Histological study of the effect of potassium dichromate on the thyroid follicular cells of adult male albino rat and the possible protective role of ascorbic acid (vitamin C)

AbstractOccupational exposure to toxic heavy metals renders the industrial workers with various health problems. Many heavy metals act as endocrine disruptors. Chromium salts are commonly used in industries as asbestos brake lining, cement dust and food additives. Thyroid is a metabolically active important endocrine gland. Little is known about the toxic effects of chromium on thyroid. So, the aim of this study was evaluation of the histological changes induced by chromium on thyrocytes and the possible protective role of vitamin C. Forty adult male albino rats were divided into four equal groups: control group, vitamin C treated group, potassium dichromate treated group and the fourth group co treated with potassium dichromate and vitamin C. Potassium dichromate was given intraperitonially for 2 weeks at a dose 2mg/kg daily. Vitamin C was given at a dose 120mg/kg orally daily for the same period. Specimens were processed for light and electron microscopy. Apoptosis was evaluated immunohistochemically. Specimens of potassium dichromate group showed disturbance of the normal architecture of the gland with coalescence and degeneration of thyroid follicles and desquamated cells in its lumen. Disruption of the apical and basal membranes of some thyrocytes, flattened hyperchromatic nuclei, dilated RER and swollen degenerated mitochondria were also noted. Immunohistochemically, there were changes in the immune expression of Bcl2 in the cytoplasm of thyrocytes. Vitamin C supplemented group showed partial improvement of the previous changes. So, potassium dichromate induced structural changes in the thyroid follicular cells that were partially improved by vitamin C supplementation