Evaluation of hepatoprotective efficacy of Majoon‐e‐Dabeed‐ul‐ward against acetaminophen‐induced liver damage: A Unani herbal formulation

A Unani herbal formulation known as Majoon‐e‐Dabeed‐ul‐ward (MD) was evaluated for hepatoprotective effect against acetaminophen (APAP; 2 g/kg p.o.)‐induced liver damage. The latter was evidenced by elevated levels of aspartate transaminase (AST), alanine transaminase (ALT), serum alkaline transaminase (SALP), lactate dehydrogenase (LDH), bilirubin, albumin, urea, and creatinine in experimental animals. Increased levels of lipid peroxidation were associated with a concomitant decline in reduced glutathione levels, adenosine triphosphatase (ATPase), and glucose‐6‐phosphatase (G‐6‐Pase) caused by APAP treatment. Treatment with MD (250,500, and 1,000 mg/kg p.o.) reverse the altered levels of AST, ALT, SALP, LDH, bilirubin, albumin, urea, and creatinine in a dose‐dependent manner. Significant restoration was found in LPO, GSH content and metabolic enzymes (ATPase and G‐6‐pase) were seen after therapy. The herbal formulation, MD showed hepatoprotective efficacy against APAP‐induced liver damage. Drug Dev Res 72: 346–352, 2011. © 2010 Wiley‐Liss, Inc.     

Hepatoprotective effects of DL-α-lipoic acid and α-Tocopherol through amelioration of the mitochondrial oxidative stress in acetaminophen challenged rats

Abstract

Acetaminophen (APAP) is known to induce liver mitochondrial dysfunction leading to acute hepatotoxicity. Effect of DL-α-lipoic acid (LA) and α-tocopherol (α-Toc) against the APAP-induced liver mitochondrial damage was evaluated in rats. LA (100?mg/kg, p.o.) and α-Toc (100?mg/kg, p.o.) were given once daily for 15?d, prior to the APAP administration (3?g/kg, p.o). Hepatic damage was confirmed by determining the activities of serum glutamate pyruvate transaminase, serum glutamate oxaloacetate transaminase and alkaline phosphatase, 4?h after the single dose of APAP. To assess the mitochondrial damage, the activities of antioxidant enzymes, Krebs’ cycle dehydrogenases and mitochondrial electron transport chain complexes, and levels of reactive oxygen species (ROS), reduced glutathione, lipid peroxidation (malondialdehyde, MDA) as well as the mitochondrial membrane potential (Δψmt) were evaluated. The activities of mitochondrial enzymes and Δψmt were significantly (p?<?0.01) decreased and the level of ROS and MDA were significantly (p?<?0.01) increased due to APAP challenge. LA and α-Toc treatment significantly enhanced the activities of mitochondrial enzymes and Δψmt than that of control group; whereas the levels of ROS and MDA were decreased. The results of the study concluded that the liver damage induced by APAP was significantly ameliorated by LA and α-Toc. LA showed more protection than that of α-Toc. The protection can be partially ascribed to their mitochondrial protective effects through their antioxidant activity which could decrease the level of ROS and by direct enhancement of Δψmt.     

Silymarin protects against paracetamol-induced lipid peroxidation and liver damage.

