title: Altered distribution of HMGB1 in the periodontal ligament of periostin-deficient mice subjected to Waldo's orthodontic tooth movement.
abstract: Periostin is essential for the integrity and function of the periodontal ligament (PDL), and periostin knockout is related to an enhanced inflammatory status in PDL. High mobility group box 1 (HMGB1), a late inflammatory cytokine, is up-regulated in PDL cells in response to mechanical stress. This study aimed to investigate the effect of periostin deficiency (Pn-/-) on HMGB1 expression in PDL during orthodontic tooth movement. We used 8-week-old male mice homozygous for the disrupted periostin gene and their wild-type (WT) littermates. Tooth movement was performed according to Waldo's method, in which 0.5-mm-thick elastic bands were inserted between the first and second upper molars of anesthetized mice. After 3 days of mechanical loading, mice were fixed by transcardial perfusion of 4% paraformaldehyde in phosphate buffer, and the maxilla was extracted for histochemical analyses. Compared with the WT group, Pn-/- mice showed higher basal expression of HMGB1 in the absence of mechanical loading. Following 3 days of orthodontic tooth movement, the PDL in the compression side of both groups was almost replaced by cell-free hyaline zones, and Pn-/- mice showed a much wider residual PDL than WT mice. In the tension side, the number of HMGB1-positive cells in PDL in both Pn-/- and WT groups increased remarkably without a significant difference between the two groups. Our findings suggest an inhibitory effect of periostin on HMGB1 production by PDL and confirmed the critical role of periostin in integrity of PDL collagen fibrils during orthodontic tooth movement, although mechanical loading is the predominant stimulant of HMGB1 expression relative to periostin deficiency.
authors.affiliation: Department of Bone Metabolism, School of Stomatology, Shandong University, Shandong Provincial Key Laboratory of Oral Biomedicine, Wenhua West Road 44-1, Jinan, 250012, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Li
authors.forename: Wei
authors.initials: W
authors.lastname: Feng
authors.forename: Bo
authors.initials: B
authors.lastname: Liu
authors.forename: Bao
authors.initials: B
authors.lastname: Sun
authors.forename: Xiuchun
authors.initials: X
authors.lastname: Han
authors.forename: Juan
authors.initials: J
authors.lastname: Du
authors.forename: Jing
authors.initials: J
authors.lastname: Sun
authors.lastname: Yimin
authors.forename: Jian
authors.initials: J
authors.lastname: Cui
authors.forename: Jie
authors.initials: J
authors.lastname: Guo
authors.forename: Akira
authors.initials: A
authors.lastname: Kudo
authors.forename: Norio
authors.initials: N
authors.lastname: Amizuka
authors.forename: Minqi
authors.initials: M
authors.lastname: Li
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D015815:Cell Adhesion Molecules / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D005786:Gene Expression Regulation; D024243:HMGB1 Protein / Q000235:genetics / Q000378:metabolism*; D008297:Male; D018345:Mice, Knockout; D009928:Organ Specificity; D010513:Periodontal Ligament / Q000378:metabolism*; D014087:Tooth Movement Techniques
chemical_list: D015815:Cell Adhesion Molecules; D024243:HMGB1 Protein; C582808:HMGB1 protein, mouse; C082838:Postn protein, mouse