Cardioprotective activity of placental growth factor combined with oral supplementation of l-arginine in a rat model of acute myocardial infarction

Objective: Exogenous administration of placental growth factor (PlGF) stimulates angiogenesis and improves ventricular remodeling after acute myocardial infarction (AMI), and supplementation with l-arginine ameliorates endothelial function. The objective of the present study was to compare the cardioprotective effects of combination therapy of PlGF and l-arginine with those of direct administration of PlGF alone in a rat model of AMI.

Materials and methods: Fifty male Sprague Dawley rats were randomly divided into five groups: sham group, normal saline group, l-arginine group, PlGF group, and combination group (PlGF + l-arginine). An AMI rat model was established by ligation of the left anterior descending of coronary arteries. After 4 weeks of postligation treatment, cardiac function, scar area, angiogenesis and arteriogenesis, myocardial endothelial nitric oxide synthase (eNOS) and collagen I protein content, and plasma concentration of brain natriuretic peptide (BNP) were studied. Echocardiography, Masson's staining, immunohistochemical analyses, Western blot, and enzyme-linked immunosorbent assay were performed.

Results: Left ventricular ejection fraction (LVEF), left ventricular fraction shortening (LVFS), and capillary and arteriole densities were higher in the PlGF group than in the normal saline group (P<0.01). Scar area, collagen I protein content, and plasma concentration of BNP were decreased in the PlGF group (P<0.01). Myocardial eNOS protein level was elevated in the l-arginine group and PlGF + l-arginine group (P<0.01). Compared with the PlGF group, LVEF, LVFS, myocardial eNOS, and capillary and arteriole densities were higher in the combination group (P<0.01). Scar area, content of collagen I protein, and plasma concentration of BNP were reduced in the combination group (P<0.01).

Conclusion: Exogenous administration of PlGF stimulates angiogenesis and improves cardiac function. l-arginine increases the expression of the eNOS protein. PlGF and l-arginine have a more pronounced, synergistic protective effect on myocardial protection compared with that of exogenous PlGF therapy alone.