TRIMETAZIDINE INHIBITS NEUTROPHIL ACCUMULATION AFTER MYOCARDIAL-ISCHEMIA AND REPERFUSION IN RABBITS

Interventions that inhibit neutrophil infiltration into myocardial tis sue after ischaemia and reperfusion are reported to reduce the size of the infarct. We examined whether administration of trimetazidine, whi ch is reported to reduce myocardial infarct size, affects this process . [In-111]Neutrophils and [I-125]albumin were administered intravenous ly (i.v.) to anaesthetized rabbits to allow measurement of cell accumu lation and changes in microvascular plasma protein leakage. A 30-min p eriod of coronary artery occlusion followed by 3-h reperfusion was use d, and the area at risk (AR) myocardium was defined by dye exclusion. Twelve rabbits received 2.5 mg/kg trimetazidine i.v., 10 min before co ronary artery occlusion; the 13 controls received saline. In the contr ol group, the number of [In-111]neutrophils/g tissue in the AR (30,591 +/- 6,725) was significantly greater than in the normal zone (NZ, 11, 519 +/- 1,605, p < 0.01). In the trimetazidine-treated group, the numb er of [In-111]neutrophils in the AR was significantly lower than in th e control group (12,717 +/- 1,958 [In-111]neutrophils/g, p < 0.01). Th ere was no significant difference in neutrophil content of the NZ (7,8 32 +/- 1,117 [In-111]neutrophils/g) in treated animals as compared wit h that in control. Accumulation of [In-111]neutrophils in response to intradermal administration of leukotriene B4, interleukin-8 (IL-8), or zymosan-activated plasma was not affected by the drug. The effect of trimetazidine on neutrophil accumulation into postischemic reperfused myocardium therefore does not appear to result from a direct action on the neutrophil.