The effect of silymarin on liver damage induced by acetaminophen (APAP) intoxication was studied. Wistar male rats pretreated (72 h) with 3-methylcholanthrene (3-MC) (20 mg kg-1 body wt. i.p.) were divided into three groups: animals in group 1 were treated with acetaminophen (APAP) (500 mg kg-1 body wt. p.o.), group 2 consisted of animals that received APAP plus silymarin (200 mg kg-1 body wt. p.o.) 24 h before APAP, and rats in group 3 (control) received the equivalent amount of the vehicles. Animals were sacrificed at different times after APAP administration. Reduced glutathione (GSH), lipid peroxidation and glycogen were measured in liver and alkaline phosphatase (AP), gamma-glutamyl transpeptidase (GGTP) and glutamic pyruvic transaminase (GPT) activities were measured in serum. After APAP intoxication, GSH and glycogen decreased very fast (1 h) and remained low for 6 h. Lipid peroxidation increased three times over the control 4 and 6 h after APAP treatment. Enzyme activities increased 18 h after intoxication. In the group receiving APAP plus silymarin, levels of lipid peroxidation and serum enzyme activities remained within the control values at any time studied. The fall in GSH was not prevented by silymarin, but glycogen was restored at 18 h. It was concluded that silymarin can protect against APAP intoxication through its antioxidant properties, possibly acting as a free-radical scavenger.     

Moringa oleifera Lam prevents acetaminophen induced liver injury through restoration of glutathione level

Initiation of acetaminophen (APAP) toxicities is believed to be promoted by oxidative stress during the event of overdosage. The aim of the present study was to evaluate the hepatoprotective action of Moringa oleifera Lam (MO), an Asian plant of high medicinal value, against a single high dose of APAP. Groups of five male Sprague-Dawley rats were pre-administered with MO (200 and 800 mg/kg) prior to a single dose of APAP (3g/kg body weight; p.o). Silymarin was used as an established hepatoprotective drug against APAP induced liver injury. The hepatoprotective activity of MO extract was observed following significant histopathological analysis and reduction of the level of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and alkaline phosphatase (ALP) in groups pretreated with MO compared to those treated with APAP alone. Meanwhile, the level of glutathione (GSH) was found to be restored in MO-treated animals compared to the groups treated with APAP alone. These observations were comparable to the group pretreated with silymarin prior to APAP administration. Group that was treated with APAP alone exhibited high level of transaminases and ALP activities besides reduction in the GSH level. The histological hepatocellular deterioration was also evidenced. The results from the present study suggested that the leaves of MO can prevent hepatic injuries from APAP induced through preventing the decline of glutathione level.     

Artemisia pallens alleviates acetaminophen induced toxicity via modulation of endogenous biomarkers

Abstract

Context: Acetaminophen (APAP) leads to severe hepatic and renal necrosis and thus causes significant clinical problems. Artemisia pallens Walls ex D.C. (Asteraceae) possesses various pharmacological properties such as antidiabetic, antioxidant, analgesic, and anti-inflammatory activity.

Objective: The objective was to evaluate the protective effects of Artemisia pallens methanol extract (APME) in APAP-induced hepatic and nephro-toxicity.

Materials and methods: The methanolic extract of aerial parts of Artemisia pallens (APME) was prepared. Toxicity was induced in male Wistar rats (180–220?g) by administration of APAP (700?mg/kg, p.o., 14?d). APME (100, 200, and 400?mg/kg, p.o.) was administered to rats 2?h before APAP oral administration. Various biochemical and molecular parameters along with histopathological aberration were studied in the kidney and liver of rats.

Results: Pretreatment with APME (200 and 400?mg/kg, p.o.) significantly (p?<?0.01 and p?<?0.001) decreased aspartate transaminase (AST), alanine transaminase (ALT), bilirubin, blood urea nitrogen (BUN), and serum creatinine as compared with APAP-treated rat. Decreased level of serum albumin, serum uric acid, and HDL were significantly (p?<?0.01 and p?<?0.001) restored by APME (200 and 400?mg/kg, p.o.) pre-treatment. Administration of APME (200 and 400?mg/kg, p.o.) significantly (p?<?0.01 and p?<?0.001) reduced the elevated level of cholesterol, LDL, LDH, triglyceride, and VLDL. It also significantly (p?<?0.01 and p?<?0.001) restored the altered level of hepatic and renal antioxidant enzymes (superoxide dismutase (SOD) and glutathione (GSH)). The increased level of malondialdehyde (MDA) and nitric oxide (NO) in hepatic as well as renal tissue was significantly (p?<?0.01 and p?<?0.001) decreased by APME (200 and 400?mg/kg, p.o.) administration. Histological alternation induced by APAP in liver and kidney was also reduced by the APME (200 and 400?mg/kg, p.o.) pre-treatment.

