Abstract: Objective To investigate the inhibitory effect of α-lipoic acid on inflammation in autoimmune thyroiditis (AIT) mice and its effect on lymphocyte subsets. Methods Eighty NOD.H-2h 4 female rats were randomly divided into a control group and the AIT group which was given 50 mg/L sodium iodide orally; Low- and high-dose α-lipoic acid intervention group was injected intraperitoneally with 0.1 and 0.4 g/L α-lipoic acid daily. Twenty animals in each group were continued to be intervened for 8 weeks. After 8 weeks of intervention, HE staining was used to observe lymphocyte infiltration; flow cytometry was used to detect Th17, Treg, CD4⁺, CD8⁺ T cells and CD4⁺/CD8⁺ levels; and Western blot method was used to determine p38MAPK and NF-κB protein level. Results The incidence of thyroid inflammation in AIT group was as high as 85%. The incidence of thyroiditis, the degree of thyroid inflammation, and the proportion of Th17 cells in the AIT+low/high-dose alpha-lipoic acid group were significantly lower than those in the AIT group (P＜0.05), and the proportion of Treg, CD4⁺, CD8⁺, and CD4⁺/CD8⁺ cells were significant higher than that in the AIT group (P＜0.05).The AIT+low/high-dose α-lipoic acid group had significantly lower relative protein expression than those in the AIT group (P＜0.05). Conclusions α-lipoic acid can reduce the expression of inflammatory cytokines in autoimmune thyroid mice, improve the proportion of lymphocyte subsets, thereby suppressing the inflammatory response and improving the symptoms of AIT.

Key words: α-lipoic acid, autoimmune thyroiditis, p38 mitogen-activated protein kinase(p38MAPK), NF-κB pathway, T lymphocyte subset