Effects of pharmacologic preconditioning by natural honey on arrhythmias and infarct size in isolated heart

In this study, prophylactic effects of natural honey as a pharmacologic preconditioning agent on ischemia/reperfusion (I/R) induced cardiac arrhythmias and infarct size were investigated in isolated rat heart. Isolated rat hearts were mounted on a Langendorff apparatus then subjected to 30min regional ischemia followed by 120minreperfusion. In control group, the hearts were perfused by a modified Krebs-Henseleit solution throughout the experiment, however, in the test groups they were perfused by enriched Krebs solution with natural honey (0.25, 0.5 and 1%) 10min before to 10min after ischemia. The arrhythmias were analyzed based on the Lambeth conventions. The infarct size was determined by Triphenyltetrazolium chloride and planimetry methods. At the ischemia, the total number of ventricular ectopic beats (VEBs) in the control group was 667±116 while perfusion of natural honey (0.25, 0.5 and 1%) reduced it to 128±35 (p<0.01), 161±35 (p<0.01) and 303±94 (p<0.05), respectively. The number of ischemic ventricular tachycardia (VT) and the time spent in VT were significantly lowered by the same concentrations. Honey (0.25 and 0.5%) decreased the incidence of VT from 100% (control) to 13% (p<0.001) and 25% (p 0.01), respectively. During reperfusion phase, the number of VEBs and VT were significantly reduced by all used concentrations. In addition, honey (0.25%) significantly decreased the incidence and time spent for reversible ventricular fibrillation. Moreover, perfusion of honey (0.25, 0.5 and 1%) reduced infarct size from 46.3±2.9% (control value) to 3.3±1.3, 9.2±1.9 and 11.7±2.2%, respectively (p<0.001 for all). The results of this study showed antiarrhythmic and anti infarct properties of natural honey as a preconditioning agent against I/R injuries in isolated rat heart. Probably, antioxidant activity of honey, scavenging of free radicals and presence of energy sources such as glucose may involve in these cardioprotective effects.