促红细胞生成素预防人脐静脉内皮细胞凋亡的作用

Mechanism of inhibition of apoptosis of human umbilical vein endothelial cells induced by oxidized-low density lipoprotein by erythropoietin

目的建立氧化低密度脂蛋白（ox—LDL）诱导培养人脐静脉内皮细胞（HUVECs）凋亡模型，探讨促红细胞生成素（EPO）对ox—LDL诱导HUVECs凋亡的影响。方法取体外培养3～6代的HUVECs用于实验。实验分为两组：一组细胞予以不同浓度（6．25、50、100kU／L）重组人促红细胞生成素（rhEPO）预处理24h，再加入100mg／LOX—LDL孵育48h；另一组细胞加入反式或顺式LOX-1 mRNA预处理24h，再加入100mg／L的ox—LDL孵育12h。采用存活率、凋亡率和Bcl-2／Bax比值评价细胞凋亡情况。结果与ox—LDL组比较，随rhEPO浓度的递增，细胞存活率增高，细胞凋亡率降低，凋亡蛋白Bcl-2／Bax比值增高（P均〈0．05），呈剂量依赖性。反式LOX-1 mRNA（0．5μmol／L）预处理组凋亡蛋白Bcl-2／Bax比值较OX—LDL组明显增高（P〈0．05）；顺式LOX-1 mRNA（0．5μmol／L）预处理组Bcl-2／Bax比值与ox—LDL组则无明显差异。结论ox—LDL可以诱导HUVECs凋亡，并且通过LOX-1 mRNA来调节，rhEPO可增高Bcl-2／Bax比值，抑制ox—LDL诱导的HUVECs凋亡。

Objective To explore the protective effect of erythropoietin （EPO） against oxidized-low density lipoprotein （ox-LDL）-induced apoptosis in human umbilical vein endothelial ceils （HUVECs） in an ox-LDL induced apoptosis model. Methods Third - sixth passage of cultured HUVECs were used, and they were divided into two groups. The cells were pretreated with different concentrations （6.25, 50, 100 kU/L） of recombinant human erythropoietin （rhEPO） for 24 hours, then they were exposed to ox-LDL （100 mg/L） for 48 hours; another group of cells were pretreated with antisense to 0.5 μmol/L LOX-1 mRNA or 0. 5 μmol/L sense for 24 hours, and then HUVECs were exposed to ox-LDL （100 mg/L） for 12 hours. Apoptosis was assessed by the apoptosis ratio, cell viability, and Bcl-2/Bax ratio. Results As compared to untreated controls, pretreatment with rhEPO led to increased cell survival of HUVECs and decreased cell apoptosis in a dose-dependent manner （all P〈0.05）. Consistently, the Bcl-2/Bax ratios were also increased in a similar fashion. The ratio of apoptosis protein Bcl-2/Bax was increased in the antisense LOX-1 mRNA group than that of ox-LDL group （P〈0.05）, but the one in the sense LOX-1 mRNA group was not significantly different from that of ox-LDL group. Conclusion The ox-LDL can induce apoptosis in HUVECs by regulating LOX-1 mRNA, and rhEPO can increase Bcl-2/Bax ratio and inhibite ox-LDL-induced apoptosis of HUVECs.