Fig. 3. Reduced cell proliferation rates in Fgf9^-/- cecal mesenchyme and epithelium. (A,B) H&E stained paraffin sections from E12.5 wild-type (A) and Fgf9^-/- (B) cecum. The amount of mesenchyme (M) in Fgf9^-/- cecal tissue is reduced compared with in wild-type tissue. The insets show a low-power view of the entire cecal section; the boxed region indicates the enlarged area shown. (C,D) BrdU labeling of adjacent cecal sections demonstrating reduced cell proliferation in both the mesenchyme and epithelium (arrow) in Fgf9^-/- (D) tissue compared with in wild-type tissue (C). Dashed line indicates the border of mesenchyme and epithelium; the solid line indicates the apical cap of the cecal epithelium. (E) Quantification of percentage of BrdU-positive nuclei showing significantly decreased cell proliferation in both cecal mesenchyme (^*P<0.001) and epithelium (^**P<0.01) in Fgf9^-/- tissue.