人外周血内皮祖细胞增殖、凋亡及丙二醛、抗氧化因子合成与波动性高糖的影响

背景：研究表明波动性高血糖较持续性高血糖对血管内皮功能的损害可能更严重。 目的：观察波动性高糖对人外周血内皮祖细胞增殖、凋亡及丙二醛、抗氧化因子合成的影响。 方法：密度梯度离心法获取人外周血单个核细胞。取经培养鉴定后的内皮祖细胞，细胞同化后分别给予5.5 mmol/L，20 mmol/L，5.5/20 mmol/L葡萄糖(5.5，20 mmol/L的葡萄糖培养液每8 h更换1次)及20 mmol/L甘露醇。干预72 h后，MTT法检测内皮祖细胞的增殖情况；流式细胞仪检测细胞凋亡率；比色法测定培养液中丙二醛水平及超氧化物歧化酶活力。 结果与结论：20 mmol/L和5.5/20 mmol/L葡萄糖作用72 h，内皮祖细胞增殖减少、凋亡率增高(P < 0.01），培养液中丙二醛水平增高、超氧化物歧化酶活力降低(P < 0.01)，均以5.5/20 mmol/L葡萄糖作用最明显(P  < 0.01)。说明波动性高糖较恒定性高糖更易抑制内皮祖细胞增殖并促进其凋亡，其机制可能与波动性高糖环境下氧化应激水平增高有关。

Effect of intermittent high glucose on proliferation and apoptosis of endothelial progenitor cells from human peripheral blood as well as the production of malondialdehyde and antioxidant

BACKGROUND:Studies have demonstrated that intermittent high glucose can have a more severe impact on vascular endothelial function in comparison with persistent hyperglycemia. OBJECTIVE:To investigate the effect of intermittent high glucose on the proliferation and apoptosis of endothelial progenitor cells (EPCs) from human peripheral blood in vitro as well as the production of malondialdehyde (MDA) and antioxidant. METHODS:Total mononuclear cells were isolated from human peripheral blood by Ficoll density gradient centrifugation and then the cells were placed on fibronectin-coated culture dishes. After 7 days of culture, the adherent cells were identified as EPCs by laser scanning confocal microscope. The cells were synchronized and then stimulated with glucose 5.5 mmol/L (normal control group), 20 mmol/L (constant high glucose group), and 5.5/20 mmol/L (intermittent high glucose group, 5.5 and 20 mmol/L glucose culture solution was changed every 8 hours) for 72 hours. EPCs proliferation and apoptosis was measured by MTT assay and flow cytometry, respectively. The content of MDA and the activity of superoxide dismutase (SOD) in culture solution were detected with colorimetry. RESULTS AND CONCLUSION: AfterEPCs were exposed to constant high glucose (20 mmol/L) and intermittent high glucose (5.5/20 mmol/L) for 72 hours, proliferated cells were significantly reduced and the apoptosis rate was significantly increased compared with those exposed to normal glucose (P < 0.01). Furthermore, there was a significant increase in MDA contents as well as a significant reduce in SOD activities in the constant high glucose and intermittent high glucose group (P < 0.01), especially in the latter group. These findings indicated that both intermittent high glucose and constant glucose could inhibit the proliferation and promote the apoptosis of EPCs; however, intermittent high glucose appears to worsen the effects on EPCs. This is maybe due to the increased oxidative stress.