Protective effects of 2,3,5,4′-tetrahydroxystilbene-2-O-β-d-glucoside in the MPTP-induced mouse model of Parkinson's disease: Involvement of reactive oxygen species-mediated JNK, P38 and mitochondrial pathways

Parkinson's disease (PD) is characterized by the selective death of dopaminergic neurons in the substantia nigra pars compacta. Oxidative stress-induced neuron loss is thought to play a crucial role in the pathogenesis of PD. Previous work from our group suggests that 2,3,5,4′-tetrahydroxystilbene-2-O-β-d-glucoside (TSG), an active component extracted from a traditional Chinese herb, Polygonum multiflorum thunb, can attenuate 1-methyl-4-phenyl pyridium-induced apoptosis in the neuronal cell line PC12, by inhibiting reactive oxygen species generation and modulating c-Jun N-terminal kinases (JNK) activation. Here, we investigated the protective effects of TSG against 1-methyl-4-phenyl-1,2,3,6-tetrahydropypridine (MPTP)-induced loss of tyrosine hydroxylase positive cells in mice and the underlying mechanisms. The results showed that MPTP-induced loss of tyrosine hydroxylase positive cells and reactive oxygen species generation were prevented by TSG in a dose-dependent manner. The reactive oxygen species scavenger N-acetylcysteine could also mitigate reactive oxygen species generation. Moreover, JNK and P38 were activated by MPTP, but extracellular signal-regulated protein kinases phosphorylation did not change after MPTP treatment. TSG at different doses blocked the activation of JNK and P38. The protective effect of TSG was also associated with downregulation of the bax/bcl-2 ratio, reversed the release of cytochrome c and smac, and inhibited the activation of caspase-3, -6, and -9 induced by MPTP. In conclusion, our studies demonstrated that the protective effects of TSG in the MPTP-induced mouse model of PD are involved, at least in part, in controlling reactive oxygen species-mediated JNK, P38, and mitochondrial pathways.