Evaluation of oxidative stress during apoptosis and necrosis caused by D-galactosamine in rat liver

Pharmacological Activities of Plant-Derived Fraxin with Molecular Mechanisms: A Comprehensive Review

Fruits and vegetables serve not only as sources of nutrition but also as medicinal agents for the treatment of diverse diseases and maladies. These dietary components are significant resources of phytochemicals that demonstrate therapeutic properties against many illnesses. Fraxin is a naturally occurring coumarin glycoside mainly present in various species of Fraxinus genera, having a multitude of therapeutic uses against various diseases and disorders. This study focuses to investigate the pharmacological activities, botanical sources, and biopharmaceutical profile of the phytochemical fraxin based on different preclinical and non-clinical studies to show the scientific evidence and to evaluate the underlying molecular mechanisms of the therapeutic effects against various ailments. For this, data was searched and collected (as of February 15, 2024) in a variety of credible electronic databases, including PubMed/Medline, Scopus, Springer Link, ScienceDirect, Wiley Online, Web of Science, and Google Scholar. The findings demonstrated favorable outcomes in relation to a range of diseases or medical conditions, including inflammation, neurodegenerative disorders such as cerebral ischemia-reperfusion (I/R) and depression, viral infection, as well as diabetic nephropathy. The phytochemical also showed protective effects such as osteoprotective, renoprotective, pulmoprotective, hepatoprotective, and gastroprotective effects due to its antioxidant capacity. Fraxin has a great capability to diminish oxidative stress-related damage in different organs by stimulating the antioxidant enzymes, downregulating nuclear factor kappa B and NLRP3, and triggering the Nrf2/ARE signaling pathways. Fraxin exhibited poor oral bioavailability because of reduced absorption and a wide distribution into tissues of different organs. However, extensive research is required to decipher the biopharmaceutical profiles, and clinical studies are necessary to establish the efficacy of the natural compound as a reliable therapeutic agent.

Biological Evaluation of Photodynamic Effect Mediated by Nanoparticles with Embedded Porphyrin Photosensitizer

Clinically approved photodynamic therapy (PDT) is a minimally invasive treatment procedure that uses three key components: photosensitization, a light source, and tissue oxygen. However, the photodynamic effect is limited by both the photophysical properties of photosensitizers as well as their low selectivity, leading to damage to adjacent normal tissue and/or inadequate biodistribution. Nanoparticles (NPs) represent a new option for PDT that can overcome most of the limitations of conventional photosensitizers and can also promote photosensitizer accumulation in target cells through enhanced permeation and retention effects. In this in vitro study, the photodynamic effect of TPP photosensitizers embedded in polystyrene nanoparticles was observed on the non-tumor NIH3T3 cell line and HeLa and G361 tumor cell lines. The efficacy was evaluated by viability assay, while reactive oxygen species production, changes in membrane mitochondrial potential, and morphological changes before and after treatment were imaged by atomic force microscopy. The tested nanoparticles with embedded TPP were found to become cytotoxic only after activation by blue light (414 nm) due to the production of reactive oxygen species. The photodynamic effect observed in this evaluation was significantly higher in both tumor lines than the effect observed in the non-tumor line, and the resulting phototoxicity depended on the concentration of photosensitizer and irradiation time.

The effect of two porphyrine photosensitizers TMPyP and ZnTPPS4 for application in photodynamic therapy of cancer cells in vitro

Photodynamic therapy (PDT) is one of the treatments for cancer. This therapy uses a combination of a photosensitizer (PS), light irradiation, and oxygen O₂, which is converted to cytotoxic ¹O₂ and other forms of reactive oxygen species (ROS), causing selective damage to the target tissue. In this work, we studied effect of two porphyrin photosensitizers TMPyP and ZnTPPS₄ at three different concentrations (0.25, 0.5, 5μM) after two irradiation doses (5 and 25 J/cm²). Photodynamic efect of TMPyP and ZnTPPS₄ were confirmed by a battery of in vitro tests including MTT, reactive oxygen species (ROS) production and mitochondrial membrane potential test (MMP). Morphological changes of the cells before and after treatment were imaged by atomic force microscopy (AFM). The most effective combination of irradiation dose and concentration for both PSs showed a concentration of 5 μM and a irradiation dose of 25 J/cm² in both cell cultures.

Apoptotic effects of rhein through the mitochondrial pathways, two death receptor pathways, and reducing autophagy in human liver L02 cells

Rhein (4,5-dihydroxyanthraquinone-2-carboxylic acid) is a major component of many medicinal herbs such as Rheum palmatum L. and Polygonum multiflorum. Despite being widely used, intoxication cases associated with rhein-containing herbs are often reported. Currently, there are no available reports addressing the effects of rhein on apoptosis in human liver L02 cells. Thus, the aim of this study is to determine the cytotoxic effects and the underlying mechanism of rhein on human normal liver L02 cells. In the present study, the methyl thiazolyl tetrazolium assay demonstrated that rhein decreased the viability of L02 cells in dose-dependent and time-dependent ways. Rhein was found to trigger apoptosis in L02 cells as shown by Annexin V-fluoresceine isothiocyanate (FITC) apoptosis detection kit and cell mitochondrial membrane potential (MMP) assay, with nuclear morphological changes demonstrated by Hoechst 33258 staining. Detection of intracellular superoxide dismutase activity, lipid oxidation (malondialdehyde) content, and reactive oxygen species (ROS) levels showed that apoptosis was associated with oxidative stress. Moreover, it was observed that the mechanism implicated in rhein-induced apoptosis was presumably via the death receptor pathway and the mitochondrial pathway, as illustrated by upregulation of TNF-α, TNFR1, TRADD, and cleaved caspase-3, and downregulation of procaspase-8, and it is suggested that rhein may increase hepatocyte apoptosis by activating the increase of TNF-α level. Meanwhile, rhein upregulates the expression of Bax and downregulates the expression of procaspase-9 and -3, and it is suggested that the mitochondrial pathway is activated and rhein-induced apoptosis may be involved. In addition, we also want to explore whether rhein-induced apoptosis is related to the autophagic changes induced by rhein. The results showed that rhein treatment increased P62 and decreased LC3-II and beclin-1, which means that autophagy was weakened. The results of our studies indicated that rhein induced caspase-dependent apoptosis via both the Fas death pathway and the mitochondrial pathway by generating ROS, and meanwhile the autophagy tended to weaken.

