Expression of intercellular adhesion molecule-1 in U937 foam cells and inhibitory effect of imperatorin.
AIM
To investigate the expression level of intercellular adhesion molecule-1 (ICAM-1) in a macrophage-derived foam cell model from human U937 cell line and the inhibitory effect of imperatorin (IMP) on the ICAM-1.


METHODS
U937 cells were incubated with oxidized low density lipoprotein (ox-LDL) 80 mg/L for 48 h and a macrophage-derived foam cell model was established. The medium was pretreated with different concentrations of IMP (0, 25, 50, 100 micromol/L). ICAM-1 protein expression in cells was measured with Western blotting; ICAM-1 mRNA level in cells was measured by Northern blotting.


RESULTS
After incubated with ox-LDL, ICAM-1 expression level increased greatly. The increase in ICAM-1 protein level and mRNA level was estimated to be about 15-fold and 10-fold. When the cells were pretreated with imperatorin (50, 100 micromol/L), the increase of ICAM-1 in foam cells were remarkably inhibited. Especially when pretreated with IMP 100 micromol/L, the ICAM-1 protein level decreased by 79 % and the mRNA level decreased by 74 % each compared to the level of foam cells.


CONCLUSION
After incubated with ox-LDL in vitro, the U937 foam cells showed an enhanced ICAM-1 expression compared with normal U937 cells. IMP could inhibit the expression of ICAM-1 in U937 foam cells.