Effects of Green Tea Polyphenols on Iodide-Induced Autoimmune Thyroiditis In Nonobese Diabetic Mice

Abstract

Because green tea polyphenols (GTPs) possess anti-inflammatory properties and are effective in inhibiting autoimmune diseases in experimental settings, we examined whether GTPs prevented the development of autoimmune thyroiditis in iodide-treated nonobese diabetic (NOD) mice, an animal model of Hashimoto's thyroiditis (HT). Mice were given 0.05% iodide water or iodide water supplemented with 0.2% GTPs for 8 weeks. GTPs administration led to an enhanced production of interleukin-10 by concanavalin A-stimulated splenocytes but did not interfere with thyroiditis development. Serum thyroxine levels were not influenced by GTPs. Our data suggest that administration of GTPs may not be an effective strategy for the prevention of HT.

To reflect human autoimmune thyroiditis, thyroid peroxidase (not thyroglobulin) antibodies should be measured in female (not sex-independent) NOD.H2h4 mice

“…Thus, in mice maintained on iodized water, TgAb levels did not differ between the sexes, nor was there a significant sex difference in the extent of thyroiditis [9,10]. Consequently, although some investigations in NOD.H2 h4 mice focused on males [11] or females [12,13], many studies combined their observations for both sexes (for example [14,15] or reported their findings without providing mouse sex [16], as in one of our own studies [17].…”

“…However, for two reasons, NOD.H2 h4 mice, as presently used, are not an accurate model for human disease for the following reasons:-First, dietary iodide supplementation is generally used with mouse strain because it increases the rapidity of onset and severity of thyroid autoimmunity, assessed by determining TgAb levels and the extent of thyroiditis. However, on this regimen there is no difference between sexes in the development of thyroid autoimmunity [9,10], for which reason later studies on NOD.H2 h4 mice involved either one sex or groups of mixed sex [11][12][13][14][15][16][17]. This apparent absence of sexual dimorphism contrasts with the female predominance of autoimmune thyroiditis in humans.…”

“…However, on this regimen there is no difference between sexes in the development of thyroid autoimmunity [9,10], for which reason later studies on NOD.H2 h4 mice involved either one sex or groups of mixed sex [11][12][13][14][15][16][17]. For Hashimoto's thyroiditis, NOD.H2 h4 mice are the most practical and commonly studied model.…”

“…Of note, these studies did not assess TPOAb, a more important marker than TgAb for autoimmune thyroiditis in humans. Consequently, although some investigations in NOD.H2 h4 mice focused on males [11] or females [12,13], many studies combined their observations for both sexes (for example [14,15] or reported their findings without providing mouse sex [16], as in one of our own studies [17]. With this experimental protocol, sexual dimorphism for thyroid autoimmunity has not been observed in NOD.H2 h4 mice, a major difference with human disease.…”

Effect of emodin on T cell subsets in NOD mice with NaI‑induced experimental autoimmune thyroiditis

“…Certain reports have demonstrated that EAT can be induced in NOD mice by administration of NaI. This condition can also be induced by immunization with human thyroglobulin with Freund's adjuvant in CBA/J mice ( 6 – 9 ). Recently, EAT animal models have frequently been used in the majority of studies in order to simulate CLT and identify the proper mechanism involved in CLT.…”