4-Hydroxybenzyl alcohol confers neuroprotection through up-regulation of antioxidant protein expression

An herb-derived phenolic compound, 4-hydroxybenzyl alcohol (4-HBA), exhibits beneficial effects in cerebral ischemic injury. However, the molecular mechanisms underlying this observation remain unclear. Here we used an in vitro ischemic model of oxygen-glucose deprivation followed by reperfusion (OGD/R) and an in vivo ischemic model of middle cerebral artery occlusion to investigate the relevant neuroprotective mechanisms. We demonstrated that 4-HBA reduced the neuronal injury, LDH release, and up-regulation of 8-hydroxydeoxyguanosine (8-OHdG) induced by OGD/R. Furthermore, 4-HBA reduced the cerebral infarct size and improved the behavioral parameters after cerebral ischemia. These neuroprotective effects may be conferred by the 4-HBA mediated upregulation of the transcription factor nuclear factor E2-related factor 2 (Nrf2), peroxiredoxin 6 (Prdx6) and protein disulfide isomerase (PDI) by the use of 4-HBA. Interestingly, LY294002, a phosphatidylinositol 3-kinase (PI3K) inhibitor, blocked the increase in phosphorylation of Akt and abolished the neuroprotection associated with 4-HBA. Our results suggested that 4-HBA protects neurons against cerebral ischemic injury, and this neuroprotection may occur through upregulation of Nrf2, Prdx6, and PDI expression via the PI3K/Akt pathway.