Colchicine protects mice from the lethal effect of an agonistic anti-Fas antibody

The aim of this study was to determine whether colchicine, which has been reported to protect against various hepatotoxic insults, influences the susceptibility of mice to the agonistic anti-Fas antibody, Jo2. All mice that were pretreated with colchicine (2 mg/kg) survived the lethal challenge of intraperitoneal administration of 10 microg of Jo2, whereas all control mice pretreated with gamma-lumicolchicine succumbed to the challenge. Twelve micrograms of Jo2 killed less than half of colchicine-pretreated mice and its lethal effects were delayed relative to control mice, which all died within 8 hours. Other microtubule-disrupting agents such as Taxol, vinblastine, and nocodazole also improved the survival of mice treated with the lethal dose of Jo2. Histologic examination showed that colchicine protected against Jo2-induced fulminant liver injury, and TUNEL assay demonstrated that colchicine protected against massive apoptosis of hepatocytes. Hepatocytes isolated from colchicine-pretreated mice exhibited decreased susceptibility to Jo2-induced apoptosis. In addition, colchicine pretreatment reduced surface expression of Fas and decreased Jo2- and TNF-alpha-induced apoptosis of cultured hepatocytes in the presence of actinomycin D, but did not affect the susceptibility of cultured sinusoidal endothelial cells to Jo2-induced apoptosis. Remarkably, Fas and TNF receptor-1 mRNA and intracellular protein levels increased after colchicine treatment, indicating that colchicine protects against death ligand-induced apoptosis in the liver by decreasing death-receptor targeting to the cell surface.     

Endoplasmic reticulum stress due to altered cellular redox status positively regulates murine hepatic CYP2A5 expression

Murine hepatic cytochrome P450 2A5 (CYP2A5) is uniquely induced by a variety of agents that cause liver injury and inflammation, conditions that are typically associated with downregulation of P450s. We hypothesized that induction of CYP2A5 occurs in response to hepatocellular damage resulting in endoplasmic reticulum (ER) stress. Treatment of mice in vivo and mouse hepatocytes in primary culture with the CYP2A5 inducer pyrazole resulted in overexpression of the ER stress biomarker glucose-regulated protein (GRP) 78. Treatment of primary hepatocytes with ER stress activators thapsigargin, tunicamycin, and trans-4,5-dihydroxy-1,2-dithiane (DTT(ox)) and the calcium ionophore A23187 (calcimycin) resulted in elevated GRP78 mRNA levels; however, only the reducing agent DTT(ox) induced levels of CYP2A5 mRNA, protein, and coumarin 7-hydroxylase activity. To test the hypothesis that CYP2A5 induction is due to liver injury resulting from altered cellular redox status, we demonstrated that CYP2A5 induction, elevated serum alanine aminotransferase, and oxidative protein damage occur concurrently in pyrazole-treated mice. Pyrazole also induced the expression of cytosolic alpha and mu class glutathione S-transferase expression both in vivo and in primary mouse hepatocytes. Moreover, treatment of hepatocytes with the redox cycling quinone menadione resulted in overexpression of CYP2A5 and GSTM1 mRNA. Finally, pretreatment of hepatocytes with the antioxidants N-acetylcysteine and vitamin E attenuated pyrazole-mediated increases in CYP2A5 mRNA levels. These findings clearly indicate that induction of mouse hepatic CYP2A5 during liver injury occurs via a novel mechanism involving ER stress due to altered cellular redox status.     

Irbesartan,an angiotensin II receptor antagonist,with selective PPAR‐gamma‐modulating activity improves function and structure of chemotherapy‐damaged ovaries in rats

