Experimental immunology
The effect of selenium on redox state and thiols changes in lung tissue after Selol, a new organoselenium (IV) compound, administration

Selol is a product containing organoselenium compounds, where selenium (Se) exists at a +4 oxidation state. Bonding of Se (IV) into organic compounds is responsible for high bioavailability and low toxicity, while the presence of Se in its +4 oxidative state influences biological activity. Studies on sodium selenite (IV) show that it undergoes redox reactions in the presence of glutathione, which, in turn, produce reactive oxygen species. At the same time Se is widely known to be an anti-oxidative agent. Due to intracellular reactions Se affects an oxidation-reduction potential of cells. Changes of the potential correlate with the cell biological state: proliferation undergoes at a potential about –240 mV and apoptosis is induced at potentials higher than –170 mV. The aim of the study was to test the effect of Selol 2% on the oxidation-reduction potential in lung tissue of healthy rats and to determine changes in concentration of thiol compounds involved in glutathione metabolism in relation to the amount of Se adsorbed by the lungs. A new HPLC method with sensitive fluorescence detection was developed to separate the relevant thiols: glutathione, cysteine, homocysteine, -glutamylcysteine, and cysteinylglycine. The Se content in lung tissue was assayed using ICP-MS. A single administration of Selol 2% to healthy rats caused a ten-fold increase in Se content in lung cells, with a maximum value occurring at 2 h. During the first four hours, Selol showed a pro-oxidative effect characterised by decrease in GSH concentration and increase in redox potential level and CysGly concentration. After four hours an anti-oxidative effect related to decrease in the potential and an induction of GSH synthesis from its precursors was observed. The oxidative stress induced initially by Selol was finally overcame. The cells reached a better redox state than prior to the administration of Selol, which leads to the conclusion that the compound does not have a negative effect on healthy cells.