Pro-resolving mediator maresin 1 ameliorates pain hypersensitivity in a rat spinal nerve ligation model of neuropathic pain

Abstract

Jie Gao,1,2,* Chaoliang Tang,3,4,* Lydia Wai Tai,5 Yeling Ouyang,2,6 Na Li,2,6 Zhiqiang Hu,2,6 Xiangdong Chen2,6 1Department of Anesthesiology, The First Affiliated Hospital of Anhui Medical University, Hefei, 230022, Anhui Provence, China; 2Department of Anesthesiology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, Hubei Province, China; 3Department of Anesthesiology, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei Province, China; 4Department of Anesthesiology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, Anhui Provence, China; 5Department of Anaesthesiology, The University of Hong Kong, Hong Kong SAR, China; 6Institute of Anesthesiology and Critical Care Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, Hubei Province, China *These authors contributed equally to this work Background: Pro-resolving mediators (PRMs) are considered as emerging analgesics for chronic pain. Maresin 1 (MaR1) is a newly identified member of PRMs, and recent studies implicate its potential role in some pain conditions. As the function of MaR1 in neuropathic pain remains unclear, we investigated the effects of MaR1 on pain hypersensitivity and the underlying mechanism using a rat spinal nerve ligation (SNL) model of neuropathic pain. Materials and methods: MaR1 (100 ng/10 μL) or commensurable artificial cerebrospinal fluid was delivered via intrathecal catheter from days 3 to 5 post-SNL followed by assessment of mechanical allodynia and thermal hyperalgesia. Ipsilateral L4–L5 spinal cord tissue was collected on day 7 post-SNL and assessed by Western blotting, enzyme-linked immunosorbent assay or immunohistochemistry. Results: Intrathecal MaR1 significantly attenuated mechanical allodynia and thermal hyperalgesia from day 5 to day 7 post-SNL, which was associated with decreased spinal levels of glial markers, GFAP and IBA1. It was also found that intrathecal MaR1 downregulated phosphorylation levels of NF-κB p65 and its nuclear translocation, as well as decreased protein levels of pro-inflammatory cytokines, TNF-α, IL-1β and IL-6. Further, MaR1 treatment restored PSD95 and synapsin II levels, suggesting that MarR1 also protected synaptic integrity. Conclusion: Our results indicate that MaR1 ameliorates the SNL-induced neuropathic pain by regulating glial activities and pro-inflammatory cytokines release. The present study offers insight into the potential of MaR1 as a novel intervention to ameliorate neuropathic pain. Keywords: maresin 1, neuropathic pain, spinal nerve ligation, inflammation, NF-κB p65

Keywords

• Maresin 1
• Neuropathic pain
• Spinal nerve ligation
• Inflammation
• NF-κB p65