The Time Patterns Of Circulating VEGF Expression Promoted By Myocardial Ischemia And Physiological Ischemic Training

Objective:To determine the time course of circulating serum VEGF promoted by myocardial ischemia and physiological ischemic training.Methods:Twenty three New Zealand rabbits were subjected to brief occlusion of left ventricle coronary artery branch(LVB).The ischemia model was the LVB occlusion by a balloon occluder for 2 minutes, repeated twice a day for 4 weeks.After myocardial models successfully completed,electrode from a pulse electrical stimulator was anchored in the sciatic nerve of hindlimb.The hindlimb underwent 5 minutes electrical stimulation(40Hz,2.5mA)followed by 5 minutes rest,repeated 8 times/d for 4 weeks.The subjects were randomly divided into sham operation group(SO),myocardial ischemia group(MI)and physiological ischemic training group(PI).Blood sample was collected at baseline and the 1w,2w,3w and 4w from each group.Serum VEGF concentrations were measured using ELISA kit.Results:1.VEGF was significantly increased in MI and PI,which reached peak at the end of 2^ndweek(P＜0.01).Both MI and PI have no significant difference in the 2^nd,3^rdand 4^thweek(P＞0.05)2.The circulating serum VEGF level was significantly increased in MI at any time point during experiment compare to SO(P＜0.01).Serum VEGF in PI was higher than that in MI after physiological ischemic training (P＜0.05).Conclusions:The peak VEGF expression occurred at the end of 2^nd week after 4-week training in PI.Physiological ischemic training may increase the expression of circulating serum VEGF over the effect of pure myocardial ischemia.