Study On The Protective Effect And Mechanism Of Longxuetongluo Capsule Against Cerebral Ischemia/Reperfusion Injury

Stroke is one of the most fatal desease in the world,especially in China,which seriously endangers human life and health.Among them,ischemic stroke has the highest morbidity.Currently,the treatment of ischemic stroke is mainly based on thrombolytic therapy with drugs or operation to achieve vascular recanalization.However,since the attacked by the excessive free radical,more sever damage and cell apoptosis occurred to the brain tissue after blood supply reestablishment,which is called cerebral ischemia/reperfusion injury.Cerebral ischemia/reperfusion injury refers to the phenomenon of tissue injury aggravation after cerebral thrombolytic therapy.Cerebral ischemia/reperfusion injury can cause necrosis or apoptosis of tissue cells in various forms.Among them,in addition to the mitochondrial-related apoptosis,the endoplasmic reticulum stress(ER stress)induced cell apoptosis has been attracted more and more attention as a lately discovered mechanism in recent years.Chinese Dragon’s Blood,the red resin from Dracaena cochinchinensis(Lour.)S.C.Chen,has been used to promote blood circulation,relieve pain,alleviate blood stasis and swelling,and stop bleeding.Many scholars have discovered that the main effective components contained in Chinese Dragon’s Blood are the phenolic compounds.These compounds have the broad activities of cerebral.ischemic protection,anti-thrombotic,anti-inflammatory,antioxidant,anti-platelet aggregation and blood rheology regulation activity.According to the TCM theory,Longxuetongluo Capsule(LTC),which contitains the total phenolic extract of Chinese Dragon’s Blood as its main active ingredient,was our own new drug for the treatment of blood stasis in the convalescence of ischemic stroke,which has had exact clinical efficacy.However,the mechanism of its protective effect against cerebral ischemia-reperfusion injury is still unclear.In this study,the oxygen glucose deprivation/reoxygenation(OGD/R)in vitro model was applied for the simulation of cerebral ischemia/reperfusion injury.PC 12 cells and HUVEC cells were adopted to simulate nerve cells and brain vascular endothelial cell unit fot the study of the protective effect of Longxuetongluo Capsule against cerebral ischemia/reperfusion injury and the up-stream mechanism.Then the middle cerebral artery occlusion(MCAO)model was applied for the study of the therapeutic effect of Longxuetongluo Capsule in vivo against cerebral ischemia/reperfusion injury and the undefined mechanism,which aimed to verified the results of the in vitro experiments.The purpose of this study is to elucidate the mechanism of the protective effect of Longxuetongluo Capsule against cerebral ischemia/reperfusion injury,and provide reference for its clinical application and research.The main achievements are follows.1.Longxuetongluo Capsule protected PC 12 and HUVEC cells against OGD/R injury by improving cell viabilities and decreasing LDH release.Cell apoptosis of PC 12 cells after OGD/R treatment was inhibited by LTC via the inhibition of PERK-eIF2a-CHOP signaling pathway-mediated ER-stress and the down-stream MAPK signaling pathwy.The inhibition of cell apoptosis of HUVEC was exerted via the inhibition of mitochondria-related Caspase-3/9 pathway.The result in vivo revealed that the infarct size of the brain tissues of rats after MCAO were markedly reduced by LTC treatment,and the integrity of nerve cells was also well protected by LTC.Further investigation reflected that the apoptosis of nerve cell was inhibited by LTC via the down-regulation of CHOP expression,which indicated that it is possible that Longxuetongluo Capsule exerted its protective effect against cerebral ischemia/reperfusion injury by inhibiting ER stress-induced apoptosis in nerve cells.These results implied the following conclusions.Longxuetongluo Capsule exerted its protective effect in vivo against cerebral ischemia/reperfusion injury by reducing infarct size of brain tissue,protecting the integrity of nerve cells and inhibiting cell apoptosis.Meanwhile,Longxuetongluo Capsule has protective effect against OGD/R injury in PC 12 cells and HUVEC cells via respectively inhibiting ER stress-induced apoptosis and mitochondria-related Caspase-3/9 pathway.And eventually,we clarified the up-stream mechanism of the protective effect of Longxuetongluo Capsule against cerebral ischemia/reperfusion injury,and provided soild reference for its clinical application.