Comparison of Biochemical and Oxidative Stress Parameters in Hypo and Hyperthyroid Rat Models

Abstract

Background: Thyroid functional disorders are relatively common in the general population. Different factors play a role in the development of thyroid disorders. These factors can be associated with the deterioration of the oxidation state of the body and the induction of oxidative stress. Thyroid hormones play an important role in the oxidation state. Objectives: Regarding the role of oxidative stress in different pathologies and the development of various complications, including thyroid disorders, we aimed to compare the biochemical and oxidative stress parameters in hypo and hyperthyroid rat models. Methods: Twenty-one male Wistar rats were assigned into three groups of control, hypothyroid, and hyperthyroid. Hypothyroidism and hyperthyroidism were inducted with PTU (propylthiouracil) and LTX (levothyroxine), respectively. After five weeks of induction, serum biochemical factors and oxidative stress parameters, such as TAC (total antioxidant capacity), MDA (Malondialdehyde), and the thiol group, were measured in these groups. Results: The means of TAC, MDA and UA (uric acid) in the hyperthyroid group were significantly higher than those in the hypothyroid group (P < 0.01, P < 0.01, P < 0.05) but the mean of thiol in the hypothyroid group was significantly higher than that of the hyperthyroid group (P < 0.01). Also, the mean of TAC level in the hypothyroid group was significantly lower than the control group (P < 0.05) and the mean of thiol group in the hypothyroid group was significantly higher than the control group (P < 0.05), but there was no other significant difference between the groups compared to the control group. Among the biochemical parameters, the mean LDH (lactate dehydrogenase) in the hyperthyroid group also showed a significant difference in comparison to the hypothyroid group (P < 0.05), but there was no significant difference between the groups in the mean of the other biochemical parameters. Conclusions: According to the results of this study, hypothyroidism and hyperthyroidism are associated with a disturbance in the oxidation state of the body, and the use of antioxidants can help improve these diseases, especially in hyperthyroidism, due to enhanced metabolism and production of more free radicals.