Studys On Protective Effects Of Panax Quinquefolium Saponins From Steams And Leaves On Focal Cerebral Ischemia Demage In Rats

Objective:To investigate the protective effects of Panax quinquefolium saponins from steams and leaves(PQS)on focal cerebral ischemia damage and its mechamism.Methods:1.The male rats were pretreated with PQS 50 and 100 mg·kg^-1ig,one time per day for 7d,and then subjected to focal cerebral ischemia damage induced by a middle cerebral artery occlusion(MCAO)for 24h.The following indexes were determined:(1)The neurological deficit, pathological change and infarct scope were deterinimed by Longa's score, optical and electric microscope,and TTC staining;(2)The activity or content of LDH,LA,SOD,MDA,NOS and NO in the ischemic cerebral tissues were detected by colorimetric method;(3)TUNEL labeling and flow cytometry were used for determination of the cortical neuronal apoptosis,the expression of Bcl-2,Bax and Caspase-3 mRNA and protein in the cortical neuron were detected with immunohistochemical method and reverse transcription polymerase chain reaction(RT-PCR).2.PC12 cells were cultured with PQS(40,100,250μg·mL^-1)in vitro and treated with sodium dithionite in glucose-free medium,glutamic acid, H₂O₇ and sodium nitroprusside.The activity of LDH in the medium and the vitality of the cells were measured by colorimetric method and MTT method,the morphological change was observed by the upside down discrepancy microscope.The activity or content of SOD or NOS,MDA or NO of the cells subjected to being deprived glucose and oxygen or treated with glutamic acid were detected by colorimetric method.3.PC12 cells were cultured with PQS(40,100,250μg·mL^-1)in vitro and treated with sodium dithionite in glucose-free medium,glutamic acid,KCI, A23187 and caffeine,the intracellular free Ca²⁺concentration([Ca²⁺]i) was measured by Fura-2 fluorescence technique. Results:1.PQS significantly ameliorated the neurological deficit,reduced imfarct scope and improved the pathological changes.2.PQS significantly increased the activity of LDH and SOD and decreased the activity or content of NOS,LA,MDA and NO in the ischemic cerebral tissues.3.PQS significantly decreased the apoptosis of neural cells,increased the expression of Bcl-2 mRNA and protein,reduced the expression of Bax and Caspase-3 mRNA and protein and increased Bcl-2/Bax expression ratio.4.PQS significantly improved morphological features,increased the vitality of cells and decreased the activity of LDH of the cells which were subjected to depriving glucose and oxygen or treated with glutamic acid, H₂O₂ and sodium nitroprusside.Meanwhile,PQS significantly increased the activity of SOD,decreased the content of MDA and NO of the cells subjected to being deprived glucose and oxygen,and the activity of NOS and the content of NO of the cells treated with glutamic acid were significantly decreased by PQS.5.PQS significantly decreased[Ca²⁺]i of the cells subjected to being deprived glucose and oxygen or treated with glutamic acid,KCl,A23187 and caffeine.Conclusion:PQS has protective effects on focal cerebral ischemia damage and its mechanism may be related to resist oxidative damage,reduce acidosis and the cytotoxic action of NO,depress cell apoptosis through affecting the expression of the apoptosis-related genes,resist the damage induced by the toxic product in ischemia cascade reaction such as excitatory amino,free radical and NO,and inhibit calcium overload induced by virous agent.