Effect Of Daily Myocardial Ischemic Burden On Coronary Collateral Blood Flow Of Rabbit

Objective: To explore the effect of daily myocardial ischemic burden on coronary collateral blood flow (CCBF) of New Zealand rabbit. Methods: Intermittent myocardial ischemia model was established by installing a balloon occluder on the left ventricle coronary artery (LVA) in 34 New Zealand rabbits. All subjects were assigned to two groups: sham-operate group and ischemic group, which was subdivided into 2, 4 and 6 times subgroup according to daily frequency of ischemic stimulation. Seven days after surgery, 2-min coronary occlusions per hour with different daily ischemic burdens using inflating balloon occluder were performed daily and lasted for 4 weeks, meanwhile ST segment elevation of ECG was adopted as criteria of myocardial ischemia. Ischemic myocardium was sampled for histological examination. CCBF was measured with microsphere technique. Blood serum was obtained on baseline, pre and 24h post the first ischemic stimulation for detecting cardiac troponin I (cTn-I).Results: Compared with sham-operate group, CCBF was obviously increased in ischemic group (P<0.05). There was no significant difference in increase of CCBF among 3 ischemic subgroups (P>0.05). There was no myocardial cell degeneration in all subjects, and no significant increase of...