Pearl Powder Fluorescent Carbon Dots Alleviate Neuroinflammation in Cerebral Ischemia/Reperfusion Through Suppression of Anxa2/NF-κB Signaling Pathway

Purpose: This study aimed to enzymatically synthesize pearl powder fluorescent carbon dots (PFCDs) and investigate their neuroprotective potential against cerebral ischemia/reperfusion injury (CIRI) by modulating the Anxa2/NF-κB signaling pathway. Methods: PFCDs were synthesized through enzymatic digestion and characterized. Neuroprotective effects were assessed using an in vitro oxygen-glucose deprivation/reoxygenation (OGD/R) model in PC12 cells and a middle cerebral artery occlusion/reperfusion (MCAO/R) rat model. Cell viability, neurological function, cerebral infarct volume, and neuronal injury were evaluated. Expression of Anxa2/NF-κB signaling pathway proteins and inflammatory cytokines (TNF-α, IL-6, IL-1β) was analyzed by Western blot, immunofluorescence, and ELISA. Results: The synthesized PFCDs exhibited an organic-inorganic hybrid structure, uniform particle size below 10 nm, and distinctive optical properties. In vitro, PFCDs enhanced cell viability under OGD/R conditions, inhibited phosphorylation of Anxa2 and NF-κB p65, and reduced secretion of pro-inflammatory cytokines (TNF-α, IL-6, IL-1β). In vivo, treatment with PFCDs in MCAO/R rats improved neurological function, reduced cerebral infarct volume, and alleviated neuronal injury. These protective effects were linked to downregulation of the Anxa2/NF-κB signaling pathway and reduced serum levels of inflammatory cytokines. Conclusion: We successfully achieved the enzymatic synthesis of carbon dots from pearl powder, characterized by a unique organic-inorganic hybrid structure. PFCDs effectively alleviated CIRI-induced neuroinflammation by suppressing the Anxa2/NF-κB signaling pathway, highlighting their therapeutic potential as a nanomedicine derived from natural products.