黄芪多糖对2型糖尿病患者外周血内皮祖细胞PI3K/Akt/eNOS信号通路的影响

背景：前期研究证实黄芪通过P38MAPK通路促进内皮祖细胞增殖,其影响是否通过PI3K/Akt/eNOS途径实现？目的：观察黄芪多糖对2型糖尿病患者外周血内皮祖细胞蛋白激酶B、内皮型一氧化氮合酶表达的影响。方法：采用密度梯度离心法获取糖尿病患者外周血单个核细胞,培养7 d后鉴定内皮祖细胞。观察0,50,200,800,3 200,6 400 mg/L黄芪多糖分别干预6,12,24,48 h对内皮祖细胞影响的量效和时效关系;用黄芪多糖及黄芪多糖与PI3K抑制剂LY294002联合干预糖尿病患者内皮祖细胞,Western blot检测磷酸化Akt及磷酸化内皮型一氧化氮合酶的表达水平。以未进行任何处理健康人内皮祖细胞作为对照组。结果与结论：糖尿病患者内皮祖细胞的增殖能力较对照组明显下降(P  < 0.05)。黄芪多糖显著增加糖尿病患者内皮祖细胞的增殖能力,当黄芪多糖在200~800 mg/L质量浓度范围,干预6~24 h可呈时间及剂量依赖性增强内皮祖细胞的增殖能力(P < 0.01),并呈剂量依赖性升高内皮祖细胞磷酸化Akt及磷酸化内皮型一氧化氮合酶的表达(P < 0.05);PI3K抑制剂LY294002能阻断黄芪多糖诱导的Akt、内皮型一氧化氮合酶的磷酸化(P < 0.05)。说明黄芪多糖通过激活PI3K/Akt/eNOS信号通路促进内皮祖细胞增殖和向内皮细胞的分化。

Effect of astragalus polysaccharides on peripheral endothelial progenitor cells via PI3K/Akt/eNOS signal pathway in patients with type 2 diabetes

BACKGROUND:Previous studies have demonstrated that Astragalus can promote the proliferation of endothelial progenitor cells (EPCs) via P38MAPK pathway. Whether PI3K/Akt/eNOS signal pathway can replace P38MAPK pathway needs further studies.OBJECTIVE:To observe the effect of astragalus polysaccharides (APS) on the expression of protein kinase B (PKB) and endothelial nitric oxide synthase (eNOS) of EPCs from peripheral blood in patients with type 2 diabetes.METHODS:Mononuclear cells from diabetic patients were isolated by Ficoll density gradient centrifugation, and identified as EPCs after 7 days. Dose-depended and time-depended effects of APS with six different concentrations (0, 50, 200, 800, 3 200, 6 400 mg/L) and different treatment time (6, 12, 24, 48 hours) on EPCs proliferation and differentiation were measured. EPCs were treated with APS alone or APS combined with LY294002 to observe the expressions phosphorylated Akt and eNOS using Western Blot. EPCs from healthy persons were used as controls.RESULTS AND CONCLUSION:The proliferative ability of EPCs in the diabetic group was significantly lower than that in the control group (P < 0.05). 200-800 mg/L APS within 6-24 hours could promote the proliferative ability of EPCs in a time- and dose-depended manner (P< 0.01). With dose increasing, the expressions of phosphorylated Akt and eNOS were also increased (P < 0.05). LY294002 could inhibit the phosphorylation of Akt and eNOS (P < 0.05). The findings indicate that APS can promote the proliferation and differentiation of EPCs into endothelial cells via activated PI3K/Akt/eNOS pathway.