When does the lung die? Time course of high energy phosphate depletion and relationship to lung viability after "death".

The shortage of lung donors for clinical transplantation could be significantly alleviated if lungs could be retrieved from cadavers hours after death. However, the time course of loss of lung viability after circulatory arrest and organism death remains unclear. To determine postmortem adenine nucleotide tissue levels in the lung and their relationship to lung viability, Sprague-Dawley rats were sacrificed and then ventilated with 100% oxygen (n = 50, O2) or 100% nitrogen (n = 40, N2) or left nonventilated (n = 50). Lungs from control rats (n = 20) were retrieved immediately after sacrifice. Lungs in the three study groups were retrieved at successive intervals postmortem. Adenine nucleotides (ATP, ADP, and AMP) and hypoxanthine and xanthine metabolites of adenosine were extracted from lung tissue and measured using high-performance liquid chromatography. Pulmonary parenchymal cell viability was quantified by pulmonary artery infusion of trypan blue vital dye in the contralateral lung of each animal. By 4 hr postmortem, viability was 85 +/- 1% in the O2-ventilated cadaver rat lungs, significantly higher than in the N2-ventilated (43 +/- 8%) and in the nonventilated (48 +/- 4%) lungs, where the percentage of viable cells was similar. All of the groups showed a time-dependent decrement in ATP levels and total adenine nucleotide (TAN) levels after death, but this was markedly attenuated in O2-ventilated cadaveric rat lung.(ABSTRACT TRUNCATED AT 250 WORDS)