ß-elemene promotes microglial M2-like polarization against ischemic stroke via AKT/mTOR signaling axis-mediated autophagy.

ABSTRACT

BACKGROUND: Resident microglia- and peripheric macrophage-mediated neuroinflammation plays a predominant role in the occurrence and development of ischemic stroke. Microglia undergo polarization to M1/M2-like phenotype under stress stimulation, which mediates intracellular inflammatory response. ß-elemene is a natural sesquiterpene and possesses potent anti-inflammatory activity. This study aimed to investigate the anti-inflammatory efficacy and mechanism of ß-elemene in ischemic stroke from the perspective of balancing microglia M1/M2-like polarization. METHODS: The middle cerebral artery occlusion (MCAO) model and photothrombotic stroke model were established to explore the regulation effect of ß-elemene on the cerebral ischemic injury. The LPS and IFN-γ stimulated BV-2 cells were used to demonstrate the anti-inflammatory effects and potential mechanism of ß-elemene regulating M1/M2-like polarization in vitro. RESULTS: In C57BL/6 J mice subjected to MCAO model and photothrombotic stroke model, ß-elemene attenuated neurological deficit, reduced the infarction volume and neuroinflammation, thus improving ischemic stroke injury. ß-elemene promoted the phenotype transformation of microglia from M1-like to M2-like, which prevented neurons from oxygen and glucose deprivation/reoxygenation (OGD/R) injury by inhibiting inflammatory factor release, thereby reducing neuronal apoptosis. Mechanically, ß-elemene prevented the activation of TLR4/NF-κΒ and MAPK signaling pathway and increased AKT/mTOR mediated-autophagy, thereby promoting M2-like polarization of microglia. CONCLUSIONS: These results indicated that ß-elemene improved cerebral ischemic injury and promoted the transformation of microglia phenotype from M1-like to M2-like, at least in part, through AKT/mTOR-mediated autophagy. This study demonstrated that ß-elemene might serve as a promising drug for alleviating ischemic stroke injury.