Ginsenoside Rd Protects SH-SY5Y Cells against 1-Methyl-4-phenylpyridinium Induced Injury

Ginsenoside Rd (GSRd), one of the main active monomer compounds from the medical plant Panax ginseng, has been shown to promote neuronal survival in models of ischemic cerebral damage. As an extending study, here we examined whether GSRd could exert a beneficial effect in an experimental Parkinson disease (PD) model in vitro, in which SH-SY5Y cells were injured by 1-methyl-4-phenylpyridinium (MPP⁺), an active metabolic product of the classical Parkinsonian toxin1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Our results, from the addition of different concentrations of GSRd (1, 10 and 50 μM), showed that GSRd at 1 and 10 μM could significantly attenuate MPP⁺-induced cell death. This protective effect may be ascribed to its ability to reduce intracellular reactive oxygen species levels, enhance antioxidant enzymatic activities, preserve the activity of respiratory complex I, stabilize the mitochondrial membrane potential and increase intracellular ATP levels. Additionally, the PI3K/Akt survival-signaling pathway was also involved in the protective effect of GSRd. Finally, using a mouse PD model in vivo, we also found that GSRd obviously reversed the loss of tyrosine hydroxylase-positive cells in substanitia nigra induced by MPTP. Thus, our findings demonstrated that GSRd showed a significant neuro-protective effect against experimental PD models, which may involve its antioxidant effects and mitochondrial function preservation.