Abstract: Objective An experimental autoimmune thyroiditis (EAT) model in mice was established to evaluate the proportion and function of regulatory T cells (Tregs) and Th17 cells in the splenocytes from the treatment group with different doses of total glucosides of paeony (TGP) . Methods The EAT model mice were randomly divided into 5 groups: model group, TGP high-dose group, TGP medium-dose group,TGP low-dose group and Tripterygium glycosides group. Real-time PCR was performed to detect the expression of Foxp3 mRNA and ROR?t mRNA in the splenocytes of each group. Flow cytometry was performed to detect the percentage of Treg and Th17 cells in the mice splenocytes of each group. Serum levels of TGF-?1 and IL-17 in each group were measured by ELISA. Serum levels of TGAb in each group were detected by chemiluminescence assay.Results Foxp3 mRNA expression in the mice splenocytes in the medium-dose and the high-dose TGP group were significantly higher than that in the model group(P< 0.05). The percentages of Treg cells in the medium-dose and the high-dose TGP group were significantly higher than that in the model group( P<0.01,P<0.05). The percentages of T cells secreting IL-17 in the low-, medium- and high-dose groups of TGP were significantly lower than that in the model group(P<0.001). Serum levels of TGF-?1 in the TGP medium-dose group and the TGP high-dose group were significantly higher than that in the model group( P<0.01).Serum levels of IL-17 in the TGP medium-dose group and the TGP high-dose group were significantly lower than that in the model group (P<0.01,P<0.05). Serum levels of TGAb in the TGP medium-dose group and the TGP high-dose group were significantly lower than that in the model group (P<0.05). Conclusions TGP can regulate the Treg/Th17 immune balance, which can be beneficial to the prognosis of EAT disease. The TGP medium-dose group and the TGP high-dose group had obvious curative effect.

Key words: Experimental Autoimmune Thyroiditis, Thyroglobulin antibody, Total Glucosides of Paeony, Treg/Th17 immune balance, Tripterygium glycosides