Fig. 2: BMP9 reduces age-related bone loss and improves bone microarchitecture.

A Six-month-old and twenty-month-old mice were injected with AAV-BMP9 or AAV-CON, respectively. Twelve weeks after injection, mice were euthanized for subsequent experiments. B Representative images derived from micro-CT analysis, including 2D image construction of distal femur, 3D image reconstruction of trabecular bone of distal femur, and 3D image reconstruction of the femoral midshaft corticoid bone. C Quantitative analysis of the vBMD of trabecular by micro-CT. D–G Microarchitecture analysis of trabecular bone by micro-CT: Trabecular BV/TV (D), Tb.Th (E), Tb.Sp (F) and SMI (G). H Quantitative analysis of the vBMD of cortical by micro-CT. I, J Quantitative analysis of the BV/TV (I) and Ct.Th (J) of corticoid bone by micro-CT. K Representative images of HE-stained decalcified vertebrae sections (n = 6) (Scale bar, 500 μm). For micro-CT analysis: n = 9 for 6 M + AAV-CON group; n = 7 for 6 M + AAV-BMP9 group; n = 9 for 20 M + AAV-CON group; n = 8 for 20 M + AAV-BMP9 group. Data presented as mean ± SD. One-way ANOVA was used for comparison among multiple groups. AAV-CON = empty adeno-associated virus; AAV-BMP9 = BMP9 overexpressing adeno-associated virus; BV/TV = percentage of bone volume; Tb.Th = trabecular thickness, Tb.Sp = trabecular separation, SMI = structure model index, Ct.Th = cortical thickness. *P < 0.05; **P < 0.01; ***P < 0.001. Ns, no significance.