Influence of omega-3 fatty acid treatment on cardiac phospholipid composition and coronary flow of streptozocin-diabetic rats.

Cardiac effects of omega-3 fatty acid treatment were studied in streptozocin (STZ)-induced (55 mg/kg intravenously [IV]) diabetic male Wistar rats. Nondiabetic control and STZ-diabetic animals were treated with Promega (0.5 mL/kg/d; Warner-Lambert, Morris Plains, NJ) for a period of 4 weeks beginning 2 weeks after either vehicle or STZ injection. Plasma glucose, triglyceride, and cholesterol concentrations were significantly (P < .05) elevated in diabetic animals; omega-3 fatty acid treatment did not significantly affect these parameters. An isolated working heart preparation was used to determine aortic and coronary flow rates in control, diabetic, treated control, and treated diabetic animals. Aortic and coronary flow rates of untreated STZ-diabetic rats were significantly (P < .05) lower than those of controls over a range of left atrial filling pressures (7.5 to 20 cm water). Both aortic and coronary flow rates of omega-3 fatty acid-treated diabetic animals were significantly (P < .05) increased above those of untreated diabetic rats. Aortic and coronary flow rates of treated diabetic rats paralleled those of control animals; omega-3 fatty acid treatment did not affect aortic or coronary flow rates of control animals. Cardiac phosphatidylcholine (PC) and phosphatidylethanolamine (PE) and sarcoplasmic reticulum (SR) total phospholipid were isolated and the acyl composition was determined. Stearic acid and C22:4, n-6 were significantly reduced in cardiac PE of diabetic animals. Relative to PE acyl species of untreated nondiabetic controls, treated diabetic PE had increased eicosapentaenoic acid (EPA) and decosahexaenoic acid (DHA) and reduced C22:4, n-6 levels.(ABSTRACT TRUNCATED AT 250 WORDS)