AimTo study the influence of angiotensinⅡ（AngⅡ） and angiotensin(1-7)(Ang(1-7))on expression of ATP-binding cassette transporter A1（ABCA1）and cholesterol efflux in THP-1 macrophages.MethodsTHP-1 monocytes were stimulated and differentiated into macrophages.They were divided into blank control, AngⅡ group, Ang(1-7) group, concentration of Ang(1-7) + AngⅡ group, and Ang(1-7) + AngⅡ+A-779 group.The expression of ABCA1 mRNA and protein were measured by RT-PCR and Western blot, cholesterol effluent was measured by liquid scintillator.ResultsCompared with the control group, AngⅡ decreased ABCA1 in both protein (0.473±0.029 vs 0.652±0.031,p<0.05) and mRNA(0.471±0.036 vs 0.857±0.053,p<0.05) and inhibited the cholesterol efflux(8.937±0.353 vs 13.942±0.478,p<0.05).However, Ang(1-7) opposed the reduction of ABCA1(0.722±0.045 vs 0.652±0.031,p<0.05) and ABCA1 mRNA(0.949±0.087 vs 0.857±0.053,p<0.05） induced by AngⅡ, and promoted the cholesterol efflux(15.477±0.882 vs 13.942±0.478,p<0.05), which appeared dose-dependent.When incubated with A-799, an inhibitor of Ang(1-7), the effects of Ang(1-7) on promoting the expression of ABCA1, ABCA1 mRNA and the cholesterol efflux were significantly attenuated(0.515±0.048 vs 0.473±0.029,0.472±0.063 vs 0.471 ±0.036,9.309±0.333 vs 8.937±0.353,p>0.05).ConclusionThe effects of AngⅡ on the atherosclerosis may be correlated to the down-regulation of ABCA1.Ang（1-7）concentration-dependently attenuated the reduction of ABCA1 induced by AngⅡ in THP-1 derived macrophages through its specfic receptor Mas,and increased the cholesterol effluent.