Effects of Quercetin on Oxidative Stress Biomarkers in Methimazole – Induced Hypothyroid Rats

Abstract

The objective of the present study was to evaluate the effect of quercetin on oxidative stress biomarkers in methimazole (MMI) - induced hypothyroidism male rats. Hypothyroidism was induced by administering MMI at 20 mg/100 ml in the drinking water, for 1 month. After achieved hypothyroidism, rats received orally 10 or 25 mg/kg of quercetin (QT) for 8 weeks. 60 male wistar rats were randomly divided into 6 groups (group I, control; group II, QT10; group III, QT25; group IV, hypothyroid; group V, hypothyroid+QT10; group VI, hypothyroid+QT25). Liver, kidney and serum TBARS levels significantly increased in hypothyroid rats when compared to controls, along with increased protein carbonyl (PCO) in liver and increased ROS levels in liver and kidney tissues. QT10 and QT25 were effective in decreasing TBARS levels in serum and kidney, PCO levels in liver and ROS generation in liver and kidney. MMI - induced hypothyroidism also increased TBARS levels in cerebral cortex and hippocampus that in turn were decreased in rats treated with QT25. Moreover, the administration of QT25 to hypothyroid rats resulted in decreased SOD activities in liver and whole blood and increased liver CAT activity. Liver and kidney ascorbic acid levels were restored with quercetin supplementation at both concentrations. QT10 and QT25 also significantly increased total oxidative scavenging capacity in liver and kidney tissues from hypothyroid rats. These findings suggest that MMI - induced hypothyroidism increases oxidative stress parameters and quercetin administration could exert beneficial effects against redox imbalance in hypothyroid status.

Ameliorating effect of postweaning exposure to antioxidant on disruption of hippocampal neurogenesis induced by developmental hypothyroidism in rats

“…However, little is known about redox status after the cessation of developmental exposure to antithyroid agent. In adult rats, increase of oxidative stress in the brain sustains for at least 8 weeks after achieving hypothyroidism for 4 weeks by exposure to anti-thyroid agent (Santi et al, 2014). In the present study, we observed transcript upregulation of antioxidant enzyme genes, Gpx1, Gpx4, Gsta5, Nqo1, Prdx1 and Txn1, in the dentate gyrus at the adult stage after developmental hypothyroidism.…”

Adipokine expression and endothelial function in subclinical hypothyroidism rats

“…We established a model of sHT in rats by gavage with MMI and treated one group of sHT rats with LT 4 . The dosages of MMI and LT 4 were based on former studies ( 24 , 25 ), and different doses of MMI have been verified and adjusted to establish a rat model of sHT in a 4-month experiment. We determined TSH and T 4 levels to confirm that the sHT rat model was successful and that LT 4 treatment was effective.…”

“…After one week of environmental adaptation, rats were randomly divided into five groups: control euthyroid group ( n = 10), sHT A group ( n = 15), sHT B group ( n = 15), sHT C group ( n = 15) and sHT + T 4 group ( n = 10). In the sHT rats, groups A–C were separately induced by administration of 20 mg/kg/day methimazole (MMI), 30 mg/kg/day MMI and 40 mg/kg/day MMI once daily by gavage ( 13 , 23 , 24 ). The sHT + T 4 group was administered 20 mg/kg/day MMI once daily by gavage.…”

Endothelial Functioning and Hemodynamic Parameters in Rats with Subclinical Hypothyroid and the Effects of Thyroxine Replacement

“…SCH rats were induced by MMI administration (10 mg/kg) once daily by gavage. This dose was selected based on previous studies[ 30 – 32 ], and we reduced the dose by five-fold. After 45 days, a rat model of SCH was established.…”