Introduction: The thyroid gland is a vital endocrine gland that regulates metabolism, growth, and development of the human body. Dexamethasone (Dex) is a synthetic glucocorticoid that is used to treat a variety of metabolic and inflammatory diseases, but there are insufficient data on how it can adversely affect the thyroid gland. Curcumin (Cur) is a powerful natural antioxidant with a variety of medical benefits.
Aim of the Work: To demonstrate the histological, immunohistochemical, and biochemical changes induced by dexamethasone in the thyroid gland of adult male albino rat and to investigate the possible protective effect of curcumin.
Material and Methods: Forty male albino rats were randomly divided into 4 groups (10 rats each): the control group, Cur-group, Dex-group, and Dex+Cur group. Dexamethasone was injected subcutaneously three times per week for thirty days at a dose 0.1 mg/kg/day. Curcumin was given orally at a dose 100 mg/kg/daily for the same period. The thyroid tissues were processed for light and transmission electron microscopic studies. Serum levels of triiodothyronine (T3), thyroxine (T4), and thyroid-stimulating hormone (TSH) were assayed.
Results: Dex-group showed vacuolated, multilayered follicular cells, desquamated cells in the follicular lumen, disrupted follicular basement membrane and congested blood vessels. Ultrastructurally, follicular cells showed cytoplasmic vacuolations, destructed mitochondria, dilated rough endoplasmic reticulum, shrunken irregular nuclei and disturbed normal architecture compared to the control group. There was a significant increase in (collagen deposition and Ki67 immunoexpression) and a significant decrease of (serum levels of T3, T4 and TSH) in Dex group versus control group. Co-treatment with curcumin in Dex+Cur-group restored the normal glandular structure and biochemical parameters.
Conclusion: Dexamethasone induced adverse effects on both structure and function of the thyroid gland of adult albino rats that could be ameliorated by co-treatment with curcumin. So, concomitant intake of curcumin with dexamethasone is recommended to protect the thyroid gland.