ResultsRecipient Abx pretreatment attenuates, but adjunctive fecal microbiota transfer recreates, hepatic IRI in mouse allogeneic OLT. We first aimed to determine the influence of Abx treatment on IRI severity in a clinically relevant allogeneic mouse OLT model (BALB/c> C57BL/6) with ex vivo cold storage (4°C for 18 hours), which mimics marginal human liver grafts. Mouse OLT recipients pretreated for 10 days (14, 15) with oral Abx (amoxicillin, 50 mg/mL) showed decreased serum aspartate aminotransferase (sAST) levels (OLT = 7047 ± 1332 vs. OLT + Abx = 3609 ± 447 IU/L, P = 0.0317; Figure 1A); attenuated sinusoidal congestion, edema/vacuolization and hepatocellular necrosis ( Figure 1B); decreased Suzuki's histological grading of IRI (OLT = 6.8 ± 0.6 vs. OLT + Abx = 3.6 ± 0.5, P