ABSTRACT
Background: Sodium chlorate [NaClO[3]] is found in drinking water, but it has a toxic effect on thyroid. However, curcumin has a thyroid-stimulating effect
Aim of the work: To study the effect of NaClO[3] on the pituitary-thyroid axis of rats and determine the possible protective role of curcumin
Materials and methods: Thirty rats were divided into three groups of 10 rats each. Group I was the control group. In group II, rats received 0.2 g/l of NaClO[3] in drinking water for 3 weeks. In group III, rats received curcumin [100 mg/kg] 1 week before exposure to NaClO[3] and it was continued for 3 weeks. T3, T4, thyroid-stimulating hormone, and superoxide anion were measured. Sections were subjected to H and E, azan stain, caspase-3, and S-100 immunohistochemical stains
Results: In group II, serum T3 and T4 were significantly decreased whereas thyroid-stimulating hormone and superoxide anion were significantly increased compared with the control group. The thyroid gland showed follicular cell hypertrophy, hyperplasia, decreased colloid, and significantly decreased caspase-3 immunoreactivity compared with the control group. The pituitary gland showed significantly increased basophils and significantly decreased S-100-positive folliculostellate cells compared with the control group. In group III, thyroid function tests were significantly improved compared with group II, but did not reach the control level. Thyroid sections appeared apparently normal, with significantly increased caspase-3 immunoreactivity compared with the control group and group II. The pituitary gland showed basophils that were similar to those of the control group. S-100-positive folliculostellate cells were significantly increased compared with group II, but did not reach the control level
Conclusion: Curcumin can protect the thyroid gland from the adverse effects of NaClO[3] and consequently protects the pituitary gland from negative feedback