micronuclei assessment of the radioprotective effects of melatonin and vitamin c in human lymphocytes

objective: critical macromolecules such as dna maybe damaged by free radicals that are generated from the interaction of ionizing radiation with biological systems. melatonin and vitamin c have been shown to be direct free radical scavengers. the aim of this study was to investigate the in vivo/in vitro radioprotective effects of melatonin and vitamin c separately and combined against genotoxicity induced by 6 mv x-ray irradiation in human cultured blood lymphocytes. materials and methods: in this experimental study, fifteen volunteers were divided into three groups of melatonin, vitamin c and melatonin plus vitamin c treatment. peripheral blood samples were collected from each group before, and 1, 2 and 3 hours after melatonin and vitamin c administration (separately and combined). the blood samples were then irradiated with 200 cgy of 6 mv x-ray. in order to characterize chromosomal aberrations, the lymphocyte samples were cultured with mitogenic stimulus on cytokinesisblocked binucleated cells. results: the samples collected 1hour after melatonin and vitamin c (separately and combined) ingestion exhibited a significant decrease in the incidence of micronuclei compared with their control group (p<0.05). the maximum synergic protection and reduction in frequency of micronuclei (57%) was observed 1 hour after vitamin c and melatonin administration combined. conclusion: we conclude that simultaneous administration of melatonin and vitamin c as radioprotector substances before irradiation may reduce genotoxicity caused by x-ray irradiation.