Figure 1.

Experimental protocols. A The control (CT) group (n=8) was challenged with 45 min (m) of hypoxia (striped bar) and 30 min of reoxygenation (open bar); the ischemic preconditioning (PR) group (n=8) received three cycles of 3 min of ischemia (closed bar) and 5 min of reperfusion (open bar) before hypoxia; the ischemic postconditioning (PT) group (n=8) received three cycles of 10 s of ischemia and 10 s of reperfusion before 30 min of reoxygenation; the PR plus PT (PR+PT) group (n=9) received three cycles of PR and three cycles of PT. B The CT group (n=8) was perfused with H₂O₂ (striped bar) until the left ventricular end-diastolic pressure was elevated to 50 mmHg (E) and then H₂O₂ was washed out for 30 min (open bar); the PR group (n=8) received three cycles of 3 min of ischemia and 5 min of reperfusion before perfusion with H₂O₂; the PT group (n=7) received three cycles of 30 s of ischemia and 30 s of reperfusion before a 30 min washout