Activity of antioxidative enzymes and concentration of malondialdehyde as oxidative status markers in women with newly diagnosed Graves‑Basedow disease and after thiamazole therapy leading to euthyroidism

Introduction. Hyperthyroidism in the course of Graves‑Basedow disease leads to intensification of oxidative processes and increased production of free oxygen radicals. It results in abnormal oxidative status of the organism. Objectives. Aim of this work was to assess the dynamics of oxidative status changes in women with Graves‑Basedow disease before and after treatment with thiamazole. Patients and methods. Studies were carried out in 20 women with newly diagnosed hyperthyroidism in the course of Graves‑Basedow disease and in 15 healthy women. Measurements of activity of antioxidant enzymes – superoxide dismutase (cytosolic copper/zinc isoform – Cu/ZnSOD, mitochondrial manganese isoform – MnSOD and extracellular copper/zinc isoform – EC‑SOD) and glutathione peroxidase (GPx), as well as of malondialdehyde (MDA) concentration were performed twice, i.e. before the treatment and after 3–7 months of thiamazole therapy (euthyroidism). Results. Before the treatment, higher MnSOD plasma activity and lower EC‑SOD activity were observed in women with hyperthyroidism in comparison with the control group, whereas the erythrocyte Cu/ZnSOD activity did not differ between the groups. Besides, women with hyperthyroidism had higher GPx activity in red blood cells. In this group studies have demonstrated higher plasma MDA levels, without any differences between the groups in MDA levels in red blood cells. After thiamazole therapy no differences could be demonstrated in MnSOD, EC‑SOD, Cu/ZnSOD and GPx activities and MDA level between the groups. Conclusions. Women with hyperthyroidism in the course of Graves‑Basedow disease experience abnormal oxidative status of the organism, and induction of euthyroidism after therapy with thiamazole results in resolution of these abnormalities.