Fig 1.
a) Timeline of the study: the mice were ovariectomized (OVX) at the age of 12 weeks and an initial scan was taken; 9 weeks after the surgery a check scan was done to confirm the bone loss; implant was inserted into the vertebra at the age of 21 weeks and a scan was performed right after implantation, followed by weekly scans for 6 weeks. The check scan and the scan at week0 were acquired one day apart. b) Schematic illustration of the implanted vertebra: the implant was inserted into CV6 along the left right axis. Image modified with permission from [1]. c) Image processing steps: the original grey-scale micro-CT scan (left) was segmented from the background and the three-dimensional reconstruction of the bone (light grey) with the implant (black) was produced (middle); different regions close to and far from the implant where bone (re)modeling was monitored were defined including periosteal and endocortical surfaces as well as trabecular bone (right).
Fig 2.
Three-dimensional visualization of the bone formation and bone resorption sites over time in cortical (top) and trabecular (bottom) bone for a representative ovariectomized (OVX) and sham-operated (SHM) mouse.
Table 1.
Changes in bone architecture after estrogen removal.
Fig 3.
Bone (re)modeling rates for ovariectomized (OVX) and sham-ovariectomized (SHM) mice in peri-implant region of periosteal surface (a, d and g), endocortical surface (b, e and h), and trabecular bone (c, f and i).
* denotes a significant difference (p < 0.05) between groups within the same time interval. Significant differences between first and last time interval are marked by # in Table 2. Data reported as mean ± standard error.
Table 2.
Bone (re)modeling post implantation close to the implant.
Fig 4.
Bone (re)modeling rates for ovariectomized (OVX) and sham-ovariectomized (SHM) mice in the distant region of periosteal surface (a, d and g), endocortical surface (b, e and h), and trabecular bone (c, f and i).
* denotes a significant difference (p < 0.05) between groups within the same time interval. Significant differences between first and last time interval are marked by # in Table 3. Data reported as mean ± standard error.
Table 3.
Bone (re)modeling post implantation far from the implant.
Fig 5.
Changes in the length of the implanted vertebra monitored for the entire experiment (including OVX/SHM surgery and implant insertion).
On the right, a three-dimensional visualization of bone remodeling in the whole vertebra is reported, with the lengthening corresponding to high bone formation localized in the growth plates (which were excluded from the analysis of bone (re)modeling) (a). Time evolution of cortical thickness (Ct.Th) and bone volume fraction (BV/TV) in the peri-implant (b, d) and distant bone (c, e) for ovariectomized (OVX) and sham-ovariectomized (SHM) mice following implantation. Differences in Ct.Th and BV/TV between the first and the last time point in the peri-implant and distant region are also shown in percentage changes (f). * denotes a significant difference (p < 0.05) between groups. Significant differences between first and last time point are marked by # in Table 4. Data reported as mean ± standard error.
Table 4.
Changes in bone architecture following implant placement.