The comparison of erythrocyte, plasma, and serum antioxidant activities in toxic multinodular goitre patients before and after surgery

Abstract

Purpose: Thyroid hormones enhance the metabolic rate and antioxidant metabolism by increasing the specific mitochondreal enzymes. It has been shown that due to the oxidative stress, components of the antioxidant system in erythrocytes increased in untreated toxic multinodular goitre patients and return to normal levels by using antithyroid drugs. However, it has not been shown that how L-thyroxine replacement therapy after total thyroidectomy effects these changes. Our aim was to compare the antioxidant levels in toxic multinodular goitre patients just before and 3-months after total thyroidectomy.

Methods: Erythrocyte, plasma, and serum antioxidant activities (glucose-6-phosphate dehydrogenase, catalase, superoxide dismutase, nitric oxide, glutathione reductase, glutathione peroxidase, ceruloplasmin, malonyldialdehyde, vitamin E and vitamin C) were studied in 13 toxic multinodular goitre patients just before and 3 months after surgery. All the patients were euthyroid when the blood samples were collected. Euthyroidism was sustained with antithyroid drugs before operation and with L-thyroxine replacement therapy after total thyroidectomy. Statistical significance was assessed by Mann-Whitney U-test.

Results: The findings showed that there is no significant difference between the erythrocyte, serum and plasma antioxidant enzyme activities, ceruloplasmin, serum tocopherol and, plasma vitamin C levels when the patients were euthyroid either with antithyroid drugs just before surgery or with L-thyroxine replacement therapy 3 months after total thyroidectomy.

Conclusions: L-thyroxine replacement therapy after total thyroidectomy in toxic multinodular goitre patients does not affect the erythrocyte, plasma, and serum antioxidant activities, serum tocopherol and plasma vitamin C levels.