title: The effect of melatonin against oxidative damage during total-body irradiation in rats.
abstract: 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.
authors.affiliation: Department of Radiation Oncology, Ataturk University, Medical School, Erzurum, Turkey. mkoc@atauni.edu.tr
authors.forename: Mehmet
authors.initials: M
authors.lastname: Koc
authors.forename: Seyithan
authors.initials: S
authors.lastname: Taysi
authors.forename: M
authors.initials: M
authors.lastname: Emin Buyukokuroglu
authors.forename: Nuri
authors.initials: N
authors.lastname: Bakan
mesh_terms: D000818:Animals; D002374:Catalase / Q000097:blood / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004912:Erythrocytes / Q000187:drug effects / Q000528:radiation effects; D005979:Glutathione Peroxidase / Q000097:blood / Q000378:metabolism; D008297:Male; D008315:Malondialdehyde / Q000097:blood / Q000378:metabolism; D008550:Melatonin / Q000494:pharmacology*; D018384:Oxidative Stress / Q000187:drug effects* / Q000528:radiation effects*; D010949:Plasma / Q000187:drug effects / Q000528:radiation effects; D011836:Radiation Tolerance / Q000187:drug effects; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology; D051381:Rats; D013482:Superoxide Dismutase / Q000097:blood / Q000378:metabolism; D014916:Whole-Body Irradiation / Q000379:methods*
chemical_list: D011838:Radiation-Sensitizing Agents; D008315:Malondialdehyde; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D008550:Melatonin