EFFECT OF DIETARY ANTIOXIDANT TRACE-ELEMENT SUPPLY ON CARDIAC TOLERANCE TO ISCHEMIA-REPERFUSION IN THE RAT

Over a 10-week period, female Wistar rats received a diet containing v arious levels of four trace elements (Zn, Cu, Mn, Se), co-factors of a ntioxidant enzymes (superoxide dismutase SOD, glutathione peroxidase G Px), in order to examine the influence of supplementation or deficienc y of these elements (i) on tissue antioxidant enzyme defence systems, and (ii) on the susceptibility of the myocardium to ischemia-reperfusi on injury, At the end of the dietary treatment, hearts were perfused a t constant now (11 ml/min) before being subjected to 15 min of total g lobal normothermic ischemia, followed by reperfusion. The effects of t he various diets (deficient, standard or supplemented) were estimated by studying functional recovery of various cardiac parameters (left ve ntricular developed pressure LVDP, dP/dt(max), heart rate x LVDP) as w ell as ultrastructural tissue characteristics. Furthermore, SOD and GP x activities were measured before ischemia and at the end of the reper fusion period. Results suggest that: (a) the activity of antioxidant e nzymes increased or decreased significantly when diet was respectively supplemented with, or deficient in, trace elements, but was not furth er modified by an ischemia-reperfusion episode; (b) the recovery of ca rdiac function during reperfusion, and Ventricular myocardial ultrastr ucture were significantly improved under the influence of trace elemen t supplementation when compared to both standard and deficient groups. These results illustrate the protective effect of trace elements whic h are co-factors of antioxidant enzymes in limiting ischemia-reperfusi on induced injury, and suggest a possible use in the field of anti-isc hemic therapy. (C) 1995 Academic Press Limited