Effect of Poli I:C in murine model of autoimmune thyroiditis

Hashimotos thyroiditis is one of the most common autoimmune diseases in humans and, similar to other autoimmune diseases, is multifactorial in nature. Moreover, the expression of TLRs has been implicated in the pathogenesis of autoimmune and inflammatory diseases, such as diabetes and insulinitis. The TLRs are a family of at least 10 receptors associated with innate immunity that are present in monocytes, macrophages, and dendritic cells, which recognize highly conserved patterns of the surface of microorganisms, such as LPS, peptidoglycan, and dsRNA and CpG sequences.\n\nThe aim of this study was to evaluate mRNA of the TLR3, TLR9 and cytokines (IFN-beta, TNF and IL-1) in thyroid follicular cells obtained of mice with autoimmune experimental thyroiditis (EAT). For that C57BL/6 mice were immunized with Tg plus complete Freunds adyuvant and treated or not with Poli I:C. Anti-thyroglobulin autoantibodies level was determined by indirect ELISA. Also isolated thyroid follicles were treated in vitro with Poli IC. The results show that TLR3 receptors and some cytokines (IFN-beta, TNF and IL-10) are more highly expressed in thyroid follicular cells treated with Poli I:C. and in the animals with TAE, which present humoral autoimmune response. Taken together, these results suggest that TLR3 expression in thyroid follicular cells induces signaling mechanisms to enhanced IL-1, TNF and IFN-{beta} levels during pathogen infections and that could trigger of autoimmune thyroiditis.