3-nitrotyrosine and Drug-Overdose

Acetaminphen (APAP) overdose leads to severe hepatotoxicity. Apocynum venetum L. (A. venetum) possess potent hepatoprotective effect. Hyperoside is one of the major compounds exist in Apocynum venetum L. and might be a potential agent to protect against APAP-induce liver injury. In this study, we investigated the effect of hyperoside on APAP hepatotoxicity in mice. Mice were treated intragastrically with hyperoside (10, 50 or 100 mg/kg) for 3 days before APAP (300 mg/kg) injection. APAP alone caused severe liver injury characterized by significantly increased serum aminotransferase levels, hepatic malondialdehyde (MDA) and 3-nitrotyrosine (3-NT) formation, as well as liver superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione (GSH) depletions. Hyperoside significantly attenuated APAP-induced liver damages in a dose dependent manner, and 100 mg/kg was the most effective dose. Further study confirmed that hyperoside was able to increase activities and mRNA expressions of uridine diphoshate glucuronosyltransferases (UGTs) and sulfotransferases (SULTs), as well as to inhibit CYP2E1 activities, and thereby suppressed toxic intermediate formation and promoted APAP hepatic detoxification. Nrf-2 activation might be involved in hyperoside induced up-regulation of phase II enzymes. Collectively, our data provide evidence that hyperoside protected the liver against APAP induced injury mainly by accelerating APAP harmless metabolism, implying that hyperoside can be considered as a potential natural hepatoprotective agent.

Topics: Acetaminophen; Animals; Chemical and Drug Induced Liver Injury; Cytochrome P-450 CYP2E1; Drug Overdose; Gene Expression Regulation, Enzymologic; Glucuronosyltransferase; Liver; Male; Mice; NF-E2-Related Factor 2; Oxidative Stress; Quercetin; RNA, Messenger; Sulfotransferases; Tyrosine

Stable hydrophilic C60(OH)10 nanoparticles were prepared from 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) and applied to the treatment of an acetaminophen overdose induced liver Injury. C60(OH)10 nanoparticles were produced by cogrinding α-CD, β-CD, γ-CD and HP-β-CD and characterized in terms of solubility, mean particle diameter, ζ-potential and long term dispersibility in water. Hydrophilic C60(OH)10 nanoparticles with particle sizes less than 50 nm were effectively produced by cogrinding HP-β-CD with C60(OH)10 at a molar ratio of 1:3 (C60(OH)10:CD). The resulting C60(OH)10/HP-β-CD nanoparticles were stable in water and showed no aggregation over a 1 month period. The C60(OH)10/CDs nanoparticles scavenged not only free radicals (DPPH and ABTS radicals) but also reactive oxygen species (O2(•-) and •OH). When C60(OH)10/HP-β-CD nanoparticles were intraperitoneally administered to mice with a liver injury induced by an overdose of acetaminophen (APAP), the ALT and AST levels were markedly reduced to almost the same level as that for normal mice. Furthermore, the administration of the nanoparticles prolonged the survival rate of liver injured mice, while all of the mice that were treated with APAP died within 40 h. To reveal the mechanism responsible for liver protection by C60(OH)10 nanoparticles, GSH level, CYP2E1 expression and peroxynitrite formation in the liver were assessed. C60(OH)10/HP-β-CD nanoparticles had no effect on CYP2E1 expression and GSH depletion, but suppressed the generation of peroxynitrite in the liver. The findings indicate that the protective effect of C60(OH)10/HP-β-CD nanoparticles was due to the suppression of oxidative stress in mitochondria, as the result of scavenging ROS such as O2(•-), NO and peroxynitrite, which act as critical mediators in the liver injuries.

Topics: 2-Hydroxypropyl-beta-cyclodextrin; Acetaminophen; Animals; Antioxidants; Benzothiazoles; beta-Cyclodextrins; Biphenyl Compounds; Chemical and Drug Induced Liver Injury; Cytochrome P-450 CYP2E1; Drug Overdose; Electron Spin Resonance Spectroscopy; Free Radical Scavengers; Fullerenes; Glutathione; Hydrophobic and Hydrophilic Interactions; Hydroxylation; Liver; Male; Mice, Inbred C57BL; Nanoparticles; Nitric Oxide; Oxidative Stress; Particle Size; Peroxynitrous Acid; Picrates; Protective Agents; Solubility; Static Electricity; Sulfonic Acids; Tyrosine

Overdose of acetaminophen (APAP) is a common cause of acute liver injury and liver failure. The mechanism involves formation of a reactive metabolite, protein binding, oxidative stress and activation of c-Jun N-terminal kinase (JNK), mitochondrial dysfunction, and nuclear DNA fragmentation caused by endonucleases released from damaged mitochondria. Previous work has shown that the natural product resveratrol (RSV) can protect against APAP hepatotoxicity in mice through prevention of lipid peroxidation and anti-inflammatory effects. However, these earlier studies did not take into consideration several fundamental aspects of the pathophysiology. To address this, we treated C57Bl/6 mice with 300 mg/kg APAP followed by 50 mg/kg RSV 1.5 h later. Our results confirmed that RSV reduced liver injury after APAP overdose in mice. Importantly, RSV did not inhibit reactive metabolite formation and protein bindings, nor did it reduce activation of JNK. However, RSV decreased protein nitration after APAP treatment, possibly through direct scavenging of peroxynitrite. Interestingly, RSV also inhibited release of apoptosis-inducing factor and endonuclease G from mitochondria independent of Bax pore formation and prevented the downstream nuclear DNA fragmentation. Our data show that RSV protects against APAP hepatotoxicity both through antioxidant effects and by preventing mitochondrial release of endonucleases and nuclear DNA damage.

Topics: Acetaminophen; Animals; Apoptosis Inducing Factor; Chemical and Drug Induced Liver Injury; DNA Fragmentation; Drug Overdose; Endonucleases; Hepatocytes; JNK Mitogen-Activated Protein Kinases; Liver; Male; Mice; Mice, Inbred C57BL; Mitochondria; Oxidative Stress; Peroxynitrous Acid; Protein Binding; Resveratrol; Stilbenes; Tyrosine