Effect of iloprost (ZK 36 374) on membrane integrity in ischemic rabbit hearts

The hypothesis that prostacyclins exert a membrane stabilizing action on the ischemic myocardium was examined in isolated rabbit hearts by measuring the elimination half-time of labelled catabolites after injection of 17-(131I)-heptadecanoic acid. During normoxia, a rapid washout of labelled lipids was observed along with a slower exponential elimination of I- from beta-oxidation. After 90 min of ischemia, lipid washout was increased over 6-fold. Infusion of iloprost (1.1 nmol/min) significantly reduced the lipid washout half-time. Iloprost preserved functional myocardial integrity as evidenced by a greater recovery of left ventricular pressure and attenuation of the increase in coronary resistance after reperfusion. These results indicate that the poor recovery of the heart after ischemia is associated with significant changes in membrane integrity and permeability. These data support the hypothesis that the biochemical and functional myocardial preservation by prostacyclin(s) is by a membrane stabilizing mechanism.