Effects of placental growth factor on revascularization after acute myocardial infarction in rats

Abstract

To investigate the effect of placental growth factor (PlGF) on revascularization after acute myocardial infarction. Myocardial infarction model was established by ligation of left anterior descending coronary artery in Wistar rats. Thirty AMI rats were divided into 3 groups with 10 in each group: PlGF, mouse VEGFR-1/Flt-1 antibody, or saline (control group) was injected in the infarcted border zone for each group, respectively. Two weeks later the hemodynamics parameters were measured with a left ventricular needle catheter and a biological signal analysis system; left ventricular remodeling was observed by HE staining; angiogenesis was examined by immunohistochemistry and cardiomyocyte apoptosis rate was detected by TUNEL. The stroke volume, systolic pressure and left ventricular developed pressure in PlGF group were all higher than those in control group (112±7 vs 65.63±8.50 μl, P<0.01; 131.61±9.26 vs 94.84±8.53 mm Hg, P<0.01 and 175.85±11.36 vs 105.50±15.83 mm Hg, P<0.01; respectively). PlGF animals had less ventricular dilation (left ventricular diameter 8.20±0.14 vs 9.25±0.32 mm, P<0.01) and increased left ventricular wall thickness (1.81±0.10 vs 1.35±0.10 mm, P<0.01) compared to controls. The geometry parameter of anti-VEGFR1 and control animals was almost the same. PlGF animals had increased angiogenesis compared to controls (29.44±5.75 vs 15.88±2.42 endothelial cells/high-powered field, P<0.01); the alpha smooth muscle actin (α-SMA) showed that PlGF animal had a higher density of artery than others (25.14±1.83 vs 19.70±2.52 arteries/mm(2), P<0.01), and the density of artery in anti-VEFGR1 group was less than the controls. The apoptosis rate of cardiomyocytes in PlGF animals was significantly lower than that in controls (9.51%±2.75% vs 37.81%±8.74%, P<0.01). Regional delivery of PlGF following acute myocardial infarction can improve cardiac function and left ventricular remodeling, enhance angiogenesis and reduce cardiomyocyte apoptosis rate. PlGF may be a potential agent in adjuvant therapy for acute myocardial infarction.