Icaritin inhibits oxidative stress in murine astrocytes by binding to Orai1 to block store-operated calcium channel.

Previous study has shown that icaritin (ICT) has meaningful protective effect on cerebral ischemic stroke, and this study aimed to investigate its mechanism from the aspect of protecting astrocytes from oxidative stress. Murine primary astrocytes were pretreated by ICT and exposed to H O to induce oxidative stress. The results indicated that ICT inhibited H O -induced astrocytes apoptosis, decreased Bax and cleaved caspase-3, and increased Bcl-2. In addition, ICT inhibited H O -induced oxidative stress, increased mitochondrial membrane potential (ΔΨ ), and maintained mitochondrial morphology. ICT decreased the synthesis of malondialdehyde and increased the activity of glutathione peroxidase, catalase, and superoxide dismutase. Moreover, ICT suppressed the transient and resting intracellular Ca overload. Further investigation revealed that ICT could target the combination with Orai1 to block store-operated calcium channel induced by H O . However, ICT did not enhance the protective effect of RO2959, a selective blocker of Orai1. These results indicate that ICT can play a neuroprotective role against oxidative stress injury by binding to Orai1 to block SOCC.