Lung O2 metabolism after an acute exposure to transition metals present in nanoparticles

T MARCHINI; N MAGNANI; M GARCÉS; L CACERES; AM MEBERT; MF DESIMONE; LE DIAZ; S ALVAREZ; P EVELSON

Congreso; SETAC Latin America 11th Biennial Meeting; 2015

Presentaciónoral. Several studies have shown that the exposure to commercial or therapeutic nanoparticles (NP) might trigger, under certain conditions, toxic effects over the respiratory system. It is suggested that transition metals present in NP could play an important role in this scenario, via increased production of reactive O2 species and oxidative tissue damage, through Fenton-like chemical reactions. To address this hypothesis, the aim of this work was to study lung O2 metabolism after an acute exposure to transition metal-doped nanoparticles (NP). NP were built by the Stöber method. Their aerodynamic diameter was assessed by dynamic light scattering and metal content by atomic absorption. Female Swiss mice (25 g) were intranasally instilled with a suspension of silica NP containing Ni (II), Cd (II), Fe (III), or Cr (VI); at 0.01, 0.05, 0.1, and 1.0 mg metal/kg body weight. Control mice were handled in parallel and exposed to silica NP without transition metals. Tissue O2 consumption, NADPH oxidase (Nox) activity, and TBARS content were evaluated in lung samples 1 h after instillation. No changes were observed after Cd-NP exposure in any experimental condition. On the contrary, Ni-NP showed a significant increase by 35% to 67% in lung O2 consumption at every tested concentration when compared to the control group (p< 0.05). Likewise, Nox activity and TBARS levels in lung were also significantly increased in every condition, by 41% to 43% and 35 to 51%, respectively (p< 0.05). Regarding Fe-NP, a significant increase in lung O2 consumption by 48% and 52% at 0.1 and 1.0 mg Fe/kg (p< 0.05) was observed when compared to the control group. Nox activity was also increased by 27%, 35%, and 87% at 0.05, 0.01, and 1.0 mg Fe/kg (p< 0.05).