Effect of Dietary Selenium on the Survival of Rats Exposed to Chronic Whole Body Irradiation

Rats fed a basal low selenium, vitamin E-adequate diet or the basal diet supplemented with 0.5 ppm selenium as selenomethionine for 6 weeks were exposed to 60Co gamma-irradiation at a dose rate of 9.4 r per hour for 20 hours daily. The preirradiation body weight, blood selenium and liver selenium concentrations averaged 130 g, 0.070 and 0.072 ppm, respectively, for the selenium-depleted rats. Respective values for the supplemented rats were 150 g, 0.585 and 0.940 ppm. No differences in preirradiation hematocrit, erythrocyte concentrations or leukocyte concentrations were observed between the two groups. These indices showed characteristic declines after irradiation with no differences between treatments. The length of survival after irradiation was not related to the selenium content of the tissues.