2017 Volume 65 Issue 3 Pages 261-267
Radioactive nuclides leak into the surrounding environment after nuclear power plant disasters, such as the Chernobyl accident and the Fukushima Daiichi Nuclear Power Plant disaster. Cesium-137 (137Cs) (t1/2=30.1 year), a water-soluble radionuclide with a long physical half-life, contaminates aquatic ecosystems and food products. In humans, 137Cs concentrates in muscle tissue and has a long biological half-life, indicating it may be harmful. myo-Inositol-hexakisphosphate (IP6) is a compound found in grain, beans, and oil seeds. IP6 has the ability to form insoluble complexes with metals, including lanthanum (La) and zinc (Zn). We hypothesized that La-IP6 and Zn-IP6 may promote the elimination of 137Cs from the body through the adsorption of La-IP6 and Zn-IP6 to 137Cs in the gastrointestinal tract. Therefore, in this study, we evaluated the adsorptive capacity of La-IP6 and Zn-IP6 complexes with 137Cs in vitro and in vivo. La-IP6 and Zn-IP6 complexes were stable in acidic solution (pH 1.2) at 37°C. In vitro binding assays indicated that La-IP6 and Zn-IP6 complexes adsorbed 137Cs, with the adsorption capacity of Zn-IP6 to 137Cs greater than that of La-IP6. To evaluate the usefulness of La-IP6 and Zn-IP6 in vivo, La-IP6 or Zn-IP6 was administrated to mice after intravenous injection of 137Cs. However, the biodistribution of 137Cs in the La-IP6 treated group and the Zn-IP6 treated group was nearly identical to the non-treated control group, indicating that La-IP6 and Zn-IP6 were not effective at promoting the elimination of 137Cs in vivo.