Isosteviol Sodium Protects against Ischemic Stroke by Modulating Microglia/Macrophage Polarization via Disruption of GAS5/miR-146a-5p sponge

Recent studies have shown that transforming microglia phenotype from pro-inflammation of M1 phenotype to anti-inflammation and tissue-repairing M2 phenotype may be an effective therapeutic strategy for preventing ischemic stroke brain injury. Isosteviol Sodium (STV-Na) has shown promise as a neuroprotective agent in cerebral ischemia model, although its effect on microglial polarization and chronic recovery after stroke is not clear. Here, we demonstrated that STV-Na treatment significantly reduced cerebral ischemic damage at both acute and chronic time points. STV-Na has a profound regulatory effect on microglia response after stroke. It can promote M2 polarization and inhibit microglia-mediated inflammation (M1) response following stroke in vivo and in vitro. Furthermore, we also found that Growth Arrest-Specific 5 (GAS5) altered OGD/R-induced microglial activation by increasing Notch1 expression via miR-146a-5p, the mRNA level of GAS5 and the protein level of Notch1 in vivo and in vitro, were discovered that both downgraded with STV-Na. Taken together, the present study demonstrated that STV-Na exerted neuroprotective effects by modulating microglia/macrophage polarization in ischemic stroke via the GAS5/miR-146a-5p sponge. These findings provide new evidence that targeting STV-Na could be a treatment for the prevention of stroke-related brain damage.