Stress‐induced phosphoprotein 1 restrains spinal cord ischaemia‐reperfusion injury by modulating NF‐κB signalling

Spinal cord injury (SCI), a major cause of disability, causes high global disease and economic burdens. Stress‐induced phosphoprotein 1 (STIP1) has been identified to be involved in spinal cord ischaemia‐reperfusion injury (SCII); however, the effect of STIP1 on SCII remains unclear until now. This study aimed to examine the role of STIP1 in SCII and unravel the possible mechanisms. Western blotting and immunohistochemical staining showed that STIP1 expression rapidly increased and then decreased in rat spinal cord following SCII treatment. Neurological function scoring, HE staining, immunohistochemical staining and Western blotting revealed that STIP1 overexpression alleviated SCII‐induced motor dysfunction of hind limbs, neuronal loss and inflammation in spinal cord, and inhibited activity of nuclear factor kappa B (NF‐κB) signalling in rats. Immunoprecipitation identified that STIP1 was co‐located with Iba‐1. In addition, STIP1 was found to ameliorate oxygen and glucose deprivation (OGD)‐induced inflammation and activation of NF‐κB signalling in mouse microglia BV2 cells, and STIP1 resulted in decrease of heat shock protein family A member 8 (HSPA8), increase of IκBβ expression and reduced binding of IκBβ to HSPA8 in BV2 cells. The results of the present study demonstrate that STIP1 alleviates ischaemia/reperfusion‐induced neuronal injury and inflammation in rat spinal cord and mouse microglial cells by deactivating NF‐κB signalling. These findings may provide novel insights for the clinical diagnosis and treatment of SCI.