[Experimental study on effects of iodine deficiency and excess on thyroid autoimmunity].
OBJECTIVE
To observe the effects of iodine on the level of CD4/CD8 cells and the production of thyroglobulin autoantibody (TGAb) and thyroid peroxidase autoantibody (TPOAb) in Wistar rats and to investigate the role of iodine in thyroid autoimmunity.


METHODS
Rat models with different iodine intakes including low iodine (LI,), normal iodine (NI,), 5 times normal iodine (5HI), 10 times normal iodine (10HI), 50 times normal iodine (50HI) and 100 times normal iodine (100HI) were established. The amount of iodine intake per rat per day in every group was about < 1, 6.15, 30.75, 61.50, 307.50, 615.00 microg separately. The levels of CD4 and CD8 immune cells in peripheral blood were measured by using flow cytometry. Radioimmunoassay (RIA) was used to determine the titers of TGAb and TPOAb in the serum.


RESULTS
In peripheral blood, the level of CD4 cells in LI group was (57.9 +/- 4.3)%, being much higher than in NI group (51.2 +/- 4.9)%. When the level of CD8 cells in 100HI group was (18.4 +/- 3.1)% showing significantly lower than in NI group (26.5 +/- 4.1)%, thus making the ratio of CD4/CD8 cells in the above two groups (LI: 2.4 +/- 0.40 and 100 HI: 2.7 +/- 0.4) higher than in NI group (1.9 +/- 0.3). As comparing with NI group (2099 +/- 220) CPM, the level of TGAb in LI group (1510 +/- 221) CPM was significantly decreased; while in 50HI group (3986 +/- 286) and 100HI group (3550 +/- 378) CPM, the levels of TGAb were both increased, and the levels of TPOAb in 10HI group (2066 +/- 184) CPM and in 50HI group (2141 +/- 163) CPM were both distinctly lower than in NI group (2372 +/- 245) CPM.


CONCLUSIONS
Iodine might exert influence on the level of CD4/CD8, and thus the production of thyroid antibodies might directly or indirectly take part in the process of thyroid autoimmunity. Both low iodine and 100 times normal iodine intakes might activate the immune state on some degrees. The effects of iodine on immune responses of TG and TPO antigen in thyroid autoimmunity might not be completely the same.
Zhao
Shu-jun
SJ
Institute of Endocrinology, Tianjin Medical University, Tianjin 300070, China.
Sun
Fu-jun
FJ
Tian
En-jiang
EJ
Chen
Zu-pei
ZP
D000818:Animals; D001323:Autoantibodies / Q000276:immunology; D015551:Autoimmunity / Q000187:drug effects; D016516:CD4-CD8 Ratio; D062787:Drug Overdose; D007455:Iodine / Q000009:adverse effects* / Q000172:deficiency*; D051381:Rats; D017208:Rats, Wistar; D013961:Thyroid Gland / Q000187:drug effects* / Q000276:immunology*
D001323:Autoantibodies; D007455:Iodine