Objective To explore the effect of oxLDL on CXC chemokine growthregulated oncogene α (GROα) expression in human endothelial cells and the possible functional signific ance of the effect Methods LDL was isolated by sequential ultracentrifugation and oxidized to oxLDL Rever se transcriptionpolymerase chain reaction with GAPDH as internal standard was applied and CXC chemokine GROα mRNA in endothelial ECV304 cells was examined ELISA was used to determine GROα protein expression on ECV304 cell surface and in the medium With static cell adhesion assays, the physiological significa nce of elevated GROα expression was tested Results OxLDL, not LDL, treatment of ECV304 cells significantly induced the expression o f GROα mRNA that was not detectable in untreated cells Induction of expressio n was first evident at 1h, became maximal at 2h, and was substantially decre ased by 4h In a concentration and timedependent manner, oxLDL, and not L DL, induced a significant upregulation of GROα surface expression in ECV304 cel ls that was at a barely detectable level in unstimulated ECV304 cells GROα protein in the medium did not change significantly Exposure of ECV304 cells to 40μg protein /ml oxLDL for 24h resulted in a marked increase in the number of U937 cells bound to ECV304 cells and antibodies to GROα inhibited adhesion Conclusion OxLDL functionally upregulated GROα expression in endothelial cells