Possible protective role of L-thyroxin on the parotid gland of adult male albino rat in carbimazole induced hypothyroidism: histological, histomorphometry and ultrastructural study

Abstract

This study was carried out to throw more light on the histological, biochemical and immunohistochemical changes in the parotid gland of the adult male albino rat, following oral administration of Carbimazole and possible protective role of Levothyroxine sodium (L-Thyroxin). Fifty-five adult male albino rats (Sprague Dawley) were used. They were divided into four groups and eleven subgroups; five rats each; Animals were sacrificed and parotid specimens were processed for light and electron microscopic examination. Administration of Carbimazole resulted in significant damage in the parotid, which was more obvious with longer duration; most of the serous acini had irregular outlines, widely separated with narrow lumen and cytoplasmic vacuoles. Some acinar cells contained irregular, pyknotic or hyperchromatic nuclei. The interlobular and striated ducts appeared disrupted and dilated with cellular infiltration. Oral administration of L-Thyroxin significantly improves histological changes, expression of B cell lymphocyte (Bcl-2) and decrease collagen in Mallory-stained sections as were confirmed statistically. Induction of L-Thyroxin resulted in significant mitigating effects on damage of parotid gland. The results indicate that thyroid hormones administration causes parotid gland adaptation by augmenting endogenous antioxidants and protects rat parotid gland from oxidative stress associated with carbimazole-induced hypothyroidism and parotid gland atrophy.