Temporal Phenomenon Of Myocardial Ischemia And Aerobic Exercise-induced VEGF Expression-an Experimental Study

Objectives: To study the temporal phenomenon of myocardial ischemia and aerobic exercise training induced expression of vascular endothelial growth factor (VEGF) in swine models of controllable myocardial ischemia.Methods: Twenty-four miniature swines were randomly assigned to control group (CG), ischemia group (IG) and exercise group (EG). A controllable hydraulic balloon catheter was placed to the first marginal branch of left circumflex coronary artery. Subjects in IG and EG received transient coronary occlusion for 2min repeated twice a day for 8 wks. Subjects in EG received 30 min aerobic exercise training on treadmill with intermittent high intensity duration of 2 min which repeated twice a session. Blood samples were obtained every 2 wks. The ischemic area of the myocardium was also sampled after the completion of the 8-week experiment. VEGF in serum were analyzed by ELISA and VEGF in myocardium was measured by Western Blot.Results: 1. VEGF serum level on wk 2 in IG was significantly higher than that in CG (p<0.05) and then reached plateau (P>0.05). 2. EG demonstrated the significant increase of VEGF from baseline to wk 4 (p<0.05), and then reached the plateau (P>0.05). 3. VEGF in serum was positively correlated that in myocardium (r=0.826, P<0.01).Conclusion: Intermittent myocardial ischemia and aerobic exercise training induced VEGF expression reaches peak on wk 2 and wk 4 respectively, and then reaches plateau. Dynamic observation of serum VEGF can be used for the longitudinal study of VEGF changes in vivo.