Effects of modified Haizao Yuhu Decoction in experimental autoimmune thyroiditis rats

Modified Hai-zao Yu-hu decoction as a traditional Chinese medicinal formula has been used to treat inflammation-related thyroid diseases. It could significantly improved thyroid function and decrease expression of TRAIL in thyroid cell. Modified Haizao Yuhu Decoction (MHYD), based on clinical experience, has been used for approximately 500 years and famous for its efficiency in treating thyroid-related diseases. To investigate therapeutic effects of MHYD on thyroid-related autoantibodies and thyroid hormone in experimental autoimmune thyroiditis (EAT) rats, and to provide evidence for the immunomodulatory potential during antigenmediated immunostimulation. Materials and methods:The effect of MHYD was investigated in EAT rats induced by subcutaneous injection of porcine thyroglobulin with Freund's adjuvant (complete and incomplete, CFA and IFA). MHYD was fed to EAT rats daily at a dose of 100mg/kg for 10 weeks. The presence of mononuclear cell infiltration in thyroid tissues were examined to assess the severity of EAT. The levels of serum T3, T4, TgAb and TPOAb were determined by radioimmunoassay and protein expressions of TRAIL were detected by immunohistochemistry. MHYD exhibited a significant protective effects by reversing serum T3, T4, TgAb and TPOAb levels, histopathological changes and TRAIL protein expression of thyroid in EAT model rats. Sargassum fusiforme and Radix Glycyrrhiza in the formulation could be responsible for the immunomodulatory effects of MHYD. These results showed MHYD playing a role as an immunomodulator and TRAIL inhibitor during antigenmediated immunostimulation, may warrant further evaluation as a possible agent for the treatment of Hashimoto's thyroiditis.