Objective: To study the preventive mechanism of modified Buyang Huanwu Tang on formation of atherosclerosis. Method: Thirty male ApoE-/- mice were randomly divided into four groups:ApoE-/- mice blank group

model group

modified Buyang Huanwu Tang group and simvastatin group. Normal male C57BL/6J mice were used as a normal group. High-fat diet was given for modeling in model group

modified Buyang Huanwu Tang group and simvastatin group. 4 weeks later

the mice in Buyang Huanwu Tang group or simvastatin group were intragastrically administrated with Buyang Huanwu Tang (20 g·kg-1)+leech powder (0.46 g·kg-1) or simvastatin(3 mg·kg-1). After 9 weeks

the total cholesterol (TC)

triglyceride (TG)

high density lipoprotein cholesterol (HDL-C) and low density lipoprotein cholesterol (LDL-C) in serum were detected. In addition

aorta segment was taken from the experiment animals to observe morphological changes by HE staining

measure fiber-cap thickness and vascular intima-media thickness. Western blot was used to determine the expression levels of aortic p38 mitogen activated protein kinase(p38MAPK) and extracellular signal-regulated kinase 5(ERK5). Result: As compared with the normal group

TC

TG and LDL-C levels were significantly increased in the ApoE-/-mice blank group and model group

while HDL-C level was significantly decreased (P<0.01). As compared with the model group

TC

TG and LDL-C levels were decreased in the modified Buyang Huanwu Tang group and simvastatin group

while HDL-C level was significantly increased (P<0.05

P<0.01). HE staining showed no aortic plaque formation in C57BL/6J mice normal group

few aortic plaque formation and slightly increased vascular intima-media thickness in ApoE-/- mice blank group

significant aortic plaque formation and increased vascular intima-media thickness in model group. As compared with the model group

aortic plaque formation and vascular intima-media thickness was reduced in both modified Buyang Huanwu Tang group and simvastatin group. The protein expression level of aortic p38MAPK in model group was higher while protein expression level of ERK5 was lower than those in C57BL/6J normal group (P<0.01). In addition

the protein expression level of aortic p38MAPK was significantly decreased while the protein expression level of ERK5 was increased in both modified Buyang Huanwu Tang group and simvastatin group as compared with model group (P<0.01

P<0.01). Conclusion: Both modified Buyang Huanwu Tang and simvastatin have an effect in preventing the development of atherosclerosis

and the potential mechanism could be related to intervening p38MAPK and ERK5 in MAPK signal pathway.