Abstract: Objective To study the inhibitory effects of N-aetyl-cysteine(NAC) on the expressions of matrix metalloproteinases (MMPs) of macrophage-derived foam cells (FCs). Methods The hypercholesterolemic (0.5% cholesterol and 4.5% coconut) rabbit model of atherosclerosis was used to investigate the gelatinolytic activity associated with FCs，which were isolated from rabbit atheroma. FCs were maintained in culture medium for 24 h up to 4 d, NAC (10 mmol•L^-1) was added to culture medium of FCs.The expresions of MMPs were detected with SDS PAGE and immunohistochemistry assay.Results The Pro-MMP9 concentrations in NAC group at 24 h,48 h and 4 d［(654±33.5)，(780±65.0) and (799±48.9)INT•mm^-2］were lower than those in control group［(1455±50.9),(15 615±52.0) and (1 467±48.8)INT•mm^-2］ (P<0.01).At 24 h,48 h and 4 d the concentrations of MMP2 in NAC group ［(221±25.3),(224±25.0) and (202±33.9) INT•mm^-2］were lower than those in control group［467±34.3),(651±42.0) and (671±34.8)INT•mm^-2］(P<0.01),the immunohistochemical result showed MMP2(+ ), macrophage(+), and MMP9(+).Conclusion This newly described action of antioxidant therapy might be useful to inhibit matrix degradation and to improve vascular stability. NAC represents an attractive therapeutic target.

Key words: matrix metalloproteinases, arteriosclerosis