The Influence Of Selenium And Iodine On The Histio-Strcture, Function And Contra-Oxidation Of Thyroid Of Rats

Objective: To investigate the influence of selenium and iodine on the histio-strcture,ultramicrostructure, thyroid hormones, levels of autoantibodies and contra-oxidation of rats.Methods: Wistar rats were divided into six groups by random: the normal control, high iodinegroup, high iodine plus selenium group, experimental autoimmune thyroiditis (EAT)group, seleniumprophylaxis EAT group and selenium curatio-EAT group. Except the normal control, all groups drunkwater containing 0.05% NaI. EAT models were set up by immuning animals with emulsifiedthyroglobulin, and we lavaged rats with sodium selenite at different time in high iodine plus seleniumgroup, selenium prophylaxis EAT group and selenium curatio-EAT group. At the end of ourexperiment, we observed the histio-strcture, ultramicrostructure, thyroid hormones, levels ofautoantibodies and levels of SOD and MDA in tissue bomogenate of thyroid.Results: (1) Compared with the control group, the levels of TGAb and TMAb in the high iodioneand high iodione plus selenium group were almost normal(P＞0.05). The levels were highest in theEAT group(P＜0.05),at the end of the experiment, TGAb and TMAb were much higher than the normalcontrol,(62.07±10.01)%VS(2.97±0.36)%, (51.5±5.91)VS(3.14±0.18)%(P＜0.05). After treatment ofselenium, the levels of autoantibodies were lower, in the selenium prophylaxis EAT group, TGAbwas(40.28±6.91)%, TMAb was (35.02±3.67)%(P＜0.05),in the selenium curatio-EAT group, TGAbwas (42.8±13.9)%, TMAb was(35±5.64)%(P＜0.05). (2)Levels of FT₃ and FT₄ were almost samebetween high iodione group and high iodine plus selenium group, Levels of TSH were almost the samein each group(P＞0.05).At the end of the experiment, FT₃ and FT₄ were much higher than the normalcontrol in the EAT group, selenium prophylaxis EAT group and selenium curatio-EAT group(P＜0.05),FT₄ in selenium curatio-EAT group was lower than the EAT group(P＜0.05). (3) After treatment ofselenium, tissue structure under light microscope and transmission electron microscope were better.(4)Levelsof SOD was higher,and MDA was lower in high iodione plus selenium group than highiodione group. Compared with EAT group, levels of SOD was higher, and MDA was lower inselenium prophylaxis EAT group and selenium curatio-EAT group(P＜0.05).Conclusion: The excessive intake of iodione can destroy the thyroid of rats, but the autoimmuneeffect it causes is weak and slow; Selenium can protect it in a certain extent, and and lighten theautoimmune response of EAT rats. It realizes this maybe by cleansing free radical, and improving theredox state.