Abstract
BackgroundMyocardial ischemia-reperfusion (IR) injury is a leading cause of death all over the world, so developing practical approaches to promote cardioprotection against IR injury is essential. Exercise training is an effective strategy to improve cardioprotection. Hence, the purpose of this study was to investigate the effect of short-term preconditioning with two types of high-intensity interval training (HIIT) and moderate intensity continuous training (MICT) on klotho and TRPC6 mechanisms in cardioprotection.MethodsEighty Male Wistar rats (250–300 g) were randomly divided into 7 groups, including Control, HIIT, MICT, Sham, IR, HIIT+IR, and MICT+IR. Training was performed in 5 consecutive days. HIIT protocol consisted of running on the treadmill at intervals 85–90% vo2max that separated by slow intensity periods at 50–60% vo2max. MICT program was performed at 70% VO2max at the same running distance with HIIT groups. The cardiac IR injury was induced by LAD occlusion followed by reperfusion. ELISA kit was used in order to measure the plasma levels of klotho, LDH and CK-MB, and TRPC6 expression was determined using the western blot technique. Data were analyzed using one way ANOVA and Tukey’s post hoc tests.ResultsThe results of this study showed that both types of exercise training programs significantly increase plasma levels of klotho and reduce the infarct size and heart injury. In addition, the exercise training decreased the amount of TRPC6 channels expression during IR. However, the effect of HIIT on increasing the klotho and cardioprotection was greater compared to MICT.ConclusionsBased on the results, even a short-term of aerobic exercise training, especially HIIT, promotes cardioprotection against IR injury and decreases infarct size via an increase in klotho and attenuate of protein expression of myocardial TRPC6 during IR.
Highlights
Myocardial ischemia-reperfusion (IR) injury is a leading cause of death all over the world, so developing practical approaches to promote cardioprotection against IR injury is essential
As shown in the figure of TTC-stained (Fig. 1), the infarct size in IR group was 43.10 ± 3.35, but the results of this study indicated that 5 consecutive days of aerobic exercise training with both high-intensity interval training and moderate-intensity continuous training decreased infarct size in rats (p < 0.001; Fig. 1)
The results indicated that the effect of high-intensity interval training (HIIT) on reducing the infarct size was higher than the moderate intensity continuous training (MICT) (34 and 20%, respectively)
Summary
Myocardial ischemia-reperfusion (IR) injury is a leading cause of death all over the world, so developing practical approaches to promote cardioprotection against IR injury is essential. When the heart is regularly exposed to mild IR without cell death (such as conditions caused by exercise training), it leads to augment cardioprotection through the preconditioning process [4, 5] In this regard, numerous studies show that regular exercise, even short-term of exercise training (1, 3 and 5 sessions) [4, 6,7,8,9], is one of the practical approaches of preconditioning to achieve cardioprotection and reduce the risk of IR-induced injury and death [4, 10]. The increased level of cytosolic calcium through various mechanisms, including activating calpain, facilitating production of mitochondrial ROS, mPTP opening, dissipate of mitochondrial membrane potential and further impairs ATP production, leads to mitochondrial dysfunction and increase cellular injury and cell death [17,18,19]. It is likely that preventing calcium overload by the change in calcium channels and calcium handling proteins and improving the antioxidant status to be the main mechanisms of exercise-induced cardioprotection [3, 11, 12]
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