雷公藤单体T10对Aβ1-42所致PC12细胞凋亡的抑制作用

阿尔茨海默病(Alzheimer's disease,AD)是发病率最高的中枢神经系统退变性疾病.目前AD的病因不清,亦无有效的防治手段,其重要的原因是尚无适宜的AD模型.因此,本实验首先建立了PC12细胞系β淀粉样蛋白(p-amyloid,Aβ)细胞损伤模型,在此基础上,探讨了中药免疫抑制剂雷公藤单体T10对细胞的保护作用及其机制.首先用不同浓度的Aβ(5×10、5×10-3、5×10-2、5×10、5、50 μmol/L)与PC12细胞共孵育48 h,用MTT法检测细胞存活率.选取Aβ致使细胞存活率降低的浓度(0.5、5、50 μmol/L)与PC12细胞共孵育48 h,通过流式细胞仪检测凋亡细胞百分比.用1×10-11mol/L的T10预孵育PC12细胞48 h后,加入50μmol/L Ap共孵育48 h,亦用流式细胞仪检测凋亡细胞百分比,激光共聚焦显微镜检测细胞内钙离子浓度变化.结果显示,Aβ的浓度存50μmol/L时可使细胞存活率降低至55.1%,凋亡细胞比例显著增加,而1×10-11mol/L的T10可明显降低50 μmol/L Aβ诱导的PC12细胞死亡.50 μmol/L Aβ可促进PC12细胞胞外钙离子内流,1×10-11mol/L的T10对Ap诱导的胞外钙离子内流有抑制作用.这些观察结果表明T10对Ap导致的PC12细胞损伤具有明显的保护作用,其机制可能与抑制Aβ诱导的胞内钙离子浓度升高和细胞凋亡有关.

Effect of Chinese herb Tripterygium wilfordii Hook F monomer triptolide on apoptosis of PC12 cells induced by Abeta1-42

Recent studies indicate that beta-amyloid (Abeta) is the key factor to cause neuronal degeneration in Alzheimer's disease (AD). In the present study, we set up an Abeta induced PC12 cell damage modle and studied the protective effect and related mechanisms of T(10), monomer extracted from Chinese herb Tripterygium wilfordii Hook F. PC12 cells were treated with different concentrations of Abeta (5x10(-4), 5x10(-3), 5x10(-2), 5x10(-1), 5, 50 micromol/L) for 48 h, cell viability was detected by MTT conversion. The apoptotic rate of PC12 cells was quantitatively determined using FACS assay. After PC12 cells were treated with 1x10(-11) mol/L T(10) for 48 h and then co-treated with 50 micromol/LAbetafor 48 h, the apoptotic rate and the change in intracellular Ca(2+) concentration of PC12 cells were analyzed by FACS assay and confocal, respectively. It was found that 5 micromol/L Abeta decreased the cell viability to 66.3% and 50 micromol/L Abeta decreased it to 55.1%, significantly different from that of the control group. After treatment with 50 micromol/L Abeta for 48 h, the apoptotic rate of PC12 cells increased obviously. The apoptotic rate was 5.37% in the control group, while after treatment with 0.5, 5 and 50 micromol/L Abeta for 48 h, the apoptotic rate of PC12 cells went up to 10.19%, 8.02% and 16.63%, respectively. At the same time, the concentration of intracellular Ca(2+) increased greatly after treatment with 50 micromol/L Abeta for 48 h. At the concentration of 1x10(-11) mol/L T(10) remarkably inhibited the apoptosis induced by 50 micromol/L Abeta. In the naive group, the apoptotic rate was 4.83%. The apoptotic rate went up to 17.24% after treatment with 50 micromol/L Abeta for 48 h. After co-treatment with 1x10(-11) mol/L T(10) and 50 micromol/L Abeta, the apoptotic rate decreased to 8.91%, significantly different from that of the control group. At the same time, at the concentration of 1x10(-11 )mol/L T(10) remarkably inhibited the increase of intracellular Ca(2+) concentration induced by Abeta. The results indicate that T(10) has obvious protective effect on PC12 cells, which may be related to the inhibition of the cell apoptosis and increment of intracellular Ca(2+) concentration induced by Abeta.