Influence of Eu(III) and U(VI) on rat and human kidney cells

Radionuclides (RNs) that enter the human body, for example through ingestion or inhalation, pose a potential health risk due to their radio- and chemotoxicity. The kidneys are especially exposed to the incorporated RNs, as they are mainly responsible for the excretion of toxic substances from the blood stream. Therefore, the effect of uranium(VI) and europium(III), an analogue for trivalent actinides such as Am or Cm, on rat (NRK-52E) and human (HEK-293) kidney cells was studied in vitro at the cellular and molecular levels.
Exposure experiments were carried out in which cells were incubated with these metal ions (10−9 – 10−3 M) for 7, 24 and 48 hours. The cell viability after exposure to the metal ions was measured using the XTT-assay. The half-maximum effective concentration (EC50) was calculated on the basis of the dose-response curves. In addition, morphological changes due to metal ion exposure were investigated by staining selected cell compartments and intracellular uptake was determined by ICP-MS. The speciation of a metal determines its bioavailability, influencing both the effect on cells and its uptake into cells. Therefore, time resolved laser-induced fluorescence spectroscopy (TRLFS) was used to investigate the speciation of Eu(III) and U(VI) in the cell culture medium, in the cell-exposed medium and in cell suspension. The obtained results on the cellular and molecular level contribute to a better understanding of the toxic effects of RNs.
This work is funded in the frame of the RADEKOR project by the German Federal Ministry of Education and Research (BMBF, grant number: 02NUK057A and 02NUK057B).