Laryngeal effect of experimental postnatal hypothyroidism: do thyroid hormone receptors change?

Abstract

In this study, we aimed to investigate the laryngeal histopathological alterations and thyroid hormone receptors in rats with experimentally-induced postnatal hypothyroidism. In this prospective, randomized study, pregnant Wistar albino rats were followed and newborn 20 Wistar albino rat pups were included in the study. The pups were randomly divided into two groups: In group 1 (methimazole (MMI)-induced hypothyroidism group), the mothers and pups were given MMI added water up to 90th day, as the pups were fed with breast milk for 19 to 22 days. In group 2 (control group), the mothers and pups were fed with MMI-free water up to 90th days. When the pups were 90 days of age, they were decapitated and their larynx was removed. Their larynx was evaluated for edema, inflammation, goblet cells, and thyroid hormone receptors (TR-α, TR-β). Nine larynx samples for group 1 and eight for group 2 were studied. There was a significant difference in inflammation between the groups with slightly lower in the hypothyroidism group (p=0.009). The TR-α, TR-β, and edema were significantly higher in the hypothyroidism group (p=0.002, p=0.029, p=0.029). There was no significant difference in the Goblet cells between the groups (p=0.637). Histopathologically increased laryngeal edema and increased thyroid hormone receptors were found, shedding light on the mechanism of voice changes in hypothyroidism.