Background: Liver transplantation from donors after cardiac death (DCD) has been a routine treatment for end-stage liver diseases. Normothermic machine perfusion (NMP) could be beneficial for the function recovery of DCD livers. The mechanism of NMP is still unclear. The purpose of the study was to investigate the molecular changes and the underlying mechanism of liver recovery with NMP.

Methods: The SD rat livers were subjected to 30 warm ischemia after cardiac attest and thereafter stored for 8h under cold static preservation, which was harvested and regarded as Group cold static (Group CS，n=6). In experimental groups, livers received an ex vivo dual NMP without an autophagy inhibitor (Group NMP，n=6), 3-methyladenine (3-MA), or with (Group 3-MA，n=6) in the perfusate for 2h. Perfusates were harvested to detect hepatic enzyme activity and liver samples were harvested to detect the expression of autophagy-related proteins Atg7, Beclin-1, LC3, and liver function. Comparative proteomic analysis was performed using an integrated approach involving LC-MS/MS analysis and Tandem Mass Tag labeling.

Result: Compared with Group CS, lower hepatic injury of Group NMP was characterized by a lower change of liver enzymes and a better histological evaluation. Proteomics indicated that a total of 294 differentially expressed proteins were identified with 196 up-regulated proteins and 98 down-regulated proteins in NMP livers compared with Group CS. There were notable differences in the expression of autophagy-related proteins between Group NMP and Group CS. Additionally, NMP pretreatment increased the ratio of LC3-II/LC3-I, the expression of Beclin-1 and Atg7 based on Western blot than Group CS. The autophagy inhibitor upregulated perfusate aminotransferases and increased the Suzuki score.

Conclusion: NMP can decrease hepatic ischemia-reperfusion injury and may confer better protection against liver damage from DCD. Autophagy may participate in liver functional recovery from DCD with NMP, indicating that liver autophagy might be a key therapeutic target for rehabilitating the function of DCD.