Fig. 1.

Experimental protocol. Five groups of mice were studied. The sham group underwent a thoracotomy and 1 h of open-chest state (without coronary occlusion) on day 1. The 1 h of open-chest state corresponded to the time interval necessary to perform 6 occlusion–reperfusion cycles in the late PC group; 24 h later (day 2), they underwent a 30-min coronary occlusion followed by 4 h of reperfusion. Mice in the late PC group were preconditioned with a sequence of 6 cycles of 4-min occlusion and 4-min reperfusion on day 1; on day 2, they were subjected to a 30-min coronary occlusion followed by 4 h of reperfusion. Mice in the age-matched control, LacZ, and HO-1 groups underwent the echocardiographic studies at 1 year (4 days prior to coronary occlusion) after gene transfer. The age-matched group did not receive any intervention during the period of the investigation. On day 1, mice in the LacZ and HO-1 groups were subjected to intramyocardial injections of rAAV/LacZ or rAAV/HO-1, respectively; at 1 year (4 days after echocardiographic measurements), both the LacZ and HO-1 groups underwent a 30-min coronary occlusion followed by 4 h of reperfusion for infarct size determination