Atractylodin alleviates neuroinflammation and protects neurological function after ischemic stroke in association with reduced NLRP3 inflammasome activation.

BACKGROUND: NOD-like receptor protein 3 (NLRP3) inflammasome-driven neuroinflammation contributes to ischemic stroke injury. Atractylodin (ART) shows anti-inflammatory activity, but its neuroprotective potential and mechanistic links to NLRP3 signaling after cerebral ischemia-reperfusion (I/R) injury remain to be defined.

MATERIALS AND METHODS: BV2 microglia were subjected to oxygen-glucose deprivation/reoxygenation (OGD/R), and rats underwent middle cerebral artery occlusion (MCAO) followed by reperfusion. ART was administered after reperfusion in vivo (10 or 30 mg/kg, once daily for 3 days) and during reoxygenation in vitro. Neurobehavioral outcomes and infarct volume were assessed in MCAO rats, along with measurements of neuronal apoptosis. NLRP3 inflammasome activation, gasdermin D (GSDMD)-dependent pyroptosis, pro-inflammatory cytokines, and microglial polarization markers were evaluated using immunoblotting, immunofluorescence, RT-qPCR, and enzyme-linked immunosorbent assay (ELISA).

RESULTS: In OGD/R-stimulated BV2 microglia, ART suppressed NLRP3 inflammasome activation and reduced GSDMD cleavage, accompanied by decreased IL-1β and IL-18 production. In the MCAO model, ART significantly improved neurological outcomes and reduced infarct volume and neuronal apoptosis. These protective effects were linked to a reduction in the expression of NLRP3 pathway components (NLRP3, ASC, and caspase-1) and GSDMD-N. Additionally, there was a shift in microglial responses toward an anti-inflammatory (M2-like) profile, which led to a decrease in pro-inflammatory markers.

CONCLUSION: ART confers neuroprotection in experimental ischemic stroke by inhibiting NLRP3 inflammasome-associated pyroptosis and modulating microglial inflammatory polarization, supporting its potential as a therapeutic candidate for ischemic stroke.