A Longitudinal Study of the Effect of Experimental Osteoporosis on Bone Trabecular Structure in the Rat Mandibular Condyle

Abstract

The authors performed a longitudinal study of the microstructural changes occurring in the mandibular condyle during osteoporosis using the findings obtained from micro-CT. The subjects used in this study were eight Sprague-Dawley rats. Among them, five were administered the immunosuppressant drug FK506 by injection for five weeks, while the other three were administered saline solution in the same manner. Micro-CT images were taken of the bilateral mandibular condyle, hip, and knee joints in all animals on days 1, 8, 15, 22, 29, and 36 following injection. Six indices of morphometric analysis were compared between the two groups. Significant differences were observed in BV/TV, Tb.Th, Tb.N, and Tb.Sp in the mandibular condyle, while trabecular bone density appeared to decrease in the immunosuppressant group on three-dimensional (3D) imaging. And, in comparison with the mandibular condyle and femur, they were similar. These results suggested that osteoporosis affects not only the femur, but also the mandibular condyle.

Micro-CT analysis of the rodent jaw bone micro-architecture: A systematic review

“…Two articles described bone alterations in both maxilla and mandible [3], [7], and two in mandible and condyle [11], [19]. Six studies applied in vivo micro-CT, performed in the maxilla [6], [15], [20], [21] and in the condyle [10], [22]. The scanning device which was most often used was the μCT 40 (Scanco Medical, Brüttisellen, Switzerland) [9], [11], [13], [14], [19], [23], [24], [25], [26], [27], [28], [29], [30], [31], followed by the Skyscan apparatus (Skyscan, Aartselaar, Belgium) [3], [4], [8], [20], [21], [32], [33], [34], [35].…”

“…Two longitudinal studies [10], [22] on condylar micro-architectural changes in response to experimental interventions such as osteoporosis and occlusal loading were retrieved. With regard to the effect of loading, one study focused on the therapeutic effect of a synthetic bone mineral preparation (as a diet supplement) to reduce the alveolar bone loss in female rats subjected to a mineral deficient diet [11], while another one investigated the effect of direct loading via mechanical vibration on the condylar bone [33].…”

“…The literature search also identified 16 reports dealing with interventions which potentially impact the bone micro-architecture and the bone healing or regeneration, with 6 studies applying to the maxilla [3], [4], [8], [15], [16], [23], 6 to the mandible [3], [11], [32], [40], [41], [43] and 4 to the condyle region [10], [22], [28], [46]. It is evident that the control groups included in these studies offer the possibility to extract bone micro-architectural parameters that characterize the physiological bone micro-architectural state.…”

“…With regard to the maxillofacial bone and teeth, micro-CT analysis has been mainly used to evaluate alveolar bone remodelling [3], [4], [5], the dynamic changes in periodontal ligament thickness [6] as well as specific osseous sites in the cortical and trabecular bone compartment [7], [8], [9], [10], [11], [12], [13]. However, many of such studies have used micro-CT imaging analyses without detailed description of the applied methodological parameters such as region of interest, the histograms of grey level, the scripts used in the analysis software and the outcome variables.…”

Effect of ovariectomy in bone structure of mandibular condyle

“…The mechanisms that occur in ovariectomized rats are the same as occur in humans, mimicking the post-menopausal condition. Thus this animal model is suitable for studies related to post-menopausal osteoporosis and has been used in many studies 10,11 . Preliminary studies using this animal model indicate cortical and spinal cord bone loss and that this is due to estrogenic suppression 12 .…”