%0 Journal Article %T Rat pulmonary responses to inhaled nano-TiO₂: effect of primary particle size and agglomeration state. %+ Département de santé environnementale et de santé au travail %+ Institut Armand Frappier (INRS-IAF) %+ Institut de recherche Robert-Sauvé en santé et en sécurité du travail (IRSST) %A Noël, Alexandra %A Charbonneau, Michel %A Cloutier, Yves %A Tardif, Robert %A Truchon, Ginette %Z This work was supported by a grant from the Réseau de recherche en santéenvironnementale du Québec (RRSE) and the Institut de recherche en santépublique de l’Université de Montréal (IRSPUM). %< avec comité de lecture %@ 1743-8977 %J Particle and Fibre Toxicology %I BioMed Central %V 10 %P 48 %8 2013-10-04 %D 2013 %R 10.1186/1743-8977-10-48 %M 24090040 %K TiO2 nanoparticles %K Inhalation %K Agglomeration state %K Primary particle size %K Inflammation %K Cytotoxicity %K Oxidative stress %Z Life Sciences [q-bio] %Z Life Sciences [q-bio]/Microbiology and Parasitology/BacteriologyJournal articles %X The exact role of primary nanoparticle (NP) size and their degree of agglomeration in aerosols on the determination of pulmonary effects is still poorly understood. Smaller NP are thought to have greater biological reactivity, but their level of agglomeration in an aerosol may also have an impact on pulmonary response. The aim of this study was to investigate the role of primary NP size and the agglomeration state in aerosols, using well-characterized TiO₂ NP, on their relative pulmonary toxicity, through inflammatory, cytotoxic and oxidative stress effects in Fisher 344 male rats. Three different sizes of TiO₂ NP, i.e., 5, 10-30 or 50 nm, were inhaled as small (SA) (< 100 nm) or large agglomerates (LA) (> 100 nm) at 20 mg/m³ for 6 hours. Compared to the controls, bronchoalveolar lavage fluids (BALF) showed that LA aerosols induced an acute inflammatory response, characterized by a significant increase in the number of neutrophils, while SA aerosols produced significant oxidative stress damages and cytotoxicity. Data also demonstrate that for an agglomeration state smaller than 100 nm, the 5 nm particles caused a significant increase in cytotoxic effects compared to controls (assessed by an increase in LDH activity), while oxidative damage measured by 8-isoprostane concentration was less when compared to 10-30 and 50 nm particles. In both SA and LA aerosols, the 10-30 nm TiO₂ NP size induced the most pronounced pro-inflammatory effects compared to controls. Overall, this study showed that initial NP size and agglomeration state are key determinants of nano-TiO₂ lung inflammatory reaction, cytotoxic and oxidative stress induced effects. %G English %2 https://riip.hal.science/pasteur-01132013/document %2 https://riip.hal.science/pasteur-01132013/file/1743-8977-10-48.pdf %L pasteur-01132013 %U https://riip.hal.science/pasteur-01132013 %~ RIIP %~ INRS-IAF