To investigate the dynamic changes of serum vascular endothelial growth factor（VEGF） levels in a rat model of acute myocardial infarction. Materials and methods.Eighty eight adult male Sprague Dawley rats weighing approximately 270 g were used in this study. Eighty rats were subjected to left coronary artery ligation

with 8 rats for each different duration of infarct. Eight sham operated animals in which the left coronary artery was surgically exposed without ligation were used as controls. Blood samples were drawn from the right atrium before （sham animals） and 1

3

6

12

24 h and 2

3

5

7

14 d after myocardial infarction. The concentrations of serum VEGF were measured by a sensitive enzyme linked immunosorbent assay with a rabbit polyclonal antibody specific for VEGF. Results. In the 8 control animals

the mean concentration of serum VEGF was 66.99±17.83 pg/ml. Six hours after myocardial infarction

the level of serum VEGF significantly increased to 125.68±28.07 pg/ml （P<0.01 vs. sham controls）

and reached a peak （240.61±70.63 pg/ml. P<0.01 vs. sham animals） at 24 h after ligation and then decreased gradually over the remaining 2 weeks. However

the level remained significantly elevated for 14 d （107.64±30.13pg/ml

P<0.01 vs. sham controls）. Conclusion. The present study shows that the levels of serum VEGF are markedly increased until 14 d in the rat model of acute myocardial infarction. The increased serum VEGF level may play an important role in the angiogenesis associated with myocardial infarction.