Immunohistochemical localization of αvβ3 integrin receptor during experimental tooth movement

Abstract

During orthodontic treatment, multinucleated clast cells carry out the resorption of mineralized tissues. Adhesion of clast cells to the mineralized tissues is mediated by transmembrane cell-surface glycoproteins called integrins, specifically by the αvβ3 integrin, which plays an important role in the process of bone resorption. The role of the αvβ3 integrin in bone resorption leading to osteoporosis has been demonstrated, but its role in alveolar bone and root resorption during orthodontic tooth movement is unknown. This study examined the expression of the αvβ3 integrin during experimental tooth movement. Tooth movement was achieved in 16 male Sprague-Dawley rats (each weighing 120-200 g) with elastic bands between their maxillary first and second molars. The molar-bearing segments were dissected and processed for histologic and immunohistochemical examination. The expression of αvβ3 integrin was examined with 2 primary antibodies: a polyclonal anti-αv integrin subunit antibody and a polyclonal anti-β3 integrin subunit antibody. Negative controls were similarly processed but without incubation with primary antibodies. The αvβ3 integrin was expressed both by osteoclasts associated with alveolar bone resorption and by odontoclasts associated with root resorption during experimental tooth movement. Furthermore, the β3 integrin subunit was expressed by the epithelial rests of Malassez in the periodontal ligament. Negative controls did not show immunolabeling. The αvβ3 integrin adhesion receptor is expressed during experimental tooth movement and might be involved in the process of mineralized tissue resorption and the functions of the epithelial rests of Malassez.