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Aim To investigate the influence of echi-nacoside ( ECH ) on monoaminergic neurotransmitter extracellular of the hippocampus and cerebral cortex in rat model of Alzheimer′s disease ( AD) , and ultimately to provide a theoretical basis for ECH′s improving the ability of learning and memory. Methods 60 male SD rats were randomly divided into 6 groups with 10 rats in each group : sham operation group, model, ECH groups of low, medium and high doses (10, 20, 40μg ·g-1 ·d-1 ) , and Hup A ( Huperzine A, 0. 02 μg· g-1·d-1) group. The AD rat model was established by abdominal cavity injection with D-galactose and uni-laterally injected with amyloid beta-protein fragment 25-35 ( Aβ25-35 ) into the right hippocampus. Morris wa-ter maze test was used to study the animals′ ability of spatial learning and memory. The synchronous dual-probe dual-channel brain microdialysis sampling tech-nology was applied to collect dialysates from different encephalic areas continuously, and combined with HPLC electrochemical detection were used to measure the extracellular levels of norepinephrine ( NE) , dopa-mine (DA), 5-serotonin (5-HT). Results 1. Com-pared with the sham operation group, the mean escape latency of the model group was significantly prolonged ( P<0. 05 ) , and the time that rats were in the plat-form quadrant was significantly shortened ( P<0. 05 );on the contrary, compared with the model group, the mean escape latency of ECH groups were significantly shortened ( P<0. 05 ) , and the time that rats were in the platform quadrant was significantly extended ( P<0. 05). 2. Compared with the sham operation group, the contents of NE,DA and 5-HT were significantly de-creased in the model group ( P <0. 05 ) . However, compared with the model group , ECH could improve the concentrations of NE, DA, 5-HT in the hippocam-pus and cerebral cortex, and these monoamine levels of the brain regions were restored to near control. Con-clusion ECH can effectively improve the ability of learning and memory of rats with AD, giving a rise to the monoamine neurotransmitter both in hippocampus and cortex, exerting a positive effect on treatment of cognitive dysfunction . The ECH low dose group is sig-nificantly lower than the ECH groups of medium and high doses and Hup A group in improving the ability of learning and memory.
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Aim To investigate the protective effects of echinacoside ( ECH ) on oxidative stress injury in vascular dementia rats. Methods Vascular dementia model was duplicated by means of permanent ligation of bilateral common carotid artery at two times intervals for three days. Biochemical methods was used to detect the GSH, NO, GSH-Px, NOS in each group rat’ s cor-tex and hippocampus. The change of the tissue struc-ture in CA1 area of hippocampus in each group was ob-served and analyzed by microscope after HE staining. Results Compared with sham group, the content of GSH and activity of GSH-Px in the rats of the model group were decreased significantly ( P0. 05 ) . Conclusion ECH exerts protection on oxida-tive stress injury in vascular dementia rats.
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Aim To investigate the effects of echina-coside ( ECH ) on the learning and memory capacities and brain level of oxygen free radicals of rats with de-mentia induced by amyloid β-peptide. Methods Six-ty Sprague Dawley rats, weighing (300±10) g, were randomly divided with 10 rats pergroup into 6 groups:sham operated group, model, ECH high dose (40 mg ·kg-1·d-1), ECH middle dose (20 mg· kg-1· d-1), ECH low dose (10 mg·kg-1·d-1) and Hup A (Huperzine A, 0. 02 mg·kg-1·d-1) group. Mor-ris maze tests were conducted for evaluating the learn-ing and memory ability. Content of malondialdehyde (MDA), nitric oxide (NO) and activities of superox-ide dismutase ( SOD) and NO synthase ( NOS) in the hippocampus and cortex were detected. ResultsAβ25-35 induced significant learning and memory im-pairment in the rats. Compared with the rats in model group, those treated with ECH at different doses all manifested alleviation of learning and memory impair-ment ( P<0 . 01 , P<0 . 05 ) . Cotents of MDA of ECH treatment group were obviously decreased, while SOD activities were obviously increased, and significantly reduced the release of NO and NOS in the hippocam-pus and cortex brain tissue ( P <0 . 01 , P <0.05 ) . Conclusion ECH can enhance the learning and mem-ory ability in rats with AD, which is presumably relat-ed to accelerating the cleaning of oxygen free radicals and reducing oxidative stress in brain of AD rats.
