RESUMO
To explore the dose- and time- dependent relationship between the chronic iodine excess and thyroid structure, ultrastructure, and thyroid function in autoimmune-prone NOD. H-2h4 mice. Chronic iodine excess leads to iodine-induced goiter with an ultrastructure of follicle epithelial cells injury in a dose and time dependent way.
RESUMO
Objective To investigate the effect of iodine excess on thyroid follicle epithelial ultrstructure and the relationship between thyroid iniury and autoimmune thyroiditis. Methods NOD.H-2h4 mice and Kunming mice were randomly divided into four groups receiving plain water,5 fold,10 fold,and 100 fold excessive iodine water.4,8 and 24 weeks after receiving iodine water,the mice were killed.After fixation with osmic acid and dual staining with uranyl chloride and citrate lead,thyroid gland ultrstructure was examined with electron microscopy.Resuits Iodine treated NOD.H-2h4 mice exhibited marked accumulation of peroxisome and secondary lysosomes,apoptosis and necrosis of thyroid epithelial cell.damage of thyroid follicles and lymphocvtic infiltration.The observed changes induced by iodine were in a dose dependent way.Conclusion The oxidative iniury on the thyroid epithelial cells induced by iodine excess might be the prerequisite for the creation of autoimmune thyroiditis.
RESUMO
Objective To investigate the kinetic changes of inflammatory cell infiltration and thyroid autoantibodies in the development of iodine-induced autoimmune thyroiditis in NOD.H-2~(h4)mice.Methods Either 128 five-week-old NOD.H-2~(h4)mice or 128 Kunming mice were randomly divided into two groups,and received plain water or water containing 0.05% sodium iodide.At the time points of 1,2,4,8,12,16,and 24 week after receiving iodinated water,mice were anesthetized by diethyl ether and bled from eye socket vein,and their thyroid glands were collected.Indirect ELISA method was used to measure the levels of serum thyroglobulin autoantibodies (TgAb)and thyroid hormone.After being fixed with paraformaldehyde and embedded in paraffin,thyroid sections were stained with HE and used for morphometrieal analysis.Results In the iodine treated group of NOD.H-2~(h4) mice,autoimmune thyroiditis was observed as early as 1 week after they began receiving indinated water.The prevalence as well as the degree of autoimmune thyroiditis reached the maximum at 12 weeks and remained until 24 weeks.Serum TgAb level increased after 8 weeks of iodine ingestion in NOD.H-2~(h4) mice,then increased steadily throughout the 24 weeks of experiment.On the contrary,serum TgAb was not increased in the control group of Kunming mice.Conclusion Iodine may induce and exacerbate lymphocytic infiltration of the thyroid in genetically susceptible NOD.H-2~(h4) mice,and serum TgAb is just a marker of autoimmune thyroiditis.