Aim To observe the effect of amlodepine on pregnancy-associated plasma protein-A in atherosclerosis. Methods 20 male New Zealand rabbits were fed on a diet of 1%cholesterol for 12 weeks after they underwent ballon-induced abdominal arotic wall injury.At the end of the 12th week,they were divided into 2 groups at random. One group was given Amlodipine(5 mg/d) for 12 weeks,the other was control group.At the beginning of the experiment, the end of 12th week and 24th week,blood samples were collected to measure the concentrations of pregnancy-associated plasma protein-A and high sensitive C-reaction protein;at the same time,abdominal aorta were examined by high frequency ultrasound.At the end of 24th week,abdominal aorta were processed and examined by pathological stain and immunohistochemical stain for pregnancy-associated plasma protein-A.Results Pathological results and electron microscope showed that compared with control group,the plaque area and Lipid deposition of amlodipine group reduced, smooth muscle cells increased and collagen minished.Ultrasound measurements also showed that intima-media thickness and end systolic diameter were significantly decreased(P<0.01) and corrected intima-media echo intensity was increased (P<0.01) in amlodipine group.Amlodipine also decreased pregnancy-associated plasma protein-A and high sensitive Creaction protein in blood(P<0.01) and pregnancy-associated plasma protein-A expression in atherosclerotic plaque with immunohistochemical stain.Pregnancy-associated plasma protein-A had a close relationship with high sensitive C-reaction protein and intima-media thickness(R~2 = 0.424 and R~2 = 0.339).Conclusion Pregnancy-associated plasma protein -A is associated with severity of atherosclerosis.Amlodipine can regress atherosclerosis by inhibiting pregnancy-associated plasma protein-A.