Fig 3. No change in bone formation, but an increase in bone resorption, in Lmna^HSA-cko mice.

(A) Serum Ocn levels in 3-mo Lmna^f/f and Lmna^HSA-cko mice. The serum Ocn levels were measured by ELISAs. The values shown are means ± SD from four males per genotype. (B) Representative images of histologic sections showing calcein labeling of endocortical bone in femur mid-diaphysis of Lmna^HSA-cko and Lmna^f/f mice. (C-E) Ec.MAR (C), MS/BS (D), and Ec.BFR (E) are presented. The values shown are means ± SD from four males per genotype. (F) ELISA analysis of serum PYD levels. The values presented are means ± SD (n = 3). *P < 0.05, significant difference. (G) Colorimetric analysis of serum calcium levels. The values presented are means ± SD (n = 3). **P < 0.01, significant difference. (H) TRAP staining analysis of femur sections from 1-mo and 3-mo Lmna^f/f and Lmna^HSA-cko mice. Scale bar, 100 μm. (I) Quantification analysis as means ± SD (n = 5 femur samples for each group). *P < 0.05, ***P < 0.001, significant difference. (J) TRAP staining analysis of cultured OCs derived from 3-mo Lmna^f/f and Lmna^HSA-cko mice. Cells were treated with 100 ng/ml RANKL for 7 days. (K) Quantitative data of TRAP⁺ MNCs (more than three nuclei) per randomly selected visual field. Scale bar, 100 μm. Data shown are means ± SD from five different cultures. **P < 0.01. The underlying data for this figure can be found in S1 Data. BFR, bone formation rate; BS, bone surface; cko, conditional knockout; Ec.BFR, endocortical bone formation rate; Ec.MAR, endocortical mineral apposition rate; HSA, human alpha-skeletal actin; Lmna, lamin A/C gene; Lmna^f/f, floxed Lmna mice; Lmna^HSA-cko, skeletal muscle–specific Lmna-cko mice; MAR, mineral apposition rate; MNC, multinucleated cell; mo, months old; MS, mineral surface; NF-κB, nuclear factor kappa-light-chain-enhancer of activated B cells; OC, osteoclast; Ocn, osteocalcin; PYD, pyridinoline; RANKL, receptor activator of NF-κB ligand; TRAP, tartrate-resistant acid phosphatase.