Parkinson's disease (PD) is pathologically characterized by the progressive loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc) and the accumulation of aggregated α-synuclein in specific central nervous system (CNS) regions. Disease development is attributed to α-synuclein abnormalities, particularly aggregation and phosphorylation. The ginsenoside Rg1, an active component of ginseng, possesses neuroprotective and anti-inflammatory effects. The purpose of the present study was to evaluate these activities of Rg1 in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)/probenecid (MPTP/p)-induced PD mouse model for the first time and to elucidate the underlying mechanisms. Oral treatment with Rg1 significantly attenuated the high MPTP-induced mortality, behavior defects, loss of dopamine neurons and abnormal ultrastructure changes in the SNpc. Other assays indicated that the protective effect of Rg1 may be mediated by its anti-neuroinflammatory properties. Rg1 regulated MPTP-induced reactive astrocytes and microglia and decreased the release of cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in the SNpc. Rg1 also alleviated the unusual MPTP-induced increase in oligomeric, phosphorylated and disease-related α-synuclein in the SNpc. In conclusion, Rg1 protects dopaminergic neurons, most likely by reducing aberrant α-synuclein-mediated neuroinflammation, and holds promise for PD therapeutics.
Keywords: 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine; Ginsenoside Rg1; Neuroinflammation; Parkinson’; s disease; α-Synuclein.
Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.