Effect of sodium alendronate on alveolar bone resorption in experimental periodontitis in rats

Abstract

Background: Bisphosphonates are potent inhibitors of bone resorption and were shown to inhibit bone resorption in experi- mental periodontitis by unknown mechanisms. We studied the effect of the aminobisphosphonate sodium alendronate (SA) in experimental periodontitis. Wistar rats were subjected to liga- ture placement around the second upper left molars. Methods: Animals were treated with SA 0.01 to 0.25 mg/kg subcutaneously (sc), either 1 hour before (prophylactic) or starting 5 days after (therapeutic) periodontitis induction and daily until the rats were sacrificed (11 days). Controls received saline. Animals were weighed daily. Alveolar bone loss was measured as the difference (in millimeters) between the cusp tip and the alveolar bone. The periodontium and the sur- rounding gingivae were examined at histopathology, and the neutrophil influx into the gingivae was assayed using myeloper- oxidase activity. The local bacterial flora was assessed through culture of the gingival tissue in standard aerobic and anaerobic media. Results: Alveolar bone loss was significantly and dose de- pendently inhibited by SA either as a prophylactic or therapeu- tic treatment compared to the control. SA reduced tissue lesion at histopathology, with partial preservation of the periodonti- um, coupled to decreased myeloperoxidase activity compared to the control. The reduced neutrophil influx was also shown in carrageenan-induced peritonitis, used as a control experiment for this parameter. SA also significantly inhibited the growth of pigmented bacilli and Fusobacterium nucleatum, which are im- portant in the pathogenesis of periodontal disease. SA also inhibited the in vitro growth of isolated Peptostreptococcus sp. Conclusion: Sodium alendronate preserves alveolar bone re- sorption and has anti-inflammatory and antibacterial activities inexperimentalperiodontitis. J Periodontol 2005;76:1901-1909