Regulation of high mobility group box protein 1 expression following mechanical loading by orthodontic forces in vitro and in vivo

Abstract

These data indicate a potential role for HMGB1 protein originating from PDL cells in the regulation of orthodontic tooth movement and the periodontal remodelling process by modifying the local microenvironment.

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

“…Interestingly, the compression side of PDL was almost replaced by cell-free hyaline zones except for a few residual cells and exhibited negative for HMGB1. In this point, our results were contrary to that of Wolf's which showed stronger effect of orthodontic treatment on HMGB1 expression at compression side compared to tension side (Wolf et al 2013). In a systematic review of the literature on hyalinization in relation to experimental tooth movement in rat/mouse, the applied forces ranging from 0.012 to 0.50 N induced the first appearance of hyalinization within as early as the first 24 h and lasted for 1-34 days.…”

“…In the tension side, PDL cells showed strong immunolabeling for HMGB1 after the application of orthodontic force which was accordance with previous report (Wolf et al 2013 periodontal inflammation were also observed in this side which were resulted from the elastic band slipped into gingival sulcus during inserting operation or chewing. The elastic band mechanically damaged the PDL while facilitating the stick of bacteria plaque to local tissue and therefore aggravated periodontal inflammation.…”

“…Different loading ways derived from above mentioned methods are always followed by diverse histological changes of periodontal tissue. In this study, our results demonstrated that HMGB1 expression in periodontal tissue is modulated by orthodontic tooth movement and the changes of expression pattern of HMGB1 induced by Waldo's method differ from those triggered by coil spring method described by Wolf et al (2013), with the enhanced immunolocalization for HMGB1 presented in the tension side of PDL, apical tissue and dental pulp while absent in the compression side of PDL as the formation and maintenance of cell-free hyaline zones.…”

“…HMGB1 was shown to participate in the inflammation responses to mechanical force in periodontal tissue of orthodontic tooth movement model of rat (Wolf et al 2013). To our knowledge, the methods used for establishing tooth movement model comprise the following two: One was described by Waldo and Rothblatt (1954) in which the elastic band was inserted into the space between the first and second maxillary molar to generate a mechanical force (Waldo and Rothblatt 1954).…”

“…As the initial force is always overloaded, Waldo's method prone to induce sterile tissue necrosis in the compression side which is an obstacle to tooth movement and periodontal tissue remodeling. Recently, Wolf et al (2013) examined the expression pattern of HMGB1 by PDL cells followed by mechanical loading using a coil spring between the first molar and the incisor in a rat tooth movement model and found a time-dependent expression of HMGB1 in both compression side and tension side of PDL. But whether the HMGB1 expression pattern of periodontal tissue in Waldo's tooth movement model is similar to that of coil spring induced model is still unknown.…”