Dietary fish oil (n-3 PUFA) reduced myocardial oxygen consumption at any given work output and increased postischemic recovery of contractile function in isolated rat hearts.
Does a diet rich in n-3 PUFA from fish oil improve ventricular hemodynamics and myocardial oxygen consumption in male Wistar rats?
Dietary fish oil directly improves cardiac responses to ischemia and reperfusion by reducing myocardial oxygen consumption and increasing postischemic recovery in a rat model.
BACKGROUND: Regular fish consumption is associated with low cardiovascular disease morbidity and mortality. Fish oils modify cardiac membrane phospholipid fatty acid composition with potent antiarrhythmic effects. We tested the effects of dietary fish oil on ventricular hemodynamics and myocardial oxygen consumption (MVO2). METHODS AND RESULTS: Male Wistar rats were fed for 16 weeks on a reference diet rich in n-6 polyunsaturated fatty acids (PUFA), a diet rich in saturated animal fat (SAT), or a diet rich in n-3 PUFA from fish oil. Isolated working hearts were perfused with porcine erythrocytes (40% hematocrit) at 75 mm Hg afterload with variable preload (5 to 20 mm Hg) or with low coronary flow ischemia with maintained afterload, preload, and heart rate, then reperfused. MVO2 was low and coronary perfusion reserve high in n-3 PUFA hearts, and cardiac output increased with workload. The n-3 PUFA reduced ischemic markers-acidosis, K+, lactate, and creatine kinase-and increased contractile recovery during reperfusion. SAT hearts had high MVO2, low coronary perfusion reserve, and poor contractile function and recovery. Dietary differences in MVO2 were abolished by KCl arrest (basal metabolism) or ruthenium red (3.4 micromol/L) but not by ryanodine (1 nmol/L). Fish oil or ryanodine, but not ruthenium red, prevented ventricular fibrillation in reperfusion. CONCLUSIONS: Dietary fish oil directly influenced heart function and improved cardiac responses to ischemia and reperfusion. The n-3 PUFA reduced oxygen consumption at any given work output and increased postischemic recovery. Thus, direct effects on myocardial function may contribute to the altered cardiovascular disease profile associated with fish consumption.
Pepe et al. (2002) studied Myocardial ischemia and reperfusion (animal model). Diet rich in n-3 PUFA from fish oil vs. Reference diet rich in n-6 PUFA or diet rich in saturated animal fat was evaluated on Ventricular hemodynamics and myocardial oxygen consumption (MVO2). Dietary fish oil (n-3 PUFA) reduced myocardial oxygen consumption at any given work output and increased postischemic recovery of contractile function in isolated rat hearts.