Protective effect of panaxatriol saponins extracted from Panax notoginseng against MPTP-induced neurotoxicity in vivo

Aim of the study: Panaxatriol saponins (PTS), the main constituents extracted from Panax notoginseng, a Chinese herbal medicine, has been shown to be an effective agent on various diseases. Our previous study has demonstrated that PTS is an inducer of thioredoxin-1 (Trx-1) and has a possible potential as a therapeutic agent for Parkinson's disease (PD). However, the effect of PTS on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neurotoxicity in vivo is unknown. Materials and methods: Using locomotor activity test and traction test, we detected the effect of PTS on MPTP-induced behavioral impairment. Tyrosine hydroxylase, Trx-1, cyclooxygenase-2, pro-caspase-9, pro-caspase-12 and caspase-3 expressions in the anatomical region of substantia nigra pars compacta (SNc) were tested by Western blot. Results: PTS provided neuroprotection against the loss of dopaminergic neurons and behavioral impairment caused by MPTP. MPTP-induced neuronal death in the SNc was suppressed by PTS through increasing Trx-1 expression, suppressing cyclooxygenase-2 over-expression and inhibiting mitochondria-mediated apoptosis. Conclusions: PTS, an inducer of Trx-1, has pluripharmacological properties in the protection against PD including enhancing antioxidant activity, acting as neurotrophic factor, modulating inflammation and inhibiting mitochondria-mediated apoptosis. Crown Copyright (C) 2010 Published by Elsevier Ireland Ltd. All rights reserved.