Effects of the root bark of Paeonia suffruticosa on mitochondria-mediated neuroprotection in an MPTP-induced model of Parkinson's disease.

Parkinson's disease (PD) is generally characterized by the progressive loss of dopaminergic neurons projecting from the substantia nigra pars compacta (SNpc) to the striatum that results in movement dysfunction, but also entails mitochondrial dysfunction. The purpose of this study is to evaluate the protective effects of Moutan Cortex Radicis (MCE, Moutan peony) on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD-like symptoms and to elucidate the underlying mechanisms of action, with a focus on mitochondrial function. In a rat primary mesencephalic culture system, MCE significantly protected dopaminergic neurons from the neurotoxic effects of 1-methyl-4-phenylpyridinium (MPP(+)), an active form of MPTP. Additionally, in a subacute mouse model of MPTP-induced PD, MCE resulted in enhanced recovery from PD-like motor symptoms, including increased locomotor activity and reduced bradykinesia. MCE increased dopamine availability and protected against MPTP-induced dopaminergic neuronal damage. Moreover, MCE inhibited MPTP-induced mitochondrial dysfunction and resulted in increased expression of phosphorylated Akt, ND9, mitochondrial transcription factor A, and H2AX in the SNpc. Mitochondria-mediated apoptosis was also inhibited, via the regulation of B-cell lymphoma family proteins and the inhibition of cytochrome C release and caspase-3 activation. These results indicate that MCE has neuroprotective effects in PD models and may be useful for preventing or treating PD.