Relevance of the radioprotective effect of sodium selenite

Abstract

Based on the mode of action of Na2SeO3 as a radical scavenger in vitro culture experiments using normal human skin fibroblasts and squamous cell carcinoma cells were performed to investigate the potential role of Na2SeO3 as a radioprotector for normal cells. Therefore, comparative studies of combined treatment, i.e. radiation exposure +/- Na2SeO3 in single-dose (0 to 7 Gy) and multiple fractionated-dose (5 x 2 Gy), were applied to differentiate the radiation response of normal and tumor cells depending upon the treatment protocol. The results indicate that Na2SeO3 under both radiation exposure conditions positively modulates the radiation response of normal fibroblasts in a sense of the radioprotective effect. On the contrary, human tumor cells are not affected by the radioprotective capacity of Na2SeO3 neither under single-dose nor fractionated-dose irradiation. On the basis of the quantitative cell culture analyses, this study indicates for the first time the potential role of Na2SeO3 as a radioprotective compound for normal cells. It will be discussed to what degree differential expression of apoptotic cell death in normal and tumor cells contributes to the radiation response of normal and tumor cells.