title: The nitric oxide donor, V-PYRRO/NO, protects against acetaminophen-induced hepatotoxicity in mice.
abstract: The liver-selective nitric oxide (NO) donor, O(2)-vinyl 1-(pyrrolidin-1-yl)diazen-1-ium-1,2-diolate (V-PYRRO/NO), is metabolized by P-450 enzymes to release NO in the liver, and is shown to protect the liver from tumor necrosis factor alpha (TNF-alpha)-induced apoptosis and D-glactosamine/endotoxin-induced hepatotoxicity. This study was undertaken to examine the effects of V-PYRRO/NO on acetaminophen-induced hepatotoxicity in mice. Mice were given V-PYRRO/NO via osmotic pumps (1.8-5.4 mg/mL, 8 microL/h) 4 to 16 hours before a hepatotoxic dose of acetaminophen (600 mg/kg, intraperitoneally [ip]). V-PYRRO/NO administration dramatically reduced acetaminophen-induced hepatotoxicity in a dose- and time-dependent manner, as evidenced by reduced serum alanine aminotransferase (ALT) activity, reduced hepatic congestion, apoptosis, and improved hepatocellular pathology. The protection afforded by V-PYRRO/NO does not appear to be caused by a decrease in the formation of toxic acetaminophen metabolites, which consumes glutathione (GSH), because V-PYRRO/NO did not alter acetaminophen-induced hepatic GSH depletion. Acetaminophen-induced lipid peroxidation, as determined by the concentrations of 4-hydroxyalkenals (4-HNE) and malondialdehyde (MDA), was reduced significantly by V-PYRRO/NO treatment. Although pretreatment was most effective, administration of V-PYRRO/NO simultaneously with acetaminophen also was able to reduce acetaminophen hepatotoxicity. Genomic analysis of the liver samples 10 hours after acetaminophen intoxication showed the enhanced expression of genes associated with stress/oxidative stress, apoptosis/cell death, and DNA damage/repair. Acetaminophen-induced alterations in gene expression were attenuated significantly by V-PYRRO/NO. Real-time reverse-transcription polymerase chain reaction (RT-PCR) and Western-blot analysis confirmed microarray results. In conclusion, V-PYRRO/NO is effective in blocking acetaminophen-induced hepatotoxicity in mice. This protection may involve the reduction of oxidative stress, the inhibition of apoptosis, and possibly the maintenance of hepatic vasculature to prevent congestion.
authors.affiliation: Inorganic Carcinogenesis Section, Laboratory of Comparative Carcinogenesis, National Cancer Institute at the National Institute of Environmental Health Sciences (NIEHS), Research Triangle Park, NC 27709, USA. Liu6@niehs.nih.gov
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.forename: Chengxiu
authors.initials: C
authors.lastname: Li
authors.forename: Michael P
authors.initials: MP
authors.lastname: Waalkes
authors.forename: James
authors.initials: J
authors.lastname: Clark
authors.forename: Page
authors.initials: P
authors.lastname: Myers
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Saavedra
authors.forename: Larry K
authors.initials: LK
authors.lastname: Keefer
mesh_terms: D000082:Acetaminophen / Q000506:poisoning*; D000818:Animals; D015153:Blotting, Western; D002614:Chelating Agents / Q000506:poisoning*; D056486:Chemical and Drug Induced Liver Injury; D003199:Computer Systems; D019610:Cytoprotection; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D008099:Liver / Q000187:drug effects* / Q000473:pathology; D008107:Liver Diseases / Q000401:mortality / Q000517:prevention & control; D051379:Mice; D008815:Mice, Inbred Strains; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D020411:Oligonucleotide Array Sequence Analysis; D011759:Pyrrolidines / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D002614:Chelating Agents; D020030:Nitric Oxide Donors; C107010:O(2)-vinyl-1-(pyrrolidin-1-yl)diazen-1-ium-1,2-diolate; D011759:Pyrrolidines; D000082:Acetaminophen