Acetaminophen Toxicity in Mice Lacking NADPH Oxidase Activity: Role of Peroxynitrite Formation and Mitochondrial Oxidant Stress

Abstract

Previous data have indicated that activated macrophages may play a role in the mediation of acetaminophen toxicity. In the present study, we examined the significance of superoxide produced by macrophages by comparing the toxicity of acetaminophen in wild-type mice to mice deficient in gp91phox, a critical subunit of NADPH oxidase that is the primary source of phagocytic superoxide. Both groups of mice were dosed with 300 mg/kg of acetaminophen or saline and sacrificed at 1, 2, 4 or 24 h. Glutathione in total liver and in mitochondria was depleted by approximately 90% at 1 h in wild-type and knock out mice. No significant differences in toxicity (serum transaminase levels or histopathology) were observed between wild-type and mice deficient in gp91phox. Mitochondrial glutathione disulfide, as a percent of total glutathione, was determined as a measure of oxidant stress produced by increased superoxide, leading to hydrogen peroxide and/or peroxynitrite. The percent mitochondrial glutathione disulfide increased to approximately 60% at 1 h and 70% at 2 h in both groups of mice. Immunohistochemical staining for nitrotyrosine was present in vascular endothelial cells at 1 h in both groups of mice. Acetaminophen protein adducts were present in hepatocytes at 1 h in both wild-type and knock out animals. These data indicate that superoxide from activated macrophages is not critical to the development of acetaminophen toxicity and provide further support for the role of mitochondrial oxidant stress in acetaminophen toxicity.

Protective effect of Panax ginseng against N-acetyl-p-aminophenol-induced hepatotoxicity in rats

“…This metabolite depletes hepatic glutathione and then binds covalently to intracellular proteins, including mitochondrial proteins. This situation leads to the formation of reactive oxygen and nitrogen species, and initiates lipid peroxidation that eventually results in destruction, necrosis, or apoptosis of the liver cells (Hinson et al, 2004;James et al, 2003;Nelson, 1990). N-Acetylcysteine (NAC) is the antidote for acetaminophen poisoning because of its ability to increase the available glutathione for conjugation with NAPQI (Tucker, 1998).…”

Systems Biology Investigation to Discover Metabolic Biomarkers of Acetaminophen-Induced Hepatic Injury Using Integrated Transcriptomics and Metabolomics

“…NO can also react with oxygen radicals to form reactive nitrogen species peroxynitrite, which can damage macromolecules such as enzymes in the mitochondria via oxidation, hydroxylation and nitration [41,42]. NOS have been found to be involved with APAP toxicity [42]. For example, neuronal NOS (nNOS) was reported to be related to the deactivation of manganese superoxide dismutase in a study comparing neuronal NOS knockout and wild-type mice dosed with 300 mg APAP/kg [43].…”

“…Blood arginine levels can also be affected by nitric oxide synthases (NOSs), which convert arginine to citrulline and nitric oxide (NO; an important signaling molecule to control blood pressure, insulin secretion and nervous system development, etc.). NO can also react with oxygen radicals to form reactive nitrogen species peroxynitrite, which can damage macromolecules such as enzymes in the mitochondria via oxidation, hydroxylation and nitration [41,42]. NOS have been found to be involved with APAP toxicity [42].…”

Isolation, Structure Elucidation of Ferulic and Coumaric acids from Fortunella japonica Swingle leaves and their Structure Antioxidant activity relationship

“…14 On the other hand, at over dosages, paracetamol is metabolized by the cytochrome P450 (CYP450) oxidative system that is mainly localized in the liver endoplasmic reticulum, and generates N-acetyl-p-benzoquinone-imine (NAPQI). 15 This metabolite depletes hepatic glutathione and then binds covalently to intracellular proteins, including mitochondrial proteins. 15 This situation leads to the formation of reactive oxygen and nitrogen species, and initiates lipid peroxidation that eventually results in destruction, necrosis, or apoptosis of the liver cells.…”

“…15 This metabolite depletes hepatic glutathione and then binds covalently to intracellular proteins, including mitochondrial proteins. 15 This situation leads to the formation of reactive oxygen and nitrogen species, and initiates lipid peroxidation that eventually results in destruction, necrosis, or apoptosis of the liver cells. 14 In continuation of our interested research program in the isolation and therapeutic evaluation of natural products, 16,17 the present study report here in, a facile route to isolate ferulic and coumaric acids from Fortunella japonica Swingle leaves and investigate their in-vitro hepatoprotective effects against paracetamol-induced oxidative damages in isolated hepatocytes.…”