Fluorescence of Serum and Urine from Rats Exposed to Mixed Gamma-Neutron Radiations

Fluorescence intensity of serum and urine in rats exposed to mixed gamma-neutron radiations was evaluated for dose-dependent changes. Male Sprague-Dawley rats were exposed to doses in the range from 570 to 30,000 rads. Sera and urines were collected 6, 12, 24, 48, and 72 hours after exposure. Emission spectra of diluted sera and urines were measured with a spectrophotofluorometer, and two peaks in the emission spectra of each were studied. A maximal change in fluorescence intensity of sera at 465 nm with exciting light at 350 nm occurred 24 hours after irradiation. The fluorescence intensity decreased with dose in the range from 570 to 9300 rads. An increase in fluorescence intensity at 360 nm (exciting light, 295 nm) occurred 72 hours after doses of 4700 or 9100 rads, but it was not shown to be dose-dependent. In urine, the fluorescence intensity at 425 nm (exciting light, 345 nm) increased as a function of dose in the range from 1000 to 30,000 rads. The intensity at 400 nm (exciting light, 295) did not change with dose. The results indicate that the changes in fluorescence intensities of sera at 465 nm and of urines at 425 nm from irradiated rats show limited usefulness as biological dosimeters.