MicroRNA-21 promotes orthodontic tooth movement by modulating the RANKL/OPG balance in T cells

Abstract

Objectives: The present study was designed to investigate the effects of microRNA-21 (miR-21) on orthodontic tooth movement.

Methods: The orthodontic tooth movement model was established in C57BL/6 and miR-21^-/- mice with or without implantation of activated T cells. Histological and histomorphometrical analyses were performed by hematoxylin-eosin staining. Tartrate-resistant acid phosphate staining was used to analyze the osteoclast numbers during tooth movement. Enzyme-linked immunosorbent assay, reverse transcription polymerase chain reaction, and immunohistochemistry analysis were used to examine the expression of RANKL and OPG.

Results: In miR-21^-/- mice, the distance of tooth movement was retarded, the osteoclast number was decreased, and serum RANKL expression was strongly reduced. MiR-21 promoted the secretion of RANKL from activated T cells. Furthermore, activated T cells could partially rescue the decreased orthodontic tooth movement distance in miR-21^-/- mice. MiR-21 was shown to promote orthodontic tooth movement by modulating the RANKL/OPG balance in T cells.

Conclusions: The impact of miR-21 on tooth movement was better elucidated, furthering our understanding of its role and clinical applications in orthodontics.

Keywords: T cell; bone remodeling; microRNA 21; orthodontic; osteoclast; receptor activator of nuclear factor-κB ligand (RANKL).