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

摘要:

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100 μmol/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25 μmol/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。

Abstract:

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, 100 μmol/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 25 μmol/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.