title: Micro-distribution of uranium in bone after contamination: new insight into its mechanism of accumulation into bone tissue.
abstract: After internal contamination, uranium rapidly distributes in the body; up to 20 % of the initial dose is retained in the skeleton, where it remains for years. Several studies suggest that uranium has a deleterious effect on the bone cell system, but little is known regarding the mechanisms leading to accumulation of uranium in bone tissue. We have performed synchrotron radiation-based micro-X-ray fluorescence (SR μ-XRF) studies to assess the initial distribution of uranium within cortical and trabecular bones in contaminated rats' femurs at the micrometer scale. This sensitive technique with high spatial resolution is the only method available that can be successfully applied, given the small amount of uranium in bone tissue. Uranium was found preferentially located in calcifying zones in exposed rats and rapidly accumulates in the endosteal and periosteal area of femoral metaphyses, in calcifying cartilage and in recently formed bone tissue along trabecular bone. Furthermore, specific localized areas with high accumulation of uranium were observed in regions identified as micro-vessels and on bone trabeculae. These observations are of high importance in the study of the accumulation of uranium in bone tissue, as the generally proposed passive chemical sorption on the surface of the inorganic part (apatite) of bone tissue cannot account for these results. Our study opens original perspectives in the field of exogenous metal bio-mineralization.
authors.affiliation: ICSM, LHYS, BP 17171, 30207, Bagnols-sur-Cèze, France, damien.bourgeois@cea.fr.
authors.forename: Damien
authors.initials: D
authors.lastname: Bourgeois
authors.forename: Brigitte
authors.initials: B
authors.lastname: Burt-Pichat
authors.forename: Xavier
authors.initials: X
authors.lastname: Le Goff
authors.forename: Jan
authors.initials: J
authors.lastname: Garrevoet
authors.forename: Pieter
authors.initials: P
authors.lastname: Tack
authors.forename: Gerald
authors.initials: G
authors.lastname: Falkenberg
authors.forename: Luc
authors.initials: L
authors.lastname: Van Hoorebeke
authors.forename: Laszlo
authors.initials: L
authors.lastname: Vincze
authors.forename: Melissa A
authors.initials: MA
authors.lastname: Denecke
authors.forename: Daniel
authors.initials: D
authors.lastname: Meyer
authors.forename: Claude
authors.initials: C
authors.lastname: Vidaud
authors.forename: Georges
authors.initials: G
authors.lastname: Boivin
mesh_terms: D065638:Absorption, Radiation / Q000502:physiology; D000818:Animals; D005269:Femur / Q000737:chemistry / Q000166:cytology / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D000069079:Radiation Exposure / Q000032:analysis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013052:Spectrometry, X-Ray Emission / Q000379:methods*; D014018:Tissue Distribution; D014501:Uranium / Q000032:analysis / Q000493:pharmacokinetics*
chemical_list: D014501:Uranium