Changes in the expression of vascular endothelial growth factor and basic fibroblast growth factor after acute myocardial infarction in rats

Objective By studying the expressions of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in rats′ cardiac muscle after acute myocardial infarction, we try to find out the relation between the expression of these two factors and the formation of new blood vessels under ischemia. Methods Wistar rats were divided into control group and infarction group (3, 7, 14, 28, 42, 56 d). The expression of VEGF and bFGF in cardiac muscle and endothelial cells is detected by means of immunohisto-chemial staining while the density of newly formed ressels is detected by marking the endothelial cells with antigens associated with factor Ⅷ. Results After ligating the left anterior descending coronary artery of the rats, the expression of VEGF and bFGF increased along with the prolongation of myocardial ischemia and reached the peak on the 7th day. The expression of the 2 factors began to decrease on the 28th day and the most significant decrease happened on the 42th and 56th day. The density of the newly formed capillaries is directly propontimal to the levels of the 2 factors. Less expression of VEGF and bFGF was observed in the control group. Conclusion The up-regulation of VEGF and bFGF expression might play important roles in neovascularization. Dicrectly intramyocardial injection of bFGF and VEGF gene at the time when the expression of bFGF and VEGF began to decrease maybe optimal.