Cardiac troponin T as a marker of myocardial damage caused by antineoplastic drugs in rabbits

Anthracycline derivatives are among the most effective antineoplastic drugs but their therapeutic use is limited by their adverse effects. The cardiac side-effects of antineoplastic drugs were investigated in rabbits in vivo from the viewpoint of release of cardiac troponin T (cTnT) measured by Elec sys Troponin T STAT immunoassay (Boehringer Mannheim, Germany). No increase in cTnT was found following administration of a single dose of daunorubici n (3 mg/kg i.v., n = 4). During development of daunorubicin-induced cardiom yopathy (daunorubicin 3 mg/kg i.v., once a week; maximum nine administratio ns, n = 7), the levels of cTnT were within the physiological range (i.e. cT nT < 0.1 mu g/l) at the beginning of the experiment and before and after th e 5th administration, but the pathological values of cTnT after the 8th adm inistration in 43% animals (0.22 +/- 0.08 mu g/l) correlated with their pre mature death. In the control group, the levels of cTnT were always lower th an 0.1 mu g/l during the experiment. Following administration of a new anti neoplastic drug - Oracin {6-[2-(2-hydroxyethyl) aminoethyl]-5,11-dioxo-5,6- dihydro-11H-indeno [1,2-c]-isoquinoline hydrothloride, 10 mg/kg i.v., once weekly, ten administrations, n = 7}, there was no increase in cTnT levels. These findings correlated with the PEP: LVET index, histological examinatio n and no animal succumbing to premature death. It is possible to conclude t hat cTnT is a useful marker for the prediction of experimentally induced an thracycline cardiomyopathy and for the evaluation of cardiotoxic (and, poss ibly, cardioprotective) effects of new drugs in rabbits.