Chemical induction of hepatic apoptosis in rodents

The urge of identifying new pharmacological interventions to prevent or attenuate liver injury is of critical importance and needs an expanded experimental toolbox. Hepatocyte injury and cellular death is a prominent feature behind the pathology of liver diseases. Several research activities focused on identifying chemicals and hepatotoxicants that induce cell death by apoptosis, in addition to presenting its corresponding signaling pathway. Although such efforts provided further understanding of the mechanisms of cell death, it has also raised confusion concerning identifying the involvement of several modes of cell death including apoptosis, necrosis and fibrosis. The current review highlights the ability of several chemicals and potential hepatotoxicants to induce liver damage in rodents by means of apoptosis while the probable involvement of other modes of cell death is also exposed. Thus, several chemical substances including hepatotoxins, mycotoxins, hyperglycemia inducers, metallic nanoparticles and immunosuppressant drugs are reviewed to explore the hepatic cytotoxic spectrum they could exert on hepatocytes of rodents. In addition, the current review address the mechanism by which hepatotoxicity is initiated in hepatocytes in different rodents aiding the researcher in choosing the right animal model for a better research outcome.

Effects of low dose of aliskiren on isoproterenol-induced acute myocardial infarction in rats

This study examined the effects of aliskiren (Ali) (direct renin inhibitor) on serum cardiac enzymes (LDH and CK-MB), electrocardiography (ECG) changes, myocardial oxidative stress markers (MDA, CAT, and GSH) and the expression of Bcl2, HO-1, and Nrf2 genes in isoproterenol (ISO)-induced myocardial infarction (MI). A total of 40 male albino rats were allocated into four groups, (1) normal control (NC) group, (2) Ali group (rats received Ali at 10 mg/kg/day p.o. for 5 days), (3) ISO group (rats received ISO 150 mg/kg i.p. for two consecutive days at 24 h intervals), and (4) Ali + ISO group (rats received ISO + Ali at 10 mg/kg/day p.o. for 5 days from the 2^nd dose of ISO). ISO group showed significant rise in serum cardiac enzymes (CK-MB and LDH), myocardial damage scores, myocardial MDA, HO-1, myocardial Nrf2 expression with significant reduction in myocardial antioxidants (CAT and GSH), and Bcl2 expression compared to the normal group (p < 0.05). ECG showed ST segment elevation, prolonged QT interval and QRS complex, and increased heart rate in ISO group. Co-administration of Ali and ISO caused significant increase in cardiac enzymes and morphology with increase in MDA, serum K, and creatinine with significant decrease in Bcl2, HO-1, and Nrf2 without significant changes in ECG parameters compared to ISO group. We concluded that low dose of Ali seems to exacerbate the myocardial injury in ISO-MI, which might be due to the enhanced oxidative stress and apoptosis.

Cytotoxic effects of Aeromonas hydrophila culture supernatant on peripheral blood leukocytes of Nile tilapia (Oreochromis niloticus): Possible presence of a secreted cytotoxic lectin

Number of exotoxins like haemolysin, leukocidin, aerolysin etc. were reported from Aeromonas hydrophila. In this study, we report the haemolytic and cytotoxic effect of A. hydrophila culture supernatant (CS) that is specifically inhibited by lactose and also by serum and mucus of Nile tilapia (Oreochromis niloticus). Hence, we assume the presence of a secreted lectin in the CS. CS is toxic to peripheral blood leukocytes (PBL) of O. niloticus as revealed by MTT assay and by flow cytometry. DNA laddering assay indicates that CS causes necrosis to PBL. As a result of necrosis, CS treated PBL showed increased production of reactive oxygen species as indicated by nitroblue tetrazolium and 2',7' -dichlorofluorescin diacetate assays. CS treated PBL showed reduced mRNA expression of TNF-α and IFN-γ genes. When CS was subjected to polyacrylamide gel electrophoresis, it showed a single band corresponding to the molecular weight of 45 kDa. However, upon concentrating the CS by ultrafiltration, many bands were visualized. Further studies at molecular level are required to unravel this macromolecular-leukocyte interaction which would ultimately benefit the aquaculture industry.

Effect of protocatechuic acid on lipid profile and DNA damage in D-galactosamine-induced hepatotoxic rats

BACKGROUND

Our aim in this study is to investigate the effect of protocatechuic acid (PCA) on lipid profile and DNA damage in D-galactosamine (D-GalN)-induced hepatotoxic rats.

METHODS

Hepatotoxicity was induced by a single intraperitoneal dose of D-GalN in male Wistar rats. The activities of hepatic markers and levels of kidney function markers were determined. The plasma and tissue lipid levels were estimated. DNA damage was determined by COMET assay. Histopathological examination was also performed using portions of the liver and kidney tissues.

RESULTS

D-GalN-induced hepatotoxic rats showed increased in the activities of hepatic marker enzymes such as aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and γ-glutamyl transpeptidase (GGT) in serum. The levels of kidney function markers such as urea, uric acid, and creatinine increased in serum. Levels of lipid profile such as total cholesterol (TC), triglycerides (TG), free fatty acid (FFA), and phospholipids (PLs) in the plasma and tissues (liver and kidney) were significantly increased in D-GalN-induced rats. In plasma, levels of very low density lipoprotein cholesterol (VLDL-C) and low-density lipoprotein cholesterol (LDL-C) significantly increased, whereas high-density lipoprotein cholesterol (HDL-C) level decreased in D-GalN-induced rats. Furthermore, D-GalN-induced rats showed increased percentage of tail DNA and tail length and decreased percentage of head DNA. Oral administration of PCA (100 mg/ kg BW) for 20 days improved these levels when compared to D-GalN-induced rats. These biochemical changes were reflected on the attenuation and the structural alteration of the liver and kidney integrity.

CONCLUSIONS

The results of the study suggest that PCA has a potent hepatoprotective activity that may be linked to its antihyperlipidemic effect.

The effects of pentoxifylline and caffeic acid phenethyl ester in the treatment of d-galactosamine-induced acute hepatitis in rats

The aim of this study was to investigate histological changes in hepatic tissue and effects of pentoxifylline (PTX) and caffeic acid phenethyl ester (CAPE) on these changes using histochemical and biochemical methods in rats, in which hepatitis was established by D-galactosamine (D-GAL). Rats were divided into five groups as follows: control group, D-GAL (24 h) group, D-GAL group, d-GAL + PTX group, and D-GAL + CAPE group. In histological evaluations, the control group showed normal appearance of the liver cells. However in the d-GAL groups, focal areas consisting of inflammatory, necrotic, and apoptotic cells were detected in parenchyma. Glycogen loss was observed in the hepatocytes localized at the periphery of lobule. It was found that number of mast cells of portal areas were significantly higher in D-GAL groups compared with other groups (p = 0.0001). In addition, the number of cells with positive staining by Ki-67 and caspase-3 were significantly increased in GAL groups compared with the control group (p = 0.0001). In biochemical analysis, there was an increase in malondialdehyde and myeloperoxidase levels, while a decrease was observed in glutathione level and glutathione peroxidase activity in groups treated with d-GAL compared with the control group. On the other hand, it was seen that, in the groups treated with D-GAL, histological and biochemical injuries in the liver were reduced by administration of PTX and CAPE. In this study, we demonstrated the ameliorative effects of PTX and CAPE on D-GAL-induced liver injury.