Conclusion: It is concluded that the methanol extract of Artemisia pallens alleviates APAP induced in rats toxicity through its antioxidative and anti-inflammatory actions.     

Reversal of acetaminophen induced subchronic hepatorenal injury by propolis extract in rats

The ethanolic extract of propolis (200mg/kg, p.o.) was evaluated against acetaminophen (APAP; 20mg/kg, p.o.) induced subchronic hepatorenal injury in rats. Administration of APAP significantly increased the release of serum transaminases, alkaline phosphatase, lactate dehydrogenase, γ-glutamyl transpeptidase, bilirubin and serum proteins, whereas concomitantly decreased hemoglobin, blood sugar and albumin. Hepatorenal reduced glutathione and activities of superoxide dismutase and catalase, hepatic CYPs i.e., aniline hydroxylase and amidopyrine-N-demethylase were significantly decreased after APAP intoxication. Lipid peroxidation showed significant elevation in both organs significantly after APAP assault. Total proteins, glycogen contents and the activities of certain metabolic enzymes i.e., adenosine triphosphatase, alkaline phosphatase and acid phosphatase were altered after APAP administration. Propolis extract exhibited curative effects by reversing APAP induced alterations in blood biochemical variables, CYP enzymes and markers of oxidative stress. Histopathological analysis of liver and kidney was consistent with the biochemical findings and led us to conclude the curative potential of propolis against APAP induced hepatorenal injury.     

Comparison of S-adenosyl-L-methionine (SAMe) and N-acetylcysteine (NAC) protective effects on hepatic damage when administered after acetaminophen overdose

In the clinical setting, antidotes are generally administered after the occurrence of a drug overdose. Therefore, the most pertinent evaluation of any new agent should model human exposure. This study tested whether acetaminophen (APAP) hepatotoxicity was reversed when S-adenosyl-L-methionine (SAMe) was administered after APAP exposure, similar to what occurs in clinical situations. Comparisons were made for potency between SAMe and N-acetylcysteine (NAC), the current treatment for APAP toxicity. Male C57BL/6 mice were fasted overnight and divided into groups: control (VEH), SAMe treated (SAMe), APAP treated (APAP), N-acetylcysteine treated (NAC), SAMe or NAC administered 1h after APAP (SAMe+APAP) and (NAC+APAP), respectively. Mice were injected intraperitoneal (i.p.) with water (VEH) or 250 mg/kg APAP (15 ml/kg). One hour later, mice were injected (i.p.) with 1.25 mmol/kg SAMe (SAMe+APAP) or NAC (NAC+APAP). Hepatotoxicity was evaluated 4h after APAP or VEH treatment. APAP induced centrilobular necrosis, increased liver weight and alanine transaminase (ALT) levels, depressed total hepatic glutathione (GSH), increased protein carbonyls and 4-hydroxynonenal (4-HNE) adducted proteins. Treatment with SAMe 1h after APAP overdose (SAMe+APAP) was hepatoprotective and was comparable to NAC+APAP. Treatment with SAMe or NAC 1h after APAP was sufficient to return total hepatic glutathione (GSH) to levels comparable to the VEH group. Western blot showed reversal of APAP mediated effects in the SAMe+APAP and NAC+APAP groups. In summary, SAMe was protective when given 1h after APAP and was comparable to NAC.     

