Comparative study of the effect of experimentally induced hyperthyroidism and hypothyroidism on the parotid gland in adult male albino rats

Abstract

Introduction: Thyroid dysfunctions are considered one of the most important endocrine disorders. Alterations in the level of thyroid hormones cause various subclinical or clinical manifestations. Salivary glands act as the biological media for food and the first line of defense for oral cavity and teeth. Any alterations in their integrity and activity can affect the patient s health. Aim: This study aimed to compare the possible histo-functional alterations that may occur in the parotid gland structure in an experimentally induced hyperthyroid and hypothyroid state. Materials and Methods: Twenty four adult male rats were divided into three equal groups. Group I: served as euthyroid. Group II (hyperthyroid group): rats received Eltroxine in a dose 600 μg/kg/day via an oral gavage feeding needle for three successive weeks. Group III (hypothyroid group): rats received Neomercazole in a dose of 1.35 mg /kg/day via an oral gavage feeding needle for three successive weeks. At the end of the experiment, all animals were weighed, blood samples were collected then all were sacrificed. The parotid glands were weighed and sampled for histopathological, Immunohistochemical and ultrastructural studies. Results: Examination of parotid sections of treated groups showed histopathological changes in the form of swollen serous acini, vacuolation, dilated duct, changes in secretory granules density, congested blood vessels and cellular infiltration. That is accompanied by significant changes in parotid gland weight, rat’s body weight, mast cell number, Bcl-2 positive cells and serum amylase. Conclusion: It is recommended in cases of thyroid dysfunctions to monitor oral and dental health to follow salivary glands dysfunction.