Topical Application of Drugs Influencing Cytoskeleton and Cell Contractility Affects Alveolar Bone Loss in Rats

Abstract

Several studies have shown that sectioning bundles of collagen fibers in the marginal gingiva during surgical procedures in animals is a distinct stimulus for alveolar bone resorption. Normally, gingival and periodontal fibroblasts, which reside on these collagen fibers, create physiological traction forces generated by the cytoskeleton. By splitting the fibers, traction forces are released, inducing changes in the cytoskeleton and cell shape. In this study, four drugs were selected, including cytochalasin D, EDTA, sodium orthovanadate, and H-7, all influencing the cytoskeleton-integrin-extracellular matrix (ECM) pathway, for their ability to reduce alveolar bone loss by local application. The drugs were applied locally only once at the site of mucoperiosteal flap surgery in a rat model. Cytochalasin D (1 microl/microl), EDTA (0.24 mg/microl), sodium orthovanadate (0.02 mg/microl), and H-7 (0.10 microl/microl), each separately, were carried by a protective paste and placed immediately after elevating the flap. The analysis of alveolar bone loss was performed 3 weeks after surgery by scanning the microradiographic films of the mandible cross-sections. The percentages of cross sections with no, moderate, or severe bone loss in treated in comparison to non-treated rats are presented. EDTA, sodium orthovanadate, and H-7 were significantly effective in reducing alveolar bone loss. They were effective in reducing the amount of severe bone loss by 53%, 20%, and 58% while increasing the number of sections with no bone loss by 25%, 23%, and 35%, respectively. Cytochalasin D reduced alveolar bone loss insignificantly. EDTA, sodium orthovanadate, and H-7 are effective in reducing alveolar bone loss in rats following mucoperiosteum surgery.