Propolis reverses acetaminophen induced acute hepatorenal alterations: A biochemical and histopathological approach

The present study has been conducted to evaluate the curative effect of propolis extract, a honey bee-hive product, against acetaminophen (APAP) induced oxidative stress and dysfunction in liver and kidney. Animals were challenged with APAP (2 g/kg, p.o.) followed by treatment of propolis extract (100 and 200 mg/kg, p.o.) once only after 24 h. Release of transaminases, alkaline phosphatase, lactate dehydrogenase, and serum bilirubin were increased, whereas hemoglobin and blood sugar were decreased after APAP administration. Antioxidant status in both the liver and kidney tissues were estimated by determining the glutathione, malondialdehyde content and activities of the CYP enzymes, which showed significant alterations after APAP intoxication. In addition, activities of adenosine triphosphatase, acid phosphatase, alkaline phosphatase, and major cell contents (total protein, glycogen and cholesterol) were also altered due to APAP poisoning. Propolis extract successfully reversed the alterations of these biochemical variables at higher dose. Improvements in hepatorenal histoarchitecture were also consistent with biochemical observations. The results indicated that ethanolic extract of propolis has ability to reverse APAP-induced hepatorenal biochemical and histopathological alterations probably by increasing the antioxidative defense activities due to various phenolic compounds present in it.     

Astaxanthin pretreatment attenuates acetaminophen-induced liver injury in mice

BackgroundAcetaminophen (APAP) is a conventional drug widely used in the clinic because of its antipyretic-analgesic effects. However, accidental or intentional APAP overdoses induce liver injury and even acute liver failure (ALF). Astaxanthin (ASX) is the strongest antioxidant in nature that shows preventive and therapeutic properties, such as ocular protection, anti-tumor, anti-diabetes, anti-inflammatory, and immunomodulatory effects. The aim of present study was to determine whether ASX pretreatment provides protection against APAP-induced liver failure.MethodsMale C57BL/6 mice were randomly divided into 7 groups, including control, oil, ASX (30 mg/kg or 60 mg/kg), APAP and APAP + ASX (30 mg/kg or 60 mg/kg) groups. Saline, olive oil and ASX were administered for 14 days. The APAP and APAP + ASX groups were given a peritoneal injection of 700 mg/kg or 300 mg/kg APAP to determine the 5-day survival rate and for further observation, respectively. Blood and liver samples were collected to detect alanine transaminase (ALT), aspartate transaminase (AST), inflammation, oxidative stress and antioxidant systems, and to observe histopathologic changes and key proteins in the mitogen-activated protein kinase (MAPK) family.ResultsASX pretreatment before APAP increased the 5-day survival rate in a dose-dependent manner and reduced the ALT, AST, hepatic necrosis, reactive oxygen species (ROS) generation, lipid peroxidation (LPO), oxidative stress and pro-inflammatory factors. ASX protected against APAP toxicity by inhibiting the depletion of glutathione (GSH) and superoxide dismutase (SOD). Administration of ASX did not change the expression of c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK) and P38. However, phosphorylation of JNK, ERK and P38 was reduced, consistent with the level of tumor necrosis factor alpha (TNF-α) and TNF receptor-associated factor 2 (TRAF2).ConclusionASX provided protection for the liver against APAP hepatotoxicity by alleviating hepatocyte necrosis, blocking ROS generation, inhibiting oxidative stress, and reducing apoptosis by inhibiting the TNF-α-mediated JNK signal pathway and by phosphorylation of ERK and P38, which made sense in preventing and treating liver damage.     

Restoration of histoarchitecture in the paracetamol-induced liver damaged rat by earthworm extract, Lampito mauritii (Kinberg)

Lampito mauritii, an earthworm widely used in Siddha as well as Ayurveda, has been reported to have anti-inflammatory, anti-ulceral and anti-oxidative properties. The present investigation shows its hepatoprotective role. Whole tissue extract of Lampito mauritii protect the paracetamol (2 g/kg body weight. p.o.) induced liver damage rat as a dose dependent manner (100, 200 and 300 mg/kg body weight p.o.) by significantly (P < 0.05) decreasing the hepatic marker enzymes--aspartate transaminase, alanine transaminase and alkaline phosphatase similar to silymarin (150 mg/kg b.w. p.o.). Histopathological observations of liver tissues corroborated these findings.     

