In recent decade microglia have been found to have a central role in the development of chronic neuropathic pain after injury to the peripheral nervous system. It is widely accepted that peripheral nerve injury triggers microglial activation in the spinal cord, which contributes to heightened pain sensation and eventually chronic pain states. The contribution of microglia to chronic pain arising after injury to the central nervous system, such as spinal cord injury (SCI), has been less studied, but there is evidence supporting microglial contribution to central neuropathic pain. In this systematic review, we focused on post-SCI microglial activation and how it is linked to emergence and maintenance of chronic neuropathic pain arising after SCI. We found that the number of studies using animal SCI models addressing microglial activity is still small, compared with the ones using peripheral nerve injury models. We have collected 20 studies for full inclusion in this review. Many mechanisms and cellular interactions are yet to be fully understood, although several studies report an increase of density and activity of microglia in the spinal cord, both in the vicinity of the injury and in the spared spinal tissue, as well as in the brain. Changes in microglial activity come with several molecular changes, including expression of receptors and activation of signalling pathways. As with peripheral neuropathic pain, microglia seem to be important players and might become a therapeutic target in the future.

中文翻译：

---

小胶质细胞参与脊髓损伤相关慢性神经病理性疼痛——系统评价

近十年来，人们发现小胶质细胞在周围神经系统损伤后慢性神经病理性疼痛的发展中发挥着核心作用。人们普遍认为，周围神经损伤会触发脊髓中的小胶质细胞激活，从而导致疼痛感增强，最终导致慢性疼痛状态。小胶质细胞对中枢神经系统损伤（例如脊髓损伤（SCI））后引起的慢性疼痛的影响研究较少，但有证据支持小胶质细胞对中枢神经病理性疼痛的影响。在这篇系统综述中，我们重点关注 SCI 后小胶质细胞的激活及其与 SCI 后慢性神经病理性疼痛的出现和维持的关系。我们发现，与使用周围神经损伤模型的研究相比，使用动物 SCI 模型研究小胶质细胞活性的研究数量仍然很少。我们收集了 20 项研究，将其全部纳入本次综述中。许多机制和细胞相互作用尚未完全了解，尽管一些研究报告脊髓中小胶质细胞的密度和活性增加，无论是在损伤附近、幸存的脊髓组织以及大脑中。小胶质细胞活性的变化伴随着多种分子变化，包括受体的表达和信号通路的激活。与周围神经性疼痛一样，小胶质细胞似乎是重要的参与者，并且可能成为未来的治疗靶点。