Cyclophosphamide (CYP) is a chemotherapeutic agent with a potent ovarian toxic effect. CYP induces granulosa cell apoptosis and oxidative stress. Irbesartan (IRB) is a unique ARB with a peroxisome proliferator‐activated receptor‐gamma (PPAR‐γ) agonistic activity. As PPAR‐? activation exerts anti‐inflammatory effects and reduces ROS production, IRB may further reduce inflammatory chemokine expression and suppress apoptotic cell death. Therefore, this study aimed to evaluate the effects of IRB on the development of CYP‐induced ovarian damage. Rats were divided into four groups: control group, IRB group (100 mg/kg, orally), CYP group (100 mg/kg, i.p. single injection), and IRB+CYP group (IRB administered 9 days before and 6 days after CYP administration). Rats sacrificed on day 16 of experiment; estradiol (E2), FSH, and TNF‐α levels were estimated in serum. Reduced glutathione (GSH), malondialdehyde (MDA), superoxide dismutase (SOD) and caspase‐3 activities, myeloperoxidase (MPO), and IL‐10 levels were determined in ovarian tissues. Protein expressions of p53, caspase‐3, Ki‐67, and Rad‐51 were estimated by immunohistochemical and Western blot techniques. CYP produced ovarian damage as indicated from the decline in serum E2; elevation in FSH; unbalance in tissue oxidative stress parameters; increase in MPO, TNF‐α levels, caspase‐3 activity/expression, p53, and Rad‐51 expression; and decrease in IL‐10 contents, without effect on Ki‐67. On the other hand, IRB, significantly reduced the toxic effects of CYP as indicted from normalization of E2, FSH, oxidative stress, apoptotic, and inflammatory mediators. These data were further supported by histopathological studies. Thus, co‐administration of IRB may be promising in alleviating the ovarian toxic effects of CYP.     

Potentiation of thioacetamide liver injury in diabetic rats is due to induced CYP2E1

Thioacetamide (TA)-induced hepatotoxicity is potentiated in streptozotocin (STZ)-induced diabetic rats. The relative roles of CYP2E1 and FMO1 in the mechanism of TA-associated liver injury were investigated. In the STZ-induced diabetic rat, hepatic CYP2E1 protein concentration and p-nitrophenol hydroxylation were induced 8- and 5.6-fold, respectively. Pretreatment with the CYP2E1 inducer, isoniazid (INH, 250 mg/kg, i.p.) before TA (300 mg/kg, i.p.) administration significantly increased TA-associated liver injury as assessed by plasma alanine aminotransferase (ALT). Hepatic CYP2E1 expression and p-nitrophenol hydroxylation were induced 2.2- and 2. 5-fold in the INH-pretreated rat, respectively. Inhibition of CYP2E1 by diallyl sulfide (DAS, 200 mg/kg, p.o., two doses) before TA administration, decreased plasma ALT activity by 60% in the nondiabetic rat and by 75% in the diabetic rat. Abolition of microsomal p-nitrophenol hydroxylation and CCl(4)-induced liver injury confirmed that hepatic CYP2E1 was highly inhibited by DAS. Hepatic flavin-containing monooxygenase (FMO) form 1 expression and methimazole-dependent oxidation of thiocholine were induced 2.5- and 1.8-fold in the diabetic rat, respectively. Dietary administration of 0.25% indole-3-carbinol (I3C) for 10 days inhibited FMO1 expression and enzyme activity in both nondiabetic and diabetic rats. Paradoxically, TA-induced liver injury was increased in these I3C-pretreated rats. These findings indicate that hepatic CYP2E1 appears to be primarily involved in bioactivation of TA. In the STZ-induced diabetic rat, diabetes-induced CYP2E1 appears to be responsible for the potentiated liver injury; Even though hepatic FMO1 is induced in the diabetic rat, it is unlikely to mediate the potentiated TA hepatotoxicity.     

Increased cytotoxicity of carbon tetrachloride in a human hepatoma cell line overexpressing cytochrome P450 2E1

Cytotoxic free radicals generated during the metabolism of carbon tetrachloride by cytochrome P450 2E1 (CYP2E1) are thought to cause hepatotoxicity. Here, the cytotoxic effects of carbon tetrachloride in a liver cell line expressing CYP2E1 (HLE/2E1) are compared with those in the mother cell line (HLE). The effects of carbon tetrachloride on the gene expression of HSP70, a potential marker of oxidative stress, were also examined. The viability of HLE/2E1 cells after exposure to carbon tetrachloride was significantly decreased compared with that of HLE cells. Northern blot analysis revealed that the HSP70 mRNA level was significantly increased after carbon tetrachloride treatment in both cell lines, while the magnitude of its increase was much greater in HLE/2E1 cells than in HLE cells. These results suggest that the oxidative stress induced by CYP2E1 plays an important role in the increase in cytotoxicity of carbon tetrachloride in CYP2E1-overexpressing cells.     

