Melatonin ameliorates ionizing radiation-induced oxidative organ damage in rats


Sener G. , Jahovic N., Tosun O., Atasoy B. M. , Yegen B.

LIFE SCIENCES, cilt.74, ss.563-572, 2003 (SCI İndekslerine Giren Dergi) identifier identifier identifier

  • Cilt numarası: 74 Konu: 5
  • Basım Tarihi: 2003
  • Doi Numarası: 10.1016/j.lfs.2003.05.011
  • Dergi Adı: LIFE SCIENCES
  • Sayfa Sayıları: ss.563-572

Özet

This study was designed to study the effects of the potential radioprotective properties of pharmacological doses of melatonin against organ damage induced by whole-body irradiation (IR) in rats. A total of 32 male Sprague-Dawley rats were exposed to irradiation performed with a LINAC producing 6 MV photons at a focus 100 cm distant from the skin. Under ketamine anaesthesia, each rat received a single whole-body dose of 800 cGy. Immediately before and after IR, rats were treated with either saline or melatonin (20 mg/kg and 10 mg/kg, ip) and decapitated at 12-h after exposure to irradiation. Another group of rats was followed for 72-h after IR, where melatonin (10 mg/kg, ip) injections were repeated once daily. Tissue levels of malondialdehyde (MDA)an index of lipid peroxidation-, glutathione (GSH)-a key to antioxidant- and myeloperoxidase (MPO) activity-an index of neutrophil infiltration-were estimated in liver, lung, colon and intestinal tissues. The results demonstrate that both 12-h and 72-h following IR, tissue leves of MDA were elevated (p<0.05-0.001), while GSH levels were reduced (p<0.05-0.001) in all organs. On the other hand, melatonin, reduced the levels of MDA and increased the GSH levels significantly, (p<0.05-0.001). MPO activity was increased significantly in the colonic tissue at the both 12-h and 72-h, and in the hepatic tissue at the 72-h following IR, which were reduced by melatonin (p<0.01-0.001). In the lung tissue enzyme activity was decreased at 72nd h of postirradiation. In conclusion, the increase in MDA levels and MPO activity and the concomitant decrease in GSH levels demonstrate the role of oxidative mechanisms in irradiation-induced tissue damage, and melatonin, by its free radical scavenging and antioxidant properties, ameliorates irradiation-induced organ injury. Thus, supplementing cancer patients with adjuvant therapy of melatonin may have some benefit for successful radiotherapy. (C) 2003 Elsevier Inc. All rights reserved.