氧化型低密度脂蛋白诱导U937细胞凋亡时细胞间粘附分子-1的表达时序

研究氧化型低密度脂蛋白诱导人单核细胞U937细胞吞噬脂质发生凋亡过程中对细胞间粘附分子－1表达的影响，用胸腺嘧啶核苷将U937细胞阻滞在G1期，流式细胞仪监测同步化处理效果；流式细胞术检测U937细胞泡沫化过程中细胞凋亡和细胞间粘附分子－1的表达；逆转录－聚合酶链反应分析细胞间粘附分子－1 mRNA的表达，结果显示，80mg/L氧化型低密度脂蛋白温育U937细胞48h可形成典型的泡沫细胞，72h可见凋亡细胞增多；氧化型低密度脂蛋白温育U937细胞12h即可检测到细胞间粘附分子－1表达，24h时达到最高值，48h略有降低，72h时则明显降低。结果表明，氧化型低密度脂蛋白可以促进U937细胞细胞间粘附分子－1表达，细胞间粘附分子－1的表达增强有利于巨噬细胞的趋化运动和对脂质的吞噬。

Time Course of ICAM-1 Gene and Protein Expression in U937 Cell-Derived Foam Cells Induced by ox-LDL

Aim To explore the time course of expression of ICAM-1 gene and protein in macrophages foamy process induced by ox-LDL. Methods Cell cycle of Human myeloid leukemia U937 cells was arrested in G1 by preincubated with thymidine (2.0 mmol/L) for 24 h, then cells released at the same time. U937 cells were incubated with ox-LDL (80 mg/L) for time course(12 h, 24 h, 48 h or 72 h) treatment. Results Flow cytometric analysis results revealed that ICAM-1 protein expression increased from 12 h to 24 h and was highest at 24 h, but ICAM-1 decreased at 48 h. RT-PCR results showed that ICAM-1 mRNA level increased consistently with protein expression. Conclusions These results proved that ox-LDL could increase ICAM-1 gene and protein expression on U937 cells. Accumulation of cholesteryl esters in U937 cells has no negative feedback control on ICAM-1 gene and protein expression.