Lupeol mitigates spinal cord injury by modulating microglial M1/M2 polarization via Na+/K+-ATPase-mediated mitophagy

Abstract

Spinal cord injury (SCI) often results in severe disability or even death, with inflammation playing a critical role in hindering recovery. Although Lupeol is known for its potent anti-inflammatory properties, its specific role in SCI-induced inflammation remains underexplored. In this study, an in vitro inflammation model was established using LPS-stimulated BV2 microglia. Lupeol treatment effectively counteracted LPS-induced reductions in Na⁺/K⁺-ATPase (NKA) activity, suppression of mitophagy, M1 polarization of microglia, release of inflammatory factors, and increased pyroptosis. Mechanistically, Lupeol alleviated microglial inflammation by enhancing mitophagy through the activation of NKA activity. Furthermore, Lupeol upregulated NKA activity and mitophagy by activating the AMPKα2-mTOR-TFEB pathway. In vivo, a mouse model of SCI was established, and Lupeol was administered daily via intraperitoneal injection. Lupeol treatment significantly reduced neuronal loss, promoted microglial polarization from the M1 to the M2 phenotype, attenuated inflammation, and improved motor function recovery in SCI mice. In conclusion, Lupeol promotes mitophagy by enhancing NKA activity via the AMPK–mTOR–TFEB pathway, thereby suppressing the pro-inflammatory phenotype of microglia and mitigating SCI progression.