DISTRIBUTION OF OVEREXPRESSED VASCULAR ENDOTHELIAL GROWTH FACTOR IN THE LEFT VENTRICLE FOLLOWING MYOCARDIAL INFARCTION

Abstract

Vascular endothelial growth factor (VEGF) mRNA is upregulated within a few hours after coronary artery ligation in pigs. However, it is unclear whether VEGF mRNA is overexpressed during the healing process following acute myocardial infarction (AMI). The aim of the present study was to investigate the relationship between serial changes in VEGF mRNA level in the left ventricle and angiogenic activity in the infarcted myocardium. Eighty male SD rats aged 8 weeks were used in this study. Left coronary artery ligation was performed in 40 rats, and a sham operation was performed in 40. The rats were sacrificed 3, 6, and 12 hours and 1, 2, 3, 7, and 14 days after the operation, and the hearts were collected. Northern blot was performed to assess the VEGF mRNA level in the left ventricle. Immunohistochemical staining for CD44 evaluated angiogenic activity in the infarcted area. VEGF mRNA levels on days 1 to 3 were greater in infarcted rats than in sham-operated rats. CD44-positive capillaries were detected from day 1 to 7 day in the infarcted area, and the number of CD44-positive capillaries was significantly greater on day 3 than at any other time points (p＜0.01). I suggest that serial changes in the VEGF mRNA level parallel the angiogenic activity of the infarcted area.