Sepsis is an unusual systemic reaction with high mortality and secondary septic liver injury is proposed to be the major cause of mortality. Extracorporeal membrane oxygenation (ECMO) can enhance terminal organ perfusion by elevating circulatory support which is used in severe sepsis patients. However, the interaction of blood components with the biomaterials of the extracorporeal membrane elicits a systemic inflammatory response. Besides, inflammation and apoptosis are the main mediators in the pathophysiology of septic liver injury. Therefore, we investigated the protective effect of Deoxyribonuclease I (DNase I) against septic liver injury supported by ECMO in rats. Sepsis was induced by lipopolysaccharide (LPS) and 24 hours after the administration, the rats were treated with ECMO. Then blood samples and liver tissues were collected. DNase I significantly attenuated the level of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and significantly decreased hepatic levels of NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome, myeloperoxidase (MPO), downstream inflammatory factor interleukin-1 β (IL-1 β ) and interleukin-18 (IL-18), and improved neutrophil infiltration. Additionally, DNase I significantly reduced the expression of apoptosis key protein and terminal-deoxynucleotidyl transferase-mediated nick end labeling (TUNEL)-labeled apoptotic hepatocytes. In summary, our findings demonstrated that DNase I alleviates liver injury in ECMO-supported septic rats by reducing the inflammatory and apoptotic responses.Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the ASAIO.