Abstract: Objective To observe the effects of ATP-binding cassette A1 (ABCA1) on intercellular cell adhesion molecule type 1 (ICAM-1), monocyte chemoattractant protein-1 (MCP-1) and interleukin-1β (IL-1β) in THP-1 macrophages stimulated with 8-Br-cAMP to identify a possible new mechanism that ABCA1 contributes to atherosclerogenesis (AS). Methods Monocytic THP-1 cells were cultured in the presence of 100 nmol/L phorbol myristate acetate (PMA) for 72 h to transform the cells into THP-1 macrophages. After the macrophages were stimulated with 8-Br-cAMP (final concentration 0.5 mmol/L) for 3, 6, 12 and 24 h respectively, the amounts of ABCA1, ICAM-1 and MCP-1 mRNA were examined by real-time fluorescent quantitative RT-PCR, and the protein amounts of ABCA1, ICAM-1, MCP-1 and IL-1β were determined by Western blotting and enzyme-linked immunosorbent assay (ELISA). Phosphorothioate antisense oligonucleotides of ABCA1 were add into the culture media at a final concentration of 100 nmol/L and the experiments were repeated. Results ABCA1, ICAM-1 and MCP-1 mRNA and protein and IL-1β protein were increased in the macrophages after stimulation with 8-Br-cAMP for 6 and 12 h. The mRNA expressions of ABCA1, ICAM-1 and MCP-1 were decreased significantly at 3 and 6 h (P<0.01), and the protein expressions of ABCA1, ICAM-1, MCP-1 and IL-1β declined significantly at 12 and 24 h (P<0.01) after transfection of the macrophages with antisense oligonucleotides of ABCA1. Conclusion ABCA1 can increase the expressions of the inflammatory cytokines in THP-1 macrophages stimulated by 8-Br-cAMP and plays a role in the pathogenesis of AS.