Effect Of Iodine On HLA-DR Antigen Expression In Cultured Human Thyrocytes

Objective To investigate the influence of sodium iodide(Nal) on HLA-DR antigen expression and cytokines (TNF-a, IL-lp,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 thyrocytes obtained from 3 Graves' disease patientsd man 2 women, aged 36. 0±13. lyr) and 4 normal control(2 men 2 women, aged 37. 5±9. Oyr) were cultured in the absence or presence of 10~7 - 10~3 mol/L Nal for 48 hours. The morphological changes of thyrocytes were determined by inverted microscope and electron microscope. The HLA-DR antigen expression in thyrocytes was detected by flow-cytometry. The difference of HLA-DR antigen expression in normal, Graves' disease and iodine-treated thyrocytes was analyzed . The contents of cytokines such as TNF-a, IL-l(3,IL-6, IL-8 in supernatant of cultured thyrocytes were detected by radioimmune assay (RIA). The data were analyzed by paired T test.Results After treated with 1(T5 ,10~3 mol/L Nal for 48 hours, the GD thyrocytes lost normal morphology, from flat-adherent to round-detached. Ultrastructure changes such as decreased microvili, swollen mitochondria, dilated endoplasmic reticulum and accumulation of secondary lysosome were found under electron microscope. The similar changes were found in normal thyrocytes with 10 - 3 mol/L Nal, but less severe. There was no significant difference on HLA-DR antigen expression between normal thyrocytes and negative control (3. 2±0. 6 vs 3. 7 ± 0. 5,P>0. 05). The HLA-DR antigen expression was significantly higher in GD thyrocytes than in normal thyrocytes (21. 3±2. 0 vs 3. 2 ± 0. 6,P<0. 01). There was no significant difference on HLA-DR antigen expression in normal thyrocytes among 0,10~7,10~5,10~3 mol/L Nal groups(P>0. 05). The HLA-DR antigen expression in GD thyrocytes was significantly higher in 10~7 mol/L Nal group than in 0 mol/L Nal group (P<0. 05). Whereas the HLA-DR antigen expression in GD thyrocytes was significantly lower in 10~5,10~J mol/L Nal group than in 0 mol/L Nal group(respectively, P<0. 01). Few IL-l|3,IL-6,IL-8 were detected in su-pernatant of normal thyrocytes. TNF-a, IL-lfi, IL-6, IL-8 in supernatant of GD thyrocytes increased significantly compared with normal thyrocytes (P<0. 01). The contents of IL-l(3,IL-6 in supernatant of normal thyrocytes were significantly higher in 10~3mol/ L Nal group than in 0 mol/L Nal group (P<0. 05). The content of IL-8 in supernatant of normal thyrocytes was significantly higher in 10~5 and 10~3 mol/L Nal group than in 0 mol/L Nal group ?. 05). The contents of TNF-a.IL-6 in supernatant of GD thyrocytes were significantly higher in 10~5 and 10~3 mol/L Nal group than in 0 mol/L Nal group (P<0. 05). The contents of IL-1|3, IL-8 in supernatant of GD thyrocytes were significantly higher in 10~7,10^5 and 10~3 mol/L Nal group than in 0 mol/L Nal group (P<0.05).Conclusion High concentration of iodine induces the thyrocyte ultrastrcture lesion. Iodine has no influence on the HLA-DR antigen expression in normal thyrocytes. Low concentration of iodine increases the HLA-DR antigen expression in GD thyrocytes. High concentration of iodine inhibits the HLA-DR antigen expression in GD thyrocytes. Iodine increases cytokines (TNF-a,IL-l(3,IL-6,IL-8) secretion of human thyrocytes.