Comparative evaluation of single-artery cannulation with passive venous drainage versus traditional dual-cannula ex vivo lung perfusion in a rat model

Background: Ex vivo lung perfusion (EVLP) has emerged as a critical technique for lung preservation and evaluation prior to transplantation. While conventional rat EVLP systems utilize closed-loop dual cannulation of pulmonary artery (PA) and vein, the effect of the simplified model using single PA cannulation with passive venous drainage is unknown. Methods: We developed two EVLP models in rats: a semi-closed circuit with PA-only cannulation and left atrial incision for passive venous drainage (SC-EVLP), and a closed circuit employing both arterial and venous cannulation (C-EVLP). Donor lungs were perfused for a defined duration and subsequently orthotopically transplanted. We evaluated pulmonary function parameters, histopathological injury scores, inflammatory cytokine levels, and apoptotic marker expression at the end of perfusion and posttransplantation. Results: Compared to the conventional EVLP, the SC-EVLP group exhibited significantly lower PA pressure and improved dynamic lung compliance throughout perfusion. Although the levels of tumor necrosis factor-α in the perfusate were higher in the SC-EVLP group, other cytokine levels in the perfusate and bronchoalveolar lavage fluid exhibited no significant differences. Pulmonary edema was reduced in the SC-EVLP group, as indicated by a lower lung wet-to-dry ratio. After transplantation, lungs from the SC-EVLP group exhibited lower histological injury scores, reduced apoptosis, and decreased serum cytokine levels, suggesting attenuated inflammation and tissue damage. Conclusions: In a rat model, single PA cannulation with passive venous drainage reduced pulmonary edema during EVLP and reduced lung injury and systemic inflammation after transplantation.