The effect of melatonin against oxidative damage during total-body irradiation in rats

Radiat Res. 2003 Aug;160(2):251-5. doi: 10.1667/3034.


Melatonin has been reported to participate in the regulation of a number of important physiological and pathological processes. Melatonin, which is a powerful endogenous antioxidant, may play a role in the prevention of oxidative damage. The aim of this study was to investigate the effect of pretreatment with melatonin (5 mg kg(-1) and 10 mg kg(-1)) on gamma-radiation-induced oxidative damage in plasma and erythrocytes after total-body irradiation with a single dose of 5 Gy. Total-body irradiation resulted in a significant increase in plasma and erythrocyte MDA levels. Melatonin alone increased the levels of SOD and GSH-Px. Erythrocyte and plasma MDA levels in irradiated rats that were pretreated with melatonin (5 or 10 mg kg(-1)) were significantly lower than those in rats that were not pretreated. There was no significant difference between the effects of 5 and 10 mg kg(-1) on plasma MDA activities and CAT activities. However, erythrocyte MDA levels showed a dose-dependent decrease, while GSH-Px activities increased with dose. Our study suggests that melatonin administered prior to irradiation may protect against the damage produced by radiation by the up-regulation of antioxidant enzymes and by scavenging free radicals generated by ionizing radiation.

Publication types

  • Comparative Study

MeSH terms

  • Animals
  • Catalase / blood
  • Catalase / metabolism
  • Dose-Response Relationship, Drug
  • Erythrocytes / drug effects
  • Erythrocytes / radiation effects
  • Glutathione Peroxidase / blood
  • Glutathione Peroxidase / metabolism
  • Male
  • Malondialdehyde / blood
  • Malondialdehyde / metabolism
  • Melatonin / pharmacology*
  • Oxidative Stress / drug effects*
  • Oxidative Stress / radiation effects*
  • Plasma / drug effects
  • Plasma / radiation effects
  • Radiation Tolerance / drug effects
  • Radiation-Sensitizing Agents / pharmacology
  • Rats
  • Superoxide Dismutase / blood
  • Superoxide Dismutase / metabolism
  • Whole-Body Irradiation / methods*


  • Radiation-Sensitizing Agents
  • Malondialdehyde
  • Catalase
  • Glutathione Peroxidase
  • Superoxide Dismutase
  • Melatonin