Lycium barbarum polysaccharide promotes motor function recovery in rats after spinal cord injury by regulating macrophage /microglial polarization

Macrophage and microglial polarization are key drivers of localised inflammatory responses following spinal cord injury (SCI). The equilibrium between the anti-inflammatory and pro-inflammatory effects mediated by polarised cells plays a critical role in influencing neurological recovery post-SCI. Lycium barbarum polysaccharide (LBP), a bioactive compound derived from Lycium barbarum, has shown potential in modulating inflammatory responses and enhancing neurofunctional recovery, yet its underlying mechanisms are still not fully understood. We selected 48 adult female rats as the experimental subjects for the in vivo study. Random assignment placed the rats into three distinct groups ( n ​= ​16): Sham, SCI, and SCI ​+ ​LBP. A rat spinal cord contusion model was utilised to evaluate the therapeutic effects of LBP on histological repair and locomotor recovery following SCI. Inflammatory cytokine levels at the injury site were quantified. In vitro , a lipopolysaccharide (LPS)-induced bone marrow-derived macrophage (BMDM) model was employed to assess the anti-inflammatory effects of LBP, with subsequent analysis of inflammatory mediator profiles and macrophage M1/M2 polarization status. LBP treatment significantly improved hindlimb motor function and enhanced nerve conduction capacity in SCI rats, accompanied by reduced histological damage. Moreover, LBP substantially downregulated pro-inflammatory cytokine expression at the injury site. Mechanistically, LBP suppressed M1 polarization while promoting M2 polarization of macrophages and microglia. LBP offers neuroprotective effects by mitigating post-SCI inflammatory responses via modulation of macrophage and microglial polarization to an anti-inflammatory phenotype. These results provide preclinical evidence for the potential application of LBP as a treatment for SCI.