THE MICRONUCLEUS ASSAY USING PERIPHERAL-BLOOD RETICULOCYTES FROM X-RAY-EXPOSED MICE

A new 'fluorescence' variant of the micronucleus assay using supravita l staining of peripheral blood reticulocytes with an acridine orange c oated slide was recently developed. In this study the application of t his method to detect a mutagenic response to low-dose exposure of X-ir radiation is reported. The mice were exposed to a single dose of 2.5, 5, 10, 15, 25, and 50 cGy. The induction of micronuclei in peripheral blood reticulocytes was recorded with sampling times of 0, 24, 48, 72, and 96 h after exposure without killing of mice, Dose-dependent effec ts were observed at sampling times of 24-72 h reaching maximum levels at 48 h after X-ray exposure. A highly significant (p < 0.01) increase of the micronucleated reticulocytes was found for doses of 10, 15, 25 , and 50 cGy. Neither the dose of 2.5 nor 5 cGy induced the significan t increase in the incidence of micronucleated reticulocytes compared w ith the respective control group.