Coordinated expression of multidrug resistance-associated proteins (Mrps) in mouse liver during toxicant-induced injury.

Following acute chemical injury, hepatocytes are generally more resistant to toxicant re-exposure. Alterations in expression of hepatobiliary transport systems may contribute to this resistance by preventing accumulation of potentially toxic chemicals. Previous data demonstrate the concomitant reduction of uptake transporter and induction of efflux transporter mRNA during chemical liver injury. The present study further characterizes the expression of multidrug resistance-associated proteins 1-4 (Mrp1-4), breast cancer resistance protein (Bcrp) and sodium-taurocholate co-transporting polypeptide (Ntcp) in mouse liver following administration of the hepatotoxicants acetaminophen (APAP) and carbon tetrachloride (CCl4). Mice received hepatotoxic doses of APAP (400 mg/kg), CCl4 (10 or 25 microl/kg), or vehicle, ip. Livers were collected at 6, 24, and 48 h for Western blot quantification and immunofluorescence analysis. Protein expression of Bcrp was unchanged with treatment. Ntcp levels were preserved in APAP-exposed livers and reduced to 30-50% of control after CCl4. Conversely, Mrp1-4 expression was differentially up-regulated. CCl4 increased Mrp1 (3.5-fold), Mrp2 (1.4-fold), and Mrp4 (26-fold) while reducing Mrp3 levels to 20% of control. Administration of APAP enhanced expression of Mrp2 (1.6-fold), Mrp3 (3.5-fold), and Mrp4 (16-fold). Immunostaining of liver sections obtained 48 h after hepatotoxicant treatment confirmed expression patterns of a subset of transporters (Bcrp, Ntcp, Mrp3, and Mrp4). Double immunofluorescence imaging demonstrated the simultaneous down-regulation of Ntcp and up-regulation of Mrp4 in hepatocytes adjacent to the central vein after CCl4. Altered expression of transporters may reduce the overall chemical burden of an injured liver during recovery and contribute to the resistance of hepatocytes to subsequent toxicant exposure.     

二苯乙烯低聚体对小鼠实验性肝损伤的影响

目的　研究二苯乙烯低聚体(Gn-3)对各种不同类型实验性肝损伤的影响。方法　用小鼠CCl4、醋氨酚和免疫性肝损伤模型,以血清ALT水平,肝脏MDA和GSH含量,肝脏指数和光镜下组织病理变化为观测指标,观察Gn-3预防给药对肝损伤的影响。结果　Gn-3预防给药3d可降低上述3种类型肝损伤小鼠血清ALT水平、肝脏MDA含量,改善组织病理变化,但对肝脏GSH含量无显著影响。结论　Gn-3对3种不同类型的肝损伤均有不同程度的保护作用。     

Pharmacologic inhibition of the renin-angiotensin system did not attenuate hepatic toxicity induced by carbon tetrachloride in rats

The renin-angiotensin system (RAS) subserves vital physiological functions and also implicated in certain pathological states. Modulation of this system has been proposed in recent studies to be a promising strategy in treating liver fibrosis. We investigated the effect of the pharmacologic inhibition of RAS with angiotensin-converting enzyme inhibitor or angiotensin receptor blocker in CCl(4)-induced liver injury with a view to ascertaining the chemopreventive benefit. Fifty-six Wistar albino rats were divided into eight experimental groups of seven rats/group. Groups 1-4 received normal saline (10 ml/kg), enalapril (0.6 mg/kg), losartan (1.4 mg/kg) and CCl(4) (80 mg/kg), respectively. Groups 5-8 were pretreated with enalapril (0.3 mg/kg), enalapril (0.6 mg/kg), losartan (0.7 mg/kg) and losartan (1.4 mg/kg) 1 hour before CCl(4) administration. Experiment lasted 11 days and dosing was via oral route. Rats were killed 24 hours after the last treatment. Serum activities of alkaline phosphatase, aspartate and alanine aminotransferases increased significantly (p < 0.05) by 46.0%, 90.6% and 122.3%, respectively, with severe hepatic centrilobular necrosis, fatty infiltration and increase in liver weight (p < 0.05) in the CCl(4)-treated rats. Enalapril (0.6 mg/kg) and losartan (1.4 mg/kg) significantly (p < 0.05) increased aspartate aminotransferase activity by 37.0% and 94.7% and produced mild centrilobular and periportal hepatic necrosis, respectively, with enalapril significantly (p < 0.05) increasing liver weight. Serum total cholesterol, triglyceride, albumin and total protein did not change significantly in these rats. Also, glutathione, malondialdehyde and uric acid levels were not significantly altered. Enalapril and losartan failed to attenuate liver injury associated with CCl(4) treatment. Although both drugs did not significantly alter serum biochemistry in the CCl(4)-treated rats, they however produced slight elevations in biomarkers of liver function and appear to worsen liver histopathology. Overall, the chemopreventive benefits of RAS inhibitors in liver disease remain doubtful and should be used with caution during hepatic dysfunction.     

