The effect of melatonin on lipid peroxidation during radiotherapy in female rats

Background: Because radiotherapy is one of the causes of primary or seconda ry ovarian failure, protection of ovarian functions in the patients receivi ng total body or pelvic radiotherapy is of importance. In this study, we in vestigated the role of melatonin in the oxidative damage in both whole body and ovaries, which is caused by radiotherapy. Materials and Methods: Eighteen female rats were divided into 3 groups, eac h of which consisted of 6 rats. First group was control group receiving no treatment, second group received total body radiotherapy (RT) by 2 x 360 cG y only and third group received radiotherapy plus melatonin. Malondialdehyd e (MDA) levels in both blood and ovarian tissue were detected as the indica tor of free radical (FR) damage. Levels of erythrocyte superoxide dismutase (SOD) and glutathion peroxidase (GPX) in blood were measured as the indica tors of antioxidant level. Results: Radiotherapy caused a significant increase in the levels of MDA in blood and ovarian tissue (p < 0.001). However, MDA levels decreased in the radiotherapy plus melatonin group (p < 0.05). SOD and GPX levels decreased insignificantly in the radiotherapy only group while they increased in the radiotherapy plus melatonin group significantly (p < 0.01 and p < 0.05, re spectively). Conclusion: Melatonin, in rats, reduced the level of MDA, which is elevated by radiotherapy and increased the levels of SOD and GPX, which are involve d in the antioxidant system.