title: Melatonin prevents the decreased activity of antioxidant enzymes and activates nuclear erythroid 2-related factor 2 signaling in an animal model of fulminant hepatic failure of viral origin.
abstract: This work was undertaken to investigate whether treatment with melatonin prevents oxidative stress and changes in the expression and activity of factor erythroid 2-related factor 2 (Nrf2)-mediated antioxidant enzymes in an animal model of fulminant hepatic failure of viral origin. Rabbits were experimentally infected with 2 x 10(4) hemagglutination units of a rabbit hemorrhagic disease virus (RHDV) isolate and received melatonin at two concentrations of 10 mg/kg and 20 mg/kg at 0, 12 and 24 hr postinfection. Blood transaminases, blood lactate dehydrogenase, liver concentration of thiobarbituric reactive acid substances and the liver oxidized to reduced glutathione ratio significantly increased at 36 hr postinfection in infected animals. Significant decreases were found in the mRNA levels and in the liver activities of Mn-superoxide dismutase, glutathione peroxidase and glutathione-S-transferase in infected rabbits. These effects were prevented by melatonin administration in a concentration-dependent manner. Melatonin treatment was not accompanied by changes in protein levels of Kelch-like ECH-associating protein 1 (Keap1) but resulted in an increased protein expression of Nrf2 in the cytoplasm and the nucleus, which was confirmed by the results of Nrf2 immunostaining. Nuclear extracts from livers of melatonin-treated rats displayed an enhanced antioxidant responsive element (ARE)-binding activity of Nrf2. Our results suggest a potential hepatoprotective role of melatonin in fulminant hepatic failure, partially mediated through the abrogation of oxidative stress and the prevention of the decreased activity of antioxidant enzymes via the Nrf2 pathways.
authors.affiliation: Institute of Biomedicine (IBIOMED), University of León, León, Spain.
authors.forename: Irene
authors.initials: I
authors.lastname: Crespo
authors.forename: Beatriz S
authors.initials: BS
authors.lastname: Miguel
authors.forename: Almudena
authors.initials: A
authors.lastname: Laliena
authors.forename: Marcelino
authors.initials: M
authors.lastname: Alvarez
authors.forename: Jesús M
authors.initials: JM
authors.lastname: Culebras
authors.forename: Javier
authors.initials: J
authors.lastname: González-Gallego
authors.forename: María J
authors.initials: MJ
authors.lastname: Tuñón
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D015153:Blotting, Western; D002467:Cell Nucleus / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000235:genetics / Q000378:metabolism; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism; D017929:Hemorrhagic Disease Virus, Rabbit; D007150:Immunohistochemistry; D017114:Liver Failure, Acute / Q000201:enzymology / Q000378:metabolism* / Q000821:virology; D008297:Male; D008550:Melatonin / Q000494:pharmacology*; D051267:NF-E2-Related Factor 2 / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects; D020011:Protective Agents; D012333:RNA, Messenger / Q000378:metabolism; D011817:Rabbits; D015398:Signal Transduction / Q000187:drug effects*; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism
chemical_list: D000975:Antioxidants; D051267:NF-E2-Related Factor 2; D020011:Protective Agents; D012333:RNA, Messenger; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D005982:Glutathione Transferase; D008550:Melatonin