Fig. 1

The increase of HDAC9 was associated with bone and fat imbalance in bone aging. a Micro-CT analyses of bone mass of trabecular and cortical bone thickness in the femora of 2-month-old (young) and 16-month-old (aged) mice. Bone mineral density (BMD), trabecular bone volume (BV/TV), and cortical bone thickness (Ct.Th) were performed. Scale bar = 1 mm. b–d Immunofluorescent staining of OCN (b), PPAR-γ (c), and TRAP (d) was performed in the bone marrow from young and aged mice, and the positive signals were quantitatively analyzed. Scale bar = 50 μm. e Expressions of the senescence-related proteins, p53 and p-p53, in the bone marrow from young and aged mice were examined by western blotting. f Expressions of the senescence-related proteins, p53 and p-p53, in BMMSCs from young and aged mice were examined by western blotting. g Alizarin Red staining was performed, and quantification of mineralized nodules was analyzed in young and aged BMMSCs. h Oil Red O staining was performed, and quantification of lipid droplet positive ratio areas was analyzed in young and aged BMMSCs. Scale bars = 100 μm. i, j Expression of HDAC9 (i) and acetylation sites of H3K, including H3K9, H3K18, and H4K16 (j), were examined by western blotting. The data are presented as the means ± SD of each independent experiment performed in triplicate. *P < 0.05, **P < 0.01, ***P < 0.001, unpaired two-tailed Student’s t test