Characterization of the prothrombotic phenotype of AT-deficient and AT-infused mice. Mice were treated with control siRNA and AT siRNA, followed by infusion of saline, AT-WT, AT-4Mut, or AT-R425del at 24 and 48 hours of siRNA treatment. Mice were euthanized after 72 hours of siRNA treatment and perfused with PBS. (A) Perfused liver cryosections were fixed, permeabilized, and incubated with anti-CD41 (rat; platelet marker) and anti-CD31 (goat) antibodies followed by Alexa Fluor 562–conjugated and anti-rat Alexa Fluor 488–conjugated anti-goat antibodies. DAPI was used to stain the nucleus. The arrows indicate platelet-rich thrombus. Inset boxes from each group are magnified. Scale bar, 50 μm. (B) Relative MFI of CD-41 staining is presented. All data are presented as mean ± SEM. n ≥ 3. Statistical analysis was performed using Graph Pad Prism 10. P values are determined by 1-way ANOVA, followed by Bonferroni multiple comparison test. ∗∗P < .01; ∗∗∗∗P ≤ .0001. ns, not significant.