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Updated: Nov 30, 2025
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Published on: June 24, 2025
Treatment with 5-methoxytryptophan attenuates microglia-induced neuroinflammation in spinal cord trauma
Xin Hong1, Fan Jiang2, You Li2
1Department of Orthopedics, Zhongda Hospital of Southeast University, Nanjing, China.
Abstract:
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.
Insights
5-Methoxytryptophan (5MTP) reduces neuroinflammation and secondary damage after spinal cord injury (SCI). This tryptophan metabolite alleviates microglial activation and improves functional recovery, showing promise for SCI therapy.
Area of Science:
- Neuroscience
- Immunology
- Pharmacology
Background:
- Neuroinflammation exacerbates secondary damage following spinal cord injury (SCI).
- 5-Methoxytryptophan (5MTP), a tryptophan metabolite, exhibits protective effects in inflammatory diseases.
- The role and mechanism of 5MTP in SCI are not well understood.
Purpose of the Study:
- To investigate the anti-inflammatory effects of 5MTP on microglia-induced neuroinflammation.
- To determine the therapeutic potential of 5MTP in a mouse model of SCI.
Main Methods:
- In vitro: LPS-stimulated microglia assessed for phenotype, inflammatory pathways (Western blotting), and cytokines (ELISA, immunofluorescence).
- In vivo: Mouse SCI model evaluated for neuroinflammation, glial scarring, histology, and functional recovery (Basso Mouse Scale).
Main Results:
- 5MTP treatment decreased pro-inflammatory microglia activation and reduced key cytokines (TNF-α, IL-1β, IL-6, IL-18).
- 5MTP inhibited the p38-MAPK signaling pathway and NLRP3/caspase-1 expression.
- In vivo, 5MTP mitigated neuroinflammation, reduced glial scarring, improved neuronal survival, and enhanced locomotor function in SCI mice.
Conclusions:
- 5MTP demonstrates significant anti-neuroinflammatory properties by modulating microglial activation and inflammatory signaling.
- 5MTP treatment promotes histological and functional recovery after SCI.
- 5MTP is a promising therapeutic candidate for clinical application in SCI treatment.
