BackgroundAn ischemic insult at the optic nerve is followed by detrimental neuroinflammation that results in the loss of the retinal ganglion cells (RGCs) and vision. NF-κB is the key transcription factor of inflammatory cytokines in response to neuroinflammatory events. Icariin, an anti-inflammatory drug, is involved in the regulation of NF-κB activation. However, the protective mechanisms of icariin-induced NF-κB activation remain little known. Here, the protective mechanisms of icariin-induced NF-κB activation were investigated in experimental optic nerve ischemia. MethodsThe GOLD bio-informatics tool was used to select target drug based on CEBP-β binding affinity. The neuroprotective effects of target drug, Icariin, were assessed by measuring the flash visual electrode potentials, density of fluorogold-labeled cells, and TUNEL-positive cells in ganglion cell layer. The processes affecting RGC death were probed using optical coherence tomography, immunohistochemistry and immunoblotting techniques. ResultsThe simulation analysis and in vivo test demonstrated that the binding complex of icariin and CEBP-β significantly induced endogenous G-CSF expression. A single intravitreal injection of poly(lactic-co-glycolic acid) (PLGA)-icariin preserved visual function and RGC density after optic nerve infarct. The optic nerve edema, RGC apoptosis, and macrophage infiltration were inhibited by treatment with PLGA-icariin. The endogenous G-CSF expression switched the canonical NF-kB activation to the noncanonical NF-kB activation by promoting an alternative phosphorylation reaction of IKK-β. The noncanonical NF-κB activation further promoted the M2 microglia/macrophage polarization and AKT1 activation, which prevented the neuroinflammation and RGC apoptosis Granulocyte colony-stimulating factor. ConclusionOur study concluded that the protective mechanism of icariin is a G-CSF-induced non-canonical NF-kB activation, which may provide a potential therapeutic strategy for a patient with neuroinflammation diseases.