Cytokine expressions of spinal cord injury treated by neurotropin and nafamostat mesylate

Background: Spinal cord injury (SCI) leads to severe physical disability and sensory dysfunction. Neurotropin (NTP) has been used clinically to alleviate neuropathic pain, while nafamostat mesylate (NM) used clinical on pancreatitis patients through inhibiting synthetic serine protease. Our previous studies showed that NTP and NM were able to repair SCI. However, the underlying mechanism has not been fully explored after treatment with these 2 different drugs. Methods: The drugs NTP and NM were administered on a contusion SCI Wistar rat model. Cytokine array analysis was performed to describe the changes of 67 proteins after acute SCI. Hierarchical clustering and volcano plot analysis were conducted to clarify protein change profiles. The differently expressed proteins related to biological processes were analyzed by functional protein association networks, Gene Ontology and pathway analysis. Flow cytometric analysis was detected to reflect the activation of immune system after drug intervention, while withdrawal threshold and BBB score were detected to evaluated the mechanical allodynia and functional recovery after SCI. Results: HGF, 13-NGF, and activin were the 3 most upregulated proteins, while the receptor for RAGE, IL-1?, and TNF-? were the 3 most downregulated proteins after NTP treatment. Adiponectin, decorin and CTACK were the 3 most upregulated proteins, while RAGE, IL-1?, and IL-113 were the 3 most downregulated proteins in the NM group. Number of lymphocytes was decreased while BBB score was increased both in NTP and NM group. But only NTP could improve mechanical pain threshold after SCI. Conclusions: The PI3K-Akt, Jak-STAT signaling pathway and apoptosis might participate in SCI restoration by NTP, while the MAPK and NOD-like receptor signaling pathway may participated in repairing SCI with NM. We concluded that NTP regulated the microenvironment via a neuroprotective effect and inhibition of inflammation to repair SCI, while NM healed SCI through an anti-inflammatory effect. Both NTP and NM could down-regulate the activation of immune system and improve the functional recovery while only NTP could improve the pathological neuralgia after SCI. Elucidating the molecular mechanisms of these 2 clinical drugs indicates that they their expected to be effective clinical treatment for SCI.

Automated summary

This study demonstrated that NTP repairs SCI by regulating the microenvironment through a neuroprotective effect and inhibition of inflammation, while NM heals SCI through an anti-inflammatory effect. Both drugs down-regulate immune system activation and improve functional recovery, but only NTP improves pathological neuralgia after SCI. Elucidating the molecular mechanisms of these drugs suggests their potential as effective clinical treatments for SCI.