Exercise Preconditioning to Improve Myocardial Ischemia Tolerance Via the NO-PKC-KATP Signaling Pathway

Abstract

Background: Exercise preconditioning (EP) has a similar effect on ischemic preconditioning. Yet the specific endogenous trigger substance, intermediary substance and effect substance involved in EP have yet to be fully defined.Methods: 32 SD rats were divided into four groups: group A (control sham operation group); group B (control ischemia/reperfusion (I/R) model group); group C (train and I/R model group); and group D (train, inhibitor, and I/R model group). Rat model of acute endurance exercise was established. Then, in vivo I/R experiment and index test of the serum myocardial enzymes, the heart functions, Kir6.1 and Kir6.2 gene expressions and NOS and PKC protein expressions were carried out.Results: Compared with the A group, the heart function of the B group decreased significantly, and the serum myocardial enzymes increased significantly. Compared with the B group, the C group had less heart function decline and less myocardial injury. Injection L-NAME attenuated the cardioprotection induced by exercise preconditioning. B group's PKC protein expression was higher than the A group's; the C group's PKC protein expression was significantly higher than the B group's, and the D group's PKC protein expression was significantly lower than the C group's. In addition, the B group's Kir6.1 and Kir6.2 gene expressions were higher than the A group's; the C group's Kir6.1 and Kir6.2 gene expressions were significantly higher than the B group's, and the D group's Kir6.1 and Kir6.2 gene expressions were significantly lower than the C group's.Conclusions: Moderate intensity endurance exercise can induce a cardioprotective effect on I/R myocardium. Exercise preconditioning induces myocardial protective function via the NO-PKC-KATP signaling pathway.