Hepatoprotective activity of methanolic extract of Hiptage bengalensis leaves against CCl₄-induced hepatotoxicity in rats

The objective of the present study was to evaluate hepatoprotective activity of methanolic extract of Hiptage bengalensis (L.) kurz (MEHB) in rats. Hepatic damage was induced by administration of carbontetrachloride(1 ml/kg, b.w, p.o.) in combination with liquid paraffin (1:1) as a single dose on 7th day. The extent of liver damage was studied by estimating biochemical parameters. Administration of MEHB (200 mg & 400 mg/kg) for 6 days before carbontetrachloride administration showed a significant reduction (p < 0.01) of serum liver damage enzymes markers-aspartate transaminase, alanine transaminase, total bilirubin and alkaline phosphatase (ALP). Histopathological changes of hepatic tissue were also evaluated in control and MEHB treated groups. Results also indicated that MEHB possessed potential antioxidant effect by increasing the levels of glutathione and also possessed free radical scavenging activities. The hepatoprotective effect of Hiptage bengalensis (L.) kurz was comparable to standard drug silymarin (50 mg/kg).     

Effect of repeated administration with subtoxic doses of acetaminophen to rats on enterohepatic recirculation of a subsequent toxic dose

Development of resistance to toxic effects of acetaminophen (APAP) was reported in rodents and humans, though the mechanism is only partially understood. We examined in rats the effect of administration with subtoxic daily doses (0.2, 0.3, and 0.6 g/kg, i.p.) of APAP on enterohepatic recirculation and liver toxicity of a subsequent i.p. toxic dose of 1 g/kg, given 24 h after APAP pre-treatment. APAP and its major metabolite APAP-glucuronide (APAP-Glu) were determined in bile, urine, serum and liver homogenate. APAP pre-treatment was not toxic, as determined by serum markers of liver damage and neither induced oxidative stress as demonstrated by assessment of ROS generation in liver or glutathione species in liver and bile. APAP pre-treatment induced a partial shift from biliary to urinary elimination of APAP-Glu after administration with the toxic dose, and decreased hepatic content and increased serum content of this conjugate, consistent with a marked up-regulation of its basolateral transporter Mrp3 relative to apical Mrp2. Preferential secretion of APAP-glu into blood decreased enterohepatic recirculation of APAP, thus attenuating liver exposition to the intact drug, as demonstrated 6 h after administration with the toxic dose. The beneficial effect of interfering the enterohepatic recirculation was alternatively tested in animals receiving activated charcoal by gavage to adsorb APAP of biliary origin. The data indicated decreased liver APAP content and glutathione consumption. We conclude that selective up-regulation of Mrp3 expression by APAP pre-treatment may contribute to development of resistance to APAP hepatotoxicity, at least in part by decreasing its enterohepatic recirculation.     

Antifibrotic effect of extracellular biopolymer from submerged mycelial cultures of Cordyceps militaris on liver fibrosis induced by bile duct ligation and scission in rats

The antifibrotic effects of hot water extract (WEC), intracellular biopolymer (IPC) and extracellular biopolymers (EPC) from mycelial liquid culture of Cordyceps militaris on liver fibrosis were studied. Liver fibrosis was induced by a bile duct ligation and scission (BDL/S) operation, duration of 4 weeks in rats. In BDL/S rats, the levels of aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), total bilirubin in serum and hydroxyproline content in liver were dramatically increased. The WEC or IPC treatment (30 mg/kg/day for 4 weeks, p.o.) in BDL/S rats reduced the serum AST, ALT and ALP levels significantly (p<0.01). The EPC treatment (30 mg/kg/day for 4 weeks, p.o.) reduced the serum ALT, AST and ALP levels significantly (p<0.01). Malondialdehyde contents in liver treated with WEC, IPC or EPC were significantly reduced (p<0.05). But Liver hydroxyproline content was decreased only in EPC treated BDL/S rats to 55% that of BDL/S control rats (p<0.01). The morphological characteristics and expression of alpha smooth muscle like actin in fibrotic liver, which appeared in BDL/S control group were improved in EPC treated fibrotic liver. These results indicate that EPC (30 mg/kg/day for 4 weeks, p.o.) has an antifibrotic effect on fibrotic rats induced by BDL/S.     

