Evaluation of Neoformation Bone in Rat Models Treated with Bisphosphonates

Objectives: Bisphosphonates are drugs used to treat various bone diseases as osteoporosis. Are analogs of inorganic pyrophosphate, an endogenous regulator of bone mineralization. Once administered, the drug is able to bind to bone, particularly in places under remodeling. Knowing the events to which bisphosphonate is associated, this study aims to evaluate the craniofacial bone formation in animals subjected to treatment with bisphosphonates.
Methods: Were selected 65 adult female rats and ovariectomized bilaterally. The estragiol dosage was done in 15, 30 and 45 days in 13 rats randomly selected to assess homone reduction. In the second stage, 45 days after the ovariectomy, the rats were divided into groups to subcutaneous application of biphosphonates. After 30 days, the surgeries of bone defect in the central region of parietal bone were performed. The euthanasia of rats occurred in 15 and 45 days after bone defect. The pieces were stored in formaldehyde 37% and decalcified in EDTA for histological and immunohistochemical preparation.
Results: The results obtained in estradiol levels were subjected to statistical analysis to compare results at different times (p≤0,05). After 15 days, the median dose was 20,7pg/ml (20.0 - 35.4). From the time of 30 days, the median was 20 pg/ml (20.0 - 62.8) and 45 days time, the value was 20 pg/ml (20.0 - 50.4). Then, is possible to confirm that after the initial phase, there is no difference over time in relation to the concentrations of estradiol after ovariectomy, despite hormonal offsets that may occur by the adrenal.
Conclusions: With ovariectomy, the rats had decreased estrogen production, favoring an early process of osteoporosis (also on day 15). The immunostaining results for MMP-2, MMP-9 and Ki-67 are not yet available.