基于PI3K/Akt信号通路研究积雪草中微量皂苷(CA-1)的神经保护作用

Neuroprotective Effects of A Minor Saponin from Centella asiatica(CA-1)Based on PI3K/Akt Signaling Pathway

利用6-羟基多巴胺(6-Hydroxydopamine,6-OHDA)诱导分化型PC12细胞构建的帕金森病(Parkinson’s Disease,PD)体外细胞模型,研究了从积雪草中提取的微量皂苷(Centella Asiatica Saponins-1,CA-1)的神经保护作用。通过高分辨二级质谱鉴定化学结构、分析了积雪草中常用皂苷和CA-1对PC12细胞存活率的影响,进一步通过半定量和实时定量聚合酶链式反应、蛋白印迹等技术检测PC12细胞中相关基因和蛋白表达。结果表明在该模型中100μmol/L CA-1、积雪草苷(Asiaticoside,AS)、羟基积雪草苷(Madecassoside,MA)分别将细胞存活率提高了28.63%、16.69%、17.54%,CA-1的神经保护作用强于AS和MA(p<0.05)。与模型组相比,CA-1剂量依赖性地提高了6-OHDA诱导PC12细胞的存活率且在CA-1浓度为25μmol/L与模型组有显著差异(p<0.05),降低了细胞内活性氧(Reactive Oxygen Species,ROS)的水平,上调了Sod1、Cat、Bcl2基因表达。蛋白印迹法(Western Blot,WB)显示,CA-1提高了p85、PDK1、Akt的蛋白表达水平。在该研究中明确了CA-1的神经保护作用揭示了其作用可能通过PI3K/Akt信号通路。

The neuroprotective effects of a minor saponin extracted from Centella asiatica(CA-1)was investigated using the 6-hydroxydopamine(6-OHDA)-induced differentiated PC12 cells as the in vitro Parkinson's disease(PD)cell model.The chemical structure was identified by high-resolution secondary mass spectrometry,and the effects of common saponins and CA-1 in Centella asiatica on the cell viability of PC12 cells were examined.Further,the expressions of related genes and proteins in PC12 cells were detected by techniques such as semi-quantitative or real-time quantitative polymerase chain reaction(PCR)and western blot.The results showed that in this model,100μmol/L CA-1,asiaticoside(AS)and madecassoside(MA)increased cell viability by 28.63%,16.69%and 17.54%,respectively.The neuroprotective effect of CA-1 was stronger than those of AS and MA(p<0.05).Compared with the model group,CA-1 increased the survival rate of 6-OHDA-treated PC12 cells in a dose-dependent manner(which differed significantly from the model group at a CA-1 concentration of 25μmol/L p<0.05),decreased the intracellular reactive oxygen species(ROS)level,and up-regulated the gene expressions of Sod1,Cat and Bcl2.Western blot showed that CA-1 increased the protein expression levels of P85,PDK1 and Akt.In this study,the neuroprotective effect of CA-1 was confirmed,revealing that this effect may be through the PI3K/Akt signaling pathway.