ObjectiveTo compare the effects on left ventricular remodeling of bone marrow mononuclear cells transplantation one week and three months after acute myocardial infarction.MethodsAcute myocardial infarction models were successfully established in 15 swine,which were randomly divided into three groups:placebo group,early transplantation group and late trasplantation group.One week after model had been established,early transplantation group underwent bone marrow mononuclear cells transplantation,and then so did the late trasplantation group three months after acute myocardial infarction.B-ultrasound and single photon emission computed tomography (SPECT) examinations were performed to assess the left ventricular end diastolic dimension( LVd),left ventricular end diastolic volume(EDV) and left ventricular ejection fraction(EF) before and one week,three months,six months after acute myocardial infarction.ResultsThe LVd of late transplantation group [ (54.20:t:3.70) mm] was lower than placebo group [ (63.20 ±5.63)mm],but higher than early transplantation group [ (47.40 ± 1.14)mm].The EDV of late transplantation group [ ( 163.00 ±6.96)ml] was lower than placebo group [ (209.40 ± 18.69)ml],but higher than early transplantation group [ ( 135.40 ± 4.93 ) ml ].The EF of late transplantation group (0.25 ±0.02) was higher than placebo group (0.19 ±0.02),but lower than early transplantation group (0.37 ±0.02).ConclusionsBone marrow mononuclear cells transplantation can alleviate progressing ventricular remodeling,even it is performed three month after acute myocardial infarction,but its therapeutic effects are inferior to early transplantation's.