Abstract: Objective To study the relationship between matrix metalloproteinase-9 and carotid atherosclerosis plaque’s stability. Methods The bilateral carotid atherosclerosis of 48 asymptomatic carotid atherosclerosis patients(ACA group) and 20 normal controls(NC group) were examined with color Doppler. The serum levels of MMP-9 in all the groups were measured by enzyme linked immunosorbent assay. Results Carotid atherosclerosis plaque was not found in NC group. The serum levels of MMP-9 in ACA group were significantly higher than that in NC group(all P<0.05). In ACA group, the serum levels of MMP-9 in vulnerable plaque subgroup were significantly higher than that in stabled plaque subgroup(all P<0.05) and the serum levels of MMP-9 in stable plaque subgroup were signiifcantly higher than that in no plaque subgroup(all P<0.05). Conclusion The serum levels of MMP-9 can be serum markers of carotid atherosclerosis plaque and its stability index.

Key words: matrix metalloproteinase-9, carotid atherosclerosis, plaque stability