Department of Orthopedics, Zhongda Hospital of Southeast University, Nanjing, China.
Department of Orthopedics, First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
Int Immunopharmacol. 2020 Nov;88:106988. doi: 10.1016/j.intimp.2020.106988. Epub 2020 Oct 13.
Neuroinflammation following spinal cord injury (SCI) leads to extensive secondary damage in neural tissue adjacent to the primary lesion foci. 5-Methoxytryptophan (5MTP) is a metabolite of tryptophan and proven to play a protective role in several inflammation-related diseases. However, the specific efficacy and molecular mechanism of 5MTP in SCI remains unknown. Here, we aimed to investigate the anti-inflammatory role of 5MTP in microglia-induced neuroinflammation and its therapeutic effect in SCI. To assess the effect of 5MTP in neuroinflammation, we used lipopolysaccharide (LPS) to stimulate microglia in vitro and detected the microglial phenotype using immunofluorescence staining, the inflammatory-related pathway using western blotting, and pro-inflammatory cytokines using ELISA and immunofluorescence. To explore the therapeutic effect of 5MTP in SCI, we performed contusion of the spinal cord in mice and measured the levels of neuroinflammation, glial accumulation, histological and functional recovery using ELISA, immunofluorescence staining, immunohistochemical staining, hematoxylin-eosin staining, Nissl staining and the Basso Mouse Scale, respectively. We found that treatment with 5MTP contributed to decreased activation of pro-inflammatory microglia and reduced the generation of inflammatory cytokines, including TNF-α, IL-1β, IL-6 and IL-18, by negative regulation of the p38-MAPK signaling pathway and NLRP3/caspase-1 expression. In vivo, administration of 5MTP showed mitigatory neuroinflammation levels associated with alleviated glial scar in SCI mice; hence, the neurological integrity and the neuronal survival, as well as locomotor function, were improved following 5MTP administration. 5MTP, as a novel anti-neuroinflammatory reagent, can attenuate activated microglia-induced secondary injury following SCI, and therefore, shows promise as a potential compound for application in a clinical trial for SCI therapy.
脊髓损伤 (SCI) 后的神经炎症导致原发性病变部位附近的神经组织发生广泛的继发性损伤。5-甲氧基色氨酸 (5MTP) 是色氨酸的代谢产物，已被证明在几种与炎症相关的疾病中发挥保护作用。然而，5MTP 在 SCI 中的具体疗效和分子机制尚不清楚。在这里，我们旨在研究 5MTP 在小胶质细胞诱导的神经炎症中的抗炎作用及其在 SCI 中的治疗效果。为了评估 5MTP 在神经炎症中的作用，我们使用脂多糖 (LPS) 在体外刺激小胶质细胞，使用免疫荧光染色检测小胶质细胞表型，使用 Western blot 检测炎症相关通路，使用 ELISA 和免疫荧光检测促炎细胞因子。为了探讨 5MTP 在 SCI 中的治疗效果，我们在小鼠的脊髓上进行挫伤，并使用 ELISA、免疫荧光染色、免疫组织化学染色、苏木精-伊红染色、尼氏染色和 Basso 小鼠量表分别测量神经炎症、神经胶质细胞聚集、组织学和功能恢复的水平。我们发现，5MTP 的治疗有助于通过负调控 p38-MAPK 信号通路和 NLRP3/caspase-1 表达，减少促炎小胶质细胞的激活和炎症细胞因子的产生，包括 TNF-α、IL-1β、IL-6 和 IL-18。在体内，5MTP 的给药表现出减轻的神经炎症水平与 SCI 小鼠中的神经胶质瘢痕减轻有关；因此，5MTP 给药后神经完整性和神经元存活以及运动功能得到改善。5MTP 作为一种新型抗炎试剂，可减轻 SCI 后激活的小胶质细胞引起的继发性损伤，因此有望成为治疗 SCI 的临床试验中应用的潜在化合物。
