BACKGROUND - This experiment sought to determine the effects of fish oil on superoxide anion production in the myocardium and coronary arteries of atherosclerotic monkeys. Recent evidence indicates that dietary supplementation with fish oil preserves normal vasomotion of atherosclerotic coronary arteries and reduces damage to the myocardium after ischemia and reperfusion, although the mechanisms remain unclear.
METHODS AND RESULTS - Adult male cynomolgus monkeys were fed an atherogenic diet with (n = 15) or without (n = 15) half the fat calories from fish oil. After 12 months, chemiluminescence of lucigenin was used to measure superoxide anion production in coronary arteries and myocardium after 1 hour of ischemia and 2 hours of reperfusion. The signals were calibrated with known quantities of xanthine and xanthine oxidase. Superoxide anion production in ischemic myocardium was (mean +/- SEM, nmol/mg dry wt per minute) 1 +/- 1 and 4 +/- 1 in monkeys fed fish oil and not fed fish oil, respectively (P < .05). Superoxide anion production in coronary arteries not exposed to ischemia and reperfusion was (nmol/mg dry wt per minute) 4 +/- 1 and 8 +/- 2 in monkeys fed fish oil and not fed fish oil, respectively (P < .05). Superoxide anion production in coronary arteries was (nmol/mg dry wt per minute) 5 +/- 2 and 16 +/- 3 in monkeys fed fish oil and not fed fish oil after ischemia and reperfusion, respectively (P < .05).
CONCLUSIONS - Dietary supplementation with fish oil reduced vascular superoxide anion production and prevented the increase in vascular and myocardial superoxide anion production that accompanied ischemia and reperfusion. These phenomena may underlie some of the beneficial cardiovascular effects of fish oil.