Anterior semicircular canal dysmorphism in Casp3-/-mice. (A) Whole mount vestibular epithelia of Casp3-/-, Casp3+/-, and Casp3+/+ mice. anterior- and lateral crista, and utricle were smaller, whereas the posterior crista and saccule were normal in size in Casp3-/- mice. All vestibular sensory epithelia were normal in size and shape in Casp3+/- and Casp3+/+ mice. (B, C, D, E) Comparison of morphologic changes in utricle, anterior crista, and lateral crista. Examples of severe dysmorphisms in Casp3-/- mice are shown in C and D, compared to normal utricle, anterior crista, and lateral crista in Casp3+/- mice in B. (C) Anterior- and lateral crista was fused in some Casp3-/- mice. (D) Significantly smaller size in anterior crista (white box) in Casp3-/- mice. Although hair cell number in the anterior crista is significantly reduced, the morphology of the stereocilia of the cells seem normal in shape and size (E). A magnified image of the anterior crista (white box in D) is shown in E. (F) Hair cell numbers in the vestibular sensory epithelia. Average hair cell numbers ± S.D. of Casp3+/+ (n = 3), Casp3+/- (n = 5), and Casp3-/- (n = 7) were compared. Black, Casp3+/+. Gray, Casp3+/-. White, Casp3-/-. Statistically significant differences (ANOVA, P < 0.05) are marked with *. U, utricle. ant, anterior crista. lat, lateral crista. post, posterior crista. Scale bar, 100 μm, except for in panel E (= 10 μ m).