复方肝炎平颗粒对CCl4所致小鼠急性肝损伤保护作用

目的 研究复方肝炎平颗粒对CCh所致小鼠急性肝损伤的保护作用，探讨其疗效机制。方法 复方肝炎平连续给于小鼠7天（100．0mg/kg、50．0mg／kg、25．0mg/kg），用CCh造成急性肝损伤，测定小鼠血清中谷丙转氨酶（ALT）和谷草转氨酶（AST）的含量，以及肝组织中超氧化物岐化酶（SOD）、丙二醛（MDA）的含量。结果 复方肝炎平连续给药7天（100．0ms／ks、50．0mg／kg、25．0mg／kg），能抑制小鼠灌胃CCl4引起亚急性肝损伤所致的血清谷丙转氨酶（ALT）和谷草转氨酶（AST）的升高，同时能够升高肝组织中超氧化物岐化酶（SOD）的含量，并能降低丙二醛（MDA）的含量。结论 复方肝炎平颗粒是由苦参、三七等多味中药组成的复方颗粒剂，具有清肝利胆、活血化淤、降酶等功效。复方肝炎平颗粒具有的保肝作用．作用机制可能与其抗脂质过氧化有关。     

Troglitazone enhances the hepatotoxicity of acetaminophen by inducing CYP3A in rats

Troglitazone (TRZ) is the first of a new group of oral antidiabetic drugs, the thiazolidinediones, and is proven to lower plasma glucose levels in patients with type 2 diabetes mellitus. However, the concern has been raised because of several reports, in which severe hepatic dysfunction leading to hepatic failure was demonstrated in a few patients receiving the drug. We studied the effects of TRZ on the hepatotoxicity of carbon tetrachloride (CCl(4)) and acetaminophen (APAP) in rats, both of which exert their toxic effects through bioactivation associated with cytochrome P450 3A (CYP3A) and 2E1 (CYP2E1).Male standard (Wistar/ST) and type 2 diabetic model (GK/Jal) rats were kept on a powdered chow diet containing 0, 100, 500 mg/kg/rat of TRZ. Three weeks later, the rats were either sacrificed for an in vitro metabolism study or challenged with 0.50 g/kg CCl(4) p.o. or 0.75 g/kg APAP i.p.TRZ at 100 and 500 mg/kg/rat increased the CYP3A level as well as the testosterone 6beta-hydroxylation activities in liver microsomes, but did not affect CYP2E1. TRZ also enhanced APAP hepatotoxicity, as evidenced by significantly increased levels of alanine aminotransferase, aspartate aminotransferase and alpha-glutathione S-transferase in the plasma of rats, and by significantly low hepatic glutathione concentration.Our study demonstrated that high doses of TRZ can enhance hepatotoxicity of APAP in Wistar/ST and GK/Jal by inducing hepatic CYP3A.     

