Abstract P48: Preconditioning with Periodic Acceleration Significantly Decreases Infarct Size and Arrhythmias after Left Ventricular Ischemia Reperfusion Injury in Rats
BACKGROUND: Whole body periodic acceleration (pGz) is the sinusoidal head-foot motion in the spinal axis. pGz increases pulsatile vascular shear stress to the endothelium, activates endothelial nitric oxide synthase (eNOS) thus promoting increased release of nitric oxide (NO) in pigs, sheep, rats, isolated aorta, and humans. pGz is cardioprotective via NO release 1 hr prior to CPR or during CPR in pigs with induced ventricular fibrillation. The purpose of this study was to ascertain whether acute and chronic pGz preconditioning is cardioprotective in myocardial ischemia reperfusion (I/R) injury in rats as measured by infarction size, and arrhythmias.
METHODS: Unsedated, restrained, male rats (310±9 g, n=16) were preconditioned with pGz (f=6 cps, a=3.4 m/s2). Rats were randomized to: a) pGz 2 hr for 1 day prior to I/R (PRE-pGz 1D) n=4, b) pGz 2 hrs per day for 3 days prior to I/R (PRE-pGz 3D) n=6 and c) Control (C) n=6. Then, they were anesthetized and underwent focal I/R injury by left coronary artery ligation for 30 minutes followed by 120 min of reperfusion. ECG, and aortic pressure were monitored and infarct size calculated as % area at risk.
RESULTS: PRE-pGz 3D had an infarct sparring effect of 77% of C. Both 1 and 3 days PRE-pGz significantly attenuated ventricular arrhythmias during reperfusion. Figure⇓ below shows % infarct for all groups, †P<0.001 PRE-pGz 3D vs. C, *P<0.001 PRE-pGz 1D vs. C, and representative areas of infarct (INF) and at risk (AAR) in PRE-pGz 3D and C.
CONCLUSIONS: pGz preconditioning in rats significantly reduces infarct size and attenuates ventricular arrhythmias. This simple and non-invasive method of cardioprotection for I/R injury warrants human investigations.