Metabolite profiling and pathway analysis of acute hepatitis rats by UPLC-ESI MS combined with pattern recognition methods

BACKGROUND & AIMS

Metabolomics is comprehensive analysis of low-molecular-weight endogenous metabolites in a biological sample. It could enable mapping of perturbations of early biochemical changes in diseases and hence provide an opportunity to develop predictive biomarkers that could provide valuable insights into the mechanisms of diseases. The aim of this study was to elucidate the changes in endogenous metabolites and to phenotype the metabolic profiling of d-galactosamine (GalN)-inducing acute hepatitis in rats by UPLC-ESI MS.

METHODS

The systemic biochemical actions of GalN administration (ip, 400 mg/kg) have been investigated in male wistar rats using conventional clinical chemistry, liver histopathology and metabolomic analysis of UPLC- ESI MS of urine. The urine was collected predose (-24 to 0 h) and 0-24, 24-48, 48-72, 72-96 h post-dose. Mass spectrometry of the urine was analysed visually and via conjunction with multivariate data analysis.

RESULTS

Results demonstrated that there was a time-dependent biochemical effect of GalN dosed on the levels of a range of low-molecular-weight metabolites in urine, which was correlated with developing phase of the GalN-inducing acute hepatitis. Urinary excretion of beta-hydroxybutanoic acid and citric acid was decreased following GalN dosing, whereas that of glycocholic acid, indole-3-acetic acid, sphinganine, n-acetyl-l-phenylalanine, cholic acid and creatinine excretion was increased, which suggests that several key metabolic pathways such as energy metabolism, lipid metabolism and amino acid metabolism were perturbed by GalN.

CONCLUSION

This metabolomic investigation demonstrates that this robust non-invasive tool offers insight into the metabolic states of diseases.

Quantitative proteomic analysis of hepatocyte-secreted extracellular vesicles reveals candidate markers for liver toxicity

Extracellular vesicles have created great interest as possible source of biomarkers for different biological processes and diseases. Although the biological function of these vesicles is not fully understood, it is clear that they participate in the removal of unnecessary cellular material and act as carriers of various macromolecules and signals between the cells. In this report, we analyzed the proteome of extracellular vesicles secreted by primary hepatocytes. We used one- and two-dimensional liquid chromatography combined with data-independent mass spectrometry. Employing label-free quantitative proteomics, we detected significant changes in vesicle protein expression levels in this in vitro model after exposure to well-known liver toxins (galactosamine and Escherichia coli-derived lipopolysaccharide). The results allowed us to identify candidate markers for liver injury. We validated a number of these markers in vivo, providing the basis for the development of novel methods to evaluate drug toxicity. This report strongly supports the application of proteomics in the study of extracellular vesicles released by well-controlled in vitro cellular systems. Analysis of such systems should help to identify specific markers for various biological processes and pathological conditions.

BIOLOGICAL SIGNIFICANCE

Identification of low invasive candidate marker for hepatotoxicity. Support to apply proteomics in the study of extracellular vesicles released by well-controlled in vitro cellular systems to identify low invasive markers for diseases.

Role of connexin 32 in acetaminophen toxicity in a knockout mice model

Gap junctional intercellular communication (GJIC), by which glutathione (GSH) and inorganic ions are transmitted to neighboring cells, is recognized as being largely involved in toxic processes of chemicals. We examined acetaminophen (APAP)-induced hepatotoxicity clinicopathologically using male wild-type mice and mice lacking the gene for connexin32, a major gap junction protein in the liver [knockout (Cx32KO) mice]. When APAP was intraperitoneally administered at doses of 100, 200, or 300mg/kg, hepatic centrilobular necrosis with elevated plasma aminotransferase activities was observed in wild-type mice receiving 300mg/kg, and in Cx32KO mice given 100mg/kg or more. At 200mg/kg or more, hepatic GSH and GSSG contents decreased significantly and the effect was more severe in wild-type mice than in Cx32KO mice. On the other hand, markedly decreased GSH staining was observed in the hepatic centrilobular zones of Cx32KO mice compared to that of wild-type mice. These results demonstrate that Cx32KO mice are more susceptible to APAP hepatotoxicity than wild-type mice, and indicate that the distribution of GSH of the centrilobular zones in the hepatic lobules, rather than GSH and GSSG contents in the liver, is important in APAP hepatotoxicity. In conclusion, Cx32 protects against APAP-induced hepatic centrilobular necrosis in mice, which may be through the GSH transmission to neighboring hepatocytes by GJIC.

Effect of lycopene on oxidative stress induced during D-galactosamine/lipopolysaccharide-sensitized liver injury in rats

CONTEXT

Lycopene is a phytonutrient under considerable investigation for its antioxidant benefits in treating diseases like cancer, cardiovascular diseases, osteoporosis and diabetes.

OBJECTIVE

This study explores the effect of lycopene against oxidative damage during experimental hepatitis, induced by D-galactosamine/lipopolysaccharide (D-GalN/LPS).

MATERIALS AND METHODS

Experimental rats were pretreated with lycopene intraperitoneally for 6 d (10 mg/kg body weight/day) and then induced by D-GalN/LPS. After induction, the levels of lipid peroxides in serum and liver of control and experimental group of animals were measured. The activities of enzymatic antioxidants such as superoxide dismutase, catalase, glutathione peroxidase and glutathione S-transferase and nonenzymatic antioxidants, such as reduced glutathione, vitamin C and vitamin E were also analyzed. The genotoxic effect of D-GalN/LPS was evaluated through the comet assay.

RESULTS

The elevated level of lipid peroxides induced by D-GalN/LPS was significantly (p < 0.05) reverted in lycopene pretreated animals. Lycopene administration restored (p < 0.05) the decreased activities of enzymatic and nonenzymatic antioxidant markers during D-GalN/LPS induction. The DNA strand breaks (72.3 μM) generated during d-GalN/LPS toxic injury was significantly reduced (35.5 μM) upon pretreatment with lycopene as observed by reduced tail movement in comet assay.