A prospective study of multiple supratherapeutic acetaminophen doses in febrile children

Repeated doses of acetaminophen given for therapeutic reasons have been reported to cause hepatotoxicity in adults and children. We studied the effect of repeated acetaminophen (APAP) overdoses administered for therapeutic purposes in a prospective cohort of children. Forty-four children, aged 2 mo to 10 y were referred with a fever of >38.5 C for more than 48 h, and received >60 mg APAP/kg/d. In each patient AST, ALT and APAP blood levels were measured. The mean total daily dose of APAP was 92+/-26 (63-171) mg/kg. There was a weak, but significant, negative correlation between age and daily dose of APAP where younger children received higher doses of APAP. In 4 children (9.1%) an elevation of AST and ALT was found. Three of the 4 patients with elevated liver enzymes had received >90 mg APAP/kg/day; APAP blood levels ranged from 0 to 23 mg/mL. No correlation was found between the time since last APAP dose and the serum drug level. Ill children receiving repeated supratherapeutic doses of acetaminophen may show abnormalities in liver function. However, severe liver injury was rare.     

The impaired disposition of probe drugs is due to both liver and kidney dysfunctions in CCl(4)-model rats

The carbon tetrachloride (CCl(4))-treated model involving mature Sprague-Dawley rats has been historically relied upon to study liver injury and regeneration and to test drug efficacy and disposition. However, there few studies about phase II metabolic enzymes changes in CCl(4)-model rats. The metabolic and excretion tests of phenacetin and acetaminophen (APAP), and the mRNA test of cytochrome P4501A2 (CYP1A2) and phase II metabolic enzymes [sulfotransferase 1A1 (SULT1A1) and UDP-glucuronosyltransferase 1A6 (UGT1A6)] were studied in model rats after CCl(4) pretreatment. The result showed that the function and structure of liver and kidney was impaired by CCl(4) pretreatment, and a significant difference has been observed in the mRNA content of CYP1A2 (p<0.01) in model group, but there was no significant difference on the mRNA content of SULT1A1 and UGT1A6 in both groups. Compared to the control group, a significant higher content of phenacetin (p<0.01) and sulfate-APAP (AS, p<0.01) was observed in the metabolic tests of phenacetin and APAP. Statistically significant differences in cumulative urinary excretion levels of APAP, AG and AS for CCl(4) model rats were observed also. We have shown that impaired disposition of probe drugs in this model was due to both liver and kidney dysfunction in CCl(4)-model rats and we should consider the development of a new liver damage model without renal impairment.     

Sulforaphane protects against acetaminophen-induced hepatotoxicity

Oxidative stress is closely associated with acetaminophen (APAP)-induced toxicity. Heme oxygenase-1 (HO-1), an antioxidant defense enzyme, has been shown to protect against oxidant-induced tissue injury. This study investigated whether sulforaphane (SFN), as a HO-1 inducer, plays a protective role against APAP hepatotoxicity in vitro and in vivo. Pretreatment of primary hepatocyte with SFN induced nuclear factor E2-factor related factor (Nrf2) target gene expression, especially HO-1 mRNA and protein expression, and suppressed APAP-induced glutathione (GSH) depletion and lipid peroxidation, which eventually leads to hepatocyte cell death. A comparable effect was observed in mice treated with APAP. Mice were treated with 300 mg/kg APAP 30 min after SFN (5 mg/kg) administration and were then sacrificed after 6 h. APAP alone caused severe liver injuries as characterized by increased plasma AST and ALT levels, GSH depletion, apoptosis, and 4-hydroxynonenal (4-HNE) formations. This APAP-induced liver damage was significantly attenuated by pretreatment with SFN. Furthermore, while hepatic reactive oxygen species (ROS) levels were increased by APAP exposure, pretreatment with SFN completely blocked ROS formation. These results suggest that SFN plays a protective role against APAP-mediated hepatotoxicity through antioxidant effects mediated by HO-1 induction. SFN has preventive action in oxidative stress-mediated liver injury.     

