title: Radioprotective effect of melatonin on radiation-induced lung injury and lipid peroxidation in rats.
abstract: OBJECTIVE
  Free radicals generated by ionizing radiation attack various cellular components such as lipids. The lung is a very radiosensitive organ and its damage is a doselimiting factor in radiotherapy treatments. Melatonin (MLT), the major product of the pineal gland acts as a radioprotective agent. This study aims to investigate the radioprotective effects of MLT on malondialdehyde (MDA) levels and histopathological changes in irradiated lungs.
  
  
  METHODS
  In this experimental study, a total of 62 rats were divided into five groups. Group 1 received no MLT and radiation (unT), group 2 received oral MLT (oM), group 3 received oral MLT and their thoracic areas were irradiated with 18 Gy (oMR), group 4 received MLT by intraperitoneal (i.p.) injection and their thoracic areas were irradiated with 18 Gy (ipM-R), group 5 received only 18 Gy radiation in the thoracic area (R). Following radiotherapy, half of the animals in each group were sacrificed at 48 hours for evaluation of lipid peroxidation and early phase lung injuries. Other animals were sacrificed in the eighth week of the experiment for evaluation of the presence of late phase radiation induced lung injuries.
  
  
  RESULTS
  Pre-treatment of rats with either i.p injection (p<0.05) and oral administration of MLT (p<0.001) significantly reduced MDA levels in red blood cell (RBC) samples compared to the R group. Furthermore, i.p. injection of MLT decreased MDA levels in plasma and tissue (p<0.05). In the early phase of lung injury, both administration of MLT significantly increased lymphocyte (p<0.05) and macrophage frequency (p<0.001). MLT reduced the lung injury index in the lungs compared to the R group (p<0.05).
  
  
  CONCLUSIONS
  The result of this study confirms the radioprotective effect of MLT on lipid peroxidation, and in both early and late phases of radiation induced lung injuries in an animal model.
authors: Department of Biophysics and Biochemistry, Cellular and Molecular Biology Research Centre, Babol University of Medical Sciences, Babol, Iran.
authors: Raziyeh
authors: R
authors: Tahamtan
authors: Department of Biophysics and Biochemistry, Cellular and Molecular Biology Research Centre, Babol University of Medical Sciences, Babol, Iran.
authors: Ali
authors: A
authors: Shabestani Monfared
authors: Department of Stem Cells and Developmental Biology at Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran.
authors: Yasser
authors: Y
authors: Tahamtani
authors: Department of Pathology, Fasa University of Medical Sciences, Fasa, Iran.
authors: Alireza
authors: A
authors: Tavassoli
authors: Department of Biochemistry, Faculty of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
authors: Maasoomeh
authors: M
authors: Akmali
authors: Department of Radiotherapy, Physics Unit, Namazi Hospital, Shiraz University of Medical Sciences, Shiraz, Iran.
authors: Mohammad Amin
authors: MA
authors: Mosleh-Shirazi
authors: Department of Biostatistics, Fasa University of Medical Sciences, Fasa, Iran.
authors: Mohammad Mehdi
authors: MM
authors: Naghizadeh
authors: Student Research Committee, Shiraz University of Medical Sciences, Shiraz, Iran.
authors: Danial
authors: D
authors: Ghasemi
authors: Young Researchers and Elite Club, Shiraz Branch, Islamic Azad University of Shiraz, Shiraz Iran.
authors: Mojtaba
authors: M
authors: Keshavarz
authors: Department of Medical Physics, Fasa University of Medical Sciences, Fasa, Iran.
authors: Gholam Hassan
authors: GH
authors: Haddadi
keywords: Melatonin; Pulmonary Fibrosis; Radiation