Effect of Algae with Iodine Excess on Thyroid Function in Iodine Deficiency Wistar Rats

Objective:To study the effect of Algae with iodine excess on thyroid function and morphology in iodine deficiency Wistar rats.Methods:Iodine-deficent Wistar rats were divided into 4 groups :model group,pure higher iodine group,the conventional dosage Algae group,3 times of dosage Algae group.Serum thyroid-stimulating hormone(TSH)was measured with solid phase radioimmunoassay(IRMA)and serum total T4(TT4),TT3,reverse T3(rT3)and thyroid TT4 with radioimmunoassay(RIA).Ger-Arsenite colormetric method was used to measure median urinary iodine(MUI).Thyroid morphological changes were observed under optical and electronic microscope,Metamorphic imaging system was used to measure the height of thyrocytes and the areas of thyroid follicular cavities.Results:Giving the processing factor 28 days later,pure higher iodine group and the Algae group serum TSH value was obviously lower than normal group and normal group(both(P0.05),no discrepancies exists among the 3 groups.Pure higher iodine group and the Algae group serum TT3 value was higher than that of the model group and normal group(P 0.05 and P0.01 respectively),3 times of dosage Algae group serum TT3 value was obviously lower than pure higher iodine group(P0.05).Pure higher iodine group and the Algae group serum TT4 value was higher than model group(both P0.001).The conventional dosage Algae group serum TT4 value was lower than the normal group with no significant discrepancy,but pure higher iodine group was markedly lower than normal group,3 times of dosage Algae group was markedly higher than normal group(both P0.05);3 times of dosage Algae group serum TT4 value was higher than the conventional dosage Algae group and pure higher iodine group(both P0.05).Serum rT3 value of pure higher iodine group and 3 times of dosage Algae group was higher than normal group,the conventional dosage Algae group was lower than normal group but without significant discrepancy.Tissue TT3 value and TT4 value were both increased(both P0.05).Conclusion:Compared with iodine excess group,Algae may cause hyperthyroidism in iodine deficiency rats.The more dosage of the Algae,the stronger of the hyperthyroidism.