Effect Of Weekly Myocardial Ischemic Burden On Coronary Collateral Formation In Rabbit

Objective: To investigate the effect of weekly myocardial ischemic burden on coronary collateral formation in New Zealand rabbit.Methods: Intermittent myocardial ischemia model was established by installing a balloon occluder on the left ventricular branch (LVB) of coronary artery in 32 New Zealand rabbits. All subjects were assigned to two groups: sham-operated group and ischemic group, which was subdivided into 3, 5 and 7 days of ischemic stimulation. After 1 week of postoperative recovery, the LVB was repetitively occluded by inflating the balloon occluder for 2 min per hour, twice per day, 3, 5 and 7 days per week and lasted for 4 weeks. Meanwhile ECG was performed to observe myocardial ischemia. Ischemic myocardium was sampled to measure the capillary density through H.E. staining. Coronary collateral blood flow (CCBF) was measured with microsphere technique.Results: Compared with sham-operated group, CCBF and capillary density were significantly increased in ischemic groups. There were no significant differences in increment of CCBF and capillary density among 3 ischemic subgroups. There was no myocardial cell degeneration in all subjects.Conclusion: Ischemic burdens of myocardium with 3, 5 and 7...