The Mechanism Study Of Trans-2,4-dimethoxystibene (S3) Anti-Alzheimer's Disease In Animal Model

S3 is a synthetic analogue of Stilbenes containing extract-fraction from Cajanus cajan L (sECC).sECC have many pharmacologic effects,Our laboratory found that sECC had hypocholesterolemic effects,estrogenic activity and anti-oxidative effects.Hence,we hypothesize that S3 could possibly has the same pharmacologic effects just as sECC.1.Protective effects of S3 on SH-SY5YIn the present study,we identified the protective effect of S3 on the injury of SH-SY5Y cells induced by H₂O₂ or Aβ_25-35.SH-SY5Y Cells were treated with S3 for 2 hours and then incubated with H₂O₂ or Aβ_25-35,the cell viability and apoptosis are analyzed by MTT assay,flow cytometric DNA analysis and Hoechst3342 staining.After treated with S3,SH-SY5Y cells survival rates were increased,the apoptosis were alleviated,and this protection was associated with reduction of reactive oxygen species and stabilization of mitochondrial membrane potential.At the same time,the estrogen receptor inhibitor ICI₁₈₂₇₈₀ can't block the effect of S3 on the increasing of SH-SY5Y cells survival.So the protective effect of S3 on the injury of SH-SY5Y cells induced by H₂O₂ and Aβ_25-35is not via to estrogen receptor.2.Protective effects of S3 on Aβ_25-35 induced cognitive deficits in miceS3 is a novel synthetic analogue of the stilbenes containing extract-fraction from Cajanus cajan L(sECC).In the present study,we identified the effects of S3 on Aβ_25-35-induced cognitive deficits,oxidative stress and cholinergic dysfunction.Mice were treated with S3 (50 mg/kg/day and 25 mg/kg/day) for one week,and then received a single intracerebroventricular(i.c.v) injection of Aβ_25-35(5μg/mice).Behavioral changes and neuron apoptosis in mice were evaluated using Morris water maze and Tunel tests. Furthermore,superoxide dismutase(SOD),choline acetyl transferase(ChAT) and acetylcholine esterase(AchE) activity in hippocampus and cortex were analyzed by spectrophotometric method.The consumption of S3 significantly ameliorated the cognitive deficits and neuron apoptosis caused by i.c.v injection of Aβ_25-35.Compared with model group,the decreased SOD activity in hippocampus and cortex were markedly increased by S3(50mg/kg) by 39.0%,45%(P＜0.01).At the same time,the ChAT activity in hippocampus and cortex were also increased by 39.5%and 55.3%(P＜0.01).After treated with S3,the AchE activity in hippocampous and cortex decrease significantly (P＜0.05).These findings suggest that S3 may be a potential candidate for development as therapeutic agent to manage cognitive impairment associated with condition such as Alzheimer's disease through increasing the activity of ChAT and anti-oxidative mechanism.3.Protective effects of S3 on Aβ_25-35 induced cognitive deficits in hypercholesterolemia ratIn this part,we evaluate the protective effect of S3 on the injury of Aβ_25-35 intracerebroventricular(i.c.v) injection in hypercholesterolemia rat.The rat feed with hypercholesterolemic chow for 45 days,then received a single intracerebroventricular (i.c.v) injection of Aβ_25-35(10μg/rat) and treatment with S3(50 mg/kg/day,25 mg/kg/day and 12.5 mg/kg/day).Behavioral changes and neuron apoptosis in rat were evaluated using Morris water maze,Step Down test and TUNEL test.The consumption of S3 (50mg/kg) significantly ameliorated the cognitive deficits and neuron apoptosis cansed by i.c.v injection of Aβ_25-35.To further explore the mechanism of S3,superoxide dismutase(SOD),GSH-PX,MDA,choline acetyl transferase(ChAT) and AchE activity in hippocampus were analyzed by spectrophotometric method,at the same time,the releases of cyto-c were analyzed by WB,and the level of Ach was analyzed by Elisa.After treated with S3,the activity of ChAT,SOD,GSH-PX and Ach in hippocampous increased significantly compared with model group,while the activity of AchE,the level of MDA and the release of cyto-c decreased markedly.These finding suggest that S3 may be a potential candidate for development as therapeutic agent to treat with AD through regulating the cholinergic nerve system and anti-oxidative mechanism.At the same time, Diet-induced hypercholesterolemia rat had been used for the assessment of S3 with beneficial effects on cholesterol metabolism.The levels of TG,TC,LDL-C and HDL-C in serum were detected.After 4 weeks treatment with S3,the increased serum TC and LDL-C were markedly attenuated,and the increased HDL-C were increased more.4.The effect of S3 on the expression of AQP1,AQP4 in hippocampous and cortex of ovariectomy rat The effect of S3 on the expression of AQP1,AQP4 in hippocampous and cortex of ovariectomy rat was investigated.After 12 weeks treatment with S3,the decreased serum E₂ was increased significantly,meanwhile the increased serum FSH,LH,and the expression of AQP1,AQP4 in hippocampous and cortex were attenuated.5.Safety evaluation of S3Acute toxicity and side reaction of S3 were investigated.Intragastric administration of S3 reached to 10g/kg/d is safe,and treatment with S3 inhibited the breast cancer cell MCF-7 proliferation.In summary,S3 may be a potential candidate for development as therapeutic agent to manage cognitive impairment associated with condition such as Alzheimer's disease or be a promising drug for the hypercholesterolemia and atherosclerosis.