Turkish Journal of Medical Sciences




Aims: To investigate radiation-induced oxidative damage in erythrocytes after administration of radioiodine-131 (^{131}I) in patients with hyperthyroidism. Materials and Methods: Twenty patients with hyperthyroidism (11 F, 9 M) treated with ^{131}I were included into the study. Blood samples were taken from patients just before, 1 hour after and 3 hours after applying radioiodine. Malondialdehyde (MDA) and levels of antioxidant enzymes such as glutathione peroxidase (GPX), superoxide dismutase (SOD) and catalase (CAT) were measured to evaluate the radiation-induced oxidative damage. Results: We found that enzyme activities of SOD, GPX and CAT were decreased 1 hour and 3 hours after radioiodine treatment (P < 0.05), while MDA levels were increased 1 hour and 3 hours after the radioiodine treatment (P < 0.05). Conclusions: Ionizing radiation causes harmful effects through the generation of free radicals. We found that radiation caused an oxidative damage in erythrocytes after administration of ^{131}I in patients with hyperthyroidism. In conclusion, although the population of the study was too small, these results indicate that exposure of hyperthyroid patients to ^{131}I decreased the erythrocyte antioxidant levels and increased MDA levels.


Radioiodine treatment, hyperthyroidism, free radicals

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