Expression of HMGB1 in the periodontal tissue subjected to orthodontic force application by Waldo’s method in mice

Abstract

Recent studies indicate that high mobility group box protein 1 (HMGB1) originating from periodontal ligament (PDL) cells can be a potential regulator in the process of orthodontic tooth movement and periodontal tissue remodeling. The aim of this study is to investigate HMGB1 expression in periodontal tissue during orthodontic tooth movement in mice according to Waldo's method. Six 7-week-old C57BL6 mice were used in these experiments. The elastic band was inserted into the teeth space between the right first and second maxillary molars. After 3 days of mechanical loading, mice were fixed with transcardial perfusion of 4 % paraformaldehyde in 0.1 M phosphate buffer (pH 7.4), and the maxillary was extracted for histochemical analyses. The histological examination revealed local PDL tear at the tension side and the formation of extensive cell-free hyaline zones at the compression side. The immunolocalization of HMGB1 was significantly presented at tension side of PDL, apical area and dental pulp, whereas at the compression side of PDL, the labeling of HMGB1 was almost undetectable as the presence of hyaline zone. Taken together, we concluded that the orthodontic tooth movement by Waldo's method leads to histological changes and HMGB1 expression pattern that differ from those of coil spring method, including PDL tear and extensive hyaline zone which may severely destroy periodontal tissue and in turn impede tooth movement.

Altered distribution of HMGB1 in the periodontal ligament of periostin-deficient mice subjected to Waldo’s orthodontic tooth movement

“…In addition, by using a rat experimental tooth movement model, Wolf et al (2013c) showed HMGB1 expression was modulated in a time-dependent manner in both compression and tension sides. Our previous study also confirmed the orthodontic force-triggered up-regulation of HMGB1 in mice PDL (Lv et al 2014a). Considering the altered expression of periostin and HMGB1 in PDL cells under stress condition, it is possible that there is a correlation, direct or indirect, between both proteins, which may be involved in the modulation of stress-induced PDL remodeling.…”

“…Pn-/-mice were generated as described previously (Lv et al 2014a). In brief, the targeted disruption of the periostin gene was performed in mouse embryonic stem cells using a homologous recombination, and the inserted Neo gene was deleted in deficient mice by crossing with CAG-Gre mice to excise the neo cassette; no periostin expression was observed in Pn-/-mice.…”

Stress overload‐induced periodontal remodelling coupled with changes in high mobility group protein B1 during tooth movement: an in‐vivo study

“…Additionally, Li et al . confirmed an increase in HMGB1 translocation following exposure to mechanical cell stress within the periodontal ligament system. Interestingly, these researchers showed that HMGB1 upregulation is limited to cell‐rich periodontal ligament tissue and that no HMGB1 can be detected in cell‐free hyaline zones .…”

“… confirmed an increase in HMGB1 translocation following exposure to mechanical cell stress within the periodontal ligament system. Interestingly, these researchers showed that HMGB1 upregulation is limited to cell‐rich periodontal ligament tissue and that no HMGB1 can be detected in cell‐free hyaline zones . Based on these findings and the findings of other research groups, it can be hypothesized that as a result of expansion of hyaline zones, the overall expression of HMGB1 in the periodontal ligament can differ between studies and needs to be quantified in non‐hyaline tissue.…”

“…Recent studies have demonstrated that both the expression and location of HMGB1 are altered in periodontal tissues in response to mechanical stress in a time‐dependent manner. Through cellular‐ and molecular‐level analyses of orthodontic tooth movement, Wolf et al .…”