Oxidative stress plays an important role in hyperthyroidism-induced tissue damage. We aimed to determine whether radioiodine therapy has benefit effect on the oxidant and antioxidant status in patients with Graves Disease.
Material and methods: We studied 30 patients with Graves disease, aged 1848 years. 12 normal adult volunteers were studied as control group. All the patients were treated unsuccessfully by antithyroid drugs. The effective half-life measured by the use of radioiodine uptake (RAIU) after 24 and 48 h was more than 3 days at the time of treatment. Malondialdehyde (MDA) as a marker of oxidative stress, glutathione (GSH) and glutathione peroxidase (GPx) activity as a parameters of antioxidant system, were evaluated in the investigated groups before and 6 months after radioiodine therapy. The serum fT4, fT3, TSH, TSHRAb were evaluated before and monthly up to 12 months after RIT. Thyroid ultrasound, and thyroid scan with thyroid RAIU were done before and after12 months of radioiodine therapy. The activity dose was calculated by Marinellis formula and was ranged between 280 and 600 MBq. The absorbed dose ranged between 120 and 200 Gy, Follow up control was done every 4 weeks.
Results: Hyperthyroidism cause a significant increase in MDA level (P< 0.05), with significant decrease in GPx activities (P< 0.05) and GSH level, compared with controls subject. A significant decrease of MDA level with significant increase of GSH level and GPx activities was observed after 6 months of radioiodine therapy in patients who achieved euthyroidism. In 21 patients euthyroidism was achieved, 5 patients received L-thyroxin replacement therapy due to hypothyroidism, two patients were in subclinical hyperthyroidism, and hyperthyroidim persist in 2 patients. Thyroid volume reduced to about 47% (average).
Conclusions: Our results confirm the imbalance of the antioxidant/oxidant status in patients with Graves disease. Radioiodine therapy was more effective to improve these balances.
Prague, Czech Republic
24 - 28 Apr 2010
European Society of Endocrinology