Effects of Aminobisphosphonate on Alveolar Bone of Osteoporotic Rabbits

Objectives: Estrogen depletion caused by menopause is the main factor which leads to osteoporosis and the aminobisphosphonate sodium alendronate (ALN) is commonly prescribed for its treatment. Our goal was to study the effects of ALN on the post-extraction alveolar bone repair/remodeling and bone quality in osteoporotic animals.
Methods: Osteoporosis was induced by ovariectomy (OV) in 6-month old white rabbits (Oryctolagos cuniculus). Six weeks following surgery, 8 animals were treated by oral gavage with ALN (OV+ALN) and 10 received placebo (control-OV). Six rabbits which were sham operated (control-SH) also received placebo. One month following the beginning of treatment, teeth #24 and #34 were removed. Six weeks later, teeth #14 and #44 were also extracted. One month after the second extraction procedure (initial healing) and at 6 weeks afterward (late healing), biopsies were collected with a trephine from the extraction sites of teeth #14 and #24 and subjected to High Performance Liquid Chromatography for the quantification of type I collagen and cross-link pentosidine. At the initial healing time point, 9 animals were euthanized (N=3/group) and bilateral bone segments of the mandible, encompassing the extraction sites of teeth #34 and #44, were subjected to Micro Computed Tomography for the comparison of bone volume among groups. Mean values were compared with one-way ANOVA followed by post-hoc Tukey’s test.
Results: Animals treated with ALN achieved the greatest mean volume of new formed bone at the late healing period (2-times control-OV, p<0.05). Collagen accumulated significantly more in the OV+ALN group compared with control groups, at both initial and late healing phase (2-4-times, p<0.05). Moreover, OV and OV+ALN animals presented higher amounts of the cross-link pentosidine than the SH group (p<0.05).
Conclusions: Suppression of bone remodeling by alendronate increases bone volume, collagen, and low-quality glycation-induced non-enzymatic cross-links in post-extraction alveolar healing sites of osteoporotic rabbits.