A histological study on the possible protective effect of selenium against chromium-induced thyrotoxicity in adult male albino rats. Issue 1 (March 2016) - Mohamed, Hala Z.E.
Abstract : Background: Chromium is hazardous for animals and human beings. Hexavalent chromium is highly toxic to life forms because of its carcinogenic, neurotoxic, nephrotoxic, genotoxic, and immunotoxic effects. Selenium is known for its antioxidant role in living systems, and therefore it is considered an essential element for humans and animals. Aim: The present work aims at investigating the possible protective effect of selenium against chromium-induced thyrotoxicity in adult male albino rats. Materials and methods: A total of 120 adult male albino rats were divided into three equal groups. The control group was given a single dose of sterile PBS daily for five consecutive days; the chromium-treated group was given a single dose of potassium dichromate daily for five consecutive days; and the selenium–chromium-treated group was given a single dose of nanoselenium and a single dose of potassium dichromate daily for five consecutive days. The animals of all groups were sacrificed at the same time and their thyroid glands were rapidly dissected out. The specimens of each group were processed for light and electron microscopic, and immunohistochemical studies. They were stained with hematoxylin and eosin, toluidine blue, and inducible nitric oxide synthase for evaluating follicular epithelial cells. Quantitative morphometric, and statistical studies were performed. Results: Manifestations of cytotoxicity were visible on light and electron microscopic studies in chromium-treated thyroid sections in the form of disorganized follicles of varying diameters, with a preponderance of smaller over larger follicles. The follicular epithelial cells appeared to be enlarged and had a vacuolated cytoplasm. In addition, irregular shrunken nuclei were noticed. The thyroid gland of selenium–chromium-treated animals showed a near-normal follicular structure. Conclusion: Administration of selenium in response to an increased risk of exposure to chromium compounds may protect the human body against their harmful effects.