To investigate the effects of fluoride on structure and function of thyroid in rats, 80 SD rats were randomly divided into 4 groups, each for 20 rats. One was control group, the other tree groups were administered 50, 100, and 200mg·L^-1 of sodium fluoride in drinking water, respectively, the experiment lasted 150 days. Thyroid of rats were collected and tissue slices were made, blood of rats were collected, and the level of TSH, FT3, FT4 in serum were determined. The results showed that the fluorostic rat models were successfully established .The number of thyroid follicles and epithelia increased, follicle colloid accumulated, the hyperplasia and enlargement of capillary blood vessels were observed, hyperplastie nodes in thyroid appeared. Compared to control group, the level of serum TSH increased gradually and in the high fluoride group （ 200mg·L^-1 NaF ） significandy increased （P〈0.05）, while the content of serum FT4 significantly decreased in this group. It can be concluded that fluoride can induce colloidal and nodular goiter, and cause abnormal changes of thyroid metabolism function.
Journal of Shanghai Jiaotong University (Agricultural Science)