BackgroundIn situ microglia and astrocytes begin to activate and participate in neuroinflammation after spinal cord injury (SCI), and the high expression of lipocalin 2 (Lcn2) and the activation of the Janus kinase-2 (JAK2)-signal transducer and activator of transcription-3 (STAT3) pathway promote the polarization of activated microglia and astrocytes towards the neurotoxic phenotype (M1 microglia and A1 astrocytes). We previously reported that photobiomodulation (PBM) can promote functional recovery by reducing neuroinflammation after SCI, but the mechanism of PBM on the microglia and astrocytes involved is still unclear. Therefore, the purpose of this study was to explore the role of the Lcn2 and JAK2-STAT3 pathways in the activation of M1 and A1 and the mechanism by which PBM may play a therapeutic role.MethodsPBM intervention was performed every day after the SCI model was established, and the activation of microglia and astrocytes was observed at different time points post injury (1, 3, 7, 14, 28 dpi). The level of tissue apoptosis, the number of surviving neurons, the recovery of motor function, the level of Lcn2 and the activation of JAK2-STAT3 were evaluated in the PBM group and the vehicle group. M1 and A1 cells were irradiated with PBM in vitro, and the JAK2-STAT3 pathway inhibitor cucurbitacin I, adenovirus transfection and recombinant Lcn2 protein were cotreated with PBM to explore the mechanism of the activation of M1 and A1 and the underlying effect of PBM.ResultsPBM inhibited the activation of neurotoxic microglia and astrocytes, decreased secondary inflammation and tissue apoptosis, increased the number of neurons retained, and promoted the recovery of motor function after SCI. The upregulation of Lcn2 and the activation of the JAK2-STAT3 pathway after SCI were suppressed by PBM. In vitro experiments also proved that PBM can inhibit the activation of M1 microglia and A1 astrocytes, and the effect is related to the level of Lcn2 and the activation of the JAK2-STAT3 pathway.ConclusionThe crosstalk of Lcn2/JAK2-STAT3 is involved in the activation of neurotoxic microglia and astrocytes after SCI, and this process can be alleviated by PBM.