Total Flavones of Planch Flower Protect against Cerebral Ischemia-Reperfusion Injury via the Mechanism of Cystathionine--Lyase-Produced HS.

Total flavones of Planch flower (TFR) have a significant protective effect against cerebral ischemia-reperfusion injury. However, its mechanism is unclear. This study investigated the protection of TFR against cerebral ischemia-reperfusion injury via cystathionine--lyase- (CSE-) produced HS mechanism. CSE mice and CSE-siRNA-transfected rat were used. Relaxation of cerebral basilar artery (CBA), HS, and CSE mRNA were measured. TFR significantly inhibited cerebral ischemia-reperfusion-induced abnormal neurological symptom and cerebral infarct in the normal rats and the CSE mice, but not in the CSE mice, and the inhibition was markedly attenuated in CSE-siRNA-transfected rat; TFR elicited a significant vasorelaxation in rat CBA, and the relaxation was markedly attenuated by removal of endothelium or CSE-siRNA transfection or coapplication of NO synthase inhibitor L-NAME and PGI synthase inhibitor Indo. CSE inhibitor PPG drastically inhibited TFR-evoked vasodilatation resistant to L-NAME and Indo in endothelium-intact rat CBA. TFR significantly increased CSE mRNA expression in rat CBA endothelial cells and HS production in rat endothelium-intact CBA. The increase of HS production resistant to L-NAME and Indo was abolished by PPG. Our data indicate that TFR has a protective effect against the cerebral ischemia-reperfusion injury via CSE-produced HS and endothelial NO and/or PGI to relax the cerebral artery.