Effects of 1, 25-dihydroxyvitamin D3 on experimental periodontitis and AhR/NF-κB/NLRP3 inflammasome pathway in a mouse model

Abstract Vitamin D has been known to have important regulatory functions in inflammation and immune response and shows inhibitory effects on experimental periodontitis in animal models. However, the potential mechanism has yet to be clarified. Recent studies have highlighted Aryl hydrocarbon receptor (AhR) and its downstream signaling as a crucial regulator of immune homeostasis and inflammatory regulation. Objective: This study aimed to clarify the effect of 1,25-dihydroxyvitamin D3 (VD3) on experimental periodontitis and AhR/nuclear factor-κB (NF-κB)/NLR pyrin domain-containing 3 (NLRP3) inflammasome pathway in the gingival epithelium in a murine model. Methodology: We induced periodontitis in male C57BL/6 wild-type mice by oral inoculation of Porphyromonas gingivalis (P. gingivalis), and subsequently gave intraperitoneal VD3 injection to the mice every other day for 8 weeks. Afterwards, we examined the alveolar bone using scanning electron microscopy (SEM) and detected the gingival epithelial protein using western blot analysis and immunohistochemical staining. Results: SEM images demonstrated that alveolar bone loss was reduced in the periodontitis mouse model after VD3 supplementation. Western blot analyses and immunohistochemical staining of the gingival epithelium showed that the expression of vitamin D receptor, AhR and its downstream cytochrome P450 1A1 were enhanced upon VD3 application. Additionally, VD3 decreased NF-κB p65 phosphorylation, and NLRP3, apoptosis-associated speck-like protein, caspase-1, interleukin-1β (IL-1β) and IL-6 protein expression. Conclusions: These results implicate the alleviation of periodontitis and the alteration of AhR/NF-κB/NLRP3 inflammasome pathway by VD3 in the mouse model. The attenuation of this periodontal disease may correlate with the regulation of AhR/NF-κB/NLRP3 inflammasome pathway by VD3.

E-cadherin and CD1a expression in gingival epithelium in periodontal health, disease and post-treatment.

Background: Epithelial integrity is important for maintenance of periodontal health. It is not fully known if non-surgical periodontal therapy is capable of recreating the epithelial barrier in its functional state. Patients and Methods: Sixty-five patients (31 males and 34 females) were included in the study. They were divided into group A (healthy gingiva 16 patients), group B (gingivitis 17 patients), group C (periodontitis 17 patients), and group D (post-treatment 15 patients). Gingival samples were collected and immunohistochemical study was done using E-cadherin and CD1a antibody. Statistical analysis was done using analysis of variance (ANOVA), followed by Tukey-Kramer multiple comparison test for CD1a and Tukey's highly significant difference (HSD) test for E-cadherin. Result: There was a statistically significant difference (P<0.001) in the expression of E-cadherin between healthy (1.846±0.555), gingivitis (1.100±0.994), and periodontitis group (0.700±0.483). Similarly, there was a statistically significant difference (P<0.001) in the expression of CD1a between healthy (75.70±3.09), gingivitis (42.53±3.09), and periodontitis group (29.07±3.08). However, the expression of E-cadherin (1.242±0.653) and CD1a in post-treatment samples (52.18±2.90) was lower with no statistically significant difference when compared to health. Discussion: The significant reduction in E-cadherin and CD1a levels in periodontal disease when compared to health could possibly be a result of invasion by the periodontopathogens and its subsequent sequel. Although, the post-treatment samples showed significant improvement when compared to disease, the reduction in E-cadherin and CD1a levels when compared to gingival health suggests that the epithelial barrier was not yet fully established in its functional state.

Expression of EGFR on the rat gingival eqithelia during the experimental tooth movement / 대한치과교정학회지

The purpose of this study id to investigate the change of the EGFR mRNA expression in the rat gingival epithelium by the experimental tooth movement. We applied reciprocal force between the upper anterior teeth using NiTi open coil spring and stainless steel wire for 1, 2 3, 7 days. For the detection of EGFR mRNA, in situ hybridization was done in the tissue samples which were taken from the pressure and tension sides of teeth. The results were as follows; 1. The expression of EGFR mRNA was increased application-time dependently. a Day 1: mild expression on the basal and spinous cell layers. b. Day 2: moderate expression on the whole layers. c. Day 3: severe expression on the basal and spinous cell layers. d. Day 7: severe expression on the whole layers 2. The expression level of EGFR mRNA in the pressure and tension sides were similar during the whole period of experiment except seven day application at which the cornified layer of the tension side showed moderate expression. 3. Removal of the appliance after 7-day force application lowered the level of EGRF mRNA expression. It was returned to the mild and control (rare) level at three and seven days after the removal, respectively. In conclusion, EFGR mRNA was increased by, the experimental tooth movement on the rat ginigval epithelium. Up-regulation of EGFR mRNA in the gingival epithelium can be regarded as responses to the possible changes caused byy the physical stersses to the oral environment to maintain the homeostatic conditions of the periodontium.

Expression of epidermal growth factor receptor in the inflamed gingival epithelium and the dental follicle / 대한치과교정학회지

Epidermal growth factor(EGF), a single chain polypeptide of 53 amino acids with a molecular weight of 6,045 Da, was first isolated from the male mouse submandibular glands. EGF stimulates cellular proliferation and differentiation in several tissues and accelerates the rate of wound healing. EGF is bound to the specific receptor(EGFR) on the cell membrane of its target cell. EGFR is a transmembrane glycoprotein with a molecular weight of 170,000 Da and is detectable on a large variety of cell types and tissues. The authors investigated the expression of EGFR in the normal and inflamed human gingival epithelium to study the role of EGFR in the inflammation of the gingival epithelium, and the expression of EGFR in the dental follicle by using in situ mRNA hybridization and immunohistochenistry. The results weree as follows : 1. The expression of EGFR mRNA in the normal gingival epithelium on in situ rnRNA hybridization was mainly localized on the basal cell layer, and the spinous layer was weakly positive The granular and cornified layers were negative 2. The expression of EGFR protein in the normal gingival epithelium on inmu nohistochenustry was localized on the cornified and granular layers, and the spinous layer was weakly positive. The basal cell layer was completely negative 3. The expression of EGFR mRNA in the inflamed gingival epithelium on in situ mRNA hybridization was evenly and homogeneously distributed in the whole layers of the gingival epithelium except the eornifaed layer. The staining intensity appeared to increase progressively from the basal cell layer to the comified layer. 4. The expression of EGFR protein in the inflamed gingival epithelium on immunohistochemistry was evenly and homogeneously distributed in the whole layers of the gingival epithelium. The staining intensity appeared to increase progressively from the cornified layer to the basal cell layer. 5. Strong positive reaction was seen in the epithelial cell rests of Malassez, whereas only background staining was seen in other cells of the dental follicle. In conclusion, the up-regulation of EGFR in the inflamed gingival epithelium and the high amounts of EGFR in the epthelial cell rests of Malassez in the dental follicle can be regarded as responses to the possible damages to the oral environment to maintain the homeostatic conditions.