• Restorative Dentistry and Endodontics
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• v.24 no.1
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• pp.76-87
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• 1999

The effect of retrograde root-end filling materials(IRM, Super-EBA, Vitremer, MTA) on human periodontal ligament fibroblasts and osteoblasts was observed. The cell activities were evaluated by MTT assay, protein assay and alkaline phosphatase activity examination. The results as follows ; 1. After 24hrs culture, both E1 cells & PDL fibroblast adding root-end filling materials were suppressed cell activities but after 48hrs, cell activities were recovered. 2. Cell activity was lowest in Vitremer followed by IRM, MTA, Super-EBA. 3. Cell activity depression by Vitremer was not concerned with pH changes. 4. Protein synthesis by root-end filling materials were not significant difference in Both E1 cell & PDL fibroblasts but protein synthesis were a little increased by Super-EBA. 5. Alkaline phosphatase activity was increased in E1 cell by Super-EBA & MTA but was not significant differences in E1 cell by IRM & Vitremer. Alkaline phosphatase activity was a little depressed in PDL fibroblast by Vitremer. This findings suggest that these root-end filling materials may have important roles in promotion of PDL healing and consequently may be useful for clinical application in apical surgery.

• Journal of Periodontal and Implant Science
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• v.37 no.1
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• pp.45-51
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• 2007

This study evaluated the possibility of the 3-dimensional attachment of human periodontal ligament fibroblasts to a periodntally involved root surface after an EDTA treatment in vitro. The human PDL fibroblasts were isolated from the middle third of the root of periodontally healthy teeth extracted for orthodontic reasons. The cells were cultured in a medium containing Dulbecco's modified Eagle medium supplemented with 10% fetal bovine serum at $37^{\circ}C$ in humidified air containing 5% $CO_2$. Eight single-rooted teeth were obtained from patients diagnosed with periodotitis. After scaling and root planing, four teeth were etched with 24% ethylenediaminetetracetic acid (EDTA) for two minutes (Experimental group). The other four teeth were not treated with EDTA and were used as the control group. The human PDL fibroblasts were placed in the total root surface and cultured for 4 weeks. The teeth were fixed in 2.5% glutaraldehyde in PBS before preparation for the scanning electron microscopy (SEM) examination. The human PDL fibroblasts showed a healthy morphology on the root surfaces treated with EDTA (Experimental group) and a relatively unhealthy appearance on the treated root surfaces (Control group). This suggests that EDTA favorably affects the 3-dimensional attachment of human PDL fibroblasts cultured on the root surfaces. which may play an important role in periodontal healing and regeneration.

• The korean journal of orthodontics
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• v.49 no.5
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• pp.299-309
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• 2019

Objective: This study aimed to investigate the effect of pre-applied orthodontic force on the regeneration of periodontal ligament (PDL) tissues and the underlying mechanisms in tooth replantation. Methods: Orthodontic force (50 cN) was applied to the left maxillary first molars of 7-week-old male Sprague-Dawley rats (n = 32); the right maxillary first molars were left untreated to serve as the control group. After 7 days, the first molars on both sides were fully luxated and were immediately replanted in their original sockets. To verify the effects of the pre-applied orthodontic force, we assessed gene expression by using microarray analysis and real-time reverse transcription polymerase chain reaction (RT-PCR), cell proliferation by using proliferating cell nuclear antigen (PCNA) immunofluorescence staining, and morphological changes by using histological analysis. Results: Application of orthodontic force for 7 days led to the proliferation of PDL tissues, as verified on microarray analysis and PCNA staining. Histological analysis after replantation revealed less root resorption, a better arrangement of PDL fibers, and earlier regeneration of periodontal tissues in the experimental group than in the control group. For the key genes involved in periodontal tissue remodeling, including CXCL2, CCL4, CCL7, MMP3, PCNA, OPG, and RUNX2, quantitative RT-PCR confirmed that messenger RNA levels were higher at 1 or 2 weeks in the experimental group. Conclusions: These results suggest that the application of orthodontic force prior to tooth replantation enhanced the proliferation and activities of PDL cells and may lead to higher success rates with fewer complications.

