title: Cortical Bone Morphological and Trabecular Bone Microarchitectural Changes in the Mandible and Femoral Neck of Ovariectomized Rats.
abstract: This 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.
  
  
  
  Twelve 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.
  
  
  
  Regarding 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.
  
  
  
  After the rats were ovariectomized, osteoporosis of the trabecular bone microarchitecture occurred in their femurs and mandibles; however, ovariectomy did not influence the cortical bone morphology. In addition, the parametric values of the trabecular bone microarchitecture in the femoral necks were highly correlated with those of the trabecular bone microarchitecture in the mandibles.
authors.affiliation: Department of Biomedical Imaging and Radiological Science, China Medical University, Taichung, 404, Taiwan.
authors.forename: Pei-Yu
authors.initials: PY
authors.lastname: Hsu
authors.affiliation: Department of Biomedical Engineering, Hungkuang University, Taichung, Taiwan, 433, ROC.
authors.forename: Ming-Tzu
authors.initials: MT
authors.lastname: Tsai
authors.affiliation: Department of Orthopaedics, Taichung Veterans General Hospital, Taichung, 407, Taiwan.
authors.forename: Shun-Ping
authors.initials: SP
authors.lastname: Wang
authors.affiliation: Department of Food and Nutrition, Providence University, Taichung, 433, Taiwan.
authors.forename: Ying-Ju
authors.initials: YJ
authors.lastname: Chen
authors.affiliation: Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan, 112, ROC.
authors.forename: Jay
authors.initials: J
authors.lastname: Wu
authors.affiliation: School of Dentistry, College of Medicine, China Medical University, Taichung, 404, Taiwan.|Department of Bioinformatics and Medical Engineering, Asia University. Taichung, 413, Taiwan.
authors.forename: Jui-Ting
authors.initials: JT
authors.lastname: Hsu
mesh_terms: D000818:Animals; D001835:Body Weight; D015519:Bone Density; D000071556:Cancellous Bone / Q000000981:diagnostic imaging / Q000502:physiology; D000071538:Cortical Bone / Q000000981:diagnostic imaging / Q000502:physiology; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000502:physiology; D005272:Femur Neck / Q000000981:diagnostic imaging / Q000502:physiology*; D021621:Imaging, Three-Dimensional; D008334:Mandible / Q000000981:diagnostic imaging / Q000502:physiology*; D010052:Ovariectomy; D051381:Rats; D017208:Rats, Wistar; D055114:X-Ray Microtomography