Oleanolic Acid Alleviates Neuronal Ferroptosis in Subarachnoid Hemorrhage by Inhibiting KEAP1-Nrf2 and NF-κB Pathways

Oleanolic acid (OA) is a pentacyclic triterpenoid compound, and we previously report that it ameliorates neurological injury in subarachnoid hemorrhage (SAH) model. However, the underlying mechanism is not clear. The aim of this study was to explore the effect and mechanism of OA on SAH. In this study, network pharmacology was applied to screen the targets of OA in SAH treatment. Based on these targets, protein-protein interaction network was constructed, and k-means cluster analysis was used to screen the core targets of OA in SAH treatment. In vitro SAH model was constructed with hemin-induced neuron HT22 and microglia BV2. Then cell counting Kit 8, flow cytometry, western blot, qPCR were performed to evaluate the effects of OA on neurons and microglia. 93 targets were identified as the core targets of OA in SAH treatment. Notably, these targets are closely related to neuroinflammation and oxidative stress responses. OA had good binding activity with KEAP1, NFKB1 and IKBA. OA significantly alleviated the inhibitory effect of hemin on HT22 cell viability. OA significantly inhibited the expression of CD86, promoted the expression of CD206, and promoted the transformation of microglia from M1 type to M2 type. Additionally, OA could inhibit the activation of NF-κB and KEAP1/Nrf2 pathways. In conclusion, OA ameliorates inflammatory response, oxidative stress and ferroptosis in SAH, and suppresses neuronal injury by inhibiting NF-κB and KEAP1/Nrf2 pathways.