Protein kinase C signaling as a survival pathway against CYP2E1-derived oxidative stress and toxicity in HepG2 cells

Hepatic induction of CYP2E1 is a major pathway involved in oxidative stress and damage caused by chronic ethanol consumption; CYP2E1 also promotes the activation of a variety of hepatotoxins to reactive intermediates. Phorbol esters activate protein kinase C (PKC), thereby blocking cell differentiation and promoting tumor growth. In this study, we examined the possible role of PKC signaling as a survival pathway against CYP2E1-mediated toxicity using transfected HepG2 hepatoma cells stably overexpressing CYP2E1 (E47 cells). Cells were exposed to arachidonic acid (AA) plus Fe, which has been previously reported to cause a synergistic toxicity in E47 cells by a mechanism dependent on CYP2E1 activity and involving oxidative stress and lipid peroxidation. Phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA), but not the inactive analog 4-alpha-TPA, prevented lipid peroxidation, glutathione depletion, and loss of viability produced by AA + Fe in E47 cells. TPA also protected against the toxicity caused by AA alone, or by iron alone, in the E47 cells. TPA did not lower but instead induced catalytically active CYP2E1 in these cells. The protective effect of TPA on CYP2E1-dependent AA + Fe toxicity seemed to involve a PKC-related survival mechanism, since PKC inhibitors such as Ro 31-8425 (bisindolylmaleimide X hydrochloride) or staurosporine abolished that protection, and activation of PKC by TPA was an early event that occurs prior to the developing toxicity. In conclusion, PKC activation by TPA prevents CYP2E1-derived acute oxidative stress and toxicity in HepG2 cells, and this appears to involve maintenance of the intracellular redox homeostasis via PKC signal transduction.     

Sinusoidal endothelium in mouse liver show rapid and saturable binding of Jo2 anti-Fas antibody.

PURPOSE: To evaluate liver binding of Jo2, a Fas agonist antibody known to induce death in mice. PROCEDURES: Jo2 was labeled with 99mTc and separately conjugated with Cy5.5. Following dosing in normal and Fas deficient mice, the in vivo distribution of 99mTc-Jo2 was imaged. Biodistribution studies were conducted, and liver sections from mice injected with Cy5.5-Jo2 were immunostained with endothelial-specific antibodies and examined by confocal microscopy. RESULTS: 99mTc-Jo2 injected intravenously (i.v.) was rapidly bound in the mouse liver. Fas dependence was confirmed by reduced liver binding in Fas deficient mice. For intraperitoneal (i.p.) dosing, the liver binding was delayed. However, tissue distributions were similar for both routes of injection. 99mTc-Jo2 liver binding was saturated at greater than 10 microg. For Cy5.5-Jo2 doses less than 10 microg, binding within the liver was confirmed to be sinusoidal endothelium. CONCLUSIONS: Rapid binding of Jo2 to liver endothelium is the initial event of Jo2-induced death.     

The participation of 2-butanone in 2-butanol-induced potentiation of carbon tetrachloride hepatotoxicity.

The role of alcohol metabolism in 2-butanol-induced potentiation of carbon tetrachloride (CCl4) hepatotoxicity was studied in rats. Animals were sacrificed at various times after the administration of 2-butanol (2.2 ml/kg p.o.) for the determination of blood 2-butanol and 2-butanone concentrations by gas chromatographic analysis. 2-butanol exhibited an apparent elimination half-life of 2.5 hours. With the decline of 2-butanol concentrations, there was a rise in 2-butanone blood concentrations with 43 mg/100 ml detected at 1 hour and a maximum of 105 mg/100 ml detected 4 hours after the administration of the alcohol. A 16-hour pretreatment with either 2-butanol (2.2 ml/kg p.o.) or 2-butanone (1.87 ml/kg p.o.) markedly enhanced the hepatotoxic response of CCl4 (0.1 ml/kg i.p.) as measured by serum glutamic pyruvic transaminase activity, hepatic glucose-6-phosphatase activity and triglyceride content. The enhanced hepatotoxicity produced by 2-butanol was not significantly different from that produced by 2-butanone. The potentiation of CCl4 hepatotoxicity by both agents was substantiated morphologically. The results indicate that 2-butanone production via the oxidation of 2-butanol appears to contribute to the marked response of 2-butanol.     

