Objective: Cerebral ischemic reperfusion injury (CIRI) is a common cerebrovascular disorder with high disability and morbidity that threatens human health. Former investigations found that dexmedetomidine (DEX) has a protective effect against CIRI, but regulatory mechanism is unclear.
Methods: The current study utilized C57BL/6 mice to establish a focal cerebral ischemic reperfusion model. Cerebral infarct volume was defined by 2, 3, 5-triphenyltetrazolium chloride (TTC) staining. BV2 cells and primary neurons were utilized for molecular mechanism studies after treatment with DEX or autophagy inhibitor 3-Methyladenine (3-Ma).
Results: Data revealed that DEX pretreatment protected nerves against CIRI. In vitro studies also found that DEX pretreatment enhanced microglial M2 polarization and protected against neuronal apoptosis by autophagy activation. Downregulation of hypoxia inducible factor (HIF)-1α or Beclin-1 inhibited the promotional effects of DEX on microglial M2 polarization and inhibited the protective effects of DEX against neuronal apoptosis.
Conclusion: The present study found that DEX treatment protects against CIRI by modulating microglial polarization via HIF-1α/Beclin1-mediated autophagy.
Keywords: Beclin1; Dexmedetomidine; HIF-1α; autophagy; cerebral ischemia reperfusion injury; microglial polarization.