Protective Effect And Mechanism Of Xuesaitong On Cerebral Ischemia-reperfusion In Rats Through Nrf2 Pathway

Ischemic stroke is the second leading cause of death in the world,and the first cause of death and disability for adults in China.It is also one of the important causes of poverty caused by illness and returning to poverty due to illness in China.At present,the commonly used drugs are mainly thrombolytic,anticoagulant and hypolipidemic,but the clinical effect is not ideal.The main component of Xuesaitong injection is the total saponin of the traditional Chinese medicine notoginseng,which has the effect of promoting blood circulation,removing blood stasis and activating blood vessels and collaterals.It has been shown that Xuesaitong has anti apoptosis and anti-oxidation effects,but the specific mechanism is not clear.Objective:To study the protective effect and mechanism of Xuesaitong on focal cerebral ischemia from the perspective of oxidative stress,and to provide important theoretical and experimental basis for the effective treatment of cerebrovascular diseases.Methods:1.To establish MCAO model: Wistar rats were randomly divided into 5 groups: sham operation group,MCAO group,small dose group(2.5mg / kg),medium dose group(5mg / kg)and large dose group(10mg / kg).In sham operation group and MCAO group,normal saline was given continuously for one week,and Xuesaitong injection was given continuously for one week,then the MCAO model was reproduced by thread bolt method(ischemia for 2 hours and reperfusion for 24 hours).2.Zea-longa method was used to evaluate the neurobehavioral score and detect the neurological deficit in rats.3.TTC staining was used to detect the area of cerebral infarction in rats.4.HE staining was used to detect the degree of cortical injury in rats.5.RT-PCR and Western blot were used to detect the expression of apoptosis related genes and proteins in cerebral cortex.6.SOD and MDA kits were used to detect the level of oxidative stress in cerebral cortex.7.Western blot and RT-PCR were used to detect the expression of KEAP1 and NRF2 protein and the expression of nqo1,gclm and ho1 mRNA.Results:1.The results of Zea-longa neurobehavioral score showed that the neurobehavioral score of MCAO group was significantly higher than that of sham operation group,and the neurobehavioral score of Xuesaitong group was significantly lower than that of sham operation group.2.TTC staining showed that compared with the sham operation group,the MCAO group had a pale infarct area,and the infarct area was significantly increased,while the Xuesaitong group had a significantly reduced infarct area.3.HE staining showed that the neurons in MCAO group were pyknosis triangle,hyperchromatic and the number of neurons decreased.However,the number of neurons with ischemic characteristics in Xuesaitong group decreased significantly.4.In MCAO group,the expression of bcl-2 mRNA and protein decreased,bax mRNA and protein increased,caspase3 mRNA and protein increased significantly.Xuesaitong can significantly promote the expression of bcl-2 mRNA and protein,inhibit the expression of bax mRNA and protein,and significantly reduce the expression of caspase3 mRNA and protein,indicating that Xuesaitong can significantly reduce the apoptosis of cerebral cortex.5.In MCAO model group,the content of MDA in cerebral cortex increased significantly,while the activity of SOD decreased significantly.The MDA content and SOD activity of Xuesaitong group decreased significantly,indicating that Xuesaitong can scavenge free radicals and has antioxidant effect.6.In MCAO group,the expression level of KEAP1 protein was significantly increased,while that of NRF2 protein was significantly decreased,and the expression level of nqo1,gclm and ho1 mRNA of downstream target gene was significantly decreased;in Xuesaitong group,the expression level of KEAP1 protein was significantly decreased,and that of NRF2 protein was significantly increased,and the expression level of nqo1,gclm and ho1 of downstream target gene was significantly increased.The expression level of mRNA was significantly increased,indicating that Xuesaitong may play an antioxidant role through the recovery of Keap1-Nrf2 signal pathway.Conclusions:1.Xuesaitong can obviously reduce the brain damage caused by ischemia-reperfusion injury,and has the brain protective effect.2.The mechanism of Xuesaitong’s brain protection may be to activate keap1-nrf2 signal pathway and play an antioxidant role.