[Tetramethylpyrazine attenuates experimental autoimmune myasthenia gravis in rats via regulating related cytokines and antibodies].

Objective To investigate the effects of tetramethylpyrazine (TMP) on experimental autoimmune myasthenia gravis (EAMG) in rats and explore the possible immune regulation mechanism. Methods Lewis rats were randomly divided into 4 groups: control group, EAMG group, TMP low-dose group (TMP-L, 10 mg/kg) and TMP high-dose group (TMP-H, 20 mg/kg). Except the control group, the other 3 groups were subjected to EAMG modeling. The body mass was determined and the symptoms of muscular weakness in rats were scored by Lennon EAMG criteria. The expressions of acetylcholine receptor (AChR), IgG and C3 in neuromuscular junctions were examined by immunofluorescence. The levels of R97-116 antibody (IgG1, IgG2a, IgG2b), tumor necrosis factor α (TNF-α), interferon γ (IFN-γ) and interleukin 10 (IL-10) were detected by ELISA. Results TMP decreased the scores in the evaluation of the symptoms of muscle weakness in EAMG rats. Moreover, TMP administration significantly inhibited AChR expression and increased IgG and C3 expression in neuromuscular junctions of EAMG rats. In addition, after TMP treament, the levels of IgG1, IgG2a and TNF-α were remarkably reduced, while IL-10 level was elevated. However, there was no significant change in serum levels of IgG2b and IFN-γ. Conclusion TMP can exert inhibitory effects on Th1, Th2 and B cells and modulate the levels of IgG1, IgG2a, TNF-α and IL-10. All these effects contribute to relieve the symptoms of muscle weakness in EAMG rats.