胰岛素样生长因子Ⅰ抑制氧化型低密度脂蛋白诱导内皮细胞凋亡的体外试验

目的：胰岛素样生长因子Ⅰ作为重要的促细胞生长因子之一，其对内皮细胞凋亡影响的报道不多。实验拟验证和探讨胰岛素样生长因子Ⅰ对氧化型低密度脂蛋白诱导人脐静脉内皮细胞凋亡的抑制作用及可能机制。 方法：实验于2006—12／2007—07在华中科技大学同济医学院协和医院心血管疾病研究所完成。①实验材料及分组处理：取人新鲜脐带（产妇或家属签署知情同意书）分离培养人脐静脉内皮细胞，分为：胰岛素样生长因子Ⅰ组（1×10^-9mmol／L）、氧化型低密度脂蛋白（200mg／L）＋胰岛素样生长因子Ⅰ组（1×10^-9mmol／L）、氧化型低密度脂蛋白（200mg／L）组、正常对照组。分别在细胞培养24h后加入。②实验评估：采用四甲基偶氮唑盐法测定细胞活力；DAPI细胞核荧光染色法观察细胞凋亡的形态学变化及细胞凋亡率的测定；并进行内皮细胞caspase-3活性的检测。 结果：①氧化型低密度脂蛋白可明显抑制人脐静脉内皮细胞增殖，胰岛素样生长因子Ⅰ与氧化型低密度脂蛋白共同加入后，细胞增殖率明显上升（P〈0．05）。②氧化型低密度脂蛋白可诱导人脐静脉内皮细胞发生凋亡，而加入胰岛素样生长因子I刺激后细胞凋亡率降低（P〈0．05）。③caspase-3活性检测表明与对照组相比，氧化型低密度脂蛋白能明显上调caspase-3的表达，而胰岛素样生长因子Ⅰ＋氧化型低密度脂蛋白组caspase-3活性则降低（P〈0．05）。 结论：胰岛素样生长因子Ⅰ对氧化型低密度脂蛋白诱导的人脐静脉内皮细胞凋亡具有抑制作用，可能与其下调caspase-3蛋白表达有关。

Insulin-like growth factor Ⅰ inhibits oxidized lipoprotein-induced apoptosis of human umbilical vein endothelial cells in vitro

AIM： As a factor that can improve cell growth, there are few studies about the effect of insulin-like growth factor Ⅰ （IGF- Ⅰ ） on the apoptosis of endothelial cell. The study investigated the inhibition and mechanism of IGF- Ⅰ on the apoptosis of human umbilical vein endothelial cells （HUVEC） induced by oxidized low density lipoprotein （ox-LDL）.
METHODS： The experiment was performed in the Institute of Cardiovascular Disease, Union Hospital of Huazhong University of Science and Technology from December 2006 to July 2007. ①Fresh human umbilical cord was obtained （the informed consent） to isolate and culture HUVECs. The cells were divided into four groups. Except the control group, HUVEC cells were cultured with IGF-Ⅰ （1 × 10^-9mmol/L）, ox-LDL （200 mg/L）＋IGF- Ⅰ （1 × 10^-9mmol/L）, and ox-LDL （200 mg/L）, respectively after cultured for 24 hours. ②Cell viability was determined by MTT assay, morphology and apoptosis by DAPI fluorescence staining, and expressions of caspase-3 were analyzed.
RESULTS： ①Ox-LDL could significantly inhibit HUVEC cell proliferation. After treated with both IGF- Ⅰ and ox-LDL, the cell proliferation increased obviously compared with the cells treated with ox-LDL （P 〈 0.05）. ②Ox-LDL also induced HUVEC apoptosis, but the awoptosis rate was decreased by IGF-Ⅰ （P 〈 0.05）. ③caspase-3 viability test showed that compared with the normal control, ox-LDL markedly upregulated caspase-3 protein expressions of HUVEC, while IGF-Ⅰ＋ox-LDL treatment decreased caspase-3 protein expression significantly （P 〈 0.05）.
CONCLUSION： IGF-Ⅰ can inhibit the apoptosis of HUVEC induced by ox-LDL through its downregulating effect on the expression of caspase-3 proteins.