Effect of iodine on immune disorder and thyroid function in EAT rats

  Objective   To investigate the effect of high iodine uptake on the changes of thyroids weight, morphology, thyroid hormaone, thyroid stimulating hormone(TSH)and thyroid autoantibodies..

  Methods   Female Wistar rats were divided into four groups: A: normal control, group B: porcine thyroglobulin immunized, group C: iodine water raised, group D: combined with iodine taking and immunization.EAT rat was immunized with PTg 100 ug emulsificated with CFA, then was injected subcutaneously with PTg 100 ug emulsificated with IFA after 2^th wk.Rats in group C and D were raised with 0.05% Nal water.Blood samples were taken at 0, 2, 4, 6, 8^th wk.

  Results   Absolute and relative weight of thyroids in group D were heavier than those in groups A and B, P < 0105.Medium lymphocyte infiltration in thyroid tissue presented in group B, Severe infiltration, proliferation of fibrous tissue and local fulliclar atrophy showed in group D.FT₃ and FT₄ value in group B increased at 8^th wk, but is lower than that in group D, P < 0.01.TgAb and TmAb of group B rose at 2^th wk and reached to the peak at 4^th wk, then descended a little but still higher than that in group(P < 0.01).The autoantibodies in group C stepped up gradually and reached the peak value at 8^th wk.The titer of TgAb and TmAb in group D rose most quickly and lasted for longest time than in other groups.

  Conclusion   Iodine may deteriorate Tg2induced autoimmune thyroiditis, enhance the destruction of thyroid gland and elevate the level of autoantibodies.Excessive iodine intake can worsen worsen experimental autoimmune thyroiditis.