title: Effects of carbon nanomaterials fullerene C₆₀ and fullerol C₆₀(OH)₁₈₋₂₂ on gills of fish Cyprinus carpio (Cyprinidae) exposed to ultraviolet radiation.
abstract: In consequence of their growing use and demand, the inevitable environmental presence of nanomaterials (NMs) has raised concerns about their potential deleterious effects to aquatic environments. The carbon NM fullerene (C₆₀), which forms colloidal aggregates in water, and its water-soluble derivative fullerol (C₆₀(OH)₁₈₋₂₂), which possesses antioxidant properties, are known to be photo-excited by ultraviolet (UV) or visible light. To investigate their potential hazards to aquatic organisms upon exposure to UV sunlight, this study analyzed (a) the in vitro behavior of fullerene and fullerol against peroxyl radicals (ROO) under UV-A radiation and (b) the effects of these photo-excited NMs on oxidative stress parameters in functional gills extracted from the fish Cyprinus carpio (Cyprinidae). The variables measured were the total antioxidant capacity, lipid peroxidation (TBARS), the activities of the antioxidant enzymes glutathione reductase (GR) and glutamate cysteine ligase (GCL), and the levels of the non-enzymatic antioxidant glutathione (GSH). The obtained results revealed the following: (1) both NMs behaved in vitro as antioxidants against ROO in the dark and as pro-oxidants in presence of UV-A, the latter effect being reversed by the addition of sodium azide, which is a singlet oxygen (¹O₂) quencher; (2) fullerene induced toxicity with or without UV-A incidence, with a significant (p<0.05) increase in lipid peroxidation (with greater damage under illumination), a decrease in GCL activity, and the depletion of GSH stocks (under illumination), all of which were attributed to ¹O₂ generation; and (3) fullerol also decreased GCL activity and GSH formation (p<0.05) but without lipid damage. The overall results show that fullerene can be toxic with or without light incidence, whereas UV radiation seems to play a key role in the environmental toxicity of carbon NMs through ¹O₂ formation.
authors.affiliation: Instituto de Ciências Biológicas, Universidade Federal do Rio Grande-FURG, Campus Carreiros, Av. Itália km 8 s/n, Rio Grande, RS, Brazil.
authors.forename: Roberta
authors.initials: R
authors.lastname: Socoowski Britto
authors.forename: Márcia Longaray
authors.initials: ML
authors.lastname: Garcia
authors.forename: Alessandra
authors.initials: A
authors.lastname: Martins da Rocha
authors.forename: Juliana Artigas
authors.initials: JA
authors.lastname: Flores
authors.forename: Maurício V Brant
authors.initials: MV
authors.lastname: Pinheiro
authors.forename: José María
authors.initials: JM
authors.lastname: Monserrat
authors.forename: Josencler L Ribas
authors.initials: JL
authors.lastname: Ferreira
mesh_terms: D000818:Animals; D002347:Carps; D037741:Fullerenes / Q000633:toxicity*; D005880:Gills / Q000187:drug effects* / Q000528:radiation effects*; D005721:Glutamate-Cysteine Ligase / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D015227:Lipid Peroxidation; D049329:Nanostructures / Q000633:toxicity*; D017392:Thiobarbituric Acid Reactive Substances; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000633:toxicity
chemical_list: D037741:Fullerenes; D017392:Thiobarbituric Acid Reactive Substances; D014874:Water Pollutants, Chemical; C496652:fullerol C60(OH)22; D005721:Glutamate-Cysteine Ligase; D005978:Glutathione; C069837:fullerene C60