[The effects of alpha-linolenic acid on the functioning of the isolated heart during acute myocardial ischemia/reperfusion].

Many studies indicate that dietary omega-3 polyunsaturated fatty acids (PUFAs) have the cardioprotective properties. But majority of experiments were carried out with using omega-3 PUFAs from marine fish oil. The purpose of this study was to determine effects of the plant-derived omega-3 PUFA (alpha-linolenic acid (a-LA) on postischemic myocardial dysfunction, lipid peroxidation and antioxidant enzymes activity. Male Wistar rats (250-300 g) were divided into 4 groups (n = 10-12 each). In control group (1) were intact rats. The hearts from 2-nd group of animal were exposed to 20 min of global ischemia followed by 40 min reperfusion according to the Langendorff technique. The 3-rd and 4-th groups of animal received of the plant-derived oil (a-LA), which is a precursor of eicosapentaenoic acid and was used as a dietary supplement in dose 0.1 mg/kg per day for 4 weeks. The hearts from 4-th group of animal were also exposed to ischemia/ reperfusion. Analysis of myocardial phospholipid fatty acid content showed that consumption of the plant-derived 6-LA for 4 weeks changes fatty acid profile through incorporation of b-LA in cell membranes. It also reduced content of omega-6 PUFAs in membrane phospholipids. In 3-rd group content of a-LA and EPA were increased by 1.5- and 3.5-times, respectively, whereas content of AA was reduced by 1.7-times. The development of ischemia/ reperfusion in 2-nd group caused increase of free AA content in heart tissue by 3.5-times, whereas in 4-th group this increase was only by 1.4-time. Ischemia/reperfusion of the isolated rat heart in 4-th group was accompanied by reduced leukotriene C4 and thromboxane B2 production in 3-times and 1.9-times, respectively in comparison to 2-nd group. The time of myocardial function recovery after ischemia (heart rate, left ventricular development pressure), was shorter compare to 2-nd group. Also in 4th group end-diastolic pressure and coronary perfusion pressure during reperfusion period were significantly lower. Dietary omega-3 PUFAs resulted in remarkable decrease of reperfusion arrhythmias in 4-th group (in 3.8-times) and limited the oxidative stress through decrease free radical and lipid peroxidation production. In this group of animals the activity of antioxidant enzymes (superoxide dismutase and catalase) after ischemia/reperfusion were higher than in 2-nd group. We suggest that dietary supplement of the plant-derived alpha-LA for 4 weeks have cardioprotective effects similar to the effects of fish oil.