Prevention of lactate production and myocyte injury in isolated rat hearts perfused with perfluorochemical emulsion

The ability of an oxygenated perfluorocarbon (PFC) emulsion to prevent early signs of myocardial cell stress associated with Krebs-Henseleit (KH) perfusion was evaluated in isolated rat hearts supported in a Langendorff apparatus. Throughout the two-hour perfusion, hearts in both perfusion groups had similar left ventricular pressure and rates of left ventricular pressure development (dP/dt). After 2 h, coronary perfusate flow was 6.6 ± 1.0 ml/min in the KH group and 2.2 ± 0.1 ml/min in the PFC group. Oxygen content was 1.5 ± 0.1 ml/100 ml and 3.4 ± 0.1 ml/100 ml, in KH and PFC groups, respectively. Perfusate lactate levels rose from zero to 24.0 + 8.0μg/ml in the KH group and to 10.0 ± 3.0 μg/ml in the PFC group. Reduction in myocardial cell injury and in total calcium content was also oberserved in hearts perfused with PFC emulsion. At the electron microscopic level, mitochondrial structure was preversed in both normal and injured myocytes of hearts perfused with PFC. We conclude that early signs of anaerobic metabolism are retarded by perfusion with PFC emulsions and that ventricular contractile performance is maintained at approximately one-half coronary perfusate flow in the PFC hearts. The mechanism whereby coronary flow is regulated downward in the PFC perfused hearts remains unanswered.