Proteomic analysis of left ventricular tissues following intermittent myocardial ischemia during coronary collateralization in rabbits

Background: Repeated transient myocardial ischemia may offer favorable effects to coronary perfusion via collateral circulation, although the underlying molecular mechanisms still remain unclear. This study was designed to evaluate the proteomic changes during this process. Methods: Rabbits were randomly divided into sham-operated and ischemic groups ( 5 each) and were subjected to intermittent myocardial ischemia by inflation or deflation of pneumatic occluders for 4 weeks to establish a controlled myocardial ischemic model. Isolated hearts were subjected to histological observation, microspheric detection, capillary counting and proteomic analysis. Results: Elevation of ST segment or back to normal in Lead-II electrocardiogram could be induced by occluders without overt histological and cardiac troponin I alterations. Regional coronary collateral blood flow exhibited a remarkable increase following intermittent inflation of occluders in the ischemic group ( P<0.01). Simultaneously, capillary numbers per unit area were significantly different between groups ( P<0.01). Twenty-three differentially expressed protein spots were separated by two-dimensional gel electrophoresis and 13 out of them were identified by MALDI-TOF-MS. Conclusion: The present study indicates that the differentially expressed proteins involved in proliferation, growth and energy metabolism following intermittent myocardial ischemia without ischemia-reperfusion injury are likely associated with the development of collateralization beneficial to coronary circulation. (C) 2007 Elsevier Ireland Ltd. All rights reserved.