Beneficial effects of omega-3 fatty acid treatment on the recovery of cardiac function after cold storage of hyperlipidemic rats

Cardiac effects of omega-3 polyunsaturated fatty acids (PUFAs) were studied in female Wister rats fed a standard diet (control [C] diet) or a high-cho lesterol (HC) diet. Subgroups of rats from these groups were treated with e icosapentaenoic acid-E (EPA) or docosahexaenoic acid-95E (DHA) for 5 weeks. Although plasma total cholesterol (TC) and triglyceride (TG) levels were h igher in each group fed the HC diet versus each group fed the C diet, EPA a dministration with the HC diet (HC + EPA) significantly (P < .05) reduced t hese levels. An isolated working-heart preparation was used to determine ca rdiac function. Cardiac output (CO) was lower in rats fed the HC diet and H C + DHA versus any of the groups fed the C diet (P < .05). In addition, lef t ventricular (LV) maximum differentiation of pressure-time curve (dp/dt) w as lower in the rats fed the HC diet versus any of the C diet groups (P < . 05). After evaluation of cardiac function in each rat, the heart was stored in a histidine-tryptophanketoglutarate solution for 8 hours at 4 degrees C . The heart was then reperfused, and recovery of cardiac function was evalu ated. No significant differences were observed for post-preservative cardia c function within the C diet groups. However, within the HC diet groups, HC + EPA significantly (P < .05) improved the recovery of cardiac function. I n addition, HC f DHA also significantly (P < .05) improved the recovery of coronary flow (CF) and LV dp/dt. No significant differences were observed f or plasma TC and TG concentrations in the C diet groups. EPA administration significantly decreased cardiac levels of palmitic, oleic, and linoleic ac ids in the HC diet groups. No significant differences were observed for car diac levels of free fatty acids (FFAs) within the C diet groups, Cardiac EP A and DHA levels were significantly (P < .05) elevated in EPA- or DHA-treat ed rats compared with the other diet-fed rats. Cardiac EPA levels were also elevated in DHA-treated rats compared with untreated rats (P < .05). These results suggest that EPA attenuates coronary and myocardial preservation i njuries through an increase in serum lipids and an accumulation of myocardi al FFAs resulting from a HC diet. Copyright (C) 1999 by W.B. Saunders Compa ny.