Differences of relationships between iodine and some chemical elements in normal thyroid and thyroid benign nodules revealed by short-term neutron activation

Abstract

Thyroid benign nodules (TBN) are the most common lesions of this endocrine gland. The etiology of TBN is not clear. The aim of this exploratory study was to examine differences in the content of of bromine (Br), calcium (Ca), chlorine (Cl), iodine (I), potassium (K), magnesium (Mg), manganese (Mn), and sodium (Na), as well as I/Br, I/Ca, I/Cl, I/K, I/Mg, I/Mn, and I/Na content ratios in tissues of normal thyroid and TBN. Thyroid tissue levels of eight chemical elements (ChEs) were prospectively evaluated in 105 apparently healthy persons and in 79 patients with TBN. Measurements were performed using non-destructive instrumental neutron activation analysis with high resolution spectrometry of gamma-radiations from activated short-lived radionuclides. Tissue samples were divided into two portions. One was used for morphological study while the other was intended for ChEs analysis. It was observed that in TBN the Br, Cl, Mn, and Na mass fraction, as well as the I/Br, I/Cl, I/Mn, and I/Na mass fraction ratios were higher whereas mass fractions of Ca and I and also I/K mass fraction ratio were lower than in normal thyroid. These changes can potentially be used as TBN markers. Furthermore, it was found that the levels of Br, Ca, Cl, K, Mg, Mn, and Na contents in the normal and affected thyroid gland were interconnected and depend on the content of I in thyroid tissue. Because I plays a decisive role in the function of the thyroid gland, the data obtained allow us to conclude that, along with I, such ChEs as Br, Ca, Cl, K, Mg, Mn, and Na, if not directly, then indirectly, are involved in the process of thyroid hormone synthesis.