title: Hemocyte responses of Dreissena polymorpha following a short-term in vivo exposure to titanium dioxide nanoparticles: preliminary investigations.
abstract: The widespread use of titanium-based nanoparticles and their environmental release may pose a significant risk to aquatic organisms within freshwater ecosystems. Suspension-feeder invertebrates like bivalve molluscs represent a unique target group for nanoparticle toxicology. The aim of this work was to investigate the short-term responses of Dreissena polymorpha hemocytes after in vivo exposure to titanium dioxide nanoparticles (TiO(2) NP). For this purpose, freshwater mussels were exposed to P25 TiO(2) NP at the concentrations of 0.1, 1, 5 and 25mg/L during 24h. Viability, phagocytosis activity and mitogen activated protein kinase (MAPK) phosphorylation level of ERK 1/2 and p38 in hemocytes extracted from exposed mussels were compared to those from control specimens. Results demonstrated an inhibition of the phagocytosis activity after exposure to TiO(2) NP at 0.1 and 1mg/L. Similar trends, albeit less pronounced, were reported for higher concentrations of NP. Transmission electron microscopy showed for the first time the internalization of TiO(2) NP into Dreissena polymorpha hemocytes. Besides, exposure to NP increased the ERK 1/2 phosphorylation levels in all treatments. Concerning the phosphorylation level of p38, only exposures to 5 and 25mg/L of NP induced significant p38 activation in comparison to that of the control. Finally, these short-term effects observed at environmentally relevant concentrations highlighted the need for further studies concerning ecotoxicological evaluation of nanoparticle release into an aquatic environment.
authors.affiliation: Université de Lorraine, Laboratoire des Interactions Ecotoxicologie, Biodiversité, Ecosystèmes, CNRS UMR 7146, IUT Thionville-Yutz, Espace Cormontaigne, Yutz, F-57970, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Couleau
authors.forename: Didier
authors.initials: D
authors.lastname: Techer
authors.forename: Christophe
authors.initials: C
authors.lastname: Pagnout
authors.forename: Stéphane
authors.initials: S
authors.lastname: Jomini
authors.forename: Laurent
authors.initials: L
authors.lastname: Foucaud
authors.forename: Philippe
authors.initials: P
authors.lastname: Laval-Gilly
authors.forename: Jairo
authors.initials: J
authors.lastname: Falla
authors.forename: Amar
authors.initials: A
authors.lastname: Bennasroune
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D049875:Dreissena / Q000187:drug effects*; D005602:France; D006434:Hemocytes / Q000187:drug effects*; D046529:Microscopy, Electron, Transmission; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D053758:Nanoparticles / Q000633:toxicity*; D010587:Phagocytosis / Q000187:drug effects; D010766:Phosphorylation / Q000187:drug effects; D013778:Tetrazolium Salts; D013844:Thiazoles; D014025:Titanium / Q000633:toxicity*; D014961:X-Ray Diffraction
chemical_list: D013778:Tetrazolium Salts; D013844:Thiazoles; C009495:titanium dioxide; D014025:Titanium; D020928:Mitogen-Activated Protein Kinases; C022616:thiazolyl blue