Curcumin Alleviates Cerebral Ischemia-reperfusion Injury by Inhibiting NLRP1-dependent Neuronal Pyroptosis

Background: Cerebral ischemia-reperfusion injury is caused by a blood reperfusion injury in the ischemic brain and usually occurs in the treatment stage of ischemic disease, which can aggravate brain tissue injury. Objective: Curcumin was reported to exert a good therapeutic effect on neural cells against ischemia- reperfusion injury, However, the mechanism is not clear. Methods: In this study, Oxygen-Glucose Deprivation (OGD) model of fetal rat cerebral cortical neurons and the Middle Cerebral Artery Occlusion (MCAO) model of rats were employed to mimic cerebral ischemia-reperfusion injury in vitro and in vivo, respectively. Results: We confirmed that curcumin has a promotive effect on neuronal proliferation and an inhibitory effect on neuronal pyroptosis. Furthermore, we found that curcumin could improve cerebral infarction. The results of western blotting showed that curcumin down-regulated the expression of nucleotide-binding oligomerization domain-containing protein-, leucine-rich repeats-, and pyrin domain-containing protein 1 (NLRP1), cysteinyl aspartate-specific protease 1 (caspase-1), gasdermin D (GSDMD), IL-1β, IL-6, TNF-α, and iNOS proteins in OGD and MCAO models. NLRP1- dependent neuronal pyroptosis played an important role in cerebral ischemia-reperfusion injury. Conclusion: Curcumin could effectively inhibit NLRP1-dependent neuronal pyroptosis by suppressing the p38 MAPK pathway and therefore exerted neuroprotective effects against cerebral ischemia- reperfusion injury.