Metabolic disorder in myocardiac intracellular free calcium after thermal injury

Cutaneous burn trauma causes functional inhibition of the heart, but the me chanism is unclear. Using a high dissociation constant (K-D) calcium indica tor TF-BAPTA and F-19 MR spectroscopy, the relationship between the changes of cytosolic free calcium and cardiac function after burn trauma was exami ned. Sprague-Dawley rats received scald (43% TBSA) or sham burns. Twenty-fo ur hours later. the hearts were excised and perfused by the Langendorff met hod with a modified phosphate-free Krebs-Henseleit bicarbonate buffer. Left ventricular developed pressure (LVDP) was recorded through a catheter atta ched to an intraventricular balloon. At the same time, P-31 and F-19 nuclea r magnetic resonance (NMR) spectroscopy was perforined before and after TF- BAPTA loading. LVDP of the heart from burned rats was 40% less than in sham burn rats (65 +/-6 vs 110 +/- 12 mmHg, P < 0.01). Cytosolic free calcium i ncreased about four-fold in those hearts from the burn group compared to th e sham burn group (0.807<plus/minus>0.192 vs 3.891 +/-0.929 muM). Loading T F-BAPTA in those hearts only caused about a 15-20% decrease in LVDP. PCr/Pi ratio also decreased significantly with this loading, but ATP signals were not affected. In conclusion, the inhibition of cardiac contractility cause d by burn trauma correlated with the overload of cytosolic free calcium in the heart. (C) 2001 Elsevier Science Ltd and ISBI. All rights reserved.