Figure 4

LRP6 deletion in nestin⁺ MSCs results in dramatic decreased osteoblast numbers. (a–h) Bone histomorphometric analysis of the primary spongiosa area (a–d) and secondary spongiosa area (e–h) of femur from 3-month-old male Lrp6^+/+ , Lrp6^+/− and Lrp6^−/− mice. Number of osteoblasts per bone perimeter (N.Ob/B.Pm) (a and e), osteoblast surface per bone surface (Ob.S/BS) (b and f), number of osteoclasts per bone perimeter (N.Oc/B.Pm) (c and g) and osteoclast surface per bone surface (Oc.S/BS) (d and h). A total of three femur sections from each mouse, and six mice per treatment group were analyzed. *P<0.05, **P<0.01, ***P<0.001, vs. Lrp6^+/+ group. (i–l) Representative TRAP staining and quantitative analysis of the primary spongiosa area (i and j) and secondary spongiosa area (k and l) of trabecular bone sections from distal femur. Arrows, TRAP⁺ cells. Scale bars=100 µm. Number of TRAP-positive cells per mm² tissue area (N.TRAP⁺ cells/T.Ar). A total of three femur sections from each mouse, and six mice per treatment group were analyzed. *P<0.05, **P<0.01, ***P<0.001, vs. Lrp6^+/+ group. (m and n) Serum levels of Ocn (m) and CTX-I (n) in wild-type Lrp6^+/+ , Lrp6^+/− and Lrp6^−/− mice. n=4; *P<0.05. Data are presented as mean±s.e.m. CTX-I, c-terminal telopeptide of type-1 collagen; Ocn, osteocalcin.