title: Nickel affects gill and muscle development in oriental fire-bellied toad (Bombina orientalis) embryos.
abstract: The developmental toxicity of nickel was examined in the embryos of Bombina orientalis, a common amphibian in Korea. Based on a standard frog embryo teratogenesis assay, the LC50and EC50for malformation of nickel after 168h of treatment were 33.8μM and 5.4μM, respectively. At a lethal concentration (100μM), nickel treatment decreased the space between gill filaments and caused epithelial swelling and abnormal fusion of gill filaments. These findings suggest that nickel affects the functional development of gills, leading to embryonic death. At sublethal concentrations (1-10μM), nickel produced multiple embryonic abnormalities, including bent tail and tail dysplasia. At 10μM, nickel significantly decreased tail length and tail muscle fiber density in tadpoles, indicating inhibition of myogenic differentiation. Before hatching, the pre-muscular response to muscular response stages (stages 26-31) were the most sensitive period to nickel with respect to tail muscle development. During these stages, MyoD mRNA was upregulated, whereas myogenic regulatory factor 4 mRNA was downregulated by 0.1μM nickel. Calcium-dependent kinase activities in muscular response stage embryos were significantly decreased by nickel, whereas these activities were restored by exogenous calcium. In tadpoles, 10μM nickel significantly decreased the expression of the myosin heavy chain and the 12/101 muscle marker protein in the tail. Expression was restored by exogenous calcium. Our results indicate that nickel affects muscle development by disrupting calcium-dependent myogenesis in developing B. orientalis embryos.
authors.affiliation: Department of Life Science and Institute for Natural Sciences, Hanyang University, Seoul 133-791, South Korea.
authors.forename: Chan Jin
authors.initials: CJ
authors.lastname: Park
authors.affiliation: Department of Life Science and Institute for Natural Sciences, Hanyang University, Seoul 133-791, South Korea.
authors.forename: Sang Ha
authors.initials: SH
authors.lastname: Song
authors.affiliation: Department of Life Science and Institute for Natural Sciences, Hanyang University, Seoul 133-791, South Korea.
authors.forename: Dae Han
authors.initials: DH
authors.lastname: Kim
authors.affiliation: Department of Life Science and Institute for Natural Sciences, Hanyang University, Seoul 133-791, South Korea. Electronic address: mcgye@hanyang.ac.kr.
authors.forename: Myung Chan
authors.initials: MC
authors.lastname: Gye
mesh_terms: D000818:Animals; D001001:Anura / Q000196:embryology*; D004625:Embryo, Nonmammalian; D047108:Embryonic Development / Q000187:drug effects*; D005880:Gills / Q000187:drug effects* / Q000196:embryology; D007814:Larva; D024510:Muscle Development / Q000187:drug effects*; D009532:Nickel / Q000633:toxicity*; D056910:Republic of Korea; D014874:Water Pollutants, Chemical / Q000633:toxicity
chemical_list: D014874:Water Pollutants, Chemical; D009532:Nickel
keywords: Bombina orientalis; Embryonic toxicity; Muscle; Myogenesis; Nickel