• Molecules and Cells
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• v.40 no.8
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• pp.550-557
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• 2017

The periodontal ligament (PDL) is the connective tissue between tooth root and alveolar bone containing mesenchymal stem cells (MSC). It has been suggested that human periodontal ligament stem cells (hPDLSCs) differentiate into osteo/cementoblast and ligament progenitor cells. The periodontitis is a representative oral disease where the PDL tissue is collapsed, and regeneration of this tissue is important in periodontitis therapy. Fibroblast growth factor-2 (FGF-2) stimulates proliferation and differentiation of fibroblastic MSCs into various cell lineages. We evaluated the dose efficacy of FGF-2 for cytodifferentiation of hPDLSCs into ligament progenitor. The fibrous morphology was highly stimulated even at low FGF-2 concentrations, and the expression of teno/ligamentogenic markers, scleraxis and tenomodulin in hPDLSCs increased in a dose dependent manner of FGF-2. In contrast, expression of the osteo/cementogenic markers decreased, suggesting that FGF-2 might induce and maintain the ligamentogenic potential of hPDLSCs. Although the stimulation of tenocytic maturation by $TGF-{\beta}1$ was diminished by FGF-2, the inhibition of the expression of early ligamentogenic marker by $TGF-{\beta}1$ was redeemed by FGF-2 treatment. The stimulating effect of BMPs on osteo/cementogenesis was apparently suppressed by FGF-2. These results indicate that FGF-2 predominantly differentiates the hPDLSCs into teno/ligamentogenesis, and has an antagonistic effect on the hard tissue differentiation induced by BMP-2 and BMP-4.

• 대한치주과학회:학술대회논문집
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• 1997.11a
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• pp.37-38
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• 1997

• IMMUNE NETWORK
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• v.16 no.1
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• pp.1-12
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• 2016

Th2 cell immunity is required for host defense against helminths, but it is detrimental in allergic diseases in humans. Unlike Th1 cell and Th17 cell subsets, the mechanism by which dendritic cells modulate Th2 cell responses has been obscure, in part because of the inability of dendritic cells to provide IL-4, which is indispensable for Th2 cell lineage commitment. In this regard, immune cells other than dendritic cells, such as basophils and innate lymphoid cells, have been suggested as Th2 cell inducers. More recently, multiple independent researchers have shown that specialized subsets of dendritic cells mediate Th2 cell responses. This review will discuss the current understanding related to the regulation of Th2 cell responses by dendritic cells and other immune cells.

• Journal of Periodontal and Implant Science
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• v.35 no.1
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• pp.99-109
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• 2005

It has been focused on the importance of the host inflammatory response in periodontal pathogenesis and progression, treatment has been introduced to control the host response and the method, which diminishes production and activity of MMP by doxycycline, has been used in periodontal field. MMP is a proteolytic enzyme which plays a major role in tissue destruction and MMP-1 is secreted in the periodontally healthy tissue, while MMP-8, 9, 13, etc in the inflammatory state. Among these, MMP-13 has been discovered lately and reported to degrade primarily type II collagen. Periodontal ligament (PDL) cell plays a role in destruction of periodontal tissue. This study was to evaluate the effect of doxycycline and mefenamic acid, non-steroidal antiinflammatory drug on MMP-13 mRNA expression in the rat PDL cell. Doxycycline concentration of $1{\sim}100\;{\mu}g/ml$ was added rat PDL cell and cell activity was measured by MIT assay at day 1 and 3. MMP-13 gene expression was evaluated by RT-PCR after PDL cells were pre-treated for 1hour with doxycycline (50 ${\mu}g/ml$) alone or with mefenamic acid ($10^{-6}M$), then added $IL-1{\beta}$(1.0 ng/ml) and incubated for 16-18 hours. The results are as follows: 1. Cell activity decreased Significantly at 24 and 72 hours in 100 ${\mu}g/ml$ (p<0.05). 2. Level of MMP-13 mRNA was in 20.2% increase by $IL-1{\beta}$ and in pre-treating doxycycline group, expression of $IL-1{\beta}$ induced MMP-13 mRNA was inhibited by 31% than $IL-1{\beta}$ treated only. 3. Mefenamic acid did not inhibit on the expression of $IL-1{\beta}$ induced MMP-13 mRNA, while mefenamic acid in combination with doxycycline inhibited the expression by 41% compared to only $IL-1{\beta}$ stimulation. These results suggest that doxycycline synergistically inhibit the expression of $IL-1{\beta}$ induced MMP-13 mRNA in combination with mefenamic acid.

