Effect of NaI on cytokines secretion in cultured human thyrocytes

Objective To investigate the influence of sodium iodide(NaI) on cytokines (IL-6,IL-8) secretion of human thyrocytes and to study the effect of iodine on the pathogenesis of autoimmune thyroid disease. Methods The human thyroid epithelium cells(TEC) from Graves' disease(GD) patients and para-adenoma normal tissues from thyroid adenoma patients were cultured in the absence or presence of 10 -8-10 -3 mol/L NaI.The contents of cytokines such as IL-6,IL-8 in supernatant of cultured thyrocytes were detected by radioimmune assay (RIA). Results ①A few IL-6,IL-8 were detected in supernatant of normal thyrocytes. IL-6,IL-8 in supernatant of GD thyrocytes increased significantly compared with normal thyrocytes (P0.01). ② When NaI concentration was 10 -8-10 -3 mol/L, the contents of IL-6,IL-8 in supernatant of normal thyrocytes was not significantly different from that of 0 mol/L NaI group (P0.05);TEM showed that normal thyrocytes did not have damaging change. ③ When NaI concentration was 10 -6-10 -3mol/L, the contents of IL-6 in supernatant of GD thyrocytes were significantly higher than that in 0 mol/L NaI group (P0.05). When NaI concentration was 10 -7-10 -3 mol/L the contents of IL-8 in supernatant of GD thyrocytes were significantly higher than in 0 mol/L NaI group (P0.05).When NaI concentration was over 10 -6 mol/L, TEM showed that GD thyrocytes showed damaging changes. Conclusion High concentration of iodine not only results in direct damage of GD thyrocytes,but also increases cytokines (IL-6,IL-8) secretion of normal and GD thyrocytes, especially in GD thyrocytes. High concentration of iodine plays a very important role in the pathogenesis of GD.