Protective effects of oridonin against cerebral ischemia/reperfusion injury by inhibiting the NLRP3 inflammasome activation

NOD-like receptor protein 3 (NLRP3) inflammasome is tightly related to the pathogenesis of cerebral ischemia/reperfusion (I/R) injury, and oridonin (Ori) has shown the potential to alleviate ischemia/reperfusion injury with underlying mechanisms. Our study aims to figure out whether Ori protects against the cerebral ischemia/reperfusion injury by the NLRP3 inflammasome signaling. In this study, a temporary middle cerebral artery occlusion (MCAO) and reperfusion surgery was conducted on male C57BL/6 mice to mimic cerebral I/R injury in vivo. Cellular model of cerebral I/R in vitro was achieved by oxygen-glucose deprivation and reintroduction (OGD/R) in BV2 microglia cells. We found that Ori treatment significantly relieved the neurological deficits, neuronal injury and microglia activation in I/R mice according to morphological and histological analyses. Meanwhile, the inactivation of NLRP3 inflammasome was determined in Ori-treated mice with significantly down-regulated expressions of inflammasome-related genes. Western-blot analysis further demonstrated the negative effect of Ori on NF-kappa B signaling with diminished phosphorylation and degradation of I kappa B alpha as well as suppressed translocation of p65. Furthermore, we indicated that Ori suppressed the activation of NLRP3 inflammasome in OGD/R induced BV2 microglia cells by inhibiting NF-kappa B signaling. In summary, our findings make Ori a potential candidate for therapy of cerebral I/R injury in the future.