Inhibition of matrix metalloproteinases minimizes hepatic microvascular injury in response to acetaminophen in mice.

The acetaminophen (APAP)-induced hepatic centrilobular necrosis is preceded by hepatic microcirculatory dysfunction including the infiltration of erythrocytes into the space of Disse. The purpose of this study was to examine the involvement of matrix metalloproteinases (MMPs) in the hepatic microvascular injury elicied by APAP. Male C57Bl/6 mice were pretreated with 2-[(4-biphenylsulfonyl) amino]-3-phenyl-propionic acid, an MMP-2/MMP-9 inhibitor (5 mg/kg, ip) 30 min before oral gavage with 600 mg/kg of APAP. The hepatic microvasculature in anesthetized mice was observed using established in vivo microscopic methods 2 and 6 h after APAP. The levels of mRNAs and activities of MMP-2 and MMP-9 in the liver were increased from 1 h through 6 h after APAP gavage. APAP increased alanine transferase (ALT) levels (41.1-fold) and resulted in centrilobular hemorrhagic necrosis at 6 h. Pretreatment with 2-[(4-biphenylsulfonyl) amino]-3-phenyl-propionic acid attenuated ALT values by 71% as well as the necrosis. APAP decreased the numbers of perfused sinusoids in centrilobular regions by 30% and increased the area occupied by infiltrated erythrocytes into Disse space. 2-[(4-Biphenylsulfonyl) amino]-3-phenyl-propionic acid restored the sinusoidal perfusion to 90% of control levels and minimized extrasinusoidal area occupied by erythrocytes. The present study showed that increased MMPs during APAP intoxication are associated with hepatocellular damage and with hepatic microcirculatory dysfunction including impaired sinusoidal perfusion and infiltration of erythrocytes in Disse space. 2-[(4-Biphenylsulfonyl) amino]-3-phenyl-propionic acid attenuated APAP-induced parenchymal and microvascular injury. These results suggest that MMPs participate in APAP hepatotoxicity mediated by sinusoidal endothelial cell injury, which results in impairment of microcirculation.     

Investigation of the effect of a panel of model hepatotoxins on the Nrf2-Keap1 defence response pathway in CD-1 mice

The Keap1-Nrf2-ARE signalling pathway has emerged as an important regulator of the mammalian defence system to enable detoxification and clearance of foreign chemicals. Recent studies by our group using paracetamol (APAP), diethylmaleate and buthionine sulphoximine have shown that for a given xenobiotic molecule, Nrf2 induction in the murine liver is associated with protein reactivity and glutathione depletion. Here, we have investigated, in vivo, whether the ability of four murine hepatotoxins, paracetamol, bromobenzene (BB), carbon tetrachloride (CCl4) and furosemide (FS) to deplete hepatic glutathione (GSH) is related to induction of hepatic Nrf2 nuclear translocation and Nrf2-dependent gene expression. Additionally, we studied whether hepatic Nrf2 nuclear translocation is a general response during the early stages of acute hepatic chemical stress in vivo. Male CD-1 mice were administered APAP (3.5 mmol/kg), FS (1.21 mmol/kg), BB (4.8 mmol/kg) and CCl4 (1 mmol/kg) for 1, 5 and 24h. Each compound elicited significant serum ALT increases after 24h (ALT U/L: APAP, 3036+/-1462; BB, 5308+/-2210; CCl4, 5089+/-1665; FS, 2301+/-1053), accompanied by centrilobular damage as assessed by histopathology. Treatment with APAP also elicited toxicity at a much earlier time point (5h) than the other hepatotoxins (ALT U/L: APAP, 1780+/-661; BB, 161+/-15; CCl4, 90+/-23; FS, 136+/-27). Significant GSH depletion was seen with APAP (9.6+/-1.7% of control levels) and BB (52.8+/-6.2% of control levels) 1h after administration, but not with FS and CCl4. Western Blot analysis revealed an increase in nuclear Nrf2, 1h after administration of BB (209+/-10% control), CCl4 (146+/-3% control) and FS (254+/-41% control), however this was significantly lower than the levels observed in the APAP-treated mice (462+/-36% control). The levels of Nrf2-dependent gene induction were also analysed by quantitative real-time PCR and Western blotting. Treatment with APAP for 1h caused a significant increase in the levels of haem oxygenase-1 (HO-1; 2.85-fold) and glutamate cysteine ligase (GCLC; 1.62-fold) mRNA. BB and FS did not affect the mRNA levels of either gene after 1h of treatment; however CCl4 significantly increased HO-1 mRNA at this time point. After 24h treatment with the hepatotoxins, there was evidence for the initiation of a late defence response. BB significantly increased both HO-1 and GCLC protein at this time point, CCl4 increased GCLC protein alone, although FS did not alter either of these proteins. In summary, we have demonstrated that the hepatotoxins BB, CCl4 and FS can induce a small but significant increase in Nrf2 accumulation in hepatic nuclei. However, this was associated with modest changes in hepatic GSH, a delayed development of toxicity and was insufficient to activate an early functional adaptive response to these hepatotoxins.     

