Studies of rat lung viability and adenine nucleotide metabolism after death

Background. Prior studies from our laboratory have supported the use of cadaveric lungs for transplantation. In this study we investigated different preservation strategies for lungs retrieved from cadavers 4 hours after circulatory arrest. Methods. Seventy-two Sprague-Dawley rats were sacrificed and then ventilated with 100% oxygen for 4 hours. The lungs were then flushed with modified Euro-Collins, University of Wisconsin, or Carolina rinse solution, either alone, with prostaglandin E(1), or with prostaglandin E(1) plus the free radical scavenger dimethylthiourea. After an additional 4-hour cold storage, the left lung was flushed with trypan blue solution to quantify cell viability, whereas the right lung was used to determine wet-to-dry weight ratios and to measure the levels of the adenine nucleotides adenosine triphosphate, adenosine diphosphate, and adenosine monophosphate by highperformance liquid chromatography. Results. Viability was consistently better in the lungs flushed with Carolina rinse solution; these differences were statistically significant compared with those in the corresponding modified Euro-Collins subgroups (p < 0.005). The addition of prostaglandin E(1) to all three preservation solutions improved the total adenine nucleotide levels; this increase was statistically significant for the modified Euro-Collins subgroup (p < 0.005). The total adenine nucleotide levels for the University of Wisconsin subgroups were higher than those for the corresponding modified Euro-Collins subgroups. The highest total adenine nucleotide levels were obtained in lungs flushed with Carolina rinse plus prostaglandin E(1). Wet-to-dry weight ratios were always significantly lower in the lungs preserved with University of Wisconsin solution (p < 0.05), with a value similar to that of fresh tissue. Conclusions. The characteristics of the solution used to flush and to store rat cadaveric lungs have an impact on lung viability and adenine nucleotide metabolism. The ideal preservation strategy may allow for lung retrieval from cadavers for safe transplantation.