Cortical Bone Morphological and Trabecular Bone Microarchitectural Changes in the Mandible and Femoral Neck of Ovariectomized Rats

Abstract

ObjectiveThis study used microcomputed tomography (micro-CT) to evaluate the effects of ovariectomy on the trabecular bone microarchitecture and cortical bone morphology in the femoral neck and mandible of female rats.Materials and MethodsTwelve female Wister rats were divided into two groups: the control and ovariectomized groups. The rats in the ovariectomized group received ovariectomy at 8 weeks of age; all the rats were sacrificed at 20 weeks of age, and their mandibles and femurs were removed and scanned using micro-CT. Four microstructural trabecular bone parameters were measured for the region below the first mandibular molar and the femoral neck region: bone volume fraction (BV/TV), trabecular thickness (TbTh), trabecular separation (TbSp), and trabecular number (TbN). In addition, four cortical bone parameters were measured for the femoral neck region: total cross-sectional area (TtAr), cortical area (CtAr), cortical bone area fraction (CtAr/TtAr), and cortical thickness (CtTh). The CtTh at the masseteric ridge was used to assess the cortical bone morphology in the mandible. The trabecular bone microarchitecture and cortical bone morphology in the femoral necks and mandibles of the control group were compared with those of the ovariectomized group. Furthermore, Spearman’s correlation (rs) was conducted to analyze the correlation between the osteoporosis conditions of the mandible and femoral neck.ResultsRegarding the trabecular bone microarchitectural parameters, the BV/TV of the trabecular bone microarchitecture in the femoral necks of the control group (61.199±11.288%, median ± interquartile range) was significantly greater than that of the ovariectomized group (40.329±5.153%). Similarly, the BV/TV of the trabecular bone microarchitecture in the mandibles of the control group (51.704±6.253%) was significantly greater than that of the ovariectomized group (38.486±9.111%). Furthermore, the TbSp of the femoral necks in the ovariectomized group (0.185±0.066 mm) was significantly greater than that in the control group (0.130±0.026mm). Similarly, the TbSp of the mandibles in the ovariectomized group (0.322±0.047mm) was significantly greater than that in the control group (0.285±0.041mm). However, the TbTh and TbN trends for the mandibles and femoral necks were inconsistent between the control and ovariectomized groups. Regarding the cortical bone morphology parameters, the TtAr of the femoral necks in the ovariectomized group was significantly smaller than that in the control group. There was no significant difference in the TtAr, CtAr, or CtTh of the femoral necks between the control and ovariectomized groups, and no significant difference in the CtTh of the mandibles between the control and ovariectomized groups. Moreover, the BV/TV and TbSp of the mandibles were highly correlated with those of the femurs (rs = 0.874 and rs = 0.755 for BV/TV and TbSp, respectively). Nevertheless, the TbTh, TbN, and CtTh of the mandibles were not correlated with those of the femoral necks.ConclusionAfter the rats were ovar...

Effect of ovariectomy in bone structure of mandibular condyle

“…The thickness in the OVX group were significantly lower than those found in the SHAM group, and the trabecular separation was 4-fold higher in the OVX group than in the sham group. With a more approximated experimental design of this work, Hsu et al 28 found results similar to this work, by microcomputed tomography, but in other regions that are mandible and femoral neck.…”

Bone quality evaluation of experimental osteometabolic disease in Pantanal alligators (Caiman yacare) by High Resolution Computerized Microtomography (μCT)

“…The Percent Bone Volume parameter determines the ratio of bone volume within the Volume-of-Interest Object that is used to measure bone mass related to non-mineralized tissue of the sample (Cesar et al 2013, Hsu et al 2016, Longo et al 2017. In this study, the percentage in group G3 and G4 were higher for both trabecular bone and cortical bone compared to group G1 and G2.…”

“…For a general analysis of the cortical and trabecular bone, the following parameters were considered: Tissue Volume, Bone Volume, and Percent Bone Volume, especially when assessing the relationship between the bone matrix and other tissues. Tissue Volume was essentially based on bone structure since tíbia samples were dissected (Buie et al 2007, Larriera et al 2011, Hsu et al 2016, which was different from other studies performing in vivo analysis (Link et al 1999, Wehrli et al 2003, Buie et al 2007). The result for Bone Tissue Volume was similar to Bone Volume.…”

“…Total porosity (Po (tot), %)of trabecular bone of groups G1, G2, G3, and G4 for Pantanal alligator (Caiman yacare) tibia. Salmon et al 2015, Longo et al 2016, 2017, Hsu et al 2016). This technique has been used to for bone quality assessment in different experimental designs as 87 animal species being 69 mammals, 17 birds, and one alligator (Syahrom et al 2011, Salmon et al 2015, Hsu et al 2016, Longo et al 2016, 2017.…”

“…Salmon et al 2015, Longo et al 2016, 2017, Hsu et al 2016). This technique has been used to for bone quality assessment in different experimental designs as 87 animal species being 69 mammals, 17 birds, and one alligator (Syahrom et al 2011, Salmon et al 2015, Hsu et al 2016, Longo et al 2016, 2017. For this study, μCT was applied for assessment of Pantanal alligator tíbia that had been fed with hyperphosphatemic or balanced diets associated or not with sun exposure and that had developed lesions of fibrous osteodystrophy (Fig.4).…”