Biological Trace Element Research

, Volume 170, Issue 2, pp 382–389 | Cite as

Effects of Excess Fluoride and Iodide on Thyroid Function and Morphology

  • Yaqiu Jiang
  • Xiujuan Guo
  • Qiuyan Sun
  • Zhongyan Shan
  • Weiping TengEmail author


Exposure to high levels of iodide in Cangzhou, Shandong Province, China has been associated with increased incidence of thyroid disease; however, whether fluoride can affect the thyroid remains controversial. To investigate the effects of excess fluoride, we evaluated thyroid gland structure and function in rats exposed to fluoride and iodide, either alone or in combination. Five-week-old Wistar rats (n = 160 total) were randomly divided into eight groups: three groups that were given excess fluoride (15, 30, or 60 ppm F); one group given excess iodide (1200 μg/L I); three groups given excess iodide plus fluoride (1200 μg/L I plus 15, 30, or 60 ppm F); and one control group. The serum concentrations of the thyroid hormones TT3 and TT4 on day 150 were significantly reduced for certain fluoride groups; however, no significant differences were observed in concentrations for the pituitary hormone TSH among any groups. Hematoxylin and eosin staining revealed that iodide causes an increase in the areas of the colloid lumens and a decrease in the diameters of epithelial cells and nuclei; however, fluoride causes an increase in nuclear diameters. The damage to follicular epithelial cells upon fluoride or iodide treatment was easily observed by transmission electron microscopy, but the effects were most dramatic upon treatment with both fluoride and iodide. These results suggest that iodide causes the most damage but that fluoride can promote specific changes in the function and morphology of the thyroid, either alone or in combination with iodide.


Fluoride excess Iodide excess Thyroid Function Morphology 



The authors thank Chenling Fan and Hong Wang for the excellent technical assistance. They would also like to thank all colleagues and students who contributed to this study. It would not have been possible without their help. The research was supported by Dr. Weiping Teng’s scientific research funds.

Conflict of Interest

All authors declare there is no actual or potential interest with other people or organizations within the 3 years of beginning this work.


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Copyright information

© Springer Science+Business Media New York 2015

Authors and Affiliations

  • Yaqiu Jiang
    • 1
  • Xiujuan Guo
    • 1
  • Qiuyan Sun
    • 1
  • Zhongyan Shan
    • 1
  • Weiping Teng
    • 1
    Email author
  1. 1.Department of Endocrinology and Metabolism, Institute of Endocrinology, Liaoning Provincial Key Laboratory of Endocrine DiseasesThe First Affiliated Hospital of China Medical UniversityShenyangPeople’s Republic of China

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