[Influence of Fatty Acids on Oxygen Consumption in Isolated Cardiomyocytes of Rats with Ischemic or Diabetic Heart Disease].

BACKGROUND: one of the reasons of violation of the functional viability of the myocardium is considered to be the oxygen deprivation and lack of energy. The reason is the inhibitory effect of fatty acids on glucose oxidation. Recently, however, new data have been published proving the need for fatty acids and their importance in the maintenance and regulation of the functional activity of the myocardium in chronic pathology. OBJECTIVE: to investigate the influence of free polyunsaturated and saturated fatty acids (FA) on the oxygen uptake of isolated cardiomyocytes in intact rats and animals with ischemic or diabetic heart disease. METHODS: the executed non-randomized controlled study. It includied 3 groups of male rats of Wistar line (weight 250-300g) with 10 animals in each group. Myocardial infarction ("heart attack" group) was caused by ligation of the left coronary artery, diabetes ("diabetes" group)--by intraperitoneal injection of streptozotocin, and "control" group (intact animals). Myocardial infarction caused by ligation of the left coronary artery, and diabetes by intraperitoneal injection of streptozotocin. Isolated cardiac myocytes were obtained by the enzymatic method. Oxygen consumption was assessed polarographically at different saturation incubation medium with oxygen ([O2] ≤ 8 mg/l and ([O2] ≥ 16 mg/l). Arachidonic and palmitic acids were applied as fatty acids. RESULTS: It is established that the introduction of the incubation medium 20 µm arachidonic or palmitic fatty acid significantly increased the oxygen consumption of intact cardiomyocytes of rats. Both at the ischemic and at the diabetic injury to the heart the opposite result was obtained. The most pronounced decrease in oxygen consumption was indicated in the group with diabetes mellitus. CONCLUSION: The inhibitory effect of LCD on the rate of oxygen consumption may be associated with the influence of the ischemic or diabetic injury to the heart on the barrierfunction ofmitochondrial membranes of cardiomyocytes, the activity of membrane-associated enzymes and their associated processes.

Effect of Arachidonic Acid on the Rate of Oxygen Consumption in Isolated Cardiomyocytes from Intact Rats and Animals with Ischemic or Diabetic Injury to the Heart.

We studied the rate of oxygen consumption by isolated cardiomyocytes from intact rats and animals with experimental myocardial infarction or streptozotocin-induced diabetes mellitus. The measurements were performed in standard incubation medium under various conditions of oxygenation and after addition of arachidonic acid (20 µmol/liter). Under normoxic conditions, arachidonic acid improves respiration of cardiomyocytes from intact animals, but reduces this parameter in cells isolated from animals with pathologies. The intensity of O2 consumption by cardiomyocytes from intact rats and animals with pathologies was shown to decrease during hypoxia. Addition of arachidonic acid aggravated inhibition of respiration for cardiomyocytes from intact rats and specimens with myocardial infarction, but had no effect in diabetes mellitus. The effect of arachidonic acid on oxygen consumption rate is probably mediated by a nonspecific mechanism realized at the mitochondrial level.