Abstract
Objectives: Leptin has recently been shown to have an effect on bone formation, though the relationship between leptin deficiency and mandibular bone mass has not been fully elucidated. In the present study, we investigated the effects of leptin deficiency on mandibular bone structure.
Materials and Methods: Fifteen 5-week-old ob/ob mice and fifteen 5-week-old lean mice were used in the present study. Five from each group were euthanized at 6,9, and 12 weeks of age, after which the mandibles and femurs were extracted. The specimens were analyzed by means of cephalometry, and subjected to three-dimensional measurements of bone density and bone strength using peripheral quantitative computed tomography (pQCT).
Results: The mean body weight of the ob/ob mice increased significantly compared to that of the lean mice. Cephalometry findings showed that the mean length of the femur in ob/ob mice was significantly shorter than that in the lean mice. In the cephalometry of the mandibles, numerous parameters of length in the anterior-posterior direction in lean mice were significantly higher than those in ob /ob mice at each age. In contrast, parameters of height in the superior-inferior direction (Al' -Me) in ob/ob mice were significantly higher than that in lean mice at each age. pQCT analyses of bone density and bone strength showed that all parameters for the mandibles, except for trabecular bone mineral content and cross-sectional area, in ob/ob mice were significantly greater than those in lean mice. In contrast, the diaphysis of the femurs in ob/ob mice was significantly smaller.
Conclusions: Mandibles and femurs in ob/ob mice showed different architectural characteristics compared to those of lean mice.