DISCUSSION AND CONCLUSION

There is no conclusive report about lycopene-assisted protection against free radical mediated toxic injury induced by D-GalN/LPS. Our findings reveal that lycopene effectively combated oxidative damage and protected antioxidant defense status of the cell. Pretreatment of lycopene also offers protection against the DNA damage and confirms the antioxidant nature of the phytonutreint against experimental hepatitis.

β-Nerve growth factor attenuates hepatocyte injury induced by D-galactosamine in vitro via TrkA NGFR

Nerve growth factor (NGF) regulates the proliferation, differentiation and survival of cells and is also involved in the wound healing and tissue remodeling processes. The biological effects of NGF are dependent upon receptor signal-mediating functions, which differ between cells. This study attempted to investigate the hepatoprotective effect and possible mechanism of β-NGF on D-galactosamine (D-GalN)-injured human liver L-02 cell lines. We demonstrated that L-02 cells expressed the neurotrophin receptors tyrosine kinase-A nerve growth factor receptor (TrkA NGFR) and p75 pan-neurotrophin receptor (p75NTR). Recombinant human β-NGF markedly reduced cell injury and promoted the proliferation of L-02 cells damaged by D-GalN. However, this proliferation effect was blocked by the anti-TrkA NGFR antibody. Lactate dehydrogenase (LDH) and malondialdehyde (MDA) were released at reduced levels in the L-02 cell culture supernatant pretreated with β-NGF. Furthermore, the albumin (ALB) content in the cell medium and intracellular glutathione (GSH) levels were markedly augmented, and the permeability of the mitochondrial membrane of the L-02 cells was improved by β-NGF. Our results suggested that exogenous β-NGF protects L-02 cells from D-GalN-induced injury through the NGF/TrkA NGFR signaling pathway.

The involvement of heme oxygenase 1 but not nitric oxide synthase 2 in a hepatoprotective action of quercetin in lipopolysaccharide-induced hepatotoxicity of D-galactosamine sensitized rats

The objective of this study was to evaluate potential hepatoprotective capabilities of quercetin in relation to its modulation of the HO-1 and NOS-2 activities in an experimental model of fulminant liver failure. Liver insult was induced by in vivo administration of D-galactosamine (d-GalN, 400 mg/kg, i.p.) and lipopolysaccharide (LPS, 10 μg/kg, i.p.). The effects of quercetin (50 mg/kg, i.p) on D-GalN toxicity was evaluated by standard biochemical, RT-PCR and Western blot methods. Administration of d-GalN/LPS combination resulted in significantly higher plasma levels of aminotransferases, as well as increased mRNA and protein expressions of both HO-1 and NOS-2 enzymes. Quercetin exhibited cytoprotective effects on the liver, as evidenced by decreased aminotransferase plasma levels. Additionally, quercetin treatment in D-GalN/LPS treated rats significantly increased HO-1 mRNA and its protein expressions. On the contrary, quercetin did not exhibit any significant effects on the levels of nitrites, and NOS-2 mRNA and protein expressions in D-GalN/LPS treated rats. Quercetin when given alone did not have any significant changes on liver enzymes nor HO-1 and NOS-2 mRNA and protein expressions. It can be concluded that the quercetin's induction of HO-1 and its byproducts, without concomitant NOS-2 activity reduction, is among mechanisms contributing to the hepatoprotective effect in D-GalN/LPS hepatotoxicity.

Effects of globin digest and its active ingredient Trp-Thr-Gln-Arg on galactosamine/lipopolysaccharide-induced liver injury in ICR mice

AIMS

We investigated the effects of globin digest (GD) and its active ingredient Trp-Thr-Gln-Arg (WTQR) on galactosamine/lipopolysaccharide (GalN/LPS)-induced liver injury in imprinting control region (ICR) mice.

MAIN METHODS

The effects of WTQR and GD on the liver injury were examined by measuring the survival rate, serum aminotransferase activities, hepatic components, antioxidant enzyme activities, histopathological analysis, serum levels and hepatic gene expression of tumor necrosis factor-alpha (TNF-α), macrophage inflammatory protein-2 (MIP-2), and nitric oxide (NO) or inducible nitric oxide synthase (iNOS), and nuclear factor-kappa B (NF-κB) p65 content in GalN/LPS-treated ICR mice. RAW264 mouse macrophages were used to confirm the anti-inflammatory effects of WTQR and GD on the macrophages.

KEY FINDINGS

WTQR and GD increased the survival rate, suppressed the serum aminotransferase activities, serum levels and hepatic gene expression of TNF-α, MIP-2, and NO or iNOS, and nuclear NF-κB p65 content in GalN/LPS-treated mice; decreased the oxidized glutathione content, increased the superoxide dismutase activity, and decreased the histopathological grade values of the hepatocyte necrosis and lobular inflammation in GalN/LPS-injured liver; and suppressed the release levels and gene expression of TNF-α, MIP-2, and NO or iNOS, and nuclear NF-κB p65 content in LPS-stimulated RAW264 macrophages. WTQR and GD may improve the antioxidant defense system and inflammatory status in GalN/LPS-injured liver.

SIGNIFICANCE

These findings indicate that WTQR and GD have hepatoprotective effects on GalN/LPS-induced liver injury in ICR mice.

Cardioprotective effect of fenugreek on isoproterenol-induced myocardial infarction in rats

OBJECTIVES

This study is designed to evaluate the cardioprotective effect of fenugreek on isoproterenol- induced myocardial infarction and is investigated by an in vivo method in rats.

MATERIALS AND METHODS

Male Wistar albino rats were divided into four groups (n=10). Group I received 0.5% CMC treated as normal control group. Group II received isoproterenol (85 mg/kg body weight) intraperitoneal (i.p.) for two consecutive days (14(th) and 15(th) days). Group III received fenugreek (250 mg/kg body weight) intragastric intubation for 15 days. Group IV rats received fenugreek as in Group III and additionally isoproterenol was given for two consecutive days (14(th) and 15(th) days).

RESULTS

The results described the cardioprotective effect that observed in Group IV showed significantly (P< 0.05) decreased levels of TBARS and enhanced the activities of both enzymatic and non-enzymatic antioxidants (SOD, CAT, GPx and GSH) in myocardial infarcted rats when compared to Groups II and III. Histopathological studies were also co-relating with the above biochemical parameters.

CONCLUSION

These findings concluded the cardioprotective effect of fenugreek on lipid peroxidation and antioxidant defense system during isoproterenol-induced myocardial infarction in rats.

