Generation and characterization of SS-Selp^−/−mice. (A) Selp^−/− mice were bred to Townes SS mice to generate SS-Selp^−/− mice. Refer to supplemental Figure 1 for the breeding strategy. (B) Genomic PCR gel image showing the presence or absence of different alleles in C57BL/6 (WT) mice, Townes AS (AS) mice, Townes SS (SS) mice, Selp^−/− mice, and SS-Selp^−/− mice. Human WT β-globin (WT β^A), mouse β-globin, mouse α-globin, and mouse WT P-selectin alleles were absent in SS-Selp^−/− mice, but human β^S, human α-globin, and mouse mutant P-selectin (P-selectin^−/−) alleles were present in SS-Selp^−/− mice. (C) RT2qPCR analysis revealed a significant reduction in the mRNA levels of P-selectin in the aortas of SS-Selp^−/− mice compared with SS mice. Data are mean relative mRNA expression ± standard deviation (SD). (D) Western blot analysis of CD62P protein levels in platelets isolated from SS and SS-Selp^−/− mice. P-selectin (135 kDa) was expressed in platelets of SS mice but was absent in platelets of SS-Selp^−/− mice. Actin (37 kDa) was used as a loading control. Recombinant mouse P-selectin–Fc fusion protein (RP; 235 kDa; R&D Systems) was used as a positive control. Data in panels C-D are representative of 3 female SS mice and 3 female SS-Selp^−/− mice. Representative IHC images showing sinusoidal congestion by H&E staining (E) and fibrosis and collagen deposition by Sirius Red staining (F) in the liver sections of SS and SS-Selp^−/− mice. Original magnification ×40. (G) Percentage of sinusoidal congestion based on H&E staining. (H) Quantification of liver fibrosis as the percentage of the area positive for Sirius Red staining. Data in panels G-H are mean ± SE based on 3 male SS mice and 3 male SS-Selp^−/− mice. *P < .05.