Peroxynitrite is a critical mediator of acetaminophen hepatotoxicity in murine livers: protection by glutathione

J Pharmacol Exp Ther. 2002 Nov;303(2):468-75. doi: 10.1124/jpet.102.038968.

Abstract

Acetaminophen (AAP) overdose causes formation of nitrotyrosine, a footprint of peroxynitrite, in centrilobular hepatocytes. The importance of peroxynitrite for the pathophysiology, however, is unclear. C3Heb/FeJ mice were treated with 300 mg/kg AAP. To accelerate the restoration of hepatic glutathione (GSH) levels as potential endogenous scavengers of peroxynitrite, some groups of animals received 200 mg of GSH/kg i.v. at different time points after AAP. AAP induced severe liver cell damage at 6 h. Total liver and mitochondrial glutathione levels decreased by >90% at 1 h but recovered to 75 and 45%, respectively, of untreated values at 6 h after AAP. In addition, the hepatic and mitochondrial glutathione disulfide (GSSG) content was significantly increased over baseline, suggesting a mitochondrial oxidant stress. Moreover, centrilobular hepatocytes stained for nitrotyrosine. Treatment with GSH at t = 0 restored hepatic GSH levels and completely prevented the mitochondrial oxidant stress, peroxynitrite formation, and liver cell injury. In contrast, treatment at 1.5 and 2.25 h restored hepatic and mitochondrial GSH levels but did not prevent the increase in GSSG formation. Nitrotyrosine adduct formation and liver injury, however, was substantially reduced. GSH treatment at 3 h after AAP was ineffective. Similar results were obtained when these experiments were repeated with glutathione peroxidase-deficient animals. Our data suggest that early GSH treatment (t = 0) prevented cell injury by improving the detoxification of the reactive metabolite of AAP. Delayed GSH treatment enhanced hepatic GSH levels, which scavenged peroxynitrite in a spontaneous reaction. Thus, peroxynitrite is an important mediator of AAP-induced liver cell necrosis.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acetaminophen / antagonists & inhibitors
  • Acetaminophen / toxicity*
  • Alanine Transaminase / metabolism
  • Analgesics, Non-Narcotic / antagonists & inhibitors
  • Analgesics, Non-Narcotic / toxicity*
  • Animals
  • Antidotes / administration & dosage
  • Antidotes / metabolism
  • Antidotes / therapeutic use*
  • Chemical and Drug Induced Liver Injury / pathology*
  • Glutathione / administration & dosage
  • Glutathione / metabolism
  • Glutathione / therapeutic use*
  • Immunohistochemistry
  • Injections, Intravenous
  • Liver / pathology*
  • Male
  • Mice
  • Mice, Inbred C3H
  • Mitochondria, Liver / metabolism
  • Necrosis
  • Peroxynitrous Acid / metabolism
  • Peroxynitrous Acid / physiology*
  • Serum Albumin, Bovine / chemistry
  • Tyrosine / analogs & derivatives*
  • Tyrosine / metabolism

Substances

  • Analgesics, Non-Narcotic
  • Antidotes
  • Peroxynitrous Acid
  • Serum Albumin, Bovine
  • 3-nitrotyrosine
  • Acetaminophen
  • Tyrosine
  • Alanine Transaminase
  • Glutathione