A Murine Model of Radionuclide Lung Contamination for the Evaluation of Americium Decorporation Treatments Available to Purchase

The hydroxypyridinone ligand 3,4,3-LI(1,2-HOPO) (HOPO), has been previously characterized as a promising chelating agent for in vivo decorporation of actinides, with decorporation being the removal of internally deposited contaminants from the body after exposure. The large majority of relevant literature reports have detailed the efficacy profile of HOPO as a decorporation agent in rodent models, where controlled radionuclide contamination is conducted via intravenous injection. However, this method of contamination does not necessarily reflect an accurate predictive model of the most probable biodistribution of free metal in the body. In the event of a radiological dispersal device or nuclear power plant accident scenario, it is most likely that first responders, military personnel, and victims of the event will be contaminated via air and water transmission. Therefore, research into the efficacy of chelating agents to treat lung-contaminated in vivo models needs to be carried out. Here, we establish a murine model with controlled, reproducible lung contamination using two different radionuclides, ⁸⁹Zr and ²⁴¹Am, for orthogonal biodistribution validation by positron emission tomography and ex vivo radioanalysis, respectively. In addition, we report effective chelation treatment of ²⁴¹Am-contaminated lungs using HOPO, which improves decorporation by up to 40% compared to Ca-DTPA, the current standard of care.