BENEFICIAL EFFECT OF CAPTOPRIL AGAINST ISCHEMIA-REPERFUSION INJURY INISOLATED GUINEA-PIG HEARTS

The study was designed to clarify whether captopril, an angiotensin-co nverting enzyme inhibitor, will reduce the injury of global ischaemia and reperfusion after cardioplegic arrest in isolated guinea pig heart s, in a modified Langendorff model. The hearts were randomly allocated into four groups (n = 10 in each) and subjected to 90 min of normothe rmic global ischaemia, followed by 30 min of reperfusion; in all group s, cardioplegic arrest was achieved by administering St. Thomas's Hosp ital cardioplegic solution (STHCS). The first group was utilized as th e control group. In the second group, captopril (200 mu mol/L) was add ed to STHCS. In the third group, oral pretreatment was carried out (0. 3 mg/kg captopril was given twice a day for 10 days). In the fourth gr oup, oral pretreatment was achieved and captopril-enriched solution wa s applied in the first 5 min of reperfusion. Although the study groups showed better recovery of contractility than the control group, in th e fourth group the hearts had the best left ventricular contractile fu nction, where contractile force (g contractility/g heart weight) was 5 5.4% +/- 3.8% of the preischaemic values. Groups I, II, and III achiev ed 31.0% +/- 3.2%, 41.6% +/- 3.8%, and 48.3% +/- 3.9% of their preisch aemic contractile force values. Creatine kinase leakage was significan tly lower and postischaemic coronary flows, too, were significantly hi gher in the fourth group. Coronary flow after reperfusion increased fr om 48.5 +/- 6.7 to 65.2 +/- 7.1 ml/min g heart in group 4 (p<0.05). My ocardial lipid peroxides and glutathione contents showed that there wa s a correlation between the depletion of myocardial glutathione conten t and increased lipid peroxidation. These preliminary results showed t hat: the addition of captopril to reperfusion solution and oral precon ditioning improved post-ischaemic myocardial function and decreased my ocardial injury.