Although lung transplantation has experienced great development in the past decades, the survival rate remains low, and lung ischaemia–reperfusion injury during transplantation is a major cause of primary graft dysfunction, which causes early morbidity and death after lung transplantation. Extracorporeal membrane oxygenation (ECMO) has been increasingly used as intraoperative support during lung transplantation. However, the clinical outcomes of intraoperative ECMO in lung transplantation remain controversial. Here, we established veno-venous ECMO (VV ECMO) in a lung ischaemia–reperfusion rat model to investigate its impact on lung injury.

Eighteen rats were allocated to Sham, ischemia–reperfusion (IR) and IR-ECMO group. Using left pulmonary hilum ischaemia for 1 h, VV ECMO was established during reperfusion for 2 h. Lung tissue, blood sample and bronchoalveolar lavage fluid were collected for further evaluation using haematoxylin and eosin staining, immunohistochemistry, quantitative polymerase chain reaction, bicinchoninic acid assay and enzyme-linked immunosorbent assay.

VV ECMO aggravates lung ischaemia–reperfusion injury; the pathological injury is more severe in the IR-ECMO group, and biomarkers of lung injury, including soluble receptor for advanced glycation end products and surfactant protein-D, also significantly increased. There are more neutrophil and macrophage infiltrations in the IR-ECMO group as well. We also observed higher expression of inflammatory factors, including interleukin-6, interleukin-1β and tumour necrosis factor-α in the lung tissues and serum.

This study found VV ECMO significantly exacerbates lung ischaemia–reperfusion injury and pulmonary inflammatory response in a rat model after lung ischaemia–reperfusion.