Alb-TRECK/SCID mice develop fulminant hepatic failure after diphtheria toxin injection. (A) Serum aspartate transaminase (AST) activity levels over time after diphtheria toxin (DT) injection during the first 96 hours. DT doses of 0.5, 1, 1.5, 2, and 5 μg/kg were injected into 8 week-old Alb-TRECK/SCID mice, and serum AST activity was determined every 24 hours. Results are means ± standard error of the mean (n = 5/group). (B) Macroscopic views (left panels) and histology (hematoxylin and eosin (H&E) staining, right three panels) of mouse livers without and with administration of DT after 48 hours. DT dose: 1.5 μg/kg, serum AST activity of normal liver: 30 IU/L; serum AST activity of DT-treated liver: 12,000 IU/L. CV, central vein; PV, portal vein. Scale bars = 100 μm. (C) Kaplan–Meier survival curves of Alb-TRECK/SCID mice with different AST activities within 3 days after DT injection (numbers of mice in each group are indicated in the figure). *P < 0.05, **P < 0.01, ***P < 0.001. NS, not significant.