Comparison of mandibular trabecular structures between normal and diabetic rats. Evaluation of spontaneous type 2 diabetes in a rat model

The objective of this study was to investigate the effect of diabetes on the trabecular structure of the mandible in an animal model of spontaneous diabetes mellitus. Glucose tolerance tests were performed and the urine glucose level monitored in nine Goto-Kakizaki diabetic rats (DM group) and nine Wistar rats (control group) from their 8th to 81st weeks of life. Mandibular molar bone was resected and evaluated by peripheral quantitative computed tomography to analyze bone mineral density (BMD), cross-sectional morphology, and the bone strength index. Micro-computed tomography was performed to evaluate the three-dimensional structure of bone from the same site, including the alveolar crest level. The morphometric indices, connectivity index, and continuity index were also determined. The alveolar crest level did not significantly differ between the DM and control groups. Trabecular BMD was significantly decreased in the DM group compared with that in the control group, but there was no significant difference in the cortical BMD. Parameters indicating morphological changes and the Stress/Strain Index, an indication of bone strength, were significantly decreased in the DM group compared with those in the control group. Morphometric indices, the connectivity index, and the continuity index showed a coarser trabecular structure in the DM group than in the control group. The diabetic condition has a significant effect on the mandibular trabecular structure, which may lead to deterioration in bone quality. (author)