Endocrine Abstracts (2009) 20 P149

The influence of radioiodine therapy on some parameters of oxidant/antioxidant balance in patients with toxic nodular goitre

Saeid Abdelrazek1, Franciszek Rogowski1, Anna Zonenberg2, Malgorzata Szelachowska2, Maria Gorska2, Agnieszka Nikolajuk2, Adam Parfienczyk1, Piotr Szumowski1, Malgorzata Frackiel1 & Malgorzata Karolczuk-Zarachowicz2

1Department of Nuclear Medicine, Medical University of Bialystok, Bialystok, Poland; 2Department of Endocrinolog diabetology and internal medicine, Medical University of Bialystok, Bialystok, Poland.

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 toxic nodular goitre.

Material and methods: We studied 40 patients with toxic nodular goitre, (31 female, 9 male), aged 21–65 years. 12 normal adult volunteers (age and sex-matched) were studied as control group. All the patients were in mild hyperthyroidism with serum TSH levels was less than 0.1 mU/l and effective half-life was more than 3 days at the time of treatment. Malignant changes were excluded in all nodules by fine needle aspiration biopsy. In the investigated groups, we evaluate malondialdehyde (MDA) as a marker of oxidative stress, glutathione (GSH) and glutathione peroxidase (GPx) activity as a parameters of antioxidant system before and 6 months after radioiodine therapy. The serum fT4, fT3 and TSH were evaluated before and monthly up to 12 months after RIT. Thyroid ultrasound, and thyroid scan were done after12 months of 131I therapy to assess thyroid volume. The activity dose was calculated by Marinelli’s formula and ranged between 280 and 800 MBq. The absorbed dose ranged between 160 and 300 Gy, and was proportional to thyroid volume.

Results: A Significant increase in MDA level with significant decrease in GPx activities and GSH level were observed in these patients before treatment compared to controls subject. Achievement of euthyroidism after 6 months of radioiodine administration resulted in a significant decrease of MDA level, significant increase of GSH level and in GPx activities. Euthyroidism was achieved in 36 patients and hypothyroidism developed in 4 patients. Thyroid volume reduced to about 46% (average).

Conclusions: Our results confirm the imbalance of the antioxidant/oxidant status in patients with toxic nodular goitre. Radioiodine therapy was more effective to improve these balances.