Omega 3 has a beneficial effect on ischemia/reperfusion injury, but cannot reverse the effect of stressful forced exercise

Background and aimThe beneficial effects of exercise in reducing the incidence of cardiovascular diseases are well known. Several studies have demonstrated that forced exercise (FE) could activate a stress response similar to a restrain stress. Previous studies suggest that heart protection to ischemic events would be improved by an omega 3 free fatty acid (ω3-FFA)-enriched diet. Here, we investigate the impact of stressful FE and an omega 3-FFA-enriched diet on cardiac tolerance to ischemic events over one month.Methods and resultsTwenty-four Wistar rats were randomly assigned to one of the following protocols: 1) Sedentary (SED) animals who were regularly fed; 2) sedentary animals who were given 1 ml/day of fish oil for one month; 3) FE + ω3-FFA rats who were given 1 ml/day of fish oil and forced to run on a motorized wheel for 30 min every day, both for one month; and 4) FE animals were forced to exercise as group 3 and fed with a regular diet. At the end of the treatments an isolated heart preparation was performed.After a 30 min global ischemic event and 2 h reperfusion, hearts of sedentary-ω3 animals recovered about 37% of left ventricular developed pressure, whereas FE, ω3 + FE and CTRL-SED animals recovered only about 15%, 5% and 8% respectively. Similarly, heart infarct size was significantly lower in sedentary-ω3 animals compared to animals in the three other groups.ConclusionsResults indicate that one month of treatment with an ω3-FFA-enriched diet improves cardioprotection upon ischemic events, whereas FE leads to a reduced heart tolerance to ischemic events, which cannot be reversed by an ω3-FFA diet.