(−)-Epigallocatechin-3-gallate modulates peripheral immunity in the MPTP-induced mouse model of Parkinson's disease

(−)-Epigallocatechin-3-gallate (EGCG) is the most widely studied catechin in green tea and has been identified to regulate immune function. The objective of the present study was to explore the possible application of EGCG in the treatment of Parkinson's disease (PD) by examining its effects on the peripheral immune system in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mouse model. The results demonstrated that EGCG treatment restored the movement behavior of the mice impaired by MPTP, and protected tyrosine hydroxylase-positive cells in the substantia nigra pars compacta region from MPTP toxicity. Flow cytometric analysis indicated that the ratio of CD3(+)CD4(+) to CD3(+)CD8(+) T lymphocytes in the peripheral blood increased in MPTP-treated mice following treatment with EGCG, and EGCG reduced expression of inflammatory factors tumor necrosis factor-α and interleukin-6 in serum. The present findings indicated that EGCG serves neuroprotective effects in an MPTP-induced PD mice model and may exert this through modulating peripheral immune response.