Brain accumulation of inhaled uranium in the rat depends on aerosol concentration, exposure repetitions, particle size and solubility

Benjamin Tournier (1) , Chrystelle Ibanez (2) , Elie Tourlonias (3) , Fabrice Petitot (4) , Francois Paquet (5) , Isabelle Dublineau (6) , Philippe Lestaevel (7)

1 Division of Adult Psychiatry, Department of Psychiatry
2 IRSN/PSE-SANTE/SESANE/LRTOX - Laboratoire de radiotoxicologie et radiobiologie expérimentale
3 Nucléagis SAS
4 DEN, DUSP, Service de Protection contre les Rayonnements - CEA,
5 IRSN/PSE-ENV/SEREN - Service d'expertise et d'étude en radioprotection des populations et de la radioactivité dans l'environnement
6 IRSN/PSE-ENV/SEDRE/USDR - Unité d'expertise des sites et des déchets radioactifs
7 IRSN/PSE-SANTE/SER/BASEP - Bureau d'analyse et de suivi des expositions professionnelles

A rostro-caudal gradient of uranium (U) in the brain has been suggested after its inhalation. To study thefactors influencing this mapping, we first used 30-min acute inhalation at 56 mg/m3 of the relatively soluble form UO4 in the rat. These exposure parameterswere then used as a reference in comparison with the other experimental conditions. Other groups received acute inhalation at different concentrations, repeated low dose inhalation of UO4 (10 exposures) or acute low dose inhalation of the insoluble form UO2. At 24 hafter the last exposure, all rats showed a brain U accumulation with a rostro-caudal gradient as compared to controls. However, the total concentration to the brain was greater after repeated exposure than acute exposure, demonstrating an accumulative effect. In comparison with the low dose soluble U exposure, a higher accumulation in the front of the brain was observed after exposure to higher dose, to insoluble particles and following repetition of exposures, thus demonstrating a dose effect and influences of solubility and repetition of exposures. In the last part, exposure to ultrafine U particles made it possible to show 24 h after exposure the presence of U in the brain according to a rostro-caudal gradient. Finally, the time-course after exposure to micronic or nanometric U particles has revealed greater residence times for nanoparticles.

Domaines: Sciences du Vivant [q-bio]

Benjamin Tournier, Chrystelle Ibanez, Elie Tourlonias, Fabrice Petitot, Francois Paquet, et al.. Brain accumulation of inhaled uranium in the rat depends on aerosol concentration, exposure repetitions, particle size and solubility. Toxicology Letters, 2021, pp.10-17. ⟨10.1016/j.toxlet.2021.08.002⟩. ⟨hal-03409664⟩