The Usefulness of Two-colour Fluorescence in situ Hybridization Technique Using Chromosomal Subset at Metaphase and Interphase Stage in Radiation Biodosimetry

Peripheral bloods from healthy donors were irradiated by ⁶⁰Co γ-rays and californium (²⁵²Cf) -neutron for 0.5 to 4 Gy and the frequencies of the translocations were detected by two colour fluorescence in situ hybridization (FISH). Chromosomes 1, 2 and 3 and chromosomes 6, 7 and 9 were labeled by rodamine-dUTP and fluorescein-dUTP as viewing red or green signal on metaphase chromosomes, respectively. In separate observation, translocation was detected on the interphase cells by the two color FISH method using whole chromosome painting probes of chromosomes 4 and 9. Detected translocations on the metaphase and interphase cells showed clear dose response relationships. Translocations induced by ⁶⁰Co γ -rays, ²⁵²Cf neutrons, and those in atomic bomb survivors were able to detect easily by both interphase FISH and metaphase FISH using two colour of chromosome subsets. These results suggest that scoring of translocations by two colour FISH of chromosome subsets can serve as more sensitive and applicable biological dosimeter for short or long-term radiation effects.