Linomide prevents the lethal effect of anti-Fas antibody and reduces Fas-mediated ceramide production in mouse hepatocytes.

Fas is an apoptosis-signaling receptor molecule expressed in vivo on thymocytes, liver, heart, and ovary. In vivo administration of the anti-Fas Jo2 antibody in mice induces severe apoptotic liver damage leading to fulminant hepatitis and death. Linomide, a quinoline 3-carboxamide, inhibits apoptosis of B and T cells induced by various stimuli including viruses, superantigens, and glucocorticoids. Mice treated with linomide survived the lethal effect of anti-Fas antibody, did not accumulate ceramide in hepatocytes, and recovered liver structure and function within 96 h of anti-Fas injection, as confirmed by histology and glutamic oxalacetic transaminase, glutamic pyruvic transaminase, and lactate dehydrogenase levels. Surviving mice showed severe depletion of cortical thymocytes, but medullar thymic cells expressing high CD3 and Fas levels also survived the treatment with anti-Fas in the presence of linomide. Heart, lung, and ovary showed no signs of apoptosis promoted by Fas ligation. These results suggest that linomide prevents cell death triggered by Fas ligation and can be useful for therapeutic intervention in fulminant hepatitis.     

Development of Inflammatory Angiogenesis by Local Stimulation of Fas In Vivo

Fas–Fas ligand interaction is thought to be a crucial mechanism in controlling lymphocyte expansion by inducing lymphocyte apoptosis. However, Fas is also broadly expressed on nonlymphoid cells, where its function in vivo remains to be determined. In this study, we describe the development of inflammatory angiogenesis induced by agonistic anti-Fas mAb Jo2 in a murine model where Matrigel is used as a vehicle for the delivery of mediators. The subcutaneous implants in mice of Matrigel containing mAb Jo2 became rapidly infiltrated by endothelial cells and by scattered monocytes and macrophages. After formation and canalization of new vessels, marked intravascular accumulation and extravasation of neutrophils were observed. Several mast cells were also detected in the inflammatory infiltrate. The phenomenon was dose and time dependent and required the presence of heparin. The dependency on activation of Fas is suggested by the observation that the inflammatory angiogenesis was restricted to the agonistic anti-Fas mAb and it was absent in lpr Fas-mutant mice. Apoptotic cells were not detectable at any time inside the implant or in the surrounding tissue, suggesting that angiogenesis and cell infiltration did not result from recruitment of phagocytes by apoptotic cells but rather by a stimulatory signal through Fas-engagement. These findings suggest a role for Fas–Fas ligand interaction in promoting local angiogenesis and inflammation.     

Mitigation of Pennyroyal Oil Hepatotoxicity in the Mouse

OBJECTIVES: Pennyroyal oil ingestion has been associated with severe hepatotoxicity and death. The primary constituent, R-(+)-pulegone, is metabolized via hepatic cytochrome P450 to toxic intermediates. The purpose of this study was to assess the ability of the specific cytochrome P450 inhibitors disulfiram and cimetidine to mitigate hepatotoxicity in mice exposed to toxic levels of R-(+)-pulegone. METHODS: 20-g female BALB/c mice were pretreated with either 150 mg/kg of cimetidine intraperitoneal (IP), 100 mg/kg of disulfiram IP, or both. After one hour, mice were administered 300 mg/kg of pulegone IP and were killed 24 hours later. Data were analyzed using ANOVA. Post-hoc t-tests used Bonferroni correction. RESULTS: There was a tendency for lower serum glutamate pyruvate transaminase in the disulfiram and cimetidine groups compared with the R-(+)-pulegone group. The differences were significant for both the cimetidine and the combined disulfram and cimetidine groups compared with the R-(+)-pulegone group. Pretreatment with the combination of disulfiram and cimetidine most effectively mitigated R-(+)-pulegone-induced hepatotoxicity. CONCLUSIONS: Within the limitations of a pretreatment animal model, the combination of cimetidine and disulfiram significantly mitigates the effects of pennyroyal toxicity and does so more effectively than either agent alone. These data suggest that R-(+)-pulegone metabolism through CYP1A2 appears to be more important in the development of a hepatotoxic metabolite than does metabolism via CYP2E1.     

