Objective To observe the effects of Zhilong Huoxue Tongyu Capsules on the levels of blood lipids and the expression of matrix metalloproteinase-2（MMP-2）and matrix metalloproteinase-9（MMP-9）in a rabbit model of carotid atherosclerosis

and to evaluate the protective effect of the drug against carotid atherosclerosis.Methods After adaptive feeding for 1 week

50 New Zealand white rabbits were randomly divided into five groups:normal control group

model group

Zhilong Huoxue Tongyu Capsule group

atorvastatin calcium tablet group

and Zhilong Huoxue Tongyu Capsule combined with atorvastatin calcium tablet group. A rabbit model of carotid atherosclerosis was established by using a high-fat diet combined with air desiccation of the carotid intima. One week after surgery

the Zhilong Huoxue Tongyu Capsule group was given the crude drug 3.12 g/kg/d

the atorvastatin calcium tablet group was given atorvastatin calcium 0.51 mg/kg/d

and the combination group was treated with the crude drug 3.12 g/kg/d plus atorvastatin calcium 0.51 mg/kg/d. After 4 weeks of drug intervention

blood samples were collected to measure the levels of blood lipids; the right carotid arteries were collected to prepare pathological sections and observe the pathological changes of each specimen

and Western blot was used to determine the activity of MMP-2 and MMP-9 in each carotid artery specimen. Results Compared with the normal control group

the model group showed significantly increased levels of all blood lipids and significantly increased expression of MMP-2 and MMP-9（all P < 0.05）. Compared with the model group

all drug treatment groups showed significantly decreased levels of blood lipids（P < 0.05）. Both single-drug groups had significantly reduced expression of MMP-2（P <0.05）; the Zhilong Huoxue Tongyu Capsule group exhibited significantly reduced expression of MMP-9（P < 0.05）

but there was no significant change in the atorvastatin calcium tablet group. The combination group showed significantly greater reductions in MMP-2 and MMP-9 levels than the single-drug groups（P < 0.05）. Conclusion Zhilong Huoxue Tongyu Capsules can reduce blood lipid levels

inhibit the expression of MMP-2 and MMP-9 in carotid atherosclerosis

and stabilize vulnerable plaques

showing a protective effect against carotid atherosclerosis.