with angiotensin II (Ang II, 0.1 μmol/L) in vitro. The expression of relevant proteins and mRNAs was analyzed using Western blotting and real-time PCR, respectively. The expression and activity of peroxisome proliferator-activated receptor-γ (PPAR-γ) were detected using Western blotting and a DNA-binding assay, respectively.

RESULTS

Treatment of SHRs with Cur significantly decreased systolic blood pressure, blood Ang II concentration, heart weight/body weight ratio and left ventricle weight/body weight ratio, with concurrently decreased expression of connective tissue growth factor (CTGF), plasminogen activator inhibitor (PAI)-1, collagen III (Col III) and fibronectin (FN), and increased expression and activity of PPAR-γ in the left ventricle. Co-treatment with GW9662 partially abrogated the anti-fibrotic effects of Cur in SHRs. Pretreatment of CFs with Cur (5, 10, 20 μmol/L) dose-dependently inhibited Ang II-induced expression of CTGF, PAI-1, Col III and FN, and increased the expression and binding activity of PPAR-γ. Pretreatment with GW9662 partially reversed anti-fibrotic effects of Cur in vitro. Furthermore, pretreatment of CFs with Cur inhibited Ang II-induced expression of transforming growth factor-β1 (TGF-β1) and phosphorylation of Smad2/3, which were reversed by GW9662.

CONCLUSION

Cur attenuates cardiac fibrosis in SHRs and inhibits Ang II-induced production of CTGF, PAI-1 and ECM in CFs in vitro. The crosstalk between PPAR-γ and TGF-β1/Smad2/3 signaling is involved in the anti-fibrotic and anti-proliferative effects of Cur.

Protective effects of curcumin and vitamin E against chlorpyrifos-induced lung oxidative damage

There are increasing concerns regarding the toxic effects of chlorpyrifos (CPF) on human health. Curcumin (CUR) is a yellow pigment isolated from turmeric ground rhizome of Curcuma longa Linn., which has been identified as an antioxidant agent. This study was designed to examine the protective effect of CUR and vitamin E (Vit E) on CPF-induced lung toxicity. Rats were divided into seven groups: control, CPF (13.5 mg/kg, orally), CPF + CUR (100 and 300 mg/kg, respectively, orally), CPF + α-tocopherol (Vit E, 150 mg/kg, intraperitoneally), CPF and CUR (100 and 300 mg/kg, respectively) in combination with α-tocopherol. The regimens were administered once daily for 28 days. At the end of the treatment period, lungs were collected for evaluation of oxidative factors and histopathological parameters. CUR and Vit E led to a decrease in lipid peroxidation in the lungs of the CPF-injected animals (48% and 51%, respectively). Glutathione peroxidase inhibited by CPF (91.9 nmol/min/mg protein) was induced again by CUR and Vit E (167.1 and 171.8 nmol/min/mg protein). CUR and Vit E caused a significant induction of superoxide dismutase (103.4 U/mg protein). Catalase activity almost returned to normalcy in CPF-intoxicated rats subjected to CUR + Vit E treatment ( p < 0.001). Lung sections from CPF-treated rats displayed histopathological damages, while coadministration of CUR and Vit E resulted in apparently normal morphology with a significant decrease in injuries ( p < 0.05). Our findings revealed that coadministration of Vit E and CUR to CPF-treated animals prevents the oxidative damages in the lung tissues.

Suppression of the TGF-β/Smad signaling pathway and inhibition of hepatic stellate cell proliferation play a role in the hepatoprotective effects of curcumin against alcohol-induced hepatic fibrosis

The hepatoprotective effects of curcumin against alcohol-induced hepatic fibrosis have rarely been discussed and its mechanisms of action in alcohol-induced liver disease remain unknown. In this study, serum alkaline phosphatase (ALP), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were measured to assess hepatic function; histopathological and immunohistochemical observations were used to evaluate pathological and specific molecular changes in liver tissue and flow cytometry was used to detect the apoptosis in cultured hepatic stellate cells (HSCs), the major fibrogenic cells in the liver; PCR and western blot analysis were employed to evaluate the changes in the expression of molecules and signaling pathways. We demonstrate that curcumin alleviates alcohol-induced hepatic fibrosis by affecting the HSCs. We found that the administration of curcumin inhibited alcohol-induced HSC proliferation and even induced HSC apoptosis by stimulating endoplasmic reticulum (ER) stress. We also found that by suppressing the transforming growth factor-β (TGF-β)/Smad signaling pathway, the administration of curcumin impaired the production of extracellular matrix proteins in alcohol-stimulated HSCs. These results indicate that curcumin exerts its hepatoprotective effects against alcohol-induced hepatic fibrosis by inhibiting the proliferation and inducing the apoptosis of HSCs by stimulating ER stress and deactivating HSCs by suppressing the TGF-β/Smad signaling pathway.