Hepatoprotective activity of methanolic extract of Hiptage bengalensis leaves against CCl4-induced hepatotoxicity in rats

The objective of the present study was to evaluate hepatoprotective activity of methanolic extract of Hiptage bengalensis (L.) kurz (MEHB) in rats. Hepatic damage was induced by administration of carbontetrachloride(1 ml/kg, b.w, p.o.) in combination with liquid paraffin (1:1) as a single dose on 7th day. The extent of liver damage was studied by estimating biochemical parameters. Administration of MEHB (200 mg & 400 mg/kg) for 6 days before carbontetrachloride administration showed a significant reduction (p < 0.01) of serum liver damage enzymes markers-aspartate transaminase, alanine transaminase, total bilirubin and alkaline phosphatase (ALP). Histopathological changes of hepatic tissue were also evaluated in control and MEHB treated groups. Results also indicated that MEHB possessed potential antioxidant effect by increasing the levels of glutathione and also possessed free radical scavenging activities. The hepatoprotective effect of Hiptage bengalensis (L.) kurz was comparable to standard drug silymarin (50 mg/kg).     

Hepatoprotective effect of Himoliv, a polyherbal formulation in rats

The effect of Himoliv (HV) was evaluated in carbon tetrachloride or paracetamol induced hepatotoxicity in rats. Liver necrosis was produced by administering single dose of either carbon tetrachloride (CCl4, 1 ml/kg, 50% v/v with olive oil, s.c.) or paracetamol (PC, 1 g/kg, p.o.). The liver damage was evidenced by elevated levels of serum glutamate oxaloacetate transaminase (SGOT), serum glutamate pyruvate transaminase (SGPT) and serum alkaline phosphatase (ALP) and hepatic thiobarbituric acid reacting substances (TBARS) and superoxide dismutase (SOD). HV pretreatment (0.5 and 1.0 ml/kg, p.o.) significantly (P < 0.001) reduced CCl4 or PC-induced elevations of the levels of SGOT, SGPT, ALP and TBARS, while the reduced concentration of SOD due to CCl4 or PC was reversed. Silymarin (25 mg/ kg, p.o.), a known hepatoprotective drug showed similar results.     

Temporal study of acetaminophen (APAP) and S-adenosyl-l-methionine (SAMe) effects on subcellular hepatic SAMe levels and methionine adenosyltransferase (MAT) expression and activity

Acetaminophen (APAP) is the leading cause of drug induced liver failure in the United States. Previous studies in our laboratory have shown that S-adenosyl methionine (SAMe) is protective for APAP hepatic toxicity. SAMe is critical for glutathione synthesis and transmethylation of nucleic acids, proteins and phospholipids which would facilitate recovery from APAP toxicity. SAMe is synthesized in cells through the action of methionine adenosyltransferase (MAT). This study tested the hypothesis that total hepatic and subcellular SAMe levels are decreased by APAP toxicity. Studies further examined MAT expression and activity in response to APAP toxicity. Male C57BL/6 mice (16-22 g) were treated with vehicle (Veh; water 15 ml/kg ip injections), 250 mg/kg APAP (15 ml/kg, ip), SAMe (1.25 mmol/kg) or SAMe administered 1 h after APAP injection (SAMe and SAMe + APAP). Hepatic tissue was collected 2, 4, and 6 h after APAP administration. Levels of SAMe and its metabolite S-adenosylhomocysteine (SAH) were determined by HPLC analysis. MAT expression was examined by Western blot. MAT activity was determined by fluorescence assay. Total liver SAMe levels were depressed at 4 h by APAP overdose, but not at 2 or 6 h. APAP depressed mitochondrial SAMe levels at 4 and 6 h relative to the Veh group. In the nucleus, levels of SAMe were depressed below detectable limits 4 h following APAP administration. SAMe administration following APAP (SAMe + APAP) prevented APAP associated decline in mitochondrial and nuclear SAMe levels. In conclusion, the maintenance of SAMe may provide benefit in preventing damage associated with APAP toxicity.     

