Hypothermic Machine Perfusion Ameliorates Ischemia-Reperfusion Injury in Rat Lungs From Non-Heart-Beating Donors

Background. The use of non-heart-beating donors (NHBD) has come into practice to resolve the shortage of donor lungs. This study investigated whether hypothermic machine perfusion (HMP) can improve the quality of NHBD lungs. Methods. An uncontrolled NHBD model was achieved in male Lewis rats. Ninety minutes after cardiac arrest, HMP was performed for 60 min at 6 degrees C to 10 degrees C. The first study investigated the physiological lung functions during HMP and the lung tissue energy levels before and after HMP. The second study divided the rats into three groups (n = 6 each): no ischemia group; 90-min warm ischemia + 60-min HMP + 120-min static cold storage (SCS) (HMP group); and 90-min warm ischemia + 180-min SCS group. All lungs were reperfused for 60 min at 37 degrees C. Lung functions were evaluated at given timings throughout the experiments. Oxidative damage during reperfusion was evaluated immunohistochemically with a monoclonal antibody against 8-hydroxy-2'-deoxyguanosine. Results. The first study revealed that lung functions were stable during HMP. Lung tissue energy levels decreased during warm ischemia but were significantly increased by HMP (P < 0.05). The second study confirmed that HMP significantly decreased pulmonary vascular resistance, increased pulmonary compliance, and improved pulmonary oxygenation. The ratio of 8-hydroxy-2'-deoxyguanosine positive cells to total cells significantly increased in the SCS group (P < 0.01). Conclusions. Short-term HMP improved lung tissue energy levels that decreased during warm ischemia and ameliorated ischemia-reperfusion injury with decreased production of reactive oxygen species.