RESUMO
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.
Assuntos
Antioxidantes/farmacologia , Antitireóideos/efeitos adversos , Hipotireoidismo , Metimazol/efeitos adversos , Estresse Oxidativo/efeitos dos fármacos , Quercetina/farmacologia , Animais , Antitireóideos/farmacologia , Biomarcadores/sangue , Hipotireoidismo/sangue , Hipotireoidismo/induzido quimicamente , Masculino , Metimazol/farmacologia , Ratos , Ratos WistarRESUMO
SUMMARY: All methods to detect experimental loss of bone present technique limitations. The sensitivities of image and histological analyses to detect the effects of teriparatide in rats with bone loss after ovariectomy were evaluated. All methods were qualitatively valid. INTRODUCTION: The standardization of methods to assess bone loss after ovariectomy is crucial to establish the degree of experimental osteoporosis. In general, methods per image or histological techniques are used. To validate these two ways to determine the degree of bone loss in ovariectomized rats, we evaluated the sensitivities of bone densitometry, conventional radiography, and histological analysis of the area occupied by collagen, detecting the effects of teriparatide treatment in the femur of ovariectomized rats with bone loss. METHODS: Wistar rats were divided into three groups: a control group, in which the animals were only subjected to laparotomy; an ovariectomized group, in which bilateral removal of the ovaries was performed; and an ovariectomized + teriparatide group, in which bilateral removal of the ovaries was performed, and the animals were treated with 3 µg/100 g/day of teriparatide. Three months following the ovariectomy, bone densitometry, radiographic densitometry, and histological analysis of the area occupied by collagen fibers were carried out in the femur diaphysis. RESULTS: The bone densitometry revealed 11.2% reduction in femur density; in the conventional radiography, the loss of bone mass was 14.5%, and with the histological analysis, a 40.9% reduction in the area occupied by collagen was detected in the femur diaphysis. CONCLUSIONS: In conclusion, histological analysis could not be quantitatively compared with the methods of bone densitometry and conventional radiography; however, all of these methods were qualitatively valid for assessing the loss of bone stemming from ovariectomy and the therapeutic effect of teriparatide in the prevention of osteoporosis.