Anti-fibrotic effects of a hot-water extract from Salvia miltiorrhiza roots on liver fibrosis induced by biliary obstruction in rats

The anti-fibrotic effects of a hot-water extract form the traditional Chinese medicinal herb Salvia miltiorrhiza (Labiatae) on liver fibrosis induced by biliary obstruction was studied in rats. Liver fibrosis was induced in male Sprague-Dawley rats by bile duct ligation and scission (BDL). After surgery, the hot-water extract of S. miltiorrhiza roots (100 mg kg(-1), p.o.) was administered daily for 28 days. The concentrations of aspartate transaminase, alanine transaminase, alkaline phosphatase, total bilirubin and total cholesterol in serum and hydroxyproline and malondialdehyde contents in liver were significantly increased in BDL rats. Treatment with the extract of S. miltiorrhiza significantly reduced (P < 0.01) the serum aspartate transaminase, alanine transaminase, alkaline phosphatase, and total cholesterol concentrations in BDL rats. The liver hydroxyproline content in BDL rats treated with extract was also reduced to 68% of that in BDL control rats (P < 0.01). The liver malondialdehyde content in BDL rats treated with the extract was also reduced to 47% of that in BDL control rats (P < 0.01). The morphological characteristics of fibrotic livers were improved in BDL rats treated with extract. Immunohistochemical examination of fibrotic liver showed that the extract of S. miltiorrhiza markedly reduced protein expression of alpha-smooth muscle cell-like actin, which indicates that hepatic stellate cell activation was inhibited during liver fibrosis development. The results indicate that the hot-water extract of S. miltiorrhiza roots inhibits fibrosis and lipid peroxidation in rats with liver fibrosis induced by biliary obstruction.     

CYP2E1 and miRNA‐378a‐3p contribute to acetaminophen‐ or tripterygium glycosides‐induced hepatotoxicity

Increased expression of CYP2E1 may represent the main factor contributing to oxidative stress‐mediated liver damage in drug‐induced liver injury (DILI). However, the regulation mechanism of CYP2E1 expression is poorly described. The present study was aimed to investigate the role of CYP2E1 in acetaminophen (APAP)‐ or tripterygium glycosides (TG)‐induced hepatotoxicity as well as the regulation of CYP2E1 and miR‐378a‐3p expression by APAP or TG. Rats were randomly divided and treated with APAP, TG, chlormethiazole (CMZ), APAP + CMZ and TG + CMZ, respectively, for 4 weeks. Then, blood and liver samples were collected. Serum and hepatic biochemical parameters were measured using commercial kits. Liver histopathology was tested by H&E staining. Expression levels of CYP2E1 mRNA and miR‐378a‐3p were detected by qRT‐PCR. CYP2E1 protein expression was determined by Western blot. Our results showed that CMZ effectively restored the hepatic histopathological changes, oxidative stress biomarkers and TNF‐α levels induced by APAP or TG. CYP2E1 mRNA and/or protein expression levels were dramatically increased after chronic APAP or TG treatment, while this induction was significantly reversed by CMZ co‐treatment. Of note, miR‐378a‐3p expression levels were significantly suppressed after APAP, TG and/or CMZ treatment. These results suggested that CYP2E1 were highly induced after chronic APAP or TG treatment, which in turn play an important role in APAP‐ or TG‐induced hepatotoxicity. These inductions of CYP2E1 expression were probably carried out by inhibition of miR‐378a‐3p. Our findings might provide a new molecular basis for DILI.     

