Immunohistochemical staining of mast cells. Toluidine blue staining (A) and safranin/alcian blue staining (B) of mast cells (indicated by arrows in red) in the back skin from WT and AKO mice at 12 weeks of age (original magnification ×200). Scale bar represents 50 μm. Data are representative of 3 independent experiments. (C) Quantitative analysis of (A) *P < .05, n = 9. (D) Quantitative analysis of peritoneal mast cells by Toluidine blue staining. *P < .05, n = 10. Data are representative of 3 independent experiments.