Immunostaining of the cell adhesion marker β-catenin in the placentas of WT and Bcrp-null pregnant mice treated with CdCl₂. Pregnant mice were treated with a single injection of saline (5 ml/kg, IP) or CdCl₂ (5 mg/kg, IP) on GD9. Placentas were collected on GD17. Placentas preserved in 10% zinc formalin were made into paraffin blocks following routine processing. Sections (5 µm) of placentas from dams treated with saline or CdCl₂ (5 mg/kg) were stained for (A) β-catenin (1:100) using immunohistochemistry. Negative control slides omitted incubation with primary antibody. Magnification was set at ×40, and the scale bar = 50 µm. B, ImageJ Fiji package was used to semiquantify the intensity of β-catenin DAB staining. Individual data are presented in addition to mean ± SE (n = 5–7 dams). Two-way ANOVA. *p ≤ .05, compared with saline-treated mice of the same genotype. ^†p ≤ .05, compared with Cd-treated WT mice.