Contribution of CYP2E1 and CYP3A to acetaminophen reactive metabolite formation

BACKGROUND: CYP2E1, 1A2, and 3A4 have all been implicated in the formation of N-acetyl-p-benzoquinone imine (NAPQI), the reactive intermediate of acetaminophen (INN, paracetamol), in studies in human liver microsomes and complementary deoxyribonucleic acid-expressed enzymes. However, recent pharmacokinetic evidence in humans has shown that the involvement of CYP1A2 is negligible in vivo. The purpose of this study was to evaluate the respective roles of CYP2E1 and 3A4 in vivo. METHODS: The involvement of CYP2E1 was assessed through pretreatment of adult human volunteers with disulfiram to inhibit the enzyme and the role of CYP3A4 through its induction in a second cohort of adults with rifampin (INN, rifampicin). Each of the respective studies was an open-label, balanced-randomized crossover design. Blood samples were obtained serially for 12 hours and urine was collected for 24 hours after acetaminophen administration. Acetaminophen was assayed in plasma, and acetaminophen and metabolites were assayed in urine. RESULTS: The recovery of the thiol metabolites formed by conjugation of NAPQI with glutathione was decreased by 69%, and the formation clearance of NAPQI was decreased by 74% (both P < .01) by pretreatment with disulfiram. Rifampin pretreatment had no effect on the formation of NAPQI or the recovery of thiol metabolites formed by conjugation of NAPQI with glutathione. CONCLUSIONS: CYP2E1 accounts for the formation of NAPQI in intact humans; the contribution of other isozymes of cytochrome P450 appears to be negligible. Under some conditions, disulfiram may be useful in diminishing the formation of NAPQI after acetaminophen overdose.     

Combined phenotypic assessment of cytochrome p450 1A2, 2C9, 2C19, 2D6, and 3A, N-acetyltransferase-2, and xanthine oxidase activities with the "Cooperstown 5+1 cocktail"

Previously, we have validated a 4-drug phenotyping cocktail, the "Cooperstown cocktail," using caffeine (cytochrome p450 [CYP] 1A2, N-acetyltransferase-2 [NAT2], and xanthine oxidase [XO]), dextromethorphan (CYP2D6), omeprazole (CYP2C19), and intravenous midazolam (hepatic CYP3A). Data suggest that warfarin can be used as a safe and accurate biomarker for CYP2C9, and if warfarin is administered with vitamin K, the pharmacodynamic effect is ablated. Twelve subjects received the Cooperstown cocktail, warfarin plus vitamin K, and both sets of biomarkers (Cooperstown 5+1 cocktail) in a randomized crossover fashion. On the basis of log-transformed data and a paired t test, no significant difference was seen for S-warfarin area under the serum concentration-time curve from time 0 to infinity (P =.09), omeprazole metabolic ratio (P =.374), caffeine metabolic ratio (P =.169 for CYP1A2 activity), midazolam plasma clearance (P =.573), or dextromethorphan metabolic ratio (P =.747) with the Cooperstown cocktail, warfarin plus vitamin K alone, or the Cooperstown 5+1 cocktail. During drug administration, the only side effect was mild and short-lived sedation after intravenous midazolam administration. Phenotypic measurements were in concordance with the subject's CYP2C9, CYP2C19, and CYP2D6 genotypes. The Cooperstown 5+1 cocktail may be used to simultaneously assess the activities of CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP3A, NAT2, and XO.     