Amelioration of D-galactosamine-induced acute liver injury in rats by dietary supplementation with betaine derived from sugar beet molasses

The effects of betaine supplementation on D-galactosamine-induced liver injury were examined in terms of hepatic and serum enzyme activities and of the levels of glutathione and betaine-derived intermediates. The rats induced with liver injury showed marked increases in serum enzyme activity, but those receiving dietary supplementation of 1% betaine showed enzyme activity levels similar to a control group without liver injury. Administration of betaine also increased both hepatic and serum glutathione levels, even following D-galactosamine injection. The activity of glutathione-related enzymes was markedly decreased following injection of D-galactosamine, but remained comparable to that of the control group in rats receiving 1% betaine. The concentrations of hepatic S-adenosyl methionine and cysteine showed similar trends to that observed for hepatic glutathione levels. These results indicate that 1% betaine has a hepatoprotective effect by increasing hepatic and serum glutathione levels along with glutathione-related enzyme activities in rats.

Betulinic acid prevention of d-galactosamine/lipopolysaccharide liver toxicity is triggered by activation of Bcl-2 and antioxidant mechanisms

OBJECTIVES

The hepatoprotective activity and molecular mechanism of betulinic acid (BA) was investigated on acute liver failure induced by d-galactosamine (D-GalN)/lipopolysaccharide (LPS) in vivo.

METHODS

Mice were administered with different doses of BA (20 mg/kg or 50 mg/kg, i.p.) 1 h before injection of D-GalN (700 mg/kg)/LPS (10 µg/kg) and sacrificed 6 h after treatment with D-GalN/LPS.

KEY FINDINGS

Pretreatment with BA significantly prevented the increases of serum aspartate aminotransferase and alanine aminotransferase, while it increased the content of glutathione and catalase, and reduced malondialdehyde. BA showed obvious anti-oxidant effects and prevented D-GalN/LPS-induced apoptosis, as indicated by DNA ladder. BA treatment resulted in regulation of the mitogen-activated protein kinase. We found that BA mediated production of c-jun NH(2) -terminal protein kinase and extracellular signal-regulated kinase induced by D-GalN/LPS, promoted the expression of B-cell CLL/lymphoma 2 (Bcl-2) and restored mitochondrial outer membrane permeabilization.

CONCLUSIONS

The results suggested that BA prevented D-GalN/LPS-induced acute liver failure by upregulation of Bcl-2 and antioxidation and mediation of cytokines causing apoptotic cell death and lessened liver damage.

Effect of globin digest on the liver injury and hepatic gene expression profile in galactosamine-induced liver injury in SD rats

AIMS

We investigated the effect of globin digest (GD) on the liver injury and hepatic gene expression profile in galactosamine (GalN)-induced liver injury.

MAIN METHODS

The effect of GD on the liver injury was examined by measuring the activities of serum transferases and hepatic antioxidant enzymes, histopathological analysis, gene expression profile, and proteins of the peroxisome proliferator-activated receptor alpha (PPARα) and met proto-oncogene (c-Met) in SD rats at 24 h after GalN administration. The effect of GD on the expression of PPARα and its target gene in AML-12 mouse hepatocytes was also examined.

KEY FINDINGS

GD suppressed the elevated activities of serum transferases in GalN-induced liver injury in SD rats. The thiobarbituric acid reactive substance content in GalN-injured liver was a decreasing tendency by GD. GD suppressed the increased oxidized glutathione content, and increased the decreased protein, reduced glutathione contents, and catalase activity in GalN-injured liver. GD may improve the antioxidant defense system and protein synthesis in GalN-injured liver. GD suppressed the elevated expression of the genes related to the inflammation, and decreased the histopathological grade value of inflammatory cell infiltration in GalN-injured liver. GD increased the expression of PPARα protein in GalN-injured liver, and also increased the expression of PPARα and its target gene in AML-12 hepatocytes. The total and phosphorylated c-Met proteins in GalN-injured liver were the increasing tendencies by GD.

SIGNIFICANCE

These findings indicate that GD has the hepatoprotective effect on GalN-induced liver injury in SD rats.

Protection by dietary Spirulina platensis against D-galactosamine--and acetaminophen-induced liver injuries

Increasing attention has been paid to Spirulina for its potential clinical uses. The present study investigated the protection by dietary Spirulina platensis against d-galactosamine (d-GalN)- and acetaminophen (APAP)-induced hepatitis in ICR mice. Mice in each group (n 6) were fed with a standard diet (American Institute of Nutrition (AIN)-93G), a positive control diet containing 0.5 % butylated hydroxytoluene (BHT), or a diet containing 3, 6 or 9 % S. platensis for 1 week. On the last day the mice were treated with d-GalN (300 mg/kg body weight, intraperitoneally) or APAP (150 mg/kg body weight, intraperitoneally) and 24 h later the mice were killed. The doses of both 6 and 9 % S. platensis were found to significantly alleviate the increase of serum glutamate oxaloacetoacetate transaminase (GOT) and glutamate pyruvate transaminase (GPT) activities in d-GalN- or APAP-intoxicated mice. The observation was very similar to that of the positive control groups. Two more experiments were carried out to investigate the involvement of thiobarbituric acid-reactive substances (TBARS) and IL-18 in the suppression of 6 % S. platensis on d-GalN- and APAP-induced hepatitis. The significant increase of GOT and GPT activities was found to be accompanied with the elevation of hepatic TBARS level, IL-18 mRNA expression and serum IL-18 concentration, and was significantly alleviated by supplementation with 6 % S. platensis in diets. These results showed that dietary S. platensis could provide a significant protection against d-GalN- and APAP-induced liver injuries, and IL-18 and lipid peroxidation might be involved in the protective influence of S. platensis.

The hepatic microcirculation: mechanistic contributions and therapeutic targets in liver injury and repair

The complex functions of the liver in biosynthesis, metabolism, clearance, and host defense are tightly dependent on an adequate microcirculation. To guarantee hepatic homeostasis, this requires not only a sufficient nutritive perfusion and oxygen supply, but also a balanced vasomotor control and an appropriate cell-cell communication. Deteriorations of the hepatic homeostasis, as observed in ischemia/reperfusion, cold preservation and transplantation, septic organ failure, and hepatic resection-induced hyperperfusion, are associated with a high morbidity and mortality. During the last two decades, experimental studies have demonstrated that microcirculatory disorders are determinants for organ failure in these disease states. Disorders include 1) a dysregulation of the vasomotor control with a deterioration of the endothelin-nitric oxide balance, an arterial and sinusoidal constriction, and a shutdown of the microcirculation as well as 2) an overwhelming inflammatory response with microvascular leukocyte accumulation, platelet adherence, and Kupffer cell activation. Within the sequelae of events, proinflammatory mediators, such as reactive oxygen species and tumor necrosis factor-alpha, are the key players, causing the microvascular dysfunction and perfusion failure. This review covers the morphological and functional characterization of the hepatic microcirculation, the mechanistic contributions in surgical disease states, and the therapeutic targets to attenuate tissue injury and organ dysfunction. It also indicates future directions to translate the knowledge achieved from experimental studies into clinical practice. By this, the use of the recently introduced techniques to monitor the hepatic microcirculation in humans, such as near-infrared spectroscopy or orthogonal polarized spectral imaging, may allow an early initiation of treatment, which should benefit the final outcome of these critically ill patients.

