Oxidative damage and antioxidant enzyme activities in experimental hypothyroidism

Abstract

Free radicals are now well known to damage cellular components. To investigate whether age and thyroid level affect peroxidation speed, we examined the levels of malondialdehyde and antioxidant enzyme activities in different age groups of hypothyroid rats. Hypothyroidism was induced in 30- and 60-day-old Wistar Albino rats by the i.p. administration of propylthiouracil (10 mg kg(-1) body weight) for 15 days. While malondialdehyde levels of 30- or 60-day-old hypothyroid rats were increased in liver, they were decreased in the tissues of the heart and thyroid. While glucose-6-phosphate dehydrogenase activity levels did not change in heart, brain and liver tissues of 30-day-old rats, they increased in brain and heart tissues of 60-day-old experimental groups, but decreased in the liver. Catalase activities decreased in the liver and heart of rats with hypothyroidism, but increased in erythrocytes. In control groups while malondialdehyde levels increased in brain, heart and thymus with regard to age, they decreased in plasma. Glucose-6-phosphate dehydrogenase and catalase activities were not affected by age in tissues of the thymus, thyroid and brain, but they were decreased in the heart tissue. The changes in the levels of lipid peroxidation and antioxidant enzyme activities which were determined in different tissues of hypothyroid rats indicate a cause for functional disorder of these tissues. Moreover, there may be changes depending on age at lipid peroxidation and antioxidant enzyme activity levels.

Evaluation of Oxidative Stress Status and Adenosine Deaminase Activity in Hyperthyroid and Hypothyroid Patients

“…Plasma MDA levels with hyperthyroidism prior to treatment to be significantly higher than control group, with the levels decreasing after treatment [20]. Consistent with other studies [21,22], in our study MDA levels were higher in patients with hyperthyroidisms compared to control group ( heart, hepatic and brain tissue [23,24]. It is known that lipid peroxidation and generation of ROS leads to oxidative stress and damage.…”

Regulation of oxidative stress and lipid peroxidation in PTU induced mice, treated with Pyrroloquinoline quinone (PQQ)

“…Thyroid abnormalities are also considered as physiological modulators of in vivo cellular oxidative stress. It is now well established that deficiency of thyroid hormones can lead to an oxidative stress condition in the liver and heart with a consequent lipid peroxidative response (Yilmaz et al, 2003). Further, hypothyroidism-induced dysfunction of the respiratory chain in the mitochondria leads to accelerated production of free radicals (i.e., superoxide anion, hydrogen peroxide, and hydroxyl radical as well as lipid peroxides), which consequently leads to oxidative stress (Venditti et al, 1997;Yilmaz et al, 2003;Carmeli et al, 2008).…”

Comparison of therapeutic effects of L-Thyroxin, apelin and a combination of both on antioxidant enzymes in the heart of PTU-induced hypothyroid rats

“…Another study showed that lipid peroxidation increase and an antioxidant level decrease in blood of hypothyroid patients (Dumitriu et al 1988). Moreover, it has been demonstrated that the MDA content in plasma, liver and muscle of hypothyroid patients is increased (Yilmaz et al 2003). Also, another finding has shown an increasing of lipid peroxidation in plasma, liver, heart, and muscle of PTU-induced hypothyroid rats.…”