Alveolar bone loss and aging: A model for the study in mice

Background: Several animal studies have shown a positive correlation between aging and alveolar bone loss (ABL). The purpose of this study was to develop a model for the study of ABL in mice and aging. Methods: Mucoperiosteal flap surgery (MFS) was performed on the buccal aspect of the left side of the mandible (BL) in 72 CF₁ Mus domesticus mice and divided into three groups as follows: males, breeding (non-virgin) females, and virgin females. The MFS was performed in 3-, 6-, 9-, and 12-month-old animals under anesthesia. The buccal aspects of right hemimandibles were used as controls (BR). Animals were sacrificed under anesthesia 21 days after surgery. Mandibles were removed, defleshed, stained with toluidine blue, and photographed in a microscope. The photographs were digitized, and ABL was measured as the exposed root surface area (mm²). Blinded measurements were performed using a computer-assisted image analysis system. Results: In terms of alveolar bone loss, the BL (operated) area showed a significant difference (paired Student t test; P <0.001) when compared to the BR area in all three groups. Sex and breeding differences were not observed in this experiment. ABL in the left hemimandibles was significantly larger in 3- (mean: 0.70; 95% confidence interval [CI]: 0.59 to 0.80) and 12-month-old animals (mean: 0.58; 95% CI: 0.46 to 0.71) than in 6- (mean: 0.39; 95% CI: 0.33 to 0.46) and 9-month-old animals (mean: 0.42; 95% CI: 0.35 to 0.48); P <0.001. Conclusion: The results suggest that 3-month-old CF₁ mice, in a sex and breeding independent process, could be a useful model for provoked alveolar bone loss studies in aging.