Selective blockade of mGlu5 metabotropic glutamate receptors is hepatoprotective against fulminant hepatic failure induced by lipopolysaccharide and D-galactosamine in mice

This study was designed to investigate the influence of 2-methyl-6-phenylethynyl pyridine hydrochloride (MPEP), an antagonist of metabotropic glutamate receptor subtype 5, in lipopolysaccharide (LPS) and d-galactosamine (D-GalN)-induced fulminant hepatic failure in mice. Mice were given an intraperitoneal injection of 50 microg kg(-1) LPS and 500 mg kg(-1) D-GalN. MPEP (1, 5 and 25 mg kg(-1)) was administered intraperitoneally 1 h before LPS/D-GalN injection. Twenty-four hours after administration of LPS/D-GalN, plasma was collected and used for biochemical assays. Mice were euthanized and histological analysis and toxicological parameters were carried out in the liver. MPEP, at all doses tested, protected against the increase in aspartate and alanine aminotransferase activities induced by LPS/D-GalN exposure. Ascorbic acid levels were not altered in all experimental groups. Glutathione S-transferase activity was increased by administration of LPS/D-GalN and MPEP did not modify the enzyme activity in mice. MPEP, at the doses of 5 and 25 mg kg(-1), was effective in protecting against the decrease in catalase activity caused by LPS/D-GalN administration in mice. The histological data showed that sections of liver from LPS/D-GalN-exposed mice presented extensive injuries. MPEP, at all doses tested, reduced the scores of liver damage and markedly ameliorated the degree of liver damage. The hepatoprotective effect of MPEP on fulminant hepatic failure induced by LPS and D-GalN in mice was demonstrated.

Xanthine oxidase-derived reactive oxygen species contribute to the development ofd-galactosamine-induced liver injury in rats

We examined whether xanthine oxidase (XO)-derived reactive oxygen species (ROS) contribute to the development of D-galactosamine (D-GaIN)-induced liver injury in rats. In rats treated with D-GaIN (500 mg/kg), liver injury appeared 6 h after treatment and developed until 24 h. Hepatic XO and myeloperoxidase activities increased 12 and 6 h, respectively, after D-GalN treatment and continued to increase until 24 h. D-GalN-treated rats had increased hepatic lipid peroxide (LPO) content and decreased hepatic reduced glutathione (GSH) and ascorbic acid contents and superoxide dismutase (SOD), catalase and Se-glutathione peroxidase (Se-GSHpx) activities at 24 h, but not 6 h, after treatment. Allopurinol (10, 25 or 50 mg/kg) administered at 6 h after D-GalN treatment attenuated not only the advanced liver injury and increased hepatic XO activity but also all other changes observed at 24 h after the treatment dose-dependently. These results suggest that XO-derived ROS contribute to the development of D-GaIN-induced liver injury in rats.

Role of the perforin/granzyme cell death pathway in D-Gal/LPS-induced inflammatory liver injury

Cytotoxic T lymphocytes and their granule components, such as perforin and granzyme, play an important role in the defense of hepatic infections caused by different pathogens. Moreover, it has been shown in vitro that hepatocytes can initiate cell death via a perforin-dependent mechanism. Although it is well known that hepatocellular apoptosis in D-galactosamine/lipopolysaccharide (D-Gal/LPS)-associated liver failure is mediated by TNF-alpha-dependent Fas/FasL cytotoxicity, there is no information on the role of perforin-mediated mechanisms in vivo. Therefore, we studied whether the cytolytic perforin/granzyme pathway contributes to the D-Gal/LPS-associated hepatotoxicity. Perforin knockout (Pko) mice showed significantly higher hepatic TNF-alpha and IL-6 mRNA expression as well as plasma TNF-alpha and IL-6 concentrations within the first hour upon D-Gal/LPS challenge compared with perforin wild-type (Pwt) mice. At 6 h upon D-Gal/LPS challenge, Pko mice further presented with higher transaminase release and onconecrotic tissue damage, whereas hepatocellular apoptosis and caspase-3 cleavage remained unaffected by the perforin deficiency. Pretreatment with a recombinant human TNF-alpha receptor fusion protein attenuated necrotic and apoptotic tissue damage and reduced plasma transaminase activities as well as cytokine release, thereby preventing acute liver failure in Pko mice as effectively as in Pwt mice. These data do not only confirm the significance of TNF-alpha as distal mediator of hepatic injury in this model but simultaneously reveal a contribution of a perforin-dependent immunoregulation, limiting the D-Gal/LPS-induced overwhelming cytokine release and onconecrotic tissue injury.

Influence of alpha lipoic acid on antioxidant status in D-galactosamine-induced hepatic injury

D-Galactosamine (GalN)-induced liver injury is associated with reactive oxygen species and oxidative stress. In the present study, we evaluated the effect of alpha lipoic acid (ALA) supplementation on acute GalN-induced oxidative liver injury. Hepatotoxicity induced by single intraperitoneal injection of GalN (500 mg/kg body wt) was evident from increase in lipid peroxidation and serum marker enzymes (asparate transaminase, alanine transaminase, alkaline phosphatase, and lactate dehydrogenase). The decreased activities of enzymic antioxidants (superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase) as well as glutathione levels were the salient features observed in GalN-induced hepatotoxicity. Pretreatment with ALA (50 mg/kg body weight for 7 days) significantly precluded these changes and prevents the hepatic injury. Hence, this study clearly exemplified that ALA might be a suitable candidate against GalN-induced cellular abnormalities.

