摘要： Objective：This study was designed to investigate the protective effect of Dendrobium nobile Lindle. Alkaloids （DNLA） on the oxidative stress and apoptosis of PC12 cells induced by Aβ25-35，and further explore its potential mechanisms. Methods：PC12 cells were divided into 5 groups：control group，model group（10 μmol·L-1Aβ25-35），DNLA-L group（0.035 mg·L-1 DNLA+10 μmol·L-1 Aβ25-35），DNLA-M group （0.35 mg·L-1 DNLA+10 μmol·L-1 Aβ25-35）， DNLA-H group（ 3.5 mg·L-1 DNLA+10 μmol·L-1 Aβ25-35）. The cells were cultured in vitro and treated with Aβ25-35 for 24 h to induce PC12 after 6 hDNLA（ 0.035~3.5 mg·L-1） exposure. MTT assay was used to evaluate the effect of DNLA on cell viability induced by Aβ25-35，meanwhile Annexin V/PI staining by flow cytometry was used to detect apoptotic cells. Based on the identifi cation on that DNLA have antiapoptosis function towards that model，do research on effects of DNLA on oxidative stress induced byAβ25-35in PC12 cells by measuring intracellular ROS level，GSH level and SOD activity. Inverted immunofl uorescence microscopy was used to examine the effect of DNLA on mitochondrial membrane potential （MMP） stained with JC-1. Bax，Bcl-2，cleaved-caspase-9 and cleaved-caspase-3 expression level，key proteins of mitochondrial apoptotic pathway，were detected by Western blot，respectively. Results：Compared with control group，the cell viability was markedly decreased and the apoptosis showed notable increase in model group；exposure of cells to Aβ25-35 for 24 h elicited ROS production， while SOD activity，GSH expression level and MMP were markadly decreased，respectively；the protein expression of Bax，cleaved-caspase-9 and cleaved-caspase-3 were signifi cantly increased and the protein expression of Bcl-2 were decreased. However，compared with model，the cell viability of DNLA-M and DNLA-H was signifi cantly increased，and the apoptotic death was markedly decreased；ROS production was signifi cantly reduced，as well as SOD activation；on the other hand，pretreatment with DNLA at the concentration of 3.5 mg·L-1 dramatically enhanced both GSH content and MMP；the level of apoptosis relate protein Bax，cleaved-caspase-9 and cleaved-caspase-3 were significantly reduced；the protein expression of Bcl-2 was notably increased. Conclusions：Under the experimental conditions，DNLA have signifi cant inhabitation function on the apoptosis of PC12 cells induced by Aβ25-35，and its protential mechanism can be related to reducing the level of oxidative stress to inhibit mitochondrial apoptosisrelated protein expression.

关键词: Dendrobium nobile Lindle. Alkaloids, &, beta, -amyloid, oxidative stress, mitochondrial, apoptosis