title: Induction of oxidative stress and apoptosis by silver nanoparticles in the liver of adult zebrafish.
abstract: Silver nanoparticles (AgNPs) may induce deleterious effects in aquatic life on environmental release. The hepatotoxicity of AgNPs was assessed in the liver of adult zebrafish, with the aim of studying the roles of oxidative damage and apoptosis. Zebrafish were exposed to an AgNP solution in which free Ag+ ions were absent at the time of treatment. However, the metal-sensitive metallothionein 2 (MT2) mRNA was induced in the liver tissues of AgNP-treated zebrafish, suggesting that Ag+ ions were released from AgNPs after treatment. It is also possible that MT2 mRNA was induced in the liver tissues by AgNP-generated free radicals. A number of cellular alterations including disruption of hepatic cell cords and apoptotic changes were observed in histological analysis of the liver tissues. The levels of malondialdehyde, a byproduct of cellular lipid peroxidation, and total glutathione were increased in the tissues after treatment with AgNPs. The mRNA levels of the oxyradical-scavenging enzymes catalase and glutathione peroxidase 1a were reduced in the tissues. AgNP treatment induced DNA damage, as demonstrated by analysis with the double-strand break marker γ-H2AX and the expression of p53 protein in liver tissues. In addition, the p53-related pro-apoptotic genes Bax, Noxa, and p21 were upregulated after treatment with AgNPs. These data suggest that oxidative stress and apoptosis are associated with AgNP toxicity in the liver of adult zebrafish.
authors.affiliation: College of Veterinary Medicine, Seoul National University, 599 Gwanak, Gwanak, Seoul, 151-742, Republic of Korea.
authors.forename: Ji Eun
authors.initials: JE
authors.lastname: Choi
authors.forename: Soohee
authors.initials: S
authors.lastname: Kim
authors.forename: Jin Hee
authors.initials: JH
authors.lastname: Ahn
authors.forename: Pilju
authors.initials: P
authors.lastname: Youn
authors.forename: Jin Seok
authors.initials: JS
authors.lastname: Kang
authors.forename: Kwangsik
authors.initials: K
authors.lastname: Park
authors.forename: Jongheop
authors.initials: J
authors.lastname: Yi
authors.forename: Doug-Young
authors.initials: DY
authors.lastname: Ryu
mesh_terms: D000818:Animals; D017209:Apoptosis; D002374:Catalase / Q000235:genetics / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000235:genetics / Q000378:metabolism; D008099:Liver / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D008315:Malondialdehyde / Q000378:metabolism; D053768:Metal Nanoparticles / Q000633:toxicity* / Q000648:ultrastructure; D008668:Metallothionein / Q000235:genetics / Q000378:metabolism; D018384:Oxidative Stress; D012834:Silver / Q000378:metabolism / Q000633:toxicity*; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism; D000072105:Superoxide Dismutase-1; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D015027:Zebrafish / Q000502:physiology*; D000094765:Glutathione Peroxidase GPX1
chemical_list: D014874:Water Pollutants, Chemical; D012834:Silver; D008315:Malondialdehyde; D008668:Metallothionein; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1; D005978:Glutathione; D000094765:Glutathione Peroxidase GPX1