Dataset Information

Novel mechanisms of protection against acetaminophen hepatotoxicity in mice by glutathione and N-acetylcysteine.

ABSTRACT: Acetaminophen (APAP) overdose is a major cause of acute liver failure. The glutathione (GSH) precursor N-acetylcysteine (NAC) is used to treat patients with APAP overdose for up to 48 hours. Although it is well established that early treatment with NAC can improve the scavenging of the reactive metabolite N-acetyl-p-benzoquinone imine, protective mechanisms at later times remain unclear. To address this issue, fasted C3Heb/FeJ mice were treated with 300 mg/kg APAP and then received intravenously 0.65 mmol/kg GSH or NAC at 1.5 hours after APAP. The animals were sacrificed at 6 hours. APAP alone caused severe liver injury with peroxynitrite formation and DNA fragmentation, all of which was attenuated by both treatments. However, GSH (-82%) was more effective than NAC (-46%) in preventing liver injury. Using nuclear magnetic resonance spectroscopy to measure tissue adenosine triphosphate (ATP) levels and the substrate flux through the mitochondrial Krebs cycle, it was observed that the reduced liver injury correlated with accelerated recovery of mitochondrial GSH content, maintenance of ATP levels, and an increased substrate supply for the mitochondrial Krebs cycle compared with APAP alone. NAC treatment was less effective in recovering ATP and mitochondrial GSH levels and showed reduced substrate flux through the Krebs cycle compared with GSH. However, increasing the dose of NAC improved the protective effect similar to GSH, suggesting that the amino acids not used for GSH synthesis were used as mitochondrial energy substrates.Delayed treatment with GSH and NAC protect against APAP overdose by dual mechanisms-that is, by enhancing hepatic and mitochondrial GSH levels (scavenging of reactive oxygen and peroxynitrite)-and by supporting the mitochondrial energy metabolism.

SUBMITTER: Saito C

PROVIDER: S-EPMC2977522 | biostudies-literature | 2010 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Novel mechanisms of protection against acetaminophen hepatotoxicity in mice by glutathione and N-acetylcysteine.

Saito Chieko C Zwingmann Claudia C Jaeschke Hartmut H

Hepatology (Baltimore, Md.) 20100101 1

<h4>Unlabelled</h4>Acetaminophen (APAP) overdose is a major cause of acute liver failure. The glutathione (GSH) precursor N-acetylcysteine (NAC) is used to treat patients with APAP overdose for up to 48 hours. Although it is well established that early treatment with NAC can improve the scavenging of the reactive metabolite N-acetyl-p-benzoquinone imine, protective mechanisms at later times remain unclear. To address this issue, fasted C3Heb/FeJ mice were treated with 300 mg/kg APAP and then rec ...[more]

PMID: 19821517

Similar Datasets

Project description:Acetaminophen (APAP) is a widely available antipyretic and analgesic; however, overdose of the drug inflicts severe damage to the liver. It is well established that the hepatotoxicity of APAP is initiated by formation of a reactive metabolite, N‑acetyl‑p‑benzoquinone imine (NAPQI), which can be detoxified by conjugation with reduced glutathione (GSH), a typical antioxidant. We recently found that the blood mRNA expression level of glutathione peroxidase 3 (Gpx3), which catalyzes the oxidation of GSH, is associated with the extent of APAP‑induced hepatotoxicity in mice. The present study was carried out to determine the in vivo and in vitro role of GPx3 in APAP‑induced hepatotoxicity. In in vivo experiments, oral administration of APAP to mice induced liver injury. Such liver injury was greater in males than in females, although no gender difference in the plasma concentration of APAP was found. Female mice had a 2‑fold higher expression of Gpx3 mRNA and higher plasma GPx activity than male mice. 17β‑estradiol, a major female hormone, decreased APAP‑induced hepatotoxicity and increased both the expression of blood Gpx3 mRNA and plasma GPx activity, suggesting that the cytoprotective action of this hormone is mediated by the increase in GPx3. To further clarify the role of GPx3 in APAP‑induced hepatotoxicity, we evaluated the effect of a change in cellular GPx3 expression resulting from transfection of either siRNA‑GPx3 or a GPx3 expression vector on NAPQI‑induced cellular injury (as assessed by a tetrazolium assay) in in vitro experiments using heterogeneous cultured human cell lines (Huh‑7 or K562). NAPQI‑induced cell death was reduced by increased GPx3 and was enhanced by decreased GPx3. These results suggest that GPx3 is an important factor for inhibition of APAP‑induced hepatotoxicity both in vivo and in vitro. To our knowledge, this is the first report to show a hepatoprotective role of cellular GPx3 against APAP‑induced liver damage.

Dataset Information

Novel mechanisms of protection against acetaminophen hepatotoxicity in mice by glutathione and N-acetylcysteine.

Publications

Novel mechanisms of protection against acetaminophen hepatotoxicity in mice by glutathione and N-acetylcysteine.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets