title: Tissue specific responses to cadmium-based quantum dots in the marine mussel Mytilus galloprovincialis.
abstract: In recent years, Cd-based quantum dots (QDs) have generated interest from the life sciences community due to their potential applications in nanomedicine, biology and electronics. However, these engineered nanomaterials can be released into the marine environment, where their environmental health hazards remain unclear. This study investigated the tissue-specific responses related to alterations in the antioxidant defense system induced by CdTe QDs, in comparison with its dissolved counterpart, using the marine mussel Mytilus galloprovincialis. Mussels were exposed to CdTe QDs and dissolved Cd for 14 days at 10 μgCd L(-1) and biomarkers of oxidative stress [superoxide dismutase (SOD), catalase (CAT), glutathione peroxidases (total, Se-independent and Se-dependent GPx) and glutathione-S-transferase (GST) activities] were analyzed along with Cd accumulation in the gills and digestive gland of mussels. Results show that both Cd forms changed mussels' antioxidant responses with distinct modes of action (MoA). There were tissue- and time-dependent differences in the biochemical responses to each Cd form, wherein QDs are more pro-oxidant when compared to dissolved Cd. The gills are the main tissue affected by QDs, with effects related to the increase of SOD, GST and GPx activities, while those of dissolved Cd was associated to the increase of CAT activity, Cd accumulation and exposure time. Digestive gland is a main tissue for accumulation of both Cd forms, but changes in antioxidant enzyme activities are smaller than in gills. A multivariate analysis revealed that the antioxidant patterns are tissue dependent, indicating nano-specific effects possibly associated to oxidative stress and changes in redox homeostasis.
authors.affiliation: CIMA, Faculty of Science and Technology, University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.
authors.forename: Thiago Lopes
authors.initials: TL
authors.lastname: Rocha
authors.affiliation: CIMA, Faculty of Science and Technology, University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal; Norwegian Institute for Water Research (NIVA), Gaustadalléen 21, NO-0349 Oslo, Norway.
authors.forename: Tânia
authors.initials: T
authors.lastname: Gomes
authors.affiliation: CIMA, Faculty of Science and Technology, University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.
authors.forename: Nélia C
authors.initials: NC
authors.lastname: Mestre
authors.affiliation: CIMA, Faculty of Science and Technology, University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.
authors.forename: Cátia
authors.initials: C
authors.lastname: Cardoso
authors.affiliation: CIMA, Faculty of Science and Technology, University of Algarve, Campus de Gambelas, 8005-139 Faro, Portugal. Electronic address: mbebian@ualg.pt.
authors.forename: Maria João
authors.initials: MJ
authors.lastname: Bebianno
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D002104:Cadmium / Q000493:pharmacokinetics / Q000633:toxicity*; D002374:Catalase / Q000378:metabolism; D004064:Digestive System / Q000737:chemistry / Q000187:drug effects / Q000201:enzymology; D005880:Gills / Q000737:chemistry / Q000187:drug effects / Q000201:enzymology; D005979:Glutathione Peroxidase / Q000378:metabolism; D049878:Mytilus / Q000737:chemistry / Q000187:drug effects* / Q000201:enzymology; D018384:Oxidative Stress / Q000187:drug effects; D010316:Particle Size; D045663:Quantum Dots / Q000633:toxicity*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D014018:Tissue Distribution; D014874:Water Pollutants, Chemical / Q000493:pharmacokinetics / Q000633:toxicity*
chemical_list: D000975:Antioxidants; D017382:Reactive Oxygen Species; D014874:Water Pollutants, Chemical; D002104:Cadmium; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase
keywords: CdTe quantum dots; Ecotoxicology; Metal-based nanoparticle; Nanomaterials; Oxidative stress