Maximum load (p = 0.0043) and Young’s modulus (p = 0.0008) were significantly
enhanced compared to OVX rats. Although the yield load of SHAM rats had higher mean values, the difference failed to reach significance. Whole-body vibration induced improved biomechanical properties in both groups. A significant improvement was observed for the point of change from elastic to plastic deformation (p = 0.0036) consistent with the incidence of the first microcracks (i.e., the yield load). A significant improvement was also observed in Young’s modulus (p = 0.0009), while the maximum load, which primarily depends on cortical bone parameters, showed higher but non-significant changes in mean values. The treated OVX rats reached selleck chemical (S), or even exceeded (y L), the values of the untreated SHAM rats (Table 1, Fig. 3). Fig. 3 Results of the histomorphometry. The p value between treated and untreated animals was calculated using PF-573228 solubility dmso a two-way ANOVA. p values <0.05 were considered significant (*p < 0.05 vs. OVX, #p < 0.05 vs. non vib) Histomorphometry In all measured parameters, SHAM rats demonstrated a significant improvement in the histomorphometric evaluation compared to OVX rats (p < 0.0001 for all parameters). Whole-body vibration induced a significant improvement
of all tested morphologic parameters. Vibration resulted in a significant increase in trabecular bone area (p = 0.0006), number of nodes (p = 0.0089), trabecular width (p = 0.0317), trabecular number (p = 0.0028)
as well as the cortical percentage (p = 0.0032) (Table 1, Fig. 4). Fig. 4 The intravital fluorochrome labeling demonstrated higher Thiamet G bone ABT-263 price apposition after whole-body vibration. a SHAM untreated, b SHAM treated, c OVX untreated, d OVX treated Intravital fluorochrome labeling We observed clear qualitative differences between SHAM and OVX rats (Fig. 4). In the statistical evaluation, the total apposition bandwidth, the apposition bandwidth per day, and the relative apposition bandwidth were analyzed. The apposition bandwidth was significantly increased in OVX compared to SHAM rats (absolute values—p = 0.0009, absolute values per day—p = 0.0026). In OVX animals, the trabecular apposition bands had a stronger green (0–18 days) aspect, while the SHAM groups demonstrated a stronger red (18–24 days) aspect. This observation was confirmed in the semi-quantitative evaluation. The calcein green apposition band (0–18 days) was significantly reduced in SHAM compared to OVX rats (p < 0.0001 for all). The same effect could be observed for the second period (18–24 days), but the apposition bandwidth was still significantly reduced in SHAM compared to OVX rats (absolute values—p = 0.0267, absolute values per day—p = 0.0269, relative values—p = 0.0436). No significant differences were observed in the last period. We therefore concluded that, in SHAM rats, the apposition of new bone formation occurred at a later date compared to apposition in OVX animals (Table 2, Fig. 4).