Inhibitory effect of infliximab on orthodontic tooth movement in male rats.

Objective: This study aimed to investigate the effect of infliximab on orthodontic tooth movement in rats.

Materials And Methods: Sixty male Sprague-Dawley rats were randomly divided into two groups: saline group and infliximab group. The two groups of rats received weekly intraperitoneally injection of saline or infliximab (5 mg/kg), respectively. After four weeks of injection, five rats in each group were euthanized and orthodontic appliances were placed in the other twenty-five rats each. On days 1, 3, 7, 14 and 21, five rats from each group were euthanised. Maxillae of all the rats were collected and examined by micro-computed tomography, haematoxylin and eosin staining, tartrate-resistant acid phosphatase staining, and immunohistochemical staining of tumour necrosis factor (TNF)-α, receptor activator of nuclear factor κB ligand (RANKL), receptor activator of nuclear factor κB (RANK), and osteoprotegerin (OPG). All data were analysed with Mann-Whitney test.

Results: Infliximab inhibited orthodontic tooth movement and decreased osteoclastogenesis on the compression side during orthodontic tooth movement. The elevated TNF-α level, induced by orthodontic force, was decreased by infliximab. Furthermore, infliximab reduced the expression of RANKL and RANK, while increased the expression of OPG on the compression side.

Conclusion: Infliximab inhibits orthodontic tooth movement by reducing levels of TNF-α, RANKL, and RANK, while increasing level of OPG, and decreasing osteoclastogenesis on the compression side of periodontium.