VEGF Expression Induced By Aerobic Training In Ischemic Myocardium Of Minipigs With Gradual Coronary Artery Occlusion

Objective: To investigate the effects of aerobic exercise training and the role of vascular endothelial growth factor (VEGF) on cardiac collateral development in minipigs subject to gradual coronary artery occlusion.Methods: Chronic coronary stenosis models were established by implantation of ameroid occluders on left circumflex coronary artery (LCX) in 18 pigs. Four weeks after surgery, The pigs were divided into sedentary group (n=4) and exercise group (n=8) which were further grouped to 4-week (Ex4, n=3), 6-week (Ex6, n=3) and 8-week (Ex8, n=2) respectively. Exercise protocol was 5.3 km/hour at 5?incline, 30 min/day and 5 days/week. 1) Collateral development was confirmed by pathological analysis. 2) cDNA fragments of VEGF gene were cloned and sequenced. VEGF mRNA expression was detected by RT-PCR. 3)VEGF protein expression was detected by Western blot.Results: 1) Capillaries in ischemic myocardium in the exercise group were significantly higher than the sedentary group (P < 0.01). 2) Two sequences of VEGF cDNA fragments were obtained, one of them was identified as a novel gene in the VEGF family and registered in GenBank. The mRNA expressions of VEGF gene in the group Ex4, Ex6 and Ex8 were significantly higher than the sedentary (P <0.01). 3) Theprotein expressions of VEGF gene in the group Ex4, Ex6 and Ex8 were significantly higher than the sedentary ones (P <0.01).Conclusions: Aerobic training induces significant myocardial VEGF mRNA and protein expression and may play a role in angiogenesis of ischemic myocardium in pigs with chronic coronary stenosis.