Antioxidative effect of chitosan on chronic carbon tetrachloride induced hepatic injury in rats

Carbon tetrachloride (CCl(4)) is a toxic material known to induce lipid peroxidation and liver damage. To determine if chitosan has antioxidative effects on CCl(4)-induced liver injury, we administered 1 ml/kg of CCl(4) resolved in a 50% corn oil solution to rats every week by intraperitoneal injection. Chitosan (200 mg/kg body weight per day, MW 380,000 Da) was administered to the CCl(4) + chitosan treated rats by oral gavage during the experimental period. Chitosan significantly decreased liver thiobarbituric acid reactive substances (TBARS) and increased antioxidant enzyme activities (catalase and superoxide dismutase (SOD)). Fatty acid composition was not remarkably changed by chitosan; only arachidonic acid (20:4n-6) levels were significantly altered by CCl(4). Chitosan administration in the present experiment did not restore the decreased delta5-desaturase activity. In addition, chitosan supplementation did not prevent the CCl(4) induced degradation of CYP2E1. In conclusion, our results suggest that chitosan has antioxidative but not detoxifying effects on chronic CCl(4) induced hepatic injury in rats.     

A NO-releasing derivative of acetaminophen spares the liver by acting at several checkpoints in the Fas pathway

NCX-701 is a nitric oxide (NO)-releasing acetaminophen (APAP) derivative. In the present study we demonstrated that NCX-701 is as effective as APAP in controlling body temperature in a rat model of endotoxin-induced fever. Liver toxicity is a major complication of APAP overdosing. To investigate whether NCX-701 is hepatotoxic, BALB/C mice were injected with 100 - 500 mg kg(-1) APAP or NCX-701 alone or in combination (i.e. 500 mg kg(-1) of both compounds). Our results demonstrated that although APAP caused a dose-dependent liver injury, NCX-701 was completely devoid of liver toxicity. At the dose of 500 mg kg(-1) APAP caused an approximately 40 fold increase of AST plasma levels and extensive centrilobular necrosis. APAP and NCX-701 share the same metabolic pathway as demonstrated by the time-course of APAP-glucuronide concentrations in plasma and liver. NCX-701 was safe in mice with pre-existing chronic liver disease. Indeed, while C57BL6 transgenic mice expressing the hepatitis B virus (HBV) at the age of 8 months were significantly more susceptible to liver damage induced by APAP (500 mg kg(-1)) than their congenic littermates, treating HBV-transgenic mice with NCX-701, 500 mg kg(-1), caused no damage. Co-administration of NCX-701 at the dose 500 mg kg(-1) to mice treated with APAP, 500 mg kg(-1), completely protected against liver damage induced by APAP. APAP, but not NCX-701, upregulated liver Fas and Fas Ligand mRNA expression in vivo. Incubating mouse hepatocytes with APAP, but not with NCX-701, increased cell surface Fas expression and sensitized hepatocytes to death induced by challenge with a Fas-agonistic antibody. Collectively, these observations suggest that APAP toxicity is Fas mediated and that NCX-701 spares the liver by acting at several checkpoints in the Fas pathway.     

