中文摘要：

观察黄芪多糖（APS）对人微血管内皮细胞（HMEC-1）的保护作用以及Akt通路其中发挥的角色，以期探索APS细胞保护作用机制。用MTT法考察APS对HMEC-1细胞活力的影响；用体外缺氧缺糖（oxygen-glucose deprivation，OGD）模型，在OGD条件下，用LDH法检测细胞死亡率；用Western blotting法，研究APS对Akt通路的调节作用；利用Akt抑制剂Wortmannin作为阻断剂，考察Akt通路在APS细胞保护作用中发挥的角色。结果表明APS对HMEC-1细胞活力无明显影响，对OGD诱导的内皮细胞死亡具有一定的保护作用，可以显著减少细胞死亡率，且其保护作用具有剂量依赖性。且APS能诱导Akt磷酸化，而Akt抑制剂Wortmannin可降低APS对OGD诱导的内皮细胞死亡的保护作用。这些结果提示，APS可能是通过诱导Akt磷酸化，保护细胞减少OGD诱导的细胞死亡。

英文摘要：

The present study investigated the cytoprotective effect of a polysaccharide from Radix Astragali （APS） and the possible mechanism involved with Akt signal pathway. The effect of APS on human microvascular endothelial cells （HMEC - 1） cell viability was tested by MTT. The cell protective effect of APS was measured by Oxygen Glucose Deprivation （OGD） induced ischemia and cell death was measured byLDH assay. Meanwhile, ＇the effect of APS on phosphorylation of Akt by Western blotting was investigated and the Akt inhibitor Wortmannin was used as a blocking agent to test the role of Akt in which signaling pathways play in the cytoprotective effect of APS. The results showed that APS has no significant effect on HMEC - 1 ceils viability and can remarkably prevent cells from death induced by OGD in a concentration- dependent way. Meanwhile, the results showed that APS could induce phosphorylation of Akt. This eytoprotective effect of APS could be abolished by the Akt inhibitor wortmannin. It can be concluded that APS probably protects cells from death induced by OGD through inducing phosphorylation of Akt.