RESUMO
Background: An increasing number of studies suggest that hypothyroidism may lead to hepatorenal toxicity. This study examined whether thymoquinone (TQ), the main active Nigella sativa constituent, could prevent the detrimental influences of hepatorenal toxicity of hypothyroidism during the juvenile period in rats. Methods: The male rats were randomly divided into four groups (n = 7), including control, propylthiouracil (PTU), PTU-TQ 5 mg/kg, and PTU-TQ 10 mg/kg. PTU was dissolved in drinking water at a concentration of 0.05% and administered for six weeks. In the PTU-TQ5 and PTU-TQ10 groups, animals received PTU plus 5 mg/kg and 10 mg/kg of the TQ (i.p.) for six weeks, respectively. The rats were evaluated after TQ treatment by measuring serum markers of liver and kidney function tests as well as oxidative stress biomarkers in liver and kidney tissues. Results: Administration of TQ (5 and 10 mg/kg) decreased oxidative stress damage in liver and kidney tissue in hypothyroidism rats with improvement in activities of antioxidant enzymes and a decrease in MDA in both liver and kidney homogenates. Furthermore, TQ treatment significantly inhibited the elevation of serum biochemical markers of liver and kidney function associated with this hepatorenal toxicity. Conclusion: These results suggest that the protective effect of TQ in hypothyroidism-induced hepatorenal toxicity in rats is attributed to its ability to reduce oxidative stress in hepatic and renal tissues. However, more studies are recommended to investigate the exact mechanism (s) for the effect of TQ on hepatorenal outcomes of hypothyroidism in human subjects.
RESUMO
OBJECTIVES: The objective of this study was to evaluate the effect of vitamin E on the oxidative stress parameters and antioxidant defense enzymes in the heart and aorta of 6-n-propylthiouracil (PTU)-induced hypothyroid rats. METHODS: The animals were divided into 4 experimental groups: Group 1 (Euthyroid) received tap water, Group 2 (Hypothyroid) received 0.05 % of PTU in dissolved in their drinking water, Group 3 (PTU+Vit E) hypothyroid rats treated with vitamin E, and Group 4 (Euthyroid+Vit E). Vitamin E was injected daily (20 mg/kg) to groups 3 and 4 via daily gavage for 6 weeks. Malondialdehyde (MDA) levels, total thiol levels, and the activities of Cu, Zn-superoxide dismutase (SOD) and catalase (CAT) were evaluated in the aortic and cardiac tissues. RESULTS: A significant decrease of thyroxine (T4) serum levels confirmed hypothyroidism in rats, which received PTU. The MDA level increased and total thiol level decreased in the hypothyroid group compared to control group (p<0.001). Th e activities of SOD and CAT significantly decreased in the hypothyroid rats in comparison to the control. Vitamin E treatment resulted in increased levels of total thiol, SOD, and CAT within aortic and cardiac tissues and decreased levels of MDA in comparison with the hypothyroid group (p<0.01-p<0.001). CONCLUSIONS: PTU-induced hypothyroidism resulted in oxidative stress. Chronic administration of vitamin E to hypothyroid rats decreased the oxidative stress markers in the aortic and cardiac tissues.