• The korean journal of orthodontics
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• v.27 no.4 s.63
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• pp.599-605
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• 1997

The propose of this study was to evaluate the effect of cellular activity on PDL cells dependent on intermittent and continuous compressive force by determining the alkaline phosphatase activity. An intermittent and continuous compressive forces were applied on PDL cells at the confluent stage. The alkaline phosphatase activity was measured on control and experimental groups every 24, 48, 72hours. The experimental group were consist of continuous and intermittent compressive group which were compressed by $300g/cm^2$ of diaphram pump. The intermittent compressive group was connected by timer which was worked on 10 minutes and off 10minutes. The results were as follows ; 1. The alkaline phosphatase activity of intermittent compressive group was lower than control group at 24 hours(P<0.05). 2. The alkaline phosphatase activity between each groups showed no significant differences at 48hours. 3. The alkaline phosphatase activity of continuous compresssive group was significantly higher than control group at 72 hours(P<0.01).

• Journal of Periodontal and Implant Science
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• v.27 no.4
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• pp.883-908
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• 1997

Bone remodeling is characterized by the coupling of osteoclast-mediated bone resorption and osteoblast-mediated bone formation. The process is tightly regualted at the local level by an incompletely known netwotk of peptide and non-peptide fators. Nitric oxide(NO), synthesized by nitric oxide synthetase(NOS) from L-arginine, is becoming recognized as an important bioregualtory molecule in a variety of tissue, but little is known about its possible role in periodontal tissue. The purpose of this study is to investigate the expression of nitric oxide synthetase(NOS) in inflamed gingiva and the effects of cytokine on the expression of NOS protein. The expression of NOS in gingival tissue was evaluated by immunohistochemical staining for $NOS_1$, $NOS_2$, $NOS_3$. The effect of cytokine on the expression of NOS in human periodontal ligament cells and osteoblast-like HOS cells by western blot analysis. Further, we studied that NO functions in periodontal ligament cells as a regulatory molecule. PDL cells incubated with NOS inhibitor and donor. The protein expression, type I collagen & non-collagenous protein, nitrate production and cell proliferation were evaluated The results were as follows. 1. $NOS_1$, $NOS_2$, $NOS_3$ was rarely distributed in healthy gingiva, but stronger stained in gingival epithelium, endothelial cells, and mononuclear cells of inflammed gingiva. 2. The cytokine stimulated $NOS_1$, and $NOS_3$ protein were not inducing or inhibitory effect to compared with control in PDL and HOS cells. 3.Incubation of cells with combination of $TNF-{\alpha}$, $IFN-{\gamma}$, LPS result in a time dependant increase in $NOS_2$ expression, reaching a maximal level after 24 hours of stimulation. 4. The osteonectin protein inhibitory effect of NMA, inhibitor of NOS, was reversed by Larginine in dose dependant manner. 5. NMA decreased cell poliferation and nitrate production, but the inhibitory efffect of NMA was also prevented by the NO donor, sodium nitropruiside. These results suggest that exogenously synthesized NO was playing a stimulating effect on cell proliferation or on non-collagenous protein expression. Therefore NO have an important role in mediation of localized bone destruction associated inflammatory bone disease such as periodontitis.

• The korean journal of orthodontics
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• v.28 no.1 s.66
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• pp.143-153
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• 1998

Platelet-derived growth factor(PDGF) and lipopolysaccharide(LPS) may be the important regualtors of bone metabolism Exogenous PDGF is recognized to have a stimulating effect on bone resorption in organ culture but to stimulate the formation of new bone ultimately. LPS is known to be a stimulating agent on the osteoclastic activity. The purpose of this study was to evaluate the effects and the interaction of PDGF and LPS on periodontal ligament(PDL) cells which have important roles in bone remodeling. Cultured human periodontal ligament cells were tented with various concentration or PDGF and/or LPS. The cellular viability was measured by Microtitration(MTT) assay according to the lapse time of culture. The obtained results were as follows: 1. The viability of PDL cells was not different from the con01 in 0.1ng/ml of PDGF, but was significantly increased to be over the level of control in 1ng/ml of PDGF at the second day of culture, and in 10ng/m1 of PDGF at the second and the third day of culture. 2. The cellular viability was decreased in $0.5{\mu}g/ml$ or $5{\mu}g/ml$ LPS at the third day of culture. 3. Incubation with both 1ng/ml or 10ng/ml of PDGF and $0.5{\mu}g/ml$ of $5{\mu}g/ml$ of LPS resulted in the increased cellular viability at the third day, which was greater than LPS only treated group. It was greater than even the control group in 10ng/m1 of PDGF. From the above findings, we could summarize that the admixture of PDGF and LPS could not less increase the viability of the human periodontal ligament cells than PDGF only.