Tanshinone IIA Attenuates the Inflammatory Response and Apoptosis after Traumatic Injury of the Spinal Cord in Adult Rats Xin Yin1., Yue Yin2., Fa-Le Cao3., Yu-Fei Chen 1 , Ye Peng 1 , Wu-Gang Hou 4 , Shu-Kai Sun 5 , Zhuo- 1 Jing Luo * 1 Institute of Orhopaedics Surgery, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi, P.R. China, 2 Department of Plastic Surgery, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi, P.R. China, 3 Department of Neurology and Respiration, The 222th Hospital of CPLA, Jilin, Jilin, P.R. China, 4 Department of Anesthesia, Xijing Hospital, Xi’an, Shaanxi, P.R. China, 5 Department of Operative Dentistry and Endodontics, School of Stomatology, Fourth Military Medical University, Xi’an, Shaanxi, P.R. China Abstract Background: Spinal cord injury (SCI), including immediate mechanical injury and secondary injury, is associated with the inflammatory response, apoptosis and oxidative stress in response to traumatic injury. Tanshinone IIA (TIIA) is one of the major extracts obtained from Salvia miltiorrhiza BUNGE, which has anti-inflammatory and anti-apoptotic effects on many diseases. However, little is known about the effects of TIIA treatment on SCI. Therefore, the aim of the present study is to evaluate the pharmacological action of TIIA on secondary damage and the underlying mechanisms of experimental SCI in rats. Methodology/Principal Findings: SCI was generated using a weight drop device on the dorsal spinal cord via a two-level T9-T11 laminectomy. SCI in rats resulted in severe trauma, characterized by locomotor disturbance, edema, neutrophil infiltration, the production of astrocytes and inflammatory mediators, apoptosis and oxidative stress. TIIA treatment (20 mg/ kg, i.p.) after SCI induced significant effects: (1) improved motor function (Basso, Beattie and Bresnahan scores), (2) reduced the degree of tissue injury (histological score), neutrophil infiltration (myeloperoxidase activity) and the expression of astrocytes, (3) inhibited the activation of SCI-related pathways, such as NF-kB and MAPK signaling pathways, (4) decreased the production of pro-inflammatory cytokines (TNF-a, IL-1b, and IL-6) and iNOS, (5) reduced apoptosis (TUNEL staining, and Bcl-2 and caspase-3 expression) and (6) reversed the redox state imbalance. Conclusions/Significance: The results clearly show that TIIA has a prominent protective effect against SCI through inhibiting the inflammatory response and apoptosis in the spinal cord tissue after SCI. Citation: Yin X, Yin Y, Cao F-L, Chen Y-F, Peng Y, et al. (2012) Tanshinone IIA Attenuates the Inflammatory Response and Apoptosis after Traumatic Injury of the Spinal Cord in Adult Rats. PLoS ONE 7(6): e38381. doi:10.1371/journal.pone.0038381 Editor: Partha Mukhopadhyay, National Institutes of Health, United States of America Received January 10, 2012; Accepted May 4, 2012; Published June 1, 2012 Copyright: 2012 Yin 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 study was supported by a grant from the Istitute of Orthopaedics, Fourth Military Medical University. 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: zjluo@fmmu.edu.cn . These authors contributed equally to this work. Introduction Spinal cord injury (SCI) is a prevalent traumatic injury in the central nervous system (CNS) that leads to motor and sensory dysfunction in all ages. Trauma to the spinal cord causes immediate mechanical damage and a cascade of secondary damage [1]. After traumatic insult to the spinal cord, the tissues exhibit a progressive morphologic change, such as ischemia, hemorrhage, and edema [1,2]. The secondary damage to the spinal cord develops within from minutes to hours following initial mechanical damage, and leads to a cascade of extracellular and intercellular events, including the infiltration of inflammatory cells, the destruction of neuronal and glial cells, neuronal dysfunction and death, and oxidative stress. Although great efforts have made to improve the outcome of patients with SCI, advances in therapy for this disease have been limited. The pathophysiological mechanisms of SCI are complicated. During this period, inflammatory reactions are a crucial process of the secondary injury [3,4]. Proinflammatory cytokines, such as TNF-a, IL-1b and IL-6, are primarily produced by inflammatory cells, and exist widely at the site of the lesion [1,5]. Studies have demonstrated that the activation of MAPK signaling pathways following SCI is an important step in the inflammatory response [6]. Moreover, NF-kB is a major transcription factor that modulates the production of pro-inflammatory cytokines in the CNS [7,8]. Previous studies have shown that apoptosis, which is regulated primarily through the caspase and Bcl-2 families [9,10], is an important event in the secondary injury after SCI [11]. Reports indicate that apoptosis is involved in secondary degener- PLoS ONE | www.plosone.org 1 June 2012 | Volume 7 | Issue 6 | e38381