ミヤヤマ　タカミツ   Takamitsu Miyayama   宮山　貴光    所属   医学部 医学科    職種   助教
言語種別	英語
発表タイトル	Cellular distribution of silver nanoparticles and behavior of metallothionein in human bronchial epithelial cells
会議名	6th International Symposium on Nanotechnology, Occupational and Environmental Health
主催者	6th International Symposium on Nanotechnology, Occupational and Environmental Health Organizing Committee
学会区分	国際学会及び海外の学会
発表形式	ポスター掲示
講演区分	一般
発表者・共同発表者	◎MIYAYAMA Takamitsu, ARAI Yuta, SUZUKI Noriyuki, HIRANO Seishiro
発表年月日	2013/10/28
開催地 （都市, 国名）	Nagoya, Japan
学会抄録	Abstract:6th International Symposium on Nanotechnology, Occupational and Environmental Health 86
概要	Silver nanoparticles (AgNPs) are commercially used as antibacterial reagents. However, the mechanisms underlying Ag toxicity in mammals are not fully understood. In the present study, we assessed distribution and toxicity of AgNPs and silver nitrite (AgNO3) in human bronchial epithelial cell (BEAS-2B) focusing on behavior of metallothionein (MT). The cells were exposed to 0 - 500 μg Ag/mL AgNPs or 0 - 100 μmol/L AgNO3 for up to 24 h. The cytotoxicity was assayed by a modified MTT method. The cellular concentration and distribution of Ag were evaluated by ICP-MS and laser scanning microscopy, respectively. Distribution of Ag to MT and other proteins was determined using HPLC-ICP-MS. Ag was distributed to MT in AgNPs exposed cells in a time-dependent manner, suggesting that soluble As was released from AgNPs. On the other hand, cellular Ag concentration and Ag-bound MT (Ag-MT) were sharply increased up to 3 h and then decreased in AgNO3-exposed cells. The agglomerated AgNPs were found in lysosomes at 24 h after exposure. ROS generation occurred in the mitochondria following treatment with AgNO3. The effect of Ag on respiration in rat liver mitochondria was assessed by measuring O2 consumption. Exposure to AgNO3 resulted in a dose-dependent decrease in mitochondrial oxygen consumption as AgNO3 inhibited the electron transport chain enzymes associated with complexes I-IV in mitochondria. ROS production appeared to cause relocation of Ag-MT to mitochondria, which evoked inhibition of electron transport chain. These results suggest that the difference in cytotoxicity between AgNP and AgNO3 is probably due to the stability of Ag-MT and degradation of Ag-MT may lead to cell damage.
researchmap用URL	http://square.umin.ac.jp/nanoeh6/index.html