Quantitative changes in myocardial nucleic acids and protein during normothermic and hypothermic pulsatile perfusion with bloodless fluid

Pulsatile perfusion of rabbit hearts with bloodless fluid was performed for 2 to 6 h at normothermic and hypothermic temperatures. All perfused hearts became edematous with the maximum gain in weight occurring at 37°C and the minimum at 5 to 15°C perfusion. Concomitantly, the dry weight fraction of hearts decreased, with the minimum decrease noted at 15°C and the maximum at 37°C perfusion temperature. The DNA content of perfused hearts declined, with the sharpest drop registered at 2-h perfusion and the maximum retention of DNA observed at 25°C. Protein content of myocardium in perfused hearts decreased with the minimum loss observed during 15°C perfusion. In contrast to DNA and protein, the RNA levels were essentially unchanged. It is concluded the pulsatile perfusion within a 15 to 25° temperature range insures maximum retention of myocardial dry weight fraction, DNA, protein and RNA.