Abstract
Bisphosphonates are anti-resorptive agents used for the treatment of bone diseases, such as osteoporosis. These drugs bind to bone tissue and when they are engulfed by osteoclasts during their resorptive activity, these cells undergo apoptosis. Although all osteoclasts were considered the same, there are indications that these cells present different formation and activity in different bone sites. However, no studies are found in the literature evaluating whether the antiresorptives differentially affect biophysical and/or biomechanical properties of distinct bones, as well as the osteoclasts from these sites. Therefore, the purpose of this study is to investigate in vivo the effect of a bisphosphonate (sodium alendronate) on bone sites that differ in embryological origin (ectomesenquimal versus mesodermal) and type of ossification (intramembranous versus endochondral). For this purpose, 12 adult male rats were divided into two groups receiving subcutaneous injections of Sodium Alendronate (ALE) (1mg/ml/kg, once a week) or Vehicle (VEH) (0.009mg/ml/kg saline solution, once a week). After 13 weeks of experiment, the animals were euthanized. Left femur, tibia and parietal were removed, as well as the 4th lumbar vertebra, for analyzes of biophysical and/or biomechanical analysis. Jaws and right femurs were fixed and processed for paraffin embedding. Sections stained with Picro-Sirius will be observed under a polarization microscope to analyze the arrangement and distribution of the collagen. Cortes submitted tartrate resistant acid phosphatase (TRAP) method, an osteoclast marker, will be used for the histomorphometric analysis, which will consist of counting the number of osteoclasts, obtaining its number of nuclei and area, as well as measuring the linear extension of the resorption surface. The numerical data obtained will be submitted to statistical analysis, considering p <0.05. Some preliminary results of the biophysical analysis showed that at the dosis, frequency and periods of injection, Sodium Alendronate determined a significant increase in bone volume and bone density in femurs and tibias in comparison to vehicle.
|