The Roles Of Ginsenoside Rg1 And Underlying Mechanism In The Protective Effects On The Injury Caused By Cerebral

Purpose:To explore the roles and underlying mechanism of ginsenoside Rg1 in the protective effect on the injury caused by cerebral ischemic-reperfusion. Materials and methods:Healthy male Sprage-Dawl rats(250-300 g) were randomly divided into the sham-operative group(sham group),focal cerebral ischemia-reperfusion group(model group),Ginsenoside Rg1 treated group,and Nimodiping treated(1mg/kg) group(n=35 in each group).The Rg1 treated group was further divided into three subgroups according to the Rg1 dosage(10,20, 40mg/kg).The middle cerebral artery occlusion model(MCAO 6 h,24 h) was established by suture method.Rg1(10,20,40mg/kg respectively) was injected as follows:5 days before operation,at the day of operation,24 h after operation (q.d),positive control group(1mg/kg)was injected in Nimodiping group(1mg/kg), NS was injected in the same time point in Sham group and Model group.24 h after operation,the neurological function was evaluated by neurological deficit scoring.Then the rats were sacrificed and the volume change of cerebral infarction was examined by TTC staining,the moisture of brain tissue was detected by dry-wet weight assay,morphological changes in hippocampus CA1 zone were observed by HE staining,the neuron apoptosis status in hippocampus CA1 zone was detected by TUNEL assay,the ultramicrostructure of neurons in hippocampus CA1 zone was detected by transmission electric microscopy,the numbers of neuron was detected by nissle staining.The expression of Bcl-2,Bax,FAS and FAS-L were analyzed by immunohistochemistry and wstern blot.After 6h of focal cerebral ischemia,the expression of p-JNK and p-c-jun were detected by immunohistochemistry staining and wstern blot.Results:1.Compared with model group,the symptoms of neurological deficit were differentially improved in Ginsenoside Rg1 treated group after 24 h of MCAO. 40 mg/kg subgroup was more significant than 10,20 mg/kg subgroup(P＜0.05). Volumes of cerebral infarction were significantly decreased in Rg1 treated group compared with model group.40mg/kg subgroup was more evident(P＜0.05).Moisture of brain tissue was significantly decreased in 20,40 mg/kg subgroups after 24 h of MCAO.40mg/kg subgroup was more evident(P＜0.05),while the difference between 10mg/kg and model groups is not significant.Compared with model group, cells arranged in order,the extent of edema of interstitial and neurons were decreased in hippocampus CA1 zone in Ginsenoside Rg1 treated group after 24 h of MCAO.Rg1 40 mg/kg subgroup was more evident(P＜0.05),while the difference between 10 mg/kg and model groups is not significant.2.Compared with model group,apoptosis rate of neuron in hippocampus CA1 zone was significantly decreased in 20,40mg/kg subgroups after 24h of MCAO.40mg/kg subgroup was more evident(P＜0.05).Apoptotic neurons of different period were observed in hippocampus CA1 zone in model group,a few viable apoptotic cells were observed in hippocampus CA1 zone in Ginsenoside Rg1 treated group after 24 h of MCAO.Compared with model group,the extent of rER edema in hippocampus CA1 zone was decreased,and the extent of crista mitochondria fracture was improved in Ginsenoside Rg1 treated group after 24 h of MCAO.Compared with model group,neuron number was more in hippocampus CA1 zone in 20,40mg/kg subgroups after 24h of MCAO,while the difference between 10mg/kg and model groups is not significant.Immunohistochemistry revealed that Bcl-2 and Bax were expressed in the cytoplasm of the neurons.Compared with model group,Bcl-2 positive cells were significantly increased.However,Bax positive cells were significantly decreased in hippocampus CA1 zone after 24 h of MCAO in Rg1 treated group.Western blot analysis verified our results of immunohistochemistry.Compared with model group,immunostaining analysis revealed the expression of FAS and FAS-L in hippocampus CA1 zone was significantly decreased after 24h of MCAO in Rg1 treated group.Western blot analysis obtained the consistent results.The differences among 20,40mg/kg and model groups were significant,but 10mg/kg subgroup was not significant.3.Compared with model group,expression of p-JNK in hippocampus CA1 zone was significantly decreased in Rg1 treated group compared with model group.40mg/kg subgroup was more evident(P＜0.05).Western blot analysis revealed the same tendency as immunohistochemistry.Expression of p-c-jun in hippocampus CA1 zone was significantly decreased in Rg1 treated group compared with model group.40 mg/kg subgroup was more evident(P＜0.05).Western blot analysis obtained the consistent results.Conclusions,1.Ginsenoside Rg1 improved obviously the neurological deficit caused by cerebral ischemic-reperfusion.2.Ginsenoside Rg1 inhibited significantly the apoptosis of neurons in ischemic zone caused by cerebral ischemic-reperfusion.Further research revealed that Rg1 suppresses the phosphorylation of JNK and c-jun,inhibits the expression of Bax,FAS,FAS-L and promotes the expression of Bcl-2.