Objective:To investigate the neuro-protective effects of Acanthopanax senticosus Harms (EAS)on mesencephalic mitochondria and the mechanism of action,using a mouse model of Parkinson\'s disease (PD).Methods:The chemical fingerprint analysis of the extract of Acanthopanax senticosus Harms (FAS) was performed using the ultra performance liquid chromatograph and time of flight mass spectrometry.Thirty mice were randomly divided into the control group,the MPTP model group,and the EAS treated group with MPTP (MPTP+EAS group,10 in each group).The MPTP model group and the MPTP+EAS group received MPTP-HCI (30 mg/kg i.p) once a day for 5 days.The control group received an equal volume of saline (20 mL/kg i.p) once a day for 5 days.Induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride daily (MPTP-HCI,30 mg/kg) for 5 days,the PD mice were treated with EAS at 45.5 mg/kg daily for 20 days.The behavioral testing of mice was carried out using the pole-climbing test.The integrity and functions of neurons were examined in mesencephalic mitochondrida in a PD mouse model,including nicotinamide adenine dinucleotide dehydrogenase ubiquinone flavoprotein 2 (NDUFV2),mitochondrially encoded nicotinamide adenine dinucleotide dehydrogenase 1 (MT-ND1),succinate dehydrogenase complex subunit A (SDHA),and succinate dehydrogenase cytochrome b560 subunit (SDHC).Results:After treatment with EAS,the behavioral changes induced by MPTP were attenuated significantly (P＜0.05).EAS protected the mesencephalic mitochondria from swelling and attenuated the decreases in their membrane potential (both P＜0.05),which was supported by an ultra-structural level analysis.The changes in reactive oxygen species (ROS),malonic dialdehyde (MDA),oxidative phosphorylation (OXPHOS) system 4 subunits levels and PD-related proteins expressions (parkin,Pink1,DJ-1,α-synuclein,and Lrrk2) reverted to near normal levels (all P＜0.05),based on the results of immune-histological and Westem blotting observations.Conclusions:The neuro-protective effects of EAS are linked to protecting mice against MPTP-induced mitochondrial dysfunction and structural damage.Therefore,EAS is a promising candidate for the prevention or treatment of mitochondrial neurodegenerative disorders,such as PD.