BackgroundNeuropathic pain (NP) is a prevalent disease, which badly impairs the life quality of patients. The underlying mechanism of NP is still not fully understood. It has been reported that spinal Annexin A10 (ANXA10) contributes to NP. This study aims at exploring the underlying mechanisms of spinal ANXA10 in regulating NP in rats.MethodsSpinal nerve ligation (SNL) was adopted to establish a NP model in rats. After SNL, paw withdrawal threshold and paw withdrawal latency were recorded to measure pain behaviors, RT-PCR was used to check the change of the expression of spinal ANXA10 mRNA, western blot analysis was used to detect the change of the protein level of ANXA10, nuclear factor kappa B (NF-κB), and maisrix metalloproteinase-9 (MMP-9) in the spinal cord. The levels of proinflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukine-1β (IL-1β), and interleukine-6 (IL-6), were explored by ELISA kits. The effects of both knockdown of spinal ANXA10 and inhibition of NF-κB on pain behaviors and the expression of MMP-9 and proinflammatory cytokines were investigated.ResultsOur present findings highlighted that SNL caused pain hypersensitivity and increased the expression of spinal ANXA10/pNF-κB, TNF-α, IL-1β, and IL-6 both in the early and late phase of NP in rats, while spinal MMP-9 was only slightly increased in the early phase of NP. Knockdown of ANXA10 at the spinal cord level suppressed the SNL-induced hyperalgesia and blocked the activation of NF-κB, TNF-α and IL-1β both in the early and late phase of NP. Spinal ANXA10 knockdown could prevent the upregulation of spinal MMP-9 in the early phase and inhibit IL-6 expression in the late phase of SNL-induced NP.ConclusionsIn conclusion, spinal ANXA10/NF-κB/MMP-9 pathway, along with the activation of proinflammatory cytokines, was involved in the SNL-induced NP. MMP-9 may act as the downstream target of ANXA10/NF-κB pathway in the development rather than the maintenance of NP.

中文翻译：

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脊髓膜联蛋白A10/NF-κB/MMP-9通路参与大鼠神经病理性疼痛的发生

背景神经病理性疼痛（NP）是一种普遍存在的疾病，严重影响患者的生活质量。NP的潜在机制仍未完全了解。据报道，脊髓膜联蛋白 A10 (ANXA10) 有助于 NP。本研究旨在探讨脊髓ANXA10调节大鼠NP的潜在机制。方法采用脊髓神经结扎术（SNL）建立大鼠NP模型。SNL后，记录缩爪阈值和缩爪潜伏期测量疼痛行为，RT-PCR检测脊髓ANXA10 mRNA表达的变化，Western blot分析ANXA10蛋白水平的变化，核因子κB（NF-κB）和脊髓中的maisrix金属蛋白酶-9（MMP-9）。促炎细胞因子的水平，包括肿瘤坏死因子-α（TNF-α），白细胞介素 1β (IL-1β) 和白介素 6 (IL-6)，通过 ELISA 试剂盒进行了探索。研究了脊髓ANXA10的敲低和NF-κB的抑制对疼痛行为的影响以及MMP-9和促炎细胞因子的表达。结果我们目前的研究结果强调SNL引起疼痛超敏反应并增加脊髓ANXA10/pNF-κB的表达、TNF-α、IL-1β 和 IL-6 在大鼠 NP 的早期和晚期均出现，而脊髓 MMP-9 在 NP 早期仅略有增加。在脊髓水平敲除 ANXA10 抑制了 SNL 诱导的痛觉过敏，并在 NP 的早期和晚期阻断了 NF-κB、TNF-α 和 IL-1β 的激活。脊髓ANXA10敲低可以阻止脊髓MMP-9在SNL诱导的NP早期阶段的上调并抑制IL-6的表达。结论综上所述，脊髓ANXA10/NF-κB/MMP-9通路以及促炎细胞因子的激活参与了SNL诱导的NP。MMP-9 可能作为 ANXA10/NF-κB 通路的下游靶点在 NP 的发展而不是维持。