Yet another fragment of information about the complex relationship between iodine (and iodine compounds) and hypothyroidism.
Chemosphere. 2018 May 3;206:320-329. doi: 10.1016/j.chemosphere.2018.05.015. [Epub ahead of print]
Nitric oxide is involved in the hypothyroidism with significant morphology changes in female Wistar rats induced by chronic exposure to high water iodine from potassium iodate.
Rong S1, Gao Y1, Yang Y1, Shao H1, Okekunle AP2, Lv C1, Du Y1, Sun H1, Jiang Y1, Darko GM1, Sun D3.
Author information
1 Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Harbin 150081, China.
2 Department of Nutrition and Food Hygiene, School of Public Health, Harbin Medical University, Harbin 150081, China.
3 Center for Endemic Disease Control, Chinese Center for Disease Control and Prevention, Harbin Medical University, Harbin 150081, China. Electronic address: sundj415@163.com.
Abstract
Epidemiological studies indicated that chronic exposure to high water iodine is associated with primary hypothyroidism (PH) and subclinical hypothyroidism (SCH). However, the mechanism is not well understood. In this study, we explored whether chronic exposure to high water iodine from potassium iodate (KIO3) can induce hypothyroidism in addition to determining if nitric oxide (NO) is involved in the pathogenesis. 96 female Wistar rats were divided into six groups: control, I1000μg/L, I3000μg/L, I6000μg/L, N-nitro-L-arginine methylester (L-NAME) and L-NAME+I6000μg/L. After 3 months, urine iodine concentration, thyroid hormone, NO and nitric oxide synthase (NOS) serum levels were determined. Additionally, thyroid expression of inducible nitric oxide synthase (iNOS) was also investigated. Thyroid morphology was observed under light microscopy and transmission electron microscope. SCH as indicated by elevated serum thyrotropin (TSH) was induced among rats exposed to 3000 μg/L I-, while rats treated with 6000 μg/L I- presented PH characterized by elevated TSH and lowered total thyroxine in serum. Moreover, serum NO, NOS and iNOS expression in the thyroid were significantly increased in I3000μg/L and I6000μg/L groups. Changes in thyroid function and morphology in the L-NAME+I6000μg/L group were extenuated compared to I6000μg/L group. These findings suggested that chronic exposure to high water iodine from KIO3 likely induces hypothyroidism with significant morphology changes in female Wistar rats and NO appears to be involved in the pathogenesis.
KEYWORDS:
Hypothyroidism; N-nitro-L-arginine methylester; Nitric oxide; Potassium iodate; Rat
PMID: 29754056
DOI: 10.1016/j.chemosphere.2018.05.015