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Aim Tostudytheeffectsofechinacoside on striatal and hippocampus extracellular fluid of mono-amine neurotransmitter in Parkinsonˊs disease rat, and discuss the possible mechanism of the ECH effect on brainprotection.Methods Doublepointinjectionof 6-hydroxy dopamine damaged was adopted to make PD model, the corresponding drugs or normal saline were intraperitoneally injected for 4 consecutive weeks, mi-cro-dialysis program in double targets was taken after treatment, the dialysate was injected into HPLC-EDC, and striatal and hippocampus extracellular fluid of DA, DOPAC, HVA, NA, 5-HT levels of each group were measured. Results Compared with control group, striatal and hippocampus extracellular fluid of DA, DOPAC, HVA, NE, 5-HT levels were significantly re-duced in model group ( P <0. 01 ); compared with model group, striatal and hippocampus extracellular fluid of DA, DOPAC, HVA, NE, 5-HT levels were significantly increased in treatment group ( P <0 . 05 , P<0. 01 ) , and the content of five kinds of substances in ECH high dose group was similar to that in MD group.Conclusion ECHcouldincreaseextracellular monoamine neurotransmitters in striatum and hippo-campus, ECH has a therapeutic effect on PD, and echinacoside is possible mechanisms of the brain pro-tective effect of PD rats.
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OBJECTIVE Toexplorethecredibityoftwoimprovedmodelsofsyntheticvascular dementia(VD)rats.METHODS OneimprovedmodelofVDratswasestablishedbyligatuingthebilat-eral common carotid artery twice at 3 d (improved 2-VO),while the other was established by blocking the middle cerebral artery on the left side by separating pterygopalatine arteria (i mproved MCAO/R). The learning and me mory ability was determined by escape latency in Morris water maze directional navi-gation test and cross-over ti mes in target areas in spatial probe test and the search strategy.The organi-zational structure in CA1 area of the hippocampus was observed and analyzed under a microscope after HEstaining.RESULTS Thelearningandmemoryabilitydecreasedsignificantlyin2modelgroupsat 20 d after the operation.The escape latency was much longer in improved 2-VO group and improved MCAO/R group than that in sham group(P<0.05)especially in improved 2-VO group.41 d after the operation,no difference between MCAO/R and sham group (P <0.05 ).The differences between improved 2-VO group and sham group remained significant(P<0.01 ),and difference between improved 2-VO group and improved MCAO/R group was significant(P<0.01 )at 41 d.The cross-over times in the target area in spatial probe test decreased more significantly in 2 model groups than in sham group. 41 d after the operation,improved MCAO/R group was not different from sham group(P<0.05). Search strategy results showed that swimming trajectory in the improved 2-VO groupwas mostly edge and random type,but was of tendency type and straight type in the improved MCAO/R group.In the organization structure of hippopal CA1 area of rats,the nu mber of cells was reduced,their arrange ment was sparse and chaotic,the morphology of cells was inco mplete,the structure of cells was abnormal, cytoplasmwasscarce,andnucleoliwereinconspicuous.CONCLUSION TwoimprovedVDmodelscan lead to behavior and pathological changes in rats.The i mproved 2-VO model,si mple and stable,is suitable for drug efficacy research.The improved MCAO/R model is the ideal short-term efficacy study.
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The aim of this study is to investigate the effect of echinacoside (ECH) on cholinergic neurotransmitter extracellular of hippocampus and striatum and its possible mechanisms of neuro-protective effect against vascular dementia rats. In this study brain microdialysis technique combined with HPLC-IMER-ECD (high-performance liquid chromatography-immobilized enzyme reactor-electrochemical detector) was used. The bilateral common carotid arteries occluded in two times operation at 72 h interval for vascular dementia model rats were used and the successful vascular dementia model rats were examined by Morris water maze. The content of acetylcholine (ACh) and choline (Ch) of microdialysate extracellular of hippocampus and striatum was determined by HPLC-IMER-ECD and the AChE activity in the hippocampus was measured. The results showed that the success rate of vascular dementia model was 83.08% after six weeks; the results also showed that echinacoside and galantamine could increase the content of ACh and reduce the content of Ch extracellular of hippocampus and striatum significantly and the AChE activity increased significantly compared with that of the model group. The results suggested that echinacoside could promote the recovery of cholinergic neurotransmitter levels in vascular dementia rats' brain, which may be one of the mechanisms of neuro-protection.