Phenotype of blood lymphocytes in correlation with histological picture in thyroid gland of rats treated with potassium iodide

Abstract

Having in mind the former results which confirmed the functional relationship between the thyroid and the immune system, and the administration of potassium iodide (KI) in the therapy of auto-immune diseases, we considered it of interest to investigate the pathogenesis of KI induced experimental thyroiditis, by studying the morphology of thymus, thyroid gland and spleen, as well as the phenotype of lymphocytes in the thymus and peripheral blood in relation to the expression of CD4 and CD8 molecules. The experiments have been carried out on 30 male Wistar rats, divided in 3 groups. The first group (n=10) received KI (225 μg/g, i.p.), the second group (n=10) received KI (675 μg/g, i.p.), while the third group (n=10) received sodium chloride (0.9%, i.p.). The intensity of histological lesions in the thyroid gland, was statistically significant (p<0.01) in KI treated groups, compared to the controls. KI also significantly decreased rat body mass, and increased masses of thymus and thyroid gland (p<0.05). No statistically significant difference was found in thymocyte and peripheral blood CD4+ and CD8+ subpopulation numbers between the groups. Our experiments suggest that KI, at least in some doses could induce mild lymphocytic thyroiditis in rats, and that this simple, practical and non-expensive model of experimental thyroiditis could be of importance for further research.