title: Stepwise embryonic toxicity of silver nanoparticles on Oryzias latipes.
abstract: The developmental toxicity of silver nanoparticles (AgNPs) was investigated following exposure of Oryzias latipes (medaka) embryos to 0.1-1 mg/L of homogeneously dispersed AgNPs for 14 days. During this period, developmental endpoints, including lethality, heart rate, and hatching rate, were evaluated by microscopy for different stages of medaka embryonic development. To compare toxic sensitivity, acute adult toxicity was assessed. There was no difference in acute lethal toxicity between embryo and adult medaka. Interestingly, we found that the increase in stepwise toxicity was dependent on the developmental stage of the embryo. Lethal embryonic toxicity increased from exposure days 1 to 3 and exposure days 5 to 8, whereas there was no change from exposure days 3 to 5. In addition, 7 d exposure to 0.8 mg/L AgNPs resulted in significant heart beat retardation in medaka embryos. AgNPs also caused a dose-dependent decrease in the hatching rate and body length of larvae. These results indicate that AgNP exposure causes severe developmental toxicity to medaka embryos and that toxicity levels are enhanced at certain developmental stages, which should be taken into consideration in assessments of metallic NPs toxicity to embryos.
authors.affiliation: Risk Assessment Division, National Institute of Environmental Research, Kyungseo-Dong, Seo-gu, Incheon 404-170, Republic of Korea.
authors.forename: Jae-Gu
authors.initials: JG
authors.lastname: Cho
authors.forename: Kyung-Tae
authors.initials: KT
authors.lastname: Kim
authors.forename: Tae-Kwon
authors.initials: TK
authors.lastname: Ryu
authors.forename: Jae-woo
authors.initials: JW
authors.lastname: Lee
authors.forename: Ji-Eun
authors.initials: JE
authors.lastname: Kim
authors.forename: Jungkon
authors.initials: J
authors.lastname: Kim
authors.forename: Byoung-Cheun
authors.initials: BC
authors.lastname: Lee
authors.forename: Eun-Hye
authors.initials: EH
authors.lastname: Jo
authors.forename: Junheon
authors.initials: J
authors.lastname: Yoon
authors.forename: Ig-chun
authors.initials: IC
authors.lastname: Eom
authors.forename: Kyunghee
authors.initials: K
authors.lastname: Choi
authors.forename: Pilje
authors.initials: P
authors.lastname: Kim
mesh_terms: D000818:Animals; D004625:Embryo, Nonmammalian / Q000187:drug effects* / Q000473:pathology*; D005618:Fresh Water; D006339:Heart Rate / Q000187:drug effects; D020128:Inhibitory Concentration 50; D053768:Metal Nanoparticles / Q000633:toxicity* / Q000648:ultrastructure; D009990:Oryzias / Q000033:anatomy & histology / Q000196:embryology*; D012834:Silver / Q000633:toxicity*; D023382:Toxicity Tests, Acute
chemical_list: D012834:Silver