Melatonin reduces lipid peroxidation and nitric oxide during irradiation-induced oxidative injury in the rat liver

• Published in: Journal of pineal research Vol. 34; no. 3; pp. 173 - 177
• Main Authors: Taysi, Seyithan, Koc, Mehmet, Büyükokuroğlu, Mehmet Emin, Altınkaynak, Konca, Şahin, Yaşar Nuri
• Format: Journal Article
• Language: English
• Published: Oxford, UK Munksgaard International Publishers 01.04.2003; Blackwell
• Subjects: Animals; Biological and medical sciences; Dose-Response Relationship, Drug; free radicals; irradiation; lipid peroxidation; Lipid Peroxidation - drug effects; Lipid Peroxidation - radiation effects; Liver - drug effects; Liver - pathology; Liver - radiation effects; Male; Malondialdehyde - analysis; Malondialdehyde - metabolism; Malondialdehyde - radiation effects; Medical sciences; melatonin; Melatonin - pharmacology; Nitric Oxide - analysis; Nitric Oxide - metabolism; Nitric Oxide - radiation effects; oxidative stress; Oxidative Stress - drug effects; Oxidative Stress - radiation effects; Radiation therapy and radiosensitizing agent; Radiation-Protective Agents - pharmacology; Rats; Treatment with physical agents; Treatment. General aspects; Tumors; Melatonin; free radicals; Radioprotector; Rat; Digestive system; Liver; Rodentia; Lipids; Antioxidant; Radiotherapy; lipid peroxidation; Biological activity; irradiation; Vertebrata; Gamma irradiation; Ionizing irradiation; Mammalia; Animal; Nitric oxide; oxidative stress; Pineal hormone; Peroxidation
• ISSN: 0742-3098; 1600-079X
• DOI: 10.1034/j.1600-079X.2003.00024.x

:  Radiation therapy is a popular and useful tool in the treatment of cancer. Melatonin participates in the regulation of a number of important physiological and pathological processes. Melatonin, a powerful endogenous antioxidant, plays a role in the reduction of oxidative damage. Thirty adult rats were divided into five equal groups. On the day of the experiment, groups I and II were injected with 5 or 10 mg/kg melatonin, respectively, while group III received isotonic NaCl solution. Thirty minutes later, groups I, II and III were exposed to 6.0 Gy whole body ionizing radiation in a single fraction. Group IV was injected with 5 mg/kg melatonin but was not irradiated. The final group was reserved as sham treated. Liver malondialdehyde (MDA) and nitric oxide (NOċ) levels were measured in all groups. Whole body irradiation caused a significant increase in liver MDA and NOċ levels. Hepatic MDA and NOċ levels in irradiated rats that were pretreated with melatonin (5 or 10 mg/kg) were significantly decreased. Malondialdehyde and NOċ levels were reduced in a dose‐related manner by melatonin. The data show that melatonin reduces liver damage inflicted by irradiation when given prior to the exposure to ionizing radiation. The radioprotective effect of melatonin is likely achieved by its ability to function as a scavenger for free radicals generated by ionizing radiation.