Plasma microRNAs are sensitive indicators of inter-strain differences in the severity of liver injury induced in mice by a choline- and folate-deficient diet

MicroRNAs (miRNAs) are a class of small, conserved, tissue-specific regulatory non-coding RNAs that modulate a variety of biological processes and play a fundamental role in the pathogenesis of major human diseases, including nonalcoholic fatty liver disease (NAFLD). However, the association between inter-individual differences in susceptibility to NAFLD and altered miRNA expression is largely unknown. In view of this, the goals of the present study were (i) to determine whether or not individual differences in the extent of NAFLD-induced liver injury are associated with altered miRNA expression, and (ii) assess if circulating blood miRNAs may be used as potential biomarkers for the noninvasive evaluation of the severity of NAFLD. A panel of seven genetically diverse strains of inbred male mice (A/J, C57BL/6J, C3H/HeJ, 129S/SvImJ, CAST/EiJ, PWK/PhJ, and WSB/EiJ) were fed a choline- and folate-deficient (CFD) diet for 12 weeks. This diet induced liver injury in all mouse strains; however, the extent of NAFLD-associated pathomorphological changes in the livers was strain-specific, with A/J, C57BL/6J, and C3H/HeJ mice being the least sensitive and WSB/EiJ mice being the most sensitive. The morphological changes in the livers were accompanied by differences in the levels of hepatic and plasma miRNAs. The levels of circulating miR-34a, miR-122, miR-181a, miR-192, and miR-200b miRNAs were significantly correlated with a severity of NAFLD-specific liver pathomorphological features, with the strongest correlation occurring with miR-34a. These observations suggest that the plasma levels of miRNAs may be used as biomarkers for noninvasive monitoring the extent of NAFLD-associated liver injury and susceptibility to NAFLD.     

Effect of pentoxifylline on hepatic injury caused in the rat by the administration of carbon tetrachloride or acetaminophen

The effect of pentoxifylline (PTX) on acute liver injury caused by CCl4 or acetaminophen was studied in the rat. PTX was given twice daily (18, 36 or 72 mg/kg), intraperitoneally (ip) for 5 days prior to CCl4 or acetaminophen. In addition, the effect of PTX administered simultaneously with CCl4 or acetaminophen was evaluated. Rats were killed 72 h or 48 h after CCl4 or acetaminophen administration, respectively. The administration of PTX at 72 mg/kg, conferred significant protection against the hepatotoxic actions of CCl4, reducing serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP) levels to 31%, 59.2% and 63%, respectively. Histological examination showed a decrease in centrilobular necrotic areas in rats pretreated with PTX. Histochemical investigation revealed a decrease in glycogen and protein contents caused by CCl4 and these were prevented by PTX pretreatment. When administered with CCl4, PTX did not reduce CCl4-induced hepatic injury. In contrast, hepatic injury induced by acetaminophen was prevented by prior or co-treatment with PTX. Accordingly, with 72 mg/kg of PTX, the elevation of AST, ALT and ALP levels was lower by 45%, 80.6%, 54.3% for the former and by 32.4%, 77.2%, 52.4% for the latter, respectively. Stained sections were subjected to morphometric evaluation using computerized image analyzer. Quantitative analysis of the acetaminophen area of damage showed a reduction by 34.8, 65.5 and 89.2% by 18, 36 or 72 mg/kg for PTX, respectively. Rats treated with PTX revealed more or less normal hepatocyte architecture as well as marked improvement in protein and glycogen content. The study demonstrates that prior but not co-toxicant administration of PTX in a model of CCl4-induced liver injury results in less liver damage. In contrast, PTX is equally protective, when given either as a pretreatment or with acetaminophen exposure.     

