Figure 5.

Proliferation of osteoblastic cells, apoptosis of osteoblasts and osteocytes, and bone resorption in the femurs of male Sp7^fl/fl and Sp7^{fl/fl;Col1a1−Cre} mice (A–E) Proliferation of osteoblastic cells in trabecular bone of Sp7^fl/fl and Sp7^{fl/fl;Col1a1−Cre} mice at 3 weeks of age. A and B, H-E staining. C and D, BrdU staining, which was counterstained with hematoxylin. E, Frequency of BrdU-positive cells in the region shown in C′ and D’. n = 3 (Sp7^fl/fl mice) and n = 3 (Sp7^{fl/fl;Col1a1−Cre} mice). (F–R) Apoptosis of osteoblasts and osteocytes in Sp7^fl/fl and Sp7^{fl/fl;Col1a1−Cre} mice at 10 weeks of age. F–J, H-E (F, G), and TUNEL (H, I) staining of metaphyseal cortical bone and the frequency of TUNEL-positive osteoblasts in the endosteum (J). K–O, H-E (K, L), and TUNEL (M, N) staining of cortical bone at the mid-diaphysis and the frequency of TUNEL-positive lacunae in cortical bone (O). P–R, TUNEL staining of trabecular bone (P, Q) and the frequency of TUNEL-positive lacunae in trabecular bone (R). Arrows show TUNEL-positive lacunae and arrowheads show TUNEL-negative osteocytes in M′, N′, P′, and Q’. The number of TUNEL-positive lacunae and TUNEL-negative osteocytes were counted, and the frequency of TUNEL-positive lacunae was calculated. TUNEL stained sections were counterstained with methyl green. (S–Z) Safranin O staining of trabecular bone (S, T) and TRAP staining of trabecular bone (V, W) and cortical bone (Y, Z) in Sp7^fl/fl and Sp7^{fl/fl;Col1a1−Cre} mice at 10 weeks of age. The ratio of the safranin O-positive area to the total bone area is shown in U, and the number of TRAP-positive cells in the trabecular and cortical bones is shown in X and Z″, respectively. n = 4 (Sp7^fl/fl) and n = 5 (Sp7^{fl/fl;Col1a1−Cre}). Boxed regions in A–D, F, G, H, I, K, L, M, N, P, Q, S, T, V, W, Y and Z were magnified in A’ –D′, F′, G′, H′, I′, K′, L′, M′, N′, P′, Q′, S′, T′, V′, W′, Y'and Z′, respectively. Scale bars: 200 μm (A–D, F, G, H, I, K, L, M, N, P, Q, S, T, V, W, Y and Z), 20 μm (A′–D′, F′, G′, H′, I′, K′, L′, M′, N′, P′, Q′, S′, T′, V′, W′, Y'and Z′). (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)