Orthodontic Root Resorption was Associated with the Secretion of IL-6 and IL-8 Stimulated by IL-17in Dental Pulp Cells

Protein and mRNA expressions of IL-6 and its key signaling factors under orthodontic forces in mice: An in-vivo study

INTRODUCTION

The purpose of this study was to investigate the mechanical loading-induced changes in protein and mRNA expressions of interleukin-6 (IL-6) and its key signaling factors glycoprotein 130 (gp130), signal transducer and activator of transcription 3 (STAT3), and the Src homology phosphotyrosine phosphatase (SHP2) at the tension and compression sides of the teeth in mouse models.

METHODS

A total of 55 C57B/6 mice (10 weeks old) were divided into 3 groups. Orthodontic force was applied in group A (experimental group, n = 30); the tooth movement device was placed without activation in group B (sham control group, n = 15), and group C (blank control group, n = 10). Tooth movement was induced by a nickel-titanium coil spring inserted between the maxillary left incisor and the first molar with a force of approximately 4 g. The animals were killed 12 days after the interventions; protein and mRNA expressions of IL-6, gp130, STAT3, and SHP2 in the periodontal tissues were observed with immunohistochemistry and in-situ hybridization, respectively.

RESULTS

In contrast with the control groups, we observed enhanced expressions of IL-6, gp130, STAT3, and SHP2 protein and mRNA at the mesial and distal sides of the teeth with application of orthodontic forces in the experimental group. In contrast with the distal side, we observed enhanced expression of gp130 protein and mRNA at the mesial side in the experimental group.

CONCLUSIONS

We observed enhanced expression of IL-6 and its key signaling factors gp130, STAT3, and SHP2 protein and mRNA at the tension and compression sides of the teeth with application of orthodontic forces. The mechanical loading applied for orthodontic tooth movement might induce changes in protein localization and mRNA expression patterns of IL-6 and its key signaling factors gp130, STAT3, and SHP2 at the tension and compression sides of the periodontal ligaments of the teeth in mouse models. The result might demonstrate the special role of IL-6 and its key signaling factors in the alveolar bone-modeling process.