Diminution of "reperfusion injury" in reperfused ischemic myocardium by phenothiazines. A quantitative morphological study.

The effect of pretreatment by phenothiazines--Chlorpromazine (CPR) /Spofa/ and Trifluoperazine (TFP) /Smith Kline and French/ on reperfusion injury of ischemic myocardium were studied. Reperfusion of ischemic myocardium following an ischemic period exceeding 40 min resulted in morphological, physiological and biochemical changes identical with those induced by enhanced cytosolic Ca2+ concentration. Left descending coronary ligation was performed on 70 dogs divided into four group. Group I: permanent occlusion (5 dogs--60 min, 5 dogs--120 min, 5 dogs--180 min); group II: 15 dogs (60 min occlusion + 120 min reperfusion); group III: 20 dogs (60 min occlusion, 15 mg CPR, reperfusion 120 min); group IV: 20 dogs (60 min occlusion, 2 mg TFP + 120 min reperfusion). CPR or TFP were administered 30 min after the ligation. The effect of drugs was quantified on tetrazolium stained gross sections and studied from physiological, biochemical and ultrastructural points of view. Treatment of animals with phenothiazines, known as calmodulin inhibitors, considerably improved the ultrastructure of myocytes in area at risk, and allowed for the recovery of at least 60 per cent of injured myocytes after reflow restoration. Ultrastructural findings tightly correlate with physiological and biochemical results.