Periodontal ligament‐associated protein‐1 gets involved in experimental periodontitis

Abstract

Background and Objective Periodontal ligament‐associated protein‐1 (PLAP‐1) is an important regulator of osteogenic differentiation of periodontal ligament cells and plays important role in the homeostasis of periodontal tissues. But the role of PLAP‐1 in periodontitis is poorly understood. Expressions of PLAP‐1 in experimental periodontitis are observed to elucidate whether PLAP‐1 gets involved in the pathogenesis of periodontitis. Material and Methods Wistar rats were randomly allocated to two groups (n = 6/group): Ligation group and Control group. PLAP‐1 expression in experimental periodontitis was assessed by immunohistochemistry and collagen fibers in periodontal ligament were observed using picrosirius red staining. Expressions of PLAP‐1 and CD68 in periodontitis were colocalized by double‐labelled immunofluorescence. To further examine the relationship between PLAP‐1 and osteoclastogenesis in experimental periodontitis, acute periodontal inflammatory infiltration and alveolar bone destruction were induced by administering ligated rats with 10 ng/mL tumor necrosis factor alpha (TNF‐α; ligation + TNF‐α group, n = 6). Alveolar bone loss was observed by micro‐computed tomography (Micro‐CT), and osteoclasts were identified by tartrate‐resistant acid phosphatase staining (TRAP). Expressions of PLAP‐1 in TNF‐α stimulated human periodontal ligament cells were also detected at 24 and 48 hours by western blotting. Results PLAP‐1 expression levels in periodontal ligament cells and collagen fibers were lower in the ligation group,compared with the control group. Similarly, TNF‐α decreased PLAP‐1 expression in human periodontal ligament cells in vitro. Degradation or destruction of collagen fibers accompanied the reduced PLAP‐1 expression in the periodontal ligament in the ligation group. Colocalization of PLAP‐1 and CD68 revealed the positive relationship between PLAP‐1 and CD68+ infiltrating cells in periodontitis. More PLAP‐1‐positive inflammatory cells were found in the ligation + TNF‐α group, compared with the ligation + saline group. Conclusion PLAP‐1‐positive inflammatory cells are involved in the pathogenesis of periodontitis. An increase in PLAP‐1‐positive inflammatory cell number contributes periodontal inflammation and alveolar bone loss.

Calcitriol suppresses lipopolysaccharide‐induced alveolar bone damage in rats by regulating T helper cell subset polarization

“…Therefore, the levels of these cytokines in the periodontal tissue derived from DRs were assessed to investigate the potential of Th cell polarization toward different subsets. Although immunohistochemistry can be performed to identify immunolabeled cells (cell kind) or if a specific cell exhibits immunolabeling for a selected protein, the number of immunopositive cells was not quantified in the present study. In fact, the detected proteins RANKL and OPG (related to osteoclasts), as well as IFN‐γ, IL‐4, IL‐17, and IL‐10 (related to CD4 + T cell polarization), are extracellular secreted protein substances and are involved in a variety of physiological cellular functions as integrins, indicating that these proteins could be detected not only in the cytoplasm but also in the extracellular interstitium.…”

“…Hence, multiple tissues are included in this region, such as the alveolar bone above the line of the apex of the two tooth roots, the periodontal ligaments (PDLs) between the adjacent two roots and the gingival tissues between the two teeth. The number of inflammatory cells and osteoclasts in the DRs was counted according to the cell morphologies, as previously reported . Briefly, the DRs in each section were divided into three equidistant parts (top, middle, and bottom); then, at 400× magnification, the cell number in three randomly selected fields of each part was obtained, and the mean cell number in the DRs was then calculated .…”

“…The number of inflammatory cells and osteoclasts in the DRs was counted according to the cell morphologies, as previously reported. 30,31 Briefly, the DRs in each section were divided into three equidistant parts (top, middle, and bottom); then, at 400× magnification, the cell number in three randomly selected fields of each part was obtained, and the mean cell number in the DRs was then calculated. 32 For determination of the number of osteoclasts in HE-stained slides, the presence of 2 or more nuclei and the osteoclast localization (adjacent to the bone surface) were used as parameters to identify osteoclasts.…”

Isorhamnetin 3-O-neohesperidoside promotes the resorption of crown-covered bone during tooth eruption by osteoclastogenesis

“…www.nature.com/scientificreports www.nature.com/scientificreports/ eruption canal, the right mandibular first molar received the local administration of 18.75 mg/kg isorhamnetin 3-O-neohesperidoside by gingival injection for 4 days, while the left mandibular first molar received saline as a control. The bilateral mandibles were collected at postnatal day 11 and 13 and then fixed in 4% paraformaldehyde for 24 h. After demineralization in 10% EDTA for 1 month, serial sections 5 mm in thickness were prepared in the mesial distal direction for TRAP staining as reported previously 2,41 .…”

Expression characteristics of adiponectin and receptor activator of nuclear factor kappa B ligand in the alveolar bone of rats with periodontitis and its effect

“…As an infectious disease caused by dental plaque microorganisms occurring in the periodontal support tissues (Moon 2019), periodontitis mainly manifests itself in the destruction of local soft tissues and bone tissue absorption in periodontal tissues, which causes serious harm to human health with a high incidence, representing a major concern in patients of all ages (Romano et al 2019;Yu et al 2019). Clinically, periodontitis involves the progressive development of gingivitis, which usually affects most teeth.…”