Maresin 1调节巨噬细胞亚型减轻神经病理性疼痛的机制研究

The mechanisms of neuropathic pain remain unclear and effective treatments are lack. Our previous studies demonstrated that neuropathic pain was closely linked to the active peripheral nerve regeneration. Moreover, macrophage plays key roles in initiating the peripheral nerve regeneration process, contributing to Wallerian degeneration, and is involved in various types of pain. Recent studies suggested specialized proresolving mediators (SPM) have the characteristics of anti-inflammatory, analgesic and proresolving, and regulate various types of pain. Maresin 1 is a newly discovered efficient SPM, its effect on neuropathic pain is still elusive. Previous researches showed that maresin 1 could stimulate phagocytosis of macrophages and accelerate tissue regeneration. Therefore, we hypothesized that maresin 1 could alleviated neuropathic pain via regulating macrophage subtypes and nerve regeneration. To test the hypothesis, we will reproduce the neuropathic pain on the whole and cell levels, and examine the effects of maresin 1 on neuropathic pain with emphasis on macrophage subtypes changes and nerve regeneration by using molecular biology, fluorescent-assisted cell sorting and electrophysiological techniques. Our study will clarify the occurance and development mechanisms of neuropathic pain from a new perspective, and provide a new target for the treatment of neuropathic pain.

神经病理性疼痛发病机制不清，其治疗仍是医学界的难题。课题组前期研究证实神经病理性疼痛与外周神经再生相关，且巨噬细胞可启动外周神经再生，导致沃勒变性，参与疼痛的发生和发展。有文献报道，特异性促缓解介质（SPM）具有抗炎、镇痛、促缓解等特性，可调控多种类型的疼痛。Maresin 1是新近发现的一种高效能SPM，其对神经病理性疼痛的作用尚不清楚。研究提示，maresin 1可刺激巨噬细胞吞噬，加速组织再生。因此，我们推测maresin 1可能通过改变巨噬细胞功能，影响受损神经的再生/修复过程，减轻神经病理性疼痛。为验证此假说，我们在整体和细胞两个水平复制病理性疼痛模型，采用分子生物学、荧光激发细胞分类术、电生理技术，观察maresin 1调控神经病理性疼痛的作用，重点关注其对巨噬细胞亚型改变及神经再生的影响。本课题将从新的视角阐明神经病理性疼痛的发生和发展机制，为神经病理性疼痛的治疗提供新靶点。

神经病理性疼痛发病机制不清，其治疗仍是医学界的难题。既有研究显示神经病理性疼痛与巨噬细胞有关，不同类型巨噬细胞对慢性疼痛的发展可能具有不同的调节角色。在本研究项目中，应用crush神经病理性疼痛小鼠模型，申请人发现Iba1在小鼠背根神经节（DRG）和受损神经处表达明显升高，且CCL2/CCR2信号通路在神经损伤病理性疼痛后表达上调。进一步的研究发现给予clodronate清除巨噬细胞或给予CCR2拮抗剂INCB3344均可减轻实验动物的神经病理性疼痛行为，并降低DRG中Iba1和CCL2/CCR2信号通路表达。高效能的特异性促缓解介质Maresin 1（MaR1）具有抗炎、镇痛、促缓解等特性。申请人进一步给予MaR1治疗，发现MaR1可缓解小鼠神经损伤引起的神经病理性疼痛。MaR1调控促炎性巨噬细胞CCR2的表达，参与神经病理性疼痛。进一步的研究发现，高脂饮食（HFD）加重坐骨神经损伤模型（crush模型）实验小鼠的疼痛，且HFD进一步增加crush小鼠DRG中Iba1阳性和CCR2 阳性巨噬细胞的数量。CCR2拮抗剂INCB3344抑制HFD+crush手术引起的DRG巨噬细胞浸润。而MaR1可缓解HFD小鼠crush手术引起的神经病理性疼痛。本项目研究显示MaR1通过调控DRG痛觉神经元CCL2/CCR2信号通路参与神经损伤引起的神经病理性疼痛，MaR1可能为治疗神经病理性疼痛提供了新的策略。