Hepatoprotective effect of 3-alkynyl selenophene on acute liver injury induced by D-galactosamine and lipopolysaccharide

The aim of this study was to investigate the hepatoprotective effect of 3-alkynyl selenophene (compound a), a selenophene compound, on acute liver injury induced by D-galactosamine (D-GalN) and lipopolysaccharide (LPS) in rats. The animals received compound a (25 and 50 mg/kg; per oral, p.o.) in the first day of treatment. In the second day, the rats received D-GalN (500 mg/kg; intraperitoneal, i.p.) and LPS (50 microg/kg; intraperitoneal, i.p.). Twenty-four hours after D-GalN/LPS administration animals were euthanized to the biochemical and histological analysis. Compound a (25 and 50 mg/kg; p.o.) protected against the increase in aspartate aminotransferase (AST) activity induced by D-GalN/LPS. Compound a at 50 mg/kg protected against the increase in alanine aminotransferase (ALT) activity induced by D-GalN/LPS. The inhibition of delta-aminolevulinic dehydratase (delta-ALA-D) activity and the decrease of ascorbic acid levels caused by D-GalN/LPS were protected by compound a (25 and 50 mg/kg). Glutathione S-transferase (GST) and catalase activities were not altered in all groups. The histological data showed that sections of liver from D-GalN/LPS-treated rats presented massive hemorrhage, the presence of inflammatory cells and necrosis. Compound a attenuated D-GalN/LPS-induced hepatic histopathological alterations. Based on the results, we demonstrated the hepatoprotective effect of compound a on acute liver injury induced by D-GalN/LPS.

Aqueous garlic extract attenuates hepatitis and oxidative stress induced by galactosamine/lipoploysaccharide in rats

Injection of D-galactosamine and lipopolysaccharide (DGaIN/LPS) is useful as an experimental model of acute hepatic damage. Juvenile rats were used for investigation. The hepatoprotective activity of aqueous garlic (Allium sativum) extract (AGE) at a dose of 300 mg/kg body weight for 14 days, intraperitoneal (i.p.) prior to the induction of DGalN/LPS, was investigated against DGalN/LPS-induced hepatitis in rats. DGalN/LPS (300 mg/kg body weight/30 microg/kg body weight, i.p.), induced hepatic damage that was manifested by a significant increase in the activities of marker enzymes [alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) and gamma glutamyl transferase (gamma GT)], bilirubin, lipid peroxides (LPO), tumor necrosis factor (TNF-alpha) and myeloperoxidase (MPO) activity level in serum. Also, the lipid profile in serum and liver homogenate including total cholesterol, triglycerides, free fatty acids and phospholipids were significantly deteriorated. The antioxidant enzyme activities (superoxide dismutase, SOD; reduced glutathione, GSH; catalase, CAT and glutathione peroxidase, GPX) in liver homogenate were significantly decreased in the DGalN/LPS. Pretreatment of rats with AGE reversed these altered parameters near to normal control values. Results of this study revealed that AGE could afford a significant protection in the alleviation of DGalN/LPS-induced hepatic damage.

Acute liver cell damage in patients with anorexia nervosa: a possible role of starvation-induced hepatocyte autophagy

BACKGROUND & AIMS

Acute liver insufficiency is a rare complication of anorexia nervosa. The mechanisms for this complication are unclear. The aim of this study was to describe patient characteristics and clarify the mechanisms involved.

METHODS

Liver specimens from 12 patients (median age, 24 years; median body mass index, 11.3 kg/m(2)), with a prothrombin index <50% and/or an International Normalized Ratio >1.7 and anorexia nervosa as the only cause for acute liver injury were analyzed. A detailed pathologic examination was performed, including under electron microscopy.

RESULTS

Liver cell glycogen depletion was a constant finding. There was a contrast between the increase in serum alanine aminotransferase (56 times normal on average; 1,904 IU/L) and the absence of significant hepatocyte necrosis on histology. Centrilobular changes (trabecular atrophy and/or sinusoidal fibrosis) were observed in 6 patients. There were rare or no (<5%) terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling-positive hepatocytes, suggesting that apoptosis was not the primary mechanism. Hepatocytes from 4 patients showed numerous autophagosomes, a morphologic hallmark of autophagy, on electron microscopy. In contrast, the mitochondria, endoplasmic reticulum, and nuclei were normal in most cells. These features were absent in 11 control patients. The outcome was favorable in all patients, with a rapid return to normal liver function.

CONCLUSIONS

Anorexia nervosa with extremely poor nutritional status should be added to the list of conditions causing acute liver insufficiency. Our findings show that starvation-induced autophagy in the human liver may be involved in liver cell death during anorexia nervosa, even though other mechanisms of liver cell damage could also play a role.

Combination of selenium and three naturally occurring antioxidants administration protects D-galactosamine-induced liver injury in rats

D-Galactosamine (D-GaIN) is a highly selective hepatotoxin that causes liver injury similar to human viral hepatitis via depletion of uridine nucleotides, which subsequently diminishes synthesis of RNA and proteins. The aim of this study was to investigate the role of selenium, ascorbic acid, beta-carotene, and alpha-tocopherol on D-GaIN-induced liver injury of rats by morphological and immunohistochemical means. In this study, Sprague-Dawley female rats were divided into four groups. Group I consists of rats injected physiologic saline solution intraperitoneally. Group II consists of rats given selenium (0.2 mg/kg per day), ascorbic acid (100 mg/kg per day), beta-carotene (15 mg/kg per day), and alpha-tocopherol (100 mg/kg per day) for 3 days via gavage method. Group III consists of the single dose of D-GaIN (500 mg/kg)-injected animals. Group IV are the D-GaIN-injected animals given the same antioxidant combination. In situ terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick-end labeling (TUNEL) assay was applied to determine apoptosis for paraffin sections of the liver samples. Moreover, caspase-3 and proliferating cell nuclear antigen antibody were applied for paraffin sections. In the group given D-GaIN, apoptotic cells with TUNEL assays and caspase-3 activity, which are liver injury markers induced by D-GaIN, the hepatocyte proliferation with cell proliferation assay increased. However, selenium and other three antioxidants combination clearly suppressed an increase in apoptotic cells with TUNEL assay and caspase-3 activity. In addition, it suppressed D-GaIN-induced cell proliferation in the liver. As a result, these results indicate that selenium and three naturally occurring antioxidants shows a protective effect against liver injury induced by D-GaIN. These results suggest that supplementation with the combination of selenium, ascorbic acid, beta-carotene, and alpha-tocopherol may help prevent the development of liver injury.

Effects of free radical scavenger on acute liver injury induced by d-galactosamine and lipopolysaccharide in rats

AIM

Acute severe liver injury still has a high mortality rate. Acute liver injury induced by a coadministration of d-galactosamine (GalN) and lipopolysaccharide (LPS) is an experimental model of fulminant hepatitis in rats. Our aim is to investigate the effects of free radical scavenger on the injury induced by GalN/LPS in rats.

