Aim To explore the changes of peroxisome proliferator-activated receptor-γ(PPAR-γ),nuclear factor-κB(NF-κB),metalloproteinase-9(MMP-9) and metalloproteinase inhibitor-1(TIMP-1) expressed by peripheral blood monocyte-derived macrophages(MDM) in patients with acute coronary syndrome(ACS) and the relations among them.Methods 48 patients with ACS and 28 cases with stable angina pectoris(SAP) were admitted.A 20 mL fasting blood sample was obtained using a blood cell-separator tube.Peripheral blood mononuclear cells were isolated,and macrophage colony-stimulating factor was added to train them for MDM.After CD40 ligand stimulating,the concentrations of MMP-9 and TIMP-1 in the supernate of MDM and the expression strength of PPAR-γ,MMP-9,TIMP-1 mRNA and NF-κB subunit P65(NF-κB P65) by MDM were determined.Results In ACS group,the expression strength of PPAR-γ mRNA was lower than the SAP group(0.24±0.04 vs 0.39±0.06;P<0.001),while the expression strength of NF-κB P65 was higher than the SAP group(0.42±0.06 vs 0.27±0.02;P<0.001),both the concentration of MMP-9 and TIMP-1 in the supernate of MDM were significantly higher than the SAP group(231.11±51.47 μg/L vs 126.06±13.2 μg/L,P<0.001;139.80±31.54 μg/L vs 112.250 vs 12.68 μg/L,P<0.05),the expression strength of mRNA of MMP-9 and TIMP-1 were higher than the SA group(0.67±0.11 vs 0.24±0.05,P<0.001;0.42±0.09 vs 0.33±0.06,P<0.05).The expression strength of PPAR-γmRNA were negatively correlated to NF-κB P65 and the expression strength of MMP-9(P<0.001),but not correlated to the expression strength of TIMP-1(P>0.05);the expression strength of NF-κB P65 were positively correlated to the expression strength of MMP-9 and TIMP-1(P<0.001).Conclusion For MDM of patients with ACS,the expression strength of PPAR-γ was down-regulated,while the expression strength of NF-κB and MMP-9 was up-regulated.The PPAR-γ may regulate MMP-9 expression before transcribed by regulating the activity of NF-κB.TIMP-1 expression may not be regulated by PPAR-γ.