Propranolol alleviates cerebral infarction through the β2-AR-mediated ERK/NLRP3 pathway

Propranolol, a non-selective β-adrenergic receptor (β-AR) blocker, has been shown to reduce brain infarction in mice following ischemic stroke. Transient middle cerebral artery occlusion (tMCAO) mice and BV2 cells subjected to oxygen-glucose deprivation (OGD) were used to assess pathophysiological changes after ischemic stroke through behavioral, biochemical, and pathological analyses. We found that propranolol alleviated brain injury after cerebral infarction, inhibited microglial activation, and reduced the expression of NLRP3 and IL-1β. It also reduced Evans blue (EB) extravasation and enhanced the expression of Occludin, ZO-1, and CD-31. Compared to the tMCAO group, all these pathological changes could be reversed in NLRP3^-/- mice. Similar results were also observed in the OGD model, where blockade of β2-AR decreased the expression of p-ERK1/2 and NLRP3 in BV2 cells. Furthermore, U0126 treatment also lowered NLRP3 and IL-1β levels. These results demonstrated the important role of β2-AR signaling in regulating the inflammatory response in ischemic stroke.