Objective To investigate the effects of Lp(a)on proliferation GMCs of rat model induced by lipopolysaccharide and explore the possible mechanism of Lp(a)in the proliferation of rat GMCs.Methods To observe the effects of Lp(a)on proliferation of GMCs,different dosage of Lp(a)were used,The research were divided into three groups:Control group,LPS group,Lp(a)group.After culture(at the end of 12h,24h,48h,60h and 72h),the cultured GMCs and suspension were collected to observe the rate of GMCs proliferation by MTT,the positive rate of proliferation cell nuclear antigen(PCNA)by immunohistochemisty,and the level of intercellular adhesion molecule-1(ICAM-1)by ELISA respectively.Results Compared with control and LPS group,MTT,positive rate of PCNA and ICAM-1 of GMCs were increased more significantly in Lp(a)group.MTT ,the positive rate of PCNA and ICAM-1 of GMCs were increased as Lp(a)dosage increased,a maximal effect was seen when Lp(a)was 2.5 μg/L or 5.0μg/L.When the dosage continue increased,MTT,the positive rate of PCNA and ICAM-1 activity of GMCs began to decrease in Lp(a)group.ICAM-1 showed positive correlation with MTT and the positive rate of PCNA.Conclusion Lp(a)can significantly affect the rate of GMCs proliferation,and this affection is in a dosage-and timedependent manner.Low dosage stimulates GMCs proliferation, and high dosage inhibits GMCs proliferation.ICAM-1 shows positive correlation with MTT and the positive rate of PCNA.The effect of Lp(a)on GMCs may be through ICAM-1.