title: Radioprotective effect of melatonin in reducing oxidative stress in rat lenses.
abstract: OBJECTIVE
  Ocular morbidity is widely observed when radiotherapy includes the orbit. Oxidative stress generated by irradiation is responsible for this complication. In different studies, it has been shown that melatonin has antioxidative properties and a radioprotective role. The aim of this study was to evaluate the antioxidant role of melatonin against radiation-induced oxidative injury in rats' lenses after total cranial irradiation.
  
  
  METHODS
  Thirty-six adult female Sprague-Dawley rats were divided into six groups. Group I was the control group, group II only received total cranial gamma irradiation of 5 Gy, group III was exposed as the second group but at the dose of 8 Gy, group IV received 30 mg/kg melatonin 30 minutes prior to radiation plus total cranial irradiation of 5 Gy plus 5 mg/kg melatonin daily through intraperitoneal injection for ten days after irradiation, group V was treated similar to the fourth group, i.e. received irradiation plus melatonin, but at the dose of 8 Gy, and group VI only received melatonin (30 mg/kg on the first day and 5 mg/kg on the following days). Ten days after irradiation, all rats were sacrificed and their eyes were enucleated to measure the biochemical parameters i.e. malondialdehyde (MDA) and glutathione (GSH).
  
  
  RESULTS
  The levels of MDA in rat lenses increased and the levels of glutathione in lenses decreased after gamma ray irradiation but these parameters were still within normal limits in rats that received melatonin.
  
  
  CONCLUSIONS
  It could be concluded that melatonin is useful in preventing radiation-induced oxidative injury due to its antioxidative and free radical scavenging properties.
authors.affiliation: 1. Medical Physics Department, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Shirazi
authors.forename: Gholam Hasan
authors.initials: GH
authors.lastname: Haddadi
authors.forename: Fahimeh
authors.initials: F
authors.lastname: Asadi-Amoli
authors.forename: Saeideh
authors.initials: S
authors.lastname: Sakhaee
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Ghazi-Khansari
authors.forename: Abolghasem
authors.initials: A
authors.lastname: Avand
keywords: Cataract; Free Radicals; Melatonin; Radiation; Radioprotector