Fig. 2: Abnormal bone remodeling in Kind2-D1 mice.

a Serum levels of procollagen type 1 amino-terminal propeptide (P1NP), N = 8 male mice per group. *P < 0.05, versus controls, Student’s t test. The results are expressed as the mean ± standard deviation (s.d.). b–e Calcein double labeling. Representative images of 6-month-old male Kind2-D1 and control femoral sections (b). Scale bar, 80 μm. Sections of nondemineralized femurs of 3-month-old female and 6-month-old male Kind2-D1 and control littermates were used for measurements of mineral apposition rate (MAR) (c), mineralizing surface per bone surface (MS/BS) (d), and bone formation rate (BFR) (e). Quantitative MAR, MS/BS, and BFR data for metaphyseal trabecular bones. N = 9 in the 7-month-old control male group; N = 8 in the remaining groups. *P < 0.05, versus controls, Student’s t test. The results are expressed as the mean ± s.d. (f–h) von Kossa staining. Undecalcified sections of femora from 3-month-old female Kind2-D1 mice and control littermates were subjected to von Kossa staining. N = 5 mice per genotype. *P < 0.05, versus controls, Student’s t test. Scale bar, 50 μm. i–k Toluidine blue staining of tibial sections of 2-month-old male Kind2-D1 mice and their control littermates. N = 8 control mice; N = 7 Kind2-D1 mice. *P < 0.05, versus controls, Student’s t test. Red arrowheads indicate osteoblasts located on the cancellous bone surfaces. Scale bar, 40 μm. l, m Immunohistochemical (IHC) staining of tibial sections of 2-month-old male Kind2-D1 mice and their control littermates with an anti-osterix (Osx) antibody. Scale bar, 40 μm. Red arrowheads indicate Osx-positive cells located on the cancellous bone surfaces. Quantitative data of Osx-positive cells located on the cancellous bone surfaces (m). N = 7 control mice; N = 9 Kind2-D1 mice. *P < 0.05, versus controls, Student’s t test. The results are expressed as the mean ± s.d. n Serum level of collagen type I cross-linked C-telopeptide (CTX). N = 6 mice per group. P < 0.05, versus control, Student’s t test. The results are expressed as the mean ± standard deviation (s.d.). o–s Tartrate-resistant acid phosphatase (TRAP) staining. Osteoclast surface/bone surface (Oc.S/BS) (p, q) and osteoclast number/bone perimeter (Oc.N/BPm) (r, s) of primary and secondary cancellous bones were measured using Image-Pro Plus 7.0. Scale bar, 50 μm. N = 8 mice per group. P < 0.05, versus control, Student’s t test. The results are expressed as the mean ± standard deviation (s.d.).