Radio-protective effects of selenium in rats

The aim of this study was to evaluate the potential radio-protective effects of different selenium supplement concentrations of 4, 8, 15 and 30 ppm in rats. Four groups of rats were administered different concentrations of selenium in drinking water for 30 days before irradiation starting from the ablactation which considered as day 0. The results showed that the sodium selenite of 4 pprn and 8 pprn enhance the 30-day survival of irradiated rats at 7 Gy (Co-60 source, whole body irradiation dose rate of 1 Gy-min(-1)) compared to the control group. The mean cumulated probability of survival of rats was 69% +/- 6 (mean +/- S.E.) and 77% +/- 6 in 4 and 8 ppm groups, respectively, versus 42% +/- 9 for control group (P < 0.001). Our data also indicated that sodium selenite with concentrations of 15 and 30 ppm had no significant reduction in mortality. The mean cumulated probability of survival of rats was 50% +/- 12 (P = 0.39) and 49% +/- 14 (P = 0.04), respectively. The toxic effects of selenium were observed at 15 ppm and 30 ppm, survivals after 30 days of selenium intake were 76% and 46%, respectively. We conclude that 4 and 8 ppm sodium selenite have a radio-protective effect. 15 and 30 ppm sodium selenite had no radio-protective effects in rats, this may be due to a synergism of toxicity and radiation effects.