title: Silver nanoparticles affect the neural development of zebrafish embryos.
abstract: Silver nanoparticles (AgNPs) have been widely used in commercial products. This study aims to understand the impact of AgNPs on the early developmental stages in zebrafish (Danio rerio) embryos. Embryos were exposed to two sizes of AgNPs at three dose levels, as well to free Ag(+) ions, for a range of 4-96 h post-fertilization (hpf). The acute exposure study showed that exposure to AgNPs affected the neurological development, and the exposed embryos exhibited anomalies such as small head with hypoplastic hindbrain, small eye and cardiac defects. At the molecular level, AgNPs altered the expression profiles of neural development-related genes (gfap, huC and ngn1), metal-sensitive metallothioneins and ABCC genes in exposed embryos. The expression of AhR2 and Cyp1A, which are usually considered to mediate polycyclic aromatic hydrocarbon toxicity, were also significantly changed. A size-dependent uptake of AgNPs was observed, whereby 4 nm AgNPs were more efficiently taken up compared with the 10 nm-sized particles. Importantly, the head area accumulated AgNPs more efficiently than the trunk area of exposed zebrafish embryos. No free Ag(+) ions, which can be potentially released from the AgNP solutions, were detected. This study suggests that AgNPs could affect the neural development of zebrafish embryos, and the toxicity of AgNPs may be partially attributed to the comparatively higher uptake in the head area. These results indicate the potential neurotoxicity of AgNPs and could be extended to other aquatic organisms.
authors.affiliation: State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, 200062, China.|City University of Hong Kong Shenzhen Research Institute, Shenzhen, 518057, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Xin
authors.affiliation: School of Biological, Biomedical & Environmental Sciences, University of Hull, Cottingham Road, Hull, HU6 7RX, UK.
authors.forename: Jeanette M
authors.initials: JM
authors.lastname: Rotchell
authors.affiliation: State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, 200062, China.|City University of Hong Kong Shenzhen Research Institute, Shenzhen, 518057, China.|Environmental Science Programs, School of Science, Hong Kong University of Science and Technology, Clear Water bay, Kowloon, Hong Kong, China.
authors.forename: Jinping
authors.initials: J
authors.lastname: Cheng
authors.affiliation: State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, 200062, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Yi
authors.affiliation: State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, 200062, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D004625:Embryo, Nonmammalian / Q000002:abnormalities / Q000187:drug effects*; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects*; D053768:Metal Nanoparticles / Q000633:toxicity*; D009420:Nervous System / Q000187:drug effects* / Q000196:embryology; D038081:Organogenesis / Q000187:drug effects* / Q000235:genetics; D012834:Silver / Q000633:toxicity*; D013550:Swimming; D015027:Zebrafish / Q000196:embryology*
chemical_list: D012834:Silver
keywords: cardiotoxicity; developmental toxicity; gene expression; nanotoxicity; neurotoxicity; silver nanoparticles; zebrafish embryos