Objective To observe the intervening effect and acting mechanism of Simiaoyongan Decoction (SYD) on extracellular matrix in rabbit's Atherosclerosis plaque.

Methods 40 Japanese white rabbits were randomly assigned to four groups: the normal control group, model group, SYD group and simvastatin group in which there were 10 animals. Levels of Collagen, α-SMA, MMP-9 and NF-κB expression in aortic wall were measured at the terminal of experiment.

Results Compared with the model group, MMP-9 and NF-κB expression in aortic wall were lower in the treated groups after treatment; Collagen and α-SMA level increased (p<0.01or p<0.05).

Conclusion SYD could suppress degradation of extracellular matrix to stabilise atherosclerosis vulnerable plaque. Its mechanism can be the restraint in MMP-9 and a cell signalling protein NF-κB expressions