Defibrotide sodium is a complex blend of single-stranded polydeoxyribonucleotides, exhibiting liver protective, anti-inflammatory, antithrombotic, profibrinolytic, and anti-ischemic properties. It is utilized in research related to sinusoidal obstruction syndrome (SOS)/veno-occlusive disease (VOD) [1].

Defibrotide sodium exerts anti-inflammatory effects by agonizing adenosine A1 and A2 receptors, reducing the expression of intracellular adhesion molecule-1, and inhibiting the release of inflammatory mediators [1]. It inhibits platelet aggregation by enhancing prostaglandin I2 and E2 production, stimulates fibrinolysis by increasing tPA activity and inhibiting plasminogen activator inhibitor type 1 activity [1], and decreases tissue factor production while increasing tissue factor pathway inhibitor production, thereby reducing extrinsic coagulation cascade activation and fibrin deposition [1]. Additionally, defibrotide sodium protects against endothelial cell damage mediated by tumor necrosis factor α and fludarabine-induced activation and apoptosis [1].

Administration of Defibrotide sodium via intracarotid (i.c.) injection at a dose of 64 mg/kg followed by continuous infusion for 1 hour significantly diminishes the capacity of thrombin (100 μg/kg) to cause cranial thromboembolism in rabbits [2]. Intravenous (i.v.) injection of thrombin (20 μg/kg) in rabbits leads to a reversible buildup of radiolabeled platelets in the thoracic circulation, which is notably mitigated by i.v. administration of defibrotide (64 mg/kg bolus plus 64 mg/kg/h for 1 hour) before the thrombin introduction [2]. In mice, intravenous injection of human thrombin (1250 μg/kg) typically results in death for most animals, an outcome significantly reduced with pretreatment using defibrotide (150-175 mg/kg, i.v.) [2].