Cytogenetic radiation adaptive response assessed by metaphase analysis and micronuclei test in human lymphocytes and mouse bone marrow cells

Radiation adaptive response in human peripheral lymphocytes and mouse bone marrow cells was investigated using both metaphase analysis and micronucleus assay. We assessed the correlation between both tests. Two groups of the human peripheral lymphocytes and mouse bone marrow cells were exposed to low dose (conditioning dose, 0.18 Gy) or high dose (challenging dose, 2 Gy) Υ-rays. The other 4 groups were exposed to low dose followed by high dose after several time intervals (4, 7, 12, and 24 hours, respectively). The frequencies of chromosomal aberrations in metaphase analysis and micronuclei in micronucleus assay were counted. Chromosomal aberrations and micronuclei of preexposed group were lower than those of the group only exposed to high dose radiation. Maximal reduction in frequencies of chromosomal aberrations were observed in the group to which challenging dose was given at 7 hour after a conditioning dose (p<0.001). Metaphase analysis and micronucleus assay revealed very good correlation in both human lymphocytes and mouse bone marrow cells (r=0.98, p<0.001; r=0.99, p=0.001, respectively). Radiation adaptive response could be induced by low dose irradiation in both human lymphocytes and mouse bone marrow cells. There was a significant correlation between metaphase analysis and micronucleus assay