Short-Term Fasting Reduces the Extent of Myocardial Infarction and Incidence of Reperfusion Arrhythmias in Rats
Abstract
The effect of three-day fasting on cardiac ischemic tolerance was investigated in adult male Wistar rats. Anesthetized open-chest animals (pentobarbitone 60 mg/kg, i.p.) were subjected to 20-min left anterior descending coronary artery occlusion and 3-h reperfusion for infarct size determination.
Ventricular arrhythmias were monitored during ischemia and at the beginning (3 min) of reperfusion. Myocardial concentrations of beta-hydroxybutyrate and acetoacetate were measured to assess mitochondrial redox state.
Short-term fasting limited the infarct size (48.5 +/- 3.3 % of the area at risk) compared to controls (74.3 +/- 2.2 %) and reduced the total number of premature ventricular complexes (12.5 +/- 5.8) compared to controls (194.9 +/- 21.9) as well as the duration of ventricular tachycardia (0.6 +/- 0.4 s vs. 18.8 +/- 2.5 s) occurring at early reperfusion. Additionally, fasting increased the concentration of beta-hydroxybutyrate and beta-hydroxybutyrate/acetoacetate ratio (87.8 +/- 27.0) compared to controls (7.9 +/- 1.7), reflecting altered mitochondrial redox state.
It is concluded that three-day fasting effectively protected rat hearts against major endpoints of acute I/R injury. Further studies are needed to find out whether these beneficial effects can be linked to altered mitochondrial redox state resulting from increased ketogenesis.