Comparison of Celsior and Perfadex lung preservation solutions in rat lungs subjected to 6 and 12 hours of ischemia using an ex-vivo lung perfusion system

Abstract

Objective: This study evaluated the performance of lungs that were preserved with different solutions (Celsior, Perfadex or saline) in an ex vivo rat lung perfusion system.

Methods: Sixty Wistar rats were anesthetized, anticoagulated and randomized into three groups (n = 20). The rats were subjected to antegrade perfusion via the pulmonary artery with Perfadex, Celsior, or saline, followed by 6 or 12 hours of ischemia (4ºC, n = 10 in each group). Respiratory mechanics, gas exchange and hemodynamics were measured at 10-minute intervals during the reperfusion of heart-lung blocks in an ex vivo system (IL2-Isolated Perfused Rat or Guinea Pig Lung System, Harvard Apparatus, Holliston, Massachusetts, USA; Hugo Sachs Elektronik, Germany) for 60 minutes. The lungs were prepared for histopathology and evaluated for edema following reperfusion. Group comparisons were performed using ANOVA and the Kruskal-Wallis test with a 5% level of significance.

Results: Gas exchange was not significantly different between lungs perfused with either Perfadex or Celsior at the same ischemic times, but it was very low in lungs that were preserved with saline. Airway resistance was greater in the lungs that were preserved for 12 hours. Celsior lungs that were preserved for 6 and 12 hours exhibited lower airway resistance (p = 0.01) compared to Perfadex lungs. Pulmonary artery pressure was not different between the groups, and no significant differences in histopathology and apoptosis were observed between the groups.

Conclusions: Lungs that were preserved with Celsior or Perfadex exhibited similar gas exchange and histopathological findings. Airway resistance was slightly lower in the Celsior-preserved lungs compared with the Perfadex-preserved lungs.

Figure 1

Mean relative oxygenation capacity (ROC) of rat lungs subjected to ischemia and reperfusion for 60 minutes, illustrating no significant differences between Celsior- and Perfadex-perfused lungs at either ischemic time. The lungs subjected to 6 hours of cold ischemia exhibited higher ROCs than the 12-hour ischemic lungs, but this difference was significant only for the lungs preserved with saline (p = 0.001).

Figure 2

Mean lung compliance of rat lungs submitted to ischemia and reperfusion for 60 minutes, illustrating no significant differences between lungs preserved with Celsior and Perfadex. Lungs subjected to ischemia for 6 hours performed better than those subjected to 12 hours of ischemia.

Figure 3

Airway resistance of rat lungs subjected to ischemia and reperfusion for 60 minutes. The Celsior lungs exhibited the lowest airway resistance for both ischemic times. The airway resistance was lower in lungs submitted to 6 hours of ischemia compared with those submitted to 12 hours of ischemia.

Figure 4

Histopathology of lungs preserved for 6 hours with Perfadex. Sites of mild alveolar edema can be observed (white asterisks). Similar findings were observed in Celsior-preserved lungs (hematoxylin-eosin, 200X magnification).

Figure 5

Pneumocyte with a tendency for peripheral chromatin aggregation that is compatible with ongoing apoptosis (red arrows) (transmission electron microscopy, 8900X magnification).

Figure 6

Immunofluorescence microscopy (TUNEL) imaging for cell death analysis. Fluorescent-labeled cells (green) correspond to tissue death by apoptosis.