Immunomodulatory and neuroprotective effects of ginsenoside Rg1 in the MPTP(1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) -induced mouse model of Parkinson's disease.

Ginsenoside Rg1, one of the biologically active ingredients of ginseng, has been considered to be a candidate neuroprotective drug. The objective of the study was to study the protective effects of Rg1 through the peripheral and central inflammation in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced Parkinson's disease (PD) mouse model. Rg1 treatment protected TH-positive cells in the SNpc region from MPTP toxicity measured with immunofluoresence. The protein expression levels of TH in the SNpc region of MPTP-induced mice following treatment with Rg1 were higher than MPTP-induced mice which were tested with Western blot. The ratio of CD3(+)CD4(+) to CD3(+)CD8(+) T cells and CD4(+)CD25(+)Foxp3(+) regulatory T cells in the blood increased in MPTP-induced mice following treatment with Rg1 which were detected by flow cytometry analysis. Moreover, Rg1 reduced the serum concentrations of proinflammatory cytokines TNF-α, IFN-γ, IL-1β and IL-6 which were tested with enzyme-linked immunosorbent assay (ELISA). In addition, Rg1 inhibited the activation of microglia and reduced the infiltration of CD3(+) T cells into the SNpc region which were measured by immunofluorescence. Our results indicated that Rg1 may represent a promising drug for the treatment of PD via the regulation of the peripheral and central inflammation.