Bioactivation of 1,1-dichloroethylene by CYP2E1 and CYP2F2 in murine lung

1,1-Dichloroethylene (DCE) exposure evokes lung toxicity with selective damage to bronchiolar Clara cells. Recent in vitro studies have implicated CYP2E1 and CYP2F2 in the bioactivation of DCE to 2-S-glutathionyl acetate [C], a putative conjugate of DCE epoxide with glutathione. An objective of this study was to test the hypothesis that bioactivation of DCE is catalyzed by both CYP2E1 and CYP2F2 in murine lung. Western blot analysis of lung microsomal proteins from DCE-treated CD-1 mice showed time-dependent loss of immunodetectable CYP2F2 and CYP2E1 protein. Dose-dependent formation of conjugate [C] was observed in the lungs of CD-1 mice treated with DCE (75-225 mg/kg), but it was not detected after pretreatment with 5-phenyl-1-pentyne (5-PIP). Treatment of mice with 5-PIP and also with diallyl sulfone (DASO2) significantly inhibited hydroxylation of p-nitrophenol (PNP) and chlorzoxazone (CHZX). Incubation of recombinant CYP2F3 (a surrogate for CYP2F2) and recombinant CYP2E1 with PNP and CHZX confirmed that they are substrates for both of the recombinant enzymes. Incubation of the recombinant enzymes with DASO2 or 5-PIP significantly inhibited hydroxylation of both PNP and CHZX. Bronchiolar injury was elicited in CD-1 mice treated with DCE (75 mg/kg), but it was abrogated with 5-PIP pretreatment. Bronchiolar toxicity also was manifested in the lungs of CYP2E1-null and wild-type mice treated with DCE (75 mg/kg), but protection ensued after pretreatment with 5-PIP or DASO2. These results showed that bioactivation of DCE in murine lung occurred via the catalytic activities of both CYP2E1 and CYP2F2 and that bioactivation by these enzymes mediated the lung toxicity.     

Effect of berberine on hepatocyte proliferation,inducible nitric oxide synthase expression,cytochrome P450 2E1 and 1A2 activities in diethylnitrosamine- and phenobarbital-treated rats

This study investigated the effect of berberine on the early phase of hepatocarcinogenesis stimulated by diethylnitrosamine (DEN, 150 mg/kg, 4 weeks) plus phenobarbital (PB, 75 mg/kg, 7 days) in rats. The expressions of proliferating cell nuclear antigen (PCNA) and inducible nitric oxide synthase (iNOS) were evaluated by immunohistochemistry. The activities of CYP isoenzymes were analyzed using different probe drugs including chlorzoxazone (CYP2E1) and phenacetin (CYP1A2) by high-performance liquid chromatography (HPLC) in vivo or in vitro. Results showed that the expressions of PCNA and iNOS were induced by DEN plus PB in liver tissues. Oral administration of berberine (50 mg/kg) inhibited the hepatocyte proliferation and iNOS expression, decreased cytochrome P450 content, inhibited activities of CYP2E1 and CYP1A2 in DEN-plus-PB-treated rats in vivo. Moreover, berberine (10, 50 and 100 μM) inhibited the activities of CYP2E1 and CYP1A2 in microsomes isolated from DEN-plus-PB-treated rats in vitro, suggesting that anti-hepatocarcinogenetic potential of berberine might be due to inhibiting oxidative metabolic activities of CYP 2E1 and CYP1A2, and decreasing NO production in rats.     

CYP2E1 and CYP4A as microsomal catalysts of lipid peroxides in murine nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH) and alcoholic liver disease have similar pathological features. Because CYP2E1 plays a key role in alcoholic liver disease with its ability to stimulate lipid peroxidation, we tested the proposal that CYP2E1 could also be a factor in the development of NASH. In a dietary model - mice fed a methionine- and choline-deficient (MCD) diet - liver injury was associated with both induction of CYP2E1 and a 100-fold increase in hepatic content of lipid peroxides. Microsomal NADPH-dependent lipid oxidases contributed to the formation of these lipid peroxides, and in vitro inhibition studies demonstrated that CYP2E1 was the major catalyst. To further define the role of CYP2E1 as an initiator of oxidative stress in NASH, Cyp2e1(-/-)mice were administered the MCD diet. CYP2E1 deficiency neither prevented the development of NASH nor abrogated the increased microsomal NADPH-dependent lipid peroxidation, indicating the operation of a non-CYP2E1 peroxidase pathway. In Cyp2e1(-/-) mice with NASH (but not in wild-type mice), CYP4A10 and CYP4A14 were upregulated. Furthermore, hepatic microsomal lipid peroxidation was substantially inhibited by anti-mouse CYP4A10 antibody in vitro. These results show that experimental NASH is strongly associated with hepatic microsomal lipid peroxidation. CYP2E1, the main enzyme associated with that process in wild-type mice, is not unique among P450 proteins in catalyzing peroxidation of endogenous lipids. We have now identified CYP4A enzymes as alternative initiators of oxidative stress in the liver.     

