OBJECTIVETo explore the delayed protection of exercise preconditioning from the relative myocardial ischemia-reperfusion injury.

METHODSThe experiment included the vivo experiment and the vitro experiment, 32 Wistar rats in each experiment were divided into 4 groups randomly: control group (CN), relative ischemia reperfusion group (IR), exercise preconditioning group (EP) and Exercise preconditioning + relative ischemia-reperfusion group (EI). We detected the third loading exercise time, the levels of MDA in serum in vivo experiment and the Cardiac function parameter, the levels of MDA in coronary effluent in vitro experiment.

RESULTS(1) The vivo experiment: The third loading exercise time of EI group [(71.67 +/- 9.00) min] increased significantly compared with that of IR group [(58.67 +/- 4.13) min] (P < 0.05); The levels of MDA in serum of EP group (107.00 +/- 35.99) micromol/L and EI group [(152.23 +/- 29.94) micromol/L] decreased significantly contrasted to IR group (313.20 +/- 43.40 micromol/L) (P < 0.05). (2) The vitro experiment: The PRP (heart rate * left ventricular developed pressure) in reperfusion period of CN group and EP group were stable relatively, while it reached the peak after 30 minutes and almost recovered to the level before ischemia in EI group. The parameter of IR group recovered slightly but was lower significantly than that before ischemia. There was significant difference between the recovery rate of Cardiac function of EI group and that of IR group. The increase of MDA in coronary effluent after Ischemia-reperfusion of EP group (0.34 +/- 0.24 micromol/L) and EI group [(0.41 +/- 0.26) micromol/L] decreased significantly contrasted to that of IR group [(1.27 +/- 0.52) micromol/L] (P < 0.05).

CONCLUSIONEP has the obvious delayed protection from the relative myocardial ischemia-reperfusion injury.