| Objective: To develop a controlled myocardial ischemic model of rabbit, and explore the effect of daily ischemic burden on expression of Vascular Endothelial Growth Factor (VEGF) in myocardium of New Zealand rabbit.Methods: According to daily ischemic frequency, 38 adult New Zealand rabbits (2.0~2.5kg) were assigned to five groups: control group, sham-operate group, the study group was designed as 2,4 and 6 time group according to the daily frequency of ischemic stimulation. Intermittent myocardial ischemia model was performed by a balloon occluder on the left ventricle coronary artery. Seven to ten days after surgery, 2-min coronary occlusions per hour by inflating balloon occluder were performed daily and lasted for 4 weeks, meanwhile ECG was observed. Ischemic myocardium was sampled for histological examination. Expression of VEGF in ischemic myocardium was analyzed by Western Blot. Blood serum was obtained on baseline, pre and 24 hrs post ischemic stimulation for detecting cardiac troponin I (cTnI). Results: The inflation of balloon occluder induced elevation of S-T segment immediately, indicating onset of myocardial ischemia. Compared with the control group and sham-operate group, the expression of VEGFwas obviously increased in the in ischemic groups (p<0.05). There was no myocardial cell degeneration and thrombus found in all subjects, and no significantly increasing in blood cTnI 24 hours post ischemic stimulation. Conclusion: Pneumatic occluder is applicable to make a animal model of controlled myocardial ischemia in rabbit. Four week intermittent myocardial ischemia may increase the expression of VEGF in myocardium without irreversible myocardial damage. Increase of daily ischemic frequency does not enhance VEGF expression.
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