Abstract:

Honokiol is a protective agent for cerebral ischemia injury when administered intravenously. In the present study, we aimed to investigate the oral effect of honokiol microemulsion on cerebral ischemia-reperfusion (I-R) injury in rats and stroke in SHRsp. Both tMCAO and SHRsp models in rats were used to evaluate the efficacy of the microemulsion. Rat aortic segment contraction test, primary rat aortic endothelial cells and primary brain microvascular endothelial cells (BMECs) injured by OGD-R were used to explore its potential action mechanism. Oral honokiol microemulsion significantly reduced infarct volume, neurological score and brain water content in tMCAO model, and it evidently reduced neurological score and increased the survival rate of SHRsp. Moreover, honokiol significantly inhibited aortic contraction induced by KCl and phenylephrine, and L-NAME suppressed these inhibitory effects. On the other side, honokiol increased NO and p-eNOS levels in rat endothelial cells. In addition, it also protects BMECs against OGD-R injury and increased eNOS expression in BMECs. In conclusion, oral honokiol administration has protective effects in tMCAO and in SHRsp rats, and its action mechanism is likely to be associated with its vasodilative effect produced by eNOS activation and with its protective effect on BMECs.  

Key words: Honokiol, Cerebral ischemia-reperfusion, SHRsp, Vasodilatory, eNOS