radioprotective effects of selenium and vitamin-e against 6mv x-rays in human blood lymphocytes by micronucleus assay

background: critical macromolecules of cells such as dna are in exposure to damage of free radicals that induced from the interaction of ionizing radiation with biological systems. selenium and vitamin-e are natural compounds that have been shown to be a direct free radical scavenger. the aim of this study was to investigate the radioprotective effect of selenium and vitamin-e separately and synergistically against genotoxicity induced by 6mv x-rays irradiation in blood lymphocytes.   methods: fifteen volunteers were divided into three groups include a, b and c. these groups were given selenium (800iu), vitamin-e (100mg) and selenium (400iu) + vitamin-e (50mg), respectively. peripheral blood samples were collected from each group before (0hr) and 1, 2 and 3hr after selenium and vitamin-e administration (separately and synergistically). then the blood samples were irradiated to 200cgy of 6mv x-rays. after that lymphocyte samples were cultured with mitogenic stimulation to determine the chromosomal aberrations with micronucleus assay in cytokinesis-blocked binucleated cells.   results: the lymphocytes in the blood samples collected at one hr after ingestion selenium and vitamin-e, exposed in vitro to x-rays exhibited a significant decrease in the incidence of micronuclei, compared with control group at 0hr. the maximum protection and decrease in frequency of micronuclei (50%) were observed at one hr after administration of selenium and vitamin-e synergistically.   conclusion: the data suggest that ingestion of selenium and vitamin-e as a radioprotector substance before exposures may reduce genetic damage caused by x-rays irradiation.