Nanotechnology applications for the therapy of liver fibrosis

Chronic liver diseases represent a major global health problem both for their high prevalence worldwide and, in the more advanced stages, for the limited available curative treatment options. In fact, when lesions of different etiologies chronically affect the liver, triggering the fibrogenesis mechanisms, damage has already occurred and the progression of fibrosis will have a major clinical impact entailing severe complications, expensive treatments and death in end-stage liver disease. Despite significant advances in the understanding of the mechanisms of liver fibrinogenesis, the drugs used in liver fibrosis treatment still have a limited therapeutic effect. Many drugs showing potent antifibrotic activities in vitro often exhibit only minor effects in vivo because insufficient concentrations accumulate around the target cell and adverse effects result as other non-target cells are affected. Hepatic stellate cells play a critical role in liver fibrogenesis , thus they are the target cells of antifibrotic therapy. The application of nanoparticles has emerged as a rapidly evolving area for the safe delivery of various therapeutic agents (including drugs and nucleic acid) in the treatment of various pathologies, including liver disease. In this review, we give an overview of the various nanotechnology approaches used in the treatment of liver fibrosis.

Curcumin affects β-catenin pathway in hepatic stellate cell in vitro and in vivo

OBJECTIVES

Emerging evidence indicates that Wnt/β-catenin pathway is linked to the fibrosis of different organs including liver fibrosis. β-Catenin promotes hepatic stellate cells (HSCs) activation, a key event in the development of liver fibrosis, and has emerged as a novel mediator of fibrosis. Curcumin, a natural active ingredient derived from turmeric, possesses an inhibitory effect on liver fibrosis. This study is aimed to examine whether curcumin affects β-catenin expression/activity in HSCs and explores the underlying mechanisms.

METHODS

The researchers used Western blot, real-time PCR, transfection assay and electrophoretic mobility shift assay and employed cultured HSCs and rat model of liver injury.

KEY FINDINGS

Results showed that curcumin could reduce β-catenin protein level in HSCs in vitro and in vivo. Both β-catenin transactivation activity and DNA-binding activity were suppressed by curcumin. Moreover, nuclear β-catenin protein level was decreased by curcumin treatment. Further experiments suggested that delta-like homologue 1 contributed to curcumin inhibition of β-catenin transactivation activity in cultured HSCs.

CONCLUSIONS

Curcumin affects β-catenin pathway in HSCs and might suggest a possible new explanation for the effects of curcumin on HSC activation and liver fibrosis.

Curcumin eliminates the effect of advanced glycation end-products (AGEs) on the divergent regulation of gene expression of receptors of AGEs by interrupting leptin signaling

Non-alcoholic steatohepatitis (NASH) is a major risk factor for hepatic fibrogenesis. NASH is often found in diabetic patients with hyperglycemia. Hyperglycemia induces non-enzymatic glycation of proteins, yielding advanced glycation end-products (AGEs). Effects of AGEs are mainly mediated by two categories of cytoplasmic membrane receptors. Receptor for AGEs (RAGE) is associated with increased oxidative stress and inflammation, whereas AGE receptor-1 (AGE-R1) is involved in detoxification and clearance of AGEs. Activation of hepatic stellate cells (HSC) is crucial to the development of hepatic fibrosis. We recently reported that AGEs stimulated HSC activation likely by inhibiting gene expression of AGE-R1 and inducing gene expression of RAGE in HSC, which were eliminated by the antioxidant curcumin. This study is to test our hypothesis that curcumin eliminates the effects of AGEs on the divergent regulation of the two receptors of AGEs in HSC by interrupting the AGE-caused activation of leptin signaling, leading to the inhibition of HSC activation. We observed herein that AGEs activated leptin signaling by inducing gene expression of leptin and its receptor in HSC. Like AGEs, leptin differentially regulated gene expression of RAGE and AGE-R1. Curcumin eliminated the effects of AGEs in HSC by interrupting leptin signaling and activating transcription factor NF-E2 p45-related factor 2 (Nrf2), leading to the elevation of cellular glutathione and the attenuation of oxidative stress. In conclusions, curcumin eliminated the effects of AGEs on the divergent regulation of gene expression of RAGE and AGE-R1 in HSC by interrupting the AGE-caused activation of leptin signaling, leading to the inhibition of HSC activation.

Curcumin attenuates angiogenesis in liver fibrosis and inhibits angiogenic properties of hepatic stellate cells

Hepatic fibrosis is concomitant with sinusoidal pathological angiogenesis, which has been highlighted as novel therapeutic targets for the treatment of chronic liver disease. Our prior studies have demonstrated that curcumin has potent antifibrotic activity, but the mechanisms remain to be elucidated. The current work demonstrated that curcumin ameliorated fibrotic injury and sinusoidal angiogenesis in rat liver with fibrosis caused by carbon tetrachloride. Curcumin reduced the expression of a number of angiogenic markers in fibrotic liver. Experiments in vitro showed that the viability and vascularization of rat liver sinusoidal endothelial cells and rat aortic ring angiogenesis were not impaired by curcumin. These results indicated that hepatic stellate cells (HSCs) that are characterized as liver-specific pericytes could be potential target cells for curcumin. Further investigations showed that curcumin inhibited VEGF expression in HSCs associated with disrupting platelet-derived growth factor-β receptor (PDGF-βR)/ERK and mTOR pathways. HSC motility and vascularization were also suppressed by curcumin associated with blocking PDGF-βR/focal adhesion kinase/RhoA cascade. Gain- or loss-of-function analyses revealed that activation of peroxisome proliferator-activated receptor-γ (PPAR-γ) was required for curcumin to inhibit angiogenic properties of HSCs. We concluded that curcumin attenuated sinusoidal angiogenesis in liver fibrosis possibly by targeting HSCs via a PPAR-γ activation-dependent mechanism. PPAR-γ could be a target molecule for reducing pathological angiogenesis during liver fibrosis.

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.