Neural sodium voltage-gated channel beta subunit 3 and alpha subunit 7 distributions in mouse periodontal ligaments after experimental tooth movement

PurposeDistributional changes of beta subunit 3 (SCN3B) and alpha subunit 7 (SCN7A) proteins of voltage-gated sodium channel proteins were investigated in the periodontal ligament (PDL) after experimental tooth movement to understand their roles in pain transmission and bone remodelling during orthodontic tooth movement.Materials and methodsImmunohistochemical staining for SCN; SCN and tartrate-resistant acid phosphatase (TRAP); and SCN, calcitonin gene-related peptide (CGRP), and TRAP were performed on the PDL in the first molar teeth of mice at 1-14 days after experimental tooth movement.ResultsIn intact animals, the PDL of the first molar tooth had only a few SCN3B-immunoreactive (-IR) nerve fibres. At 5 days, however, SCN3B-IR nerve fibres significantly increased in the compression area of the PDL. SCN3B-IR nerve fibres were occasionally detected in the vicinity of TRAP-positive multinuclear cells within the resorption lacunae. These nerve fibres appeared to contain CGRP-immunoreactivity. At 7-14 days after tooth movement, SCN3B-IR nerve fibres decreased in the compression area and were infrequent in both compression and tension areas. In contrast, SCN7A-IR nerve fibres decreased in the compression area after the experimental tooth movement.ConclusionsExperimental tooth movement changed the distribution of SCNs in the PDL. SCN3B may be associated with nociceptive transmission and regulate activity of osteoclasts through release of CGRP from sensory nerve endings during orthodontic tooth movement.