Study on early biomarkers of zebrafish liver injury induced by acetaminophen

The aim of this study was to systematically study zebrafish model to predict drug-induced liver injury (DILI) with the drug acetaminophen (APAP) and find the sensitive early biomarkers. The concentration–toxicity relationship was determined at concentrations 1, 2, 4, 8, 16?mmol/L of APAP. APAP caused a concentration-dependent mortality of zebrafish. APAP caused a time-dependent mortality. Mild to severe vacuolar degeneration of liver cells were observed. APAP increased serum alanine aminotransferase (ALT), lactate dehydrogenase (LDH) and xanthine oxidase (XOD) levels significantly, while it delevated argininosuccinic acid lyase (ASAL) and total bile acid (TBA) levels. TBA and ASAL were more sensitive than ALT in this process. Zebrafish may be a convenient, practical and valuable biological model to predict DILI.     

降脂利肝颗粒对小鼠急性肝损伤的保护作用

目的：研究降脂利肝颗粒对急性肝损伤小鼠的保护作用。方法：以四氯化碳（CCl4）诱导急性肝损伤制作肝损伤小鼠模型，分别给予低（100mg／kg）、中（300mg／kg）、高（900mg／kg）3个剂量的降脂利肝颗粒浸膏，以联苯双酯（200mg／kg）为阳性对照药物，检测血清中丙氨酸氨基转移酶（ALT）和门冬氨酸氨基转移酶（AST）的水平，并进行病理学检查。结果：与模型对照组比较，降脂利肝颗粒浸膏低、中、高3个剂量组ALT和AST水平显著降低（P〈0．05）。降脂利肝颗粒浸膏低剂量组降低ALT水平的作用不如阳性对照联苯双酯组明显，中、高剂量组作用与联苯双酯组相似。降脂利肝颗粒浸膏低、中、高3个剂量组均能减轻肝组织病理损伤程度。结论：降脂利肝颗粒对小鼠急性肝损伤具有较好的保护作用。     

3,4-Dihydroxyphenylacetic acid,a microbiota-derived metabolite of quercetin,attenuates acetaminophen (APAP)-induced liver injury through activation of Nrf-2

1. Acetaminophen (APAP) overdose leads to severe hepatotoxicity. 3,4-dihydroxyphenylacetic acid (DOPAC) is a scarcely studied microbiota-derived metabolite of quercetin. The aim of this study was to determine the protective effect of DOPAC against APAP-induced liver injury.

2. Mice were treated intragastrically with DOPAC (10, 20 or 50?mg/kg) for 3 days before APAP (300?mg/kg) injection. APAP alone caused increase in serum aminotransferase levels and changes in hepatic histopathology. APAP also promoted oxidative stress by increasing lipid peroxidation and decreasing anti-oxidant enzyme activities. These events led to hepatocellular necrosis and reduced liver function. DOPAC increased nuclear factor erythroid 2-related factor 2 (Nrf-2) translocation to the nucleus and enhanced the expression of phase II enzymes and anti-oxidant enzymes, and thereby reduced APAP hepatotoxicity and enhanced anti-oxidant ability.

3. Our data provide evidence that DOPAC protected the liver against APAP-induced injury, which is involved in Nrf-2 activation, implying that DOPAC can be considered as a potential natural hepatoprotective agent.     

肝心康胶囊对小鼠肝损伤的保护作用

目的 观察肝心康胶囊(GXK)对小鼠3种肝损伤模型的保护作用：方法采用四氯化碳(CCl4)、对乙酰氨基酚(APAP)、D-氨基半乳糖 脂多糖(D-GalN LPS)致小鼠肝损伤的3种模型，测定用药前后血清谷丙转氨酶(ALT)。结果GXK能明显降低CCl4,APAP,D-GalN LPS引起的肝损伤后小鼠血清中升高的ALT水平。结论GXK对实验性肝损伤有明显的保护作用。