Effect of iloprost on serum creatine kinase and lactate dehydrogenase isoenzymes after isoprenaline-induced cardiac damage in rats.

The effect of iloprost was investigated in an experimental model of cardiac damage in rats after isoprenaline (isoproterenol) treatment. Iloprost was administered by continuous subcutaneous infusion at a dose of 0.44 micrograms/kg body weight (b.w.)/min over a total period of 9 days. On day 8, 5 mg isoprenaline/kg b.w. was applied subcutaneously to induce the cardiac damage. The determinations of creatine kinase (CK, EC 2.7.3.2) and CK isoenzymes, lactate dehydrogenase (LDH, EC 1.1.1.27) and LDH isoenzymes as well as a-hydroxybutyrate dehydrogenase (a-HBDH, no EC) were performed 2, 6 and 24 h after isoprenaline application. Immediately after the last blood sampling, the animals were sacrificed and the hearts were examined histologically. Iloprost-pretreated animals showed a reduction in the rise in heart-specific isoenzymes CK-MB and LDH1-3 in the serum after isoprenaline application. A decrease in isoenzymes CK-BB and LDH4-5 in the serum was also observed in iloprost-pretreated rats. However, no difference could be detected histologically in the extent of myocardial necrosis between animals treated with isoprenaline alone or in combination with iloprost. These results suggest a biochemical cardioprotective effect of iloprost in this rat model after isoprenaline application and the lack of correlation with histological findings is discussed.