title: Micronuclei Assessment of The Radioprotective Effects of Melatonin and Vitamin C in Human Lymphocytes.
abstract: 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.
  
  
  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.
  
  
  CONCLUSIONS
  We conclude that simultaneous administration of melatonin and vitamin C as radioprotector substances before irradiation may reduce genotoxicity caused by x-ray irradiation.
authors.affiliation: Department of Medical Physics, School of Medicine-International Campus, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Aram
authors.initials: A
authors.lastname: Rostami
authors.affiliation: Department of Lab Sciences, School of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran.
authors.forename: Seyed Akbar
authors.initials: SA
authors.lastname: Moosavi
authors.affiliation: Department of Medical Biotechnology, School of Advanced Technology, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Hassan
authors.initials: H
authors.lastname: Dianat Moghadam
authors.affiliation: Department of Radiotherapy, Hospital of Shohada Tajrish, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors.forename: Eftekhar Rajab
authors.initials: ER
authors.lastname: Bolookat
keywords: Lymphocyte; Melatonin; Micronucleus; Radioprotective; Vitamin C