Thrombomodulin improves rat survival after extensive hepatectomy

BackgroundRecombinant human soluble thrombomodulin (rTM) protects against disseminated intravascular coagulopathy by inhibiting coagulation, inflammation, and apoptosis. This study tests the hypothesis that rTM is hepatoprotective after extensive hepatectomy (Hx) and investigates the mechanisms underlying this effect.Materials and methodsExperiment 1: rats (15 per group) were injected with rTM (1.0 or 2.0 mg/kg) or saline just before 95% Hx and their 7-d survival assessed. Experiment 2: rats were assigned to either a treated (2.0 mg/kg rTM just before Hx) or control group (n = 5 per group). Five rats per group were euthanized immediately after surgery, and at 1, 3, 6, 12, and 24 h postoperatively; serum and liver remnant samples were collected for biochemical and histologic analysis, as well as reverse-transcription polymerase chain reaction and Western blotting.ResultsAll saline-injected rats died within 52 h of Hx, whereas injection of 2.0 mg/kg rTM prolonged survival (P = 0.003). rTM increased the number of Ki67-positive cells and reduced the number of terminal deoxynucleotidyl transferase dUTP nick-end labeling-positive cells. The number of myeloperoxidase-positive cells and the expression of high-mobility group box 1 protein did not differ. Reverse-transcription polymerase chain reaction revealed that rTM significantly enhanced protease-activated receptor-1 and sphingosine kinase 1 messenger RNA expression and significantly reduced plasminogen activator inhibitor-1 and Bax messenger RNA expression. Immunohistochemistry and Western blotting demonstrated that protease-activated receptor-1 expression 24 h after Hx was significantly higher in rTM-treated than in control rats.ConclusionsrTM may improve survival after extensive Hx by inhibiting apoptosis and promoting liver regeneration.