Changes in Free Radical Scavengers and Lipid Peroxide in Thyroid Glands of Various Thyroid Disorders

Abstract

To clarify whether the changes of free radicals and its scavengers are induced by thyroid disorders, we measured levels of free radical scavengers and checked °2 radical generating systems in the human thyroid gland.Thyroid specimens from patients with Graves' disease, follicular adenoma, and papillary and follicular carcinomas contained significantly higher concentrations of xanthine oxidase (XOD) and gluthathione peroxidase (GSH-PX), compared to those in the normal thyroid tissue. Catalase concentration was significantly lower in thyroid specimens from patients with Graves' disease and significantly lower in thyroid specimens from patients with follicular adenoma, compared to those in the normal thyroid tissue. Cu/Zn superoxide dismutase (CuIZn SOD) concentration was significantly lower in the specimens from follicular adenoma and papillary carcinoma and Mn SOD concentration was significantly higher in the specimens from papillary carcinoma than those in the normal thyroid tissue. The lipid peroxide concentration, expressed as malondialdehyde (MDA) concentration, was significantly higher in the specimens from papillary carcinoma than those in the normal thyroid tissue.These findings suggest that the levels of free radicals are increased and are scavenged and catalyzed in the thyroid of Graves' disease, whereas free radicals and lipid peroxide are not completely scavenged in papillary carcinoma tissues, suggesting that these substances affect some role in cell function of thyroid tumors.

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.…”

Oxidative Stress and Antioxidant Status in Hypo- and Hyperthyroidism

“…Decreases in CAT activities were found in brown adipose tissue after T3 or T4 treatment [130] and in liver [11,16], whereas lack of change [120,156,179] and decrease [11] were found in heart.…”

“…Indeed, it was reported that cardiac activity decreased after longterm T4 treatment of both young [11,156] and old [120] rats, increased [118] and remained unchanged [120] after long-term T4 treatment of young rats, and remained unchanged after short-term T3 treatment of young rats [110]. Liver GPX activity was found to decrease after T4 treatment [11], but both increased [16] and remain unchanged [110,199] after T3 treatment.…”

“…Because of its great toxicity, H2O2 synthesis must always remain in adequation with the hormonal synthesis and strictly contained at the apical pole of the cell. Thyrocytes possess various enzymatic systems, such as GPx, catalase, superoxide dismutases, and peroxiredoxins that contribute to limit cellular injuries when H2O2 or other ROS are produced in excess [155,156,157].…”

N-Acetylcysteine and 15 Deoxy-Δ12,14-Prostaglandin J2 Exert a Protective Effect Against Autoimmune Thyroid Destruction in Vivo but Not Against Interleukin-1α/Interferon γ-Induced Inhibitory Effects in Thyrocytes in Vitro

“…When ROS are produced in higher amounts, they are systematically eliminated by potent antioxidant systems such as peroxiredoxins, catalase, and glutathione peroxidases. [1][2][3][4][5] Thus, a basal ROS production, which we define as oxidative load, is required to safeguard thyroid hormone synthesis, as recently demonstrated. 6 Likewise, an harmless oxidative stress (OS) may also be important for cell division during goiter formation when thyrocytes are facing iodine deprivation.…”