ABC | Volume 112, Nº1, January 2019

Original Article Whole-Body Vibration Training Increases Myocardial Salvage Against Acute Ischemia in Adult Male Rats Shahnaz Shekarforoush 1 and Mohammad Reza Naghii 2 Islamic Azad University, 1 Arsanjan Branch, Fars – Iran Sport Physiology Research Center, Baqiyatallah University of Medical Sciences, 2 Teerã – Iran Mailing Address: Shahnaz • Arsanjan - University Blv. Arsanjan Branch, Islamic Azad University, 7188855989, Shiraz, Fars – Iran E-mail: sh.shekar@yahoo.com , shek@iaua.ac.ir Manuscript received March 20, 2018, revised manuscript June 19, 2018, accepted July 23, 2018 DOI: 10.5935/abc.20180252 Abstract Background: Whole body vibration training (WBV) is a new training program, which is safe and effective. It can be followed by the public. However, data on the safety and efficacy of vibration on myocardial ischemia reperfusion (IR) injury are lacking. Objective: To examine the effect of WBV on the tolerance of the myocardium to acute IR injury in an experimental rat model. Methods: Twenty-four male Wistar rats were divided into control and vibration groups. Vibration training consisted of vertical sinusoidal whole body vibration for 30 min per day, 6 days per week, for 1 or 3 weeks (WBV1 and WBV3 groups, respectively). All the rats were submitted to myocardial IR injury. Myocardial infarct size and ischemia-induced arrhythmias were assessed. Differences between variables were considered significant when p < 0.05. Results: No differences were observed between the groups regarding the baseline hemodynamic parameters. Infarct size was smaller in the experimental group (control, 47 ± 2%; WBV1, 39 ± 2%; WBV3, 37 ± 2%; p < 0.05, vs. control). Vibration produced a significant decrease in the number and duration of ventricular tachycardia (VT) episodes compared to the control value. All ventricular fibrillation (VF) episodes in the vibration groups were self-limited, while 33% of the rats in the control group died due to irreversible VF (p = 0.02). Conclusion: The data showed that vibration training significantly increased cardiac tolerance to IR injury in rats, as evidenced by reduction in the infarct size and cardiac arrhythmias, and by facilitating spontaneous defibrillation. (Arq Bras Cardiol. 2019; 112(1):32-37) Keywords: Rats Wistar; Body Composition; Vibration; Osteoporosis/prevention and control; Blood Viscosity; Ischemia; Cardiovascular Diseases; Ischemic Preconditioning. Introduction Whole body vibration training (WBV) has been recently proposed as an exercise training method with a potential for improving body composition and preventing osteoporosis and bone mass loss. 1 In recent years, some studies have shown that WBV may be a beneficial training mode in patients with multiple sclerosis, 2 type 2 diabetes, 3 chronic obstructive pulmonary disease, 4 and heart transplant recipients. 5 The effects of WVB on the cardiovascular system were investigated in a number of published studies. Decreased arterial stiffness after WBV can reduce the risk of cardiovascular disease. 6,7 An experiment conducted by Robbins et al. 8 showed a significant increase in blood flow velocity with no significant changes in heart rate, blood pressure or peripheral skin temperature. Increased muscle blood volume and blood flow velocity after vibration exercise were attributed mainly to the effect of vibrations in reducing blood viscosity and increasing its velocity through the arteries. 9 These findings indicate that WBV may represent a mild form of exercise for the cardiovascular system. 10 Cardiovascular disease (CVD), which is induced by ischemia, is the leading cause of death worldwide. Restoration of blood flow, after a period of ischemia, can elicit pathological processes that exacerbate injury due to the ischemia itself . 11 Preconditioning describes a pretreatment or premaneuver that is able to adapt the myocardium to ischemic stress. We have demonstrated some preconditioning interventions in previous experiments, reducing infarct size and arrhythmias. 12,13 The cardioprotective effect of exercise preconditioning was reported as a reduction in infarct size in previous studies. 14,15 Accumulating evidence indicates that both short-term (i.e. 1-5 days) and long-term (i.e. weeks to months) exercise can protect the heart during an ischemia-reperfusion (IR) insult. While much is currently known about exercise preconditioning, to our knowledge, the effect of whole-body vibration on IR injury has not been investigated. Thus, the purpose of this study was to determine whether the vibration exercise would be able to reduce infarct size and arrhythmia during IR injury in an experimental rat model. 32