Changes in Prooxidant/Antioxidant Status
of Hyperthyroid Rats Treated with Selenium

Adela Elena Joantã1, Simona Valeria Clichici1, Gabriela Adriana Filip1, and Sanda Andrei2

1 Department of Physiology, Iuliu Hatieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania
2 Department of Biochemistry, University of Agricultural Sciences and Veterinary Medicine, Cluj-Napoca, Romania

Corresponding author: Dr. Adela Elena Joantã
    Department of Physiology
    Iuliu Hatieganu University of Medicine and Pharmacy
    Str. Emil Isac nr. 13
    400023 Cluj-Napoca, Romania
    Telephone: 0040 745 512428
    Fax number: 0040 264 597257
    E-mail: adelaelena@yahoo.com

CEJOEM 2005, Vol.11. No.2.: 123–129

Key words:
Selenium, oxidative stress, thyroid hormones, liver, myocardium

Abstract:
Natural sources of the well-known antioxidant selenium are wheat seeds, onion, tomato, garlic, cabbage, broccoli, fish, internal organs, eggs, etc. Recent studies have shown the relationship between oxidative stress and thyroid disorders. This study deals with the effects of reactive oxygen species and selenium administration in experimental hyperthyroidism. The experiments were carried out in male Wistar rats divided in three groups: Group I – control, Group II – thyroxin-treated, and Group III – thyroxin- and selenium-treated rats. Oxidative stress markers (lipid peroxides, carbonyl level of proteins) and selenium glutathione peroxidase activity were determined in some target tissues of thyroid hormones: liver, thyroid gland, and myocardium. Lipid peroxides were assessed using thiobarbituric acid (TBA) method, carbonyl proteins with dinitrophenylhidrazine and selenium glutathione peroxidase activity by spectrometry. Lipid peroxides and carbonyl level of proteins were found increased in rats treated with thyroxin and decreased in rats treated with selenium too. Selenium glutathione peroxidase activity was increased in rats that had been given selenium. Our results corroborate the occurrence of oxidative stress due to thyroid hormone excess. Selenium administration led to a decrease of oxidative stress markers in target tissues and to an increase in the level of antioxidants. Therefore, combining selenium with the classic treatment of hyperthyroidism may be recommended.

Received: 27 December 2004
Accepted: 13 June 2005
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