人参皂苷Rg1对β淀粉样蛋白诱导细胞凋亡的影响

目的 探讨人参皂苷Rg1对β淀粉样蛋白(Aβ)诱导细胞凋亡的影响及其机制.方法 利用中国仓鼠卵巢瘤细胞系(CHO)采用MTY方法筛选人参皂苷Rgl抗Aβ细胞毒性的有效浓度.通过转染突变型(M146L)PS1基因的CHO细胞(PS1M146L),利用免疫荧光染色、蛋白质免疫印迹方法,探讨人参皂苷Rg1对PS1M146L细胞中Aβ42和凋亡效应基因半胱氨酸蛋白水解酶(caspase-3)活性蛋白表达的影响,通过脱氧核苷酸转移酶介导的dUTP缺口末端标记法和Annexin V-FITC/PI染色流式细胞仪检测,观察人参皂苷Rg1对Aβ促细胞凋亡的影响.结果 加用25、50、100 μmol/L人参皂苷Rg1的CHO细胞活性明显高于未加用组(均P＜0.05).在转染突变型PS1M146L的CHO细胞中,加用人参皂苷Rg1作用24 h后早期细胞凋亡数(10.11.11±0.76)较未加用组(15.01±1.46)少,差异有统计学意义(P＜0.05);同时Aβ42和caspase-3活性片段的蛋白质表达量较未加用组细胞亦不同程度降低(均P＜0.05).结论 人参皂苷Rg1可能通过降低Aβ42生成和降低caspase-3蛋白质表达抑制Aβ诱导的细胞凋亡.

Ginsenoside-Rg1 inhibits cell apoptosis induced by beta amyloid

Objective To investigate the effects of ginsenoside-Rg1 on the apoptosis induced by beta amyloid (Aβ) and mechanism thereof so as to search an approach to prevent and treat Alzheimer' s disease. Methods (1) Chinese hamster ovarian tumor cells of the line CHO unable to produce endogenous Aβ were cultured and randomly divided into 3 group: control group, Aβ25-35 group treated with Aβ25-35, and ginsenoside-Rg1 and Aβ25-35 group treated with ginsenoside-Rg1 of the concentrations of 10, 12.5, 25, 50,and 100 μmol/L respectively for 12 h and then treated with Aβ25-35. MTT method was used to dete4ct the survival rate of the CHO cells. (2) Chinese hamster ovarian tumor CHO cells transfected with mutant PSIM146L gene and wild type APP751 gene (mutant PSM146L/APP751 cells) stably producing excessive Aβ1-42 and wild type PSI cells were randomly divided into groups added with ginsenoside-Rg1 of the concentration of 25 μmol/L and groups without ginsenoside-Rg1. Annexin V-FITC/PI apoptosis kit and TUNEL kit were used to detect the apoptotic cells. Immunofluorescence staining was used to detect the protein expression levels of and caspase-3 that mediates the cell apoptosis induced by Aβ. Western blotting was used to detect the protein expression of caspase-3. Results Ginsenoside-Rg1 25, 5, and 100 μmol/L dose-dependently increased the cytoactivity level of the CHO cells ( all P＜0.05 ) compared with that of the untreated cells. Annexin V-FIFC/PI test and TUNEL showed that the number of apoptotic cells of the mutant PSM146L cells was significantly higher than that off the wild type PSI cells ( P＜0.05 ), and the number of apoptotic cells of the mutant PSM146L cells treated with ginsenoside-Rg1 was significantly lower than that of the un-treated cells (P＜0.05 ), Immunofluorescence staining showed that the expression site of Aβ was consistent with that of caspase-3, the protein expression levels of Aβ42 and caspase-3 of the PS1M146L/APP751 CHO cells treated with 25 μmol/L ginsenoside-Rg1 were both significantly lower than those of the untreated PS1M146L/APP751 CHO cells (P＜0.05 ). Western blotting showed that the active caspase-3 protein expression level of the PSIM146L cells was significantly higher than hat of the wild type PSI cells(P＜0.05 ) and the caspase-3 protein expression level of the PS1M146L/APP751 CHO cells treated with 25 μmol/L ginsenoside-Rg1 was significantly lower than that of the untreated PS1M146L/APP751 CHO cells(P＜0.05). Conclusion Ginsenoside-Rg1 prevents cells from apoptosis through inhibiting the production of Aβ42 and decreasing the expression of the active caspase-3.