Takamitsu Miyayama    Department   School of Medicine, School of Medicine    Position   Assistant Professor
Language	English
Title	Metabolic behavior and effects of ion and nanoparticle forms of silver in the mouse lung and macrophages
Conference	53rd annual meeting and ToxExpo: Society of Toxicology 2014
Conference Type	International society and overseas society
Presentation Type	Poster notice
Lecture Type	General
Publisher and common publisher	◎MIYAYAMA Takamitsu, ARAI Yuta, HIRANO Seishiro
Date	2014/03/25
Venue (city and name of the country)	Phoenix, USA
Society abstract	The Toxicologist in 53rd Annual Meeting and ToxExpo: Society of Toxicology 213 2014
Summary	Health effects of silver nanoparticles (AgNPs) have not been well investigated, although AgNPs are now widely used in consumer products. We have investigated metabolic behavior and inflammatory responses of intratracheally instilled AgNPs and silver nitrate (AgNO3) in the mouse lungs. Male ICR mice were administered with AgNPs or AgNO3 at a dose of 10μg Ag per animal. Contents of Ag in lungs of the AgNPs-treated mice were significantly and 4.27 and 4.47 times higher than those of the AgNO3-treated mice at 4 and 24 h post administration, respectively. In the AgNO3-treated mice, Ag concentration in the lungs was not changed between 4 and 24 h. To evaluate neutrophil and pro-inflammatory cytokines after AgNPs or AgNO3 instillation, we performed bronchoalveolar lavage (BAL) to mice. AgNO3 significantly increased numbers of neutrophils at 24 h after instillation. On the other hand, AgNPs slightly increased neutrophil numbers at 24 h. In the BAL fluid (BALF), the concentrations of IL-1β significantly increased 24 h after AgNO3 and AgNPs instillation. We also investigated uptake and intracellular distribution of Ag in vitro exposing mouse macrophage cell cells (J774.1) to either AgNO3 or AgNPs. Ag was located to the insoluble fraction of the cells after exposure to AgNPs in a time dependent manner. Ag bound metallothionein (MT), which was measured by HPLC-ICP-MS, increased up to 3 h in J774.1 cells following exposure to AgNO3. On the other hand, Ag was not distributed to MTs and localized in lysosomes following exposure to AgNPs. These results suggest that AgNPs were first incorporated in lysosomes of macrophages and induced inflammatory stimuli to the cells or tissues. In contrast AgNO3 probably induced inflammatory stimuli first and increased Ag-bound MT levels in the cytosol.
URL for researchmap	http://www.toxicology.org/AI/MEET/AM2014/