Nilotinib Interferes with the Signalling Pathways Implicated in Acetaminophen Hepatotoxicity

Nilotinib, a second‐generation tyrosine kinase inhibitor, has been recently approved for the treatment for chronic myeloid leukaemia. The objective of this study was to explore the potential effects of clinically relevant doses of nilotinib against acetaminophen (APAP)‐induced hepatotoxicity in mice. To simulate the clinical application in human beings, nilotinib (25 and 50 mg/kg) was administered to mice 2 hr after APAP intoxication (500 mg/kg). The results indicated that nilotinib (25 mg/kg) (i) abolished APAP‐induced liver injury and necro‐inflammation, (ii) increased hepatic‐reduced glutathione (GSH) and its related enzymes synthesis, (iii) suppressed hepatic oxidative/nitrosative stress cascades, (iv) decreased neutrophil accumulation in the liver, and (v) prevented the over‐expression of B‐cell lymphoma‐2 (bcl‐2), cyclin‐D1 and stem cell factor receptor (c‐Kit) proteins in the liver. Although nilotinib (50 mg/kg) acted through the same mechanisms, there was severe depletion in hepatic GSH content by nilotinib itself at that dose level, rather than the potent stimulation observed by using a dose of 25 mg/kg. Consequently, the mortality rate after 18 hr was 100% for nilotinib (50 mg/kg) + APAP (750 mg/kg) versus 60% for APAP (750 mg/kg) and 40% for nilotinib (25 mg/kg) + APAP (750 mg/kg) in the survival analysis experiment. In conclusion, nilotinib can counteract the hepatotoxicity produced by a non‐lethal dose of APAP. However, there is a risk of aggravating the mortality for a lethal dose of APAP when nilotinib is co‐administered at doses relatively high, or near to the clinical range because of hepatic GSH depletion and c‐kit inhibition.     

Effect of S-methylisothiourea in acetaminophen-induced hepatotoxicity in rat

Nitric oxide synthesized from inducible nitric oxide synthase (iNOS) plays role in acetaminophen (APAP)-induced liver damage. The present study was undertaken to evaluate the effect of iNOS inhibitor S-methylisothiourea (SMT) in APAP-induced hepatotoxicity in rats (1?g/kg, i.p.). SMT was (10, 30, and 100?mg/kg; i.p.) given 30?min before and 3?h after APAP administration. At 6 and 24?h, blood was collected to measure alanine transaminase (ALT), aspartate transaminase (AST), and nitrate plus nitrite (NOx) levels in serum. At 48?h, animals were sacrificed, and blood and liver tissues were collected for biochemical estimation. SMT reduced significantly the serum ALT, AST, and NOx levels at 24 and 48?h and liver NOx levels at 48?h as compared with APAP-treated control. The amount of peroxynitrite measured by rhodamine assay was significantly reduced by SMT, as compared with APAP-treated control group. SMT treatment (30?mg/kg) has significantly reduced the lipid peroxidation and protein carbonyl levels, increased SOD and catalase, and reduced glutathione and total thiol levels significantly as compared with APAP-treated control. SMT 30?mg/kg dose has protected animals from APAP-induced hypotension and reduced iNOS gene expression. Hepatocytes were isolated from animals, and effect of SMT on apoptosis, MTP, and ROS generation was studied, and their increased value in APAP intoxicated group was found to be significantly decreased by SMT (30?mg/kg) at 24 and 48?h. In conclusion, nitric oxide produced from iNOS plays important role in toxicity at late hours (24 to 48?h), and SMT inhibits iNOS and reduces oxidative and nitrosative stress.