title: Silver nanocolloids disrupt medaka embryogenesis through vital gene expressions.
abstract: Silver nanomaterials are the major components of healthcare products largely because of their antimicrobial effects. However, their unintended toxicity to biological organisms and its mechanism are not well understood. Using medaka fish embryo model, the toxic effects and corresponding mechanisms of silver nanocolloids (SNC, particle size 3.8 ± 1.0-diameter nm) were investigated. SNC caused morphological changes in embryos including cardiovascular malformations, ischemia, underdeveloped central nervous system and eyes, and kyphosis at exposures of 0.5 mg/L. Interestingly, SNC were observed inside the eggs at a level of 786.1 ± 32.5 pg/mg egg weight, and TEM analysis showed that SNC adhered to the surface and inside of the chorion. Meanwhile, medaka oligo DNA microarray and qRT-PCR were used for gene expression analysis in the embryos exposed to 0.05 mg/L SNC for 48 h. As a result, expressions of six of the oxidative stress-, embryogenesis- and morphogenesis-related genes, ctsL, tpm1, rbp, mt, atp2a1, and hox6b6, were affected by the SNC exposure, and these genes' involvement in those malformations was implied. Thus, SNC could potentially cause malformations in the cardiovascular and central nervous systems in developing medaka embryo through SNC-induced differential expression of the genes related to oxidative stress, embryonic cellular proliferation, and morphological development.
authors.affiliation: Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, South Carolina 29208, United States. kashiwada@toyo.jp
authors.forename: Shosaku
authors.initials: S
authors.lastname: Kashiwada
authors.forename: Maria E
authors.initials: ME
authors.lastname: Ariza
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Kawaguchi
authors.forename: Yuya
authors.initials: Y
authors.lastname: Nakagame
authors.forename: B Sumith
authors.initials: BS
authors.lastname: Jayasinghe
authors.forename: Karin
authors.initials: K
authors.lastname: Gärtner
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nakamura
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kagami
authors.forename: Tara
authors.initials: T
authors.lastname: Sabo-Attwood
authors.forename: P Lee
authors.initials: PL
authors.lastname: Ferguson
authors.forename: G Thomas
authors.initials: GT
authors.lastname: Chandler
mesh_terms: D000375:Aging / Q000187:drug effects; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D003102:Colloids / Q000633:toxicity; D004625:Embryo, Nonmammalian / Q000002:abnormalities / Q000187:drug effects / Q000378:metabolism; D047108:Embryonic Development / Q000187:drug effects* / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects*; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D053768:Metal Nanoparticles / Q000633:toxicity* / Q000648:ultrastructure; D009024:Morphogenesis / Q000187:drug effects / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D009990:Oryzias / Q000196:embryology* / Q000235:genetics*; D018384:Oxidative Stress / Q000187:drug effects; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012834:Silver / Q000633:toxicity*; D012996:Solutions; D018675:Toxicity Tests
chemical_list: D015415:Biomarkers; D003102:Colloids; D012996:Solutions; D012834:Silver