RELEASE KINETICS AND CORRELATION WITH HEMODYNAMIC DYSFUNCTION OF CARDIAC TROPONIN-T IN CORONARY EFFLUENT FROM ISOLATED RAT HEARTS DURING REPERFUSION

Previously, we reported that cardiac troponin T (TnT) can be detected and measured in coronary effluent from isolated rat hearts during hypo xia. The present study was designed to evaluate the release kinetics o f TnT from post-ischemic rat hearts. Using the Langendorff technique, the hearts were reperfused for 4h after 20 min or 60 min of global isc hemia. Coronary flow was measured by timing the collection of the coro nary perfusate that dripped from the hearts, and left ventricular pres sure (LVP) was monitored continuously during the experiments. The amou nt of TnT released in 1 min was compared with the release of creatine kinase (CK) and lactate dehydrogenase (LD). The release kinetics of CK and LD showed a monophasic pattern and the levels at 4h after reperfu sion returned to baseline levels. By contrast, the release kinetics of TnT showed a small peak followed by a larger and more sustained peak. There were good negative correlations between developed pressure of L VP and both SIGMA TnT and the amount of TnT released within 1 min at 4 h after reperfusion. These results indicate that the release kinetics of TnT is different from that of CK and LD during reperfusion, and fur ther that cardiac TnT is a useful indicator of myocardial cell damage and can be used to evaluate the degree of myocardial cell damage in bo th the early and late phase of acute myocardial infarction.