15, 16-Dihydrotanshinone I protects against ischemic stroke by inhibiting ferroptosis via the activation of nuclear factor erythroid 2-related factor 2

Nuclear factor erythroid 2-related factor 2 (Nrf2) is a key regulator of antioxidative stress responses, which are associated with ferroptosis inhibition. Ferroptosis is closely related to the pathophysiological process of ischemic stroke. 15, 16-Dihydrotanshinone I (DHT), a lipophilic tanshinone extracted from the root of Salvia miltiorrhiza Bunge (Danshen), has various pharmacological effects. However, its effect against ischemic stroke remains to be examined. This study aimed to investigate the protective effect of DHT against ischemic stroke and its underlying mechanism. Rats with permanent middle cerebral artery occlusion (pMCAO)-induced cerebral ischemia rats and tert-butyl hydroperoxide (t-BHP)-injured PC12 cells were used to investigate the protective effect of DHT against ischemic stroke effect and the potential mechanism. The results showed that DHT decreased ferroptosis in-vitro experiment, as indicated by decreased lipid ROS generation, increased Gpx4 expression and the ratio of GSH/GSSG, and improved mitochondrial function. The inhibitory effect of DHT on ferroptosis was decreased after Nrf2 silencing. Furthermore, DHT decreased the neurological score, infarct volume, and cerebral edema, increased regional cerebral blood flow, and improved the microstructure of white-grey matter in pMCAO rats. In addition, DHT activated Nrf2 signaling and inhibited ferroptosis marker events. Nrf2 activator and ferroptosis inhibitor also exerted protective effects on pMCAO rats. These data demonstrated that DHT might have therapeutic potential for ischemic stroke and protects against ferroptosis via the activation of Nrf2. This study provides new insight into DHT-mediated prevention of ferroptosis in ischemic stroke.