Edaravone Guards Dopamine Neurons in a Rotenone Model for Parkinson’s Disease Nian Xiong1,2., Jing Xiong1., Ghanshyam Khare1., Chunnuan Chen1, Jinsha Huang 1 , Ying Zhao2, Zhentao Zhang 1 , Xian Qiao1, Yuan Feng 1 , Harrish Reesaul1, Yongxue Zhang3, Shenggang Sun 1 , Zhicheng Lin2*, Tao Wang 1 * 1 Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Hubei, China, 2 Department of Psychiatry and Harvard NeuroDiscovery Center, Harvard Medical School, Division of Alcohol and Drug Abuse, and Mailman Research Center, McLean Hospital, Belmont, Massachusetts, United States of America, 3 Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Hubei Province Key Laboratory of Molecular Imaging, Wuhan, Hubei, China Abstract 3-methyl-1-phenyl-2-pyrazolin-5-one (edaravone), an effective free radical scavenger, provides neuroprotection in stroke models and patients. In this study, we investigated its neuroprotective effects in a chronic rotenone rat model for Parkinson’s disease. Here we showed that a five-week treatment with edaravone abolished rotenone’s activity to induce catalepsy, damage mitochondria and degenerate dopamine neurons in the midbrain of rotenone-treated rats. This abolishment was attributable at least partly to edaravone’s inhibition of rotenone-induced reactive oxygen species production or apoptotic promoter Bax expression and its up-regulation of the vesicular monoamine transporter 2 (VMAT2) expression. Collectively, edaravone may provide novel clinical therapeutics for PD. Citation: Xiong N, Xiong J, Khare G, Chen C, Huang J, et al. (2011) Edaravone Guards Dopamine Neurons in a Rotenone Model for Parkinson’s Disease. PLoS ONE 6(6): e20677. doi:10.1371/journal.pone.0020677 Editor: Tianzi Jiang, Institute of Automation, Chinese Academy of Sciences, China Received December 8, 2010; Accepted May 8, 2011; Published June 3, 2011 Copyright: 2011 Xiong et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This work was supported by grants from the National Natural Science Foundation of China (30870866), the Wuhan Science and Technology Bureau, China (20066002100) and the Hubei Provincial Science & Technology Department, China (2006ABA130) and U. S. National Institutes of Health grant R01DA021409 (to Z.L.). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. * E-mail: wangtaowh@yahoo.cn (TW); zhicheng_lin@hms.harvard.edu (ZL) . These authors contributed equally to this work. Introduction Parkinson’s Disease (PD), characterized by tremor, rigidity, bradykinesia, and postural instability, is the second most common neurodegenerative disease which affects 1.7% of population aging sixty-five or elder [1,2]. Although the pathogenesis of PD is not completely understood, environmental and genetic factors are believed to play important roles [2,3,4]. Subcellularly, reactive oxygen species (ROS) over-generation, oxidative stress and mitochondria dysfunction are well recognized in the pathogenesis of PD [3,5]. Edaravone is a powerful free radical scavenger that has been clinically used to reduce the neuronal damage following cerebral ischemic stroke in Japan and China [6]. Neuroprotective effects of edaravone are shown in neonatal hypoxic-ischemic encephalop- athy [7], acute intracerebral hemorrhage [6,8], subarachnoid hemorrhage [9], amyotrophic lateral sclerosis [10], traumatic brain injury [11,12] either animal models or patients. In all of these diseases, free radicals contribute to neuronal death. In PD, protein aggregation further generates cellular stresses that can initiate or feed into pathways to cell death evoked by oxidative stress [13]. These results illumine that edaravone may protect dopaminergic (DA) neurons and slow down the neurodegeneration in PD through anti-oxidative mechanisms. Previous studies showed the protective effects of edaravone in 6- hydroxydopamine (6-OHDA)-treated rodent [14] and 1-methyl-4- phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced murine par- kinsonian animal models [15]. However, it was reported that edaravone only reduced MPTP neurotoxicity in substantia nigra (SNc) but not in striatum (CPu) in a parkinsonian mouse model [15]. On the other hand, edaravone exerted neuroprotective effects on the whole nigrostriatal DA systems (SNc and CPu) in a 6-OHDA-induced rat model [14]. Although edaravone is involved in the anti-apoptotic, anti-oxidative and anti-inflammatory pathways in the 6-OHDA-induced parkinsonian rodent model [14], the detailed mechanisms underlying the neuroprotective effects of edaravone have not been completely understood. In this study, our aims were to further examine the effect of edaravone in chronic rotenone-induced parkinsonian rodent animals, and utilize the findings to further characterize the neuroprotective mechanisms of edaravone by accessing PD- associated risk factors including Bcl-2 family regulation, ROS generation, SNc ultrastructure, peripheral pathological changes, and VMAT2 expression level. Materials and Methods Drugs and chemicals Rotenone, chloral hydrate, 3,39-diaminobenzidine, Glutaralde- hyde, hematoxylin and eosin were purchased from Sigma (St. Louis, MO, USA). Triton-X100, paraformaldehyde and dimethyl sulfoxide (DMSO) were from Amresco (Solon, OH, USA). PLoS ONE | www.plosone.org 1 June 2011 | Volume 6 | Issue 6 | e20677