Schwann Cell-Derived Extracellular Vesicles MFG-E8 Alleviates Neuropathic Pain After Peripheral Nerve Injury Through Inhibiting Ferroptosis in Dorsal Root Ganglion Neurons by Regulating the PPARγ/p53/SAT1/ALOX15 Pathway.

The dorsal root ganglion (DRG) plays a critical role in mediating neuropathic pain (NP) following peripheral nerve injury (PNI), although the underlying mechanism remains unclear. This study investigated how Schwann cell (SCs)-derived extracellular vesicles (SC-EVs) regulate neuronal ferroptosis in NP after PNI. After validating isolated SCs (S-100) and DRG neurons (NeuN), SC-EVs were characterized by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and western blotting for exosomal markers (Alix/CD9/CD63) and the absence of Calnexin. Co-localization of PKH67 with β-Tubulin-III confirmed SC-EVs uptake by DRG neurons. Biochemical assays and flow cytometry demonstrated SC-EVs suppressed ferroptosis in both LPS-stimulated DRG neurons and chronic constriction injury (CCI) rat models, while simultaneously inhibiting apoptosis, inflammation, and NP progression. Mechanistically, RT-qPCR and western blotting revealed aberrant expression of PPARγ, p53, SAT1, and ALOX15 in LPS/CCI models. Co-immunoprecipitation demonstrated that binding between PPARγ and p53 inhibits SAT1/ALOX15-mediated ferroptosis in DRG neurons. Notably, SC-EVs delivered MFG-E8 to upregulate PPARγ and suppress the activation of the p53/SAT1/ALOX15, thereby attenuating neuronal ferroptosis and ameliorating CCI-induced NP. In conclusion, MFG-E8 delivered via SC-EVs alleviates NP after PNI by modulating the PPARγ/p53/SAT1/ALOX15 signaling axis to inhibit CCI-induced ferroptosis, offering novel therapeutic insights.