Selective neutralization of prostaglandin E2 blocks inflammation, hyperalgesia, and interleukin 6 production in vivo

The role of prostaglandin E2 (PGE2) in the development of inflammatory symptoms and cytokine production was evaluated in vivo using a neutralizing anti-PGE2 monoclonal antibody 2B5. In carrageenan-induced paw inflammation, pretreatment of rats with 2B5 substantially prevented the development of tissue edema and hyperalgesia in affected paws. The antibody was shown to bind the majority of PGE2 produced at the inflammatory site. In adjuvant-induced arthritis, the therapeutic administration of 2B5 to arthritic rats substantially reversed edema in affected paws. Anti-PGE2 treatment also reduced paw levels of IL-6 RNA and serum IL-6 protein without modifying tumor necrosis factor RNA levels in the same tissue. In each model, the antiinflammatory efficacy of 2B5 was indistinguishable from that of the nonsteroidal antiinflammatory drug indomethacin, which blocked the production of all PGs. These results indicate that PGE2 plays a major role in tissue edema, hyperalgesia, and IL-6 production at sites of inflammation, and they suggest that selective pharmacologic modulation of PGE2 synthesis or activity may provide a useful means of mitigating the symptoms of inflammatory disease.     

Patchouli oil isolated from the leaves of Pogostemon cablin ameliorates ethanol-induced acute liver injury in rats via inhibition of oxidative stress and lipid accumulation

Excessive alcohol consumption can cause serious hepatic injury which is associated with oxidative stress and fatty metabolic disturbance. Patchouli oil (PO) is a sort of food supplement with high medicinal value in hepatoprotection, but its ability against ethanol-induced liver failure has not been demonstrated. Thus, this study aimed to investigate the potential hepatoprotection of PO through an ethanol-induced hepatotoxicity rat model. Our results showed that PO pretreatment could dramatically decrease the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) in serum, paralleled by an improvement of histopathology alterations. Additionally, PO could markedly suppress the content of reactive oxygen species (ROS), tumor necrosis factor alpha (TNF-α), free fatty acid (FFA), and triglyceride (TG), while enhancing the activities of glutathione (GSH), glutathione reductase (GR), and superoxide dismutase (SOD) as well as the ratio of glutathione to oxidized glutathione (GSH/GSSG) in liver. The protective effect of PO against oxidative stress was interrelated with restraining the mRNA and protein expression of hepatic microsomal enzyme cytochrome P450 2E1 (CYP2E1). What''s more, PO pretreatment could also accelerate lipometabolism via up-regulating expressions of adenosine monophosphate-activated protein kinase (AMPK), peroxisome proliferator-activated receptor α (PPAR-α), and carnitine palmitoyltransferase 1 (CPT-1) and down-regulating expressions of nuclear factor-kappaB (NF-κB) p65, sterol regulatory element-binding protein 1 (SREBP-1c), fatty acid synthase (FAS), and stearoyl-CoA desaturase 1 (SCD-1). To conclude, PO showed potent effect against ethanol-induced hepatotoxicity by relieving oxidative stress and preventing lipid accumulation.

Excessive alcohol consumption can cause serious hepatic injury which is associated with oxidative stress and fatty metabolic disturbance.     

Protective effect of Sesbania grandiflora against erythromycin estolate-induced hepatotoxicity

Sesbania grandiflora, commonly known as 'sesbania', is widely used in Indian folk medicine for the treatment of liver disorders. Oral administration of an ethanolic extract of S. grandiflora leaves (200 mg/kg/day) for 15 days produced significant hepatoprotection against erythromycin estolate (800 mg/kg/day)-induced hepatotoxicity in rats. The increased level of serum enzymes (aspartate transaminase, alanine transaminase, alkaline phosphatase), bilirubin, cholesterol, triglycerides, phospholipids, free fatty acids, plasma thiobarbituric acid reactive substances and hydroperoxides observed in rats treated with erythromycin estolate were significantly decreased in rats treated concomitantly with sesbania extract and erythromycin estolate. The sesbania extract also restored the depressed levels of antioxidants to near normal. The results of the study reveal that sesbania could afford a significant protective effect against erythromycin estolate-induced hepatotoxicity. The effect of sesbania was compared with that of silymarin, a reference hepatoprotective drug.