In vivo administration of strontium increases bone formation. (A) Serum blood was obtained from untreated and treated for 4, 6, 8, and 12 weeks with Sr mice and the concentration of osteocalcin was measured by ELISA. Data are mean (± SEM; n = 8 per group). * P < .05 and ** P < .01. (B) Tibias from mice treated with Sr for 8 weeks were subjected to micro-CT analysis and were compared with ones from untreated age-matched littermates. Representative images of 3D micro-CT reconstruction (i) and 2D microCT scan (ii). (C) Hematoxylin and eosin staining in paraffin-embedded sections of decalcified tibias, vertical (i) and parallel (ii) to the long axis of the tibia sections. Magnifications, ×100. (D) N-cadherin staining in femur sections from mice treated with Sr for 8 weeks (right) and untreated mice (left). Arrows indicate N-cadherin⁺ osteoblasts. Magnifications, ×200. (E) Osteoblasts were obtained from tibias and femurs of mice treated with Sr for 8 weeks or untreated mice, and the mRNA expression levels of N-cadherin were determined by real-time RT-PCR. The results are reported as fold change in gene expression relative to untreated controls after being normalized to GAPDH (ΔΔC_T method), and columns represent the mean value (± SEM) of 2 different experiments (4 mice per group).