Uranium micro localization in the femur of rats exposed to uranium acetate

• Published in: Microchemical journal 2024-12, Vol.207, p.112278, Article 112278
• Main Authors: Kato, Yugo, Yakumaru, Haruko, Ayama, Kyoko, Terauchi, Miyu, Numako, Chiya, Sekizawa, Oki, Nitta, Kiyofumi, Homma-Takeda, Shino
• Format: Article
• Language: English
• Subjects: Bone; Elemental imaging; SR-XRF; Uranium
• ISSN: 0026-265X
• DOI: 10.1016/j.microc.2024.112278

[Display omitted] •A new type of thin section standard was used for detection of uranium concentration in matrix-rich bone by SR-XRF.•Uranium concentration at bone sites was estimated to be 20% lower than at bone marrow due to matrix effects.•Uranium is distributed in bone formation areas in the rat femur, with concentrations exceeding 1000 µg/g. Uranium is a radionuclide that causes internal exposure, with the bone being one of its primary sites of retention. However, the precise localization of uranium within the bone is not well known. In this study, we analyzed the distribution of uranium in the femur of rats exposed to uranium. For our analysis, we used synchrotron radiation X-ray fluorescence analysis with high-energy excitation X-rays with microbeam (high-energy SR-µXRF). To quantify uranium in bone tissues, we modified our previously developed thin-section standards. Additionally, we prepared droplet standards for quantifying bone calcium. Our findings showed that uranium concentration at bone sites was estimated to be 20% lower than at bone marrow sites of the same intensity, likely owing to matrix effects. The elemental mapping of the femur’s frozen section specimens showed that uranium was distributed in a very limited surface layer bordering the bone marrow, one day post-administration.