METHODS

Free radical scavenger edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one) was twice injected into rats 5 min before and 60 min after the GalN/LPS injection. Liver injury was biochemically and histologically assessed. The survival rate was examined 72 h after the intoxication.

RESULTS

In the GalN/LPS-treated rats, a marked elevation in serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels was observed. On the other hand, edaravone significantly inhibited the elevation in serum AST and ALT levels. The efficacy of edaravone was also confirmedby histological analysis. Edaravone lowered the levels of proinflammatory cytokines TNF-alpha mRNA and interleukin-6 mRNA expression, antioxidative enzyme heme oxygenase-1 protein and myeloperoxidase activity, a marker of neutrophil infiltration, in rat livers. In addition, edaravone reduced the mortality rate in GalN/LPS-treated rats as compared to the rats without edaravone treatment.

CONCLUSIONS

Free radical scavenger edaravone effectively ameliorated the liver injury induced by the GalN/LPS administration in rats, not only by attenuating oxidative stress, but also by reducing the expression of proinflammatory cytokines.

The cytoprotective effect of alpha-tocopherol and daidzein against d-galactosamine-induced oxidative damage in the rat liver

We hypothesized that the hepatotoxicity that develops after the induction of oxidative stress (induced by d-galactosamine [GalN]) can be ameliorated by alpha-tocopherol (ATC) and the soy isoflavone daidzein. To test this, we ranked and assigned male Wistar rats into 6 groups, which involved pretreatment (ATC or daidzein) for 1 hour followed by treatment (GalN) for 23 hours. Histopathologic analysis showed that GalN administration induced marked necrosis (P < .001), steatosis (P < .001), both lobular and portal inflammations (P < .001), overall histopathologic score (P < .001), and activation of caspase-3 in the liver (P < .001). Immunohistochemical staining of malondialdehyde-protein adducts, a measure of oxidative stress, was increased in response to GalN (P < .001). Paradoxically, there were increases in total (P < .05) and cytosolic superoxide dismutase (P < .001) activities after GalN administration, indicative of an up-regulation of antioxidant defenses. The concentration of total protein (P < .001), albumin (P < .01), and globulin fractions (P < .001) in the plasma, as well as the activity of aspartate aminotransferase (P < .001), was significantly perturbed after GalN treatment, reflective of overall acute hepatic injury. Administration of daidzein showed a significant amelioration of the Ga1N-induced increase in malondialdehyde-protein adducts (P < .01) and cytosolic superoxide dismutase activities (P < .01) in the liver. However, all other variables were not significantly altered in response to daidzein. In response to ATC pretreatment, the total histopathologic score (P < .05), degree of necrosis (P < .05), and both lobular (P < .05) and portal (P = .05) inflammations were significantly ameliorated. To conclude, both daidzein and ATC protect the liver against oxidative damage possibly via different pathways.

Effect of dimethyl sulphoxide on oxidative stress, activation of mitogen activated protein kinase and necrosis caused by thioacetamide in the rat liver

Thioacetamide (400 mg/kg body weight, i.p.) was administered to rats. After 12 h the activity of plasma glutamate-oxaloacetate transaminase (GOT) and glutamate-pyruvate transaminase (GPT) was significantly higher than that of the control group, and after 24 h plasma GOT and GPT activities strongly increased. These results indicated that the necrotic process was initiated at about 12 h and developed thereafter. By co-administration of dimethyl sulphoxide (DMSO, 18 and 1 h before, and 8 h after administration of thioacetamide: each time, 2.5 ml/kg body weight, p.o.), plasma GOT and GPT were significantly decreased and were even comparable to the control group, showing that DMSO totally prevented the necrotic action of thioacetamide. After 12 and 24 h of thioacetamide administration, the hepatic level of vitamin C, the most sensitive chemical indicator of oxidative stress, decreased significantly, indicating that oxidative stress was significantly enhanced 12 h after thioacetamide intoxication and thereafter. DMSO totally restored the liver vitamin C level, demonstrating that DMSO effectively ameliorated the oxidative stress caused by thioacetamide, resulting in the prevention of necrosis of the liver. Phosphorylated c-Jun NH(2)-terminal kinase (JNK) significantly increased transiently 12 h after treatment with thioacetamide. These results indicated that oxidative stress and the activation of JNK took place almost simultaneously. Phosphorylated extracellular signal-related kinase (ERK) 2 was significantly increased 6-12 h after thioacetamide injection. Phosphorylated p38 MAPK (mitogen activated protein kinase) was significantly decreased 24 h after administration of thioacetamide. DMSO treatment inhibited the change of these MAPKs by thioacetamide, corresponding with the prevention of the liver necrosis as well as the attenuation of oxidative stress.

The effect of heme oxygenase-1 induction by glutamine on TNBS-induced colitis. The effect of glutamine on TNBS colitis

BACKGROUND

Inflammatory bowel disease is a multifactorial inflammatory disease of the colon and rectum with an unknown etiology. In the present study, we aimed to investigate whether heme oxygenase-1 (HO-1) induction by glutamine could protect colitis-induced damage from oxidative, inflammatory, and apoptotic damage.

METHOD

The rats were divided into four groups. Group 1 had TNBS colitis alone, group 2 had TNBS-induced colitis and glutamine 1 g/kg/day intragastric gavage for 3 days before TNBS solution administration and 15 days following TNBS solution administration, group 3 had glutamine alone 1 g/kg/day intragastric gavage for 18 days before being killed, and group 4 had isotonic saline solution alone 1 cm3/rat intragastric gavage for 18 days before being killed. Colonic malondialdehyde (MDA) levels, glutathione (GSH) levels, caspase-3 activities, and HO-1 expressions of the killed rats were measured. Nuclear factor kappa B (NF-kappaB) and HO-1 expression were evaluated by immunohistochemical examination of the colonic tissue.

RESULT

TNBS-induced colitis significantly increased the colonic MDA levels, caspase-3 activities, and HO-1 expression in comparison to the control group. Glutamine treatment was associated with increased HO-1 expression and GSH levels and decreased MDA levels and caspase-3 activity. Histopathological examination revealed that the intestinal mucosal structure was preserved in the glutamine-treated group. In addition to this, treatment with glutamine significantly increased HO-1 expression and decreased NF-kappaB expression by immunohistochemistry when compared to the TNBS-induced colitis group.

CONCLUSION

Glutamine reduced colonic damage in TNBS-induced colitis. The mechanism of the protection associated with glutamine was due to antioxidant, antiapoptotic, anti-inflammatory, and HO-1 induction effects.